RU2838042C1 - Method of collecting fine coal - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industry.

SUBSTANCE: invention relates to preparation and beneficiation of coal for obtaining enriched coal product of required size and/or quality. Invention relates to a method of collecting finely dispersed coal, comprising: dehydration of a liquid wastes suspension of enriched coal, having a content of solid particles from about 3% to about 20% by weight, to produce fine coal having: particle size of 1000 mcm or less and ash content from about 3% to about 28% by weight; wherein dehydration of liquid wastes suspension of enriched coal includes centrifugation of suspension in centrifuge with solid rotor, wherein the centrifuge comprises a rotating rotor, an internal auger and an overflow partition, based on the properties of the suspension of liquid waste of the enriched coal, the properties of the finely dispersed coal or both, at least one parameter is regulated: torque under action of centrifugal force, difference of rotation speeds between rotating rotor and internal auger and saddle height of overflow partition.

EFFECT: dehydration of suspension of liquid wastes of enriched coal with possibility of obtaining fine coal with specified characteristics.

18 cl, 2 dwg

Description

Cross reference to related application

This application is separated from Russian Federation patent application No. 2017123379 for an invention, filed on May 28, 2015. This patent application claims priority to U.S. Provisional Patent Application No. 62/008,389, filed on June 5, 2014, the contents of which are fully incorporated into this application by reference.

State of the art

Coal preparation and beneficiation plants are used to clean and/or separate run-of-mine coal to produce a clean coal product of a desired size and/or quality. For example, typical coal preparation plants may include various crushing, grinding, screening, washing, storage, density separation, froth flotation, dumping and/or flooding units. However, in typical coal beneficiation systems, some amounts of fine coal are lost because existing systems are unable to collect fine coal. Accordingly, it would be desirable to provide systems, devices and methods for collecting fine coal and thereby increasing process efficiency and reducing process waste in coal beneficiation plants. In addition, it would be desirable to provide a high-quality fine coal product that can be used in various applications, such as pulverized coal injection, as coking coal, i.e., caking coal, or as steam coal.

The essence of the invention

The present application provides a method for collecting fine coal. The method may include the following: dewatering a slurry of clean coal liquid waste having a solids content of from about 3% to about 20% by weight to obtain a fine coal having: (i) a particle size of 1000 μm or less, and (ii) an ash content of from about 3% to about 28% by weight; wherein dewatering the slurry of clean coal liquid waste includes centrifuging the slurry in a solid rotor centrifuge, wherein the centrifuge comprises a rotating rotor, a rotating screw, and an overflow weir.

In particular embodiments, the clean coal liquid waste slurry may have a solids content of from about 3% to about 17% by weight.

In particular embodiments, the fine coal may have an ash content of from about 3% to about 15% by weight.

In particular embodiments, the fine coal may have an ash content of from about 5% to about 10% by weight.

In certain embodiments, the fine coal may have an ash content of less than 6% by weight.

In particular embodiments, the method may further comprise adjusting, based on the properties of the slurry of liquid waste of the cleaned coal, the properties of the finely dispersed coal, or both, at least one parameter selected from the group consisting of centrifugal torque, the difference in rotational speed between the rotating rotor and the internal screw, and the overflow height of the weir.

In certain embodiments, the particle size of the fine coal may be 100 mesh or less.

In particular embodiments, the particle size of the fine coal may be from about 30 microns to about 150 microns.

In particular embodiments, the dewatering step may occur in a coal beneficiation circuit of a coal preparation and beneficiation plant.

In certain embodiments, the dewatering step may occur downstream of preparation and beneficiation, where fine coal having a particle size of 325 mesh or less is not collected.

In certain embodiments, the dewatering step may occur upstream of the preparation and beneficiation step, which collects fine coal having a particle size of 325 mesh or less.

In particular embodiments, the fine coal may have a BTU (British Thermal Unit/lb) heat content of from about 12,000 to about 16,000.

In particular embodiments, the fine coal may have a BTU heat content of from about 15,000 to about 16,000.

In particular embodiments, the fine coal may have a total sulfur content of from about 0.3% to about 4.5% by weight.

In certain embodiments, the fine coal may have a total sulfur content of less than 0.8% by weight.

In particular embodiments, the finely divided coal may have a volatile matter content of from about 7% to about 37% by weight.

In particular embodiments, the finely divided coal may have a volatile matter content of from about 15% to about 20% by weight.

In certain embodiments, the finely divided coal may have an oxygen content of about 20% or less by weight.

In certain embodiments, the finely divided coal may have an oxygen content of about 2% or less by weight.

The present application also provides methods for collecting fine coal. In embodiments, the methods include dewatering a slurry of clean coal liquid waste having a solids content of 30% by weight or less to produce fine coal having a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight.

The present application also provides devices and systems for collecting fine coal. The devices in embodiments comprise a centrifuge with a solid rotor that retains particles of 1000 μm or less in size.

The systems in embodiments comprise a dewatering device that retains particles of 1000 microns or less in size.

The present application also provides finely dispersed coal. In embodiments, the finely dispersed coal has a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight.

The present application also provides methods for producing coke and methods for producing iron or steel. The methods for producing coke in embodiments include heating, in the absence of air, fine coal or a mixture comprising fine coal and at least one other type of coal for a time and at a temperature sufficient to convert the fine coal or mixture into coke, wherein the fine coal has a particle size of 1000 μm or less and a water content of from about 5% to about 20% by weight. The methods for producing iron or steel in embodiments include injecting the fine coal or a mixture comprising fine coal and at least one other type of coal into a blast furnace containing coke and iron ore, wherein the fine coal has a particle size of 1000 μm or less and a water content of from about 5% to about 20% by weight.

Brief description of the drawings

Fig. 1 is a partial diagram of an installation illustrating one embodiment of a system and apparatus for collecting fine coal in a coal washing circuit of a coal preparation plant.

Fig. 2 is a cross-sectional view of one embodiment of a solid rotor centrifuge for collecting fine coal from a slurry of clean coal liquid waste.

Detailed disclosure of the invention

The present application provides methods, devices and systems for collecting fine coal. For example, these methods, devices and systems can be included in a coal washing plant to collect a portion of the fine coal that is normally lost in the system (e.g., fine coal that the system would not otherwise collect due to its size and which is either recycled continuously through the system or disposed of in a waste stream). In a typical coal washing plant, 3% or more of the processed coal may be lost because the system cannot collect fine coal.

In addition, the present application provides fine coal and methods for using it. Fine coal may have properties such as size, composition, and/or water content that make it useful in pulverized coal injection (PCI), as coking coal, i.e., caking coal, or as steam coal. For example, fine coal may be high-quality fine coal.

This application describes methods, devices and systems, as well as finely dispersed coal and methods for using it.

Methods, devices and systems for collecting fine coal

In one aspect, a method for collecting fine coal is provided. The method may include collecting fine coal from a coal preparation or beneficiation facility.

In embodiments, a method for collecting fine coal includes dewatering a slurry of clean coal liquid waste having a solids content of 30% by weight or less to obtain fine coal having a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight.

As used herein, the phrase "clean coal slurry" refers to a mixture of water and coal particles present in a system in which the ash and/or sulfur content of the coal particles has been reduced compared to the run-of-mine coal from which the coal particles were obtained. It should be understood that although the embodiments disclosed herein relate to methods, devices, and systems for collecting fine coal from a clean coal slurry, the present invention also encompasses other slurries containing particles, including coal-containing slurries other than a clean coal slurry, as well as other process slurries such as mineral, ore, and other slurries containing particles.

As used herein, the term "approximately" means plus or minus 10% of the numerical value of the number with which it is used. The amounts of certain components, such as solids or water, liquid waste slurries and fine coal, are given in this document as percentages "by weight" and, unless otherwise specified, the phrase "by weight" refers to the combined weight of the liquid waste slurry and fine coal including certain components.

The slurry of clean coal liquid waste in embodiments has a solids content of about 3% to about 25% by weight. In other embodiments, the slurry of clean coal liquid waste has a solids content of about 10% to about 20% by weight. In one embodiment, the slurry of clean coal liquid waste has a solids content of about 17% by weight.

In some embodiments, the fine coal comprises at least 95% by weight of the solid particles contained in the slurry of clean coal liquid waste. In one embodiment, the fine coal comprises at least 99% by weight of the solid particles contained in the slurry of clean coal liquid waste.

In embodiments, the water content of the fine coal is from about 5% to about 15% by weight. In particular embodiments, the water content of the fine coal is from about 5% to about 10% by weight. In further embodiments, the water content of the fine coal is from about 5% to about 7% by weight. In other embodiments, the water content of the fine coal is from about 6% to about 9% by weight. In a particular embodiment, the water content of the fine coal is about 8% by weight. In another embodiment, the water content of the fine coal is about 7% by weight. When collecting the fine coal using the methods provided herein, the fine coal may have an elevated temperature for a period of time after collection. As used herein, the term "water content" refers to the amount of water in the fine coal after the temperature of the fine coal has returned to ambient temperature after the fine coal has been collected by the methods described in this application.

In embodiments, the fine coal has a particle size of 1000 μm or less. As used herein, the phrase "particle size of about X μm to about Y μm" or "particle size of about Z μm" means that the average largest particle size of the fine coal is in the range of X μm to about Y μm or is about Z μm. The average largest particle size can be determined using any methods known in the art, including, but not limited to, light scattering methods. In other embodiments, the fine coal has a particle size of about 30 μm to about 1000 μm. In further embodiments, the fine coal has a particle size of about 30 μm to about 900 μm. In some embodiments, the fine coal has a particle size of about 30 μm to about 800 μm. In particular embodiments, the fine coal has a particle size of about 30 μm to about 700 μm. In some embodiments, the fine coal has a particle size of about 30 μm to about 600 μm. In still other embodiments, the fine coal has a particle size of about 30 μm to about 500 μm. In yet other embodiments, the fine coal has a particle size of about 30 μm to about 400 μm. In several embodiments, the fine coal has a particle size of about 30 μm to about 300 μm. In some embodiments, the fine coal has a particle size of about 30 μm to about 200 μm. In embodiments, the fine coal has a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a particle size of about 30 μm to about 125 μm. In other embodiments, the fine coal has a particle size of about 30 μm to about 100 μm. In further embodiments, the finely divided carbon has a particle size of about 30 μm to about 75 μm. In yet other embodiments, the finely divided carbon has a particle size of about 30 μm to about 50 μm. In yet another embodiment, the finely divided carbon has a particle size of about 44 μm.

In embodiments, the fine coal has a particle size of 100 mesh or less. As used herein, the phrase "particle size of X mesh or less" means that at least a significant majority of the particles of a particular sample of the same fine coal pass through X mesh, or a sieve opening of a size greater than X. The fine coal in embodiments has a particle size of 200 mesh or less. The fine coal in embodiments has a particle size of 325 mesh or less. The fine coal in some embodiments has a particle size of 100 mesh or less, wherein from about 40% to about 60% by weight of the fine coal is retained by 325 mesh openings. The fine coal in some embodiments has a particle size of 100 mesh or less, wherein about 50% by weight of the fine coal is retained by 325 mesh openings.

In general, dewatering of a slurry of clean coal waste liquid or other slurry containing particles can be performed by known dewatering devices such as various types of centrifuges that can perform solid-liquid separation.

In embodiments, dewatering a slurry of clean coal waste liquid includes centrifuging the slurry in a solid rotor centrifuge. As used herein, the phrase "solid rotor centrifuge" refers to a centrifuge having a solid outer rotor design that continuously separates two substances with different densities by centrifugal force generated by rotation. As shown in Fig. 2, in one embodiment, a solid rotor centrifuge 200 includes a solid outer rotating rotor 202 and an inner rotating scroll 204. In certain embodiments, the centrifuge 200 includes a weir 212 that controls the depth of the liquid layer in the centrifuge.

In certain embodiments, as shown in Fig. 2, during operation, an input stream 206 (or feed stream), such as a slurry of clean coal liquid waste or another slurry containing particles, is introduced into the centrifuge 200 and fed to the solid rotor 202 through one or more openings. Both the solid rotor 202 and the internal auger, or screw, 204 rotate to separate the components of the feed stream 206 depending on their densities. The auger 204 acts as a conveyor and rotates at a differential speed relative to the rotor 202 to provide continuous removal of solid particles 210 (e.g., fine coal) from the wastewater 208.

Suitable solid-bore centrifuges may include those manufactured by Centrisys Centrifuge Systems (Kenosha, Wis.). For example, a solid-bore centrifuge may include any design, features, or combination of features disclosed herein and/or known to those of ordinary skill in the art to achieve the desired separation.

In certain embodiments, the methods include further adjusting, based on the properties of the slurry of liquid waste of the cleaned coal, the properties of the fine coal, or both, at least one parameter selected from: the torque due to centrifugal force, the speed difference between the rotating rotor and the internal screw, and the crossover height of the weir. In other words, one, two, or all three of these parameters can be adjusted depending on the properties of the feed stream and/or the desired output product, such as water content, solids content, and/or particle size.

For example, the speed difference can be selected depending on the particles being separated to avoid damage and to ensure compliance with the density range. For example, solid-bore centrifuges can operate at centrifugal forces greater than 1000 times, such as 3000 times, the force of gravity so that the denser solids are pressed outward against the wall of the rotating rotor and the less dense liquid phase forms a concentric inner layer. For example, the rotation speed and torque of the centrifuge can be adjusted based on the density and/or turbidity of the feed suspension.

For example, in a slurry of liquid waste from clean coal, the fine coal may have a specific gravity of 2.0 or less, such as from about 1.5 to about 1.6, or about 1.55. Since the specific gravity of the particles may vary quite significantly due to the presence of impurities in the particles, the centrifuge parameters may be adjusted accordingly. In addition, it should be understood that a wide variety of system parameters may be adjusted, such as rotation speed, temperature, and flow rate.

Typically, these parameters can be adjusted manually or by computer control, the latter providing automatic continuous adjustment of each parameter. Computer control systems are discussed in detail below.

In embodiments, as shown in Fig. 1, the dewatering step occurs in a coal cleaning circuit of a coal preparation and cleaning plant. In the context of the present document, the phrase "coal cleaning circuit" refers to a part of a coal preparation and cleaning plant in which the ash and/or sulfur content of the coal particles is reduced compared to the run-of-mine coal from which the coal particles were obtained. Thus, in certain embodiments, a solid rotor centrifuge 106 for dewatering a slurry of clean coal liquid waste is provided downstream of one or more coal cleaning technology units 102 in a coal preparation and cleaning plant 100.

In embodiments, the dewatering step occurs downstream of the preparation and beneficiation, which does not collect fine coal having a particle size of 325 mesh or less. For example, other separators, such as centrifuges, cyclones, flotation tanks or screens, which are not suitable for collecting fine coal having a particle size of 325 mesh or less, can be located upstream of the dewatering device.

In certain embodiments, as shown in Fig. 1, the solid rotor centrifuge 106 is located downstream of the screen rotor centrifuge 104, which does not collect fine coal having a particle size of 325 mesh or less. Thus, the solid rotor centrifuge 106 is configured to and positioned to effectively collect fine coal that would otherwise be recycled in a recirculation stream or removed to a waste stream.

In embodiments, the dewatering step occurs upstream of a preparation and beneficiation that collects fine coal having a particle size of 325 mesh or less. Typically, such preparation and beneficiation includes waste treatment. For example, a preparation and beneficiation section that collects fine coal having a particle size of 325 mesh or less may include a thickener unit.

During operation, for example, in the plant layout shown in Fig. 1, if dewatering on a screen of a centrifuge with a mesh rotor occurs without recirculation, there is a significant loss of product and an increase in waste. However, if dewatering on a screen is recirculated, then the particle size distribution of the suspension decreases during the operating cycle, as a result of which the product yield decreases and wear of the screen increases. The present methods, devices and systems eliminate these disadvantages by collecting fine coal from the dewatering screen, as a result of which the product yield of the entire plant is improved and the service life of other equipment of the plant is increased. In addition, the fine coal obtained by these methods, devices and systems exhibits the properties of high-quality coal and can be used in a number of applications, as described in detail below.

Disclosed herein are methods for collecting fine coal. In embodiments, methods for collecting fine coal include dewatering a slurry of clean coal liquid waste having a solids content of 30% by weight or less to obtain fine coal having a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight. In some embodiments, dewatering the slurry of clean coal liquid waste includes centrifuging the slurry in a solid rotor centrifuge. The solid rotor centrifuge may include a rotating rotor, a rotating screw, and a weir. The methods proposed in the present application may include controlling, based on the properties of the slurry of liquid waste clean coal, the properties of the fine coal, or both, at least one parameter selected from the group consisting of a centrifugal torque, a speed difference between the rotating rotor and the internal screw, and a crossover height of the weir. The dewatering step may occur in a coal cleaning circuit of a coal preparation and cleaning plant. The dewatering step may occur downstream of the preparation and cleaning, which does not collect fine coal having a particle size of 325 mesh or less. The dewatering step may occur upstream of the preparation and cleaning, which does not collect fine coal having a particle size of 325 mesh or less. The preparation and cleaning section that collects fine coal having a particle size of 325 mesh or less may include a thickener. The slurry of liquid clean coal waste in particular embodiments has a solids content of from about 3% to about 25% by weight; from about 10% to about 20% by weight; or about 17% by weight. The fine coal in embodiments comprises at least 95% by weight of the solids contained in the slurry of liquid clean coal waste. In other embodiments, the fine coal comprises at least 99% by weight of the solids contained in the slurry of liquid clean coal waste. The water content of the fine coal in embodiments is from about 5% to about 15% by weight; from about 5% to about 10% by weight; from about 5% to about 7% by weight; from about 6% to about 9% by weight; about 8% by weight; or about 7% by weight. The particle size of the fine coal can be 100 mesh or less. In embodiments, about 40% to about 60% by weight of the fine coal is retained by 325 mesh size; or about 50% by weight of the fine coal is retained by 325 mesh size. The fine coal particle size can be 325 mesh or less. The fine coal particle size can be from about 30 μm to about 1000 μm; from about 30 μm to about 900 μm; from about 30 μm to about 800 μm; from about 30 μm to about 700 μm; from about 30 μm to about 600 μm; from about 30 μm to about 500 μm; from about 30 μm to about 400 μm; from about 30 μm to about 300 μm; from about 30 μm to about 200 μm; from about 30 μm to about 150 μm; from about 30 μm to about 125 μm; from about 30 μm to about 100 μm; from about 30 μm to about 75 μm; from about 30 μm to about 50 μm; or about 44 μm.

In another aspect, a device for collecting fine coal is provided. For example, the dewatering device may include any features disclosed in this application or a combination of features disclosed in this application and/or known to those of ordinary skill in the art to achieve the desired separation.

In embodiments, a device for collecting fine coal from a slurry of clean coal liquid waste includes a solid rotor centrifuge that retains particles of 1000 microns or less in size. For example, a solid rotor centrifuge may be configured to retain fine coal of any of the sizes disclosed in this application. In one embodiment, the solid rotor centrifuge retains particles of 100 mesh or less in size. In one embodiment, the solid rotor centrifuge retains particles of 325 mesh or less in size.

In embodiments, the device includes a solid rotor centrifuge comprising a rotating rotor, a rotating screw and an overflow partition, wherein at least one parameter selected from the group consisting of a centrifugal torque, a speed difference between the rotating rotor and the internal screw and a saddle height of the overflow partition is adjusted depending on the properties of the slurry of liquid waste of the clean coal, the properties of the fine coal, or both. In one embodiment, each parameter selected from the group consisting of a centrifugal torque, a speed difference between the rotating rotor and the internal screw and a saddle height of the overflow partition is adjusted depending on the properties of the slurry of liquid waste of the clean coal, the properties of the fine coal, or both.

In embodiments, the device includes a solid rotor centrifuge configured to dewater a slurry of clean coal liquid waste having a solids content of 30% by weight or less to produce fine coal having a water content of from about 5% to about 20% by weight.

The present application provides devices for collecting fine coal. In embodiments, the devices for collecting fine coal from a slurry of clean coal liquid waste include a solid rotor centrifuge that retains particles of 1000 μm or less in size. The solid rotor centrifuge can retain particles of 100 mesh or less in size; or 325 mesh or less. The solid rotor centrifuge can also include a rotating rotor, a rotating screw, and an overflow partition, wherein at least one parameter selected from the group consisting of a centrifugal torque, a rotational speed difference between the rotating rotor and the inner screw, and a crossover height of the overflow partition can be adjusted depending on the properties of the slurry of clean coal liquid waste, the properties of the fine coal, or both. The solid rotor centrifuge may also comprise a rotating rotor, a rotating screw and an overflow partition, wherein each parameter from the group consisting of the centrifugal torque, the rotation speed difference between the rotating rotor and the internal screw and the overflow partition overflow height may be adjusted depending on the properties of the slurry of liquid waste of the clean coal, the properties of the fine coal, or both. The solid rotor centrifuge may be configured to dewater the slurry of liquid waste of the clean coal having a solids content of 30% by weight or less to obtain fine coal having a water content of from about 5% to about 20% by weight.

In another aspect, a system for collecting fine coal is provided. For example, the system may include any features disclosed in this application or a combination of features disclosed in this application and/or known to those of ordinary skill in the art to achieve the desired separation.

In embodiments, a system for collecting fine coal comprises a dewatering device that retains particles of 1000 microns or less in size. For example, the dewatering device may be configured to retain any fine coal particle size described in this application. In one embodiment, the dewatering device retains particles of 100 mesh or less in size. In one embodiment, the dewatering device retains particles of 325 mesh or less in size. In certain embodiments, the dewatering device includes a solid rotor centrifuge.

In embodiments, the system includes a coal washing circuit of a coal preparation and washing plant, wherein the dewatering device is in the coal washing circuit. In certain embodiments, the dewatering device is downstream of the preparation and washing units that do not collect fine coal having a particle size of 325 mesh or less. In one embodiment, the dewatering device is upstream of the preparation and washing unit that collects fine coal having a particle size of 325 mesh or less. For example, the preparation and washing unit that collects fine coal having a particle size of 325 mesh or less may include a thickener.

In embodiments, the feedstock of the dewatering device includes a slurry of clean coal liquid waste having a solids content of 30% or less by weight. In certain embodiments, the feedstock of the dewatering device includes a slurry of clean coal liquid waste having a solids content of about 3% to about 25% by weight. In further embodiments, the feedstock of the dewatering device includes a slurry of clean coal liquid waste having a solids content of about 10% to about 20% by weight. In one embodiment, the feedstock of the dewatering device includes a slurry of clean coal liquid waste having a solids content of about 17% by weight.

In embodiments, the output of the dewatering device includes fine coal having a water content of about 5% to about 20% by weight. In certain embodiments, the output of the dewatering device includes fine coal having a water content of about 5% to about 15% by weight. In further embodiments, the output of the dewatering device includes fine coal having a water content of about 5% to about 10% by weight. In particular embodiments, the output of the dewatering device includes fine coal having a water content of about 5% to about 7% by weight. In other embodiments, the output of the dewatering device includes fine coal having a water content of about 6% to about 9% by weight. In one embodiment, the output of the dewatering device includes fine coal having a water content of about 8% by weight. In another embodiment, the output of the dewatering device includes fine coal having a water content of about 7% by weight.

In certain embodiments, the feedstock of the dewatering device includes a slurry of clean coal liquid waste, the output of the dewatering device includes fine coal, and the fine coal contains at least 95% by weight of the solid particles contained in the slurry of clean coal liquid waste. In other embodiments, the feedstock of the dewatering device includes a slurry of clean coal liquid waste, the output of the dewatering device includes fine coal, and the fine coal contains at least 99% by weight of the solid particles contained in the slurry of clean coal liquid waste.

In embodiments, the output of the dewatering device includes fine coal, and from about 40% to about 60% by weight of the fine coal is retained by 325 mesh size cells. In certain embodiments, the output of the dewatering device includes fine coal, and about 50% by weight of the fine coal is retained by 325 mesh size cells.

In embodiments, the feedstock of the dewatering device includes a slurry of liquid waste of clean coal, the output product of the dewatering device includes fine coal, the dewatering device includes a centrifuge with a solid rotor, comprising a rotating rotor, a rotating screw and an overflow partition, wherein at least one parameter selected from the group consisting of a torque under the action of centrifugal force, a difference in rotation speeds between the rotating rotor and the internal screw and a pass height of the overflow partition, is adjusted depending on the properties of the slurry of liquid waste of clean coal, the properties of the fine coal, or both.

In embodiments, the system includes at least one memory device that stores machine-executable instructions; and at least one controller configured to access the at least one memory device, wherein the at least one controller may be configured to execute machine-executable instructions for receiving, from an interface, data on the properties of the slurry of liquid waste of the clean coal, the properties of the fine coal, or both, and controlling, in response to receiving the data on the properties, the adjustment of at least one parameter selected from the group consisting of a torque due to centrifugal force, a difference in rotational speeds between the rotating rotor and the internal screw, and a saddle height of the overflow baffle. For example, the interface may include a manual or machine interface through which the parameters can be adjusted. In one embodiment, the interface includes at least one suitable sensor configured to determine suitable properties of the slurry of liquid waste of the clean coal.

For example, the controller(s) may include a data processing unit capable of receiving digital data as input, processing the input data in accordance with stored machine-executable instructions, and generating output data. The controller(s) may be configured to execute machine-executable instructions to cause or facilitate the execution of various operations, such as parameter adjustments. The controller(s) may be configured to use and control various hardware resources available in the devices or systems disclosed in this application to perform the various parameter adjustments, facilitate data storage, etc. The controller(s) may include any type of suitable data processing unit, including, without limitation, a central processing unit, a microprocessor, a microcontroller, a reduced instruction set computer (RISC) microprocessor, a complete instruction set computer (CISC) microprocessor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a system on a chip (SoC), etc.

The memory device may store computer-executable instructions loaded and executed by the controller(s), as well as data processed and/or generated by the controller(s) during the execution of the computer-executable instructions. The memory device may include volatile memory (memory that retains its state when power is applied), such as random access memory (RAM), and/or non-volatile memory (memory that retains its state even without power applied), such as read-only memory (ROM), flash memory, and the like. In certain embodiments, the memory device includes several different types of memory, such as various types of static random access memory (SRAM), various types of dynamic random access memory (DRAM), various types of non-volatile ROM and/or writable ROM variants, such as electrically erasable programmable read-only memory (EEPROM), flash memory, and the like. In certain embodiments, the storage device includes at least one data store.

The systems or devices may also include additional data storage(s), such as removable media and/or non-removable media, including, but not limited to, magnetic storage, optical disk storage, and/or magnetic tape storage. The data storage(s) may provide storage of machine-executable instructions and other data. The data storage(s) may include media internal and/or external to the system or device. The storage device and/or data storage(s), removable and/or non-removable, are examples of machine-readable storage media (MRSM).

The memory device may store data, machine-executable instructions, applications, and/or various software modules, including, for example, one or more operating systems, one or more database management systems (DBMS), and one or more software modules, such as a data definition module, an interface signal module, and a sensor module.

An operating system (OS) may provide an interface between other applications and/or software modules executed by a system or device and the hardware resources of the system or device. More specifically, an OS may include a set of machine-executable instructions for managing the hardware resources of a system or device and for providing common services for other applications and/or software modules (e.g., managing the allocation of memory among various applications and/or software modules). An OS may be any operating system currently known or that may be developed in the future, including, without limitation, any desktop or laptop operating system, any server operating system, any mainframe operating system, or any other specialized or non-specialized operating system.

The DBMS may support functions for accessing, retrieving, storing and/or processing data stored in one or more data stores provided externally to the dispensing system and/or internal data stores provided, for example, as part of the data warehouse(s). The DBMS may use any of a variety of database models (e.g., a relational model, an object model, etc.) and may support any of a variety of query languages. For example, the DBMS may allow external access and retrieval of data.

The system or device may further include one or more input/output interfaces that may facilitate the system or device to receive input information via one or more input/output devices configured to exchange data with the system or device, as well as to output information from the system or device to one or more input/output devices. The input/output devices may include, without limitation, a user interface such as buttons or a touch sensor, a display, a keyboard, a pointing device, a control panel, a touch display, a remote control device, a speaker, a microphone, a printer, other peripheral devices, etc. The system may further include one or more network interfaces that may provide data exchange between the system or device and other components.

It should be understood that any of the components of the systems or devices disclosed in this application may include alternative and/or additional hardware, software or firmware components in addition to those disclosed herein without departing from the scope of the disclosure of the present invention. More particularly, it should be understood that the hardware, software or firmware components described as forming part of any of the components of the system or device are merely illustrative and that in various embodiments some components may be omitted or additional components may be provided.

Although various software modules have been described in connection with various illustrative components of systems or devices, it should be understood that the functions described as supported by the software modules may be provided by any combination of hardware, software and/or firmware. It should also be understood that each of the above-mentioned modules may, in various embodiments, represent a logical partition of a supported set of functions. This logical partition is described for ease of explanation of the functions and may not reflect the structure of the hardware, software and/or firmware for implementing this set of functions. Accordingly, it should be understood that the functions described as supported by a particular module may, in various embodiments, be provided, at least in part, by one or more other modules. Moreover, one or more modules may be absent in certain embodiments, while in other embodiments, additional, undescribed modules may be present and support at least a portion of the described and/or additional functions. Furthermore, although some modules may be described as submodules of another module, in certain embodiments such modules may be provided as independent modules.

The present application describes systems for collecting fine coal. In embodiments, a system for collecting fine coal may comprise a dewatering device that retains particles of 1000 μm or less in size. The dewatering device may retain particles of 100 mesh or less in size; or 325 mesh or less. The dewatering device may comprise a solid rotor centrifuge. The system may comprise a coal cleaning circuit of a coal preparation and cleaning plant, wherein the dewatering device is in the coal cleaning circuit. The dewatering device may be downstream of preparation and cleaning units that do not collect fine coal having a particle size of 325 mesh or less. The dewatering device may be upstream of preparation and cleaning units that collect fine coal having a particle size of 325 mesh or less. The preparation and cleaning unit that collects fine coal having a particle size of 325 mesh or less may comprise a thickener. The feedstock of the dewatering device may comprise a slurry of clean coal liquid waste having a solids content of 30% or less by weight. The feedstock of the dewatering device may comprise a slurry of clean coal liquid waste having a solids content of from about 3% to about 25% by weight. The feedstock of the dewatering device may comprise a slurry of clean coal liquid waste having a solids content of from about 10% to about 20% by weight; or about 17% by weight. The output product of the dewatering device may comprise fine coal having a water content of from about 5% to about 20% by weight; from about 5% to about 15% by weight; from about 5% to about 10% by weight; from about 5% to about 7% by weight; from about 6% to about 9% by weight; about 8% by weight; or about 7% by weight. In the systems disclosed in this application, the feedstock of the dewatering device may comprise a slurry of clean coal liquid waste, the output of the dewatering device may comprise fine coal, and/or the fine coal may comprise at least 95% by weight, or at least 99% by weight, of the solids contained in the slurry of clean coal liquid waste. In the systems disclosed in this application, the output of the dewatering device may comprise fine coal, and/or from about 40% to about 60% by weight, or about 50% by weight of fine coal is retained by 325 mesh size. Also, in the embodiments disclosed in the present application, the feedstock of the dewatering device may comprise a slurry of liquid clean coal waste, the output product of the dewatering device may comprise fine coal, the dewatering device may comprise a solid rotor centrifuge comprising a rotating rotor, a rotating screw and an overflow partition, and/or at least one parameter selected from the group consisting of a centrifugal torque, a speed difference between the rotating rotor and the internal screw and a crossover height of the overflow partition may be adjusted depending on the properties of the slurry of liquid clean coal waste, the properties of the fine coal, or both. The system disclosed in the present application may also comprise at least one memory device in which machine-executable instructions are stored; and at least one controller configured to access at least one memory device, wherein the at least one controller may be configured to execute machine-executable commands for (1) receiving, from an interface, data on the properties of the slurry of liquid waste of the cleaned coal, the properties of the fine coal, or both, and (2) controlling, in response to receiving the data on the properties, the adjustment of at least one parameter selected from the group consisting of a torque due to centrifugal force, a difference in rotational speeds between the rotating rotor and the internal screw, and a saddle height of the overflow partition. The interface may comprise a manual user interface. The interface may comprise at least one sensor configured to determine the properties of the slurry of liquid waste of the cleaned coal.

Fine coal and its uses

In one aspect, fine coal is provided. Fine coal can be produced using the methods, devices and systems disclosed in this application. Fine coal can be used for pulverized coal injection (PCI), as coking coal, i.e., sintering coal, or as steam coal.

Fine coal in embodiments has a water content of about 5% to about 20% by weight. Fine coal in some embodiments has a water content of about 5% to about 15% by weight. Fine coal in other embodiments has a water content of about 5% to about 10% by weight. Fine coal in particular embodiments has a water content of about 5% to about 7% by weight.

The fine coal in certain embodiments has a water content of about 6% to about 9% by weight. The fine coal in other embodiments has a water content of about 8% by weight. The fine coal in still other embodiments has a water content of about 7% by weight. When collecting the fine coal by the methods provided herein, the fine coal may have an elevated temperature for a period of time after collection.

In embodiments, the fine carbon has a particle size of 1000 μm or less. The average largest dimension can be determined using any methods known in the art, including, but not limited to, light scattering methods. In other embodiments, the fine carbon has a particle size of from about 30 μm to about 1000 μm. In further embodiments, the fine carbon has a particle size of from about 30 μm to about 900 μm. In some embodiments, the fine carbon has a particle size of from 30 μm to about 800 μm. In particular embodiments, the fine carbon has a particle size of from about 30 μm to about 700 μm. In some embodiments, the fine carbon has a particle size of from about 30 μm to about 600 μm. In yet other embodiments, the fine carbon has a particle size of from about 30 μm to about 500 μm. In still other embodiments, the finely divided carbon has a particle size of about 30 μm to about 400 μm. In some embodiments, the finely divided carbon has a particle size of about 30 μm to about 300 μm. In some embodiments, the finely divided carbon has a particle size of about 30 μm to about 200 μm.

In embodiments, the fine coal has a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a particle size of about 30 μm to about 125 μm. In other embodiments, the fine coal has a particle size of about 30 μm to about 100 μm. In further embodiments, the fine coal has a particle size of about 30 μm to about 75 μm. In yet other embodiments, the fine coal has a particle size of about 30 μm to about 50 μm. In yet another embodiment, the fine coal has a particle size of about 44 μm.

In embodiments, the fine coal has a particle size of 100 mesh or less. The fine coal in embodiments has a particle size of 200 mesh or less. The fine coal in embodiments has a particle size of 325 mesh or less. The fine coal in some embodiments has a particle size of 100 mesh or less, wherein from about 40% to about 60% by weight of the fine coal is retained by meshes of 325 mesh. The fine coal in some embodiments has a particle size of 100 mesh or less, wherein about 60% by weight of the fine coal is retained by meshes of 325 mesh.

In embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of 1000 μm or less. In embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of 100 mesh or less. In some embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of 325 mesh or less. In further embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of 100 mesh or less, wherein about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

In embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of about 30 μm to about 50 μm. In other embodiments, the fine coal has a water content of about 5% to about 20% by weight and a particle size of about 44 μm.

In embodiments, the fine coal has a water content of about 5% to about 15% by weight and a particle size of 1000 μm or less. In embodiments, the fine coal has a water content of about 5% to about 15% by weight and a particle size of 100 mesh or less. In some embodiments, the fine coal has a water content of about 5% to about 10% by weight and a particle size of 100 mesh or less. In other embodiments, the fine coal has a water content of about 8% by weight and a particle size of 100 mesh or less.

In embodiments, the fine coal has a water content of about 5% to about 15% by weight and a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a water content of about 5% to about 10% by weight and a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a water content of about 8% by weight and a particle size of about 30 μm to about 150 μm.

In embodiments, the fine coal has a water content of about 5% to about 15% by weight and a particle size of 325 mesh or less. In some embodiments, the fine coal has a water content of about 5% to about 15% by weight and a particle size of 100 mesh or less, and about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

In embodiments, the finely divided coal has a water content of about 5% to about 15% by weight and a particle size of about 30 μm to about 50 μm. In some embodiments, the finely divided coal has a water content of about 5% to about 15% by weight and a particle size of about 44 μm.

In embodiments, the fine coal has a water content of about 5% to about 10% by weight and a particle size of 1000 μm or less. In embodiments, the fine coal has a water content of about 5% to about 10% by weight and a particle size of 325 mesh or less. In some embodiments, the fine coal has a water content of about 5% to about 10% by weight and a particle size of 100 mesh or less, and about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

In embodiments, the finely divided coal has a water content of about 5% to about 10% by weight and a particle size of about 30 μm to about 150 μm. In some embodiments, the finely divided coal has a water content of about 5% to about 10% by weight and a particle size of about 44 μm.

In embodiments, the fine coal has a water content of about 8% by weight and a particle size of 1000 μm or less. In embodiments, the fine coal has a water content of about 8% by weight and a particle size of 325 mesh or less. In some embodiments, the fine coal has a water content of about 8% by weight and a particle size of 100 mesh or less, and from about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

In embodiments, the finely divided coal has a water content of about 8% by weight and a particle size of about 30 μm to about 50 μm. In some embodiments, the finely divided coal has a water content of about 8% by weight and a particle size of 44 μm or less.

In embodiments, the fine coal has a relatively high BTU (British thermal unit/lb) heat content. As used herein, the phrase "relatively high BTU" means a BTU of about 12,000 to about 16,000 when the fine coal has a water content of about 5% to about 20% by weight. The fine coal having a relatively high BTU may be suitable for use as a coking coal, i.e., caking coal, PUC, steam coal, or a combination thereof. In certain embodiments, the fine coal has a BTU of about 12,400 to about 14,000 and a water content of about 5% to about 20% by weight. In one embodiment, the fine coal has a BTU heat content of about 12,500 and a water content of about 5% to about 20% by weight. In some embodiments, the fine coal has a BTU heat content of about 12,800 to about 16,000 and a water content of about 5% to about 20% by weight. In an embodiment, the fine coal has a BTU heat content of about 13,500 and a water content of about 5% to about 20% by weight. In particular embodiments, the fine coal has a BTU heat content of about 13,500 to about 16,000 and a water content of about 5% to about 20% by weight. In another embodiment, the fine coal has a BTU heat content of about 14,000 and a water content of about 5% to about 20% by weight. In other embodiments, the fine coal has a BTU heat content of about 14,000 to about 16,000 and a water content of about 5% to about 20% by weight. In yet other embodiments, the fine coal has a BTU heat content of about 15,000 to about 16,000 and a water content of about 5% to about 20% by weight. In further embodiments, the fine coal has a BTU heat content of about 15,500 and a water content of about 5% to about 20% by weight.

In embodiments, the fine coal has a heat content in BTU from about 12,000 to about 16,000, a water content from about 5% to about 15% by weight, and a particle size of 1000 microns or less. In embodiments, the fine coal has a heat content in BTU from about 12,000 to about 16,000, a water content from about 5% to about 15% by weight, and a particle size of 100 mesh or less. In other embodiments, the fine coal has a heat content in BTU from about 14,000 to about 16,000, a water content from about 5% to about 10% by weight, and a particle size of 100 mesh or less, wherein from about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

In embodiments, the fine coal has a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of about 30 μm to about 150 μm. In other embodiments, the fine coal has a BTU heat content of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of about 30 μm to about 50 μm.

In embodiments, the fine coal has a BTU heat content suitable for use as a steam coal. As used herein, the phrase "a BTU heat content suitable for use as a steam coal" means a BTU heat content of about 6,000 to about 13,500 when the fine coal has a water content of about 5% to about 20% by weight. In some embodiments, the fine coal has a BTU heat content of about 7,000 to about 13,500 and a water content of about 5% to about 20% by weight. In other embodiments, the fine coal has a BTU heat content of about 9,000 to about 13,500 and a water content of about 5% to about 20% by weight.

In particular embodiments, the fine coal has an ash content of about 3% to about 28% by weight. In embodiments, the fine coal has an ash content of about 3% to about 15% by weight. In some embodiments, the fine coal has an ash content of about 3% to about 10% by weight. In other embodiments, the fine coal has an ash content of about 5% to about 10% by weight. In yet other embodiments, the fine coal has an ash content of about 6% to about 8% by weight. In one embodiment, the fine coal has an ash content of about 6% by weight.

In embodiments, the fine coal has an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 1000 microns or less. In embodiments, the fine coal has an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In other embodiments, the fine coal has an ash content of from about 3% to about 10% by weight, a heat content in BTUs of from about 14,000 to about 16,000, a water content of from about 5% to about 10% by weight, and a particle size of 100 mesh or less, with about 50% by weight of the fine coal retained in 325 mesh cells.

In embodiments, the fine coal has an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of about 30 μm to about 150 μm. In other embodiments, the fine coal has an ash content of about 5% to about 10% by weight, a BTU heat content of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of about 30 μm to about 50 μm.

The fine coal, in embodiments, has a total sulfur content of from about 0.3% to about 4.5% by weight. As used herein, the phrase "total sulfur content" refers to all sulfur that may be present in the fine coal, including sulfate sulfur, organic sulfur, and inorganic sulfur. In certain embodiments, the fine coal has a total sulfur content of from about 0.3% to about 2% by weight. In particular embodiments, the fine coal has a total sulfur content of from about 0.6% to about 1.3% by weight. In some embodiments, the fine coal has a total sulfur content of from about 0.8% to about 1.3% by weight. In further embodiments, the fine coal has a total sulfur content of about 1.0% by weight. In other embodiments, the fine coal has an organic sulfur content of from about 0.8% to about 0.9% by weight.

Fine coal in some embodiments may be suitable for use as coking coal, i.e., sintering coal, and has a total sulfur content of less than 0.8% by weight. Fine coal in other embodiments may be suitable for use as steam coal and has a total sulfur content of from about 0.3% to about 4.5% by weight.

In embodiments, the fine coal has a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 28% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 1000 μm or less. In embodiments, the fine coal has a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 28% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In some embodiments, the fine coal has a total sulfur content of about 0.3% to about 2% by weight, an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In further embodiments, the fine coal has a total sulfur content of about 0.8% to about 1.3% by weight, an ash content of about 7% to about 10% by weight, a BTU heat content of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of 100 mesh or less, wherein about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

In embodiments, the fine coal has a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a total sulfur content of about 0.3% to about 2% by weight, an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of about 30 μm to about 150 μm. In additional embodiments, the fine coal has a total sulfur content of from about 0.8% to about 1.3% by weight, an ash content of from about 7% to about 10% by weight, a heat content in BTUs of from about 14,000 to about 16,000, a water content of from about 5% to about 10% by weight, and a particle size of from about 30 μm to about 50 μm.

The fine coal in embodiments has a volatile content of about 7% to about 37% by weight. The fine coal in certain embodiments has a volatile content of about 7% to about 25% by weight. The fine coal in some embodiments has a volatile content of about 10% to about 25% by weight. The fine coal in further embodiments has a volatile content of about 10% to about 20% by weight. The fine coal in some embodiments has a volatile content of about 15% to about 20% by weight. The fine coal in further embodiments has a volatile content of about 17% by weight. The fine coal in yet other embodiments is suitable for use as a coking coal, i.e., sintering coal and has a volatile matter content of from about 15% to about 37% by weight.

In embodiments, the fine coal has a volatile matter content of about 7% to about 37% by weight, a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 28% by weight, a heat content in BTUs of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 1000 microns or less. In embodiments, the fine coal has a volatile matter content of about 7% to about 37% by weight, a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 28% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In some embodiments, the fine coal has a volatile matter content of about 10% to about 25% by weight, a total sulfur content of about 0.3% to about 2% by weight, an ash content of about 3% to about 15% by weight, a BTU heat content of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In additional embodiments, the fine coal has a volatile matter content of about 15% to about 20% by weight, a total sulfur content of about 0.8% to about 1.3% by weight, an ash content of about 7% to about 10% by weight, a heat content in BTUs of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of 100 mesh or less, wherein about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

Fine coal in particular embodiments has a volatile content of about 7% to about 53% by weight. Fine coal in certain embodiments has a volatile content of about 7% to about 45% by weight. In embodiments, the fine coal has a volatile content of about 7% to about 37% by weight, a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 28% by weight, a heat content in BTUs of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of about 30 μm to about 150 μm. In some embodiments, the fine coal has a volatile matter content of about 10% to about 25% by weight, a total sulfur content of about 0.3% to about 2% by weight, an ash content of about 3% to about 15% by weight, a heat content in BTUs of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of about 30 μm to about 150 μm. In additional embodiments, the fine coal has a volatile matter content of about 15% to about 20% by weight, a total sulfur content of about 0.8% to about 1.3% by weight, an ash content of about 7% to about 10% by weight, a heat content in BTUs of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of about 30 μm to about 150 μm.

In embodiments, the finely divided coal has a carbon content of about 80% to about 95% by weight. In further embodiments, the finely divided coal has a carbon content of about 80% to about 92% by weight. In particular embodiments, the finely divided coal has a carbon content of about 80% to about 85% by weight. In other embodiments, the finely divided coal has a carbon content of about 80% by weight. Elemental analysis of carbon and other elements can be performed using known methods, including ASTM D-5373-02.

In some embodiments, the fine coal has a carbon content of about 40% to about 95% by weight. In certain embodiments, the fine coal has a carbon content of about 65% to about 95% by weight. In some embodiments, the fine coal has a carbon content of about 75% to about 95% by weight. In embodiments, the fine coal has a carbon content of about 80% to about 95% by weight, a volatile matter content of about 7% to about 37% by weight, a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 15% by weight, a heat content in BTUs of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In additional embodiments, the fine coal has a carbon content of about 80% to about 85% by weight, a volatile content of about 15% to about 20% by weight, a total sulfur content of about 0.8% to about 1.3% by weight, an ash content of about 7% to about 10% by weight, a heat content in BTUs of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of 100 mesh or less, wherein about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

Typically, the fine coal may have an oxygen content of 20% or less by weight. The fine coal in some embodiments has an oxygen content of about 0.5% to about 18% by weight. The fine coal in other embodiments has an oxygen content of about 0.5% to about 12% by weight. The fine coal in some embodiments has an oxygen content of about 0.5% to about 8% by weight. The fine coal in some embodiments has an oxygen content of about 0.5% to about 5% by weight. The fine coal in particular embodiments has an oxygen content of about 0.5% to about 2% by weight. The fine coal in embodiments has an oxygen content of about 5% to about 1.5% by weight. The fine coal in further embodiments has an oxygen content of about 1.0% to about 1.5% by weight. Without wishing to be bound by any particular theory, it is believed that an oxygen content of about 2% or less by weight is beneficial because oxidation on the surface of the fine coal can affect CO production, which is important in some manufacturing processes, including the steelmaking methods proposed in the present application.

In embodiments, the finely divided coal has an oxygen content of about 0.5% to about 1.5% by weight, a volatile matter content of about 7% to about 37% by weight, a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 15% by weight, a heat content in BTUs of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 1000 microns or less. In embodiments, the fine coal has an oxygen content of about 0.5% to about 1.5% by weight, a volatile content of about 7% to about 37% by weight, a total sulfur content of about 0.3% to about 4.5% by weight, an ash content of about 3% to about 15% by weight, a heat content in BTUs of about 12,000 to about 16,000, a water content of about 5% to about 15% by weight, and a particle size of 100 mesh or less. In additional embodiments, the fine coal has an oxygen content of about 1.0% to about 1.5% by weight, a volatile content of about 15% to about 20% by weight, a total sulfur content of about 0.8% to about 1.3% by weight, an ash content of about 7% to about 10% by weight, a heat content in BTUs of about 14,000 to about 16,000, a water content of about 5% to about 10% by weight, and a particle size of 100 mesh or less, wherein about 40% to about 60% by weight of the fine coal is retained by 325 mesh cells.

Mixtures

In another aspect, mixtures are provided that contain fine coal and at least one other type of coal. The fine coal and at least one other type of coal can be mixed using any methods known in the art. For example, the mixture can be obtained by depositing alternating portions of fine coal and at least one other type of coal in a container. The mixtures can be used for PSU as a caking coal, i.e., coking coal, or steam coal. The mixture in some embodiments is homogeneous. The mixture in other embodiments is not homogeneous. The at least one other type of coal and the amounts of each component in the mixtures can be selected to provide a mixture with one or more desired characteristics, financial optimization of coal purchases, elimination of one or more disadvantages of at least one of the components of the coal, or a combination thereof. The desired characteristics can depend on the intended use of the mixtures.

For example, at least one other type of coal can be selected to provide a mixture with a desired amount or percentage of water, ash, sulfur, volatiles, carbon, oxygen, or a combination thereof. As another example, at least one other type of coal having a volatile content of about 30% by weight can be mixed with a certain amount of fine coal having a volatile content of about 17% by weight to obtain a mixture having a volatile content of less than 30% by weight. The at least one other type of coal can be selected to form a mixture suitable for PSU or for use as steam coal or coking coal, i.e., caking coal. The mixture suitable for PSU can be a mixture that does not allow excessive formation of coke residue.

Fine coal or mixtures may be associated with sludge during storage and transportation. As used herein, the term "sludge" refers to any spent grains, sediment, or combination thereof, obtained, for example, during beverage production. As used herein, the phrase "associated with sludge" refers to mixing with sludge, coating with sludge, or a combination thereof, at least a portion of fine coal or a mixture comprising fine coal and at least one other type of coal.

Agglomerates

In another aspect, fine coal or mixtures containing fine coal and at least one other type of coal can be used to form an agglomerate or a portion of an agglomerate. Agglomerates in some embodiments include fine coal and at least one type of ore. Agglomerates in other embodiments include at least one type of ore and a mixture containing fine coal and at least one other type of ore. The ore of the agglomerates can be any metal ore, such as iron ore. The agglomerates can be formed using any methods known in the art. The agglomerates can be added to a blast furnace, for example, during iron or steel production.

The present application provides fine coal. In embodiments, the fine coal has a particle size of 1000 microns or less and a water content of about 5% to about 20% by weight. In some embodiments, the water content is from about 5% to about 15% by weight; from about 5% to about 10% by weight; from about 5% to about 7% by weight; from about 6% to about 9% by weight; about 8% by weight; or about 7% by weight. The fine coal can have a particle size of 100 mesh or less. The fine coal can have a particle size in which from about 40% to about 60% by weight, or about 50% by weight, of the fine coal is retained by 325 mesh cells. The fine coal may have a particle size of 325 mesh or less. The fine coal may have a BTU heat content of from about 12,000 to about 16,000; from about 12,400 to about 14,000; from about 12,800 to about 16,000; from about 13,500 to about 16,000; from about 14,000 to about 16,000; from about 15,000 to about 16,000; about 12,500; about 13,500; about 14,000; or about 15,500. The fine coal may have a total sulfur content of from about 0.3% to about 4.5% by weight; from about 0.6% to about 1.3% by weight; from about 0.8% to about 1.3% by weight; from about 0.8% to about 0.9% by weight; about 1.0% by weight; or less than about 0.8% by weight. The fine coal may have an ash content of from about 3% to about 28% by weight; from about 3% to about 15% by weight; from about 3% to about 10% by weight; from about 5% to about 10% by weight; from about 6% to about 8% by weight; or less than 6% by weight. The fine coal may have a volatile matter content of from about 7% to about 37% by weight; from about 15% to about 37% by weight; from about 7% to about 25% by weight; from about 10% to about 25% by weight; from about 10% to about 20% by weight; from about 15% to about 20% by weight; or about 17% by weight. The fine coal may have a volatile matter content of from about 7% to about 53% by weight; or from about 7% to about 45% by weight. In some embodiments, the carbon content is from about 40% to about 95% by weight; from about 65% to about 95% by weight; from about 75% to about 95% by weight; from about 80% to about 95% by weight; from about 80% to about 92% by weight; or from about 80% to about 85% by weight. The fine coal may have an oxygen content of 2% or less by weight. In some embodiments, the oxygen content is from about 0.5% to about 18% by weight; from about 0.5% to about 12% by weight; from about 0.5% to about 8% by weight; from about 0.5% to about 5% by weight; about 2% by weight; or from about 0.5% to about 1.5% by weight. The fine coal may have a particle size of from about 30 μm to about 1000 μm; from about 30 μm to about 900 μm; from about 30 μm to about 800 μm; from about 30 μm to about 700 μm; from about 30 μm to about 600 μm; from about 30 μm to about 500 μm; from about 30 μm to about 400 μm; from about 30 μm to about 300 μm; from about 30 μm to about 200 μm; from about 30 μm to about 150 μm; from about 30 μm to about 125 μm; from about 30 μm to about 100 μm; from about 30 μm to about 75 μm; from about 30 μm to about 50 μm; or about 44 μm.

Methods of obtaining coke

In another aspect, methods for producing coke are provided. In embodiments, the method includes heating, in the absence of air, fine coal or a mixture comprising fine coal and at least one other type of coal, for a time and at a temperature sufficient to convert the fine coal or mixture into coke. In particular embodiments, the fine coal has a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight.

In general, fine coal or mixtures containing fine coal and at least one other type of coal can be converted into coke using methods known in the art. For the coke making processes proposed in the present application, the fine coal or mixture containing fine coal and at least one other type of coal, in embodiments, has a water content of from about 5% to about 10% by weight, an ash content of less than 10% by weight, a volatile matter content of from about 15% to about 37% by weight, a sulfur content of less than about 1.0% by weight, and a fixed carbon content of from about 60% to about 74% by weight. For the coke making processes provided herein, the fine coal or mixture comprising the fine coal and at least one other type of coal, in some embodiments, has a water content of from about 5% to about 7% by weight, an ash content of less than about 8% by weight, a volatile matter content of from about 15% to about 25% by weight, a sulfur content of less than about 0.8% by weight, and a fixed carbon content of from about 60% to about 74% by weight.

Methods for producing coke are provided. In embodiments, methods for producing coke include heating, in the absence of air, fine coal or a mixture comprising fine coal and at least one other type of coal, for a time and at a temperature sufficient to convert the fine coal or mixture into coke, wherein the fine coal has a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight. The fine coal can have a water content of about 5% to about 10% by weight, an ash content of less than 10% by weight, a volatile matter content of about 15% to about 37% by weight, a sulfur content of less than about 1.0% by weight, and a fixed carbon content of about 60% to about 74% by weight. The fine coal may have a water content of about 5% to about 7% by weight, an ash content of less than 8% by weight, a volatile content of about 15% to about 25% by weight, a sulfur content of less than about 0.8% by weight, and a fixed carbon content of about 60% to about 74% by weight. The fine coal may have a particle size of 100 mesh or less; or a particle size of 325 mesh or less.

Methods of obtaining steel

In another aspect, the invention provides methods for producing steel based in part on the fine coal described herein. The fine coal or a mixture comprising the fine coal and at least one other type of coal is, in embodiments, used for the CIP in the steelmaking processes proposed in this application. That is, the fine coal or mixture can be used in any of the coal injection processes known in the art. In one embodiment, a method for producing steel includes injecting the fine coal described herein or a mixture comprising the fine coal and at least one other type of coal into a blast furnace containing coke and iron ore. In particular embodiments, the fine coal used for the CIP has a particle size of 1000 μm or less and a water content of from about 5% to about 20% by weight. In a further embodiment, the fine coal used for the PSU has a particle size of 200 mesh or less and a water content of about 5% to about 20% by weight. In another embodiment, the fine coal used for the PSU has a particle size of 200 mesh or less and a water content of about 8% to about 10% by weight.

In a particular embodiment, the fine coal or mixture replaces up to 40% of the coke required in standard steelmaking processes without pulverized coal injection. In one embodiment, the steelmaking processes presented herein achieve specific coke consumption rates of from about 275 kg/ton of liquid iron to about 325 kg/ton of liquid iron at injection rates of from about 175 kg/ton of liquid iron to about 225 kg/ton of liquid iron of fine coal or a mixture comprising fine coal and at least one other type of coal. In another embodiment, the steelmaking processes provided herein achieve a specific coke consumption of about 290 kg/ton of liquid iron to about 310 kg/ton of liquid iron at injection levels of about 190 kg/ton of liquid iron to about 210 kg/ton of liquid iron of fine coal or a mixture comprising fine coal and at least one other type of coal. In a further embodiment, the steelmaking processes provided herein achieve a specific coke consumption of about 300 kg/ton of liquid iron at injection levels of about 200 kg/ton of liquid iron of fine coal or a mixture comprising fine coal and at least one other type of coal.

In embodiments, fine coal or a mixture comprising fine coal and at least one other type of coal is injected in equal amounts through all tuyeres of the blast furnace.

In embodiments, the replacement ratio of the fine coal or the mixture comprising the fine coal and at least one other type of coal is from about 0.7 to about 0.9 kg of fine coal or the mixture per kg of coke. In other embodiments, the replacement ratio of the fine coal or the mixture comprising the fine coal and at least one other type of coal is from about 0.8 to about 0.9 kg of fine coal or the mixture per kg of coke. In further embodiments, the replacement ratio of the fine coal or the mixture comprising the fine coal and at least one other type of coal is about 0.85 kg of fine coal or the mixture per kg of coke. The replacement ratio of the fine coal or the mixture can be calculated using the mass-heat balance of the furnace and the chemical composition of the fine coal or the mixture.

Where appropriate, ASTM standard procedures were used to analyze fine coal for the characteristics presented in this document.

The present application provides methods for producing iron or steel. In embodiments, the methods for producing iron or steel include injecting fine coal or a mixture comprising fine coal and at least one other type of coal into a blast furnace containing coke and iron ore, wherein the fine coal has a particle size of 1000 μm or less and a water content of about 5% to about 20% by weight. The fine coal may have a particle size of 100 mesh or less and a water content of about 5% to about 20% by weight. The fine coal may have a particle size of 100 mesh or less and a water content of about 8% to about 10% by weight. The fine coal or mixture may replace up to 40% of the coke required in standard steelmaking procedures without pulverized coal injection. In a blast furnace, a specific coke consumption of about 275 kg/ton of hot metal to about 325 kg/ton of hot metal can be achieved at injection levels of about 175 kg/ton of hot metal to about 225 kg/ton of hot metal of fine coal or a mixture containing fine coal and at least one other type of coal. In a blast furnace, a specific coke consumption of about 290 kg/ton of hot metal to about 310 kg/ton of hot metal can be achieved at injection levels of about 190 kg/ton of hot metal to about 210 kg/ton of hot metal of fine coal or a mixture containing fine coal and at least one other type of coal. The blast furnace may achieve a specific coke consumption of about 300 kg/ton of hot metal at injection rates of about 200 kg/ton of hot metal, fine coal, or a mixture comprising fine coal and at least one other type of coal. The fine coal or mixture may be injected in equal amounts through all tuyeres of the blast furnace. The replacement ratio of the fine coal or mixture comprising fine coal and at least one other type of coal may be from about 0.7 to about 0.9 kg of fine coal or mixture per kg of coke; from about 0.8 to about 0.9 kg of fine coal or mixture per kg of coke; or about 0.85 kg of fine coal or mixture per kg of coke. The fine coal may have a particle size of 100 mesh or less; or a particle size of 325 mesh or less.

It should be understood that the various features, properties and functions disclosed above and others, or alternatives thereof, may be combined as desired in many other different products, methods, systems, devices or applications within the scope of the appended claims. Various unforeseen or currently unforeseen alternatives, modifications, changes or improvements may subsequently be made by those skilled in the art, which are also within the scope of the appended claims.

Claims (23)

1. A method for collecting fine coal comprising the following: dewatering a suspension of liquid waste of enriched coal having a solids content of from about 3% to about 20% by weight, to produce fine coal having: (i) particle size of 1000 µm or less, and (ii) an ash content of from about 3% to about 28% by weight; wherein dewatering the slurry of liquid waste of enriched coal comprises centrifuging the slurry in a solid rotor centrifuge, wherein the centrifuge comprises a rotating rotor, an internal screw and an overflow partition, and adjusting, based on (i) the properties of the slurry of liquid waste of the cleaned coal, (ii) the properties of the finely dispersed coal, or (iii) both, at least one parameter selected from the group consisting of the centrifugal torque, the difference in rotational speeds between the rotating rotor and the internal screw, and the overflow height of the overflow partition. 2. The method of claim 1, wherein the slurry of liquid clean coal waste has a solids content of from about 3% to about 17% by weight. 3. The method of claim 1, wherein the finely dispersed coal has an ash content of from about 3% to about 15% by weight. 4. The method of claim 1, wherein the finely dispersed coal has an ash content of from about 5% to about 10% by weight. 5. The method according to claim 1, wherein the finely dispersed coal has an ash content of less than 6% by weight. 6. The method of claim 1, wherein the particle size of the fine coal is 100 mesh or less. 7. The method of claim 1, wherein the particle size of the finely dispersed coal is from about 30 μm to about 150 μm. 8. The method according to claim 1, wherein the dewatering step occurs in the coal enrichment circuit of the coal preparation and enrichment plant. 9. The method of claim 1, wherein the dewatering step occurs downstream of the preparation and beneficiation, wherein fine coal having a particle size of 325 mesh or less is not collected. 10. The method of claim 1, wherein the dewatering step occurs upstream of the preparation and beneficiation step, which collects fine coal having a particle size of 325 mesh or less. 11. The method of claim 1, wherein the finely divided coal has a heat content in BTU (British thermal unit/pound) of from about 12,000 to about 16,000. 12. The method of claim 1, wherein the finely divided coal has a heat content in BTUs of from about 15,000 to about 16,000. 13. The method of claim 1, wherein the finely divided coal has a total sulfur content of from about 0.3% to about 4.5% by weight. 14. The method according to claim 1, wherein the finely dispersed coal has a total sulfur content of less than 0.8% by weight. 15. The method of claim 1, wherein the finely divided coal has a volatile matter content of from about 7% to about 37% by weight. 16. The method of claim 1, wherein the finely dispersed coal has a volatile matter content of from about 15% to about 20% by weight. 17. The method of claim 1, wherein the finely dispersed coal has an oxygen content of approximately 20% or less by weight. 18. The method of claim 1, wherein the finely dispersed coal has an oxygen content of approximately 2% or less by weight.