CN103571511A - Powder coal dry distillation method and device - Google Patents

Abstract

The invention discloses a powder coal dry distillation method and device, and aims to solve the problems that the technical process is, the circulation amount of the solid heat carrier is high, the gas heat carrier needs to be delivered by a gas compressor and the like in the existing powder coal dry distillation technique. The dry distillation method comprises the following steps: A. a powder coal raw material (2), and a high-temperature solid heat carrier and a high-temperature oxygen-free flue gas from a tubular charcoal burner (7) are mixed in a mixing heat transfer region to perform contact heat transfer, and are subject to dry distillation reaction; B. after entrained oil gas is stripped out from semicoke formed in the step A in a stripping section (17), part of the semicoke is cooled and discharged out of the dry distillation device, and the other part enters the tubular charcoal burner; and C. the semicoke entering the tubular charcoal burner contacts charcoal burning air to perform charcoal burning, thereby generating the high-temperature solid heat carrier and high-temperature oxygen-free flue gas. The invention also discloses a powder coal dry distillation device for implementing the dry distillation method. The method and device can be used for dry distillation processing of various types of powder coal.

Description

Dry distillation method and device for pulverized coal

technical field

The invention belongs to the technical field of pulverized coal dry distillation, and relates to a pulverized coal dry distillation method and device.

Background technique

With the increasing scarcity of world oil resources and the advent of the era of high oil prices, the use of coal dry distillation technology to produce coal tar has become an important plan to replace and supplement oil resources. The products of coal dry distillation are semi-coke, oil and gas (mainly coal tar and liquefied gas) and coal gas; the yield and composition of coal dry distillation products depend on the properties of raw coal and processing conditions (mainly temperature and time).

The pulverized coal dry distillation method introduced in the article "Lignite Solid Heat Carrier Dry Distillation New Technology Industrial Test" published in the first issue of February 1995 in the "Journal of Dalian University of Technology" is to crush the raw coal to less than 6mm and use it in the drying riser. After the hot flue gas is lifted and heated and dried, the dry coal is put into the dry coal storage tank, and then goes to the mixer through the feeder. The 800°C hot coke powder from the hot semi-coke storage tank is mixed with dry coal in the mixer, and the temperature of the mixed material is 550-650°C; then it enters the reactor to complete the rapid pyrolysis reaction of coal and precipitate dry distillation gaseous products. Coal or semi-coke powder is burned in the fluidized combustion furnace to generate oxygen-containing flue gas at 800-900 °C, which is partially combusted with the 600 °C semi-coke from the reactor at the lower part of the heating riser and heated and lifted to the hot semi-coke storage tank; The coke powder is heated to 800-850°C and recycled as a heat carrier (solid). The hot flue gas from the hot semi-coke storage tank goes to dry the riser. Part of the coke powder is exported from the product semi-coke tube in the lower part of the reactor, and after cooling, it is shipped as a semi-coke product. The problems in the above method are: 1. The oxygen-containing flue gas produced by the fluidized combustion furnace is partially combusted with the semi-coke from the reactor in the heating riser, and the semi-coke is heated and lifted to the hot semi-coke storage tank, and the hot coke powder is then From the hot semi-coke storage tank, it enters the mixer and mixes with dry coal, and after mixing, it enters the reactor for reaction; this makes the process more complicated. ②Use only hot coke powder as a solid heat carrier to heat dry coal, so that the circulation of solid heat carrier is large, which will reduce the production capacity of semi-coke products; a large amount of hot coke powder is generated, and the energy consumption is also high.

Chinese patent CN101328415A discloses a piston-type fluidized bed low-temperature dry distillation process, using the riser fluid catalytic cracking device principle, using the riser reactor as the dry distillation reactor, using the catalyst regenerator as the high-temperature water gas generator, and using the high-temperature water gas It is the fluidized medium and heat carrier of dry distillation raw material. The dry distillation raw material is transported to the riser fluidized bed reactor for dry distillation reaction, and oil and gas are separated after the reaction to obtain dry distillation products. The dry distillation semi-coke enters the water gas generator, and the carbon in the dry distillation semi-coke, oxygen in the air and water vapor are oxidized and reacted with water gas to obtain water gas. The existing problem is that the high-temperature water gas used as the fluidized medium and heat carrier of carbonization raw material needs to be transported from the water gas generator to the riser carbonization reactor by a gas compressor. The delivery of high-temperature water gas will put forward higher material requirements for the gas compressor; in addition, the gas compressor is always in a high and harsh operating state, which will affect the long-term operation of the retort device.

Contents of the invention

The object of the present invention is to provide a method and device for dry distillation of pulverized coal, so as to solve the problems of complex process, large circulation of solid heat carrier, and gas compressor required for gas heat carrier. transportation and other issues.

In order to solve the above problems, the technical solution adopted in the present invention is:

A dry distillation method of pulverized coal, characterized in that: the method comprises the following steps in sequence:

A. The pulverized coal raw material enters the dry distillation reactor through the pulverized coal raw material feed pipe, and the high-temperature solid heat carrier and oxygen-free flue gas from the tubular charcoal burner enter the dry distillation reactor. The pulverized coal raw material, high-temperature solid heat carrier and oxygen-free fume The gas is mixed and contacted for heat transfer in the mixing heat transfer area in the carbonization reactor, and then the pulverized coal raw material undergoes carbonization reaction in the dense phase bed of the carbonization reactor to generate water vapor, oil gas, coal gas and solid products, and the dense phase of the carbonization reactor The pulverized coal carbonization solid product in the bed is mixed with the solid heat carrier to form semi-coke. The gas in the carbonization reactor is separated from the semi-coke by the cyclone separator installed in the carbonization reactor, and then flows out of the carbonization reactor. The carbonization reactor is densely packed. The semi-coke in the phase bed flows downwards and enters the stripping section located below the dry distillation reactor;

B. Introduce stripping steam into the stripping section to strip out the oil and gas entrained in the semi-coke, and the semi-coke stripped in the stripping section flows to the lower part of the stripping section, and part of it is discharged from the carbonization device after being cooled by heat extraction , and the other part enters the lower part of the tubular charcoal burner through the semi-coke conveying pipe;

C. The semi-coke entering the tubular charcoal burner is in contact with the charcoal-burning air introduced from the bottom of the tubular charcoal burner, and burns charcoal along the tube-type charcoal burner to generate high-temperature solid heat carrier and oxygen-free flue gas. The high-temperature solid heat carrier and oxygen-free flue gas enter the carbonization reactor and are mixed with pulverized coal raw materials.

The pulverized coal carbonization device used to realize the above method includes a carbonization reactor and a heat carrier generation device, and is characterized in that the carbonization reactor is a bed-type fluidized bed carbonization reactor, and the heat carrier generation device is coaxial with the carbonization reactor A tubular charcoal burner is provided, and the dry distillation reactor is provided with a pulverized coal raw material feed pipe, and a stripping section is arranged coaxially below the dry distillation reactor. The tubular charcoal burner passes through the stripping section, and its top outlet is located at Above the dense-phase bed interface of the dry distillation reactor, below the outlet of the pulverized coal raw material feed pipe, the lower part of the stripping section is provided with a semi-coke discharge pipe and a semi-coke delivery pipe, and the outlet of the semi-coke discharge pipe is connected to the heat collector , The heat collector is connected to the semi-coke discharge tank through a pipeline, the outlet of the semi-coke delivery pipe is connected to the lower part of the tubular charcoal burner, and the bottom of the tubular charcoal burner is provided with a charcoal air distributor.

The present invention adopts the fluidized bed technology to carry out pulverized coal dry distillation; Adopt the present invention, have the following beneficial effects: (1) semi-coke burns charcoal in the tubular charcoal burner, and the high-temperature solid heat carrier and high-temperature anaerobic flue gas generated enter Dry distillation reactor, the pulverized coal raw material enters the dry distillation reactor through the pulverized coal raw material feed pipe, and is directly mixed with the above-mentioned high-temperature solid heat carrier and high-temperature anaerobic flue gas in the dry distillation reactor for contact heat transfer, and then in the dry distillation reactor The carbonization reaction is carried out in the dense phase bed, the carbonization process is relatively simple, and the structure of the carbonization device is also relatively simple. (2) Use the high-temperature solid heat carrier from the tubular charcoal burner and the high-temperature anaerobic flue gas to heat the pulverized coal raw material, and the heat carried by the anaerobic flue gas can be effectively used, thereby reducing the amount of solid heat carrier and the circulation amount , increase the production capacity of semi-coke products with higher value, and improve economic benefits. (3) Since the amount of solid heat carrier is less, the energy consumption of generating high-temperature solid heat carrier can be reduced (including reducing the amount of charcoal-burning air). The charcoal burning load of the tubular charcoal burner is low, and its structure size and investment can be reduced; the charcoal burning temperature is easy to control, which can prevent over-temperature damage. The present invention uses a tubular charcoal burner, which has stronger charcoal burning capability and better operating flexibility. (4) The amount of high-temperature solid heat carrier is less, and its mixing ratio with pulverized coal raw material is low (the ratio of the weight flow rate of high-temperature solid heat carrier entering the carbonization reactor to the pulverized coal raw material is generally 2.5 to 3.5), so that it can Increase the coke content of the discharged semi-coke, thereby increasing the further utilization value of the semi-coke product. (5) The high-temperature anaerobic flue gas generated by burning charcoal in the tubular charcoal burner flows out from the outlet of the tubular charcoal burner, and directly enters the carbonization reactor to heat the pulverized coal raw material together with the high-temperature solid heat carrier. Therefore, the present invention does not need to use a gas compressor to transport high-temperature oxygen-free flue gas, there is no problem of higher material requirements for the gas compressor, and there is no problem that the gas compressor is always in a high and harsh operating state, which affects the long-term operation of the retort device The problem.

The invention can be used for dry distillation processing of various pulverized coals, and is especially suitable for dry distillation processing of low-quality coal (such as lignite) pulverized coals. The dry distillation process can be carried out continuously and stably, and the adjustment is flexible; the pulverized coal raw material can be processed in a large amount, and the coal tar yield is high.

The present invention will be further described in detail below in conjunction with the accompanying drawings, specific embodiments and examples. The drawings, specific implementations and examples do not limit the scope of protection claimed by the present invention.

Description of drawings

Fig. 1 is a schematic diagram of a pulverized coal dry distillation device of the present invention.

Detailed ways

Referring to FIG. 1 , the pulverized coal carbonization device (referred to as the carbonization device for short) of the present invention includes a carbonization reactor 5 and a heat carrier generation device. The dry distillation reactor 5 is a bed-type fluidized bed dry distillation reactor, and the heat carrier generating device is a tubular charcoal burner 7 arranged coaxially with the dry distillation reactor 5 . The shell of the dry distillation reactor 5 is mainly composed of a cylindrical metal cylinder on the upper part and an inverted conical metal cylinder on the lower part, and is lined with a heat-insulating and wear-resistant lining (not shown). The dry distillation reactor 5 is provided with a cyclone separator; the cyclone separator shown in Figure 1 is a first cyclone separator 181 and a second cyclone separator 182 installed in series, and the material legs of the two cyclone separators extend into the dry distillation In the dense-phase bed 6 of the reactor (extending to the upper part of the dense-phase bed 6 of the dry distillation reactor). The top of the dry distillation reactor 5 is provided with a gas collection chamber 1 and a gas outlet pipe 19 . The dry distillation reactor 5 is provided with a pulverized coal raw material feed pipe 3 .

A stripping section 17 is arranged coaxially below the dry distillation reactor 5 , and the top of the stripping section 17 is connected to the bottom of the dry distillation reactor 5 . The shell of the stripping section 17 is mainly composed of a cylindrical metal cylinder lined with a heat-insulating and wear-resistant lining (figure omitted). The stripping section 17 is provided with a stripping baffle (shown in FIG. 1 as a herringbone stripping baffle) and a stripping steam distributor 80 . The tubular charcoal burner 7 passes through the stripping section 17 , and its top outlet is located above the dense-phase bed interface 60 of the dry distillation reactor and below the outlet of the pulverized coal raw material feed pipe 3 . The overall structure of dry distillation reactor 5-stripping section 17-tubular charcoal burner 7 shown in Figure 1 is similar to that of a coaxial internal riser fluid catalytic cracking (FCC) device for petroleum processing.

The lower part of the stripping section 17 is provided with a semi-coke discharge pipe 16 and a semi-coke delivery pipe 9, on which are provided a semi-coke flow control valve 10 to control the flow of semi-coke in the pipe. In Fig. 1, the inlet of semi-coke discharge pipe 16 is connected to the bottom of stripping section 17, and the outlet is connected to the bottom of heat extractor 14; the top of heat extractor 14 is connected to the top of semi-coke discharge tank 13 through pipeline 15 . The heat extractor 14 can use various FCC external heat extractors, and the heat extractor 21 generally uses desalted water at ambient temperature (needs above zero). The semi-coke discharge tank 13 is a metal container.

The outlet of the semi-coke delivery pipe 9 is connected to the bottom of the tubular charcoal burner 7 . The bottom of the tubular charcoal burner 7 is provided with a charcoal burner air distributor 11, and the charcoal burner air distributor 11 is located below the interface where the outlet of the semi-coke delivery pipe 9 is connected to the tubular charcoal burner 7. The overall structure of the tubular charcoal burner 7 shown in Fig. 1 is similar to that of the FCC riser reactor. The tubular charcoal burner 7 is made of a metal tube with a circular cross section, and is lined with a heat-insulating and wear-resistant lining (figure omitted); the vertical height (from top to bottom) is generally 10-40m, and the inner diameter is generally 400-400m. 5000mm.

In Fig. 1, a baffle plate 4 is provided above the top outlet of the tubular charcoal burner 7, which prevents the pulverized coal raw material 2 from rushing directly to the top of the tubular charcoal burner 7 after flowing out from the outlet of the pulverized coal raw material feed pipe 3 outlet, causing the outlet pressure of the tubular charcoal burner 7 to increase. The baffle plate 4 is generally conical (as shown in FIG. 1 ) or circular plane (not shown in the figure), and is fixed on the top of the tubular charcoal burner 7 by a metal rod. When the baffle plate 4 is conical, the cone apex angle α (as shown in FIG. 1 ) is generally 60-90 degrees.

In FIG. 1 , the pulverized coal raw material feeding pipe 3 is composed of a horizontal pipe section and a vertical pipe section, and the horizontal pipe section is fixed on the cylindrical body at the upper part of the dry distillation reactor 5 . The outlet of the pulverized coal raw material feed pipe 3 is located at the bottom of the vertical pipe section, the top outlet of the tubular charcoal burner 7 and the top of the baffle plate 4 . The vertical distance H from the outlet of the pulverized coal raw material feed pipe 3 to the top of the conical baffle 4, or to the upper surface of the circular planar baffle 4 (figure omitted), is generally 0.5-2.5m.

In Fig. 1, the semi-focus delivery pipe 9 is composed of a vertical pipe section and an inclined pipe section. The vertical pipe section (as a submerged flow pipe) extends into the stripping section 17 from the bottom of the stripping section 17, and the top inlet of the vertical pipe section is the entrance of the semi-coke delivery pipe 9, which is located at the bottom of the stripping section 17. The outlet of the inclined pipe section is the outlet of the semi-coke delivery pipe 9, which is connected with the lower part of the tubular charcoal burner 7.

Each pipeline in the retort device uses circular metal tubes with a heat-insulating and wear-resistant lining (figure omitted). The inner diameter of each pipeline is mainly determined according to the flow rate and density of the material and/or medium in each pipeline.

The semi-coke flow control valve 10 can use various commonly used flow control valves for controlling the flow of solid powder, such as a slide valve. The stripping steam distributor 80 and the charcoal-burning air distributor 11 can use a commonly used annular distributor or dendritic distributor.

Adopt the dry distillation device shown in Fig. 1 to carry out the method for pulverized coal dry distillation of the present invention (being called for short dry distillation method), comprise the following steps successively:

A. The pulverized coal raw material 2 enters the carbonization reactor 5 through the pulverized coal raw material feed pipe 3, and the high-temperature solid heat carrier and high-temperature anaerobic flue gas from the tubular charcoal burner 7 enter the carbonization reactor 5. The pulverized coal raw material 2 is mixed with the high-temperature solid heat carrier and the high-temperature anaerobic flue gas in the mixing heat transfer area in the carbonization reactor 5 and contacted for heat transfer, and then the pulverized coal raw material 2 is subjected to carbonization reaction in the dense-phase bed 6 of the carbonization reactor , to generate water vapor, oil gas, gas and solid products; the main components of gas are methane, carbon dioxide, carbon monoxide, hydrogen and so on. The above-mentioned mixing heat transfer area refers to the area between the horizontal section of the upper cylindrical body of the dry distillation reactor 5 where the outlet of the pulverized coal raw material feed pipe 3 is located and the dense phase bed interface 60 of the dry distillation reactor.

The pulverized coal dry distillation solid product in the dry distillation reactor dense-phase bed 6 is mixed with the solid heat carrier to form semi-coke. The gas 20 in the dry distillation reactor 5 enters the dilute phase section of the dry distillation reactor 5, and the semi-coke is separated by the first cyclone separator 181 and the second cyclone separator 182 arranged in the dry distillation reactor 5, and then enters the gas collection chamber 1, and then flow out from the top of the dry distillation reactor 5 through the gas outlet pipe 19. The gas 20 mainly includes the oxygen-free flue gas from the tubular charcoal burner 7 that enters the dry distillation reactor 5, and the water vapor, oil gas, Coal gas, as well as the stripping water vapor 81 after stripping the semi-coke in the stripping section 17 and the oil and gas entrained by the stripped semi-coke; the oil and gas are mainly coal tar and liquefied gas. The semi-coke after the stripping of the following step C will also generate a small amount of gas during the charcoal burning process in the tubular charcoal burner 7; The oxygen-free flue gas enters the dry distillation reactor 5 through the top outlet of the tubular charcoal burner 7, and is also included in the gas 20.

The semi-coke separated by the first cyclone separator 181 and the second cyclone separator 182 falls into the dense-phase bed 6 of the dry distillation reactor through the dipleg.

The semi-coke in the dense-phase bed 6 of the dry distillation reactor flows downwards and enters the stripping section 17 arranged below the dry distillation reactor 5 .

B. Pass the stripping steam 81 into the stripping section 17 through the stripping steam distributor 80 to strip off the oil and gas entrained in the semi-coke. The semi-coke stripped in the stripping section 17 flows to the lower part of the stripping section 17, part of which is discharged from the carbonization device after being cooled by heat extraction, and the other part enters the lower part of the tubular charcoal burner 7 through the semi-coke delivery pipe 9.

Referring to Fig. 1, a part of the stripped semi-coke enters the heat extractor 14 through the semi-coke discharge pipe 16, and is cooled by the heat-extracting medium 21 (usually to below 80°C). The semi-coke after heating and cooling enters the semi-coke discharge tank 13 through the pipeline 15, and finally the semi-coke discharge tank 13 is discharged from the carbonization device as a semi-coke product. The semi-coke product has a high coke content and can be used as a fuel for circulating fluidized bed boilers, or as a raw material for the production of synthesis gas for the synthesis of methanol.

In the present invention, the amount of part of the stripped semi-coke discharged from the carbonization device is determined according to the material balance calculation of the carbonization device.

C. The semi-coke entering the tubular charcoal burner 7 is in contact with the charcoal air 12 introduced from the charcoal air distributor 11 located at the bottom of the tubular charcoal burner 7, and burns along the tubular charcoal burner 7 upwards Charcoal burns off part of the coke on the semi-coke to generate high-temperature solid heat carrier and high-temperature anaerobic flue gas. The high-temperature solid heat carrier and high-temperature oxygen-free flue gas flow out from the top outlet of the tubular charcoal burner 7, change the flow direction through the conical baffle plate 4, and then enter the dry distillation reactor 5, where they are mixed with pulverized coal raw materials in the heat transfer area. 2 Mix and start step A again. The high-temperature heat carrier used for heating the pulverized coal raw material 2 in the mixed heat transfer area in the carbonization reactor 5 of the present invention is composed of the above-mentioned high-temperature solid heat carrier generated in the tubular charcoal burner 7 and high-temperature oxygen-free flue gas. The high-temperature solid heat carrier that flows out from the outlet of the tubular charcoal burner 7 is generated by burning charcoal from the semi-coke that enters the tubular charcoal burner 7. The present invention does not strictly limit the coke content of the high-temperature solid heat carrier. In the above-mentioned charcoal burning process, the remaining entrained oil and gas of the semi-coke after stripping are also burned.

The above steps A to C are carried out continuously and cyclically.

In step A, after the gas 20 in the dry distillation reactor 5 flows out from the dry distillation reactor 5, it enters the fractionation system and the absorption stabilization system for separation to obtain crude gas, liquefied gas and liquid coal tar. The crude gas in the present invention is mainly composed of gas generated by carbonization reaction in the dense-phase bed 6 of the carbonization reactor, oxygen-free flue gas and a small amount of gas generated by charcoal burning in the tubular charcoal burner 7 . After the crude gas and liquefied gas are desulfurized in a pressure swing adsorption device to remove nitrogen, and then desulfurized in a desulfurization device, coal gas and liquefied gas products are obtained; after liquid coal tar is desulfurized in a desulfurization device, liquid coal tar products are obtained. The above-mentioned process is commonly used in the field, and Embodiment 1 to Embodiment 6 are the same, and detailed description is omitted.

The above-mentioned coal gas and liquefied gas products can be used as civil fuels, and the coal gas products can also be used to further synthesize methanol or oil products. Liquid coal tar products can undergo secondary processing to produce vehicle fuel. For the composition and distribution of products obtained by the carbonization reaction of the present invention, refer to the examples of the present invention (the liquid coal tar product is referred to as coal tar for short in Examples 1 to 6).

The operating conditions of the dry distillation method of the present invention are generally as follows:

In step A, the ratio of the weight flow rate of the high-temperature solid heat carrier entering the carbonization reactor 5 to the pulverized coal raw material 2 is 2.5 to 3.5, and the weight flow rate of the high-temperature anaerobic flue gas entering the carbonization reactor 5 and the pulverized coal raw material 2 is The ratio is 0.13 to 0.15. The temperature after the high-temperature solid heat carrier and pulverized coal raw material 2 are mixed in the mixing heat transfer area in the carbonization reactor 5 (referring to the average temperature on the horizontal plane near the dense phase bed interface 60 of the carbonization reactor, examples 1 to 6 Same here) is 460～580℃. The temperature of the high-temperature solid heat carrier and high-temperature anaerobic flue gas entering the dry distillation reactor 5 is the temperature at the top outlet of the tubular charcoal burner 7, and the temperature of the pulverized coal raw material 2 entering the pulverized coal raw material feed pipe 3 is the ambient temperature.

In step A, the absolute pressure at the top of the carbonization reactor 5 is 0.1-0.35 MPa, the temperature of the dense-phase bed 6 in the carbonization reactor (ie, the carbonization reaction temperature) is 450-560° C. The dry distillation reaction time in the bed 6 is 2-10 minutes, and the gas linear velocity in the dilute phase section of the dry distillation reactor 5 is 0.3-0.9 m/s. The temperature of the dense-phase bed 6 of the dry distillation reactor refers to the average temperature of the dense-phase bed 6 of the dry distillation reactor. The dilute phase section of the carbonization reactor 5 refers to the section above the mixing heat transfer area in the carbonization reactor 5 . For the gas, refer to the description of the gas 20 above.

During operation, the dense-phase bed 6 of the carbonization reactor is in a state of fluidized expansion. The water vapor, oil gas, and coal gas generated by the carbonization reaction of the pulverized coal raw material 2 in the dense-phase bed 6 of the carbonization reactor, as well as the stripped water vapor 81 and the stripped semi-coke entrainment from the semi-coke stripped in the stripping section 17 The oil and gas can be used as the fluidization medium to make the dry distillation reactor dense-phase bed 6 in a fluidized expansion state.

The temperature of the dense-phase bed 6 in the carbonization reactor is preferably 480-540° C., and the carbonization reaction time of the pulverized coal raw material 2 in the dense-phase bed 6 of the carbonization reactor is preferably 3-6 minutes.

The temperature of the dense-phase bed 6 in the carbonization reactor is preferably 500-520° C., and the carbonization reaction time of the pulverized coal raw material 2 in the dense-phase bed 6 of the carbonization reactor is preferably 3.5-4.5 minutes.

The inner diameter of the upper cylindrical body of the carbonization reactor 5 is mainly calculated and determined according to the pulverized coal raw material handling capacity and the variation range of the gas linear velocity in the dilute phase section of the carbonization reactor 5, and the height of the dense phase bed 6 of the carbonization reactor is mainly determined according to the pulverized coal The carbonization reaction time of the raw material 2 in the dense-phase bed 6 of the carbonization reactor and the storage amount of semi-coke in the carbonization reactor 5 are calculated and determined, and the height of the dilute phase section of the carbonization reactor 5 is mainly determined based on the calculation of the sedimentation height of the semi-coke.

In step B, the temperature of the semi-coke bed in the stripping section 17 is 480-520°C. After the semi-coke entering the stripping section 17 is stripped, usually more than 95% of the entrained oil and gas can be stripped (the same as in Embodiment 1 to Embodiment 6). The coke content of the semi-coke stripped in the stripping section 17 is generally 75% to 85%.

In step C, the time for the semi-coke entering the tubular charcoal burner 7 to burn charcoal in the tubular charcoal burner 7 is 5～40s (s is second); the temperature at the outlet of the tubular charcoal burner 7 is 670-750°C, the absolute pressure is basically the same as the absolute pressure at the top of the carbonization reactor 5 . The average air linear velocity in the tubular charcoal burner 7 is 2～10m/s, and this average air linear velocity refers to the average linear velocity of the charcoal burning air 12 flowing upward after entering the tubular charcoal burner 7 (in the tubular charcoal burner 7 Calculated under the temperature and absolute pressure conditions at the outlet of the charcoal burner 7). The charcoal-burning air 12 is compressed air preheated to 120-180° C., and its absolute pressure is 0.25-0.4 MPa. According to the flow rate and the coke content of the stripped semi-coke that enters the tubular charcoal burner 7, the flow of the charcoal-burning air 12 that is passed into the tubular charcoal burner 7 through the charcoal-burning air distributor 11 can be made semi-coke. Coke exhausts the oxygen in the charcoal-burning air 12 during the charcoal-burning process, and high-temperature oxygen-free flue gas is obtained at the outlet of the tubular charcoal burner 7 . Anaerobic flue gas means flue gas substantially free of free oxygen. Regulating the flow rate of the charcoal-burning air 12 passing into the tubular charcoal burner 7 can also control the temperature at the outlet of the tubular charcoal burner 7 .

The vertical height of the tubular charcoal burner 7 is mainly calculated and determined according to its operating conditions and the total height of the carbonization reactor 5 and the stripping section 17, and the inner diameter is mainly determined according to the variation range of the average air velocity.

The pulverized coal raw material 2 used in the dry distillation method of the present invention is in the form of powder, the particle diameter is not greater than 5 mm, the water content is not higher than 45%, and the oil content is 5% to 25%. The water content and oil content are measured by the Gegging method (GB/T1341-2007 Gegging low-temperature carbonization test method for coal) (the same as in Embodiment 1 to Embodiment 6). Using the pulverized coal raw material 2 with a particle size not greater than 5mm can make the pulverized coal raw material 2 be able to be normally fluidized and carbonized in the bed type dry distillation reactor 5 to obtain a higher coal tar yield; The semi-coke in the tubular charcoal burner 7 is better fluidized, and the coke on the semi-coke burns better, thereby generating more heat.

By adopting the dry distillation device and the dry distillation method of the present invention, higher coal tar yield can be obtained; the actual obtained coal tar yield can reach 85%-105% of the oil content of pulverized coal raw material 2 measured by the Gejin method.

According to the instructions or requirements of the present invention, those skilled in the field of pulverized coal carbonization can select the carbonization operating conditions proposed in the present invention and select various equipment components to design, operate and control the carbonization device according to the specific operation conditions.

The ambient temperature in the present invention is -10-40°C, the pressure is absolute pressure, the percentages are weight percentages, and the inner diameter refers to the inner diameter of the metal cylinder or the heat-insulating and wear-resistant lining of the pipeline lining. In FIG. 1 , arrows without reference numerals indicate the flow directions of various materials and/or media.

Example

On the small-scale test device of the pulverized coal carbonization device shown in FIG. 1 , 6 groups of tests (Example 1 to Example 6) were carried out according to the steps of the pulverized coal carbonization method described in the specific embodiment section of this specification. The pulverized coal raw material 2 is Yima pulverized coal raw material, and its properties are shown in Table 1; the feed rate (the weight flow rate of the pulverized coal raw material 2 entering the pulverized coal raw material feed pipe 3) is 3kg/h (3 kg/hour).

In Examples 1 to 6, the temperature of the semi-coke bed in the stripping section 17 is 520°C, and the stripping medium is the stripping steam 81 at 520°C. The stripped semi-coke that enters the heat extractor 14 through the semi-coke discharge pipe 16 is cooled to 80° C. by heat extraction medium (de-salted water at ambient temperature). The absolute pressure at the outlet of the tubular charcoal burner 7 is basically the same as the absolute pressure at the top of the carbonization reactor 5. For the test ambient temperature of each embodiment, refer to the temperature of the pulverized coal raw material 2 in Table 2.

See Table 2 for the remaining operating conditions of Examples 1 to 6, and see Table 3 for product distribution and properties of some products. Some items in Table 3 are described as follows: ① Product distribution refers to the total product distribution of the dry distillation unit. ② Coal gas is roughly composed of 40% methane, 20% carbon dioxide, 10% carbon monoxide, and the balance of hydrogen, ethane and ethylene. ③The main components of liquefied petroleum gas are carbon 3 and carbon 4. ④ The stripping steam 81 passed into the stripping section 17 through the stripping steam distributor 80 is not included in the product distribution. 5. the oxygen in the charcoal-burning air 12 that enters the tubular charcoal-burning device 7 through the charcoal-burning air distributor 11 is included in the product distribution (in the form of carbon dioxide, carbon monoxide), and the nitrogen in the charcoal-burning air 12 is not included in the product distribution, Other very small amounts of gases in the charcoal-burning air 12 are not considered.

The property of table 1 pulverized coal raw material (embodiment 1～embodiment 6)

project data Bulk specific gravity (sedimentation state), g/ml 1.06 Specific heat, cal/kg·℃ 0.264 Oil content, % 12.5 Moisture content, % 20.5 Coal ash content (determined by combustion method), % 13.4 Particle size distribution,% Below 20μm 6.5 20～40μm 5.5 40～80μm 6.6 80～110μm 8.2 110～149μm 10.3 149～500μm 19.1 500～1000μm 15.0 1000～1500μm 13.3 1500～3000μm 9.2 3000～5000μm 6.3

The operating conditions of table 2 embodiment 1～6

The product distribution of table 3 embodiment 1～6 and the character of part product

Claims (9)

1. a method for destructive distillation for fine coal, is characterized in that: the method in turn includes the following steps:

A. fine coal raw material (2) enters dry distillation reactor device (5) through fine coal material feeding tube (3), from make charcoal high-temp solid thermal barrier and the anaerobic flue gas of device (7) of tubular type, enter dry distillation reactor device (5), fine coal raw material (2) mixes and transmission of heat by contact in the contact heat transfer region in dry distillation reactor device (5) with high-temp solid thermal barrier and anaerobic flue gas, fine coal raw material (2) carries out dry distillation reactor in dry distillation reactor device dense bed (6) afterwards, generate water vapor, oil gas, coal gas and solid product, fine coal destructive distillation solid product and solid thermal carriers in dry distillation reactor device dense bed (6) are mixed to form semicoke mutually, the cyclonic separator of gas (20) in dry distillation reactor device (5) in being located at dry distillation reactor device (5) isolated half and defocusedly by dry distillation reactor device (5), flowed out, semicoke in dry distillation reactor device dense bed (6) flows downward, enter the stripping stage (17) of being located at dry distillation reactor device (5) below,

B. in stripping stage (17), pass into water stripping steam (81), stripping goes out semicoke entrained oil gas, semicoke in stripping stage (17) after stripping flows to the bottom of stripping stage (17), a part is discharged destructive distillation device after heat-obtaining cooling, and another part enters the make charcoal bottom of device (7) of tubular type through semicoke transfer lime (9);

C. entering the air of making charcoal (12) passing into bottom the tubular type semicoke of making charcoal in device (7) and the device (7) of making charcoal from tubular type contacts, along tubular type up the making charcoal of device (7) of making charcoal, generate high-temp solid thermal barrier and anaerobic flue gas, high-temp solid thermal barrier and anaerobic flue gas enter in dry distillation reactor device (5), mix with fine coal raw material (2).

2. method according to claim 1, it is characterized in that: the ratio that enters the weight rate of the interior high-temp solid thermal barrier of dry distillation reactor device (5) and fine coal raw material (2) is 2.5～3.5, the ratio that enters the weight rate of the interior high temperature anaerobic flue gas of dry distillation reactor device (5) and fine coal raw material (2) is 0.13～0.15.

3. method according to claim 1 and 2, it is characterized in that: the absolute pressure at dry distillation reactor device (5) top is 0.1～0.35MPa, the temperature of dry distillation reactor device dense bed (6) is 450～560 ℃, the dry distillation reactor time of fine coal raw material (2) in dry distillation reactor device dense bed (6) is 2～10min, and the linear gas velocity of dry distillation reactor device (5) dilute phase section is 0.3～0.9m/s.

4. method according to claim 3, it is characterized in that: entering the time that semicoke that tubular type makes charcoal in device (7) makes charcoal in tubular type is made charcoal device (7) is 5～40s, the make charcoal temperature in device (7) exit of tubular type is 670～750 ℃, and the average air linear speed that tubular type is made charcoal in device (7) is 2～10m/s.

5. method according to claim 1 and 2, is characterized in that: the particle diameter of fine coal raw material (2) is not more than 5mm, and water content is not higher than 45%, and oleaginousness is 5%～25%.

6. one kind for realizing the fine coal destructive distillation device of method described in claim 1, comprise dry distillation reactor device (5), thermal barrier generating apparatus, it is characterized in that: dry distillation reactor device (5) is bed formula fluidized bed dry distillation reactor, thermal barrier generating apparatus for the tubular type of the coaxial setting of dry distillation reactor device (5) device (7) of making charcoal, dry distillation reactor device (5) is provided with fine coal material feeding tube (3), the below of dry distillation reactor device (5) is coaxially arranged with stripping stage (17) with it, tubular type is made charcoal device (7) through stripping stage (17), its top exit is positioned at the top at dry distillation reactor device dense bed interface (60), the below of fine coal material feeding tube (3) outlet, the bottom of stripping stage (17) is provided with semicoke drainage conduit (16) and semicoke transfer lime (9), the outlet of semicoke drainage conduit (16) is connected with heat collector (14), heat collector (14) is connected with semicoke blow-down drum (13) by pipeline (15), the make charcoal bottom of device (7) of the outlet of semicoke transfer lime (9) and tubular type is connected, the make charcoal bottom of device (7) of tubular type is provided with the air-distributor of making charcoal (11).

7. device according to claim 6, is characterized in that: the make charcoal top of device (7) top exit of tubular type is provided with baffle plate (4), and baffle plate (4) is cone surface shape or circular flat shape.

8. according to the device described in claim 6 or 7, it is characterized in that: fine coal material feeding tube (3) is comprised of with vertical pipeline section horizontal pipeline section, the outlet of fine coal material feeding tube (3) is positioned at the bottom of vertical pipeline section.

9. according to the device described in claim 6 or 7, it is characterized in that: semicoke transfer lime (9) is comprised of vertical pipeline section and inclination pipeline section, vertical pipeline section is stretched in stripping stage (17) by the bottom of stripping stage (17), the top entrance of vertical pipeline section is the entrance of semicoke transfer lime (9), be positioned at the bottom of stripping stage (17), the outlet of inclination pipeline section is the outlet of semicoke transfer lime (9), is connected with the make charcoal bottom of device (7) of tubular type.

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