CN108286705A - A kind of device and method improving gas utilization efficiency - Google Patents

Abstract

A kind of device and method improving gas utilization efficiency, the equipment include：Coal bed gas delivery pipeline, methane normal pressure absorbing unit, catalyst warm-up unit and catalyst oxidation reactor；The catalyst oxidation reactor includes catalytic combustion unit, coal bed gas preheating unit and waste heat recovery unit；The catalyst warm-up unit is used to preheat the catalyst bed in the catalytic combustion unit；The entrance of the coal bed gas preheating unit is connected with the outlet of the coal bed gas delivery pipeline, and the outlet of the coal bed gas preheating unit is connected with the entrance of the catalytic combustion unit.The present invention may be implemented ultralow concentration gas efficiently, economically utilize, to increase substantially coal bed gas efficiency.

Description

A device and method for improving utilization efficiency of coalbed methane

technical field

The invention belongs to the technical field of clean energy, and in particular relates to a device and a method for improving utilization efficiency of coal bed gas.

Background technique

Coalbed methane, also known as gas, is a clean energy source. At present, less coalbed methane is utilized. It is estimated that by the end of 2020, only 30% of the total resources of coalbed methane will be utilized. As shown in Figure 1, gas with a concentration of less than 10% (called ultra-low concentration gas), including wind exhaust gas (with a concentration of about 0.2%), is not utilized and is directly discharged into the atmosphere.

At present, 30 billion cubic meters of methane is emitted from domestic coal mines into the atmosphere every year in ultra-low concentration gas. If they are used as fuel, they can replace nearly 100 million tons of coal, reduce sulfur dioxide emissions by 930,000 tons, NOx by 520,000 tons, and reduce particulate matter emissions by 1.26 million tons. Methane is an important greenhouse gas, and the emission of 30 billion cubic meters of methane is equivalent to the emission of 550 million tons of carbon dioxide. Therefore, it is of great significance to reduce the emission of these gases, and using these ultra-low concentration gases as fuel can supplement the shortage of domestic natural gas supply.

The concentration of ultra-low concentration gas is low, and the air volume is large, which increases the cost of gas utilization and affects the efficiency of gas utilization. The pressure swing adsorption (PSA) method can increase the concentration of ultra-low concentration gas, but it consumes a huge amount of electricity to pressurize the ultra-low concentration gas, so it is not economically feasible. CN104014223A discloses a depleted air methane adsorber, which adopts the temperature swing adsorption method to adsorb methane in the wind exhaust gas, wherein many small filter elements are used, and the thickness of the adsorption material is relatively thin. The technical scheme is based on the small-scale device experiment in the laboratory It is proposed that there are still many technical problems to be broken through in large-scale industrial production. In addition, the adsorber can only increase the methane concentration to 1%, indicating that the structural design is not perfect.

CN103306717A discloses a scheme of adsorption and concentration first, followed by regenerative oxidation. The concentration of the wind exhaust gas is concentrated to 1%, and then enters the regenerative oxidation device for oxidation, and the heat released by the oxidation of the gas is used for power generation, heat supply and other waste heat utilization.

The problems with this method are:

1) Gas waste is large. The gas oxidation unit needs to consume 20% of the total gas to maintain its operating temperature of 1100-1200°C.

2) The heat utilization rate is low. The temperature of the flue gas discharged into the atmosphere by the device is above 130°C, which takes away a lot of heat.

3) The power generation efficiency is low. The higher concentration gas mixed into the wind exhaust gas can directly generate electricity in the gas generator, which can generate at least 3.5kWh per cubic meter, while it can only generate 2.5kWh per cubic meter of gas when mixed into the wind exhaust gas. The more blending, the greater the loss of power generation.

4) The equipment has low efficiency and occupies a large area. The oxidation device uses a large number of honeycomb ceramic regenerators to accumulate the heat released by gas oxidation, and the equipment occupies a large area. Most coal mines in China are built in mountainous areas with little flat land, and the cost of land occupation for implementing this technology is very high.

5) The utilization scale of ultra-low concentration gas is limited. The flow rate of gas with high concentration in coal mine is small and unstable, while the flow rate of gas exhausted by wind is large and the concentration is low. There is not enough mixed high-concentration gas, which affects the utilization of wind exhaust gas (the total amount of methane in wind exhaust gas accounts for more than 50% of all coalbed methane).

6) Generate a large amount of solid waste and pollute the environment. Each regenerative oxidation device uses tens of cubic meters of honeycomb ceramic regenerator. The total amount of regenerator used in the oxidation device of a project is about 1000 cubic meters. These heat accumulators need to be replaced every 1-2 years, resulting in a large amount of solid waste and new environmental pollution.

7) The investment of equipment is large and the economic benefit is poor. The investment of thermal storage oxidation technology power generation is 11,000 yuan/kW, which is not only much higher than 4,500 yuan/kW of thermal power, but also higher than 6,500 yuan/kW of low-concentration gas power generation. The investment return period is usually more than 6 years. This also hinders the large-scale application of this technology in domestic coal mines.

In addition, the gas concentration in this method is low (less than 1.0%). If the gas concentration increases, it will be difficult to control the internal temperature of the regenerative device, and the device will be burned. Therefore, this method still needs to be perfected technically.

Contents of the invention

In order to solve the problems of high utilization cost and low utilization efficiency of coalbed methane in the prior art, the present invention proposes an economical and efficient equipment and method for improving utilization efficiency of coalbed methane.

In order to achieve the above object, on the one hand, the equipment for improving the efficiency of coalbed methane utilization proposed by the present invention includes:

Coalbed methane delivery pipeline, catalyst preheating unit and catalytic oxidation reactor; the catalytic oxidation reactor includes catalytic combustion unit, coalbed methane preheating unit and waste heat recovery unit;

The catalyst preheating unit is used to preheat the catalyst bed in the catalytic combustion unit;

The inlet of the coalbed methane preheating unit is connected to the outlet of the coalbed methane delivery pipeline, and the outlet of the coalbed methane preheating unit is connected to the inlet of the catalytic combustion unit;

In terms of the flow direction of the coal bed gas, the catalytic combustion unit includes a head, a gas distributor and a catalyst bed arranged in sequence;

The high-temperature flue gas generated by the catalytic combustion unit enters the waste heat recovery unit, and the waste heat recovery unit includes a steam generation section and a boiler feed water preheating section arranged in sequence based on the cooling direction of the high temperature gas. The boiler feed water preheating section The section is connected to the boiler feed water pipe, and the boiler feed water enters the steam generating section after being preheated in the boiler feed water preheating section, and the generated steam enters the steam pipe network. Preferably, the waste heat recovery unit also includes a steam superheating section , the steam generated by the steam generation section enters the steam superheating section, and the superheated steam generated enters the steam pipe network.

Preferably, the equipment includes a methane atmospheric pressure adsorption unit, and the methane atmospheric pressure adsorption unit includes a plurality of adsorption towers, and the inlets of the adsorption towers are respectively connected to the air exhaust gas pipeline and the high-temperature flue gas from the catalytic oxidation reactor. The outlet of the adsorption tower is connected with the coalbed methane delivery pipeline and the discharge pipeline respectively, and the gas exhaust pipeline, the high temperature flue gas pipeline, the outlet of the adsorption tower are connected with the coalbed methane delivery pipeline. Valves are arranged between the pipelines and on the discharge pipeline.

Preferably, the catalyst preheating unit includes a first induced draft fan and an electric heater, the inlet of the electric heater is connected to the outlet of the first induced draft fan, and the outlet of the electric heater is connected to the catalytic combustion unit connected to the entrance. Preferably, when the catalytic oxidation reactor is a small catalytic oxidation reactor, the catalyst preheating unit is an electric heating wire or an electric heating rod built in the catalytic oxidation reactor.

Preferably, the equipment further includes a second induced draft fan and an air conveying pipeline, the outlet of the air conveying pipeline is connected to the inlet of the second induced draft fan, and the outlet of the second induced draft fan is connected to the outlet of the coalbed methane conveying pipeline. The entrance is connected. Preferably, an air filter is provided between the outlet of the second induced draft fan and the coalbed methane delivery pipeline.

Preferably, the waste heat recovery unit further includes a steam drum for separating steam and liquid, and the boiler feed water enters the steam generating section through the steam drum after being preheated in the boiler feed water preheating section, and the generated steam and water The mixture is returned to the steam drum for separation, and the separated steam enters the steam pipe network.

Preferably, the catalyst preheating unit includes a first filter, and the coalbed methane delivery pipeline includes a second filter and a flame arrester. Preferably, the equipment further includes a low-concentration gas delivery pipeline, and the low-concentration gas delivery pipeline includes a second filter and a flame arrester. The pipeline is connected with the coalbed methane transmission pipeline.

On the other hand, the present invention also proposes a method for improving utilization efficiency of coalbed methane by using the equipment, including:

In the preheating stage, use the catalyst preheating unit to preheat the catalyst bed to the specified temperature, turn off the catalyst preheating unit, and enter the normal operation stage;

In the normal operation stage, the coalbed methane is preheated by the coalbed methane preheating unit, and the preheated coalbed methane is distributed to the catalyst bed through the head and the gas distributor in turn, so that the preheated coalbed methane is under the action of the catalyst reaction to obtain high-temperature flue gas;

The high-temperature flue gas passes through the steam generation section and the boiler feed water preheating section in turn for waste heat recovery, and then passes through the coalbed methane preheating unit to recover heat, and then discharges up-to-standard flue gas.

Preferably, the method further includes the step of concentrating the exhaust gas to a predetermined concentration range, the step comprising: inputting the exhaust gas into an adsorption tower, the adsorbent in the adsorption tower absorbs the methane in the exhaust gas, and vent methane-free air into the atmosphere;

The high-temperature flue gas from the catalytic combustion reactor is input into the adsorption tower, the methane is desorbed, and sent to the coalbed methane preheating unit, and at the same time, another adsorption tower is used to adsorb the methane in the coalbed methane.

Preferably, in the method, two or more adsorption towers alternately perform methane adsorption and desorption, and the desorbed methane is continuously transported to the catalytic oxidation reactor.

Preferably, the method further comprises superheating the steam to obtain superheated steam.

Compared with prior art, the present invention has following characteristics:

1) Improved gas utilization. Under the action of the catalyst, the operating temperature of the reactor is lowered to 400°C, and all the oxidized gas is released without consumption.

2) The utilization rate of heat is improved. The exhaust gas temperature is 60°C, and the heat dissipation of the device is reduced, which improves the heat utilization rate by 10% compared with the regenerative oxidation technology.

3) High power generation efficiency. Due to the highly integrated functions of the device, the heat used for power generation is 10% more than that of regenerative oxidation technology, and the power generation efficiency is improved.

4) No solid waste discharge. The regenerative body is used for a long time, the catalyst can be regenerated, no solid waste is formed, and the environment is friendly.

5) Economic benefits are improved. The equipment cost of the new process is reduced, the land occupation is reduced to 1/4 of the existing thermal storage oxidation technology, and the project investment is reduced to 1/2 of the existing thermal storage oxidation technology, so the economic benefits are good.

Description of drawings

Figure 1 shows the utilization of coalbed methane resources;

Fig. 2 is a flow chart of the gas utilization method in the present invention;

Fig. 3 is a schematic diagram of equipment in an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The present invention adopts two core technologies and uses a new process route to realize the efficient and economical utilization of ultra-low concentration gas, so as to greatly improve the efficiency of coalbed methane, as shown in Figure 2:

1. Adsorb ultra-low concentration gas at normal temperature and pressure, and desorb it by temperature swing adsorption method. Increase the concentration of ultra-low concentration gas by 10 times, and increase its concentration to more than 2%.

2. Utilize a catalytic oxidation (Catalytic Oxider, CO) device (also called a catalytic combustion device) to directly burn gas with a concentration of more than 2%, and release 100% of the heat of gas oxidation.

According to the flow of the new process, the ultra-low concentration gas is concentrated first, and the concentrated gas releases heat in the catalytic combustion device, which is used for steam power generation and waste heat utilization (including high-temperature desorption). The area occupied by the new process is 1/4 of the existing thermal storage oxidation technology, and the project investment is reduced to 1/2 of the existing thermal storage oxidation technology, so as to realize the efficient utilization of ultra-low concentration gas and greatly reduce the utilization of ultra-low concentration gas the cost of.

The equipment for improving the utilization efficiency of coalbed methane proposed by the present invention includes: coalbed methane delivery pipeline, catalyst preheating unit and catalytic oxidation reactor; the catalyst preheating unit includes a first induced draft fan and an electric heater, and the catalytic oxidation reactor Including catalytic combustion unit, coalbed methane preheating unit and waste heat recovery unit;

The inlet of the electric heater is connected with the outlet of the first induced draft fan;

The inlet of the catalytic combustion unit is connected with the outlet of the electric heater;

The inlet of the coalbed methane preheating unit is connected with the outlet of the coalbed methane delivery pipeline;

The inlet of the catalytic combustion unit is connected with the outlet of the coalbed methane preheating unit;

In terms of the flow direction of preheated gas or coalbed methane raw material gas, the catalytic combustion unit includes a head, a gas distributor and a catalyst bed arranged in sequence;

The high-temperature flue gas generated by the catalytic combustion unit enters the waste heat recovery unit, and the waste heat recovery unit includes a steam generation section and a boiler feed water preheating section arranged in sequence in terms of the cooling direction of the high-temperature gas. The boiler feed water preheating section is connected to the boiler feed water pipeline, and the boiler feed water enters the steam generation section after being preheated in the boiler feed water preheating section, and the generated steam enters the steam pipe network.

When superheated steam is needed, the waste heat recovery unit also includes a steam superheating section. In terms of the cooling direction of high-temperature gas, the waste heat recovery unit includes a steam superheating section, a steam generation section and a boiler feed water preheating section arranged in sequence. The steam generated by the steam generating section enters the steam superheating section, and the generated superheated steam enters the steam pipe network.

The pressure of each pipeline can be adjusted according to actual needs. For example, the steam superheating section can be a high-pressure steam superheating section, and the boiler feed water can be high-pressure boiler feed water.

The equipment also includes a methane atmospheric pressure adsorption unit, the methane atmospheric pressure adsorption unit includes a plurality of adsorption towers, the inlets of the adsorption towers are respectively connected with the air exhaust gas pipeline and the high temperature flue gas pipeline from the catalytic oxidation reactor , the outlet of the adsorption tower is connected to the coalbed methane delivery pipeline and the discharge pipeline respectively, on the air exhaust gas pipeline, on the high-temperature flue gas pipeline, between the outlet of the adsorption tower and the coalbed methane delivery pipeline There are valves in the room and on the discharge pipeline.

The equipment also includes a second induced draft fan and an air conveying pipeline, the outlet of the air conveying pipeline is connected to the inlet of the second induced draft fan, and the outlet of the second induced draft fan is connected to the inlet of the coalbed methane conveying pipeline.

The catalytic oxidation reactor may be several catalytic oxidation reactors arranged in parallel.

The coalbed methane preheating unit is a heat exchange tube bundle or a plate heat exchanger.

According to the requirement of generating steam, the steam generating section may be provided with multiple sets of heat exchange coils.

The waste heat recovery unit also includes a steam drum for separating steam and liquid. After the boiler feed water is preheated in the boiler feed water preheating section, it enters the steam generating section through the steam drum, and the mixture of steam and water is returned to the steam generating section. The steam drum is separated, and the separated steam enters the steam pipe network.

The present invention also provides a method for using the equipment to process coalbed methane, comprising the following steps:

In the preheating stage, use the catalyst preheating unit to preheat the catalyst bed, close the catalyst preheating unit, and enter the normal operation stage;

In the normal operation stage, the coalbed methane is preheated by the coalbed methane preheating unit, and the preheated coalbed methane is distributed to the catalyst bed through the head and the gas distributor in turn, so that the preheated coalbed methane is under the action of the catalyst reaction to obtain high-temperature flue gas;

The high-temperature flue gas passes through the steam superheating section, the steam generating section and the boiler feed water preheating section successively for waste heat recovery, and then the coalbed methane preheating unit recovers heat, and then discharges the low-temperature flue gas.

In one embodiment, the device of the present invention is shown in FIG. 3 . It is composed of methane atmospheric pressure adsorption unit, induced draft fan, catalytic oxidation reactor, catalyst preheating unit and supporting pipelines and valves.

The methane atmospheric pressure adsorption unit is composed of a first adsorption tower 1 and a second adsorption tower 2, one of which is used to absorb methane in the wind exhaust gas and discharge methane-free air into the atmosphere, and the other tower uses high-temperature flue gas The gas desorbs methane from the adsorption bed, and the desorbed gas is mixed with the low-concentration gas to be utilized, and then sent to the catalytic oxidation reactor 3.

After the adsorption tower is full of methane, it is switched to a desorption tower, and the methane is desorbed with high-temperature flue gas. After the methane in the desorption tower is completely desorbed, it is switched to an adsorption tower through a valve to absorb methane.

Used two absorption towers in the present embodiment, but also can adopt three towers, or multi-tower form.

The atmospheric pressure methane adsorbent in the absorption tower can be molecular sieve, MOF (metal-organicframework) material, or other porous materials. High-performance adsorption materials can reduce the amount of absorbent and reduce the cost of the absorption tower. The shape of the adsorbent can be granular or monolithic (honeycomb form), and various other forms.

Through atmospheric pressure adsorption, the concentration of wind exhaust gas is increased, the processing capacity of the oxidation device is reduced, the number of oxidation devices is greatly reduced, and the land occupation required by the project is reduced. Atmospheric pressure adsorption consumes the least amount of electric energy, and the heat for desorbing methane comes from the oxidation device without external heat.

The second induced draft fan 4 will mix air into the coal-bed methane as required to control the concentration of the coal-bed methane entering the catalytic oxidation reactor 3 and avoid catalyst bed overheating in the reactor.

The catalytic oxidation reactor 3 realizes the catalytic combustion of coal bed gas, and transfers the heat of combustion to the medium to be heated in the form of infrared radiation and high-temperature flue gas convection. The heat carried by the flue gas is used to preheat the coal bed gas to realize the recovery of waste heat, so as to improve the thermal efficiency of the catalytic combustion equipment.

The structure of the catalytic oxidation reactor 3 is, from the bottom up, a head, a gas distributor, a catalyst bed, a waste heat recovery unit for waste heat recovery (such as a tube heat exchanger or a plate heat exchanger), and a coal seam preheater. CBM preheating unit (such as plate heat exchanger) and chimney for flue gas discharge. After passing through the head of the reactor and the gas distributor, the flow velocity of the coalbed methane along the section of the reactor is uniform, so that the coalbed methane can be burned evenly on the catalyst bed, and local overheating of the catalyst bed can be avoided.

After the boiler feed water is preheated in the boiler feed water preheating section, it enters the steam generation section through the steam drum 5, and the mixture of steam and water produced returns to the steam drum 5 for separation, and the separated steam enters the steam superheating section to form superheated steam, and the superheated steam enters steam network.

The catalyst in the catalytic oxidation reactor 3 can be a noble metal catalyst, and the temperature of the flue gas formed after catalytic combustion is 500-600°C. In practical applications, metal oxide catalysts can also be used, and the temperature of the flue gas can reach 1000 ° C, or other types of catalysts can be replaced.

Usually, the air volume of a return air shaft is equivalent to that of this embodiment, and the flow rate of low-concentration gas is also equivalent to that of this embodiment. Therefore, a catalytic oxidation device is installed, which occupies a small area, has simple pipeline layout, and saves investment and maintenance costs. Of course, multiple small catalytic oxidation devices can also be used in parallel.

In one embodiment, the catalyst preheating device is composed of a first induced draft fan 6 and an electric heater 7, and is used to preheat the catalyst bed before the catalytic oxidation reactor 3 enters normal operation, so that the coal bed gas can be completely heated in the catalyst bed. combustion. In addition, for small catalytic combustion equipment, built-in electric heating wires, electric heating rods, etc. can be used to preheat the catalyst bed.

In order to prevent the particles in the air and coalbed methane from clogging the catalyst, it is necessary to install suitable filters on the pipeline, such as air filter 8, fuel filter 9 and start-up filter 10. The flame arrester 11 on the coalbed methane delivery pipeline can prevent the coalbed methane system from exploding after a fire or explosion accident occurs in the catalytic combustion device.

When using the equipment to catalyze the combustion of coalbed methane, firstly, the catalyst bed of the catalytic oxidation reactor 3 is preheated to a specified temperature. Start the first induced draft fan 6 and the electric heater 7, send the hot air into the reactor 3, after passing through the head of the reactor and the gas distributor, the hot air evenly preheats the catalyst bed, and the catalyst bed is preheated to the set temperature Finally, close the first induced draft fan 6 and the electric heater 7, and close the valve V9 on the connecting pipeline between the outlet of the electric heater and the reactor.

Open V1, V6, close V2, V5. The wind exhaust gas enters the first adsorption tower 1 through V1, absorbs the methane from the wind exhaust gas, and discharges the air through V6. Close V3, V4, V7, V8.

Start the second induced draft fan 4 as needed to mix air into the low-concentration gas so that its concentration is lower than the explosion limit of methane. Low-concentration gas enters the head and gas distributor of reactor 3 from the pipeline, and catalytic combustion occurs on the catalyst bed, and the heat of gas oxidation is transferred to the boiler feed water in the form of infrared radiation and high-temperature flue gas convective heat transfer. steam, and superheat the steam. The remaining heat is transferred to the coal bed gas that needs to be preheated to realize waste heat recovery. The exhaust gas temperature is lower than 100°C to recover the latent heat in the flue gas and further improve the thermal efficiency of the equipment.

The superheated steam enters the steam drum 5 for circulation, and the dry steam enters the steam pipe network for the steam turbine to generate electricity.

Coal bed gas needs to be preheated to a set temperature before entering the reactor to maintain the temperature of the catalyst bed so that methane can undergo continuous catalytic combustion on the catalyst bed.

After the first adsorption tower 1 is full of methane, open V2 and V5, close V1 and V6, high-temperature flue gas enters the first adsorption tower 1 through V2, desorbs methane, and enters the low-concentration gas pipeline from V5. Turn on V3 and V8, and the second adsorption tower 2 starts to adsorb methane.

After one adsorption cycle, the second adsorption tower 2 is full of methane, and then the valve is switched to desorb the methane in the second adsorption tower 2 with high-temperature flue gas, and use the first adsorption tower 1 to adsorb methane. In this way, the desorbed methane can be continuously sent to the catalytic oxidation reactor, thereby realizing a smooth and continuous catalytic combustion reaction in the catalytic oxidation reactor.

The technological process of the invention can simultaneously utilize the air exhaust gas and low concentration gas, and the concentrated air exhaust gas and low concentration gas can be oxidized and utilized in the same catalytic oxidation device. It simplifies the technological process, reduces the project area and reduces the project investment. At the same time, the wind exhaust gas and low-concentration gas can be used to utilize all the gas in the coal mine, that is, to achieve the goal of zero gas emission.

Example 1

A catalytic oxidation device utilizes low-concentration gas with a methane concentration of 5% from coal mines and wind exhaust gas with a methane concentration of 0.2% to generate electricity. The flow rate of low-concentration gas is 300Nm ³ /min, the flow rate of wind exhaust gas is 14000Nm ³ /min, and 35 tons of 4.3MPa, 384℃ steam is produced per hour to drive the steam turbine with a power generation capacity of 6MW. By adopting the process of the invention, all the gas discharged into the atmosphere from coal mines can be utilized to realize zero gas discharge from coal mines.

The adsorbent is molecular sieve 5A. Under normal pressure, each kg of molecular sieve absorbs 1g of methane, the adsorption/desorption cycle is 10min, and the amount of molecular sieve used in each adsorption tower is 300 tons. After the air exhaust gas passes through the adsorption tower, the flow rate is 1400Nm ³ /min, and the concentration is 2% low-concentration gas. After mixing the two concentrations of gas, the flow rate is 1700Nm ³ /min, and the concentration is 2.5%.

The cross-sectional size of the catalytic combustion reactor is 6.0m×6.0m, the shape of the head is conical, the gas distributor adopts a two-stage combined sieve plate structure, and the number, spacing and size of the openings are designed according to the principle of equal resistance. The catalyst is a monolithic catalyst loaded with 0.6w% noble metal, the noble metal is palladium, the carrier is cordierite honeycomb ceramics of 200 mesh, and the catalyst consumption is 10m ³ . heater. The coalbed methane (low-concentration gas) preheating unit is a plate-type air preheater.

First, open the valve V9, start the first induced draft fan 6 and the electric heater 7, and send the hot air into the reactor 3. After passing through the head of the reactor and the gas distributor, the hot air evenly preheats the catalyst bed. After preheating to 400°C, close the first induced draft fan 6 and the electric heater 7, and close the valve V9 on the connecting pipeline between the outlet of the electric heater and the reactor.

Low-concentration gas enters the head and gas distributor of reactor 3 from the pipeline, and catalytic combustion occurs on the catalyst bed, and the 5.6MPa boiler feed water is heated by infrared radiation and 550°C flue gas convective heat transfer to produce 4.3MPa of water vapor. . The cooled flue gas transfers heat to the coalbed methane in the coalbed methane preheating unit. The exhaust gas temperature of this equipment is controlled below 100°C to recover the latent heat in the flue gas.

The data acquisition and control of catalytic oxidation reactor 3 are completed by Siemens S7-300 PLC.

Compared with the previous regenerative oxidation method, the concentration of methane in the present invention can reach 2%, the heating efficiency is improved, and there is no need to switch the flow direction and no heat storage structure, and the system is simple and stable. Low failure rate; built-in waste heat boiler, no need to extract flue gas, waste heat boiler does not exhaust 300-450 ℃ flue gas, high heat utilization efficiency, and does not need a blender to mix flue gas at different temperatures; when using precious metal catalysts, The temperature of the flue gas is 400-600°C. When metal oxide catalysts are used, the temperature of the flue gas can reach 1000°C; according to the different desorption properties of the adsorbent, the temperature of the degassed gas can be adjusted appropriately; the temperature of the low-temperature flue gas can be as low as 60°C. The combination of the above technical advantages makes the technical solution of the present invention occupy only 1/4 of the regenerative oxidation technology, and the project investment is reduced to 1/2 of the regenerative oxidation technology, and the heat utilization efficiency is 20% higher than that of the regenerative oxidation solution above.

The types of gas that can be utilized by the present invention cover coalbed methane resources that have not been utilized so far, thereby realizing zero discharge of coal mine gas, and becoming a breakthrough in large-scale, efficient and economical utilization of coalbed methane in China.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. a kind of equipment improving gas utilization efficiency, which is characterized in that including：

Coal bed gas delivery pipeline, catalyst warm-up unit and catalyst oxidation reactor；The catalyst oxidation reactor includes catalysis Fuel element, coal bed gas preheating unit and waste heat recovery unit；

The catalyst warm-up unit is used to preheat the catalyst bed in the catalytic combustion unit；

The entrance of the coal bed gas preheating unit is connected with the outlet of the coal bed gas delivery pipeline, the coal bed gas preheating unit Outlet be connected with the entrance of the catalytic combustion unit；

In terms of the flow direction of coal bed gas, the catalytic combustion unit includes the end socket, gas distributor and catalyst bed set gradually Layer；

The high-temperature flue gas that the catalytic combustion unit generates enters the waste heat recovery unit, with the cooling direction of high-temperature gas Meter, the waste heat recovery unit include the steam generation section set gradually and boiler feedwater preheating section, the boiler feedwater preheating Section is connected with boiler feedwater pipeline, and boiler feedwater enters the steam generation after the boiler feedwater preheating section is preheated Section, the steam of generation enter steam pipe network, it is preferable that the waste heat recovery unit further includes steam superheating section, the steam hair The steam that raw section generates enters the steam superheating section, and the superheated steam of generation enters steam pipe network.

2. equipment as described in claim 1, which is characterized in that the equipment includes methane normal pressure absorbing unit, the methane Normal pressure absorbing unit includes multiple adsorption towers, and the entrance of the adsorption tower is respectively with wind resource assessment pipeline and from the catalysis oxygen The high-temperature flue gas pipeline for changing reactor is connected, the outlet of the adsorption tower respectively with the coal bed gas delivery pipeline and discharge tube Be connected, on the wind resource assessment pipeline, on the high-temperature flue gas pipeline, the outlet of the adsorption tower and the coal seam letter shoot It is both provided with valve between road and on the discharge tube.

3. equipment as described in claim 1, which is characterized in that the catalyst warm-up unit includes that the first air-introduced machine adds with electricity Hot device, the entrance of the electric heater are connected with the outlet of first air-introduced machine, and the outlet of the electric heater is urged with described The entrance for changing fuel element is connected, it is preferable that described to urge when the catalyst oxidation reactor is compact catalytic oxidation reactor Agent preheating unit is the heating wire or electrically heated rod being built in the catalyst oxidation reactor.

4. equipment as described in claim 1, which is characterized in that the equipment further includes the second air-introduced machine and air delivery pipe Road, the outlet of the airflow pipe are connected with the second air-introduced machine entrance, the outlet of second air-introduced machine with it is described The entrance of coal bed gas delivery pipeline is connected, it is preferable that between the outlet and the coal bed gas delivery pipeline of second air-introduced machine It is provided with air filter.

5. equipment as described in claim 1, which is characterized in that the waste heat recovery unit further includes separate vapour and liquid Drum, boiler feedwater enter the steam generation section after the boiler feedwater preheating section is preheated through the drum, generate Steam and the mixture of water return to the drum and detached, the steam isolated enters steam pipe network.

6. equipment as described in claim 1, which is characterized in that the catalyst warm-up unit includes first filter, described Coal bed gas delivery pipeline includes the second filter and spark arrester, it is preferable that and the equipment further includes low concentration gas conveyance conduit, The low concentration gas conveyance conduit is connected with the coal bed gas delivery pipeline.

7. a kind of method improving gas utilization efficiency using any one of the claim 1-6 equipment, which is characterized in that packet It includes：

In warm-up phase, catalyst bed is preheating to assigned temperature using catalyst warm-up unit, closes catalyst warm-up list Member, into normal operation phase；

In normal operation phase, coal bed gas is preheated using coal bed gas preheating unit, by the coal bed gas after preheating successively by sealing Head, gas distributor are distributed to catalyst bed, so that the coal bed gas after preheating is reacted under the effect of the catalyst, are obtained high temperature cigarette Gas；

The high-temperature flue gas passes through steam generation section and carries out waste heat recovery with boiler feedwater preheating section successively, pre- using coal bed gas After hot cell recycles heat, low-temperature flue gas is discharged.

8. the method for claim 7, which is characterized in that the method further includes that wind resource assessment is concentrated into predetermined concentration The step of range, the step include：Wind resource assessment is inputted into an adsorption tower, the adsorbent absorption wind row watt in the adsorption tower Methane in this, and the air without methane is discharged into air；

The high-temperature flue gas from the catalytic combustion reactor is inputted in the adsorption tower, desorbs methane, and be transported to coal Layer gas preheating unit, while utilizing the methane in another adsorption tower absorption coal bed gas.

9. method as claimed in claim 8, which is characterized in that in the method, two or more adsorption towers are handed over For the absorption and desorption of methane is carried out, the methane desorbed is conveyed continuously in the catalyst oxidation reactor.

10. the method for claim 7, which is characterized in that the method further includes making steam superheating, and obtain overheat and steam Vapour.