Energy-saving device and method for graded pressure charging and releasing of coal feeding device of coal gasifier

Abstract

According to the energy-saving device and method for graded pressure charging and releasing of the coal feeding device of the coal gasifier, the control system is used for coordinating the two coal feeding systems to alternately execute coal feeding, pressure charging, discharging and pressure releasing operations. And during coaling, opening the coal lock upper valve of the coal lock of the corresponding coaling system, and enabling the coal in the coal bunker to fall into the coal lock through the coaling chute until the set coaling quantity is reached. During pressurizing, the control system sequentially opens the pressurizing valves in the pressurizing branches according to the pressure grade from low to high, and the coal lock gas in the coal lock gas buffer pipe is used for pressurizing the coal lock. And during discharging, a coal lock lower valve of the coal lock is opened, and coal enters the gasification furnace from the transition bin. During pressure relief, according to the same principle, the control system sequentially opens the pressure relief valves in the pressure relief branches from the high pressure level to the low pressure level until pressure relief is completed. Through the graded pressure charging and discharging design, graded collection is performed according to pressure grades during pressure discharging, and meanwhile, the system is recycled as a pressure charging gas source, so that the system is more efficient, energy-saving and environment-friendly, the configuration scale of the coal lock gas compressor can be effectively reduced, and the energy consumption loss is reduced.

Description

Technical Field

[0001] This invention belongs to the field of coal gasification technology, and specifically relates to an energy-saving device and method for staged pressure charging and depressurization of a coal gasification furnace coal feeding device. Background Technology

[0002] In the field of pressurized coal gasification technology, apart from coal-water slurry gasifiers, other types of pressurized gasifiers (such as pulverized coal fixed-bed pressurized gasifiers, fluidized-bed gasifiers, moving-bed / fixed-bed gasifiers, etc.) typically employ a dual-coal-lock intermittent coal feeding method to continuously supply coal for gasification. In actual operation, the coal locks need to undergo a cyclical depressurization and repressurization process: before coal feeding, the coal locks need to be depressurized from the gasifier pressure to atmospheric pressure, and then the raw coal enters the coal locks from the coal bunker via a coal feeding chute; after the coal locks are full, they are repressurized to balance the gasifier pressure, thus allowing the coal to smoothly enter the gasifier. This cyclical process is a crucial link in ensuring the continuous operation of the gasifier.

[0003] However, the existing coal lock gas treatment methods still have several common problems, mainly reflected in:

[0004] 1. Environmental pollution and resource waste: The low-pressure coallock gas generated during the coallock depressurization process usually contains a certain amount of combustible and harmful components (such as CO, H2, etc.). Currently, most processes directly vent or ignite it for emission, which not only wastes energy but also causes pollutants to directly enter the atmosphere, causing negative impacts on the environment and failing to meet the environmental protection requirements of green production.

[0005] 2. High Equipment Investment and Limitations to Scale: If carbon dioxide recovered in the later stages is used to pressurize the coal lock, high-power compressors, large buffer tanks, and other supporting equipment are required. This results in a complex system, a large footprint, and high initial investment and operating costs. Especially in large-scale plants with multiple gasifiers operating in parallel, the demand for carbon dioxide increases significantly, further exacerbating equipment and energy consumption pressures. Furthermore, using carbon dioxide for pressurization leads to an increase in the carbon dioxide concentration in the coal lock gas, resulting in secondary carbon dioxide emissions during subsequent recovery processes, which contradicts the current emission reduction requirements of the "dual carbon" target.

[0006] Therefore, it is necessary to develop a more efficient, energy-saving and environmentally friendly method for coal lock gas treatment and pressurization / depressurization to improve the overall performance and sustainable development capability of pressurized gasification technology. Summary of the Invention

[0007] The purpose of this invention is to provide an energy-saving device and method for staged charging and depressurization of coal gasification furnace coal feeding device, which is more efficient, energy-saving and environmentally friendly, and can effectively reduce the configuration scale of coal lock compressor and reduce energy consumption loss.

[0008] To solve the above-mentioned technical problems, the present invention provides an energy-saving device for staged charging and depressurization of coal gasification furnace coal feeding device, including two coal feeding systems, a gasification furnace, a coal lock charging and depressurization pipeline system, a programmable valve group and a control system;

[0009] Each of the coal feeding systems includes a coal bunker, a coal feeding chute, a coal lock, and a transition chamber connected in sequence, and the transition chamber of each of the coal feeding systems is connected to the inlet of the gasifier;

[0010] The coal lock pressurization and depressurization pipeline system includes multiple coal lock gas buffer pipes of different pressure levels, multiple pressurization branches connected to the coal lock and the multiple coal lock gas buffer pipes of different pressure levels, and multiple depressurization branches.

[0011] The programmable valve group is installed on each of the coal locks and the coal lock pressure charging and depressurization pipeline system;

[0012] The control system is connected to the programmable valve group and is configured to control each of the coal locks to alternately perform coal feeding, pressurizing, material discharge to the transition bin, and depressurization operations.

[0013] Optionally, the above-mentioned energy-saving device also includes an ejector, a low-pressure coal lock gas scrubber, a scrubbing separator, a gas holder, and a compressor;

[0014] The ejector's suction port is connected to the top of the coal lock via an ejector valve;

[0015] The ejector outlet is sequentially connected to the low-pressure coal gas lock scrubber, the scrubbing separator, the gas holder, and the compressor.

[0016] Optionally, in the above-mentioned energy-saving device, the multiple coal lock gas buffer pipes of different pressure levels include an intermediate coal lock gas buffer pipe, a primary coal lock gas buffer pipe, a secondary coal lock gas buffer pipe and a tertiary coal lock gas buffer pipe arranged in parallel, and the intermediate coal lock gas buffer pipe is connected to the inlet of the compressor.

[0017] The programmable valve group includes: upper coal lock valve and lower coal lock valve installed on each coal lock, pressure valves connected in series on each pressure charging branch, and valves connected in series on each pressure relief branch.

[0018] This invention also provides an energy-saving method for staged pressure charging and depressurization of a coal gasification furnace coal feeding device, using the energy-saving device for staged pressure charging and depressurization of a coal gasification furnace coal feeding device described above. The energy-saving method includes:

[0019] Step S100: After one of the two coal locks is empty and depressurized, the control system closes all valves on the coal lock charging and depressurization pipeline system. The ejector valve of the ejector is normally open. The coal lock valve and the coal feeding chute valve of the coal lock are opened to add coal to the coal lock. After the coal is added, the coal feeding chute valve and the coal lock valve are closed in sequence.

[0020] Step S200: Perform multi-stage pressurization on the coal lock;

[0021] Step S300: Open the lower valve of the coal lock and put the coal into the transition chamber and then into the gasifier; after venting, close the lower valve of the coal lock.

[0022] Step S400: Perform multi-stage depressurization on the coal lock, then return to step S100;

[0023] During the process of one of the two coal locks adding coal to the gasifier in step S300, the control system controls the other of the two coal locks to synchronously execute the pressurization process in step S200; the two coal locks work alternately.

[0024] Optionally, in the above energy-saving method, step S200 includes: sequentially increasing the pressure of the coal lock through the primary pressurization valve of the primary coal lock gas buffer pipe, the secondary pressurization valve of the secondary coal lock gas buffer pipe, and the tertiary pressurization valve of the tertiary coal lock gas buffer pipe to balance the pressure of the corresponding level of coal lock gas buffer pipe; finally, opening the balancing valve with the transition chamber, and closing it after balancing the pressure of the two.

[0025] Optionally, in the above energy-saving method, step S400 includes: releasing the pressure of the coal lock in stages through the primary pressure relief valve of the three-stage coal lock gas buffer pipe, the secondary pressure relief valve of the two-stage coal lock gas buffer pipe, and the tertiary pressure relief valve of the first-stage coal lock gas buffer pipe in sequence until it is balanced with the pressure of the corresponding level of coal lock gas buffer pipe; then releasing the pressure to the intermediate coal lock gas buffer pipe pressure through the tertiary pressure relief valve of the intermediate coal lock gas buffer pipe; and finally releasing the pressure to near atmospheric pressure through the 5th pressure relief valve.

[0026] Optionally, the above energy-saving method also includes step S210 between step S100 and step S200, which involves testing the valve on the closed coal lock for leaks: opening the three-stage pressurization valve of the three-stage coal lock gas buffer pipe, briefly filling the coal lock with pressurized gas and then closing it, monitoring the pressure of the coal lock, and if the pressure drop is lower than the threshold within a set time, the leak test is qualified.

[0027] Optionally, the above energy-saving method also includes step S410 between step S300 and step S400, which involves testing the closed coal lock valve for leaks: opening the pressure relief valve four times to briefly release the pressure inside the coal lock before closing it, monitoring the coal lock pressure, and if the pressure rise is lower than the threshold within a set time, the leak test is considered successful.

[0028] Optionally, in the above energy-saving method, the setting time is 5 seconds and the threshold is 50 kPa.

[0029] Optionally, in the above energy-saving method, in step S200, the specific pressure of the multi-stage pressurization is as follows: first pressurization to 2.5MPa±0.3MPa, second pressurization to 3.3MPa±0.3MPa, third pressurization to 3.9MPa±0.3MPa, and finally balanced with the transition chamber to 4.3MPa±0.3MPa.

[0030] And / or, in step S400, the specific pressures for the multi-stage pressure relief are: first pressure relief to 3.9MPa±0.3MPa, second pressure relief to 3.3MPa±0.3MPa, third pressure relief to 2.5MPa±0.3MPa, fourth pressure relief to 0.9MPa±0.3MPa, and finally pressure relief to below 0.05MPa.

[0031] This invention provides an energy-saving device and method for staged pressure charging and depressurization in a coal gasification furnace coal feeding device, the advantages of which are:

[0032] The control system coordinates two coal feeding systems to alternately perform coal feeding, pressurization, discharge, and depressurization operations. During coal feeding, the upper valve of the coal lock in the corresponding coal feeding system is opened, and coal from the coal bunker falls into the coal lock via the coal feeding chute until the set coal loading amount is reached. The upper valve of the coal lock is then closed, completing the coal feeding process. During pressurization, the control system sequentially opens the coal lock gas buffer pipes and corresponding pressurization valves in the pressurization branches according to pressure levels from low to high, using the coal lock gas stored in the buffer pipes to pressurize the coal locks. When the coal lock pressure reaches equilibrium with the pressure in the corresponding coal lock gas buffer pipe, the pressurization valve for that level is closed, and the coal lock gas buffer pipe and pressurization valve for the next level are opened until pressurization is complete. During discharge, the lower valve of the coal lock is opened, and coal inside the coal lock falls into the transition chamber under gravity, then enters the gasifier through pipelines. During the depressurization process, the pressure inside the coal lock decreases due to the reduction in coal quantity, simultaneously generating dust-laden coal lock gas. This gas is temporarily stored in the coal lock gas buffer pipe through the coal lock and pressure relief valve on the depressurization branch. After discharge, the control system sequentially opens the coal lock gas buffer pipe and corresponding pressure relief valve in the depressurization branch according to the pressure level from high to low. Residual coal lock gas in the coal lock is discharged into the corresponding coal lock gas buffer pipe through the pressure relief valve. When the coal lock pressure reaches equilibrium with the corresponding coal lock gas buffer pipe pressure, the pressure relief valve for that level is closed, and the coal lock gas buffer pipe and pressure relief valve for the next level are opened until depressurization is complete. The coal lock returns to normal pressure, preparing for the next round of coal feeding. After one coal feeding system completes discharge, the control system automatically switches to another coal feeding system and repeats the above steps.

[0033] In the above setup, the staged pressurization and depressurization design allows for the collection of gas according to pressure level during depressurization. Simultaneously, the gas is also recycled as a pressurization source, resulting in energy savings and no environmental impact from external emissions. Compared to traditional single-stage pressurization and depressurization devices, this device reduces the consumption of externally supplied high-pressure gas, making it more efficient, energy-saving, and environmentally friendly. It can effectively reduce the scale of coal-lock gas compressor configurations and minimize energy losses. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0035] Figure 1 This is a process flow diagram of the coal lock pressure charging and depressurization of an energy-saving device for staged pressure charging and depressurization of a coal gasifier feeding device provided in an embodiment of the present invention;

[0036] Figure 2 The diagram below illustrates the coal feeding process of a staged pressurization and depressurization energy-saving device for a coal gasifier, as provided in an embodiment of the present invention.

[0037] In the image above:

[0038] 100-Coal Bunker;

[0039] 200 - Coal feeding chute; 210 - First coal feeding chute; 220 - Second coal feeding chute; 230 - Coal feeding chute valve;

[0040] 300 - Coal lock; 310 - First coal lock; 320 - Second coal lock; 330 - Upper valve of coal lock; 340 - Lower valve of coal lock;

[0041] 400 - Transition chamber; 410 - Balance valve;

[0042] 500 - Ejector; 510 - Ejector valve;

[0043] 600 - Intermediate coal gas lock buffer pipe; 610 - Four-stage pressure relief valve;

[0044] 700 - Primary coal gas lock buffer pipe; 710 - Tertiary pressure relief valve; 720 - Primary pressurization valve;

[0045] 800 - Secondary coal gas lock buffer pipe; 810 - Secondary pressure relief valve; 820 - Secondary pressurization valve;

[0046] 900 - Three-stage coal gas lock buffer pipe; 910 - Primary pressure relief valve; 920 - Tertiary pressure charging valve;

[0047] 1000-Low-pressure coal lock gas scrubber;

[0048] 1100 - Washing Separator;

[0049] 1200 - Gas holder; 1210 - Gas holder inlet valve; 1220 - Gas holder outlet valve;

[0050] 1300 - Compressor; 1310 - Compressor valve;

[0051] 1010 - Five-stage pressure relief valve. Detailed Implementation

[0052] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0053] The core of this invention is to provide an energy-saving device and method for staged charging and depressurization of coal gasification furnace coal feeding device, which is more efficient, energy-saving and environmentally friendly, and can effectively reduce the configuration scale of coal lock compressor and reduce energy consumption loss.

[0054] To enable those skilled in the art to better understand the technical solutions provided by the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] For details, please refer to Figures 1-2 The present invention provides an energy-saving device for staged charging and depressurization of a coal gasifier, comprising two coal feeding systems, a gasifier, a coal lock charging and depressurization pipeline system, a programmable valve group, and a control system.

[0056] There are two coal feeding systems, each consisting of a coal bunker 100, a coal chute 200, a coal lock 300, and a transition chamber 400 connected in sequence. The coal bunker 100 is used to temporarily store raw coal. The coal chute 200 is an inclined coal conveying channel that transports coal from the coal bunker to the coal lock 300. The coal lock 300 is a sealed pressure vessel, connected at the top to the coal chute and at the bottom to the transition chamber 400. The transition chamber 400 is an intermediate buffer chamber, and its outlet is connected to the gasifier inlet via a pipeline (the outlets of the transition chambers of both coal feeding systems are connected to the same gasifier inlet). Specifically, the first coal chute 210 and the second coal chute 220 are connected to the outlet of the coal bunker 100 via flanges or direct welding. One end of the first coal lock 310 and the second coal lock 320 is connected to the first coal chute 210 and the second coal chute 220, respectively, and the other end is connected to the transition chamber 400. The first coal feeding chute 210 and the second coal feeding chute 220 are equipped with a coal lock upper valve 330 and a coal lock lower valve 340. When the first coal lock 310 and the second coal lock 320 need to be filled with coal, the coal lock is usually depressurized to atmospheric pressure first, and then the coal lock upper valve 330 is opened. The raw coal falls from the coal bunker 100 through each coal feeding chute 200 into the corresponding coal lock 300 by gravity. When the coal lock 300 is full of coal, the coal lock upper valve 330 at the top is closed, and then its pressure is increased to the same level as that of the gasifier through the pressurization pipeline. After that, the coal lock lower valve 340 at the bottom of the coal lock 300 is opened, and the coal is discharged under gravity.

[0057] The gasifier inlet receives dry coal powder from the transition chamber 400, and generates syngas (mainly composed of CO and H2) through a high-temperature gasification reaction inside.

[0058] The coal lock pressurization and depressurization pipeline system adopts a graded pressure buffer and pipeline integration design, specifically including: multiple coal lock gas buffer pipes with different pressure levels, multiple pressurization branches connecting the coal lock 300 to the multiple coal lock gas buffer pipes with different pressure levels, and multiple depressurization branches. All coal lock gas buffer pipes are sealed tanks used to store coal lock gas at different pressures.

[0059] The programmable valve group is installed on each coal lock 300 and the coal lock pressure relief pipeline system.

[0060] The control system is connected to the programmable valve group and is configured to control each coal lock 300 to alternately perform coal feeding, pressurization, material discharge to the transition bin 400, and pressure relief operations. The control system can use a PLC controller to control the opening and closing sequence and degree of the programmable valve group through a preset program, so as to realize the alternating operation of the two coal feeding systems.

[0061] This invention provides an energy-saving device for staged pressurization and depressurization of a coal gasification furnace coal feeding system. The control system coordinates two coal feeding systems to alternately perform coal feeding, pressurization, discharge, and depressurization operations. During coal feeding, the upper valve 330 of the coal lock 300 of the corresponding coal feeding system is opened. Coal from the coal bunker 100 falls into the coal lock 300 via the coal feeding chute 200 until the set coal loading amount is reached. The upper valve 330 of the coal lock is then closed, completing the coal feeding operation. During pressurization, the control system sequentially opens the coal lock gas buffer pipe and the corresponding pressurization valve in the pressurization branch according to the pressure levels from low to high, using the coal lock gas stored in the buffer pipe to pressurize the coal lock. When the coal lock pressure reaches equilibrium with the pressure of the corresponding coal lock gas buffer pipe, the pressurization valve corresponding to that level is closed, and the coal lock gas buffer pipe and pressurization valve of the next level are opened until pressurization is complete. During the discharge operation, the lower valve 340 of coal lock 300 is opened, and the coal inside the coal lock falls into the transition chamber 400 under gravity, and then enters the gasifier through the pipeline. During the pressure relief operation, after discharge, the control system sequentially opens the coal lock gas buffer pipes and corresponding pressure relief valves in the pressure relief branches according to the pressure levels from high to low. Residual coal lock gas in the coal lock is discharged into the corresponding coal lock gas buffer pipe through the pressure relief valve. When the coal lock pressure is reduced to a level equal to the pressure of the corresponding coal lock gas buffer pipe, the pressure relief valve corresponding to that level is closed, and the coal lock gas buffer pipe and pressure relief valve of the next level are opened until pressure relief is complete. The coal lock returns to normal pressure, preparing for the next round of coal feeding. After one coal feeding system completes discharge, the control system automatically switches to another coal feeding system and repeats the above steps.

[0062] In the above setup, a staged pressurization and depressurization design allows for the collection of gas according to pressure levels during depressurization, while also serving as a recirculating source of pressurized gas. Compared to traditional single-stage pressurization and depressurization devices (which directly discharge coal lock gas or use high-pressure gas for pressurization), this device reduces the consumption of externally supplied high-pressure gas, making it more efficient, energy-saving, and environmentally friendly. It can effectively reduce the scale of coal lock gas compressor configuration and decrease energy loss.

[0063] This solution also includes an ejector 500, a low-pressure coal lock gas scrubber 1000, a scrubbing separator 1100, a gas holder 1200, and a compressor 1300. This pathway is responsible for collecting, purifying, and recovering the coal gas discharged during the coal lock depressurization process, which is crucial for safety, environmental protection, and economic efficiency.

[0064] The suction port of ejector 500 is connected to the top of coal lock 300 via ejector valve 510, and is used to continuously draw residual gas from coal lock 300 after coal lock 300 is empty and depressurized. The outlet of ejector 500 is sequentially connected to low-pressure coal lock gas scrubber 1000, scrubber separator 1100, gas holder 1200 and compressor 1300.

[0065] After the coallock gas is mixed with the driving medium (such as low-pressure nitrogen) in the ejector 500, the ejector, under the action of low-pressure nitrogen, carries out the residual coallock gas and light coal dust. The gas, after initial settling, first enters the low-pressure coallock gas scrubber 1000, where it is further washed with water to remove fine dust and cool the gas. Then, the gas enters the scrubbing separator 1100 for gas-liquid separation to remove entrained moisture. The purified coal gas enters the gas holder 1200 for storage and recovery, reducing the amount of coal dust and tar carried out by the coallock gas, while also reducing the effective gas loss and environmental problems caused by directly venting residual coallock gas. Finally, the compressor 1300 pressurizes the low-pressure coal gas in the gas holder 1200 so that it can be returned to the process system for reuse (for example, sent to the crude coal gas main for recovery). The coal lock gas stored in the gas holder 1200 is compressed and pressurized by the compressor 1300 to a pressure slightly higher than that of the coal gas main, and then sent to the crude coal gas main for external distribution. The coal lock gas in the gas holder is washed before being compressed by the compressor to perform work, which greatly reduces the amount of dust and oil it carries, reduces wear and blockage of equipment and pipelines such as compressors, reduces maintenance frequency, and effectively reduces maintenance costs.

[0066] Based on the above specific embodiments, multiple coal lock gas buffer pipes of different pressure levels include an intermediate coal lock gas buffer pipe 600, a primary coal lock gas buffer pipe 700, a secondary coal lock gas buffer pipe 800, and a tertiary coal lock gas buffer pipe 900 arranged in parallel. The intermediate coal lock gas buffer pipe 600 is also connected to the inlet of the compressor 1300. All of the above coal lock gas buffer pipes can be tubular containers.

[0067] The programmable valve assembly includes: a coal lock upper valve 330 and a coal lock lower valve 340 installed on each coal lock 300; a pressurizing valve connected in series in the pressurizing branches of the intermediate coal lock gas buffer pipe 600, the primary coal lock gas buffer pipe 700, the secondary coal lock gas buffer pipe 800, and the tertiary coal lock gas buffer pipe 900; and valves connected in series in the depressurization branches of the intermediate coal lock gas buffer pipe 600, the primary coal lock gas buffer pipe 700, the secondary coal lock gas buffer pipe 800, and the tertiary coal lock gas buffer pipe 900. Specifically, a fourth depressurization valve 610 is installed on the depressurization branch of the intermediate coal lock gas buffer pipe 600. A third depressurization valve 710 and a primary pressurization valve 720 are installed on the depressurization branch and the pressurizing branch of the primary coal lock gas buffer pipe 700, respectively. A second depressurization valve 810 and a second pressurization valve 820 are installed on the depressurization branch and the pressurization branch of the secondary coal lock gas buffer pipe 800, respectively. The pressure relief branch and the pressure charging branch of the three-stage coal lock gas buffer pipe 900 are respectively equipped with a primary pressure relief valve 910 and a tertiary pressure charging valve 920. In addition, a gas holder inlet valve 1210 is connected in series between the washing separator 1100 and the gas holder 1200, and a gas holder outlet valve 1220 is connected in series between the gas holder 1200 and the compressor 1300. A compressor valve 1310 is connected in series between the intermediate coal lock gas buffer pipe 600 and the compressor 1300. The pressure relief branch also includes a branch connecting the coal lock 300 to the outside, on which a fifth-stage pressure relief valve 1010 is connected in series.

[0068] All of the above valves are pneumatically or electrically controlled, and support remote adjustment by the control system.

[0069] The programmable valves of the pressurization and depressurization pipeline can realize staged pressurization and depressurization, dividing the coal lock pressure into several pressure levels. From high to low, the coal lock gas is depressurized by the tertiary coal lock gas buffer pipe 900, the secondary coal lock gas buffer pipe 800, the primary coal lock gas buffer pipe 700, the intermediate coal lock gas buffer pipe 600, and the low-pressure coal lock gas scrubber 1000. From low to high, the coal lock is pressurized by the primary coal lock gas buffer pipe 700, the secondary coal lock gas buffer pipe 800, the tertiary coal lock gas buffer pipe 900, and the gasifier pressure.

[0070] Compared to existing technologies, this project utilizes coal lock depressurization gas and gasifier self-pressurization to achieve coal lock pressurization, reduce the impact of inert medium introduction on the effective gas content of gasifier outlet gas, and increase the processing load of carbon dioxide gas recovery in the purification section.

[0071] This solution also provides an energy-saving method for staged pressure charging and depressurization of a coal gasifier feeding device. Applying the energy-saving device for staged pressure charging and depressurization of the coal gasifier feeding device in the above specific embodiments, the energy-saving method includes:

[0072] In step S100, after the first coal lock 310 of the two coal locks 300 is empty and depressurized, the control system closes all valves on the coal lock charging and depressurization pipeline system. The ejector valve 510 of the ejector 500 is normally open to ensure continuous extraction of residual gas from the coal lock and prevent gas from escaping. The upper coal lock valve 330 and the coal feeding chute valve 230 of the coal lock 300 are opened to add coal to the first coal lock 310; after the coal is added to the full material, the coal feeding chute valve 230 and the upper coal lock valve 330 are closed in sequence.

[0073] Step S200: Perform multi-stage pressurization on the first coal lock 310. Specifically, this includes: opening the primary pressurization valve 720 of the primary coal lock gas buffer pipe 700 to pressurize the first coal lock 310 until it reaches pressure equal to that of the primary coal lock gas buffer pipe 700 (approximately 2.5 MPa, pressurization time 120 s), and then closing the primary pressurization valve 720; opening the secondary pressurization valve 820 to pressurize the first coal lock 310 until it reaches pressure equal to that of the secondary coal lock gas buffer pipe 800 (approximately 3.3 MPa, pressurization time 120 s), and then closing the secondary pressurization valve 820. Pressurization valve 820; open the third pressurization valve 920 to pressurize the first coal lock 310 to balance the pressure with the pressure of the third-stage coal lock gas buffer pipe 900 (approximately 3.9 MPa, pressurization time 120 s), and close the third pressurization valve 920 after balancing; open the first coal lock 310 and the balancing valve 410 to balance the pressure of the first coal lock 310 with the pressure of the transition chamber 400 (approximately 4.3 MPa, pressurization time 10 s), and close the balancing valve 410 after balancing to complete the coal lock pressurization process.

[0074] Step S300: Open the coal lock lower valve 340. Depending on the operation of the gasifier, coal from the first coal lock 310 can be fed into the gasifier in batches. After the first coal lock 310 is empty, close the coal lock lower valve 340.

[0075] Step S400: Perform multi-stage pressure relief on the first coal lock 310. Specifically, this includes: opening the primary pressure relief valve 910 to relieve the pressure of the first coal lock 310 until it is balanced with the pressure of the third-stage coal lock gas buffer pipe 900 (approximately 3.9 MPa, pressure relief time 120 s), and then closing the primary pressure relief valve 910; opening the secondary pressure relief valve 810 to relieve the pressure of the first coal lock 310 until it is balanced with the pressure of the second-stage coal lock gas buffer pipe 800 (approximately 3.3 MPa, pressure relief time 120 s), and then closing the secondary pressure relief valve 810; and opening the tertiary pressure relief valve 710 to relieve the pressure of the first coal lock 310 until it is balanced with the pressure of the first-stage coal lock gas buffer pipe 900. Pressure is balanced in pipe 700 (approximately 2.5 MPa, pressure relief time 120 s). After balance, the third pressure relief valve 710 is closed. The fourth pressure relief valve 610 is opened to release the pressure of the first coal lock 310 to balance with the pressure of the intermediate coal lock gas buffer pipe 600 (approximately 0.9 MPa, pressure relief time 100 s). After balance, the fourth pressure relief valve 610 is closed. The fifth pressure relief valve 1010 is opened to release the pressure of the first coal lock 310 to near atmospheric pressure (e.g., below 0.05 MPa), and then the fifth pressure relief valve 1010 is closed, completing the pressure relief process for the first coal lock 310. Return to step S100.

[0076] The coal lock gas, after being depressurized five times, is sent to the low-pressure coal lock gas scrubber 1000. The low-pressure coal gas is used for water scrubbing to remove impurities such as coal powder and tar from the coal lock gas. After scrubbing, the coal lock gas undergoes gas-liquid separation in the scrubbing separator 1100. The separated coal lock gas is then sent to the gas holder 1200 for buffering.

[0077] After a large amount of coal dust is removed by the bag filter, the coal lock gas from ejector 500 is sent to compressor 1300.

[0078] The coal lock gas from gas holder 1200 and ejector 500 is pressurized by compressor 1300 and then connected to the crude coal gas pipeline network, and sent to the downstream section for synthesis reaction.

[0079] During the process of one of the two coal locks 300 adding coal to the gasifier in step S300, the control system controls the other of the two coal locks 300 to simultaneously execute the pressurization process in step S200; the two coal locks 300 work alternately to ensure a stable coal supply to the gasifier.

[0080] The coal lock is pressurized and depressurized in stages to add coal to the gasifier. This includes primary depressurization gas going to the tertiary coal lock gas buffer pipe 900, secondary depressurization gas going to the secondary coal lock gas buffer pipe 800, tertiary depressurization gas going to the primary coal lock gas buffer pipe 700, quaternary depressurization gas going to the intermediate coal lock gas buffer pipe 600, quintuple depressurization gas going to the low-pressure coal lock gas scrubbing system, and depressurization residual gas going to the low-pressure coal lock gas scrubbing system via ejector 500. Primary pressurization gas comes from the primary coal lock gas buffer pipe 700, secondary pressurization gas comes from the secondary coal lock gas buffer pipe 800, tertiary pressurization gas comes from the tertiary coal lock gas buffer pipe 900, quaternary pressurization gas comes from the transition chamber 400, and the low-pressure coal lock gas, after scrubbing, goes to the gas holder 1200. The coal lock gas in the gas holder is then sent to the coarse coal gas main pipe for recovery via compressor 1300.

[0081] Based on the above specific embodiment, between steps S100 and S200, step S210 is further included to perform a leak test on the closed coal lock valve 330. The tertiary pressurization valve 920 of the three-stage coal lock gas buffer pipe 900 is opened to briefly inject pressurized gas into the first coal lock 310, and then closed. The pressure of the first coal lock 310 is monitored. If the pressure drop is lower than a threshold value within a set time, the leak test is qualified, and the coal bunker coal-to-coal-lock process is completed. The brief pressurization time can be set to 5 seconds, and the threshold value can be 50 kPa.

[0082] Based on the above specific embodiment, between steps S300 and S400, step S410 is also included, which involves leak testing the closed coal lock lower valve 340: opening the four-stage pressure relief valve 610 to briefly release the pressure inside the first coal lock 310 before closing it, monitoring the pressure of the first coal lock 310, and if the pressure rise is lower than the threshold within a set time, the leak test is qualified, and the coal lock coal feeding process to the gasifier is completed. The brief pressure release time can be set to 5 seconds, and the threshold can be 50 kPa.

[0083] The beneficial effects of the technical solution provided by this invention include:

[0084] 1. The coal feeding system is equipped with two coal locks (300). Coal is fed alternately from the two coal locks (300) into the transition chamber (400) to ensure stable and continuous operation of the gasifier. During operation, the two coal locks alternately feed coal; when one coal lock is operating, the other coal lock depressurizes and feeds coal.

[0085] 2. By coupling the buffer pipe of the coal lock charging and depressurization pipeline system with the gas holder 1200, multi-stage charging and depressurization of the coal lock, coal lock gas recycling, and coal lock gas recovery were successfully realized. The coal lock gas was used to achieve stable alternating charging and depressurization of the two coal locks, which reduced the coal lock charging and depressurization cycle time, effectively increased the gasifier operating load, reduced the waste of effective gas and environmental pollution caused by coal lock gas discharge, reduced the configuration scale of coal lock gas compressor, and reduced energy consumption loss.

[0086] 3. Under full furnace operation, the pressure of the gasifier is used to pressurize the coal lock, which reduces the amount of inert medium used, increases the effective gas content at the gasifier gas outlet, reduces the processing pressure of the downstream section, maintains the pressure of the inert medium pipeline network, and is conducive to the stable operation of other systems of the gasifier.

[0087] 4. Install a low-pressure coal lock gas scrubber 1000 and a scrubbing separator 1100 to reduce the content of coal powder, tar and other media in the coal lock gas, and reduce the frequency of inspection and maintenance of equipment and pipelines such as compressors.

[0088] 5. An ejector 500 is installed and continuously driven by low-pressure nitrogen, which effectively reduces the content of toxic and harmful gases such as CO in the environment, solves the problem of residual gas escaping when adding coal to the coal bunker, and ensures on-site safety.

[0089] In summary, this invention fully utilizes the four-stage pressurization and five-stage depressurization of the coal lock gas, effectively improving the coal adding efficiency of the coal lock, enhancing the stability of the gasifier under high load operation, extending the service life of the equipment, reducing maintenance costs, reducing energy consumption, and eliminating environmental pressure from external emissions, thus providing strong technical support for the efficient and safe production of the coal chemical industry.

[0090] In addition, the washed medium causes less wear on pipelines, equipment, and valves, reduces maintenance difficulty, and has a simple equipment structure, enabling stable and continuous coal feeding to the gasifier. Furthermore, this invention can be adapted to change the equipment's operating capacity based on actual conditions, allowing multiple gasifiers to be used in parallel, which is beneficial for large-scale engineering.

[0091] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0092] In the description of this application, "multiple" means two or more. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0093] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0094] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A coal gasification furnace coal charging device energy-saving device with grading pressure charging and discharging, characterized in that, The coal gasification furnace coal charging device comprises two coal charging systems, a gasification furnace, a coal lock pressure charging and discharging pipeline system, a program-controlled valve group and a control system. Each of the coal charging systems comprises a coal bunker (100), a coal charging chute (200), a coal lock (300) and a transition bunker (400) connected in sequence. The coal lock pressure charging and discharging pipeline system comprises a plurality of coal lock gas buffer pipes of different pressure levels, a plurality of pressure charging branches and a plurality of pressure discharging branches connected to the coal lock (300) and the coal lock gas buffer pipes of different pressure levels. The program-controlled valve group is arranged on each of the coal locks (300) and the coal lock pressure charging and discharging pipeline system. The control system is connected with the program-controlled valve group and is configured to control each of the coal locks (300) to alternately perform coal charging, pressure charging, transition bunker (400) discharging and pressure discharging operations.

2. The energy saving device of claim 1, wherein, The coal gasification furnace coal charging device further comprises an ejector (500), a low-pressure coal lock gas scrubber (1000), a scrubbing separator (1100), a gas tank (1200) and a compressor (1300). The suction port of the ejector (500) is connected to the top of the coal lock (300) through an ejector valve (510). The outlet of the ejector (500) is sequentially connected to the low-pressure coal lock gas scrubber (1000), the scrubbing separator (1100), the gas tank (1200) and the compressor (1300).

3. The energy saving device of claim 2, wherein, The coal lock gas buffer pipes of different pressure levels comprise an intermediate coal lock gas buffer pipe (600), a first-stage coal lock gas buffer pipe (700), a second-stage coal lock gas buffer pipe (800) and a third-stage coal lock gas buffer pipe (900) arranged in parallel, and the intermediate coal lock gas buffer pipe (600) is connected to the inlet of the compressor (1300). The program-controlled valve group comprises a coal lock upper valve (330) and a coal lock lower valve (340) arranged on each of the coal locks (300), a pressure charging valve arranged in each of the pressure charging branches, and a valve arranged in each of the pressure discharging branches.

4. An energy-saving method for grading pressure charging and discharging of a coal gasifier coal charging device, characterized in that, The energy-saving method comprises the following steps: In step S100, when one of the two coal locks (300) is empty and pressure discharging is completed, the control system closes all the valves on the coal lock pressure charging and discharging pipeline system, the ejector valve (510) of the ejector (500) is always open, the coal lock upper valve (330) of the coal lock and the coal charging chute valve (230) are opened, and coal is charged into the coal lock; after the coal charging is completed, the coal charging chute valve (230) and the coal lock upper valve (330) are closed in sequence; In step S200, the coal lock (300) is subjected to multi-stage pressure charging; In step S300, the coal lock lower valve (340) of the coal lock (300) is opened, the coal in the coal lock is discharged into the transition bunker (400) and then into the gasification furnace, and after the transition bunker (400) is emptied, the coal lock lower valve (340) is closed; In step S400, the coal lock (300) is subjected to multi-stage pressure discharging, and the process returns to step S100. In step S400, the coal lock (300) is subjected to multi-stage pressure discharging, and the process returns to step S100. In the process of performing step S300 to add coal to the gasifier in one of the two coal locks (300), the control system controls the other of the two coal locks (300) to perform the pressure charging process of step S200 synchronously; the two coal locks (300) work alternately.

5. The energy saving method according to claim 4, characterized in that, The step S200 comprises: sequentially passing a primary pressure charging valve (720) of a primary coal lock gas buffer pipe (700), a secondary pressure charging valve (820) of a secondary coal lock gas buffer pipe (800), and a tertiary pressure charging valve (920) of a tertiary coal lock gas buffer pipe (900) to stage-by-stage increase the pressure of the coal lock (300) to balance with the pressure of the corresponding level of the coal lock gas buffer pipe; finally, opening the balance valve (410) of the transition bin (400) to balance the pressure and then closing.

6. The energy saving method of claim 4, wherein, The step S400 comprises: sequentially passing a primary pressure releasing valve (910) of a tertiary coal lock gas buffer pipe (900), a secondary pressure releasing valve (810) of a secondary coal lock gas buffer pipe (800), and a tertiary pressure releasing valve (710) of a primary coal lock gas buffer pipe (700) to stage-by-stage release the pressure of the coal lock (300) to balance with the pressure of the corresponding level of the coal lock gas buffer pipe; then releasing to the pressure of the intermediate coal lock gas buffer pipe (600) through a fourth pressure releasing valve (610) of the intermediate coal lock gas buffer pipe (600), and finally releasing to the pressure near the normal pressure through a fifth pressure releasing valve (1010).

7. The energy saving method of claim 4, wherein, Further comprising a step S210 between the step S100 and the step S200, which is to leak test the closed coal lock upper valve (330): opening the tertiary pressure charging valve (920) of the tertiary coal lock gas buffer pipe (900), briefly charging pressure gas into the coal lock (300), then closing, monitoring the pressure of the coal lock (300), and if the pressure drop value is lower than a threshold value within a set time, the leak test is qualified.

8. The energy saving method of claim 4, wherein, Further comprising a step S410 between the step S300 and the step S400, which is to leak test the closed coal lock lower valve (340): opening the fourth pressure releasing valve (610), briefly releasing the pressure in the coal lock (300), then closing, monitoring the pressure of the coal lock (300), and if the pressure rise value is lower than a threshold value within a set time, the leak test is qualified.

9. The energy saving method according to claim 7 or 8, characterized in that, The set time is 5s, and the threshold value is 50kPa.

10. The energy saving method of claim 4, wherein, In the step S200, the specific pressure of multi-stage pressure charging is: primary pressure charging to 2.5MPa±0.3MPa, secondary pressure charging to 3.3MPa±0.3MPa, tertiary pressure charging to 3.9MPa±0.3MPa, and finally balancing with the transition bin (400) to 4.3Mpa±0.3MPa; And / or, in the step S400, the specific pressure of multi-stage pressure releasing is: primary pressure releasing to 3.9MPa±0.3MPa, secondary pressure releasing to 3.3MPa±0.3MPa, tertiary pressure releasing to 2.5MPa±0.3MPa, fourth pressure releasing to 0.9MPa±0.3MPa, and finally releasing to below 0.05MPa.

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