Production process for improving coal gas quality of circular internal heat type high temperature pyrolysis carbonization furnace

Abstract

The present application relates to a kind of production processes for improving the quality of circular internal heat type high temperature pyrolysis carbonization furnace gas, coal is sent into carbonization furnace, and the generated gas is sent into gas purification system;Gas is dedusted by dust collector, cooled by cooler, enters water removal filter after oil removal by tar separator, and nitrogen enrichment screen is built-in in water removal filter, absorbs nitrogen, improves gas concentration, and completes preliminary purification;After being processed by compressor, hydration reactor, cooler and decomposer, purification is completed.The carbonization furnace of the present application uses oxygen-rich as gasification agent, improves carbonization degree;The purpose of two-stage dry distillation is to make gas as gas heat carrier and improve gas quality.After purification treatment, the water content of the produced gas is greatly reduced, and the combustion efficiency is greatly improved.Coke oven gas purification and purification technology has the advantages of low cost, low energy consumption, small pollution and high product added value, and increases enterprise benefit.

Description

Technical Field

[0001] This invention relates to the field of coal coking processing, and is applied to the coal coking treatment in the coking, magnesium smelting, coal, and steel industries; in particular, it relates to a production process for improving the quality of gas from a circular internally heated high-temperature pyrolysis carbonization furnace. Background Technology

[0002] Currently, many small-scale semi-coke enterprises are formed by merging private kilns. They use outdated design standards, lack design margins, and have little room for improvement. The semi-coke gas they produce has low calorific value and low purity, resulting in poor prospects for thermal power generation. In most cases, it is not used as fuel for power generation but is instead sent to supporting or downstream enterprises as low-calorific-value fuel.

[0003] According to the report "Environmental Upgrading and Transformation of Deep Purification and Regeneration System for Coke Oven Gas," the dry gas purification process currently used in my country is imperfect, with unsatisfactory removal of impurities from blast furnace gas and an inability to guarantee the degree of purification. Furthermore, molecular sieves have a narrow application range, and drastic temperature changes can lead to problems such as caking and embrittlement. Patent CN201220070822.3 discloses a dry dust removal and dechlorination composite device for blast furnace gas. This device connects a generator set and a pressure reducing valve in series. The dust collector contains dechlorination particles, desulfurization particles, deammonium particles, and hygroscopic particles, simultaneously removing chlorine, sulfur, and ammonia from the blast furnace gas. While the process described in the published patent can indeed produce relatively pure gas, the gas volume and calorific value are affected by various particle types. These particles cannot be efficiently regenerated, resulting in high operating costs. The report "Advances in Carbon Monoxide Separation and Purification Technology" reports on the current development of gas purification technology. The main difficulty in separating and purifying blast furnace gas is the separation of gas and nitrogen. Commonly used gas separation methods include pressure swing adsorption, membrane separation, cryogenic separation, and molecular sieve separation. Molecular sieve separation is one of the most promising purification technologies. Patent CN201410651179.7 discloses a method for purifying coke oven gas. After heat exchange, the coke oven gas enters a dehydration tower and then returns to a tar recovery tower to precipitate tar. After methanol washing, it enters a buffer tank. This technology separates ammonia, tar, and methanol through heat exchange, water removal, and condensation. However, methanol is a volatile organic compound, and the washing process results in a significant loss of detergent, which cannot be regenerated. This is essentially the same as traditional purification processes.

[0004] In view of this, a production process for improving the quality of gas from a circular, internally heated high-temperature pyrolysis carbonization furnace was designed to overcome the above technical problems. After purification, the water content of the produced gas is significantly reduced, and the combustion efficiency is greatly improved. This makes it an ideal choice for the secondary utilization of coke oven gas in coking enterprises. Summary of the Invention

[0005] The purpose of this invention is to provide a production process for improving the quality of gas from a circular internally heated high-temperature pyrolysis carbonization furnace.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] The production process for improving the gas quality of a circular internally heated high-temperature pyrolysis carbonization furnace is as follows:

[0008] 1) Coal is fed into the carbonization furnace through the feeding system. It passes through the drying and preheating section, the medium-temperature dry distillation section and the high-temperature dry distillation section of the carbonization furnace from top to bottom and then enters the pyrolysis carbonization chamber for ignition. Oxygen-enriched gas is used as the combustion-supporting gas.

[0009] 2) The coal is softened in the medium-temperature dry distillation section and dry distilled in the high-temperature dry distillation section. The resulting coal gas is sent to the coal gas purification system through the gas collection pipe.

[0010] 3) The gas first enters the dust collector through the gas collection pipe for dust removal, and then enters the cooler for cooling, so that the gas temperature is reduced to 50-90℃ before entering the tar separator; the oil-removed gas enters the water filter, which has a built-in nitrogen enrichment screen to absorb nitrogen, increase the gas concentration, and complete the preliminary purification.

[0011] 4) The pre-purified coal gas first enters the first-stage compressor, and the gas flow rate and pressure are increased to 0.5-0.9 MPa before entering the hydration reactor. Then it enters the first-stage cooler for cooling, and the outlet temperature of the first-stage cooler is 0-3℃.

[0012] 5) The gas cooled by the primary cooler is compressed again by the secondary compressor, reacted in the hydration reactor, and cooled by the secondary cooler before entering the primary decomposer; the outlet pressure of the secondary compressor is 1.6-2.6 MPa, and the outlet temperature of the secondary cooler is -10 to 0℃;

[0013] 6) The coal gas from the first-stage decomposer is compressed by the third-stage compressor, cooled by the third-stage heat exchanger, and finally enters the second-stage decomposer for decomposition, thus completing the coal gas purification. The outlet pressure of the third-stage compressor is 0.1-0.6 MPa, and the outlet temperature of the third-stage heat exchanger is 15-30℃.

[0014] In step 1) above, oxygen enrichment involves drying the air and then sending it through an air compressor into a filter. The filter is equipped with a nitrogen enrichment screen to absorb nitrogen from the air and increase the oxygen concentration to 26-35%.

[0015] The method for preparing the nitrogen enrichment sieve is as follows: 0.1 mmol Ce(NO3)3·6H2O and 0.2 mmol Cl2H 10FeO4 is dissolved in acetone and stirred at room temperature for 10-90 min. Then, it is poured into a Teflon reactor and reacted at 140-220℃ for 12-18 h. After the reaction is complete, it is washed three times alternately with acetone and distilled water, and then dried at 80℃ for 12-18 h. The synthesized product is poured into a crucible and calcined at 300℃ for 1-5 h with argon gas in a tube furnace. Then, it is cooled to room temperature to obtain the precursor. The precursor is mixed with 1000-2000 mesh fly ash in an equal proportion and then immersed in 30% liquid alkali. The mixture is stirred and ground thoroughly. The mixture is placed in a crucible and melted at 550-850℃ with nitrogen gas in a tube furnace. After cooling to room temperature, it is ultrasonically treated for 2 hours and then placed in a Teflon reactor for hydrothermal treatment at 80℃ for 12 hours. It is thoroughly washed with deionized water until the pH of the supernatant reaches <10. Then, it is dried at 90℃ for 12 h and molecular sieves of 20-80 mesh or larger are selected.

[0016] The reaction temperature of the hydration reactor is 3-9℃, and the pressure is 0.5-0.9 MPa.

[0017] The temperature of the primary decomposer is 50-80℃, and the release of combustible organic components reaches 80-90%.

[0018] The temperature of the medium-temperature dry distillation section is 450-650℃, and the temperature of the high-temperature dry distillation section is 650-1000℃.

[0019] The nitrogen content in the preliminarily purified coal gas from step 3) above is 8-25%, and the calorific value per unit coal gas is greater than or equal to 3200 kcal / Nm³. 3 .

[0020] Compared with existing technologies, the beneficial effects of this invention are:

[0021] 1) The carbonization furnace uses oxygen-enriched gasifier to improve the degree of carbonization; the purpose of two-stage dry distillation is to use coal gas as a gaseous heat carrier. The coal gas produced in high-temperature dry distillation has a high calorific value but low output. The produced coal gas can carry heat to perform preliminary pyrolysis of the material in the medium-temperature dry distillation zone, thereby increasing the gas production. The quality and quantity of coal gas from two-stage dry distillation are improved compared to single-stage dry distillation.

[0022] 2) After purification, the water content of the produced coke oven gas is greatly reduced, and the combustion efficiency is significantly improved. Coke oven gas purification and upgrading technology has advantages such as low cost, low energy consumption, low pollution, and high product added value, which increases enterprise benefits and is in line with my country's current environmental protection strategy. It is an ideal choice for the secondary utilization of coke oven gas in coking enterprises. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0025] See Figure 1 The production process for improving the gas quality of a circular internally heated high-temperature pyrolysis carbonization furnace is as follows:

[0026] 1) Coal is fed into the carbonization furnace through the feeding system. It passes through the drying and preheating section, the medium-temperature dry distillation section and the high-temperature dry distillation section of the carbonization furnace from top to bottom and then enters the pyrolysis carbonization chamber for ignition. Oxygen-enriched gas is used as the combustion-supporting gas.

[0027] 2) The coal is softened in the medium-temperature dry distillation section and dry distilled in the high-temperature dry distillation section. The resulting coal gas is sent to the coal gas purification system through the gas collection pipe.

[0028] 3) The coal gas first enters the dust collector through the gas collecting pipe for dust removal, and then enters the cooler for cooling. The cooler is an ammonia water spray cooler. The ammonia water comes into countercurrent contact with the upward coal gas through the nozzles. The coal gas releases a large amount of sensible heat, and the droplets quickly absorb heat and vaporize, reducing the coal gas temperature to 50-90℃ before entering the tar separator. The tar separator is a bag / sponge separator. When the coal gas passes through the bag / sponge, the atomized tar is trapped on the filter surface. The oil-removed coal gas enters the water filter. The water filter has a built-in nitrogen enrichment screen to absorb nitrogen, increase the coal gas concentration, and complete the preliminary purification.

[0029] 4) The pre-purified coal gas first enters the first-stage compressor, and the gas flow rate and pressure are increased to 0.5-0.9 MPa before entering the hydration reactor. Then it enters the first-stage cooler for cooling, and the outlet temperature of the first-stage cooler is 0-3℃.

[0030] 5) The gas cooled by the primary cooler is compressed again by the secondary compressor, reacted in the hydration reactor, and cooled by the secondary cooler before entering the primary decomposer; the outlet pressure of the secondary compressor is 1.6-2.6 MPa, and the outlet temperature of the secondary cooler is -10 to 0℃;

[0031] 6) The coal gas from the first-stage decomposer is compressed by the third-stage compressor, cooled by the third-stage heat exchanger, and finally enters the second-stage decomposer for decomposition, thus completing the coal gas purification. The outlet pressure of the third-stage compressor is 0.1-0.6 MPa, and the outlet temperature of the third-stage heat exchanger is 15-30℃.

[0032] Hydration Reactor Principle: Coke oven gas is mainly composed of methane, oxygen, nitrogen, and other organic gases. Methane, oxygen, and nitrogen form crystalline complexes with water molecules under low temperature and high pressure, which then combine with smaller organic molecules to form cage-like crystals. In different phase equilibrium relationships, the order in which these molecules form crystals varies. Temperature and pressure are controlled during compression and heat exchange, thereby achieving the separation of crystals with different compositions. The separated single-component crystals enter a decomposer for gas-liquid separation, completing the gas purification process.

[0033] In step 1) above, oxygen enrichment involves drying the air and then sending it through an air compressor into a filter. The filter is equipped with a nitrogen enrichment screen to absorb nitrogen from the air and increase the oxygen concentration to 26-35%.

[0034] The method for preparing the nitrogen enrichment sieve is as follows: 0.1 mmol Ce(NO3)3·6H2O and 0.2 mmol Cl2H 10 FeO4 was dissolved in acetone and stirred at room temperature for 10-90 min, then poured into a Teflon reactor and reacted at 140-220℃ for 12-18 h. After the reaction was complete, the mixture was washed three times alternately with acetone and distilled water, and then dried at 80℃ for 12-18 h. The synthesized product was poured into a crucible and calcined at 300℃ for 1-5 h in a tube furnace under argon gas, then cooled to room temperature to obtain the precursor. The precursor was mixed with 1000-2000 mesh fly ash in equal proportions and then leached with a 30% alkali solution. No, thoroughly stir and grind (the precursor will aggregate into small particles during calcination, and needs to be ground to be fully wetted by liquid alkali, grind to 1000-2000 mesh), put the mixture into a crucible, and use a tube furnace to maintain nitrogen gas at 550-850℃ to complete the melting process. After cooling to room temperature, sonicate for 2 hours, put it into a Teflon reactor for hydrothermal treatment at 80℃ for 12 hours, wash thoroughly with deionized water until the pH value of the supernatant reaches <10, and then dry at 90℃ for 12 hours, and select molecular sieves of 20-80 mesh or higher.

[0035] The reaction temperature of the hydration reactor is 3-9℃, and the pressure is 0.5-0.9 MPa.

[0036] The temperature of the primary decomposer is 50-80℃, and the release of combustible organic components reaches 80-90%.

[0037] The decomposer is a closed, atmospheric pressure container with no special internal structure. It serves as the decomposition site for hydrates. Before entering the decomposer, the hydrates are crystalline complexes. In the decomposer, water and gaseous organic matter are separated. In the first-stage decomposer, 80-90% of the combustible organic components can be decomposed from the hydrates and converted into coal gas.

[0038] The secondary decomposer serves both as a secondary decomposition unit and a buffer, with the aim of decomposing the remaining gas in the hydrate.

[0039] The intermediate-temperature carbonization section operates at 450-650℃, primarily softening the coal and initially decomposing it into crude coal gas. The high-temperature carbonization section operates at 650-1000℃, completing the carbonization process.

[0040] The temperature in the pyrolysis carbonization chamber is maintained at 900-1280℃, further condensing and releasing hydrogen. An oxygen-enriched inlet is connected to the outside of the pyrolysis carbonization chamber to introduce oxygen as a combustion aid, with a concentration of 26-35% oxygen used as a gasifying agent for combustion inside the chamber.

[0041] In step 3) above, the nitrogen enrichment screen is placed inside the water removal filter to adsorb nitrogen from the coal gas, initially increasing the coal gas concentration. The nitrogen content in the preliminarily purified coal gas is 8-25%, and the calorific value per unit coal gas is greater than or equal to 3200 kcal / Nm³. 3 This nitrogen enrichment sieve adsorbs nitrogen under high pressure conditions of 1.5–10 MPa and desorbs nitrogen under normal pressure, allowing for repeated use.

[0042] In this invention, the function of the gas compressor is to reduce the gas volume and increase the gas flow rate.

Claims

1. A production process for improving the gas quality of a circular internally heated high-temperature pyrolysis carbonization furnace, characterized in that, The process is as follows: 1) Coal is fed into the carbonization furnace through the feeding system. It passes through the drying and preheating section, the medium-temperature carbonization section and the high-temperature carbonization section of the carbonization furnace from top to bottom before entering the pyrolysis carbonization chamber for ignition. Oxygen-enriched gas is used as the combustion-supporting gas. The temperature of the medium-temperature dry distillation section is 450-650℃, the temperature of the high-temperature dry distillation section is 650-1000℃, and the temperature of the pyrolysis carbonization chamber is maintained at 900-1280℃. The oxygen enrichment process involves drying the air and then sending it through an air compressor into a filter. The filter is equipped with a nitrogen enrichment screen to absorb nitrogen from the air and increase the oxygen concentration to 26-35%. 2) The coal is softened in the medium-temperature dry distillation section and dry distilled in the high-temperature dry distillation section. The resulting coal gas is sent to the coal gas purification system through the gas collection pipe. 3) The coal gas first enters the dust collector through the gas collecting pipe for dust removal, then enters the cooler for cooling, reducing the coal gas temperature to 50-90℃ before entering the tar separator. After oil removal, the coal gas enters the water filter, which contains a nitrogen enrichment screen to absorb nitrogen, increasing the coal gas concentration and completing the preliminary purification. The nitrogen content in the preliminarily purified coal gas is 8-25%, and the calorific value per unit coal gas is greater than or equal to 3200 kcal / Nm³. 3 ; 4) The pre-purified coal gas first enters the first-stage compressor, and the gas flow rate and pressure are increased to 0.5-0.9 MPa before entering the hydration reactor. Then it enters the first-stage cooler for cooling, and the outlet temperature of the first-stage cooler is 0-3℃. 5) The gas cooled by the primary cooler is compressed again by the secondary compressor, reacted in the hydration reactor, and cooled by the secondary cooler before entering the primary decomposer; the outlet pressure of the secondary compressor is 1.6-2.6 MPa, and the outlet temperature of the secondary cooler is -10 to 0℃; 6) The coal gas from the first-stage decomposer is compressed by the third-stage compressor, cooled by the third-stage heat exchanger, and finally enters the second-stage decomposer for decomposition, thus completing the coal gas purification; the outlet pressure of the third-stage compressor is 0.1-0.6 MPa, and the outlet temperature of the third-stage heat exchanger is 15-30℃. The method for preparing the nitrogen enrichment sieve is as follows: 0.1 mmol Ce(NO3)3·6H2O and 0.2 mmol C 12 H 10 FeO4 is dissolved in acetone and stirred at room temperature for 10-90 min. Then it is poured into a Teflon reactor and reacted at 140-220℃ for 12-18 h. After the reaction is complete, it is washed three times alternately with acetone and distilled water, and then dried at 80℃ for 12-18 h. The synthesized product is poured into a crucible and calcined at 300℃ for 1-5 h with argon gas in a tube furnace. Then it is cooled to room temperature to obtain the precursor. The precursor is mixed with 1000-2000 mesh fly ash in an equal proportion and then immersed in 30% liquid alkali. The mixture is stirred and ground thoroughly. The mixture is placed in a crucible and melted at 550-850℃ with nitrogen gas in a tube furnace. After cooling to room temperature, it is ultrasonically treated for 2 hours and then placed in a Teflon reactor for hydrothermal treatment at 80℃ for 12 hours. It is thoroughly washed with deionized water until the pH of the supernatant reaches < 10. Then it is dried at 90℃ for 12 h and molecular sieves of 20-80 mesh or larger are selected. The temperature of the primary decomposer is 50-80℃, and the release of combustible organic components reaches 80-90%.

2. The production process for improving the gas quality of a circular internally heated high-temperature pyrolysis carbonization furnace according to claim 1, characterized in that, The reaction temperature of the hydration reactor is 3-9℃, and the pressure is 0.5-0.9Mpa.

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