Multi-condition heating furnace combustion stabilization system and method

Abstract

The application discloses a multi-working-condition heating furnace combustion stabilizing system and method, wherein the acid gas of each device is mixed into an acid gas desulfurization tower through first to fourth adjusting valves for desulfurization; after the dry gas is refined, part of the dry gas is sent to a downstream device, and the other part of the dry gas is mixed into a first fuel gas distribution tank through a seventh adjusting valve and a No. 3 density instrument, and is mixed with pipe network fuel gas through a No. 2 density instrument and an eighth adjusting valve; a No. 1 density instrument monitors the density of the mixed fuel gas; the seventh and eighth adjusting valves cooperatively control the pressure and the density in the tank; through acid gas collection, desulfurization, dry gas refining and fuel gas mixing control, the parameters of the first fuel gas distribution tank are stabilized; the application eliminates the safety hazards of the heating furnace caused by pipe network fluctuation, reduces the comprehensive energy consumption of the device, has high automation degree, has a flexible process flow and is suitable for various oil refining devices with dry gas desulfurization units.

Description

Technical Field

[0001] This invention relates to the field of operation control technology for oil refining and chemical equipment, specifically to a combustion stabilization system and method for multi-condition heating furnaces. It is particularly suitable for diesel hydrogenation and wax oil hydrogenation refining units equipped with dry gas desulfurization units, achieving dual stable control of the pressure and composition of the fuel gas system in the heating furnace, and ensuring safe, stable, and efficient combustion in the heating furnace. Background Technology

[0002] The existing refinery's boiler fuel gas mainly comes from non-recoverable refinery gas produced by various production units such as C1 / C2 separation units, C3 / C4 separation units, alkylation units, and wax oil cracking units. This refinery gas is collected through processes such as flare recovery and then connected to the public fuel gas pipeline network. Due to significant differences in the process flow and operating conditions of each gas-producing unit, the mixed fuel gas in the public fuel gas pipeline network fluctuates drastically in terms of composition, pressure, and calorific value. This directly affects the combustion stability of the boiler, causing large fluctuations in the boiler outlet medium temperature, which in turn leads to substandard refinery product quality. Under extreme conditions, sudden changes in fuel gas pressure or composition can also cause boiler shutdown or even flash explosions, seriously threatening the safe operation of the unit. At the same time, the existing refinery's self-produced desulfurized dry gas is not effectively utilized, and the boiler fuel gas is completely dependent on the public fuel gas pipeline network, resulting in high external fuel gas consumption, high overall energy consumption of the unit, and a lack of energy-saving optimization design. Summary of the Invention

[0003] This invention provides a combustion stabilization system for a multi-condition heating furnace and a corresponding control method. The core technical solution is to add a dedicated connection process system between the desulfurized dry gas produced by the unit and the public fuel gas pipeline network. One-way valves, regulating valve groups, orifice flow meters, densitometers and other instruments are installed on the connecting pipeline. Through the series control of the flow meters and regulating valve groups, the flow rate of the desulfurized dry gas supplemented to the pipeline network fuel gas is precisely adjusted. Combined with the real-time monitoring of multiple densitometers, dual closed-loop control of fuel gas density and pressure is achieved.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: The present invention provides a combustion stabilization system for a multi-condition heating furnace, comprising an acid gas desulfurization tower, a first liquid separator, an absorption tower, a first water cooler, a first coalescer, a pressure-stabilizing and deliquencing tank, and a first fuel gas liquid separator; It also includes a first regulating valve, a second regulating valve, a third regulating valve, a fourth regulating valve, a fifth regulating valve, a sixth regulating valve, a seventh regulating valve, an eighth regulating valve, a density meter No. 1, a density meter No. 2, a density meter No. 3, and several pipelines; Diesel hydrorefining sour gas is connected to the gas phase inlet of the sour gas desulfurization tower via Pipeline 1 and the first regulating valve. Wax oil hydrotreating sour gas is connected to the gas phase inlet of the sour gas desulfurization tower via Pipeline 2 and the second regulating valve. Wax oil hydrocracking sour gas is connected to the gas phase inlet of the sour gas desulfurization tower via Pipeline 3 and the third regulating valve. Second-stage diesel hydrocracking sour gas is connected to the gas phase inlet of the sour gas desulfurization tower via Pipeline 4 and the fourth regulating valve. Lean amine liquid pump is connected via Pipeline 5. The line is connected to the liquid phase inlet of the acid gas desulfurization tower via the fifth regulating valve. The gas phase outlet of the acid gas desulfurization tower is connected to the inlet of the first liquid separator via pipeline number six. The outlet of the first liquid separator is connected to the bottom inlet of the absorption tower via pipeline number seven. The first coalescer is connected to the upper liquid phase inlet of the absorption tower via pipeline number eight, which is equipped with a delivery pump. The gas phase outlet of the absorption tower is connected to the inlet of the first water cooler via pipeline number nine. The outlet of the first water cooler is connected to the inlet of the pressure-stabilized descaling tank E via pipeline number ten.

[0005] Preferably, the first outlet of the pressure-stabilized dehydrator is connected to the downstream device via pipeline No. 11 and regulating valve No. 6. The second outlet of the pressure-stabilized dehydrator is connected to the pipeline connecting to density meter No. 3 via pipeline No. 12 and regulating valve No. 7. It is also connected to the inlet of density meter No. 1 and fuel gas separator in sequence. Pipeline No. 12 is connected to fuel gas separator No. 2 via pipeline No. 15 between regulating valve No. 7 and fuel gas separator No. 1.

[0006] Preferably, the public fuel gas pipeline is connected to the inlet of the first fuel gas separator via pipeline No. 13, density meter No. 2, and regulating valve No. 8. The regulating valve No. 8 is linked with the sensor on the first fuel gas separator to achieve closed-loop pressure control.

[0007] Preferably, the No. 1 density meter is located at the top of the first fuel gas separator. The No. 1 density meter, the No. 2 density meter, the No. 3 density meter, and the seventh regulating valve are all connected by signal. The outlet of the first fuel gas separator is connected to the fuel gas inlet of the heating furnace through the No. 14 pipeline. The first fuel gas separator is a closed pressure tank.

[0008] Preferably, the acid gas desulfurization tower is a packed tower or a plate tower, in which the lean amine liquid and the mixed acid gas are arranged in counter-current contact. The flow rate of the lean amine liquid is individually controlled by the fifth regulating valve to achieve precise control of the hydrogen sulfide removal efficiency.

[0009] Preferably, the lean oil and the desulfurized dry gas in the absorption tower have a counter-contact structure. The lean oil is continuously supplied by the first coalescer and is used to remove the C5+ heavy components in the desulfurized dry gas. A demister is installed at the gas phase outlet of the absorption tower.

[0010] Preferably, the pressure-stabilizing dehydration tank is equipped with a baffle dehydration structure inside, and the tank body is equipped with a pressure detection instrument. Its internal pressure is controlled by the sixth regulating valve and the seventh regulating valve in concert to achieve stable output of dry gas pressure.

[0011] This invention provides a method for stabilizing combustion in a multi-condition heating furnace based on the aforementioned system, comprising the following steps: Step 1: The acid gas from the diesel hydrorefining process is sent to the gas phase inlet of the acid gas desulfurization tower via pipeline No. 1 and the first regulating valve. Step 2: The acidic gas from the wax oil hydrogenation treatment is sent to the gas phase inlet of the acidic gas desulfurization tower via pipeline No. 2 and the second regulating valve; Step 3: The acidic gas from the wax oil hydrocracking process is sent to the gas phase inlet of the acidic gas desulfurization tower via pipeline No. 3 and the third regulating valve; Step 4: The acid gas from the second-stage diesel hydrocracking is sent to the gas phase inlet of the acid gas desulfurization tower via pipeline No. 4 and the fourth regulating valve. Step 5: The mixed acid gas enters the bottom of the acid gas desulfurization tower and comes into countercurrent contact with the lean amine liquid whose flow rate is controlled by the No. 5 pipeline and the No. 5 regulating valve, thereby removing hydrogen sulfide from the mixed acid gas.

[0012] Preferably, it also includes subsequent refining and conveying steps: Step 6: The desulfurized dry gas from the top of the acid gas desulfurization tower enters the first liquid separator via pipeline No. 6 to remove the residual liquid phase carried in the dry gas. Step 7: The dry gas from the first separator enters the bottom of the absorption tower through pipeline No. 7, and comes into countercurrent contact with the lean oil from the first coalescer and pipeline No. 8, absorbing the heavy components in the dry gas. Step 8: The dry gas at the top of the absorption tower enters the first water cooler through pipeline No. 9 to be cooled to below 40°C, and then enters the pressure stabilizing and dehydration tank E through pipeline No. 10 to complete pressure stabilization and secondary dehydration. Step 9: Part of the dry gas in the pressure-stabilizing dehydration tank is sent to the downstream unit via pipeline No. 11 and regulating valve No. 6, and the other part is sent to the first fuel gas separator via pipeline No. 12, density meter No. 3 and regulating valve No. 7. Step 10: Fuel gas from the public fuel gas pipeline enters the first fuel gas separator through pipeline No. 13, density meter No. 2, and regulating valve No. 8. It is mixed with the self-produced desulfurized dry gas in the first fuel gas separator. The density of the mixed fuel gas is monitored in real time by density meter No. 1. The flow rate of the self-produced dry gas is adjusted by regulating valve No. 7 to achieve a stable density of the mixed fuel gas. The mixed fuel gas is then sent to the heating furnace through pipeline No. 14.

[0013] Preferably, the feed ratio of each acid gas is adjusted by the first, second, third, and fourth regulating valves to keep the dry gas density at the outlet of the pressure-stabilizing dehydration tank E, as monitored by the third density meter, constant. When the pressure of the public fuel gas pipeline decreases, the seventh regulating valve automatically increases its opening to supplement the self-produced dry gas. When the pipeline pressure increases, the eighth regulating valve automatically decreases its opening to reduce the feed amount of pipeline fuel gas, thus working together to maintain the pressure stability in the first fuel gas separator. When the composition of the pipeline fuel gas fluctuates, the self-produced desulfurized dry gas is used as a buffer medium to reduce the impact of fuel gas composition fluctuations on the combustion system of the heating furnace. The entire control process is automated through the DCS system.

[0014] Beneficial effects: It effectively addresses the pressure and composition fluctuations in the public fuel gas pipeline network. The self-produced desulfurized dry gas can quickly replenish pressure and act as a stabilizing buffer, eliminating safety hazards such as furnace fluctuations, shutdowns, and even flash explosions, ensuring stable operation of the unit. Using the self-produced desulfurized dry gas as supplementary fuel for the furnace reduces fuel gas consumption from the public pipeline network, lowering the unit's fuel consumption and overall energy consumption, thus improving production economy. The flexible process design allows for flexible switching of the self-produced dry gas delivery path according to the actual operating conditions of the unit, adapting to various production needs such as start-up, shutdown, and load adjustments. Real-time monitoring by a density meter and linkage control with regulating valves enable automated and precise control of fuel gas density and pressure, reducing manual intervention and improving the stability and production efficiency of the furnace operation. The self-produced dry gas, after multiple refining processes, has high purity and stable composition, improving furnace combustion efficiency, reducing exhaust pollutant emissions, and providing both energy-saving and environmental benefits. Attached Figure Description

[0015] Figure 1 This is a block diagram illustrating the principle of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] Invention content / principle: This invention provides a combustion stabilization system for a multi-condition heating furnace and a corresponding control method. The core technical solution is to add a dedicated connection process system between the desulfurized dry gas produced by the unit and the public fuel gas pipeline network. One-way valves, regulating valve groups, orifice flow meters, densitometers and other instruments are installed on the connecting pipeline. Through the series control of the flow meters and regulating valve groups, the flow rate of the desulfurized dry gas supplemented to the pipeline network fuel gas is precisely adjusted. Combined with the real-time monitoring of multiple densitometers, dual closed-loop control of fuel gas density and pressure is achieved.

[0019] The system of this invention mainly consists of an acid gas desulfurization tower A, a first liquid separator B, an absorption tower C, a first water cooler D, a first coalescer D1, a pressure-stabilizing and deliquescing tank E, a first fuel gas liquid separator G, and other equipment, as well as first to eighth regulating valves ah, densitometers k, i, and j (numbers one to three), and several dedicated pipelines. Acid gas from each unit flows through corresponding pipelines and regulating valves into the acid gas desulfurization tower A for hydrogen sulfide removal. After desulfurization, the dry gas sequentially passes through the first liquid separator B for deliquescing, the absorption tower C for counter-current contact with lean oil supplied by the first coalescer D1 to remove heavy components, and the first water cooler D for pressure reduction. After the temperature and pressure stabilized dehydration tank E dehydrates, it forms a self-produced dry gas with stable composition. Part of the dry gas is sent to the downstream unit, and the other part is merged into the first fuel gas separator G of the public fuel gas pipeline network through a dedicated pipeline. The public fuel gas enters the first fuel gas separator G through the second density meter i and the eighth regulating valve h. After mixing with the self-produced dry gas, the density of the mixed fuel gas is monitored in real time by the first density meter k. The seventh regulating valve g and the eighth regulating valve h work together to stabilize the density and pressure of the fuel gas in the first fuel gas separator G, and finally supply fuel gas with constant properties to the heating furnace.

[0020] The method of this invention completes the processes of acid gas collection, desulfurization, dry gas purification, dry gas diversion, and fuel gas mixing and regulation in steps. It uses the first to fourth regulating valves ad to adjust the feed ratio of each acid gas to ensure the stability of the self-produced dry gas composition. It uses densitometers k, i, and j to monitor the fuel gas density at different nodes in real time. Combined with the linkage control of the seventh regulating valve g and the eighth regulating valve h, it adapts to various operating conditions such as pressure and composition fluctuations in the public fuel gas pipeline network, and finally achieves stable operation of the heating furnace fuel gas system.

[0021] Example 1: The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is based on a combined diesel hydrotreating and wax oil hydrotreating unit in an oil refinery. This unit is equipped with a dry gas desulfurization unit, and the heater is the core heating equipment of the unit. The raw material and fuel gas system is severely affected by fluctuations in the public pipeline network. The system and method of the present invention are used for technical transformation. The specific implementation steps are as follows: System Setup and Pipeline Connection: The multi-condition heating furnace combustion stabilization system as described in claim 1 is constructed. Dedicated pressure pipelines numbered one to fifteen are fabricated. The first regulating valve a, the second regulating valve b, the third regulating valve c, and the fourth regulating valve d are respectively connected to the acid gas output terminals of the diesel hydrorefining, wax oil hydrotreating, wax oil hydrocracking, and second-stage diesel hydrocracking units, and to the gas phase inlet of the acid gas desulfurization tower A. The fifth regulating valve e is connected to the lean amine liquid pump and to the liquid phase inlet of the acid gas desulfurization tower A. The gas phase outlet of the acid gas desulfurization tower A is connected to the inlet of the first separator B via pipeline number six. The outlet of the first separator B is connected to the bottom inlet of the absorption tower C via pipeline number seven. The first coalescer D1 is connected to the upper liquid phase inlet of the absorption tower C via pipeline number eight. The gas phase outlet of the absorption tower C is connected to the inlet of the first water cooler D via pipeline number nine. The outlet of the first water cooler D is connected to the inlet of the first water cooler D via pipeline number ten. The inlet of the pressure-stabilized dehydration tank E is connected; the first outlet of the pressure-stabilized dehydration tank E is connected to the downstream dry gas utilization unit via pipeline No. 11 and regulating valve No. 6, and the second outlet is connected to the inlet of the first fuel gas separator G via pipeline No. 12, density meter No. 3, and regulating valve No. 7, and pipeline No. 12 is connected to the second fuel gas separator G via pipeline No. 15 after regulating valve No. 7; the public fuel gas pipeline is connected to the inlet of the first fuel gas separator G via pipeline No. 13, density meter No. 2, and regulating valve No. 8, and density meter No. 1 is installed on the top of the first fuel gas separator G, and the bottom outlet is connected to the fuel gas inlet of the heating furnace via pipeline No. 14; check valves and orifice plate flow meters are added to the connecting pipelines, all regulating valves are electric regulating valves, all density meters are online gas density meters, and all equipment, instruments and devices are connected to the DCS system signal to realize automated monitoring and control.

[0022] Collection and desulfurization of acidic gas: Open the first regulating valve a, the second regulating valve b, the third regulating valve c, and the fourth regulating valve d. Adjust the opening of each regulating valve according to the production load of the unit. The acidic gas from diesel hydrorefining, wax oil hydrotreatment, wax oil hydrocracking, and second-stage diesel hydrocracking is transported to the gas phase inlet of acidic gas desulfurization tower A through the corresponding pipelines in a preset ratio. Open the lean amine liquid pump and the fifth regulating valve e. Control the opening of the fifth regulating valve e to transport the lean amine liquid to the liquid phase inlet of acidic gas desulfurization tower A through pipeline No. 5. The lean amine liquid and the mixed acidic gas are in countercurrent contact in acidic gas desulfurization tower A to fully remove hydrogen sulfide from the mixed acidic gas. The desulfurized dry gas is discharged from the top of acidic gas desulfurization tower A. The hydrogen sulfide removal efficiency is ≥99%.

[0023] The refining process of the self-produced desulfurized dry gas: The desulfurized dry gas discharged from the top of the acid gas desulfurization tower A enters the first liquid separator B through pipeline No. 6. Through gravity settling and the action of baffles in the first liquid separator B, the liquid phase residue carried in the dry gas is removed. The residue is periodically discharged from the bottom drain port of the first liquid separator B. The dry gas after liquid removal in the first liquid separator B enters the bottom of the absorption tower C through pipeline No. 7. It comes into countercurrent contact with the lean oil from the first coalescer D1 and pipeline No. 8 in the absorption tower C. The lean oil fully absorbs the C5+ heavy components in the dry gas, improving the purity of the dry gas. The refined dry gas at the top of the absorption tower C enters the first water cooler D through pipeline No. 9. The dry gas temperature is reduced to 35°C by circulating water cooling. The cooled dry gas enters the pressure stabilizing and deliquencing tank E through pipeline No. 10. The pressure of the dry gas is stabilized and the liquid is removed in the second stage, ensuring that the dry gas pressure is stable at 0.8MPa and that there are no liquid droplets carried.

[0024] The self-produced desulfurized dry gas is distributed and transported as follows: The sixth regulating valve f is opened and its opening degree is adjusted to send a portion of the refined dry gas in the pressure-stabilized desulfurization tank E to the downstream dry gas utilization unit via pipeline eleven, meeting the dry gas requirements of other production stages of the unit; at the same time, the seventh regulating valve g is opened, and the density meter j monitors the density of the dry gas at the outlet of the pressure-stabilized desulfurization tank E in real time. The orifice plate flow meter monitors the dry gas flow rate in real time and transmits it to the DCS system. The opening degree of the first regulating valve a, the second regulating valve b, the third regulating valve c, and the fourth regulating valve d is adjusted through the DCS system to change the feed ratio of each acid gas, so that the dry gas density monitored by the density meter j is kept constant at 0.6 kg / m³, ensuring the stability of the composition of the self-produced desulfurized dry gas.

[0025] Fuel gas mixing and precise control: With the eighth regulating valve h open, fuel gas from the public fuel gas pipeline is transported via pipeline thirteen. Density meter i monitors the density of the pipeline fuel gas in real time and transmits the data to the DCS system. After pressure regulation by the eighth regulating valve h, the pipeline fuel gas enters the first fuel gas separator G. Self-produced desulfurized dry gas enters the first fuel gas separator G via pipeline twelfth, density meter j, and the seventh regulating valve g, where it is fully mixed with the pipeline fuel gas. Density meter k monitors the density of the mixed fuel gas in real time. If the density deviates from the preset value by 0.7 kg / m³, the DCS system, combined with the flow data from the orifice plate flow meter, automatically adjusts the opening of the seventh regulating valve g to change the supplementary flow rate of the self-produced dry gas, achieving stable control of the mixed fuel gas density. Simultaneously, the eighth regulating valve h is linked with the pressure detection instrument of the first fuel gas separator G to adjust the feed rate of the pipeline fuel gas in real time, stabilizing the pressure in the first fuel gas separator G at 0.75 MPa.

[0026] Adaptive control under multiple operating conditions: When the pressure of the public fuel gas pipeline drops below 0.7MPa, the DCS system receives the pressure signal and automatically increases the opening of the seventh regulating valve g to increase the replenishment of self-produced desulfurized dry gas, quickly raising the pressure in the first fuel gas separator G to the preset value; when the pipeline pressure rises above 0.8MPa, the DCS system automatically decreases the opening of the eighth regulating valve h to reduce the feed rate of the pipeline fuel gas and maintain the pressure stability in the first fuel gas separator G; when the composition of the pipeline fuel gas fluctuates, causing the density change monitored by the second density meter i to exceed ±0.05kg / m³, the self-produced desulfurized dry gas is continuously and stably replenished to the first fuel gas separator G as a stabilizing buffer medium to reduce the impact of fuel gas composition fluctuations on the properties of the mixed fuel gas, ensuring that the density of the mixed fuel gas monitored by the first density meter k is always within the preset range; the mixed and stable fuel gas is continuously transported to the heating furnace through the fourteenth pipeline to ensure the combustion stability of the heating furnace, and the temperature fluctuation of the heating furnace outlet medium is controlled within ±2℃.

[0027] In this embodiment, all equipment adopts the standard equipment of the oil refining industry, the pipeline is made of carbon steel to meet the requirements of pressure bearing and corrosion resistance, the one-way valve adopts the swing one-way valve to prevent fuel gas backflow, the orifice plate flow meter selects the standard orifice plate, the entire system operates stably after the modification, and can be adapted to various production conditions such as start-up and shutdown of oil refining unit, load adjustment, and fluctuation of public pipeline network for a long time, with a fault-free operation time of ≥8000 hours.

[0028] In summary, this invention can accurately address various fluctuations in the public fuel gas pipeline network. When the pipeline pressure decreases, the self-produced desulfurized dry gas can be quickly integrated into the unit's fuel system via the seventh regulating valve g, increasing the pressure inside the first fuel gas separator G. When the pipeline pressure increases, the feed rate of the pipeline fuel gas is reduced via the eighth regulating valve h to maintain system pressure stability. When the composition of the pipeline fuel gas fluctuates, the self-produced desulfurized dry gas, with its composition precisely controlled and kept constant, can act as a stable buffer medium, significantly reducing the impact of fuel gas composition fluctuations on the internal fuel system of the unit, completely eliminating safety hazards such as furnace fluctuations, shutdowns, furnace extinguishing, and even flash explosions, ensuring safe production of the unit. This invention uses the unit's self-produced desulfurized dry gas as supplementary fuel gas for the furnace, effectively replacing part of the fuel gas supply from the public fuel gas pipeline network, significantly reducing the amount of fuel gas used from the public pipeline network, reducing the unit's fuel consumption, and thus reducing the overall energy consumption of the refining unit and improving production economy. Simultaneously, the optimized fuel gas system can flexibly switch processes according to the actual operating conditions of the unit, adapting to multiple production needs. The process flow system design of this invention is highly flexible. It can flexibly switch the delivery path of the self-produced dry gas through the sixth regulating valve f and the seventh regulating valve g, according to the actual operating conditions of the refining unit. The dry gas can be sent to downstream units or supplemented to the heating furnace fuel system, adapting to various production conditions such as unit start-up and shutdown, load adjustment, and pipeline fluctuations. This invention achieves precise closed-loop control of fuel gas density and pressure through real-time online monitoring by density meters k, i, and j (numbers 1 to 3) and automated linkage control by regulating valves ah (numbers 1 to 8). The entire system has a high degree of automation, requiring minimal manual intervention. This improves the stability of the heating furnace operation and reduces the labor intensity of operators. Furthermore, the connection methods of each device and instrument are simple, facilitating the technical transformation and widespread application of existing equipment. The self-produced dry gas of this invention undergoes multiple refining processes, including desulfurization in acid gas desulfurization tower A, removal of heavy components in absorption tower C and first coalescer D1. The dry gas has high purity and stable composition. When it is used as supplementary fuel gas in the heating furnace, it can improve the combustion efficiency of the heating furnace and reduce pollutant emissions in the combustion exhaust gas, thus achieving both energy saving and environmental protection benefits.

[0029] Finally, it should be noted that the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A combustion stabilization system for a multi-condition heating furnace, characterized in that, It includes an acid gas desulfurization tower (A), a first liquid separator (B), an absorption tower (C), a first water cooler (D), a first coalescer (D1), a pressure-stabilizing liquid separator (E), and a first fuel gas liquid separator (G). It also includes a first regulating valve (a), a second regulating valve (b), a third regulating valve (c), a fourth regulating valve (d), a fifth regulating valve (e), a sixth regulating valve (f), a seventh regulating valve (g), an eighth regulating valve (h), a density meter (k), a density meter (i), a density meter (j), and several pipelines; Diesel hydrorefining sour gas is connected to the gas phase inlet of the sour gas desulfurization tower (A) via pipeline No. 1 and first regulating valve (a). Wax oil hydrotreating sour gas is connected to the gas phase inlet of the sour gas desulfurization tower (A) via pipeline No. 2 and second regulating valve (b). Wax oil hydrocracking sour gas is connected to the gas phase inlet of the sour gas desulfurization tower (A) via pipeline No. 3 and third regulating valve (c). Second-stage diesel hydrocracking sour gas is connected to the gas phase inlet of the sour gas desulfurization tower (A) via pipeline No. 4 and fourth regulating valve (d). Lean amine liquid pump is connected to the gas phase inlet of the sour gas desulfurization tower (A) via pipeline No. 5 and fifth regulating valve. Valve (e) is connected to the liquid phase inlet of the acid gas desulfurization tower (A). The gas phase outlet of the acid gas desulfurization tower (A) is connected to the inlet of the first liquid separator (B) via pipeline No.

6. The outlet of the first liquid separator (B) is connected to the bottom inlet of the absorption tower (C) via pipeline No.

7. The first coalescer (D1) is connected to the upper liquid phase inlet of the absorption tower (C) via pipeline No. 8 with a transfer pump. The gas phase outlet of the absorption tower (C) is connected to the inlet of the first water cooler (D) via pipeline No.

9. The outlet of the first water cooler (D) is connected to the inlet of the pressure-stabilizing desliming tank (E) via pipeline No.

10.

2. The multi-condition heating furnace combustion stabilization system according to claim 1, characterized in that, The first outlet of the pressure-stabilized dehydrator (E) is connected to the downstream device via pipeline eleven and regulating valve six (f). The second outlet of the pressure-stabilized dehydrator (E) is connected to the pipeline connecting to density meter three (j) via pipeline twelve and regulating valve seven (g), and is sequentially connected to density meter one (k) and the inlet of the first fuel gas separator (G). Pipeline twelve is connected to the second fuel gas separator via pipeline fifteen between regulating valve seven (g) and the first fuel gas separator (G).

3. The multi-condition heating furnace combustion stabilization system according to claim 1 or 2, characterized in that, The public fuel gas pipeline is connected to the inlet of the first fuel gas separator (G) via pipeline No. 13, density meter No. 2 (i), and regulating valve No. 8 (h). The regulating valve No. 8 (h) is linked with the sensor on the first fuel gas separator (G) to achieve closed-loop pressure control.

4. The multi-condition heating furnace combustion stabilization system according to claim 2, characterized in that, Density meter No. 1 (k) is located on top of the first fuel gas separator (G). Density meter No. 1 (k), density meter No. 2 (i), density meter No. 3 (j), and the seventh regulating valve (g) are all connected by signal. The outlet of the first fuel gas separator (G) is connected to the fuel gas inlet of the heating furnace through pipeline No.

14. The first fuel gas separator (G) is a closed pressure tank.

5. The multi-condition heating furnace combustion stabilization system according to claim 1, characterized in that, The acid gas desulfurization tower (A) is a packed tower or a plate tower. The lean amine liquid and the mixed acid gas are arranged in counter-current contact inside the tower. The flow rate of the lean amine liquid is individually controlled by the fifth regulating valve (e) to achieve precise control of the hydrogen sulfide removal efficiency.

6. The multi-condition heating furnace combustion stabilization system according to claim 1, characterized in that, The lean oil and desulfurized dry gas in the absorption tower (C) have a counter-current contact structure. The lean oil is continuously supplied by the first coalescer (D1) to remove C5+ heavy components from the desulfurized dry gas. A demister is installed at the gas phase outlet of the absorption tower (C).

7. The multi-condition heating furnace combustion stabilization system according to claim 1, characterized in that, The pressure-stabilizing dehydration tank (E) is equipped with a baffle dehydration structure and a pressure detection instrument. Its internal pressure is controlled by the sixth regulating valve (f) and the seventh regulating valve (g) to achieve stable output of dry gas pressure.

8. A method for stabilizing combustion in a multi-condition heating furnace based on the system described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: The diesel hydrorefining acid gas is sent to the gas phase inlet of the acid gas desulfurization tower (A) via pipeline No. 1 and the first regulating valve (a); Step 2: The acidic gas from the wax oil hydrogenation treatment is sent to the gas phase inlet of the acidic gas desulfurization tower (A) via pipeline No. 2 and the second regulating valve (b); Step 3: The acidic gas from the hydrocracking of wax oil is sent to the gas phase inlet of the acidic gas desulfurization tower (A) via pipeline No. 3 and the third regulating valve (c); Step 4: The acid gas from the second-stage diesel hydrocracking is sent to the gas phase inlet of the acid gas desulfurization tower (A) via pipeline No. 4 and the fourth regulating valve (d); Step 5: The mixed acid gas enters the bottom of the acid gas desulfurization tower (A) and comes into countercurrent contact with the lean amine liquid whose flow rate is controlled by pipeline No. 5 and regulating valve No. 5 (e) to remove hydrogen sulfide from the mixed acid gas.

9. The method for stabilizing combustion in a multi-condition heating furnace according to claim 8, characterized in that, This also includes subsequent refining and transport steps: Step 6: The desulfurized dry gas from the top of the acid gas desulfurization tower (A) enters the first liquid separator (B) through pipeline No. 6 to remove the residual liquid phase carried in the dry gas; Step 7: The dry gas from the first separator (B) enters the bottom of the absorption tower (C) through pipeline No. 7, and comes into countercurrent contact with the lean oil from the first coalescer (D1) and pipeline No. 8, absorbing the heavy components in the dry gas; Step 8: The dry gas at the top of the absorption tower (C) enters the first water cooler (D) through pipeline No. 9 to be cooled to below 40°C, and then enters the pressure stabilizing and dehydration tank (E) through pipeline No. 10 to complete pressure stabilization and secondary dehydration. Step 9: Part of the dry gas in the pressure stabilizing and dehydrating tank (E) is sent to the downstream unit via pipeline No. 11 and regulating valve No. 6 (f), and the other part is sent to the first fuel gas separator (G) via pipeline No. 12, density meter No. 3 (j) and regulating valve No. 7 (g). Step 10: The fuel gas from the public fuel gas pipeline enters the first fuel gas separator (G) through pipeline No. 13, density meter No. 2 (i), and regulating valve No. 8 (h). It is mixed with the self-produced desulfurized dry gas in the first fuel gas separator (G). The density of the mixed fuel gas is monitored in real time by density meter No. 1 (k). The replenishment flow of self-produced dry gas is adjusted by regulating valve No. 7 (g) to achieve a stable density of the mixed fuel gas. The mixed fuel gas is sent to the heating furnace through pipeline No.

14.

10. The method for stabilizing combustion in a multi-condition heating furnace according to claim 9, characterized in that, The feed ratio of each acid gas is adjusted by the first regulating valve (a), the second regulating valve (b), the third regulating valve (c), and the fourth regulating valve (d) to control the dry gas density at the outlet of the pressure-stabilizing dehydration tank (E) monitored by the third density meter (j) to remain constant. When the pressure of the public fuel gas pipeline decreases, the seventh regulating valve (g) automatically increases its opening to supplement the self-produced dry gas. When the pipeline pressure increases, the eighth regulating valve (h) automatically decreases its opening to reduce the feed amount of pipeline fuel gas, thus working together to maintain the pressure stability in the first fuel gas separator (G). When the composition of the pipeline fuel gas fluctuates, the self-produced desulfurized dry gas is used as a buffer medium to reduce the impact of fuel gas composition fluctuations on the combustion system of the heating furnace. The entire control process is automated through the DCS system.

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