A method of controlling resistance in a negative pressure gas system

Abstract

This invention relates to the field of coal gas purification technology, and more particularly to a method for controlling the resistance of a negative pressure coal gas system. This invention involves systematic technical analysis and research based on theory and production practice, avoiding the need for post-processing cleaning of the primary cooler, electrostatic precipitator, and gas pipelines. It breaks through the methods and approaches for controlling and handling the resistance of negative pressure coal gas systems involved in the field of coal gas purification, employing daily monitoring and operational control of process parameters for the negative pressure coal gas system, daily resistance prediction and process cleaning of the negative pressure coal gas system, and emergency response plans and procedures for the negative pressure coal gas system. This system, applied to negative pressure coal gas systems in coal gas purification, can maintain the long-term stability of the negative pressure coal gas system's resistance, safeguarding production. This invention integrates daily control, resistance prediction, advance cleaning operations, and online cleaning operations, maintaining the long-term stable operation of the negative pressure coal gas system's resistance.

Description

Technical Field

[0001] This invention relates to the field of coal gas purification technology, and in particular to a method for controlling the resistance of a negative pressure coal gas system. Background Technology

[0002] In the coking and gas purification systems, the gas blower is the "heart" of the entire system. The resistance of the negative pressure gas system is a key indicator of how well this "heart" is functioning, determining whether the entire coking and gas purification system can operate normally and stably.

[0003] Both domestic and international coal gas purification systems exhibit a phenomenon where, after several years of operation or even just a few months, negative pressure coal gas pipelines experience high resistance and highly unstable operation, requiring frequent cleaning of the primary cooler and electrostatic precipitator to maintain stable resistance. There is no good solution to the problem of resistance in negative pressure gas systems. Over time, the resistance in negative pressure gas systems has deteriorated to varying degrees, leading to blockages and other issues. Each coking plant's gas purification system constantly adopts different measures to address these problems based on its own specific circumstances. Some resort to shutting down production for cleaning or replacing blocked pipes, while others replace the horizontal tube bundles of the primary cooler to resolve blockages. Still others handle various pipe and equipment blockages online. Each coking plant is trying to find suitable solutions for its own operating conditions. Some of these attempts have resulted in serious accidents, such as coke oven venting and fires, and the technology has been kept secret from external parties. There is no universal rule suitable for every coking plant's negative pressure gas pipeline. With the continuous upgrading of gas purification equipment both domestically and internationally, the trend towards larger coke ovens has become the norm, placing increasingly stringent requirements on the stability of negative pressure gas systems in gas purification devices. However, no systematic analysis has been conducted to determine the root causes of various resistance issues.

[0004] Due to the special nature of the coal gas purification process, pipelines and equipment need to operate continuously year-round without time for maintenance and cleaning. Once a blockage occurs, it cannot be cleaned online, causing the blockage to become increasingly serious until it affects the transportation of the entire coal gas system before it is addressed. Sometimes, it even leads to the negative pressure coal gas system failing to operate normally and threatening production before attention is paid to it.

[0005] The three existing methods for cleaning the primary cooler are all reactive, only cleaning the primary cooler when it experiences high resistance. Each method has its own drawbacks. The hot ammonia water cleaning technique requires the hot ammonia water temperature to be above 70℃. However, the temperature of the circulating ammonia water in the gas purification process of the upper stage of the primary cooler using ammonia water separation tank emulsion spraying is relatively low, especially in winter when the circulating ammonia water temperature is around 60℃. Cleaning the primary cooler with hot ammonia water does not achieve the desired effect. Steam cleaning of the primary cooler takes a long time, and a large amount of steam condensate enters the condensate during cleaning, causing the primary cooler temperature to exceed the standard. This is especially impossible in summer. Long-term steam cleaning of the primary cooler with high-temperature steam will strip some of the tar vapor hanging on the outside of the heat exchange tube bundle into asphalt, which will form on the outer surface of the tube bundle and affect the heat exchange efficiency of the primary cooler. Hot washing oil cleaning technology is currently a better cleaning technology, and it is used in every gas purification operation area. This technology is suitable when the primary cooler is not too clogged. However, because hot washing oil has strong solubility, it can cause the primary cooler tube bundle to leak after cleaning. When steam is introduced into the water circuit of the primary cooler during cleaning, it can cause the rubber gasket of the tube box cover to age and leak easily.

[0006] The resistance of the horizontal tube primary cooler, electrostatic precipitator, blower, and connected gas pipelines in a negative pressure system must be kept stable. In cases of abnormal resistance, corresponding countermeasures and measures must be taken to control the system resistance. Maintaining stable production operation of the negative pressure gas system is essential. Simultaneously, a stable negative pressure gas system can significantly reduce the load on the refrigeration unit, reduce the power consumption of the gas blower, prevent large amounts of naphthalene from being carried into subsequent processes, reduce the number of final cooling cleaning cycles thus avoiding benzene loss, extend the service life of the horizontal tube primary cooler, and reduce production costs.

[0007] The existing methods and measures for solving the resistance of negative pressure gas pipelines are all reactive solutions. They do not completely eradicate or prevent the root causes of blockages in the negative pressure gas system. In particular, there are no effective countermeasures in case of abnormalities in the negative pressure gas pipeline, which puts production in a passive situation. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, the present invention provides a method for controlling the resistance of a negative pressure gas system, which is applied to a negative pressure gas purification system and can stabilize the resistance of the negative pressure gas system in the long term, ensuring stable and smooth production.

[0009] To achieve the above objectives, the present invention employs the following technical solution:

[0010] A method for controlling the resistance of a negative pressure gas system, specifically including:

[0011] I. Process parameters for daily control of negative pressure gas systems

[0012] 1. Control the process parameters of the horizontal tube primary cooler, electrostatic precipitator, blower system, condensate system, circulating water system, and cryogenic water system:

[0013] The gas resistance of the horizontal tube primary cooler is less than 1 kPa, and the gas outlet temperature is 18–22°C.

[0014] The resistance of the electrostatic precipitator is less than 1 kPa, and the voltage is maintained at 40,000 to 10,000 volts to collect tar.

[0015] The gas pipeline drain pipes at the inlet and outlet of the blower system and the drain pipe of the blower body are unobstructed;

[0016] The condensate flow rate in the upper section of each primary cooler in the condensate system shall not be less than 30 m³ / s. 3 / h, the lower section condensate flow rate is not less than 80m³ / h. 3 / h, the light tar content in the lower spray solution is 10% to 30%;

[0017] The inlet temperature of the circulating water system shall not be lower than 26℃ in winter and not higher than 32℃ in summer.

[0018] The inlet temperature of the low-temperature water system shall not be lower than 14℃ in winter and not higher than 16℃ in summer.

[0019] 2. Control the flow rate and pressure of circulating ammonia water and high-pressure ammonia water:

[0020] The pressure of the circulating ammonia water sent to the coking plant is maintained above 0.4 MPa, and the pressure of the high-pressure ammonia water pump is below 2.5 MPa.

[0021] 3. Control the blower system suction, inlet suction, and temperature when the gas volume is low.

[0022] When the gas volume is low, reduce the gas suction in front of the blower system and the gas suction in front of the primary cooler while ensuring the coking suction.

[0023] Maintain the gas outlet temperature within a reasonable range by adjusting the inlet temperature or flow rate of the low-temperature water and circulating water.

[0024] 4. Control the process operating parameters of the horizontal tube primary cooler during the winter surplus hot water supply period.

[0025] The inlet temperature of circulating water shall be controlled to be no lower than 26℃, and the inlet temperature of low-temperature water shall be no lower than 14℃.

[0026] II. Resistance Prediction and Cleaning of Daily Negative Pressure Gas Systems

[0027] 1. Predict the resistance of the negative pressure gas system to determine the cleaning method and frequency:

[0028] When the resistance of the horizontal tube primary cooler is stable, the primary cooler should be cleaned every 3 to 6 days; the electrostatic precipitator should be cleaned with steam every 3 months; all drainage pipes of the gas pipeline should be cleaned every 12 hours; and the outlet gas pipeline of the blower system, as well as the related drainage pipes and the main body drainage pipe, should be cleaned every 6 hours.

[0029] 2. Perform routine resistance purging of the negative pressure gas system and determine the results:

[0030] 1) Routinely clean the condensate system of the upper and lower sections of the horizontal tube primary cooler with hot ammonia water and hot washing oil, and determine the results;

[0031] A. Process of cleaning the horizontal tube primary cooler with hot ammonia water:

[0032] a. Close the gas valve at the outlet of the horizontal tube primary cooler and stop the operation of the primary cooler;

[0033] b. Close the inlet and outlet valves of the primary cooler circulating water, the inlet and outlet valves of the cryogenic water, and drain the water from the primary cooler circulating water and cryogenic water pipelines and heat exchange tubes.

[0034] c. Stop the spraying of condensate in the upper and lower sections of the primary cooler;

[0035] d. Switch the upper and lower section condensate outlets to the temporary cleaning tank;

[0036] e. Open the upper section ammonia water cleaning valve. When the upper section condensate flows smoothly from the first temporary water seal tank into the cleaning temporary tank, open the upper section ammonia water cleaning valve fully.

[0037] f. Use a temporary cleaning pump to send the cleaned-up condensate to a mechanized ammonia clarification tank;

[0038] g. If the liquid at the outlet of the upper section of the condensate after cleaning is light yellow and oil-free, then the upper section of the primary cooler is cleaned.

[0039] h. Close the upper section ammonia water cleaning valve and open the lower section ammonia water cleaning valve. When the lower section condensate return pipeline flows smoothly into the cleaning temporary tank through the first temporary water seal tank, open the lower section ammonia water cleaning valve fully.

[0040] i. If the liquid at the outlet of the lower section of the condensate after cleaning is light yellow and oil-free, then the cleaning of the lower section of the primary cooler is complete.

[0041] j. The condensate in the upper and lower sections of the primary cooler returns to its initial state;

[0042] k. The upper section of the horizontal tube primary cooler is supplied with circulating water by adjusting the circulating water inlet valve, and the lower section of the horizontal tube primary cooler is supplied with low-temperature water by adjusting the low-temperature water inlet valve. After normal operation, the gas outlet valve of the primary cooler is opened.

[0043] B. Steam cleaning process for the horizontal tube primary cooler:

[0044] a. Clean the horizontal tube primary cooler according to the process steps a to i of cleaning the primary cooler with hot ammonia water, close the primary cooler inlet valve, introduce nitrogen into the primary cooler to eliminate the negative pressure of the primary cooler, and then open the primary cooler vent pipe to keep the pressure at normal.

[0045] b. Open the steam purging valve at the bottom of the primary cooler to introduce direct steam into the primary cooler. The steam condensate enters the first temporary water seal tank through the upper condensate return pipe and the lower condensate return pipe, and finally enters the temporary purging tank. It is then sent to the mechanized ammonia water clarification tank by the temporary purging pump.

[0046] c. When a large amount of steam is emitted from the top of the horizontal tube primary cooler, observe the quality of the liquid inside the first temporary water seal tank. When it is transparent and there is no obvious tar, the steam purging of the primary cooler is complete, and the steam purging valve is closed.

[0047] d. Perform hot ammonia cleaning and restore the primary cooler according to the process steps e to k of hot ammonia cleaning of the primary cooler;

[0048] C. Hot oil cleaning process for horizontal tube primary cooler:

[0049] a. Clean the primary cooler with hot ammonia water according to the process steps a to i, empty the ammonia water in the cleaning temporary tank, pour the cleaning oil into the cleaning temporary tank, close the primary cooler inlet valve, introduce nitrogen into the primary cooler to eliminate the negative pressure, and then open the primary cooler vent pipe to keep the pressure at normal.

[0050] b. Use a temporary cleaning pump to deliver wash oil instead of hot ammonia water and spray wash oil into the upper and lower sections of the primary cooler. The wash oil flows by gravity to the temporary cleaning tank through the outlet of the upper and lower condensate return pipes to establish a cold circulation of wash oil.

[0051] c. Use steam to indirectly heat the wash oil using the heat exchange tube bundle of the primary cooler. Open the steam valve and introduce steam into the outlet of the circulating water or low temperature water outlet pipe of the primary cooler. Discharge the steam condensate from the outlet of the circulating water or low temperature water inlet pipe. Heat the wash oil to 80-85 degrees Celsius and test the density and viscosity of the wash oil to determine whether the hot wash oil cleaning of the primary cooler is complete.

[0052] d. Based on the changes in the density and viscosity of the wash oil, if the density and viscosity of the wash oil continue to rise, stop and send the wash oil to the mechanized ammonia clarification tank using a temporary cleaning pump. Replace the wash oil and circulate it until the density and viscosity of the wash oil no longer rise. The hot wash oil cleaning is then complete.

[0053] 2) Routine steam cleaning of the electrostatic precipitator, and determination of results:

[0054] A. Steam cleaning with a single electrostatic precipitator

[0055] a. The electrostatic precipitator is de-energized;

[0056] b. Close the inlet valve of the electrostatic precipitator, then close the outlet valve of the electrostatic precipitator. Introduce nitrogen into the electrostatic precipitator body. When the internal pressure is positive, open the vent pipe of the electrostatic precipitator. The electrostatic precipitator should be kept at normal pressure.

[0057] c. Open the cleaning steam valve of the electrostatic precipitator body. The condensate that has been cleaned off enters the blower underground tank through the gas water seal tank of the electrostatic precipitator.

[0058] d. After a large amount of steam comes out of the vent pipe of the electrostatic precipitator, check whether the condensate that has been cleaned is clear. If the condensate is clear and there are no tar or other substances, the electrostatic precipitator can be restored to work.

[0059] e. Close the cleaning steam valve of the electrostatic precipitator, open the nitrogen purging valve, and after a large amount of nitrogen gas comes out from the vent, close the vent pipe valve and close the nitrogen purging valve. Control the pressure of the electrostatic precipitator body to be less than 10 kPa during the nitrogen purging process. Open the inlet gas valve of the electrostatic precipitator to full opening and open the outlet gas valve of the electrostatic precipitator to full opening.

[0060] f. After the gas has been introduced into the electrostatic precipitator for 2 hours, the temperature of the insulation box of the electrostatic precipitator is controlled at 80-110℃. After the insulation of the electrostatic precipitator is tested and found to be qualified, power is supplied to the electrostatic precipitator.

[0061] B. Overall steam cleaning process for electrostatic precipitator system

[0062] a. Following the steam cleaning process steps af for a single electrostatic precipitator, clean all electrostatic precipitators one by one.

[0063] b. Power off all electrostatic precipitators;

[0064] c. Open the main gas pipeline of the electrostatic precipitator, and let all the gas flow directly into the gas blower through the main pipeline. Close the main inlet valve and the main outlet valve of the electrostatic precipitator.

[0065] d. Introduce nitrogen into the electrostatic precipitator system to confirm positive internal pressure. Open all vent pipes of the electrostatic precipitator and maintain normal pressure. Introduce steam into the inlet and outlet pipes and the body of the electrostatic precipitator. The condensate flows into the underground tank through the gas water seal tank of the electrostatic precipitator.

[0066] f. After a large amount of steam is emitted from the electrostatic precipitator vent pipe, check whether the condensate that has been cleaned is clear. If the condensate is clear and free of tar and other substances, the electrostatic precipitator can be restored to operation.

[0067] g. Close the steam valve of the electrostatic precipitator and open the nitrogen purging valve. After a large amount of nitrogen gas is released from the vent, close all the vent pipe valves of the electrostatic precipitator and close the nitrogen purging valve. Control the pressure of the electrostatic precipitator body to be less than 10 kPa during the nitrogen purging process. Open the main gas valve at the electrostatic precipitator inlet to full open and open the main gas valve at the electrostatic precipitator outlet to full open.

[0068] h. After the tar precipitator is circulated with coal gas for 2 hours, the temperature of the tar precipitator insulation box is controlled between 80 and 110°C, and then the tar precipitator is powered on.

[0069] 3) Routinely clean the condensate spray pipes in the upper and lower sections of the horizontal tube primary cooler;

[0070] Each time the primary cooler is cleaned, each spray pipe is thoroughly cleaned with circulating ammonia water. The pipes are disassembled and cleaned 1-2 times a year.

[0071] III. Quality Control of Condensate in the Upper and Lower Sections of the Horizontal Tube Primary Cooler

[0072] The light tar content in the upper and lower sections of the horizontal tube primary cooler is controlled between 10% and 30%. The light tar content in the lower section condensate is kept stable by dynamically adding light tar and continuously discharging it into the mechanized ammonia clarification tank.

[0073] IV. Emergency Cleaning Process for Non-Stop Negative Pressure Gas Systems

[0074] 1. Clean the gas pipeline from the outlet of the horizontal tube primary cooler to the electrostatic precipitator without stopping production:

[0075] 1) Move holes in the gas pipeline at the outlet of the horizontal tube primary cooler, one hole every 3 to 6 meters. Move a drain hole at the lowest point of the gas pipeline before the electrostatic precipitator. Connect the temporary drain pipeline of the electrostatic precipitator to the second temporary water seal tank. Connect the water seal outlet pipeline to the cleaning temporary tank.

[0076] 2) Open the ammonia water valve near the electrostatic precipitator inlet and spray circulating ammonia water into the negative pressure gas pipeline to flush the deposited material in the lower part of the gas pipeline into the drain hole. The ammonia water then enters the temporary cleaning tank through the temporary electrostatic precipitator drain pipe and the second temporary water seal tank. Check the full flow of the second temporary water seal tank to determine if there is any liquid accumulation. If there is liquid accumulation, stop cleaning. After the liquid accumulation is treated, cleaning can be repeated.

[0077] 3) Check if the condensate that has been cleaned is light yellow and there is no obvious tar, then the cleaning is considered complete;

[0078] 4) Change the ammonia spray position forward in sequence, spray circulating ammonia into the negative pressure gas, and repeat steps 2) and 3) to clean all the gas pipeline from the horizontal tube primary cooler to the electrostatic precipitator inlet.

[0079] 2. Clean the gas pipeline between the outlet main of the electrostatic precipitator and the inlet of the blower without stopping production:

[0080] 1) Make holes in advance on the gas pipeline from the outlet of the electrostatic precipitator to the inlet of the blower, making one hole every 4 to 6 meters, and connect it to the circulating ammonia water pipeline. Make a drain hole at the lowest point of the gas pipeline at the bottom of the blower inlet. Connect the temporary drain pipeline at the blower inlet to the third temporary water seal tank. Connect the water seal outlet pipeline to the cleaning temporary tank.

[0081] 2) Open the ammonia water valve near the blower inlet and spray circulating ammonia water into the negative pressure gas pipeline to flush the material deposited at the bottom of the gas pipeline into the drain hole. Discharge the ammonia water into the third temporary water seal tank through the temporary drain pipe at the blower inlet to isolate air from entering the cleaning temporary tank. Check the full flow of the water seal tanks of other blowers to determine whether there is liquid accumulation. If there is liquid accumulation, stop cleaning. After the liquid accumulation is dealt with, repeat the cleaning process.

[0082] 3) The condensate that has been swept away is pale yellow and has no obvious tar, which means the cleaning is complete;

[0083] 4) Change the ammonia spraying position forward in sequence, open the ammonia inlet valve to spray circulating ammonia into the negative pressure gas pipeline, repeat steps 2) and 3) to clean the entire gas pipeline from the electrostatic precipitator outlet main pipe to the blower inlet.

[0084] 5) Open the ammonia spray valve in front of the spare parts blower in sequence, and clean according to steps 2) and 3).

[0085] Compared with the prior art, the beneficial effects of the present invention are:

[0086] This invention comprises four aspects: First, by judging the process parameters monitored under various production conditions, timely adjustments to process parameters and operational control are made to avoid increasing the resistance of negative pressure gas equipment. Second, by predicting the resistance of negative pressure gas equipment in advance, a cleaning plan for negative pressure gas equipment is made in advance, and the equipment is dealt with in a timely manner even with slight blockages, avoiding the need for oil washing. Third, by controlling the quality of condensate in the upper and lower sections during daily production, a certain amount of light tar is added online to the upper and lower section condensate according to the principle of "like dissolves like," improving the cleaning quality of the upper and lower section condensate, ensuring the removal of impurities such as naphthalene in the gas, and avoiding the need for treatment after the negative pressure gas equipment is blocked. Fourth, by providing emergency response and handling for the negative pressure gas system without stopping production, for negative pressure gas facilities that cannot be shut down, an emergency cleaning strategy and two cleaning schemes are adopted to stabilize the resistance of the negative pressure gas system. This invention is based on daily process parameter monitoring and operation to minimize the blockage of negative pressure gas equipment. It predicts negative pressure gas resistance in advance based on seasonal production changes and proposes targeted cleaning plans to prevent resistance growth before it occurs, thus nipping the problem in the bud. It controls the quality of condensate in the upper and lower sections of the horizontal tube primary cooler, adding a certain amount of light tar to remove impurities such as naphthalene from the gas and extend the blockage period of the negative pressure gas facilities. For negative pressure gas facilities that cannot be shut down, different strategies are adopted, selecting appropriate online cleaning schemes to clean the negative pressure gas and maintain stable resistance. This is a process technology development and application that integrates daily process control, resistance prediction, advance cleaning operations, and online cleaning operations to control the resistance of negative pressure gas systems.

[0087] This invention conducts systematic technical analysis and research in both theory and production practice, avoiding the need for post-process cleaning of the primary cooler, electrostatic precipitator, and gas pipelines. It breaks through the methods and approaches for controlling and handling resistance in negative pressure gas systems involved in the field of gas purification, employing routine monitoring and operational control procedures for process parameters of negative pressure gas systems, routine resistance prediction and process cleaning procedures for negative pressure gas systems, and emergency response plans and procedures for negative pressure gas systems. When applied to negative pressure gas systems in gas purification, this system can stabilize the resistance of the negative pressure gas system over a long period, safeguarding production.

[0088] This invention integrates daily management and control, resistance prediction, advance cleaning operations, and online cleaning operations to maintain the long-term stable operation of the negative pressure gas system. Attached Figure Description

[0089] Figure 1 This is a process flow diagram of the present invention.

[0090] Figure 2 This is a schematic diagram of the structure and process principle of the present invention.

[0091] In the diagram: 1-Heating water outlet; 2-Heating water inlet; 3-Circulating water outlet; 4-Circulating water inlet; 5-Low-temperature water outlet; 6-Low-temperature water inlet; 7-Gas outlet; 8-Gas inlet; 9-Lower section water seal tank; 10-Upper section water seal tank; 11-Lower section condensate tank; 12-Upper section condensate tank; 13-Temporary cleaning tank; 14-Upper section condensate pump; 15-Lower section condensate pump; 16-Temporary cleaning pump; 17-First temporary water seal tank; 18-Ammonia circulating pump; 19-Ammonia water for coking; 20-Mechanized ammonia water clarification tank; 21-Upper section condensate discharge regulating valve; 22-Steam inlet; 23-Solvent addition; 24-Second temporary water seal tank; 25-Third temporary water seal tank; 26-Electrostatic tar precipitator; 27-Blower; 28-Blower. 29 - Gas pipe at the blower outlet; 30 - Gas main valve at the electrostatic precipitator inlet; 31-37 - Gas main valve at the electrostatic precipitator outlet; 38 - Ammonia water spray position; 39 - High-pressure ammonia water pump; 40 - Gas valve at the outlet of the horizontal tube primary cooler; 41 - Circulating water inlet valve; 42 - Circulating water outlet valve; 43 - Low-temperature water inlet valve; 44 - Upper condensate spray; 45 - Lower condensate spray; 46 - Upper ammonia water cleaning valve; 47 - Upper condensate return pipe; 48 - Lower ammonia water cleaning valve; 49 - Lower condensate return pipe; 50 - Gas inlet valve of the horizontal tube primary cooler; 51 - Temporary drain pipe for electrostatic precipitator; 52 - Temporary drain pipe at the blower inlet; 53 - Gas main circulation pipe; 54 - Horizontal tube primary cooler. Detailed Implementation

[0092] This invention discloses a method for controlling the resistance of a negative pressure gas system. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0093] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0094]

Example

[0095] like Figure 1 , Figure 2 As shown, a method for controlling the resistance of a negative pressure gas system specifically includes the following steps:

[0096] I. Process Parameter Control of Daily Negative Pressure Gas System

[0097] (I) Controlling the daily process parameters of the horizontal tube primary cooler, electrostatic precipitator, blower system, condensate system, circulating water system, and cryogenic water system:

[0098] The gas resistance P1-P2 value of the horizontal tube primary cooler 54 is controlled to be less than 1 kPa, and the gas outlet temperature T1 is controlled within 18-22℃.

[0099] The resistance values ​​P2-P3 of the electrostatic precipitator 26 are less than 1 kPa, and the normal voltage is maintained at 40,000 to 60,000 volts for tar collection.

[0100] Blower 27 has a suction power of 1.5 to 4.0 kPa, and the inlet and outlet gas pipelines and the main body of blower 27 are unobstructed.

[0101] The condensate flow rate in the upper section of each primary cooler shall not be less than 30 m³ / h. 3 / h, the lower section condensate flow rate is not less than 80m³ / h. 3 / h, the oil content in the lower section of the spray solution is between 10% and 30%, and the spray pipe should be cleaned once a year to ensure unobstructed and uniform spraying.

[0102] The circulating ammonia water pressure is 0.35–0.5 MPa, and the high-pressure ammonia water pressure is 2.3–2.5 MPa. The circulating water inlet 4 temperature is not lower than 26℃ in winter and 26–32℃ in summer. The low-temperature water inlet 6 temperature is not lower than 14℃ in winter and not higher than 16℃ in summer. 2–10 tons / hour of light tar are added to prevent naphthalene from condensing and precipitating in the gas at excessively low temperatures.

[0103] (II) Control of flow rate and pressure of circulating ammonia water and high-pressure ammonia water supply

[0104] The pressure of the ammonia water pump 19 for coking is maintained above 0.4 MPa to meet coking requirements and is adjusted as needed based on actual coking production requirements. The pressure of the circulating ammonia water is increased as much as possible to ensure the cooling and washing effect of the coal gas spray. The pressure of the high-pressure ammonia water pump 38 is maintained below 2.5 MPa to ensure no smoke is emitted during coal charging for coking. The pressure is adjusted as needed based on coking requirements, and the high-pressure ammonia water pressure is reduced as much as possible while ensuring no smoke is emitted.

[0105] (III) Control of blower system suction, inlet suction and temperature when gas volume is low

[0106] When the gas volume is low, while ensuring the coking suction, the gas suction P3 before the blower 27 system and the gas suction P1 before the primary cooler should be reduced as much as possible. The amount of gas passing through the primary cooler can be maintained by adjusting the number of horizontal tube primary coolers in operation through the gas circulation pipeline 53 to prevent uneven distribution of gas inside the primary cooler, which would cause the local temperature inside the primary cooler to be too low. The gas outlet temperature P2 can be maintained within a reasonable range by adjusting the temperature or flow rate of the low temperature water outlet 5 and the circulating water inlet 4.

[0107] (iv) Control of process parameters for horizontal tube primary cooler during winter hot water supply

[0108] During the winter heating water supply period, the temperature gradients inside the horizontal tube primary cooler 54 will change, and the heating water outlet 1 will take away a large amount of heat. It is necessary to strictly control the temperature of the circulating water inlet 4 to not be lower than 26℃ and the temperature of the low temperature water inlet 6 to not be lower than 14℃. The temperature of the circulating water inlet 4 and the low temperature water inlet 6 can be appropriately increased to maintain these temperatures.

[0109] II: Resistance Prediction and Cleaning Process of Daily Negative Pressure Gas Systems

[0110] (I) Prediction of resistance in negative pressure gas systems and determination of purging methods and frequencies

[0111] Based on the actual resistance changes P1-P2 of the horizontal tube primary cooler 54 during daily operation, when the resistance P1-P2 of the horizontal tube primary cooler 54 is relatively stable, a cleaning frequency for each primary cooler should be determined. Generally, the primary cooler needs to be cleaned every 3-6 days. The cleaning cycle of the primary cooler should be adjusted at any time according to the resistance changes to prevent the primary cooler from not being cleaned for a long time when the resistance is stable. The electrostatic precipitator 26 needs to be cleaned with steam every 3 months. All liquid discharge pipes of the gas pipeline need to be cleaned every 12 hours, and the gas outlet pipe 28 of the blower system and related liquid discharge pipes and the main body liquid discharge pipe need to be cleaned every 6 hours.

[0112] (II) Resistance purging process and result determination for negative pressure gas systems

[0113] 1. Cleaning process and result determination of hot ammonia water and hot washing oil in the upper and lower sections of the condensate system of the horizontal tube primary cooler.

[0114] (1) Hot ammonia water cleaning of the horizontal tube primary cooler 54 process:

[0115] 1) Slowly close the gas valve 39 at the outlet of the horizontal tube primary cooler to stop the operation of the primary cooler.

[0116] 2) Close the primary cooler circulating water inlet valve 40 and circulating water outlet valve 41, the low temperature water inlet valve 42 and low temperature water outlet valve 43, and drain the circulating water and low temperature water pipes and heat exchange tubes of the primary cooler.

[0117] 3) Stop the upper section condensate spraying 44 and the lower section condensate spraying 45 of the primary cooler.

[0118] 4) Switch the upper and lower section condensate outlets to the cleaning temporary tank 13.

[0119] 5) Slowly open the upper ammonia water cleaning valve 46. When the upper condensate enters the cleaning temporary tank 13 through the first temporary water seal tank 17 and the path is unobstructed, open the upper ammonia water cleaning valve 46 fully.

[0120] 6) Use the temporary cleaning pump 16 to send the cleaned condensate to the mechanized ammonia clarification tank 20.

[0121] 7) Based on the observation that the liquid at outlet 47 of the upper section of the condensate after cleaning is light yellow and oil-free, it can be determined that the cleaning of the upper section of the primary cooler is complete.

[0122] 8) Close the upper section ammonia water cleaning valve 46, slowly open the lower section ammonia water cleaning valve 48, and when the lower section condensate return pipe 49 enters the cleaning temporary tank through the first temporary water seal tank 17 and the route is unobstructed, open the lower section ammonia water cleaning valve 48 fully.

[0123] 9) Based on the observation that the liquid at the outlet of the lower section condensate return pipe 49 is light yellow and oil-free, it is determined that the cleaning of the lower section of the primary cooler is complete.

[0124] 10) The condensate in the upper and lower sections of the primary cooler returns to its initial state.

[0125] 11) Slowly supply circulating water to the upper section of the horizontal tube primary cooler 54 by adjusting the circulating water inlet valve 40 and supply low-temperature water to the lower section by adjusting the low-temperature water inlet valve 42. After the operation is normal, slowly open the gas outlet valve 39 of the horizontal tube primary cooler.

[0126] (2) Steam cleaning procedure for the horizontal tube primary cooler 54:

[0127] 1) Clean the horizontal tube primary cooler 54 according to the operation steps 1) to 9) of cleaning the primary cooler with hot ammonia water to prevent the coking of a small amount of tar inside the primary cooler. Slowly close the inlet valve 50 of the horizontal tube primary cooler, introduce a small amount of nitrogen into the primary cooler to eliminate the negative pressure of the primary cooler, and then open the vent pipe of the primary cooler to keep it at normal pressure.

[0128] 2) Open the cleaning valve of the steam inlet 22 at the bottom of the primary cooler to introduce direct steam into the horizontal tube primary cooler 54. The steam condensate enters the first temporary water seal tank 17 through the upper condensate return pipe 47 and the lower condensate return pipe 49, and finally enters the temporary cleaning tank 13. It can be sent to the mechanized ammonia water clarification tank 20 by the cleaning temporary pump 16.

[0129] 3) When a large amount of steam is emitted from the top of the horizontal tube primary cooler 54, observe the quality of the liquid inside the first temporary water seal tank 17. When it is transparent and there is no obvious tar, the steam cleaning of the primary cooler is completed, and the cleaning valve of the steam inlet 22 is closed.

[0130] 4) Perform hot ammonia cleaning and restore the primary cooler according to the operating steps 5) to 11) of cleaning the primary cooler with hot ammonia.

[0131] (3) Hot oil cleaning of the horizontal tube primary cooler 54 operating procedure:

[0132] 1) Clean the horizontal tube primary cooler 54 with hot ammonia water according to steps 1-9 of cleaning the primary cooler with hot ammonia water, empty the ammonia water in the cleaning temporary tank 13, pour washing oil into the cleaning temporary tank 13, slowly close the inlet valve 50 of the horizontal tube primary cooler, introduce a small amount of nitrogen into the primary cooler to eliminate the negative pressure of the primary cooler, and then open the primary cooler vent pipe to keep the pressure at normal.

[0133] 2) Use the temporary cleaning pump 16 to deliver wash oil instead of hot ammonia water and spray wash oil into the upper and lower sections of the primary cooler. The wash oil flows by gravity to the temporary cleaning tank 13 through the outlet of the upper section condensate return pipe 47 and the lower section condensate return pipe 49 to establish a wash oil cold circulation.

[0134] 3) Use steam to indirectly heat the wash oil using the heat exchange tube bundle of the primary cooler. Open the steam valve to introduce steam into the primary cooler circulating water outlet 3 or low temperature water outlet 5. Discharge the steam condensate from the vent pipe of the circulating water inlet 4 or low temperature water inlet 6. Heat the wash oil to 80-85℃ and test the density and viscosity of the wash oil to determine whether the hot wash oil cleaning of the primary cooler is complete.

[0135] 4) Based on the changes in the density and viscosity of the wash oil, if the density and viscosity of the wash oil continue to rise and the wash oil cannot circulate due to excessive viscosity, stop the process and send the wash oil to the mechanized ammonia clarification tank 20 using the temporary cleaning pump 16. Replace the wash oil and circulate it until the density and viscosity of the wash oil no longer rise. The hot wash oil cleaning is then complete.

[0136] 5) Follow steps 4) to 11) of cleaning the horizontal tube primary cooler with hot ammonia water to complete the ammonia water cleaning and restore the primary cooler.

[0137] 2. Determination of the process and results of steam cleaning electrostatic precipitator 26

[0138] (1) Single electrostatic precipitator with 26 steam cleaning

[0139] 1) The tar precipitator 26 is de-energized.

[0140] 2) Slowly close the main gas valve 29 at the inlet of the electrostatic precipitator, then close the main gas valve 30 at the outlet of the electrostatic precipitator. Introduce a small amount of nitrogen into the electrostatic precipitator body. When the internal pressure is positive, open the electrostatic precipitator vent pipe and maintain the electrostatic precipitator at normal pressure.

[0141] 3) Slowly open the cleaning steam valve of the electrostatic precipitator body, and the condensate that has been cleaned off enters the underground blast furnace through the electrostatic precipitator gas water seal tank.

[0142] 4) After a large amount of steam is emitted from the electrostatic precipitator vent pipe, check whether the condensate that has been swept down is clear. If the condensate is clear and free of tar or other substances, the electrostatic precipitator operation can be resumed.

[0143] 5) Close the cleaning steam valve of the electrostatic precipitator, open the nitrogen purging valve, and after a large amount of nitrogen gas is released from the vent, close the vent pipe valve and the nitrogen purging valve. Control the pressure of the electrostatic precipitator body to be less than 10 kPa during the nitrogen purging process. Slowly open the inlet gas valve 29 of the electrostatic precipitator to full opening, and then slowly open the outlet gas valve 30 of the electrostatic precipitator to full opening.

[0144] 6) After the tar precipitator 26 is purged with gas for 2 hours, the temperature of the tar precipitator insulation box is controlled between 80 and 110°C. After the tar precipitator insulation is tested and found to be qualified, power is supplied to the tar precipitator.

[0145] (2) Steam cleaning of the electrostatic precipitator system

[0146] 1) Following the steam cleaning steps 1) to 6) for a single electrostatic precipitator, all electrostatic precipitators 26 are cleaned one by one to reduce the overall steam cleaning time of the electrostatic precipitator system.

[0147] 2) All electrostatic precipitators 26 are de-energized.

[0148] 3) Open the gas circulation pipeline, and let all the gas flow directly into the gas blower 27 through the main pipeline. Close the main gas valve 29 at the inlet of the electrostatic precipitator and the main gas valve 30 at the outlet of the electrostatic precipitator.

[0149] 4) Introduce a small amount of nitrogen into the electrostatic precipitator system to confirm positive internal pressure. Open all the vent pipes of the electrostatic precipitator and maintain normal pressure. Introduce steam into the inlet and outlet pipes of the electrostatic precipitator and into the main body. The condensate flows into the underground tank through the electrostatic precipitator gas water seal tank.

[0150] 5) After a large amount of steam is emitted from the electrostatic precipitator vent pipe, check whether the condensate that has been swept down is clear. If the condensate is clear and free of tar or other substances, the electrostatic precipitator operation can be resumed.

[0151] 6) Close the cleaning steam valve of the electrostatic precipitator, open the nitrogen purging valve, and after a large amount of nitrogen gas is released from the vent, close all the venting pipe valves of the electrostatic precipitator and close the nitrogen purging valve. Control the pressure of the electrostatic precipitator body to be less than 10 kPa during the nitrogen purging process. Slowly open the main gas valve 29 at the inlet of the electrostatic precipitator to full opening, and then slowly open the main gas valve 30 at the outlet of the electrostatic precipitator to full opening.

[0152] 7) After the tar precipitator 26 is purged with gas for 2 hours, the temperature of the tar precipitator insulation box is controlled between 80 and 110°C. After the tar precipitator insulation is tested and found to be qualified, the tar precipitator 26 is powered on.

[0153] (3) Cleaning and control of condensate spray pipes in the upper and lower sections of the horizontal tube primary cooler

[0154] Over time, the spray holes of the upper and lower condensate spray pipes will become clogged. Each time the primary cooler is cleaned, each spray pipe should be thoroughly cleaned with circulating ammonia water. Depending on the degree of blockage, the pipes need to be disassembled and cleaned 1 to 2 times a year.

[0155] III. Quality control of condensate in the upper and lower sections of the horizontal tube primary cooler, specifically including:

[0156] The composition of the upper and lower condensates and the flow rate of added light tar are controlled. In the horizontal tube primary cooler 54, most of the tar condensed in the upper condensate remains in the upper condensate, which generally contains 10% to 30% light tar. The light tar content in the lower condensate does not meet the technical requirements, so light tar needs to be added to the lower condensate to control the oil content between 10% and 30%. The principle of "like dissolves like" is used to absorb substances such as naphthalene from the coal gas. The light tar content in the lower condensate is maintained by dynamically adding light tar and continuously discharging it into the mechanized ammonia clarification tank 20, thus maintaining a good absorption effect.

[0157] IV. Emergency Response Methods for Non-Stop Negative Pressure Gas Systems

[0158] (I) Emergency cleaning process for negative pressure gas systems

[0159] 1. Cleaning process between the outlet of the horizontal tube primary cooler and the electrostatic precipitator gas pipeline

[0160] (1) Make holes in advance on the gas outlet 7 of the horizontal tube primary cooler. Make one DN50 hole every 5 meters or so, and connect it to the pipelines of the circulating ammonia water spray positions 31, 32 and 36. Make one drain hole at the lowest point of the gas pipeline before electrostatic precipitation. Use the electrostatic precipitation temporary drain pipe 51 and connect it to the second temporary water seal tank 24. The water seal outlet is connected to the cleaning temporary tank 13.

[0161] (2) Slowly open the ammonia water valve near the electrostatic precipitator inlet and spray circulating ammonia water into the negative pressure gas pipeline to flush the tar and naphthalene deposited at the bottom of the gas outlet 7 pipeline into the drain hole. The ammonia water enters the temporary cleaning tank 13 through the temporary electrostatic precipitator drain pipe 51 and the second temporary water seal tank 24. Check the full flow of the second temporary water seal tank 24 to determine whether there is liquid accumulation. If there is liquid accumulation, stop cleaning. After the liquid accumulation is treated, cleaning can be repeated.

[0162] (3) Check whether the condensate that has been cleaned down is light yellow and has no obvious tar, then the cleaning is considered complete.

[0163] (4) Change the ammonia spray positions 31 and 36 in sequence, and spray circulating ammonia into the negative pressure gas. Repeat steps (2) to (3) to clean all the gas outlet pipes from the horizontal tube primary cooler to the electrostatic precipitator inlet.

[0164] 2. Cleaning process between the outlet main of the electrostatic precipitator and the inlet gas pipeline of the blower.

[0165] (1) Make holes in advance on the gas pipeline from the outlet of the electrostatic precipitator to the inlet of the blower. Make one hole every 5 meters or so, with a size of DN50, and connect it to the circulating ammonia water pipeline. Make one drain hole at the lowest point of the gas pipeline at the inlet of the blower. Use the temporary drain pipe 52 at the inlet of the blower and connect it to the third temporary water seal tank 25. Connect the water seal outlet to the cleaning temporary tank 13.

[0166] (2) Slowly open the ammonia water valve near the blower inlet and spray circulating ammonia water into the negative pressure gas pipeline to flush the tar and naphthalene deposited at the bottom of the gas pipeline into the drain hole. Use the blower inlet temporary drain pipe 52 to enter the cleaning temporary tank 13 through the third temporary water seal tank 25 with the ammonia water to isolate the air. Check the full flow of the water seal tanks of other blowers to determine whether there is liquid accumulation. If there is liquid accumulation, stop cleaning. After the liquid accumulation is dealt with, cleaning can be repeated.

[0167] (3) Check whether the condensate that has been cleaned down is light yellow and has no obvious tar, then the cleaning is considered complete.

[0168] (4) Change the ammonia spray position forward in sequence, open the valves of the inlet ammonia spray positions 34 and 35 to spray circulating ammonia into the negative pressure gas pipeline, repeat steps (2) to (3) to clean all the gas pipelines from the electrostatic outlet main pipe to the blower inlet.

[0169] (5) Open the ammonia spray valve in front of the spare blower in sequence and clean according to steps 2) to 2).

[0170] This invention conducts systematic technical analysis and research in both theory and production practice, avoiding the need for post-process cleaning of the horizontal tube primary cooler 54, electrostatic precipitator 26, and gas pipelines. It breaks through the methods and approaches for controlling and handling resistance in negative pressure gas systems involved in the field of gas purification, employing daily monitoring and operational control procedures for process parameters of negative pressure gas systems, daily resistance prediction and process cleaning procedures for negative pressure gas systems, and emergency response plans and procedures for negative pressure gas systems. When applied to negative pressure gas systems in gas purification, this system can stabilize the resistance of the negative pressure gas system over a long period, safeguarding production.

[0171] This invention integrates daily management and control, resistance prediction, advance cleaning operations, and online cleaning operations to maintain the long-term stable operation of the negative pressure gas system.

[0172] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention. Unless otherwise specified, the methods used in the above embodiments are conventional methods.

Claims

1. A method for controlling the resistance of a negative pressure gas system, characterized in that, Specifically, it includes: I. Process parameters for daily control of negative pressure gas systems (1) Controlling the process parameters of the horizontal tube primary cooler, electrostatic precipitator, blower system, condensate system, circulating water system, and cryogenic water system: The gas resistance of the horizontal tube primary cooler is less than 1 kPa, and the gas outlet temperature is 18~22℃; The resistance of the electrostatic precipitator is less than 1 kPa, and the voltage is maintained at 40,000 volts for tar collection. The gas pipeline drain pipes at the inlet and outlet of the blower system and the drain pipe of the blower body are unobstructed; The condensate flow rate in the upper section of each horizontal tube primary cooler in the condensate system shall not be less than 30 m³ / s. 3 / h, the lower section condensate flow rate is not less than 80m³ / h. 3 / h, the light tar content in the lower stage spray solution is 10%~30%; The inlet temperature of the circulating water system shall not be lower than 26℃ in winter and not higher than 32℃ in summer. The inlet temperature of the low-temperature water system shall not be lower than 14℃ in winter and not higher than 16℃ in summer. (2) Control the flow rate and pressure of circulating ammonia water and high-pressure ammonia water: The pressure of the circulating ammonia water sent to the coking plant is maintained above 0.4 MPa, and the pressure of the high-pressure ammonia water pump is below 2.5 MPa. (3) Controlling the suction of the blower system, the suction of the gas before the horizontal tube primary cooler, and the temperature when the gas volume is low. When the gas volume is low, reduce the gas suction in front of the blower system and the gas suction in front of the horizontal tube primary cooler while ensuring the coking suction. Maintain the gas outlet temperature within a reasonable range by adjusting the inlet temperature or flow rate of the low-temperature water and circulating water. (4) Control the process operating parameters of the horizontal tube primary cooler during the winter hot water supply period. The inlet temperature of circulating water shall be controlled to be no lower than 26℃, and the inlet temperature of low-temperature water shall be no lower than 14℃. II. Resistance Prediction and Cleaning of Daily Negative Pressure Gas Systems (1) Predict the resistance of the negative pressure gas system and determine the cleaning method and frequency: When the resistance of the horizontal tube primary cooler is stable, clean the horizontal tube primary cooler every 3 to 6 days; clean the electrostatic precipitator with steam every 3 months; clean each drain pipe of the gas pipeline every 12 hours; clean the outlet gas pipeline of the blower system and related drain pipes and the main body drain pipe every 6 hours. (2) Perform routine resistance purging of the negative pressure gas system and determine the results: 1) Routinely clean the condensate system of the upper and lower sections of the horizontal tube primary cooler with hot ammonia water, steam, and hot washing oil, and determine the results; A. Process of cleaning the horizontal tube primary cooler with hot ammonia water: a. Close the gas valve at the outlet of the horizontal tube primary cooler and stop the operation of the horizontal tube primary cooler; b. Close the inlet and outlet valves of the circulating water in the horizontal tube primary cooler, close the inlet and outlet valves of the low-temperature water, and drain the circulating water and low-temperature water pipes and heat exchange tubes of the horizontal tube primary cooler. c. Stop the spraying of condensate in the upper and lower sections of the horizontal tube primary cooler; d. Switch the upper and lower section condensate outlets to the temporary cleaning tank; e. Open the upper section ammonia water cleaning valve. When the upper section condensate flows smoothly from the first temporary water seal tank into the cleaning temporary tank, open the upper section ammonia water cleaning valve fully. f. Use a temporary cleaning pump to send the cleaned-up condensate to a mechanized ammonia clarification tank; g. If the liquid at the outlet of the upper section of the condensate after cleaning is light yellow and oil-free, then the upper section of the horizontal tube primary cooler is cleaned. h. Close the upper section ammonia water cleaning valve and open the lower section ammonia water cleaning valve. When the lower section condensate return pipeline flows smoothly into the cleaning temporary tank through the first temporary water seal tank, open the lower section ammonia water cleaning valve fully. i. If the liquid at the outlet of the lower section of the condensate after cleaning is light yellow and oil-free, then the cleaning of the lower section of the horizontal tube primary cooler is complete. j. The condensate in the upper and lower sections of the horizontal tube primary cooler returns to its initial state; k. The upper section of the horizontal tube primary cooler is supplied with circulating water by adjusting the circulating water inlet valve, and the lower section of the horizontal tube primary cooler is supplied with low-temperature water by adjusting the low-temperature water inlet valve. After normal operation, the gas outlet valve of the horizontal tube primary cooler is opened. B. Steam cleaning process for the horizontal tube primary cooler: a. Clean the horizontal tube primary cooler according to the process steps a~i of cleaning the horizontal tube primary cooler with hot ammonia water, close the inlet valve of the horizontal tube primary cooler, introduce nitrogen into the horizontal tube primary cooler to eliminate the negative pressure of the horizontal tube primary cooler, and then open the vent pipe of the horizontal tube primary cooler to keep it at normal pressure. b. Open the steam purging valve at the bottom of the horizontal tube primary cooler to introduce direct steam into the horizontal tube primary cooler. The steam condensate enters the first temporary water seal tank through the upper condensate return pipe and the lower condensate return pipe, and finally enters the temporary purging tank. It is then sent to the mechanized ammonia water clarification tank by the temporary purging pump. c. When a large amount of steam is emitted from the top of the horizontal tube primary cooler, observe the quality of the liquid inside the first temporary water seal tank. When it is transparent and there is no obvious tar, the steam cleaning of the horizontal tube primary cooler is complete, and the steam cleaning valve is closed. d. Perform hot ammonia cleaning and restore the horizontal tube primary cooler according to the process steps j~k of cleaning the horizontal tube primary cooler with hot ammonia water. C. Hot oil cleaning process for horizontal tube primary cooler: a. Clean the horizontal tube primary cooler with hot ammonia water according to the process steps a~i. Empty the ammonia water in the cleaning temporary tank, pour the cleaning oil into the cleaning temporary tank, close the inlet valve of the horizontal tube primary cooler, introduce nitrogen into the horizontal tube primary cooler to eliminate the negative pressure, and then open the vent pipe of the horizontal tube primary cooler to keep it at normal pressure. b. Use a temporary cleaning pump to deliver wash oil instead of hot ammonia water and spray wash oil into the upper and lower sections of the horizontal tube primary cooler. The wash oil flows by gravity to the temporary cleaning tank through the outlet of the upper and lower condensate return pipes to establish a wash oil cold circulation. c. Use steam to indirectly heat the wash oil in the heat exchange tube bundle of the horizontal tube primary cooler. Open the steam valve and introduce steam into the outlet of the circulating water or low temperature water outlet pipe of the horizontal tube primary cooler. Discharge the steam condensate from the vent pipe of the circulating water or low temperature water inlet pipe. Heat the wash oil to 80~85℃ and test the density and viscosity of the wash oil to determine whether the hot wash oil cleaning of the horizontal tube primary cooler is complete. d. Based on the changes in the density and viscosity of the wash oil, if the density and viscosity of the wash oil continue to rise, stop and send the wash oil to the mechanized ammonia clarification tank using a temporary cleaning pump. Replace the wash oil and circulate it until the density and viscosity of the wash oil no longer rise. The hot wash oil cleaning is then complete. 2) Routine steam cleaning of the electrostatic precipitator, and determination of results: A. Steam cleaning with a single electrostatic precipitator a. The electrostatic precipitator is de-energized; b. Close the inlet valve of the electrostatic precipitator, then close the outlet valve of the electrostatic precipitator, and introduce nitrogen into the electrostatic precipitator body. When the internal pressure is positive, open the vent pipe of the electrostatic precipitator and keep the electrostatic precipitator at normal pressure. c. Open the cleaning steam valve of the electrostatic precipitator body. The condensate that has been cleaned off enters the blower underground tank through the gas water seal tank of the electrostatic precipitator. d. After a large amount of steam comes out of the vent pipe of the electrostatic precipitator, check whether the condensate that has been cleaned is clear. If the condensate is clear and there is no tar, then restore the operation of the electrostatic precipitator. e. Close the steam valve of the electrostatic precipitator, open the nitrogen purging valve, and after a large amount of nitrogen gas is released from the vent, close the vent pipe valve and the nitrogen purging valve. Control the pressure of the electrostatic precipitator body to be less than 10 kPa during the nitrogen purging process. Open the inlet gas valve of the electrostatic precipitator to full opening and open the outlet gas valve of the electrostatic precipitator to full opening. f. After the gas has been introduced into the electrostatic precipitator for 2 hours, the temperature of the insulation box of the electrostatic precipitator is controlled at 80~110℃. After the insulation of the electrostatic precipitator is tested and found to be qualified, power is supplied to the electrostatic precipitator. B. Overall steam cleaning process for electrostatic precipitator system a. Following the steam cleaning process steps af for a single electrostatic precipitator, clean all electrostatic precipitators one by one. b. Power off all electrostatic precipitators; c. Open the main gas pipeline of the electrostatic precipitator, and let all the gas flow directly into the gas blower through the main pipeline. Close the main inlet valve and the main outlet valve of the electrostatic precipitator. d. When nitrogen is introduced into the electrostatic precipitator system to confirm the internal positive pressure, open the vent pipes of all electrostatic precipitators, keep the pressure at normal and unobstructed, and introduce steam into the inlet and outlet pipes and body of the electrostatic precipitator. The condensate flows into the underground tank through the gas water seal tank of the electrostatic precipitator. f. After a large amount of steam comes out of the vent pipe of the electrostatic precipitator, check whether the condensate that has been cleaned is clear. If the condensate is clear and there is no tar, then restore the operation of the electrostatic precipitator. g. Close the steam valve of the electrostatic precipitator, open the nitrogen purging valve, and after a large amount of nitrogen gas is released from the vent, close all the vent pipe valves of the electrostatic precipitator, close the nitrogen purging valve, control the pressure of the electrostatic precipitator body to be less than 10 kPa during the nitrogen purging process, open the main gas valve at the inlet of the electrostatic precipitator to full open, and open the main gas valve at the outlet of the electrostatic precipitator to full open. h. After the gas has been introduced into the electrostatic precipitator for 2 hours, the temperature of the insulation box of the electrostatic precipitator is controlled between 80 and 110°C, and then the electrostatic precipitator is powered on. 3) Routinely clean the condensate spray pipes in the upper and lower sections of the horizontal tube primary cooler; Each time the horizontal tube primary cooler is cleaned, each spray pipe is cleaned one by one with circulating ammonia water. It is disassembled and cleaned 1-2 times a year. III. Quality Control of Condensate in the Upper and Lower Sections of the Horizontal Tube Primary Cooler The light tar content in the upper and lower sections of the horizontal tube primary cooler is controlled at 10-30%. The light tar content in the lower section condensate is kept stable by dynamically adding light tar and continuously discharging it into the mechanized ammonia clarification tank. IV. Emergency Cleaning Process for Non-Stop Negative Pressure Gas Systems (1) Clean the gas pipeline between the outlet of the horizontal tube primary cooler and the electrostatic precipitator without stopping production: 1) Open a hole in the gas pipeline at the outlet of the horizontal tube primary cooler, and open one hole every 3 to 6 meters. Open a drain hole at the lowest point of the gas pipeline before the electrostatic precipitator. Connect the temporary drain pipe of the electrostatic precipitator to the second temporary water seal tank, and connect the water seal outlet pipe to the cleaning temporary tank. 2) Open the ammonia water valve near the inlet of the electrostatic precipitator and spray circulating ammonia water into the negative pressure gas pipeline to flush the deposited material in the lower part of the gas pipeline into the drain hole. The ammonia water then flows through the temporary drain pipe of the electrostatic precipitator and into the temporary cleaning tank through the second temporary water seal tank. Check the full flow of the second temporary water seal tank to determine if there is any liquid accumulation. If there is liquid accumulation, stop cleaning. After the liquid accumulation is treated, cleaning can be repeated. 3) Check if the condensate that has been cleaned is light yellow and there is no obvious tar, then the cleaning is considered complete; 4) Change the ammonia spray position forward in sequence, spray circulating ammonia into the negative pressure gas pipeline, and repeat steps 2) and 3) to clean the entire gas pipeline from the horizontal tube primary cooler to the inlet of the electrostatic precipitator. (2) Clean the gas pipeline between the outlet main of the electrostatic precipitator and the inlet of the blower without stopping production: 1) Make holes in advance on the gas pipeline from the outlet main pipe of the electrostatic precipitator to the inlet gas pipeline of the blower, one hole every 4 to 6 meters, and connect it to the circulating ammonia water pipeline. Make a drain hole at the lowest point of the gas pipeline at the bottom of the blower inlet. Connect the temporary drain pipeline at the blower inlet to the third temporary water seal tank, and connect the water seal outlet pipeline to the cleaning temporary tank. 2) Open the ammonia water valve near the blower inlet and spray circulating ammonia water into the negative pressure gas pipeline to flush the material deposited at the bottom of the gas pipeline into the drain hole. Discharge the ammonia water into the third temporary water seal tank through the temporary drain pipe at the blower inlet to isolate air from entering the cleaning temporary tank. Check the full flow of the water seal tanks of other blowers to determine whether there is liquid accumulation. If there is liquid accumulation, stop cleaning. After the liquid accumulation is dealt with, repeat the cleaning process. 3) The condensate that has been swept away is pale yellow and has no obvious tar, which means the cleaning is complete; 4) Change the ammonia spraying position forward in sequence, open the ammonia inlet valve to spray circulating ammonia into the negative pressure gas pipeline, and repeat steps 2) and 3) to clean the entire gas pipeline from the outlet main of the electrostatic precipitator to the inlet of the blower. 5) Open the ammonia spray valve in front of the blower inlet valve in sequence, and clean according to steps 2) and 3).

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