A tar distillation tail gas incineration process and device

Abstract

The present invention relates to a tar distillation tail gas incineration process and device, including a Class C product storage tank, a Class C product absorption system, a Class A and B product absorption system, a temperature recording and regulating instrument, a proportional regulating flow recording and regulating instrument, a flow recording and regulating instrument, a pressure recording and regulating instrument, a pressure recording and regulating instrument A, a breathing valve, a pressure regulating valve, a Class A and B product storage tank, an oxygen content analysis instrument, an air blower, a tail gas incinerator, a flow regulating valve, a solenoid valve and a nitrogen self-supporting regulating valve. Its beneficial effects are: different treatment methods are adopted according to the tail gas properties, which not only utilizes the combustible gas in the tail gas, but also reduces the number of tail gas treatments, reduces the risk hazards, and reduces the operating cost.

Description

Technical Field

[0001] The invention relates to the technical field of tail gas treatment in coal coking industry, and in particular to a tar distillation tail gas incineration process and device. Background Art

[0002] In the coal coking industry, the tail gas from the tar distillation unit is divided into four categories: the first category is the tail gas from Class C products, such as the tail gas from the raw material tar tank, phenol oil tank, oil wash tank, anthracene oil tank, asphalt tank, etc.; the second category is the tail gas from Class B products, such as the tail gas from the industrial naphthalene tank, high-temperature modified asphalt tank, kerosene tank, etc.; the third category is the tail gas from Class A products, such as the tail gas from the light oil tank, etc.; the fourth category is the tail gas from the thermal polycondensation reaction, such as the tail gas after the modified asphalt reactor is cooled, which is a non-condensable combustible gas. After on-site testing, the calorific value of this tail gas is higher than that of coal gas.

[0003] Absorption plus incineration is the latest tail gas treatment solution advocated by the country. At present, the only domestic process for treating tail gas from tar distillation units using absorption plus incineration is to combine all the above four types of tail gas together, wash them with washing oil, absorb them, and then send them to the incinerator for incineration, and all storage tanks are not nitrogen sealed; the tail gas itself contains a lot of air. Although this incineration process can reduce a lot of combustion-supporting air and save fuel, it also has certain risks. The absorption method before incineration cannot completely remove the combustible substances in the tail gas, especially the fourth type is non-condensable combustible gas. The mixture of air and combustible gas has the risk of flashback. Practice has proved that flashback accidents have indeed occurred.

[0004] The existing tail gas treatment processes of absorption and incineration basically adopt the method of nitrogen sealing in the storage tank, and the tail gas is sent to the incinerator for incineration after washing, and no separate treatment is carried out according to the properties of the tail gas. The tail gas volume is particularly large, which not only wastes a lot of nitrogen resources, but also consumes a lot of fuel gas. Since the storage tank is equipped with a breathing valve, the breathing valve is equivalent to a safety valve for the storage tank and is indispensable. In practice, in many extreme cases, due to the untimely replenishment of nitrogen, a large amount of air is often added, and the risk of flashback still exists. Summary of the invention

[0005] In order to overcome the defects of the prior art, the technical problem solved by the present invention is to provide a tar distillation tail gas incineration process and device, which adopts different treatment methods according to the properties of the tail gas, thereby utilizing the combustible gas in the tail gas and reducing the amount of tail gas treatment, thereby reducing risks and hidden dangers and reducing operating costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A tar distillation tail gas incineration device, comprising a Class C product storage tank, a Class C product absorption system, a Class A and B product absorption system, a temperature recording and regulating instrument, a proportional flow recording and regulating instrument, a flow recording and regulating instrument, a pressure recording and regulating instrument, a pressure recording and regulating instrument A, a breathing valve, a pressure regulating valve, a Class A and B product storage tank, an oxygen content analysis instrument, an air blower, a tail gas incinerator, a flow regulating valve, a solenoid valve, a pressure regulating valve A, a nitrogen self-supporting regulating valve and a nitrogen self-supporting regulating valve A, characterized in that the Class C product storage tank is connected to the Class C product adsorption system through a pressure regulating valve, the Class C product adsorption system is connected to an air pipeline provided with an air blower and a proportional flow recording and regulating instrument and connected to the tail gas incinerator, and is located between the air blower and the proportional flow recording and regulating instrument; the pressure recording and regulating instrument is arranged on the pipeline in front of the pressure regulating valve and is interlocked with the pressure regulating valve for control;

[0008] The Class A and B product storage tank is connected to the pressure regulating valve A and the solenoid valve, and then connected to the Class A and B product adsorption system, and the Class A and B product adsorption system is connected to the tail gas incinerator; the pressure recording and regulating instrument A is arranged on the pipeline in front of the pressure regulating valve A and is interlocked with the pressure regulating valve A; the oxygen content analysis instrument is arranged on the pipeline between the pressure regulating valve A and the solenoid valve and is interlocked with the solenoid valve; the nitrogen self-supporting regulating valve and the nitrogen self-supporting regulating valve A are connected in parallel and then connected to the Class A and B product storage tank;

[0009] The tail gas of the thermal polycondensation reaction is connected to a gas pipeline provided with a flow regulating valve and a flow recording and regulating instrument and connected to the tail gas incinerator, and is located between the flow regulating valve and the flow recording and regulating instrument; the temperature recording and regulating instrument is arranged on the tail gas incinerator;

[0010] The temperature recording and regulating instrument is interlocked with the flow regulating valve and the flow recording and regulating instrument; the proportional regulating flow recording and regulating instrument is interlocked with the air fan; the flow recording and regulating instrument is connected with the proportional regulating flow recording and regulating instrument by a data line;

[0011] The Class C product storage tank and the Class A and B product storage tanks are both provided with breathing valves.

[0012] A tar distillation tail gas incineration process comprises the following steps:

[0013] 1) Treatment of Class C product tail gas: Since the operating temperature of Class C product liquid does not reach the flash point, the released tail gas does not belong to explosive gas. This type of storage tank adopts natural breathing instead of nitrogen sealing. The operating pressure control range of Class C product storage tank is -0.2~0.4kPa. When the pressure recording and regulating instrument shows less than -0.2kPa, air is inhaled through the breathing valve. When it is greater than 0.4kPa, the excess Class C product tail gas is opened and discharged through the pressure regulating valve and sent to the Class C product adsorption system for treatment. The washed Class C product tail gas is basically composed of air and a small amount of Class C gas, which is sent to the tail gas incinerator for incineration as air. Since this part of the tail gas accounts for more than 80% of the tar distillation tail gas, this greatly reduces the total amount of tail gas entering the incinerator that needs to be incinerated;

[0014] 2) Treatment of tail gas of Class A and B products: The operating pressure control range of Class A and B product storage tanks is -0.2~0.4kPa. When the pressure recording and regulating instrument A displays <0kPa, open the nitrogen self-supporting regulating valve A to replenish nitrogen. When it is <-0.1kPa, open the nitrogen self-supporting regulating valve A to replenish nitrogen. When it is <-0.2kPa, inhale air through the breathing valve.

[0015] When the pressure recording and regulating instrument A displays >0.4kPa, it is opened and the excess Class A and B product tail gas is discharged through the pressure regulating valve A, and when the oxygen content analysis instrument displays <0.5%, the solenoid valve is opened to send the discharged Class A and B product tail gas to the Class A and B product adsorption system for treatment. The cleaned Class A and B product tail gas is sent to the tail gas incinerator for incineration as the tail gas to be purified, and no backfire occurs;

[0016] 3) Treatment of tail gas from thermal polycondensation reaction: non-condensable combustible gas, i.e. tail gas after the modified asphalt is cooled, is merged into the fuel gas, i.e. the gas pipeline, and directly sent to the incinerator for incineration as fuel gas, which can save a lot of gas;

[0017] 4) The tail gas incinerator burns or decomposes the harmful components in the tail gas through the high temperature generated by combustion in the furnace. During the operation of the tail gas incinerator, three material gases are involved: coal gas, combustion-supporting air and tail gas to be purified. The thermal polycondensation reaction tail gas, i.e., non-condensable combustible gas, is burned first. The furnace temperature is controlled at 900-1000°C to ensure the combustion and decomposition of harmful substances in the purified tail gas. When the temperature recording and regulating instrument shows <900°C, open the flow regulating valve to introduce coal gas and gradually increase the amount of coal gas until the temperature recording and regulating instrument shows ≦1000°C; while introducing the thermal polycondensation reaction tail gas and coal gas, start the air fan, and give priority to the introduced Class C product tail gas, which is basically air. The ratio of the flow of the thermal polycondensation reaction tail gas + coal gas to the flow of the Class C product tail gas + air introduced into the tail gas incinerator is 1:5 through the proportional adjustment flow recording and regulating instrument and the flow recording and regulating instrument control.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) Different treatment methods are adopted according to the properties of tail gas, which not only utilizes the combustible gas in the tail gas, but also reduces the amount of tail gas treatment, reduces risks and hidden dangers, and reduces operating costs;

[0020] 2) After the Class C product tail gas is treated by absorption method, it is basically air plus a small amount of Class C gas, which can be completely incorporated into the combustion air as air. Since this part of tail gas accounts for more than 80% of the total tail gas of the tar distillation unit, the amount of tail gas can be reduced;

[0021] 3) The tail gas of Class A and B products is explosive gas. For safety reasons, all of them are nitrogen-sealed. After the combined tail gas is treated by absorption method, it is basically nitrogen and a small amount of Class A, B and C gases. It enters the incinerator as tail gas that needs to be purified. Since there is no mixing of air, there is no risk of flashback.

[0022] 4) The tail gas from the thermal polycondensation reaction, which is a non-condensable combustible gas, is incorporated into the gas pipeline and sent to the tail gas incinerator as fuel gas, which can save a lot of coal gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the process principle of the present invention.

[0024] In the figure: 1-Class C product storage tank 2-Class C product absorption system 3-Class A and B product absorption system 4-Temperature recording and regulating instrument 5-Proportional regulation flow recording and regulating instrument 6-Flow recording and regulating instrument 7-Pressure recording and regulating instrument 8-Pressure recording and regulating instrument A 9-Breathing valve 10-Pressure regulating valve 11-Class A and B product storage tank 12-Oxygen content analysis instrument 13-Air fan 14-Tail gas incinerator 15-Flow regulating valve 16-Solenoid valve 17-Pressure regulating valve A 18-Nitrogen self-supporting regulating valve 19-Nitrogen self-supporting regulating valve A 20-Thermal polycondensation reaction tail gas DETAILED DESCRIPTION

[0025] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0026] See Figure 1As shown, the present invention relates to a tar distillation tail gas incineration device, including a Class C product storage tank 1, a Class C product absorption system 2, a Class A and B product absorption system 3, a temperature recording and regulating instrument 4, a proportional regulation flow recording and regulating instrument 5, a flow recording and regulating instrument 6, a pressure recording and regulating instrument 7, a pressure recording and regulating instrument A8, a breathing valve 9, a pressure regulating valve 10, a Class A and B product storage tank 11, an oxygen content analysis instrument 12, an air blower 13, a tail gas incinerator 14, a flow regulating valve 15, a solenoid valve 16, and a pressure regulating valve A17, nitrogen self-supporting regulating valve 18 and nitrogen self-supporting regulating valve A19, the Class C product storage tank 1 is connected to the Class C product adsorption system 2 through the pressure regulating valve 10, the Class C product adsorption system 2 is connected to the air pipeline provided with the air fan 13 and the proportional regulating flow recording regulating instrument 5 and connected to the tail gas incinerator 14, and the position is located between the air fan 13 and the proportional regulating flow recording regulating instrument 5; the pressure recording regulating instrument 7 is arranged on the pipeline in front of the pressure regulating valve 10 and is interlocked with the pressure regulating valve 10;

[0027] The Class A and B product storage tank 11 is connected to the pressure regulating valve A17 and the solenoid valve 16, and then connected to the Class A and B product adsorption system 3, and the Class A and B product adsorption system 3 is connected to the tail gas incinerator 14; the pressure recording and regulating instrument A8 is arranged on the pipeline in front of the pressure regulating valve A17 and is interlocked with the pressure regulating valve A17; the oxygen content analysis instrument 12 is arranged on the pipeline between the pressure regulating valve A17 and the solenoid valve 16 and is interlocked with the solenoid valve 16; the nitrogen self-supporting regulating valve 18 and the nitrogen self-supporting regulating valve A19 are connected in parallel and then connected to the Class A and B product storage tank 11;

[0028] The thermal polycondensation reaction tail gas 20 is connected to a gas pipeline provided with a flow regulating valve 15 and a flow recording and regulating instrument 6 and connected to the tail gas incinerator 14, and is located between the flow regulating valve 15 and the flow recording and regulating instrument 6; the temperature recording and regulating instrument 4 is arranged on the tail gas incinerator 14;

[0029] The temperature recording and regulating instrument 4 is interlocked with the flow regulating valve 15 and the flow recording and regulating instrument 6; the proportional regulating flow recording and regulating instrument 5 is interlocked with the air blower 13; the flow recording and regulating instrument 6 is connected with the proportional regulating flow recording and regulating instrument 5 by a data line, and can transmit and compare shared data;

[0030] The Class C product storage tank 1 and the Class A and B product storage tank 11 are both provided with a breathing valve 9 .

[0031] A tar distillation tail gas incineration process comprises the following steps:

[0032] 1) Treatment of Class C product tail gas: Since the operating temperature of Class C product liquid does not reach the flash point, the released tail gas does not belong to explosive gas. This type of storage tank adopts natural breathing instead of nitrogen sealing. The operating pressure control range of Class C product storage tank 1 is -0.2~0.4kPa. When the pressure recording and regulating instrument 7 shows <-0.2kPa, air is inhaled through the breathing valve 9. When it is >0.4kPa, it is opened and the excess Class C product tail gas is discharged through the pressure regulating valve 10 and sent to the Class C product adsorption system 2 for treatment. The washed Class C product tail gas is basically composed of air and a small amount of Class C gas, which is sent to the tail gas incinerator 14 for incineration as air. Since this part of tail gas accounts for more than 80% of the tar distillation tail gas, this greatly reduces the total amount of tail gas entering the incinerator that needs to be incinerated;

[0033] 2) Treatment of tail gas of Class A and B products: The operating pressure control range of Class A and B product storage tank 11 is -0.2~0.4kPa. When the pressure recording and regulating instrument A8 displays <0kPa, the nitrogen self-supporting regulating valve A19 is opened to replenish nitrogen. When it is <-0.1kPa, the nitrogen self-supporting regulating valve 18 is opened to replenish nitrogen. When it is <-0.2kPa, air is inhaled through the breathing valve 9.

[0034] When the pressure recording and regulating instrument A8 displays >0.4kPa, it is opened and the excess Class A and B product tail gas is discharged through the pressure regulating valve A17, and when the oxygen content analyzing instrument 12 displays <0.5%, the solenoid valve 16 is opened to send the discharged Class A and B product tail gas to the Class A and B product adsorption system 3 for treatment, and the washed Class A and B product tail gas is sent to the tail gas incinerator 14 for incineration as the tail gas to be purified, without flashback;

[0035] The liquid operating temperature of the tail gas of Class A and B products generally exceeds the flash point, and the released tail gas is an explosive gas. This type of storage tank is nitrogen-sealed. In order to prevent low pressure under extreme conditions (sudden change in ambient temperature, instant condensation of a large amount of steam generated by the steam purge pipeline, and failure of the self-supporting regulating valve for replenishing nitrogen), nitrogen cannot be replenished in time due to the limitation of the maximum flow of the self-supporting regulating valve. In order to reduce the probability of inhaling air through the breathing valve, two nitrogen replenishment pipelines are used, each of which is equipped with a nitrogen vertical regulating valve to ensure timely replenishment of nitrogen and that the tail gas will not be mixed with air. To prevent any accidents, when the pressure is high, the pipeline where the tail gas is sent out through the regulating valve is also equipped with an oxygen analyzer. When the oxygen content of the tail gas exceeds the standard, the solenoid valve is used to close the tail gas pipeline, and the tail gas is continued to be sent out normally after the nitrogen is fully replaced. After being washed with washing oil, the tail gas composition is basically nitrogen and a very small amount of Class A, B and C gases, and enters the incinerator as tail gas that needs to be purified without flashback.

[0036] 3) Treatment of thermal polycondensation reaction tail gas 20: The main component is non-condensable combustible gas, that is, tail gas after the modified asphalt is cooled, which is merged into the fuel gas, that is, the coal gas pipeline, and directly sent to the incinerator 14 for incineration as fuel gas, which can save a lot of coal gas;

[0037] 4) The tail gas incinerator 14 burns or decomposes harmful components in the tail gas through the high temperature generated by combustion in the furnace. During the operation of the tail gas incinerator 14, three material gases are involved: coal gas, combustion air and tail gas to be purified. The thermal polycondensation reaction tail gas 20, i.e., non-condensable combustible gas, is burned first. The furnace temperature is controlled at 900-1000°C to ensure the combustion and decomposition of harmful substances in the purified tail gas. When the temperature recording and regulating instrument 4 shows <900°C, the flow regulating valve 6 is opened. Coal gas is introduced and the amount of coal gas is gradually increased until the temperature recording and regulating instrument 4 displays ≦1000°C, and then the coal gas is stopped; while introducing the thermal polycondensation reaction tail gas 20 and coal gas, the air blower 13 is started, and the incorporated Class C product tail gas, which is basically air, is introduced first, and the ratio of the flow of the thermal polycondensation reaction tail gas 20 + coal gas introduced into the tail gas incinerator 14 to the flow of the Class C product tail gas + air is 1:5 through the proportional adjustment of the flow recording and regulating instrument 5 and the flow recording and regulating instrument 6.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A tar distillation tail gas incineration device, comprising a Class C product storage tank, a Class C product absorption system, a Class A and B product absorption system, a temperature recording and regulating instrument, a proportional regulating flow recording and regulating instrument, a flow recording and regulating instrument, a pressure recording and regulating instrument, a pressure recording and regulating instrument A, a breathing valve, a pressure regulating valve, a Class A and B product storage tank, an oxygen content analysis instrument, an air blower, a tail gas incinerator, a flow regulating valve, a solenoid valve, a pressure regulating valve A, a nitrogen self-supporting regulating valve and a nitrogen self-supporting regulating valve A, characterized in that: The Class C product storage tank is connected to the Class C product adsorption system through a pressure regulating valve, and the Class C product adsorption system is connected to an air pipeline provided with an air fan and a proportional flow recording and regulating instrument and connected to the tail gas incinerator, and is located between the air fan and the proportional flow recording and regulating instrument; the pressure recording and regulating instrument is arranged on the pipeline in front of the pressure regulating valve and is interlocked with the pressure regulating valve for control; The Class A and B product storage tank is connected to the pressure regulating valve A and the solenoid valve, and then connected to the Class A and B product adsorption system, and the Class A and B product adsorption system is connected to the tail gas incinerator; the pressure recording and regulating instrument A is arranged on the pipeline in front of the pressure regulating valve A and is interlocked with the pressure regulating valve A; the oxygen content analysis instrument is arranged on the pipeline between the pressure regulating valve A and the solenoid valve and is interlocked with the solenoid valve; the nitrogen self-supporting regulating valve and the nitrogen self-supporting regulating valve A are connected in parallel and then connected to the Class A and B product storage tank; The tail gas of the thermal polycondensation reaction is connected to a gas pipeline provided with a flow regulating valve and a flow recording and regulating instrument and connected to the tail gas incinerator, and is located between the flow regulating valve and the flow recording and regulating instrument; the temperature recording and regulating instrument is arranged on the tail gas incinerator; The temperature recording and regulating instrument is interlocked with the flow regulating valve and the flow recording and regulating instrument; The proportional regulation flow recording and regulating instrument is interlocked with the air blower; the flow recording and regulating instrument is connected to the proportional regulation flow recording and regulating instrument by a data line; The Class C product storage tank and the Class A and B product storage tanks are both provided with breathing valves.

2. A tar distillation tail gas incineration process using a tar distillation tail gas incineration device according to claim 1, characterized in that: The steps include: 1) Treatment of Class C product tail gas: The operating pressure control range of the Class C product storage tank is -0.2~0.4kPa. When the pressure recording and regulating instrument shows < -0.2kPa, air is inhaled through the breathing valve. When it is > 0.4kPa, the pressure regulating valve is opened and the excess Class C product tail gas is discharged through the pressure regulating valve and sent to the Class C product adsorption system for treatment. The cleaned Class C product tail gas is sent to the tail gas incinerator for incineration; 2) Treatment of tail gas of Class A and B products: The operating pressure control range of Class A and B product storage tanks is -0.2~0.4kPa. When the pressure recording and regulating instrument A shows < 0kPa, open the nitrogen self-supporting regulating valve A to replenish nitrogen. When it is < -0.1kPa, open the nitrogen self-supporting regulating valve A to replenish nitrogen. When it is < -0.2kPa, inhale air through the breathing valve. When the pressure recording and regulating instrument A displays > 0.4kPa, it is opened and the excess Class A and B product tail gas is discharged through the pressure regulating valve A, and when the oxygen content analysis instrument displays < 0.5%, the solenoid valve is opened to send the discharged Class A and B product tail gas to the Class A and B product adsorption system for treatment, and the cleaned Class A and B product tail gas is sent to the tail gas incinerator for incineration; 3) Treatment of thermal polycondensation reaction tail gas: The thermal polycondensation reaction tail gas is directly sent to the incinerator for incineration; 4) The furnace temperature of the tail gas incinerator is controlled at 900-1000℃. When the temperature recording and adjusting instrument shows < 900℃, open the flow regulating valve to let in gas and gradually increase the gas volume until the temperature recording and adjusting instrument shows ≦1000℃; While introducing the thermal polycondensation reaction exhaust gas and coal gas, start the air blower to introduce Class C product exhaust gas and air, and use the proportional adjustment flow recording and regulating instrument and the flow recording and regulating instrument to control the ratio of the flow of the thermal polycondensation reaction exhaust gas + coal gas and the flow of the Class C product exhaust gas + air entering the exhaust incinerator to be 1:5.

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