Coking loading tail gas recovery treatment system and process

Abstract

The invention relates to a coking loading tail gas recovery treatment system which comprises a loading crane pipe with a tail gas recovery function, a tail gas header pipe pressure adjusting system, a nitrogen injection system, a tail gas buffer tank, a tail gas pipeline steam blowing and heat tracing heat preservation system, an oxygen content detection and emergency cut-off system and a nitrogen pipeline. The loading crane pipe is connected with the tail gas header pipe pressure adjusting system and is connected to the nitrogen injection system; the nitrogen pipeline is also connected to the nitrogen injection system; the nitrogen injection system, the tail gas buffer tank and the oxygen content detection and emergency cut-off system are connected in sequence; the content detection and emergency cut-off system performs cut-off action according to a set oxygen content upper limit; the tail gas pipeline steam blowing and heat tracing heat preservation system conducts steam blowing and heat tracing on the exterior of a pipeline containing tail gas.

Description

Technical Field

[0001] The invention relates to a method for treating tail gas from coking loading, in particular to a system and process for recovering and treating tail gas from coking loading. Background Art

[0002] The chemical production workshop of the coking plant of the steel company has many chemical products such as crude benzene, washing oil, anthracene oil and other truck loading operations. Since domestic enterprises have not completely achieved closed loading and unloading during the material loading and unloading process, some enterprises usually directly open the manhole on the roof during the unloading process, resulting in a large amount of air entering the tank truck. When the material is loaded again, it will produce loading tail gas containing about 18-20% oxygen. Due to the high oxygen content and high combustible medium components in the tail gas, it can neither be directly entered into the gas negative pressure system for recovery nor sent to the incinerator for incineration. At present, most enterprises use solvent washing to directly release the exhaust gas from loading into the air, but its non-methane total hydrocarbon content far exceeds the existing national standards. Another part of enterprises uses the process of "deep condensation + activated carbon / carbon fiber adsorption / incineration" to treat the exhaust gas from loading benzene, but there are certain problems in the operation process, mainly manifested as: 1) The cooling temperature does not reach the design value, and the exhaust gas outlet emission index does not meet the standard; 2) Due to the complex composition of the exhaust gas and the presence of a certain amount of naphthalene and other easily crystallized substances, it is very easy to cause the heat exchange tube bundle for deep condensation to be blocked, and it is inconvenient to clean. 3) The problem of high one-time investment and operating costs. Summary of the invention

[0003] The present invention provides a coking loading tail gas recovery and treatment system and process, which mainly consists of a loading crane with tail gas recovery, a tail gas main pressure regulating system, a nitrogen injection system, a tail gas buffer tank, a tail gas pipeline steam purge and heating and insulation system, an oxygen content detection and emergency cut-off system, etc. The system uses nitrogen as a power source to introduce the loading tail gas into the system and uses nitrogen as an inert gas to dilute the oxygen content in the loading tail gas so that it meets the conditions for introducing the coal gas negative pressure system, thereby solving the current problem of coking loading tail gas treatment.

[0004] The purpose of the present invention is to solve the problem that the existing loading exhaust gas has a high oxygen content and cannot directly enter the coal gas negative pressure system for recovery and treatment, while the "deep condensation + activated carbon / carbon fiber adsorption / incineration" treatment process has many disadvantages and cannot treat the loading exhaust gas of other easily crystallized media such as tar and naphthalene oil.

[0005] The present invention adopts the following technical solutions:

[0006] A coking loading tail gas recovery and treatment system comprises a loading crane with tail gas recovery, a tail gas main pressure regulating system, a nitrogen ejection system, a tail gas buffer tank, a tail gas pipeline steam purging and heating and insulation system, an oxygen content detection and emergency shut-off system, and a nitrogen pipeline; the loading crane and the tail gas main pressure regulating system are connected and connected to the nitrogen ejection system; the nitrogen pipeline is also connected to the nitrogen ejection system; the tail gas buffer tank and the oxygen content detection and emergency shut-off system of the nitrogen ejection system are connected in sequence; the content detection and emergency shut-off system performs a shut-off action according to a set upper limit of oxygen content; the tail gas pipeline steam purging and heating and insulation system performs steam purging and heating on the outside of the pipeline containing tail gas.

[0007] Preferably, the loading crane pipe includes a Class A and B liquid truck loading crane pipe and a Class C liquid truck loading crane pipe, and all loading crane pipes are connected in parallel; the Class A and B liquid truck loading crane pipes are connected to the exhaust gas main pressure regulating system through a loading exhaust gas pipeline, and a flame arrester is provided on the Class A and B liquid loading exhaust gas pipeline; the Class C liquid truck loading crane pipe is connected to the exhaust gas main pressure regulating system through a loading exhaust gas pipeline, and no flame arrester is provided on the Class C liquid loading exhaust gas pipeline.

[0008] Preferably, the rear of the oxygen content detection and emergency shut-off system is connected to the exhaust gas collecting main pipe, and a discharge channel is provided between the two.

[0009] Preferably, the nitrogen injection system is a Venturi structure, wherein the nitrogen pipeline is the inlet channel of the Venturi structure, and the pipeline where the exhaust manifold pressure regulating system is located is the negative pressure suction channel of the Venturi structure.

[0010] Preferably, gate valves are provided at the front and rear parts of the tail gas buffer tank.

[0011] Furthermore, the front of the Class A and B liquid loading exhaust pipeline and the Class C liquid loading exhaust pipeline are both provided with gate valves, and the front of the steam purge and heating and insulation system is provided with a stop valve.

[0012] A coking loading tail gas recovery and treatment process uses the above-mentioned coking loading tail gas recovery and treatment system; the loading tail gas generated by the automobile tank truck is collected in a closed manner through a loading crane with tail gas recovery and related pipelines; the collected loading tail gas is injected into the tail gas collection system under the action of negative pressure formed by a nitrogen injection system and is fully mixed with nitrogen and then enters the tail gas buffer tank for further mixing; the mixed tail gas is sent to the coal gas negative pressure system after being tested by an online oxygen content detector; when the oxygen content exceeds the standard, the tail gas main line to the coal gas negative pressure system is quickly cut off, and the tail gas is discharged through a vent pipe instead; the tail gas main pipe pressure regulating system arranged between the loading crane and the nitrogen injection system accurately controls the negative pressure in the tank truck, i.e., the tail gas suction force.

[0013] Preferably, the method specifically comprises the following steps:

[0014] S1. Reliably connect the loading crane pipe with exhaust gas recovery to the tank truck, and turn on the steam heating system of the exhaust gas pipeline;

[0015] S2. Start the loading exhaust gas treatment system with one button, and the loading exhaust gas treatment system automatically performs the following operations;

[0016] S21, close the quick cut-off valve on the exhaust main pipe, and open the quick release valve on the exhaust main pipe at the same time;

[0017] S22, gradually opening the nitrogen flow regulating valve in the nitrogen injection system until the flow meter reaches a first set value;

[0018] S23, when the reading of the online oxygen content detector reaches the second set value, close the quick release valve on the tail gas main pipe, and open the quick cut-off valve on the tail gas main pipe to introduce the tail gas into the gas negative pressure system, and interlock the quick release valve, the quick cut-off valve and the online oxygen content detector;

[0019] S24, putting the tail gas pressure regulating valve at the tail gas inlet pipe into automatic state, controlling the reading of the pressure transmitter in front of the pressure regulating valve to reach a third setting value, and introducing the loading tail gas into the gas negative pressure system;

[0020] S25. When the reading of the online oxygen content detector reaches the fourth setting value, close the quick cut-off valve on the exhaust main pipe, and open the quick release valve on the exhaust main pipe to release the exhaust gas into the air;

[0021] S26, increasing the opening of the nitrogen flow regulating valve in the nitrogen injection system until the flow meter reaches the fifth setting value, and then purging and replacing the exhaust gas pipeline;

[0022] S27. When the reading of the online oxygen content detector returns to the second setting value, close the quick release valve on the tail gas main pipe, and open the quick cut-off valve on the tail gas main pipe, continue to introduce the tail gas into the gas negative pressure system, and interlock the quick release valve, the quick cut-off valve and the online oxygen content detector; at the same time, gradually reduce the opening of the nitrogen flow regulating valve until the nitrogen flow reaches the first setting value;

[0023] S28. When loading is completed, the loading exhaust gas treatment system is turned off with one button, and the nitrogen flow regulating valve is closed;

[0024] S3. Disconnect the loading crane pipe with exhaust gas recovery from the tank truck, and shut down the steam heating system of the exhaust gas pipeline.

[0025] The beneficial effects of the present invention are:

[0026] 1) The closed recovery of coking loading tail gas is realized, so that the coking loading tail gas is safely and effectively treated.

[0027] 2) It realizes one-button start and stop, automatic collection and treatment of vehicle exhaust. Under normal circumstances, there is basically no need for human intervention in the process.

[0028] 3) A variety of anti-pipeline blockage methods (such as steam heating) are used to effectively prevent pipeline blockage, reduce the occurrence of pipeline blockage, and reduce the workload of daily inspection and maintenance.

[0029] 4) The system is simple, and the project investment and operating costs are low. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the coking loading tail gas recovery and treatment system of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0032] The present invention intends to adopt nitrogen injection mixing + negative pressure tail gas recovery process to recycle the loading tail gas, which is mainly composed of a loading crane with tail gas recovery, a tail gas main pressure regulating system, a nitrogen injection system, a tail gas buffer tank, a tail gas pipeline steam purge and heating insulation system, an oxygen content detection and emergency shut-off system, etc.

[0033] It can achieve the following functions:

[0034] Use a loading crane with exhaust gas recovery to recover the exhaust gas from loading in a closed manner;

[0035] A nitrogen injection system is used to form negative pressure, so that the exhaust gas from the loading vehicle is sucked into the system and fully mixed with the nitrogen;

[0036] The tail gas main pressure regulating valve is used to control the negative pressure value in the automobile tank to ensure the safety of the tank truck;

[0037] Equipped with online oxygen content detection and emergency cut-off system to strictly control oxygen content and avoid the influence of oxygen content in tail gas on gas refining system;

[0038] Steam heating, steam purging and condensate discharge measures are set up to prevent impurities such as naphthalene and tar in the coking tail gas from crystallizing and clogging the pipeline.

[0039] See also Figure 1, a coking loading tail gas recovery and treatment system, comprising a loading crane with tail gas recovery, a tail gas main pressure regulating system, a nitrogen ejection system, a tail gas buffer tank, a tail gas pipeline steam purging and heating and insulation system, an oxygen content detection and emergency shut-off system, and a nitrogen pipeline; the loading crane and the tail gas main pressure regulating system are connected and connected to the nitrogen ejection system; the nitrogen pipeline is also connected to the nitrogen ejection system; the tail gas buffer tank and the oxygen content detection and emergency shut-off system of the nitrogen ejection system are connected in sequence; the content detection and emergency shut-off system performs a shut-off action according to a set upper limit of oxygen content; the tail gas pipeline steam purging and heating and insulation system performs steam purging and heating on the outside of the pipeline containing tail gas.

[0040] See also Figure 1 The loading crane pipe includes a Class A and B liquid truck loading crane pipe and a Class C liquid truck loading crane pipe, and the two are connected in parallel; the Class A and B liquid truck loading crane pipe is connected to the exhaust gas main pressure regulating system through a loading exhaust gas pipeline, and a flame arrester is provided on the Class A and B liquid loading exhaust gas pipeline; the Class C liquid truck loading crane pipe is connected to the exhaust gas main pressure regulating system through a loading exhaust gas pipeline, and no flame arrester is provided on the Class C liquid loading exhaust gas pipeline.

[0041] See also Figure 1 The rear of the oxygen content detection and emergency shut-off system is connected to the waste collection main pipe, and a discharge channel is provided between the two.

[0042] In this embodiment, the nitrogen injection system is a Venturi structure, wherein the nitrogen pipeline is the inlet channel of the Venturi structure, and the pipeline where the exhaust manifold pressure regulating system is located is the negative pressure suction channel of the Venturi structure. The principle of the Venturi structure belongs to the prior art, so this article will not elaborate on its principle.

[0043] See also Figure 1 The front and rear parts of the tail gas buffer tank are both provided with gate valves.

[0044] Continue to see Figure 1 The front parts of the crude benzene loading tail gas pipeline and the tar loading tail gas pipeline are both provided with gate valves, and the front part of the steam purge and heating and insulation system is provided with a stop valve.

[0045] A coking loading tail gas recovery and treatment process, the loading tail gas generated by the automobile tank truck is collected in a closed manner through a loading crane with tail gas recovery and related pipelines, the collected loading tail gas is injected into the tail gas collection system under the action of negative pressure formed by a nitrogen injection system and fully mixed with nitrogen, and then enters the tail gas buffer tank for further mixing; the mixed tail gas is sent to the coal gas negative pressure system after being tested by an online oxygen content detector; when the oxygen content exceeds the standard, the tail gas main line to the coal gas negative pressure system is quickly cut off, and the tail gas is discharged through a vent pipe instead; the tail gas main pipe pressure regulating system arranged between the loading crane and the nitrogen injection system accurately controls the negative pressure in the tank truck, that is, the tail gas suction force.

[0046] The specific steps include:

[0047] S1. Reliably connect the loading crane pipe with exhaust gas recovery to the tank truck, and turn on the steam heating system of the exhaust gas pipeline;

[0048] S2. Start the loading exhaust gas treatment system with one button, and the loading exhaust gas treatment system automatically performs the following operations;

[0049] S21, close the quick cut-off valve on the exhaust main pipe, and open the quick release valve on the exhaust main pipe at the same time;

[0050] S22, gradually opening the nitrogen flow regulating valve in the nitrogen injection system until the flow meter reaches a first set value;

[0051] S23, when the reading of the online oxygen content detector reaches the second set value, close the quick release valve on the tail gas main pipe, and open the quick cut-off valve on the tail gas main pipe to introduce the tail gas into the gas negative pressure system, and interlock the quick release valve, the quick cut-off valve and the online oxygen content detector;

[0052] S24, putting the tail gas pressure regulating valve at the tail gas inlet pipe into automatic state, controlling the reading of the pressure transmitter in front of the pressure regulating valve to reach a third setting value, and introducing the loading tail gas into the gas negative pressure system;

[0053] S25. When the reading of the online oxygen content detector reaches the fourth setting value, close the quick cut-off valve on the exhaust main pipe, and open the quick release valve on the exhaust main pipe to release the exhaust gas into the air;

[0054] S26, increasing the opening of the nitrogen flow regulating valve in the nitrogen injection system until the flow meter reaches the fifth setting value, and then purging and replacing the exhaust gas pipeline;

[0055] S27. When the reading of the online oxygen content detector returns to the second setting value, close the quick release valve on the tail gas main pipe, and open the quick cut-off valve on the tail gas main pipe, continue to introduce the tail gas into the gas negative pressure system, and interlock the quick release valve, the quick cut-off valve and the online oxygen content detector; at the same time, gradually reduce the opening of the nitrogen flow regulating valve until the nitrogen flow reaches the first setting value;

[0056] S28. When loading is completed, the loading exhaust gas treatment system is turned off with one button, and the nitrogen flow regulating valve is closed;

[0057] S3. Disconnect the loading crane pipe with exhaust gas recovery from the tank truck, and shut down the steam heating system of the exhaust gas pipeline.

[0058] The above are preferred embodiments of the present invention. A person skilled in the art may make various changes or improvements on this basis. Without departing from the general concept of the present invention, these changes or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. A coking loading tail gas recovery and treatment system, characterized by: Including loading crane with exhaust gas recovery, exhaust gas main pressure regulating system, nitrogen injection system, exhaust gas buffer tank, exhaust gas pipeline steam purge and heating insulation system, oxygen content detection and emergency shut-off system, nitrogen pipeline; The loading crane pipe and the tail gas main pressure regulating system are connected and connected to the nitrogen injection system; the nitrogen pipeline is also connected to the nitrogen injection system; The tail gas buffer tank of the nitrogen injection system and the oxygen content detection and emergency shutoff system are connected in sequence; the content detection and emergency shutoff system performs a shutoff action according to a set upper limit of oxygen content; The tail gas pipeline steam purging and heating and insulation system performs steam purging and heating on the outside of the pipeline containing the tail gas.

2. The coking loading tail gas recovery and treatment system according to claim 1, characterized in that: The loading crane pipes include Class A and B liquid truck loading crane pipes and Class C liquid truck loading crane pipes, and all loading crane pipes are connected in parallel; The Class A and B liquid truck loading crane pipe is connected to the exhaust gas main pressure regulating system through a loading exhaust gas pipeline, and a flame arrester is provided on the Class A and B liquid truck loading exhaust gas pipeline; The Class C liquid truck loading crane pipe is connected to the exhaust gas main pressure regulating system through a loading exhaust gas pipeline, and no flame arrester is provided on the Class C liquid truck loading exhaust gas pipeline.

3. The coking loading tail gas recovery and treatment system according to claim 1, characterized in that: The rear of the oxygen content detection and emergency shut-off system is connected to the exhaust gas collecting main pipe, and a discharge channel is provided between the two.

4. The coking loading tail gas recovery and treatment system according to claim 1, characterized in that: The nitrogen injection system is a Venturi structure, wherein the nitrogen pipeline is the inlet channel of the Venturi structure, and the pipeline where the tail gas main pressure regulating system is located is the negative pressure suction channel of the Venturi structure.

5. The coking loading tail gas recovery and treatment system according to claim 2, characterized in that: Gate valves are provided at the front and rear parts of the tail gas buffer tank.

6. The coking loading tail gas recovery and treatment system according to claim 5, characterized in that: A gate valve is provided at the front of the loading exhaust gas pipeline, and a stop valve is provided at the front of the steam purge and heating and insulation system.

7. A coking loading tail gas recovery and treatment process, characterized in that: Use the coking loading tail gas recovery and treatment system described in any one of claims 1 to 6; The loading tail gas generated by the tank truck is collected in a closed manner through the loading crane pipe with tail gas recovery and related pipelines. The collected loading tail gas is injected into the tail gas collection system under the negative pressure formed by the nitrogen injection system and fully mixed with nitrogen before entering the tail gas buffer tank for further mixing; the mixed tail gas is sent to the gas negative pressure system after being tested by the online oxygen content detector; When the oxygen content exceeds the standard, the tail gas main line to the gas negative pressure system is quickly cut off, and the tail gas is discharged through the vent pipe instead; The exhaust gas main pressure regulating system installed between the loading crane pipe and the nitrogen injection system accurately controls the negative pressure inside the tank truck, that is, the exhaust gas suction force.

8. The coking loading tail gas recovery and treatment process according to claim 7, characterized in that: The specific steps include: S1. Reliably connect the loading crane pipe with exhaust gas recovery to the tank truck, and turn on the steam heating system of the exhaust gas pipeline; S2. Start the loading exhaust gas treatment system with one button, and the loading exhaust gas treatment system automatically performs the following operations; S21, close the quick cut-off valve on the exhaust main pipe, and open the quick release valve on the exhaust main pipe at the same time; S22, gradually opening the nitrogen flow regulating valve in the nitrogen injection system until the flow meter reaches a first set value; S23, when the reading of the online oxygen content detector reaches the second set value, close the quick release valve on the tail gas main pipe, and open the quick cut-off valve on the tail gas main pipe to introduce the tail gas into the gas negative pressure system, and interlock the quick release valve, the quick cut-off valve and the online oxygen content detector; S24, putting the tail gas pressure regulating valve at the tail gas inlet pipe into automatic state, controlling the reading of the pressure transmitter in front of the pressure regulating valve to reach a third setting value, and introducing the loading tail gas into the gas negative pressure system; S25. When the reading of the online oxygen content detector reaches the fourth setting value, close the quick cut-off valve on the exhaust main pipe, and open the quick release valve on the exhaust main pipe to release the exhaust gas into the air; S26, increasing the opening of the nitrogen flow regulating valve in the nitrogen injection system until the flow meter reaches the fifth setting value, and then purging and replacing the exhaust gas pipeline; S27. When the reading of the online oxygen content detector returns to the second setting value, close the quick release valve on the tail gas main pipe, and open the quick cut-off valve on the tail gas main pipe, continue to introduce the tail gas into the gas negative pressure system, and interlock the quick release valve, the quick cut-off valve and the online oxygen content detector; at the same time, gradually reduce the opening of the nitrogen flow regulating valve until the nitrogen flow reaches the first setting value; S28. When loading is completed, the loading exhaust gas treatment system is turned off with one button, and the nitrogen flow regulating valve is closed; S3. Disconnect the loading crane pipe with exhaust gas recovery from the tank truck, and shut down the steam heating system of the exhaust gas pipeline.

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