An acid gas recovery auxiliary device

Abstract

This utility model discloses an auxiliary device for acid gas recovery, belonging to the field of acid gas recovery technology in petrochemical plants. The device includes a No. 1 pipeline connected to the top reflux tank of the stripping tower, with No. 2, No. 3, and No. 4 pipelines at its end, which are respectively connected to the reflux pump outlet, the RH pipeline, and the atmosphere. The No. 4 pipeline is connected to the No. 6 pipeline through the No. 5 pipeline. The No. 6 pipeline is used to send the acid gas from the top reflux tank of the de-ethaner tower into the absorption tower. Each pipeline is equipped with a valve group and is connected by stainless steel pipes, elbows, and equal-diameter tees. This device can stabilize the process parameters at the top of the tower, reduce the emission of non-condensable gases, reduce equipment corrosion, improve the acid gas recovery efficiency, adapt to high-load conditions, and has both economic and environmental benefits.

Description

Technical Field

[0001] This utility model relates to the field of acid gas recovery technology in petrochemical plant fractionation systems, specifically to an auxiliary device for acid gas recovery, used to optimize the transportation and recovery process of acid gas from stripping towers, and improve acid gas recovery efficiency and plant operation stability. Background Technology

[0002] In existing petrochemical plant fractionation systems, acid gas is primarily stripped via a stripping tower. The flash vapor phase from the top reflux tank is then piped to the light hydrocarbon desulfurization system for dry gas separation, desulfurization, and recovery. If the stripping tower's separation efficiency is poor, some light hydrocarbons and hydrogen sulfide will enter the fractionation tower with the bottom oil, requiring the pressure control device of the top reflux tank to continuously discharge gas into the flare. Over long-term operation, this exacerbates equipment and pipeline corrosion, threatening safe production. Furthermore, the entry of dry gas into the fractionation tower causes fluctuations in tower operation, while the gas discharged into the low-pressure flare not only reduces the plant's economic efficiency but also poses energy waste and environmental risks. Therefore, an auxiliary device that optimizes the acid gas transport process and improves recovery efficiency is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to provide an auxiliary device for acid gas recovery, which optimizes the acid gas transportation and diversion process, stabilizes the gas phase cooling temperature at the top of the tower, and reduces the amount of non-condensable gas emitted; at the same time, it stabilizes the reflux flow rate at the top of the tower, the top temperature of the tower, and the extraction temperature of the heavy stone side stream, ensuring product quality, reducing the risk of equipment corrosion, and improving the economic benefits and environmental performance of the device.

[0004] To achieve the above objectives, this utility model is implemented through the following technical solution: This utility model discloses an auxiliary device for acid gas recovery, characterized in that it includes a first pipeline connected to the top reflux tank of a stripping tower. The end of the first pipeline is branched into a second, third, and fourth pipeline, each equipped with a valve assembly. The second pipeline is connected to the top reflux pump of the stripping tower to deliver acid gas to the pump outlet. The third and fourth pipelines are respectively connected to the RH pipeline and the atmosphere. Pipeline No. 4 is connected to Pipeline No. 6 via Pipeline No. 5, which is equipped with a valve assembly. One end of Pipeline No. 6 is used to receive acid gas from the top reflux tank of the de-ethane tower, and the other end is used to send the acid gas into the absorption tower.

[0005] Preferably, both the No. 1 pipeline and the No. 2 pipeline are equipped with two shut-off valves and a regulating valve located between the shut-off valves. The two shut-off valves and the regulating valve on the No. 1 pipeline and the No. 2 pipeline constitute the main pipeline. Each of the main pipelines is connected in parallel with a secondary pipeline equipped with a shut-off valve.

[0006] Preferably, the valve groups on pipelines No. 3, No. 5, and No. 6 all include shut-off valves and check valves.

[0007] Preferably, pipelines 1, 2, 3, 4, 5, and 6 are all stainless steel pipes. Preferably, the connection ends of pipeline No. 3 and pipeline No. 4 are both connected by elbows; the connection end of pipeline No. 5 is connected by elbows; and the main pipeline and the secondary pipeline are connected by elbows.

[0008] Preferably, the No. 4 pipeline and the No. 5 pipeline are connected by an equal diameter tee; the No. 5 pipeline and the No. 6 pipeline are connected by an equal diameter tee. Beneficial effects

[0009] Optimize the acid gas delivery path: Acid gas is introduced into the absorption tower through pipeline No. 6. Combined with the diversion of multiple pipelines and valve group control, pressure reduction operating conditions are created for the stripping tower, making the top pressure of the stripping tower controllable, reducing the opening of the external delivery regulating valve, and improving operational stability.

[0010] Reduce flare emissions: The amount of acid gas delivered to external sources is significantly increased, reducing energy consumption losses and improving economic efficiency.

[0011] Reduce corrosion risk: Reduce the amount of acidic gas entering the fractionation tower, alleviate corrosion of equipment and pipelines, extend the service life of the unit, and ensure safe production. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the pipeline connection structure of this utility model. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0014] Technical principles: such as Figure 1 As shown, this application consists of two process flow paths, upper and lower, with the detailed structure as follows: Upper section (top reflux tank side of the stripping tower): Acid gas drawn from the top reflux tank of the stripping tower is transported through pipeline (Pipeline 1). This pipeline has three branches: The first branch (acid gas to the outlet of the top reflux pump of the stripping tower), namely Pipeline 2: The pipeline is equipped with a shut-off valve, a regulating valve, and a shut-off valve in sequence, and is connected in parallel with a secondary pipeline equipped with a shut-off valve; The second branch (to RH, i.e., the Recycled Hydrogen pipeline), namely Pipeline 3: The pipeline is equipped with a shut-off valve, a check valve, and a shut-off valve, introducing acid gas into the recycled hydrogen system, which may participate in subsequent hydrogenation processes to further remove or recover components such as hydrogen sulfide and light hydrocarbons in the acid gas, thereby optimizing the treatment efficiency and resource utilization of acid gas; The third branch (to the atmosphere), namely Pipeline 4: The pipeline is equipped with a shut-off valve and is connected to subsequent new processes through a pipeline with a valve assembly.

[0015] The lower section (acid gas from the top reflux tank of the deethaner): Acid gas drawn from the top reflux tank of the deethaner is transported through pipeline (pipeline 6). The pipeline is equipped with a shut-off valve, a regulating valve, and a shut-off valve in sequence, and a secondary pipeline with a shut-off valve is connected in parallel. This pipeline eventually merges with pipeline 4 in the upper section, sending the acid gas into the absorption tower. The merging point and subsequent pipelines are equipped with valve groups such as shut-off valves, check valves, and shut-off valves.

[0016] Technical solution:

[0017] This invention provides an auxiliary device for acid gas recovery to solve the problems of large emissions, equipment corrosion, and operational fluctuations in existing acid gas recovery processes. The specific structure of the device is as follows: The system includes a No. 1 pipeline connected to the top reflux tank of the stripping tower. The ends of the No. 1 pipeline are connected to the No. 2 pipeline (2), No. 3 pipeline (3), and No. 4 pipeline (4), each equipped with a valve assembly. The No. 2 pipeline connects to the top reflux pump of the stripping tower, used to transport acid gas to the pump outlet. The No. 3 pipeline connects to the RH pipeline, and the No. 4 pipeline connects directly to the atmosphere. The No. 4 pipeline connects to the No. 6 pipeline (6) via the No. 5 pipeline, which is also equipped with a valve assembly. One end of the No. 6 pipeline is used to receive acid gas from the top reflux tank of the de-ethaner tower, and the other end is used to send the acid gas into the absorption tower. Furthermore, each of the No. 1 pipeline 1 and No. 2 pipeline is equipped with two shut-off valves 7 and a regulating valve 8 located between the two shut-off valves 7, and the two shut-off valves 7 and the regulating valve 8 constitute the main pipeline 9; each of the main pipelines is connected in parallel with a secondary pipeline equipped with a shut-off valve 7 (for temporary connection of the main pipeline during maintenance). The valve groups of the No. 3 pipeline 3, No. 5 pipeline 5, and No. 6 pipeline 6 all include shut-off valves and check valves (the shut-off valve is used to control the on / off state, and the check valve prevents the fluid from flowing backward). The No. 1 pipeline 1, No. 2 pipeline 2, No. 3 pipeline 3, No. 4 pipeline 4, No. 5 pipeline 5, and No. 6 pipeline 6 are all made of stainless steel pipes (to improve corrosion resistance and adapt to acidic gas environments). The connection ends of the No. 3 pipeline 3 and No. 4 pipeline 4 are all connected by elbows; the connection end of the No. 5 pipeline 5 is also connected by elbows; the main pipeline and the secondary pipeline are connected by elbows (to reduce fluid resistance and ensure smooth transportation). The fourth pipeline 4 and the fifth pipeline 5 are connected by an equal-diameter tee; the fifth pipeline 5 and the sixth pipeline 6 are connected by an equal-diameter tee (to achieve stable diversion and convergence of multiple pipelines).

[0018] Example 1: The core of this acid gas recovery auxiliary device is to achieve the rational transportation and recovery of acid gas through multi-pipeline diversion and valve control. The specific connection and operation process is as follows: Pipeline 1 connects to the top reflux tank of the stripping tower to draw out the acidic gas from the top of the stripping tower. Its ends connect to Pipelines 2, 3, and 4 via a branching structure. Each pipeline is equipped with valve assemblies to control on / off flow and volume. Pipeline 2 connects to the outlet of the stripping tower top reflux pump. Through two shut-off valves, an intermediate regulating valve, and a parallel auxiliary pipeline (with a shut-off valve), the delivery of acidic gas to the reflux pump outlet can be flexibly controlled to meet the process requirements of the reflux system. Pipeline 3 connects to the RH pipeline. The shut-off valve and check valve on the pipeline work together to achieve directional delivery of acidic gas to the RH system, preventing backflow. Pipeline 4 connects directly to the atmosphere as an emergency discharge channel. Simultaneously, Pipeline 4 connects to Pipeline 6 via Pipeline 5 (with a shut-off valve and check valve). All connections between Pipeline 5 and Pipelines 4 and 6 use equal-diameter tees to ensure smooth fluid distribution and merging. One end of pipeline 6 is connected to the acid gas from the top reflux tank of the de-ethane tower, and the other end is connected to the absorption tower. The valve group (stop valve and check valve) on the pipeline controls the delivery of acid gas to the absorption tower, so as to achieve efficient recovery of acid gas.

[0019] All pipelines are made of stainless steel, with connections made via elbows or equal-diameter tees to reduce fluid resistance and improve corrosion resistance. During operation, the delivery path and flow rate of acid gas can be flexibly controlled by adjusting the opening of each valve group, enabling pressure reduction operation of the stripping tower, reducing flare emissions, stabilizing process parameters at the top of the tower, and ensuring product quality compliance.

[0020] The specific advantages of this application are as follows: Optimized acid gas delivery path: By introducing acid gas into the absorption tower through the addition of a new No. 6 pipeline, combined with multi-pipeline diversion and valve group control, pressure reduction operating conditions are created for the stripping tower, making the top pressure of the stripping tower controllable (e.g., from 1.27MPa to 1.10MPa), and reducing the opening of the external control valve (e.g., from fully open to 54%), thus improving operational stability; Reduced flare emissions: The external acid gas delivery volume is significantly increased (e.g., an average increase of 700 Nm³ / h), corresponding to a reduction of 700 Nm³ / h in flare emissions, reducing energy loss and improving economic efficiency; Reduced corrosion risk: The amount of acid gas entering the fractionation tower is reduced, alleviating corrosion of equipment and pipelines, extending the service life of the unit, and ensuring safe production; Adaptability to complex operating conditions: It can stabilize relevant process parameters at the top of the tower (reflux flow, temperature, etc.), ensuring product quality, adapting to high-load, high-conversion-rate operating conditions, and combining environmental benefits with economic value.

[0021] Finally, it should be noted that this utility model is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. An auxiliary device for acid gas recovery, characterized in that, The system includes a No. 1 pipeline (1) connecting to the top reflux tank of the stripping tower. The end of the No. 1 pipeline (1) is equipped with a No. 2 pipeline (2), a No. 3 pipeline (3), and a No. 4 pipeline (4), each with a valve assembly. The No. 2 pipeline (2) is connected to the top reflux pump of the stripping tower to deliver acid gas to the outlet of the top reflux pump. The No. 3 pipeline (3) and the No. 4 pipeline (4) are respectively connected to the RH pipeline and the atmosphere. The fourth pipeline (4) is connected to the sixth pipeline (6) via the fifth pipeline (5) with a valve group. The sixth pipeline (6) is equipped with a valve group, and one end of the sixth pipeline (6) is used to connect to the acid gas from the top reflux tank of the de-ethane tower, and the other end is used to send the acid gas into the absorption tower.

2. The acid gas recovery auxiliary device according to claim 1, characterized in that, Both pipeline No. 1 (1) and pipeline No. 2 (2) are equipped with two shut-off valves and a regulating valve located between the shut-off valves. The two shut-off valves and the regulating valve on pipeline No. 1 (1) and pipeline No. 2 (2) constitute the main pipeline. Each of the main pipelines is connected in parallel with a secondary pipeline equipped with a shut-off valve.

3. An auxiliary device for acid gas recovery according to claim 1 or 2, characterized in that, The valve groups on pipeline No. 3 (3), pipeline No. 5 (5), and pipeline No. 6 (6) all include shut-off valves and check valves.

4. The acid gas recovery auxiliary device according to claim 3, characterized in that, The No. 1 pipeline (1), No. 2 pipeline (2), No. 3 pipeline (3), No. 4 pipeline (4), No. 5 pipeline (5), and No. 6 pipeline (6) are all stainless steel pipes.

5. An auxiliary device for acid gas recovery according to claim 2, characterized in that, The connection ends of pipeline No. 3 (3) and pipeline No. 4 (4) are all connected by elbows; the connection end of pipeline No. 5 (5) is connected by elbows; the main pipeline and the secondary pipeline are connected by elbows.

6. The acid gas recovery auxiliary device according to claim 4, characterized in that, The No. 4 pipeline (4) and the No. 5 pipeline (5) are connected by an equal diameter tee; the No. 5 pipeline (5) and the No. 6 pipeline (6) are connected by an equal diameter tee.

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