Chemical plant waste acid direct feeding system

Abstract

The application discloses a chemical device waste acid direct sending system, belongs to the field of fine chemical industry, is suitable for methyl methacrylate (MMA) device by-product waste acid treatment, and aims at the problems of pipeline blockage, waste gas escape, high maintenance cost and unstable transportation caused by the secondary transportation of waste acid through a storage tank in the prior art. The system additionally arranges a forced circulation pump and a waste acid direct sending pump in a waste acid transportation path, is respectively configured in a 'two open one standby' mode and a 'one open two standby' mode, can accurately control a circulation amount, can cooperate with the use of a circulating shear force to disperse asphaltene in waste acid, can realize waste acid homogenization, and can directly transport the homogenized waste acid to a sulfuric acid device incinerator through an independent direct sending process without entering a buffer tank. The system effectively solves the problems of waste acid flow fluctuation and component unevenness, eliminates waste gas escape, reduces maintenance frequency and labor intensity, guarantees long-period stable operation of the incinerator, has remarkable economic and environmental benefits, and has wide popularization value.

Description

Technical Field

[0001] This invention relates to the field of fine chemicals, specifically to a waste acid direct delivery system for chemical plants, which is particularly suitable for the stable delivery and incineration of waste acid by-products from methyl methacrylate (MMA) plants, and can effectively solve problems such as blockage and flow fluctuations in the waste acid delivery process. Background Technology

[0002] The No. 1 90,000-ton / year MMA unit in the first phase of the 40 million tons / year integrated refining and chemical project of Zhejiang Petrochemical Co., Ltd. has an operating flexibility of 60-110% and a designed annual operating time of 8,000 hours. It adopts the proprietary acetone cyanohydrin (ACH) process production technology developed by Liaoning Acrylic Casting Plate Co., Ltd. This unit uses hydrogen cyanide (HCN) from the acrylonitrile unit, acetone from the phenol / acetone unit, and methanol from the atmospheric pressure tank area of ​​the refinery as main raw materials. MMA is produced through ACH synthesis, concentrated sulfuric acid treatment, and esterification reactions. The by-product waste acid is sent to the sulfuric acid unit for incineration to recover the finished sulfuric acid, which is then recycled back to the MMA unit.

[0003] The current industry practice involves collecting waste acid in storage tanks and then pumping it to a sulfuric acid incinerator. However, this process has significant drawbacks: asphaltenes and methyl methacrylate carried in the waste acid accumulate in the tanks over time, easily undergoing polymerization reactions. This can lead to blockages in the tail gas system pipelines, preventing the waste gas from being properly delivered to the sulfuric acid incinerator. Large amounts of waste gas escape from the tank's breather valves, causing environmental incidents. Furthermore, highly viscous polymers tend to deposit at the bottom of the tanks, requiring cleaning during major overhauls. This not only carries high operational risks but also consumes significant manpower and resources, has a long cleaning cycle, and severely impacts the normal operation of the unit. In addition, the waste acid flow rates on lines A and B of the MMA unit fluctuate greatly, and asphaltenes tend to accumulate, leading to unstable waste acid delivery and severely affecting the safe and stable operation of the downstream sulfuric acid incinerator. Summary of the Invention

[0004] To address the problems of large flow fluctuations, asphalt accumulation, pipeline blockage, waste gas leakage, and high maintenance costs in the existing technology of waste acid transportation in MMA units, this invention provides a waste acid direct delivery system for chemical plants. By optimizing the waste acid transportation process and equipment configuration, it achieves stable waste acid flow, ensures the safe, stable, and long-term operation of the sulfuric acid plant incinerator, reduces the probability of environmental incidents, reduces maintenance frequency and manpower and material consumption, and maximizes the company's interests.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention discloses a waste acid direct delivery system for a chemical plant, comprising a sulfuric acid plant incinerator and a waste acid direct delivery unit with a waste acid circulation unit. The waste acid direct delivery unit is connected to the sulfuric acid plant incinerator to achieve directional delivery and incineration of waste acid. The waste acid direct delivery unit includes tanks A Z-12106A and B Z-12106B connected in parallel. Tanks A Z-12106A and B Z-12106B are respectively connected to waste acid direct delivery pumps AP-12107A and BP-12107B via pipelines 1 and 2, respectively. The outlets of waste acid direct delivery pumps AP-12107A and BP-12107B are connected to pipeline 3. Pipeline 4 connects pipelines 1 and 2, and a waste acid direct delivery pump S is connected between pipelines 3 and 4. The P-12107S pipeline, the sulfuric acid unit incinerator is connected to pipeline number three.

[0006] Preferably, the waste acid circulation unit includes waste acid circulation pump AP-12106A, waste acid circulation pump BP-12106B, and waste acid circulation pump SP-12106S. Waste acid circulation pump AP-12106A is connected to tank AZ-12106A via pipeline to form a circulation loop. Waste acid circulation pump BP-12106B is connected to tank BZ-12106B via pipeline to form a circulation loop. Pipeline No. 6 is connected between the pipelines at the inlet ends of waste acid circulation pumps AP-12106A and BP-12106B. Pipeline No. 7 is connected between the pipelines at the outlet ends of waste acid circulation pumps AP-12106A and BP-12106B. Pipeline SP-12106S is connected between pipelines No. 6 and No. 7.

[0007] Preferably, a return tank regulating valve AV-21 is connected to the pipeline at the outlet end of the waste acid circulation pump AP-12106A, and a return tank regulating valve BV-22 is connected to the pipeline at the outlet end of the waste acid circulation pump BP-12106B. The return tank regulating valves AV-21 and BV-22 can control the circulation volume at 130-150t / h.

[0008] Preferably, the sulfuric acid incinerator includes incinerator A and incinerator B, which are respectively connected to pipeline No. 3 via pipelines to realize the corresponding connection between the waste acid direct delivery unit and the incinerator.

[0009] Preferably, the waste acid direct delivery pump SP-12107S can be switched to use when the waste acid direct delivery pump AP-12107A or the waste acid direct delivery pump BP-12107B fails, so as to ensure continuous connection between the waste acid direct delivery unit and the incinerator.

[0010] Preferably, a check valve is connected to the pipeline at the outlet end of the waste acid circulation pump AP-12106A and the pipeline at the outlet end of the waste acid circulation pump BP-12106B to prevent waste acid backflow.

[0011] Preferably, the No. 1 pipeline, the No. 2 pipeline, the No. 3 pipeline, and the pipeline equipped with the waste acid direct delivery pump SP-12107S are each equipped with a flow monitoring instrument to monitor the flow rate of waste acid from the waste acid direct delivery unit to the incinerator in real time.

[0012] Preferably, the waste acid direct delivery unit can form a 1-on, 2-standby operation state among the waste acid direct delivery pumps AP-12107A, AP-12107B, and SP-12107S.

[0013] Preferably, the waste acid circulation pumps AP-12106A, BP-12106B, and SP-12106S in the waste acid circulation unit can form a 2-on-1-standby operating state.

[0014] Preferably, the inner walls of tank A Z-12106A and tank B Z-12106B are provided with a corrosion-resistant coating. Beneficial effects

[0015] Stable and reliable delivery: It can realize the configuration of 2 on and 1 standby through the waste acid circulation unit and the precise circulation volume control of 130-150t / h, as well as the design of 1 on and 2 standby in conjunction with the waste acid direct delivery unit and flow monitoring, effectively solving the problem of waste acid flow fluctuation and ensuring the stable delivery of waste acid to the incinerator.

[0016] High environmental safety: Waste acid is directly transported to the incinerator via the direct delivery unit, eliminating the need for secondary transport through the waste acid buffer tank. This completely eliminates tail gas pipeline blockage caused by MMA polymerization, reduces waste gas leakage, ensures normal operation of the breather valve, and meets environmental protection and safe production requirements.

[0017] Reduced operation and maintenance costs: It avoids polymer deposition in the waste acid tank, reduces the frequency of opening and cleaning the waste acid tank, shortens the equipment maintenance cycle, reduces the labor intensity of employees, and at the same time extends the overall operation cycle of the equipment, thus improving economic efficiency.

[0018] High adaptability: The system has a reasonable structural design and can be widely applied to various chemical waste acid transportation scenarios containing easily polymerizable impurities. It is especially suitable for the waste acid treatment needs of MMA units and has significant promotional value. Attached Figure Description

[0019] Figure 1 This is a block diagram illustrating the principle of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Invention content / principle: System Overall Architecture: The waste acid direct delivery system for chemical plants of this invention includes a sulfuric acid plant incinerator and a waste acid direct delivery unit with a waste acid circulation unit. The waste acid direct delivery unit is connected to the sulfuric acid plant incinerator to realize the directional delivery and incineration of waste acid. Waste acid direct delivery unit structure: The waste acid direct delivery unit includes tanks AZ-12106A and BZ-12106B connected in parallel. Tank AZ-12106A is connected to waste acid direct delivery pump AP-12107A via pipeline No. 1, and tank BZ-12106B is connected to waste acid direct delivery pump BP-12107B via pipeline No. 2. The outlets of waste acid direct delivery pumps AP-12107A and BP-12107B are connected to pipeline No. 3. Pipeline No. 4 connects pipelines No. 1 and No. 2, and pipelines No. 3 and No. 4 connect to a pipeline carrying waste acid direct delivery pump SP-12107S. The sulfuric acid plant incinerator is connected to pipeline No. 3, and includes incinerator A and incinerator B, which are respectively connected to pipeline No. 3, realizing the corresponding connection between the waste acid direct delivery unit and the incinerator. In the waste acid direct delivery unit, waste acid direct delivery pumps AP-12107A, BP-12107B, and SP-12107S can operate in a 1-on, 2-backup configuration (one pump is on, the other two are off and on standby). The SP-12107S pump can be switched in case of a failure of either AP-12107A or BP-12107B, ensuring continuous connection between the waste acid direct delivery unit and the incinerator. Flow monitoring instruments are installed on pipelines 1, 2, and 3, as well as on the pipeline containing the SP-12107S pump, to monitor the flow rate of waste acid from the waste acid direct delivery unit to the incinerator in real time. The inner walls of tanks AZ-12106A and BZ-12106B are coated with a corrosion-resistant layer to extend the equipment's service life.

[0023] Waste acid circulation unit structure: The waste acid circulation unit includes waste acid circulation pumps AP-12106A, BP-12106B, and SP-12106S. Waste acid circulation pump AP-12106A is connected to tank AZ-12106A via pipeline to form a circulation loop, and waste acid circulation pump BP-12106B is connected to tank BZ-12106B via pipeline to form a circulation loop. Pipeline No. 6 connects the inlet pipelines of waste acid circulation pumps AP-12106A and BP-12106B, and pipeline No. 7 connects the outlet pipelines of the two pumps. Pipeline No. 6 and pipeline No. 7 connect to the pipeline of waste acid circulation pump SP-12106S. A return flow regulating valve AV-21 is connected to the outlet pipeline of waste acid circulation pump AP-12106A, and a return flow regulating valve BV-22 is connected to the outlet pipeline of waste acid circulation pump BP-12106B. Both valves AV-21 and BV-22 can control the circulation rate at 130-150 t / h. Check valves are connected to the outlet pipelines of both waste acid circulation pumps AP-12106A and BP-12106B to prevent waste acid backflow. In the waste acid circulation unit, waste acid circulation pumps AP-12106A, BP-12106B, and SP-12106S can operate in a 2-on-1-standby configuration (2 open, 1 closed on standby), ensuring a stable and continuous circulation process.

[0024] Example 1: The following describes the specific implementation of the present invention in detail with reference to the system structure and process.

[0025] Equipment Connection and Deployment: Tank AZ-12106A and Tank BZ-12106B are arranged in parallel. Tank AZ-12106A is connected to the inlet of waste acid direct delivery pump AP-12107A via pipeline No. 1, and Tank BZ-12106B is connected to the inlet of waste acid direct delivery pump BP-12107B via pipeline No. 2. Pipeline No. 4 is connected between pipeline No. 1 and pipeline No. 2. The outlets of waste acid direct delivery pumps AP-12107A and BP-12107B are connected to pipeline No. 3. Pipeline SP-12107S, which is connected to pipeline No. 4, is connected to pipeline No. 3. Pipelines to incinerator A and incinerator B are connected to pipeline No. 3 to complete the connection between the waste acid direct delivery unit and the incinerator. Circulation unit configuration: Waste acid circulation pump AP-12106A is connected to tank AZ-12106A via pipeline to form a closed circulation loop; waste acid circulation pump BP-12106B is connected to tank BZ-12106B via pipeline to form a closed circulation loop; pipeline No. 6 is connected between the inlet pipelines of waste acid circulation pumps AP-12106A and BP-12106A, and pipeline No. 7 is connected between the outlet pipelines; pipeline SP-12106S connected between pipelines No. 6 and No. 7; a return tank regulating valve AV-21 and a check valve are installed on the outlet pipeline of waste acid circulation pump AP-12106A, and a return tank regulating valve BV-22 and a check valve are installed on the outlet pipeline of waste acid circulation pump BP-12106B.

[0026] Operation process: Start the waste acid circulation unit and put waste acid circulation pumps AP-12106A and BP-12106B into operation, while waste acid circulation pump SP-12106S is on standby as a backup pump; adjust the circulation flow rate through return tank regulating valves AV-21 and BV-22 respectively, and precisely control the circulation volume in tanks AZ-12106A and BZ-12106B at 130t / h. The circulating shear force can be used to break the asphaltene in the waste acid into tiny particles, thereby achieving homogenization treatment of waste acid.

[0027] Waste acid direct delivery process: Start the waste acid direct delivery unit, and select either waste acid direct delivery pump AP-12107A or waste acid direct delivery pump BP-12107B to be put into operation according to the delivery requirements. Waste acid direct delivery pump SP-12107S is in standby mode. The homogenized waste acid in tanks AZ-12106A and BZ-12106B enters the corresponding waste acid direct delivery pumps through pipeline No. 1 and pipeline No. 2, respectively, and is then delivered to incinerator A and incinerator B for incineration through pipeline No. 3. Flow monitoring instruments on pipelines No. 1, No. 2, No. 3, and the pipeline with waste acid direct delivery pump SP-12107S monitor the flow rate in real time to ensure stable delivery.

[0028] Emergency switching operation: When the waste acid direct delivery pump AP-12107A fails, immediately close its inlet and outlet valves, start the waste acid direct delivery pump SP-12107S, and extract waste acid from tank AZ-12106A or tank BZ-12106B through pipeline No. 4. The waste acid is then transported to pipeline No. 3 through the pipeline connected to the waste acid direct delivery pump SP-12107S to ensure a continuous supply of waste acid. When the waste acid circulation pump AP-12106A fails, close its inlet and outlet valves, start the waste acid circulation pump SP-12106S, and connect it to the circulation loop of tank AZ-12106A through pipelines No. 6 and No. 7 to maintain the homogeneous circulation of waste acid in tank AZ-12106A. The same method can be used to handle the failure of waste acid circulation pump BP-12106B.

[0029] Routine maintenance: Regularly check the operating status of each pump, the sealing of pipelines, and the accuracy of flow monitoring instruments; check the adjustment accuracy of return tank regulating valves AV-21 and BV-22 to ensure that the circulation volume is maintained in the range of 130-150t / h; regularly check the condition of the corrosion-resistant coating on the inner wall of tanks AZ-12106A and BZ-12106B, and maintain or replace it in a timely manner to ensure the service life of the equipment.

[0030] Finally, it should be noted that the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A waste acid direct delivery system for a chemical plant, comprising a sulfuric acid plant incinerator, characterized in that, The system includes a waste acid direct delivery unit with a waste acid recycling unit, which is connected to the sulfuric acid plant incinerator to achieve directional delivery and incineration of waste acid. The waste acid direct delivery unit includes tanks A (Z-12106A) and B (Z-12106B) connected in parallel. Tanks A (Z-12106A) and B (Z-12106B) are respectively connected to waste acid direct delivery pump A (P-1) via pipeline No. 1 and pipeline No.

2. 2107A) and waste acid direct delivery pump B (P-12107B), the outlets of the waste acid direct delivery pump A (P-12107A) and waste acid direct delivery pump B (P-12107B) are connected to pipeline No. 3, pipeline No. 4 is connected between pipeline No. 1 and pipeline No. 2, and pipeline No. 3 and pipeline No. 4 are connected to a pipeline with waste acid direct delivery pump S (P-12107S), and the sulfuric acid unit incinerator is connected to pipeline No.

3.

2. The waste acid direct delivery system for a chemical plant according to claim 1, characterized in that, The waste acid circulation unit includes waste acid circulation pump A (P-12106A), waste acid circulation pump B (P-12106B), and waste acid circulation pump S (P-12106S). Waste acid circulation pump A (P-12106A) is connected to tank A (Z-12106A) via pipeline to form a circulation loop. Waste acid circulation pump B (P-12106B) is connected to tank B (Z-12106S) via pipeline. B) A circulation loop is formed on the pipeline. Pipeline No. 6 is connected between the pipelines at the inlet ends of waste acid circulation pump A (P-12106A) and waste acid circulation pump B (P-12106B). Pipeline No. 7 is connected between the pipelines at the outlet ends of waste acid circulation pump A (P-12106A) and waste acid circulation pump B (P-12106B). Pipeline No. 6 and pipeline No. 7 are connected to a pipeline with waste acid circulation pump S (P-12106S).

3. The waste acid direct delivery system for a chemical plant according to claim 2, characterized in that, The outlet pipeline of the waste acid circulation pump A (P-12106A) is connected to a return tank regulating valve A (V-21), and the outlet pipeline of the waste acid circulation pump B (P-12106B) is connected to a return tank regulating valve B (V-22). The return tank regulating valve A (V-21) and the return tank regulating valve B (V-22) can control the circulation volume at 130-150t / h.

4. A waste acid direct delivery system for a chemical plant according to claim 1, characterized in that, The sulfuric acid plant incinerator includes incinerator A and incinerator B. Incinerator A and incinerator B are respectively connected to pipeline No. 3 through pipelines to realize the corresponding connection between the waste acid direct delivery unit and the incinerator.

5. The waste acid direct delivery system for a chemical plant according to claim 1, characterized in that, The waste acid direct delivery pump S (P-12107S) can be switched to be used when the waste acid direct delivery pump A (P-12107A) or the waste acid direct delivery pump B (P-12107B) fails, so as to ensure continuous connection between the waste acid direct delivery unit and the incinerator.

6. The waste acid direct delivery system for a chemical plant according to claim 3, characterized in that, Check valves are connected to the pipeline at the outlet end of waste acid circulation pump A (P-12106A) and the pipeline at the outlet end of waste acid circulation pump B (P-12106B) to prevent waste acid from flowing back.

7. The waste acid direct delivery system for a chemical plant according to claim 1, characterized in that, The No. 1, No. 2, No. 3 pipelines and the pipeline with the waste acid direct delivery pump S (P-12107S) are each equipped with flow monitoring instruments to monitor the flow rate of waste acid from the waste acid direct delivery unit to the incinerator in real time.

8. The waste acid direct delivery system for a chemical plant according to claim 1, characterized in that, The waste acid direct delivery unit can form a 1-on, 2-standby operation state among waste acid direct delivery pump A (P-12107A), waste acid direct delivery pump B (P-12107B), and waste acid direct delivery pump S (P-12107S).

9. A waste acid direct delivery system for a chemical plant according to claim 3, characterized in that, The waste acid circulation unit can form a 2-on-1-standby operation state among waste acid circulation pump A (P-12106A), waste acid circulation pump B (P-12106B), and waste acid circulation pump S (P-12106S).

10. A waste acid direct delivery system for a chemical plant according to claim 1, characterized in that, The inner walls of tank A (Z-12106A) and tank B (Z-12106B) are provided with a corrosion-resistant coating.

Images