System for regulating and controlling alkalinity of PO product

Abstract

The invention discloses a PO product alkalinity regulation and control system, which belongs to the field of chemical production, and comprises a desalted water pipeline connected with a sulfuric acid preparation tank, the sulfuric acid preparation tank, a sulfuric acid delivery pump, a mixer II, a flash tank, a feed pump, a PO separation tower and a buffer tank connected, the bottom end of the mixer I is communicated with a pipeline between the sulfuric acid delivery pump and the mixer II, sulfuric acid is mixed through the mixer I when being injected, a sulfuric acid pipeline is connected with the mixer I, a circulating material pipeline is communicated with the mixer II and is mixed with a dilute sulfuric acid material of the sulfuric acid delivery pump, and a crude PO material at the top of the PO separation tower is connected through an output pipeline; the problems that the alkalinity of the epoxypropane product is high and the quality of the product is affected due to the fact that an existing device does not have effective measures to control the alkalinity of the epoxypropane product are solved, and the device is mainly applied to the aspect of PO product alkalinity regulation and control.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, and in particular relates to a system for regulating the alkalinity of a PO product. Background Art

[0002] While the chlorohydrin process and co-oxidation process were once widely used, they still suffer from numerous shortcomings, such as the high investment required to manage wastewater and waste residues generated by the chlorohydrin process and the inability to handle the byproducts of the co-oxidation process. Consequently, the development of green, simple processes with minimal pollution and byproducts has become a key focus. Direct propylene oxidation, however, addresses these challenges and offers numerous unique advantages, making it a hot topic for research and development by companies both domestically and internationally in recent years. Direct propylene epoxidation to propylene oxide (HPPO), a new process offering simplicity, few byproducts, and high added value, is currently being widely promoted.

[0003] High propylene oxide alkalinity can reduce the yield of downstream products and cause catalyst poisoning. Consequently, downstream requirements for the alkalinity of propylene oxide products have become increasingly stringent. Therefore, measures need to be taken to control the alkalinity of propylene oxide products to improve product quality and enhance economic benefits.

[0004] Application No. 201310502569.3 discloses a method for reducing the alkalinity of a propylene oxide product. This method involves connecting a nitrogen charging device to the reboiler outlet pipe or feed pipe of a distillation column. When the alkalinity of the propylene oxide product is high, a manual valve is opened to charge nitrogen. While this method is simple to operate, it only allows intermittent control and cannot stably control the product alkalinity. Furthermore, the introduction of nitrogen into the system affects the pressure of the distillation column, causing pressure fluctuations and impacting operation.

[0005] At present, the HPPO process mostly adopts the Evonik / Wood process. According to the Journal of Jilin Institute of Chemical Technology: 1007-2853(2018)05-0009-05, in the Evonik / Wood HPPO process propylene oxide separation system, propylene oxide first enters the propylene oxide pre-separation system, and the crude propylene oxide in the propylene oxide pre-separation system then enters the propylene oxide refining tower for purification. The propylene oxide product is produced at the top of the tower, and the methanol-water solution in the bottom of the tower and the methanol-water in the bottom of the pre-separation system are easily merged and discharged to the methanol unit together.

[0006] Currently, existing devices do not have effective measures to control the alkalinity of propylene oxide products, resulting in high alkalinity of propylene oxide products, which affects the quality of the product. Summary of the Invention

[0007] Purpose of the invention: In response to the shortcomings of the existing technology, the present invention provides a system for controlling the alkalinity of PO products, which solves the problem that the existing devices have no effective measures to control the alkalinity of propylene oxide products, resulting in high alkalinity of propylene oxide products and affecting product quality.

[0008] The invention discloses a system for regulating the alkalinity of a PO product, comprising a desalted water pipeline, a sulfuric acid preparation tank, a sulfuric acid pipeline, a sulfuric acid delivery pump, a first mixer, a second mixer, a flash tank, a PO separation tower feed pump, a PO separation tower and a buffer tank. The system is characterized in that the desalted water pipeline is connected to the sulfuric acid preparation tank, the sulfuric acid preparation tank, the sulfuric acid delivery pump, the second mixer, the flash tank, the feed pump, the PO separation tower and the buffer tank are connected, one end extending from the top of the first mixer is connected to the sulfuric acid preparation tank, the bottom end of the first mixer is connected to a pipeline between the sulfuric acid delivery pump and the second mixer, sulfuric acid is mixed through the first mixer when injected, the sulfuric acid pipeline is connected to the first mixer, a circulating material pipeline is connected to the second mixer and mixed with dilute sulfuric acid material from the sulfuric acid delivery pump, and crude PO material at the top of the PO separation tower is delivered through an output pipeline.

[0009] Preferably, a sampler, a first level gauge and a second thermometer are provided on the sulfuric acid configuration tank, and after configuration is completed, the sampler performs sulfuric acid concentration analysis.

[0010] Preferably, a flow meter and a regulating valve are provided on the pipeline between the sulfuric acid delivery pump and the second mixer.

[0011] Preferably, an analyzer is provided on the flash tank to monitor the pH of the material.

[0012] Preferably, a thermometer is provided on a pipe extending from one end of the top of the mixer to the sulfuric acid preparation tank.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] The beneficial effects of the present invention are:

[0015] The beneficial effects of the present invention are as follows: compared with the existing process, the present invention provides a method for regulating the alkalinity of PO products, adds sulfuric acid configuration facilities, and regulates the pH of the material by adding dilute sulfuric acid to the circulating material, thereby controlling the alkalinity of the PO product, improving the quality of the PO product, and improving the quality and efficiency of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of the present invention.

[0017] In the figure: 1. Desalted water pipeline; 2. Sulfuric acid preparation tank; 3. Sampler; 4. Thermometer 1; 5. Liquid level gauge 1; 6. Thermometer 2; 7. Mixer 1; 8. Sulfuric acid pipeline; 9. Sulfuric acid delivery pump; 10. Flow meter; 11. Control valve; 12. Mixer 2; 13. Circulating material pipeline; 14. Analyzer; 15. Flash tank; 16. PO separation tower feed pump; 17. PO separation tower; 18. Buffer tank; 19. Output pipeline. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0019] In one embodiment, a system for controlling the alkalinity of a PO product includes a desalted water pipeline 1, a sulfuric acid preparation tank 2, a sulfuric acid pipeline 8, a sulfuric acid delivery pump 9, a mixer 7, a mixer 2 12, a flash tank 15, a PO separation tower 17, a feed pump 16, a PO separation tower 17 and a buffer tank 18. The desalted water pipeline 1 is connected to the sulfuric acid preparation tank 2, the sulfuric acid preparation tank 2, the sulfuric acid delivery pump 9, the mixer 2 12, the flash tank 15, the feed pump 16, the PO separation tower 17 and the buffer tank 18 are connected. One end extending from the top of the mixer 7 is connected to the sulfuric acid preparation tank 2, the bottom end of the mixer 7 is connected to the pipeline between the sulfuric acid delivery pump 9 and the mixer 2 12, the sulfuric acid pipeline 8 is connected to the mixer 7, the circulating material pipeline 13 is connected to the mixer 2 12, and the crude PO material at the top of the PO separation tower 17 is transported through the output pipeline 19.

[0020] In one embodiment, a sampler 3 , a liquid level gauge 5 , and a thermometer 6 are provided on the sulfuric acid preparation tank 2 .

[0021] In one embodiment, a flow meter 10 and a regulating valve 11 are provided in the pipeline between the sulfuric acid delivery pump 9 and the second mixer 12 .

[0022] In one embodiment, an analyzer 14 is provided on the flash tank 15 .

[0023] In one embodiment, a thermometer 4 is provided on a pipe extending from one end of the top of the mixer 7 to the sulfuric acid preparation tank 2 .

[0024] The above method for regulating the alkalinity of the P0 product works as follows:

[0025] Desalted water is first delivered to sulfuric acid preparation tank 2 via desalted water pipeline 1. When the liquid level in the sulfuric acid preparation tank reaches 50-70%, level gauge 1 (5) monitors the level. Sulfuric acid delivery pump 9 is activated to circulate the solution. Sulfuric acid is then injected into mixer 7 via sulfuric acid pipeline 8. During injection, thermometers 1 (4) and 2 (6) are monitored to monitor and control the temperature below 50°C. If the temperature rises rapidly, the injection rate is reduced or even halted. After sulfuric acid preparation is complete, the concentration is analyzed using sampler 3 and maintained at 3-8 wt%.

[0026] Dilute sulfuric acid is injected into the mixer 2 12 to mix with the circulating material and then enters the flash tank 15. The pH of the material in the flash tank 15 is monitored in real time by the online analyzer 14 and the pH value is controlled at 4-6. The amount of dilute sulfuric acid is adjusted by the flow meter 10 to adjust the pH value of the material in the flash tank 15.

[0027] The material in the flash tank 15 is transported to the PO separation tower 17 for PO purification through the PO separation tower transfer pump 16. The crude PO material at the top of the PO separation tower 17 is transported to the downstream through the output pipeline 19 for further analysis; the material in the bottom of the PO separation tower 17 is transported to the buffer tank 18 and then sent to the downstream for processing.

[0028] This method is used to adjust the pH of the material by adding dilute sulfuric acid to the circulating material, thereby controlling the alkalinity of the PO product, improving the quality of the PO product, and enhancing the quality and efficiency of the enterprise.

Claims

1. A system for controlling the alkalinity of a PO product, comprising a desalted water pipeline (1), a sulfuric acid preparation tank (2), a sulfuric acid pipeline (8), a sulfuric acid delivery pump (9), a mixer (7), a mixer (12), a flash tank (15), a PO separation tower (17), a feed pump (16), a PO separation tower (17) and a buffer tank (18), characterized in that: The desalted water pipeline (1) is connected to the sulfuric acid preparation tank (2); The sulfuric acid preparation tank (2), the sulfuric acid delivery pump (9), the second mixer (12), the flash tank (15), the feed pump (16), the PO separation tower (17) and the buffer tank (18) are connected; One end of the top of the mixer (7) is connected to the sulfuric acid preparation tank (2), and the bottom of the mixer (7) is connected to the pipeline between the sulfuric acid delivery pump (9) and the mixer (12); The sulfuric acid pipeline (8) is connected to the mixer (7); The circulating material pipeline (13) is connected to the second mixer (12); The crude PO material at the top of the PO separation tower (17) is transported through the output pipeline (19).

2. A system for controlling the alkalinity of a PO product according to claim 1, characterized in that: A sampler (3), a first level gauge (5) and a second thermometer (6) are provided on the sulfuric acid preparation tank (2).

3. A system for controlling the alkalinity of a PO product according to claim 1, characterized in that: The pipeline between the sulfuric acid delivery pump (9) and the second mixer (12) is provided with a flow meter (10) and a regulating valve (11).

4. A system for controlling the alkalinity of a PO product according to claim 1, characterized in that: An analyzer (14) is provided on the flash tank (15).

5. The system for controlling the alkalinity of a PO product according to claim 1, characterized in that: A thermometer (4) is provided on a pipe extending from one end of the top of the mixer (7) to the sulfuric acid preparation tank (2).

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