Water feeding control system for alkali washing tank of continuous reforming regeneration unit

Abstract

The utility model belongs to the field of chemical engineering, and particularly relates to a continuous reforming regeneration unit alkali wash tank water feeding control system which comprises an alkali wash tank, a turbine water pipe network is connected to an inlet of the alkali wash tank through a water feeding pipeline, and the water feeding pipeline is provided with a water injection pump; a tank bottom outlet of the alkali washing tank is sequentially connected with an alkali liquor circulating pump, a static mixer and a regenerated gas water cooler through a backflow pipeline, an outlet of the backflow pipeline is connected into the alkali washing tank, an outlet of the water injection pump is connected to the backflow pipeline through a crossing pipeline, and a flow control valve is arranged on the crossing pipeline. According to the water feeding control system for the alkali washing tank, the effect of neutralizing acid gas by alkali liquor is better, the total salt content in liquid discharged from the bottom is greatly reduced, the corrosion period of the acid gas caused by poor alkali washing is delayed, and the positive effect on improving the safe operation of the device is achieved. The frequent tube bundle replacement cost is saved; the consumption of a liquid caustic soda dissolving agent is reduced, and the influence of equipment corrosion on the operation of the device is also reduced.

Description

Technical Field

[0001] The utility model belongs to the field of chemical industry, and in particular relates to a water supply control system for an alkali washing tank of a continuous reforming regeneration unit. Background Art

[0002] The main purpose of the caustic washing system of the catalyst regeneration unit of the continuous reforming unit is to neutralize the acidic gases such as chlorine and CO2 in the regeneration cycle gas through low-concentration NaOH caustic solution to prevent the acidic gases from corroding the downstream equipment and pipelines. The existing process requires continuous water injection and discharge of salt-containing wastewater to maintain the pH value in the caustic washing tank at a weak alkaline environment of 7.5-8.5. However, due to the pressure fluctuation of the turbine water network, the outlet flow of the water injection pump is unstable, resulting in the fluctuation of the water injection volume with the pressure fluctuation of the turbine water network, which in turn causes the pH value of the caustic solution to fluctuate.

[0003] When the water injection volume decreases, the pH value rises, which will cause the regeneration gas to quickly form salt and clog the mixer at the inlet of the alkali washing tank. The regeneration gas and alkali solution are not mixed evenly, causing the acidic gas to corrode the downstream heat exchanger tube bundle, the internal components of the alkali washing tank and the downstream drying system.

[0004] When the water injection volume increases, the pH value decreases, and the amount of alkali solution in the alkali cleaning tank is insufficient, which will also cause acidic gases to corrode the downstream heat exchanger tube bundle, the internal components of the alkali cleaning tank, and the downstream drying system.

[0005] According to a large amount of operating data, the heat exchanger tube bundles of the alkaline cleaning system cannot be used and are replaced once a year on average due to increased corrosion and leakage, and the replacement frequency is relatively high.

[0006] In summary, the alkali washing system in the prior art has the following disadvantages: ① The water injection volume of the alkali washing system is greatly affected by the pressure fluctuation of the turbine water network, and the flow rate is unstable, resulting in large fluctuations in the pH value of the alkali washing solution, frequent corrosion and leakage of the heat exchanger tube bundle of the alkali washing system, serious corrosion of other pipelines and equipment in the alkali washing system, and frequent corrosion and internal leakage of valves; ② The alkali washing effect of the regenerated gas is not good, resulting in a high pressure difference at the static mixer at the inlet of the alkali washing tank, increased alkali solution consumption, incomplete alkali washing of the regenerated acidic gas, and corrosion of the rear system caused by entering the rear system, which has a great impact on the safe production of the device. Summary of the invention

[0007] In view of the defects of the prior art mentioned above, the purpose of the utility model is to provide a water supply control system for the alkali washing tank of a continuous reforming regeneration unit, which can realize automatic adjustment of the pH value and reduce corrosion to the downstream pipeline.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a water supply control system for an alkali washing tank of a continuous reforming regeneration unit, including an alkali washing tank, a turbine water pipe network connected to the inlet of the alkali washing tank through a water supply pipeline, and the water supply pipeline is provided with a water injection pump; the tank bottom outlet of the alkali washing tank is connected to an alkali liquid circulation pump, a static mixer and a regeneration gas water cooler in sequence through a reflux pipeline, the reflux pipeline outlet is connected back to the alkali washing tank, the water injection pump outlet is connected to the reflux pipeline through a crossing pipeline, and a flow control valve is provided on the crossing pipeline.

[0009] Furthermore, a pH online analyzer is arranged at the outlet of the alkali washing tank, and the pH online analyzer is connected to the flow control valve via a signal and controls the opening of the flow control valve.

[0010] Furthermore, the pH value of the pH online analyzer is set to 7.6±0.1.

[0011] Furthermore, the flow control valve is provided with a secondary line and a secondary line valve is installed.

[0012] Furthermore, the flow control valve is provided with front and rear gate valves to form a three-valve group.

[0013] Furthermore, a drain is provided on the rear path of the flow control valve.

[0014] Furthermore, the outlet of the crossover pipeline is connected to the inlet pipe section of the alkali solution circulation pump.

[0015] Furthermore, the reflux pipeline is connected to an alkali injection pipeline, and the alkali tank is connected to the inlet pipe section of the alkali solution circulation pump through the alkali injection pipeline and the alkali injection pump.

[0016] Furthermore, the tank top outlet of the alkali washing tank is connected to the drying system through a gas outlet pipeline, and the drying system outlet is connected to the regenerator.

[0017] Furthermore, the regeneration cycle gas from the regenerator is connected to the inlet of the static mixer, and a pressure difference gauge is arranged between the inlet and outlet of the static mixer.

[0018] Furthermore, circulating water flows through the shell side of the regeneration gas water cooler, and regeneration gas flows through the tube side of the regeneration gas water cooler.

[0019] The beneficial effects of the utility model are as follows: the alkali solution of the alkali washing tank water supply control system of the utility model has a better effect on neutralizing acidic gas, and the total salt content in the bottom discharge liquid is greatly reduced, delaying the corrosion cycle of acidic gas caused by poor alkali washing, which has a positive effect on improving the safe operation of the device. It saves the cost of frequent tube bundle replacement; saves the consumption of liquid alkali chemical, and also reduces the impact of equipment corrosion on the operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is the process flow of the water supply control system for the alkali washing tank of the utility model;

[0021] In the figure: 1, alkali washing tank, 2, water supply pipeline, 3, water injection pump, 4, reflux pipeline, 5, alkali liquid circulation pump, 6, static mixer, 7, regeneration gas water cooler, 8, crossing pipeline, 9, flow control valve, 10, PH online analyzer, 11, alkali injection pipeline, 12, alkali tank, 13, alkali injection pump, 14, gas outlet pipeline, 15, drying system, 16, differential pressure gauge;

[0022] A. Turbine water pipeline network, B. Regenerator, C. Regeneration circulating gas (acid gas) from the regenerator. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0024] See attached Figure 1 , a continuous reforming regeneration unit alkali washing tank water supply control system, including an alkali washing tank 1, a turbine water pipe network is connected to the inlet of the alkali washing tank 1 through a water supply pipeline 2, and the water supply pipeline 2 is provided with a water injection pump 3; the tank bottom outlet of the alkali washing tank 1 is connected to an alkali liquid circulation pump 5, a static mixer 6 and a regeneration gas water cooler 7 in sequence through a reflux pipeline 4, and the outlet of the reflux pipeline 4 is connected back to the alkali washing tank 1, and the outlet of the water injection pump 3 is connected to the reflux pipeline 4 through a crossover pipeline 8, and the outlet of the crossover pipeline 8 is connected to the inlet pipe section of the alkali liquid circulation pump 5, and the crossover pipeline 8 is provided with a flow control valve 9. A PH online analyzer 10 is provided at the outlet of the alkali washing tank, and the PH online analyzer 10 is connected to the flow control valve 9 through a signal and controls the opening of the flow control valve 9. The reflux pipeline 4 is connected to an alkali injection pipeline 11, and the alkali tank 12 is connected to the inlet pipe section of the alkali liquid circulation pump 5 through the alkali injection pipeline 11 and the alkali injection pump 13.

[0025] Based on the above technical solution, the flow control valve 9 and the pH value online analyzer 10 are automatically controlled; the pH value is set to 7.6±0.1, and is automatically controlled with the control valve, and the water injection volume is adjusted in time according to the pH value change to ensure the stability of the pH value.

[0026] In this embodiment, the flow control valve 9 is provided with front and rear gate valves to form a three-valve group. The flow control valve 9 is provided with a secondary line and a secondary line valve is installed. The rear path of the flow control valve is provided with a drain.

[0027] Based on the above technical solution, in order to prevent freezing and condensation in winter, the flow control valve needs to be insulated, and for the maintenance of the flow control valve, a secondary line valve is added, and a shower guide is added for drainage.

[0028] Furthermore, the tank top outlet of the alkali cleaning tank 1 is connected to the drying system 15 through the gas outlet pipeline 14, and the outlet of the drying system 15 is connected to the regenerator. The regeneration circulating gas from the regenerator is connected to the inlet of the static mixer 6, and a pressure difference meter 16 is arranged between the inlet and the outlet of the static mixer 6. The shell side of the regeneration gas water cooler circulates circulating water, and the tube side of the regeneration gas water cooler circulates regeneration gas.

[0029] After the modification and implementation of the water supply control system of the alkali washing tank of the utility model, it is safer, more reliable, and more energy-saving than the original design, and the safety of the device is improved. Specifically as follows: ①, the PH value is automatically adjusted, and the PH value can be stabilized at 7.6±0.1. ②, through a large amount of data exploration, when the PH value is controlled between 7.5-7.7, the mixing effect of the static mixer at the entrance of the alkali washing tank is the best, and the average pressure difference of the mixer is maintained at 30KPA, which is much lower than the previous 60-80KPA; ③, the present invention has a better effect on neutralizing acidic gases with alkali liquid after the improvement, and the total salt content in the bottom discharge liquid is greatly reduced, from about 3%wt before the modification to about 1% at present, which greatly delays the corrosion cycle of acidic gases caused by poor alkali washing. After the improvement, the heat exchanger tube bundle of the alkali washing system has not had corrosion and leakage problems for 4 consecutive years, which has a positive effect on improving the safe operation of the device. ④, saves the cost of frequent tube bundle replacement; ⑤, saves the consumption of liquid alkali chemical, and also reduces the impact of equipment corrosion on the operation of the device.

[0030] The present invention does not disclose some common knowledge in the art.

[0031] The above examples are only the best embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. The water supply control system of the caustic washing tank of the continuous reforming regeneration unit is characterized by: It includes an alkali washing tank, the turbine water network is connected to the inlet of the alkali washing tank through a water supply pipeline, and the water supply pipeline is provided with a water injection pump; the tank bottom outlet of the alkali washing tank is connected to an alkali liquid circulation pump, a static mixer and a regeneration gas water cooler in sequence through a reflux pipeline, the reflux pipeline outlet is connected back to the alkali washing tank, the water injection pump outlet is connected to the reflux pipeline through a crossing pipeline, and the crossing pipeline is provided with a flow control valve.

2. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1 is characterized in that: A PH online analyzer is arranged at the outlet of the alkali washing tank, and the PH online analyzer is connected with the flow control valve through a signal and controls the opening of the flow control valve.

3. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1 is characterized in that: The flow control valve is provided with a secondary line and is equipped with a secondary line valve.

4. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1, characterized in that: The flow control valve is provided with front and rear gate valves to form a three-valve group.

5. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1, characterized in that: The rear path of the flow control valve is provided with a shower guide.

6. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1, characterized in that: The outlet of the crossing pipeline is connected to the inlet pipe section of the alkali solution circulation pump.

7. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1, characterized in that: The reflux pipeline is connected with an alkali injection pipeline, and the alkali tank is connected to the inlet pipe section of the alkali solution circulation pump through the alkali injection pipeline and the alkali injection pump.

8. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 1, characterized in that: The tank top outlet of the alkali cleaning tank is connected to the drying system through a gas outlet pipeline, and the outlet of the drying system is connected to the regenerator.

9. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 8, characterized in that: The regeneration cycle gas from the regenerator is connected to the inlet of the static mixer, and a pressure difference gauge is set between the inlet and outlet of the static mixer.

10. The continuous reforming regeneration unit alkaline washing tank water supply control system according to claim 9, characterized in that: Circulating water flows through the shell side of the regeneration gas water cooler, and regeneration gas flows through the tube side of the regeneration gas water cooler.

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