Control system for inhibiting heteroalcohol acid corrosion in methanol preparation process

Abstract

The utility model discloses a control system for inhibiting heteroalcohol acid corrosion in a methanol preparation process. The control system comprises a lye tank, a lye valve, a lye pump, a fusel valve, a feed valve, a fusel storage tank, a discharge valve, a pH meter I, a pH meter II, a pH meter III, a pH meter IV, a PLC (Programmable Logic Controller), a frequency converter, a fusel pipe, a feed pipe and a discharge pipe, wherein the lye valve is positioned on a pipeline for connecting the lye pump and the lye tank; the feeding pipe is connected with the fusel storage tank, and the lower part of the fusel storage tank is connected with the discharging pipe; a pH meter II is arranged on the feeding pipe, a pH meter I is arranged on the discharging pipe, a pH meter III is arranged in the middle of the fusel storage tank, a pH meter IV is arranged at the bottom of the fusel storage tank, the PLC is connected with the alkali liquor pump through a frequency converter, and the PLC is connected with the pH meter I, the pH meter II, the pH meter III and the pH meter IV through signal lines. According to the fusel pH value adjusting device, the fusel pH value can be quickly, effectively and automatically adjusted, and the problems that in the existing fusel pH value adjusting process, the process is tedious, pH value measurement is inaccurate, and the pH value adjusting effect is poor are solved.

Description

Technical Field

[0001] The utility model relates to the field of processing fusel alcohols produced in a methanol preparation process, in particular to a control system for inhibiting fusel alcohol acid corrosion in a methanol preparation process. Background Art

[0002] Fusel alcohols are produced during the methanol production process. After concentration, they participate in the distillation process. Fusel alcohols are weakly acidic media and include high-boiling-point substances such as 2-methyl-3-pentanol, 3-hexanol, 2-methyl-1-pentanol, 5-methyl-3-hexanol, and 2-heptanol. These high-boiling-point substances are poorly or slightly soluble in water. At high temperatures, they decompose to produce acidic substances, which can cause severe corrosion to methanol production equipment.

[0003] Adding lye to fusel alcohol combines with the acidic substances in the alcohol to form corresponding salts and water. This not only balances the pH of the fusel alcohol, reducing corrosion to pipes and equipment, but also reduces impurities generated during methanol production. Currently, the production process requires hourly pH measurements of the fusel alcohol using pH test paper, and manual adjustment of the lye pump flow rate based on the test results. This testing process is entirely manual, resulting in a cumbersome and inefficient workflow. Because the pH test paper measurements are significantly influenced by subjective factors, objective and accurate lye flow rate adjustment is impossible. Furthermore, the one-hour interval between measurements, the long fusel alcohol pipelines, and the large fusel alcohol storage tanks lead to a certain lag in the pH adjustment process, resulting in poor regulation effectiveness. Utility Model Content

[0004] In order to solve the problems of complicated process, inaccurate pH value measurement and poor pH value adjustment effect in the process of adjusting the pH value of fusel alcohol, the utility model provides a control system for inhibiting fusel alcohol corrosion in the methanol preparation process. The control system can measure the pH value of fusel alcohol in the fusel alcohol storage tank and pipeline in real time, and adopts fuzzy PID control algorithm to control the alkali solution pump, adjust the required alkali solution dosage, and realize automatic adjustment of the pH value of fusel alcohol.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a control system for inhibiting fusel acid corrosion in a methanol preparation process, comprising an alkali solution tank 1, an alkali solution valve 2, an alkali solution pump 3, a fusel alcohol valve 4, a feed valve 5, a fusel alcohol storage tank 6, a discharge valve 7, a pH meter I 8, a pH meter II 9, a pH meter III 10, a pH meter IV 11, a PLC controller 12, a frequency converter 13, a fusel alcohol pipe 14, a feed pipe 15, and a discharge pipe 16.

[0006] The alkali solution valve 2 is located on the pipeline connecting the alkali solution pump 3 and the alkali solution tank 1 , the fusel alcohol valve 4 is located on the fusel alcohol pipe 14 , and the feed valve 5 is located on the feed pipe 15 .

[0007] The feed pipe 15 is connected to the fusel alcohol storage tank 6 , and the feed pipe 15 is located at the top of the fusel alcohol storage tank 6 . The lower part of the fusel alcohol storage tank 6 is connected to the discharge pipe 16 , and the discharge valve 7 is located on the discharge pipe 16 .

[0008] The feed pipe 15 is provided with a pH meter II 9, the discharge pipe 16 is provided with a pH meter I8, the middle of the fusel alcohol storage tank 6 is provided with a pH meter III 10, and the bottom of the fusel alcohol storage tank 6 is provided with a pH meter IV 11. The PLC controller 12 is connected to the alkali liquid pump 3 through the frequency converter 13, and the PLC controller 12 is respectively connected to the pH meter I8, pH meter II 9, pH meter III 10, and pH meter IV 11 through signal lines.

[0009] Furthermore, the alkali solution pump 3 is a diaphragm metering pump.

[0010] Furthermore, the PLC controller 12 is a programmable logic controller.

[0011] Furthermore, the PLC controller 12 controls the frequency converter 13 using a fuzzy PID control algorithm.

[0012] Furthermore, the lye valve 2, fusel alcohol valve 4, feed valve 5 and discharge valve 7 are electric and manual dual-purpose closed valves.

[0013] Compared with the existing methanol production process to inhibit the corrosion control system of alcohol acid, the utility model has the following advantages.

[0014] The utility model discloses a control system for inhibiting fusel acid corrosion in a methanol preparation process. Automatic control of the pH value of fusel alcohol can be achieved through a pH meter I 8, a pH meter II 9, a pH meter III 10, a pH meter IV 11, a PLC controller 12, and a frequency converter 13. There is no need for manual measurement of the pH value of fusel alcohol, manual adjustment of an alkali solution pump 3, and the like, thereby effectively simplifying the work process.

[0015] The utility model discloses a control system for inhibiting fusel alcohol corrosion in a methanol preparation process. The control system adopts multiple pH meters to measure the pH values ​​of a feed pipe 15, the middle of a fusel alcohol storage tank 6, the bottom of the fusel alcohol storage tank 6, and a discharge pipe 16. A weighted calculation is performed to obtain a weighted pH value of the fusel alcohol. A fuzzy PID control algorithm is used to comprehensively judge the amount of alkali solution based on the weighted pH value of the fusel alcohol, thereby achieving precise regulation of the pH value of the fusel alcohol and reducing fluctuations in the pH value of the fusel alcohol.

[0016] The utility model provides a control system for inhibiting fusel acid corrosion in a methanol preparation process. A frequency converter 13 is used to control an alkali solution pump 3. Compared with manually adjusting the range of the alkali solution pump 3, the control effect is higher in control accuracy, better in real time performance, and more energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is a system diagram of a control system for inhibiting fusel acid corrosion in a methanol preparation process according to the utility model. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be noted that the terms "top", "bottom", "one side", "the other side", "front", "back", "middle", "inside", "top", "bottom end", etc., indicating positions or positional relationships, are based on the positions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, unless otherwise expressly specified or limited, the terms "mounted", "connected", and "connected" should be understood in a broad sense, for example, they can mean fixed connection, detachable connection, or integral connection; they can mean mechanical connection or electrical connection; they can mean direct connection, indirect connection through an intermediate medium, or internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] The following is combined with Figure 1 , the technical solution of the utility model is described in detail.

[0021] The utility model provides a control system for inhibiting fusel acid corrosion in a methanol preparation process, comprising an alkali solution tank 1, an alkali solution valve 2, an alkali solution pump 3, a fusel alcohol valve 4, a feed valve 5, a fusel alcohol storage tank 6, a discharge valve 7, a pH meter I 8, a pH meter II 9, a pH meter III 10, a pH meter IV 11, a PLC controller 12, a frequency converter 13, a fusel alcohol pipe 14, a feed pipe 15, and a discharge pipe 16.

[0022] The alkali solution tank 1 is used to store alkali solution, which is a 5% concentration of sodium hydroxide solution in this embodiment. The upper end of the alkali solution tank 1 is connected to an alkali solution valve 2; the alkali solution pump 3 is a diaphragm metering pump that can adjust the flow rate and is used to transport the alkali solution. The alkali solution and the fusel alcohol in the fusel alcohol pipe 14 are mixed in the feed pipe 15 and then enter the fusel alcohol storage tank 6. The pH value of the mixed fusel alcohol ranges from 6.5 to 7, and the pH value is close to neutral.

[0023] The fusel alcohol storage tank 6 is used to maintain the flow rate and pH value of the fusel alcohol liquid in the discharge pipe 16; the fusel alcohol storage tank 6 is equipped with a pH meter III 10 and a pH meter IV 11, which are respectively used to online measure the pH values ​​of the middle and bottom of the fusel alcohol in the fusel alcohol storage tank; the feed pipe 15 is provided with a pH meter II 9, which is used to online measure the pH value of the alkali solution and fusel alcohol in the pipeline after mixing; the discharge pipe 16 is provided with a pH meter I 8, which is used to measure the pH value of the fusel alcohol entering the fusel alcohol concentration device.

[0024] The PLC controller 12 is electrically connected to the pH meter I8, pH meter II9, pH meter III10, and pH meter IV11, and transmits the measured pH value signal to the PLC controller 12 in real time; the PLC controller 12 is a Siemens S7-1214C model, equipped with a communication board, an analog input module and a touch screen, the communication board is used to support RS485 communication, the analog input module is used to receive the signal of the pH meter I8, pH meter II9, pH meter III10, and pH meter IV11, the touch screen is used to manually set the target value for adjusting the pH value of the fusel alcohol, and the PLC The controller 12 calculates the pH weighted value of the fusel alcohol as the input of the fuzzy PID control algorithm, and uses the fuzzy PID control algorithm to control the frequency converter 13; the frequency converter 13 is electrically connected to the PLC controller 12, and the communication method adopts RS485 communication. The PLC controller 12 adopts the SCL language to implement the fuzzy PID control algorithm. The PLC controller 12 adjusts the output frequency of the frequency converter 13 in real time according to the calculation results of the fuzzy PID control algorithm, and performs stepless speed regulation on the connected alkali liquid pump 3, thereby accurately controlling the alkali liquid flow rate and adjusting the pH value of the fusel alcohol.

[0025] The reason for adopting the above structure is that the pH value of the fusel alcohol needs to be dynamically adjusted in the subsequent purification process of the fusel alcohol, but the fusel alcohol conveying pipeline is long, and the adjustment of the pH value of the fusel alcohol has a certain hysteresis. In order to ensure that the pH value meets the requirements when the fusel alcohol is purified, multiple pH meters are set in the conveying pipeline and the fusel alcohol storage tank 6 for detection and weighted calculation. The weight calculation method is that pH meter I8 accounts for 50% of the weight, pH meter II 9 accounts for 20% of the weight, pH meter III 10 accounts for 15% of the weight, and pH meter IV 11 accounts for 15% of the weight. The calculated value is the weighted pH value of the fusel alcohol.

[0026] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0027] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A control system for inhibiting fusel acid corrosion in a methanol preparation process, comprising an alkali solution tank (1), an alkali solution valve (2), an alkali solution pump (3), a fusel alcohol valve (4), a feed valve (5), a fusel alcohol storage tank (6), a discharge valve (7), a pH meter I (8), a pH meter II (9), a pH meter III (10), a pH meter IV (11), a PLC controller (12), a frequency converter (13), a fusel alcohol pipe (14), a feed pipe (15), and a discharge pipe (16), wherein the control system comprises: The alkali solution valve (2) is located on the pipeline connecting the alkali solution pump (3) and the alkali solution tank (1); the fusel alcohol valve (4) is located on the fusel alcohol pipe (14); the feed valve (5) is located on the feed pipe (15); the feed pipe (15) is connected to the fusel alcohol storage tank (6); the feed pipe (15) is located at the top of the fusel alcohol storage tank (6); the lower part of the fusel alcohol storage tank (6) is connected to the discharge pipe (16); the discharge valve (7) is located on the discharge pipe (16); the feed pipe (15) is provided with A pH meter II (9) is provided, a pH meter I (8) is provided on the discharge pipe (16), a pH meter III (10) is provided in the middle of the fusel alcohol storage tank (6), a pH meter IV (11) is provided at the bottom of the fusel alcohol storage tank (6), the PLC controller (12) is connected to the alkali liquid pump (3) through a frequency converter (13), and the PLC controller (12) is connected to the pH meter I (8), pH meter II (9), pH meter III (10), and pH meter IV (11) respectively through signal lines.

2. The control system for inhibiting fusel acid corrosion in a methanol production process according to claim 1, characterized in that The PLC controller (12) is a programmable logic controller.

3. The control system for inhibiting fusel acid corrosion in a methanol production process according to claim 1, characterized in that The alkali solution pump (3) is a diaphragm metering pump.

4. The control system for inhibiting fusel acid corrosion in a methanol production process according to claim 1, characterized in that The PLC controller (12) uses a fuzzy PID control algorithm to control the frequency converter (13).

5. The control system for inhibiting fusel acid corrosion in a methanol production process according to claim 1, characterized in that The lye valve (2), fusel alcohol valve (4), feed valve (5), and discharge valve (7) are electric and manual dual-purpose closed valves.

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