A method for optimizing adjustment of a final cooling tower

Abstract

The application discloses a kind of final cooling tower optimization adjustment methods, by measuring T4 temperature to the current working condition of final cooling tower is evaluated, if meet evaluation condition final cooling tower normal operation, otherwise according to formula to the final cooling tower coal gas temperature T4 is optimized and adjusted. Can in production process to the final cooling tower coal gas temperature timely adjustment, ensure that the final cooling tower coal gas temperature is in the appearance of out of regulation, especially when high, according to the importance of each parameter that influences the final cooling tower coal gas temperature, quickly adjust the final cooling tower coal gas temperature to regulation range, overcome the adjustment hysteresis defect caused by only adjusting part parameter or artificial experience deficiency, or part parameter limit processing, and part parameter is still in the defect of low position operation, reach the purpose of quickly, accurately optimize the final cooling tower coal gas temperature.

Description

Technical Field

[0001] This invention relates to the field of coal gas refining technology in the coal coking process, specifically to an optimized adjustment method for the final cooling tower. Background Technology

[0002] One of the key stages in coal gas refining during coal coking is the benzene removal stage, from which benzene—a byproduct—is a crucial raw material for the chemical industry. The benzene removal stage includes final gas cooling, benzene washing, and further benzene removal. The absorption of benzene from coke oven gas by the washing oil requires a suitable absorption temperature to ensure maximum absorption efficiency while maintaining smooth production. One factor determining the suitable absorption temperature is the gas temperature. In the preceding benzene removal stage, the gas temperature is higher than the suitable absorption temperature of the benzene washing tower. To ensure good benzene washing results, the benzene removal stage first needs to lower the gas temperature; this process takes place in the final cooling tower. The control of the final cooling gas temperature is often semi-automatic, relying heavily on human experience and judgment. This often results in problems such as adjustment lag, insufficient scientific and systematic approach, and the easy neglect of non-routine indicators. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned technical problems by providing an optimized regulation method for the final cooling tower that enables timely and efficient adjustment of the gas temperature exiting the final cooling tower during the production process.

[0004] To achieve the above objectives, the present invention provides a method for optimizing and adjusting a final cooling tower, as follows:

[0005] 1) Evaluate the current operating condition of the final cooling tower by measuring the T4 temperature. If the evaluation conditions are met, the final cooling tower is operating normally; otherwise, proceed to step 2).

[0006] 2) Optimize and adjust the gas temperature T4 exiting the final cooling tower according to formula (1).

[0007] T4=m1×F1+m2×T1+m3×F2+m4×T2+m5×F3+m6×T3+m7×Z1+C (1)

[0008] Where m1, m2, ..., m6, m7 are the coefficients of formula (1), and C is the constant of formula (1); T4 is the temperature of the gas exiting the final cooling tower, F1 is the flow rate of the gas entering the tower, T1 is the temperature of the gas entering the tower, F2 is the flow rate of the upper circulating liquid, T2 is the temperature of the upper circulating liquid, F3 is the flow rate of the lower circulating liquid, T3 is the temperature of the lower circulating liquid, Z1 is the tower resistance entering the tower, m1, m2, ..., m6, m7 are the coefficients, and C is the constant; T4 is the target parameter, F1, T1 and Z1 are important parameters, and F2, T2, F3 and T3 are process adjustable parameters;

[0009] The specific optimization and adjustment process is as follows:

[0010] 21) Obtain the available data set closest to the adjustment time. The data set includes important parameters and adjustable parameters in the final cooling tower. There are ≥500 available data sets. The coefficients and constants in formula (1) are obtained by fitting the collected available data sets.

[0011] 22) Arrange the coefficients of F2, T2, F3 and T3 in descending order, and then adjust the process adjustable parameters corresponding to the first two coefficients until the adjusted process adjustable parameters are substituted into formula (1) and the calculated T4 satisfies 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature, then the adjustment is terminated.

[0012] Furthermore, the evaluation conditions in step 1) are as follows:

[0013] When 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature, the final cooling tower operates normally; otherwise, proceed to step 2) to optimize and adjust the gas temperature T4 exiting the final cooling tower.

[0014] Furthermore, in step 2), the temperature T2 of the upper circulating coolant is 10~34℃, the temperature T3 of the lower circulating coolant is 20~39℃, and the tower resistance Z1 of the final cooling tower is 0.5~2KPa.

[0015] When there are temperature fluctuations in the front-end process during maintenance and recovery, T1 is taken as 40~58℃; when there is a backup device in the front-end process connected to the final cooling tower, T1 is the value obtained by summing and averaging the values ​​in the range of 40~58℃.

[0016] Furthermore, in step 21), the data during the maintenance, shutdown, and debugging processes are unusable data.

[0017] Further, in step 22), the adjustment of the two process adjustable parameters is based on the average value of 10 sets of available data at the most recent time point of the current process adjustable parameter. If it is a flow parameter F2 or F3, the interval is 1% of the maximum flow rate. If it is a temperature parameter T2 or T3, the interval is 0.5℃. The adjustment is made in a direction that is favorable to T4 until the T4 calculated after substituting the adjusted process adjustable parameter into formula (1) satisfies 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature. Then the adjustment is terminated.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The final cooling tower optimization and adjustment method of the present invention can adjust the temperature of the gas exiting the final cooling tower in a timely manner during the production process, ensuring that when the temperature of the gas exiting the tower exceeds the regulations, especially when it is too high, the temperature of the gas exiting the tower can be quickly adjusted to the regulations according to the importance of each parameter affecting the temperature of the gas exiting the tower. This overcomes the defects of adjustment lag caused by only adjusting some parameters or insufficient human experience, or the defects of some parameters being processed to the limit while others are still operating at a low level, thus achieving the purpose of quickly and accurately optimizing the temperature of the gas exiting the final cooling tower. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments to facilitate a clearer understanding of the present invention, but these embodiments do not constitute a limitation on the present invention.

[0020] The final cooling tower is the front-end gas cooling tower in the benzene removal process of coking gas refining. The gas temperature T4 exiting the final cooling tower is the optimized control index for the final cooling tower. The optimal control range of T4 is 25~30℃ (the gas temperature T4 exiting the final cooling tower is taken as 20~35℃, mainly because the fluctuation of the commissioning data in normal production is beneficial to the usability of the fit and the guidance for subsequent production). The specific method is as follows:

[0021] 1) Evaluate the current operating condition of the final cooling tower by measuring the T4 temperature:

[0022] When 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature, the final cooling tower operates normally; otherwise, proceed to step 2) to optimize and adjust the gas temperature T4 exiting the final cooling tower; where the lean oil temperature is 27℃~32℃.

[0023] 2) Optimize and adjust the gas temperature T4 exiting the final cooling tower according to formula (1).

[0024] T4=m1×F1+m2×T1+m3×F2+m4×T2+m5×F3+m6×T3+m7×Z1+C (1)

[0025] Where m1, m2, ..., m6, m7 are the coefficients of formula (1), and C is the constant of formula (1); T4 is the temperature of the gas exiting the final cooling tower, F1 is the flow rate of the gas entering the tower, T1 is the temperature of the gas entering the tower, F2 is the flow rate of the upper circulating liquid, T2 is the temperature of the upper circulating liquid, F3 is the flow rate of the lower circulating liquid, T3 is the temperature of the lower circulating liquid, Z1 is the tower resistance entering the tower, m1, m2, ..., m6, m7 are the coefficients, and C is the constant; T4 is the target parameter, F1, T1 and Z1 are important parameters, and F2, T2, F3 and T3 are process adjustable parameters;

[0026] Furthermore: the temperature T2 of the upper circulating coolant is 10~34℃, the temperature T3 of the lower circulating coolant is 20~39℃, and the tower resistance Z1 of the final cooling tower is 0.5~2KPa;

[0027] When there are temperature fluctuations in the front-end process during maintenance and recovery, T1 is taken as 40~58℃; when there is a backup device in the front-end process connected to the final cooling tower, T1 is the value obtained by summing and averaging the values ​​in the range of 40~58℃.

[0028] F1, F2, and F3 are selected according to the range of values ​​under normal production conditions;

[0029] The specific optimization and adjustment process is as follows:

[0030] 21) Obtain the available data set closest to the adjustment time. The data set includes important parameters and adjustable parameters in the final cooling tower. There are ≥500 available data sets. Data during maintenance, shutdown and commissioning are unavailable data. The coefficients and constants in formula (1) are obtained by fitting the collected available data sets.

[0031] 22) Arrange the coefficients of F2, T2, F3, and T3 in descending order, and then adjust the process adjustable parameters corresponding to the first two coefficients;

[0032] The adjustment of the two process adjustable parameters is based on the average value of the 10 available data sets at the most recent time point of the current process adjustable parameter. If it is a flow parameter F2 or F3, the interval is 1% of the maximum flow rate. If it is a temperature parameter T2 or T3, the interval is 0.5℃. The adjustment is made in a direction that is favorable to T4 until the T4 calculated after substituting the adjusted process adjustable parameter into formula (1) satisfies 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature. Then the adjustment is terminated.

[0033] Example 1

[0034] The current operating conditions of the final cooling tower were evaluated. When T4 was 29℃ and the lean oil temperature was 32℃, the optimal control conditions for T4 were met, and production continued to operate normally.

[0035] Example 2

[0036] The current operating conditions of the final cooling tower are evaluated. T4 reaches 31℃, and the lean oil temperature is 31℃, which does not meet the optimal control conditions for T4. Therefore, the subsequent final cooling temperature adjustment program is initiated.

[0037] The gas temperature T4 exiting the final cooling tower is optimized and adjusted according to formula (1).

[0038] T4=m1×F1+m2×T1+m3×F2+m4×T2+m5×F3+m6×T3+m7×Z1+C (1)

[0039] Where m1, m2, ..., m6, m7 are the coefficients of formula (1), and C is the constant of formula (1); T4 is the temperature of the gas exiting the final cooling tower, F1 is the flow rate of the gas entering the tower, T1 is the temperature of the gas entering the tower, F2 is the flow rate of the upper circulating liquid, T2 is the temperature of the upper circulating liquid, F3 is the flow rate of the lower circulating liquid, T3 is the temperature of the lower circulating liquid, Z1 is the tower resistance entering the tower, m1, m2, ..., m6, m7 are the coefficients, and C is the constant; T4 is the target parameter, F1, T1 and Z1 are important parameters, and F2, T2, F3 and T3 are process adjustable parameters;

[0040] Furthermore: the temperature T2 of the upper circulating coolant is 10~34℃, the temperature T3 of the lower circulating coolant is 20~39℃, and the tower resistance Z1 of the final cooling tower is 0.5~2KPa;

[0041] When there are temperature fluctuations in the front-end process during maintenance and recovery, T1 is taken as 40~58℃; when there is a backup device in the front-end process connected to the final cooling tower, T1 is the value obtained by summing and averaging the values ​​in the range of 40~58℃.

[0042] F1, F2, and F3 are selected according to the range of values ​​under normal production conditions;

[0043] The specific optimization and adjustment process is as follows:

[0044] Obtain the available data set closest to the adjustment time. The data set includes important parameters and adjustable parameters in the final cooling tower. There are ≥500 available data sets. Data during maintenance, shutdown and commissioning are unavailable data. The coefficients and constants in formula (1) are obtained by fitting the collected available data sets.

[0045] By fitting the equation, we obtain the coefficients and constants in formula (1), resulting in: 0.0000518112*F1+0.2696765085*T1-0.009798848*F2+0.6390443396*T2+0.0159150556*F3+0.5153342776*T3-2.52915952*Z1-33.26184636

[0046] Arrange the coefficients of F2, T2, F3, and T3 in descending order, and then adjust the process adjustable parameters corresponding to the first two coefficients; adjust the first two parameters according to the magnitude of the correlation coefficients to be the upper section circulating liquid flow rate of F2 and the lower section spray liquid temperature entering the final cooling tower of T3.

[0047] The adjustment of the first two parameters is based on the average of the 10 sets of data at the most recent time point of the current parameter. The total time interval of the 10 sets of data is ≤4h, and there is no abnormal data. The flow rate F2 is adjusted in intervals of 1% of the maximum flow rate, and the temperature T3 is adjusted in intervals of 0.5℃. The adjustment is made in the direction that is conducive to the decrease of T4, that is, F2 is increased and T3 is decreased. Other parameters are substituted into the formula according to the most recent time data and are not adjusted. The adjustment is terminated when the T4 calculated after the adjustable parameters of the process are substituted into the formula (1) satisfies 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature. The optimal adjustment value of F2 is 1458.28m3 / h and the optimal adjustment value of T3 is 26.69℃ (rounded to two decimal places).

[0048] The proposed adjustment values ​​of 1458.28 m3 / h for the upper circulating liquid flow rate and 26.69℃ for the lower spray liquid entering the final cooling tower were applied to production adjustments. After production use, T4 was 27.8℃, which met the T4 control conditions: within 25℃~30℃, and when T4 is 2℃~4℃ lower than the lean oil temperature, the adjustment was terminated.

[0049] Example 3

[0050] The current operating conditions of the final cooling tower were evaluated. When T4 was 25℃ and the lean oil temperature was 25℃, the optimal control conditions for T4 were not met. The lean oil temperature was increased to 27℃~29℃.

[0051] Example 4

[0052] The current operating conditions of the final cooling tower are evaluated. T4 is 29℃ and the lean oil temperature is 29℃, which does not meet the optimal control conditions for T4. The T4 temperature is optimized and adjusted to 25℃~27℃.

Claims

1. A method for optimizing and adjusting a final cooling tower, characterized in that: The optimization and adjustment method is as follows: 1) Evaluate the current operating condition of the final cooling tower by measuring the gas temperature T4. If the evaluation conditions are met, the final cooling tower will operate normally; otherwise, proceed to step 2). 2) Optimize and adjust the gas temperature T4 exiting the final cooling tower according to formula (1). T4=m1×F1+m2×T1+m3×F2+m4×T2+m5×F3+m6×T3+m7×Z1+C (1) Where m1, m2, ..., m6, m7 are the coefficients of formula (1), and C is the constant of formula (1); T4 is the temperature of the gas exiting the final cooling tower, F1 is the flow rate of the gas entering the tower, T1 is the temperature of the gas entering the tower, F2 is the flow rate of the upper circulating liquid, T2 is the temperature of the upper circulating liquid, F3 is the flow rate of the lower circulating liquid, T3 is the temperature of the lower circulating liquid, and Z1 is the tower resistance entering the tower; T4 is the target parameter, F1, T1 and Z1 are important parameters, and F2, T2, F3 and T3 are process adjustable parameters; The specific optimization and adjustment process is as follows: 21) Obtain the available data set closest to the adjustment time. The data set includes important parameters and adjustable parameters in the final cooling tower. There are ≥500 available data sets. The coefficients and constants in formula (1) are obtained by fitting the collected available data sets. 22) Arrange the coefficients of F2, T2, F3, and T3 in descending order, and then adjust the process adjustable parameters corresponding to the first two coefficients until the adjusted process adjustable parameters are substituted into formula (1) and the calculated T4 satisfies 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature, then the adjustment is terminated. In step 2), the temperature T2 of the upper circulating liquid is 10~34℃, the temperature T3 of the lower circulating liquid is 20~39℃, and the tower resistance Z1 at the inlet of the tower is 0.5~2KPa. When there are temperature fluctuations in the front-end process during maintenance and recovery, T1 is taken as 40~58℃; when there is a backup device in the front-end process connected to the final cooling tower, T1 is the value obtained by summing and averaging the values ​​in the range of 40~58℃. In step 22), the adjustment of the two process adjustable parameters is based on the average value of 10 sets of available data at the most recent time point of the current process adjustable parameter. If it is a flow parameter F2 or F3, the interval is 1% of the maximum flow rate. If it is a temperature parameter T2 or T3, the interval is 0.5℃. The adjustment is made in a direction that is favorable to T4 until the T4 calculated after substituting the adjusted process adjustable parameter into formula (1) satisfies 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature. Then the adjustment is terminated.

2. The final cooling tower optimization and adjustment method according to claim 1, characterized in that: The evaluation criteria in step 1) are as follows: When 25℃≤T4≤30℃ and T4 is 2℃~4℃ lower than the lean oil temperature, the final cooling tower operates normally; otherwise, proceed to step 2) to optimize and adjust the gas temperature T4 exiting the final cooling tower.

3. The final cooling tower optimization and adjustment method according to claim 1, characterized in that: In step 21), the data during the maintenance, shutdown and debugging process is unusable data.