Method for stabilizing solid-liquid ratio during salt discharge process

Abstract

The application relates to the technical field of salt making, and discloses a solid-liquid ratio stabilizing method in a salt discharging process, which is a control method for periodically adjusting the valve opening degree according to the solid-liquid ratio of the material liquid in an evaporation tank and periodically setting the valve to a larger opening degree in a short time, so that the solid-liquid ratio of the material liquid is maintained stable, and the accumulation of salt blocks at the valve port is avoided to inhibit the salt precipitation, and the problem that the solid-liquid ratio cannot be accurately controlled by manual operation in the existing salt making industry and the block salt accumulation phenomenon occurs when the ball valve is kept at a smaller opening degree is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of salt production, and specifically relates to a method for stabilizing a solid-liquid ratio in a salt discharge process for stabilizing the solid-liquid ratio in an evaporator. Background Art

[0002] In the salt production industry of the prior art, workers in a liquid level chamber generally manually adjust a ball valve at a salt leg to change the salt discharge amount, so as to discharge large salt lumps and stabilize the solid-liquid ratio of material liquid in an evaporator. However, this method has several defects: since it is required to control the solid-liquid ratio in real time, operators need to frequently manually adjust the ball valve, resulting in low working efficiency; moreover, manual operation of the ball valve is relatively dependent on the operating experience of the operators, it is difficult to achieve the effect of accurately controlling the solid-liquid ratio in real time, it is relatively difficult to control the process parameters of the whole process, and the quality of finished products cannot be guaranteed; in addition, when the ball valve keeps a small opening, the phenomenon of salt lump accumulation will occur in about ten minutes, which may cause unsmooth or even interrupted salt discharge due to valve jamming, so that equipment in subsequent processes runs at no load, wasting energy, while keeping a large opening of the ball valve will result in a too small solid-liquid ratio in the evaporator, leading to reduced salt discharge amount and lowered working efficiency. Summary of the Invention

[0003] To mainly solve the problems existing in the salt production industry of the prior art that it is difficult for manual operation to accurately control the solid-liquid ratio, and salt lump accumulation occurs when the ball valve keeps a small opening, the present invention provides a method for stabilizing a solid-liquid ratio in a salt discharge process.

[0004] The method for stabilizing a solid-liquid ratio in a salt discharge process comprises the following steps: S1: setting a target solid-liquid ratio as a reference value; S2: acquiring a current actual solid-liquid ratio and a valve opening P in real time, determining whether the current solid-liquid ratio is within a range of ±5% of the target solid-liquid ratio, maintaining the current valve opening if the condition is satisfied, and repeatedly executing step S2; if the condition is not satisfied, continuing to execute step S3; S3: setting a timer parameter t, period values T1, T2, and an opening A, wherein T1>T2, and the opening A ranges from 70% to 90%, if t≥T1, keeping the valve at the opening A within the period T2, adjusting the valve opening back to be equal to the opening before executing step S3 after the period T2, and resetting t to zero; if t<T1, continuing to execute step S4; S4: setting a period T3, and openings B and C, wherein T3<T1 and C<P<B<A, periodically comparing the magnitude relationship between the current solid-liquid ratio and the target solid-liquid ratio, if the current actual solid-liquid ratio is greater than the target solid-liquid ratio, keeping the valve at the opening B within the period T3; if the current actual solid-liquid ratio is smaller than the target solid-liquid ratio, keeping the valve at the opening C within the period T3; S5: Return to execute step S2 and subsequent steps.

[0005] In the above technical solution, the opening value B must be at least 20% greater than the actual valve opening value P but less than 60%, and the opening value C must be at least 20% smaller than the actual valve opening value P.

[0006] A method for stabilizing the solid-liquid ratio during the salt removal process, based on the above technical solution, includes the following steps: S1: In the control system, a plurality of solid-liquid ratio signal value levels are preset. Each solid-liquid ratio signal value level corresponds precisely to the opening degree of the control valve, and the output signal value corresponding to each level of the control valve opening is obtained. The rest is the same as step S1 in the above technical solution. S2: Same as step S2 in the above technical solution; S3: Obtain the output signal value x corresponding to the current solid-liquid ratio signal according to step S1, and the rest of the settings are the same as step S3 in claim 1; S4: Based on the gear position in step S1, adjust the valve opening to the opening value corresponding to the output signal value x, and return to execute step S2; In the two technical solutions mentioned above, the range of cycle T1 is between 5 and 10 minutes, and the range of cycle T2 is between 10 and 15 seconds. The specific values ​​are set according to the working conditions.

[0007] The beneficial effects of this invention include: by periodically adjusting the valve opening according to the solid-liquid ratio of the discharged salt, and periodically setting the valve to a larger opening for a short period of time, the control method realizes automatic adjustment of the valve opening and avoids the accumulation of salt blocks at the valve opening. This solves the problems in the salt production industry of the prior art, such as the difficulty in accurately controlling the solid-liquid ratio by manual operation and the phenomenon of salt block accumulation when the ball valve is kept at a small opening. Attached Figure Description

[0008] Figure 1 This is a logic block diagram of the control method according to Embodiment 1 of the present invention; Figure 2 This is a logic block diagram of the control method in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram showing the correspondence between the solid-liquid ratio and the valve opening in Embodiment 2 of the present invention; Figure 4 This is a schematic diagram illustrating the beneficial effects of the present invention. Detailed Implementation

[0009] The present invention will now be described with reference to the accompanying drawings.

[0010] Example 1: like Figure 1 As shown, the method for stabilizing the solid-liquid ratio during the salt removal process of the present invention includes the following steps: S1: setting a target solid-liquid ratio as a reference value, and subsequent control steps perform judgment based on the reference value; S2: acquiring current actual solid-liquid ratio and valve opening P in real time, judging whether the current solid-liquid ratio is within the range of target solid-liquid ratio ±5%, keeping the current valve opening and repeatedly executing step S2 if the condition is met; proceeding to execute step S3 if the condition is not met; S3: setting a timer time parameter t, periodic values T1, T2 and an opening A, wherein the timer time parameter t increases with time and is used to periodically judge whether to increase the opening to discharge possibly accumulated block salt, T1>T2, according to practical experience, it is reasonable to set the range of opening A between 70% and 90%, if t≥T1, the valve keeps the opening A within the period T2, after the period T2, the valve opening is回调 to the opening equal to that before executing step S3, and t is reset to zero, so as to discharge possibly existing large block salt; proceeding to execute step S4 if t<T1; S4: setting a period T3, openings B and C, wherein T3<T1, C<P<B<A, periodically comparing the magnitude relationship between the current actual solid-liquid ratio and the target solid-liquid ratio, if the current actual solid-liquid ratio is larger than the target solid-liquid ratio, the valve keeps the opening B within the period T3 to reduce the solid-liquid ratio in the container; if the current actual solid-liquid ratio is smaller than the target solid-liquid ratio, the valve keeps the opening C within the period T3 to increase the solid-liquid ratio in the container; S5: returning to circularly execute step S2 and subsequent steps, so as to achieve the purpose of periodically regulating the solid-liquid ratio in the container and periodically discharging large block salt.

[0011] Further, in the above method for stabilizing the solid-liquid ratio in the salt discharge process, the opening value B is at least 20% larger than the actual valve opening P but less than 60%, and the opening value C is at least 20% smaller than the actual valve opening P.

[0012] Further, in the above technical solution, T1 ranges from 5 to 10 min, T2 ranges from 10 to 15 s, and the specific values are set according to working conditions.

[0013] In the implementation process of the present invention, the above technical solution can be introduced into a DCS system for control. First, a reference value of solid-liquid ratio is set, then the current solid-liquid ratio is obtained and compared with the reference value. If it fluctuates within the range of ±5% of the reference value, it meets the requirements, and the current valve opening is maintained unchanged. If the difference from the reference value exceeds ±5%, the subsequent control steps are carried out. First, it is determined whether t is less than T1. If t is not less than T1, the valve opening is maintained at opening A for a period T2, and after the period T2, the valve is adjusted back to the opening before the period T2, wherein T1>T2, A is between 70% and 90%, and the specific values of T1, T2 and A are determined according to working conditions. Under the working conditions described in this embodiment, T1 generally does not exceed 5min, T2 generally does not exceed 15s, and A is set to 90%. If t is less than T1, the magnitude relationship between the current actual solid-liquid ratio and the target solid-liquid ratio is periodically compared. If the current actual solid-liquid ratio is greater than the target solid-liquid ratio, the valve opening is adjusted to B within a period T3. If the current actual solid-liquid ratio is less than the target solid-liquid ratio, the valve opening is adjusted to C within a period T3. After the period T3, the comparison between the current actual solid-liquid ratio and the target solid-liquid ratio and subsequent control steps are repeated, wherein T3<T1, C<P<B<A. Under the working conditions described in this embodiment, B=P+20%, C=P-20%, and T3 is generally set to 3min.

[0014] Example 2: As shown in Figures 2-3 , the method for stabilizing the solid-liquid ratio in the salt discharge process of the present invention comprises the following steps: S1: preset a plurality of solid-liquid ratio signal value gears in the control system, each solid-liquid ratio signal value gear precisely corresponds to the control valve opening, and obtain the output signal value corresponding to each gear of control valve opening, the remaining steps are the same as step S1 in Embodiment 1; S2: same as step S2 described in Embodiment 1; S3: obtain the output signal value x corresponding to the current solid-liquid ratio signal according to step S1, the remaining settings are the same as step S3 described in Embodiment 1; S4: adjust the valve opening to the opening value corresponding to the output signal value x according to the gears in step S1, set t=0, and return to execute step S2.

[0015] Further, in the above technical solution, T1 ranges from 5 to 10min, and T2 ranges from 10 to 15s, and the specific values are set according to working conditions.

[0016] In the implementation of this invention, the above control method can be introduced into a DCS control system. First, a plurality of solid-liquid ratio signal value levels are preset, each level precisely corresponding to the valve opening. The output signal value corresponding to each valve opening level is obtained. A solid-liquid ratio reference value is set, and the current solid-liquid ratio is obtained and compared with the reference value. If it fluctuates within ±5% of the reference value, it meets the requirements, and the current valve opening remains unchanged. If the difference from the reference value exceeds ±5%, subsequent control steps are performed. The output signal value x corresponding to the current solid-liquid ratio signal is obtained according to step 1, and then it is determined whether t is small. For T1, if t is not less than T1, the valve opening is maintained at opening A within cycle T2, and after cycle T2, the valve is adjusted back to the opening before cycle T2, where T1>T2, A is between 70% and 90%, and the specific values ​​of T1, T2 and A are determined according to the working conditions. Under the working conditions described in this embodiment, T1 generally does not exceed 5 minutes, T2 generally does not exceed 15 seconds, and A is set to 90%. If t is less than T1, the valve opening is adjusted to the opening value corresponding to the output signal value x according to the gear in step S1, and then the comparison between the current actual solid-liquid ratio and the target solid-liquid ratio and subsequent control steps are repeated.

[0017] Compared with existing technologies, the solid-liquid ratio stabilization method proposed in this invention during the salt discharge process has the following advantages: By adjusting the valve opening according to the salt discharge solid-liquid ratio, and periodically setting the valve to a larger opening for a short period of time, the method achieves automatic adjustment of the valve opening and avoids the accumulation of salt blocks at the valve opening. Figure 4 As shown, after automation is implemented, the amount of salt discharged can be automatically adjusted in real time based on the solid-liquid ratio signal. The solid-liquid ratio inside the tank can be maintained stably at around 20%, and the control precision is greatly improved. The tank process parameters, such as the temperature of the liquid material, the temperature of the secondary steam, and the pressure, are significantly closer to the design values ​​of the vacuum salt production system, ensuring continuous and efficient salt production. This solves the problems in existing salt production technologies, such as the difficulty in accurately controlling the solid-liquid ratio through manual operation, the cumbersome adjustment process, low work efficiency, and the accumulation of lumpy salt when the ball valve is kept at a small opening.

Claims

1. A method for stabilizing the solid-liquid ratio during salt removal, characterized in that, Comprising the following steps: S1: setting a target solid-liquid ratio as a reference value; S2: acquiring a current actual solid-liquid ratio and a valve opening P in real time, determining whether the current solid-liquid ratio is within the range of the target solid-liquid ratio ±5%, keeping the current valve opening if the condition is met, and repeating step S2; continuing to perform step S3 if the condition is not met; S3: setting a timer time parameter t, period values T1, T2 and an opening A, wherein T1 > T2, and the opening A is in the range of 70% to 90%; if t ≥ T1, keeping the valve at the opening A within the period T2, adjusting the valve opening back to be equal to the opening before performing step S3 after the period T2, and resetting t to zero; continuing to perform step S4 if t < T1; S4: setting a period T3, openings B and C, wherein T3 < T1 and C < P < B < A; periodically comparing the magnitude relationship between the current actual solid-liquid ratio and the target solid-liquid ratio, keeping the valve at the opening B within the period T3 if the current actual solid-liquid ratio is greater than the target solid-liquid ratio; keeping the valve at the opening C within the period T3 if the current actual solid-liquid ratio is less than the target solid-liquid ratio; S5: returning to perform step S2 and subsequent steps.

2. The method for stabilizing the solid-liquid ratio during the salt removal process according to claim 1, characterized in that: The opening B is at least 20% greater than the actual valve opening P and less than 60%, and the opening C is at least 20% less than the actual valve opening P.

3. The method for stabilizing the solid-liquid ratio during the salt removal process according to claim 1 or 2, characterized in that: T1 ranges from 5 to 10 min, and T2 ranges from 10 to 15 s, and specific values are set according to working conditions.

4. A method for stabilizing the solid-liquid ratio during salt discharge, based on the method for stabilizing the solid-liquid ratio during salt discharge as described in claim 1, characterized in that: Comprising the following steps S1: pre-setting a plurality of solid-liquid ratio signal value gears in a control system, each solid-liquid ratio signal value gear accurately corresponds to a control valve opening, acquiring an output signal value corresponding to each gear of control valve opening, and the rest is the same as step S1 in claim 1; S2: being the same as step S2 in claim 1; S3: obtaining an output signal value x corresponding to a current solid-liquid ratio signal according to step S1, and the rest of the settings are the same as step S3 in claim 1; S4: adjusting the valve opening to the opening corresponding to the output signal value x according to the gears in step S1, and returning to perform step S2.

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