CN-121988158-A - Cross-tower coupling stability control system and method for viscose fiber spinning bath desulfurization

CN121988158ACN 121988158 ACN121988158 ACN 121988158ACN-121988158-A

Abstract

The invention relates to the technical field of desulfurization process control, in particular to a cross-tower coupling stable control system and method for viscose fiber spinning bath desulfurization, wherein the feed flow, the tower top pressure and the absorption liquid density and temperature are obtained in real time to calculate the saturation degree of absorption liquid, the change rate of the feed flow and the change rate of the tower top pressure, further judge the gas change trend, wake up a source sink sensing module in response to the judging result of the gas surge trend, calculate the gas propagation time and the concentration load increment through the gas concentration of an outlet of a reaction tower and an inlet of the absorption tower to determine the gas mass impact state, and formulate a cross-tower cooperative control strategy based on the gas mass impact state. The invention breaks the control island of the reaction tower and the absorption tower, realizes the precise identification and grading regulation of the impact gas mass, greatly reduces the energy consumption and maintenance cost of the instrument while ensuring that the absorption tower is not broken down and the environment-friendly emission continuously reaches the standard, and takes the safety, the economy and the running stability of the system into consideration.

Inventors

XU JINCHENG
ZHENG TINGTING
WANG XIAOQIANG
Su Zhanli

Assignees

莱特莱德(上海)技术有限公司

Dates

Publication Date: 20260508
Application Date: 20260410

Claims (10)

1. A cross-tower coupling stability control system for viscose fiber spinning bath desulfurization comprises an oxidant supply unit, a gas pipeline and a liquid pipeline: the oxidant supply unit comprises a preparation tank, a delivery pump and a gasifier which are connected in sequence; The liquid pipeline comprises a middle receiving tank, a transfer pump, a filter and a receiving tank which are sequentially connected, and the outlet of the gasifier is connected with the bottom of the reaction tower; The gas pipeline comprises a feed pump, a reaction tower, an absorption tower and a fan which are sequentially connected, and the bottom of the absorption tower is connected with a circulating pump to form an absorption liquid circulating loop; characterized by further comprising: the conventional monitoring module is arranged at the top of the feeding pipeline, the reaction tower and the circulating pump outlet pipeline and is used for acquiring the feeding flow of the spinning bath, the gas pressure at the top of the reaction tower and the density and temperature of the absorption liquid respectively; The source-sink sensing module comprises a first laser gas analyzer and a second laser gas analyzer, wherein the first laser gas analyzer and the second laser gas analyzer are used for monitoring the gas concentration at the top of the reaction tower and the gas concentration at the bottom of the absorption tower; The conventional analysis module is used for calculating the density temperature change rate of the absorption liquid in real time according to the density and the temperature of the absorption liquid to determine the saturation degree of the absorption liquid, and judging the gas change trend according to the gas pressure change rate and the feed flow change rate at the top of the reaction tower; The sensing control module is used for responding to the judging result of the gas change trend to determine whether to wake up the source sink sensing module, calculating gas propagation time and concentration load increment according to the gas concentration of the top of the reaction tower and the bottom of the absorption tower at different moments, determining the gas mass impact state, and formulating a control strategy based on the gas mass impact state, and comprises the following steps: formulating a control strategy in response to the dominant impact condition; or, in response to the hidden impact state, formulating a control strategy in combination with the absorbent saturation level.
2. The cross-tower coupling stability control system for viscose fiber spinning bath desulfurization according to claim 1, wherein the conventional analysis module generates a time-varying density curve and a temperature curve according to the density and temperature of the absorption liquid, calculates instantaneous slopes of the density curve and the temperature curve as a density change rate and a temperature change rate, respectively, and determines a density temperature change rate according to a ratio of the density change rate to the temperature change rate to determine the saturation degree of the absorption liquid, comprising: Determining that the saturation degree of the absorption liquid is in a near-saturation state according to the judgment result that the density temperature change rate exceeds a saturation trend threshold; The density temperature change rate is used for representing the density change amount corresponding to unit temperature change.
3. The cross-tower coupling stability control system for viscose fiber spinning bath desulfurization according to claim 1, wherein the conventional analysis module calculates a gas pressure change rate and a feed flow rate change rate according to a gas pressure at the top of a reaction tower and a spinning bath feed flow rate of a circulation pump outlet pipeline, respectively, and judges a gas change trend according to the gas pressure change rate and the feed flow rate change rate, wherein: Determining that the gas variation trend is a gas surge trend in response to the gas pressure variation rate being greater than a preset pressure variation rate and the feed flow variation rate exceeding a preset flow variation rate; And otherwise, judging the gas change trend as a gas stabilization trend.
4. The cross-tower coupling stability control system for viscose fiber spinning bath desulfurization according to claim 1, wherein the perception control module wakes the source sink perception module in response to a gas surge trend, and calculates a gas propagation time and a concentration load increment according to gas concentrations at the top of the reaction tower and the bottom of the absorption tower.
5. The cross-tower coupled stability control system for viscose fiber spin bath desulfurization according to claim 4, wherein the perception control module is configured to calculate the gas propagation time according to the following procedure: identifying a starting time when the gas concentration at the gas outlet at the top of the reaction column is continuously increased and is higher than a source concentration threshold value for the first time; Recognizing response time when the gas concentration at the gas inlet at the bottom of the absorption tower exceeds the concentration threshold and keeps rising trend for at least 3 continuous sampling periods; determining a time difference between the start time and the response time as the gas propagation time; Wherein the gas propagation time is used to characterize the length of time required for an impact gas mass to propagate from the reaction column to the absorption column.
6. The cross-tower coupling stability control system for viscose fiber spinning bath desulfurization according to claim 4, wherein the perception control module integrates the gas concentration at the gas inlet at the bottom of the absorption tower in time within a time period corresponding to the gas propagation time, and determines the integration result as the concentration load increment; Wherein the concentration duty increase is used to characterize the total load of the impact gas mass that is flushed into the absorber column during the gas propagation time.
7. The cross-tower coupled stable control system for viscose fiber spinning bath desulfurization according to claim 6, wherein the perception control module determines a gas mass impact state according to the gas propagation time and the concentration load increment, comprising: Determining that the air mass impact state is a dominant impact state in response to the air travel time being less than a preset travel time and the concentration load delta being greater than a preset load delta; And otherwise, determining the air mass impact state as a hidden impact state.
8. The cross-tower coupled stability control system for viscose fiber spinning bath desulfurization according to claim 7, wherein the perception control module formulates a control strategy based on the air mass impact state, comprising: in response to the dominant impact condition, a control strategy is formulated to reduce the feed load to the reaction column and increase the fan frequency of the absorber column at a preset safety slope.
9. The cross-tower coupled stability control system for viscose fiber spinning bath desulfurization according to claim 1, wherein the perception control module formulates a control strategy based on the air mass impact state, further comprising: formulating a control strategy in response to the recessive impact condition in combination with the absorption liquid saturation level, wherein: If the saturation degree of the absorption liquid is near saturation, a control strategy is formulated to preheat the standby heat exchanger and the absorption liquid supply system, and the circulating flow of the absorption tower is improved according to a preset safety amplitude; if the saturation degree of the absorption liquid is in an unsaturated state, a control strategy is not formulated and the reaction tower and the absorption tower are not actively interfered.
10. A cross-tower coupling stability control method for viscose fiber spinning bath desulfurization, which is applied to the cross-tower coupling stability control system for viscose fiber spinning bath desulfurization according to any one of claims 1 to 9, and is characterized by comprising the following steps: Continuously obtaining the feeding flow of the spinning bath, the gas pressure at the top of the reaction tower and the density and temperature of the absorption liquid, and calculating the density and temperature change rate of the absorption liquid in real time according to the density and temperature of the absorption liquid so as to determine the saturation degree of the absorption liquid; Respectively calculating a gas pressure change rate and a feed flow rate change rate according to the gas pressure at the top of the reaction tower and the feed flow rate of the spinning bath to judge a gas change trend, wherein the gas change trend comprises a gas surge trend and a gas stabilization trend; The source sink sensing module is awakened in response to the gas sudden increase trend, and gas propagation time and concentration load increment are calculated according to the gas concentration of the top of the reaction tower and the bottom of the absorption tower at different moments; determining a gas mass impact state according to the gas propagation time and the concentration load increment, wherein the gas mass impact state comprises a dominant impact state and a recessive impact state; Formulating a control strategy based on the air mass impact state, comprising: responding to the dominant impact state to formulate a control strategy, wherein the formulation control strategy is to reduce the feeding load of the reaction tower and improve the fan frequency of the absorption tower according to a preset safety slope; or, in response to a recessive impact condition in combination with the absorbent saturation level, developing a control strategy in which: If the saturation degree of the absorption liquid is near saturation, a control strategy is formulated to preheat the standby heat exchanger and the absorption liquid supply system, and the circulating flow of the absorption tower is improved according to a preset safety amplitude; if the saturation degree of the absorption liquid is in an unsaturated state, a control strategy is not formulated and the reaction tower and the absorption tower are not actively interfered.

Description

Cross-tower coupling stability control system and method for viscose fiber spinning bath desulfurization Technical Field The invention relates to the technical field of desulfurization process control, in particular to a cross-tower coupling stability control system and method for viscose fiber spinning bath desulfurization. Background In the viscose fiber production process, spin bath desulfurization is a key process for ensuring the quality of products and reaching the standard of environmental protection, and a typical desulfurization system comprises a reaction tower (oxidation tower) and an absorption tower (tail gas absorption tower). The spinning bath solution is pumped into the upper part of the reaction tower through a feed pump, the oxidant enters from the lower part of the reaction tower through a preparation tank, a delivery pump and a gasifier, oxidation desulfurization reaction is carried out in the reaction tower, the spinning bath after reaction is discharged from the bottom of the tower to enter a subsequent filtering and recycling process, the tail gas containing harmful gases such as H 2S、CS2 and the like generated by reaction is discharged from the top of the reaction tower, enters the lower part of the absorption tower through a gas pipeline, contacts with circulating absorption liquid in the absorption tower, and is pumped to the atmosphere by a fan to be discharged. In the prior art, a reaction tower and an absorption tower usually operate as two independent control units, the reaction tower adopts a single-point oxidation-reduction potential sensor to monitor the oxidation state in the tower and adjust the addition amount of an oxidant according to the oxidation state, the absorption tower detects the concentration of discharged tail gas by means of an online gas monitor at the top of the tower or timing sampling, and measures such as increasing the flow of circulating liquid, supplementing fresh absorption liquid and the like are adopted when the concentration of the discharged tail gas approaches to an exceeding threshold value. This control method has the following disadvantages: the reaction tower and the absorption tower lack of information intercommunication, the reaction tower only pays attention to oxidation efficiency, the absorption tower only pays attention to emission standard, and cross-tower coordination can not be formed; Only when the tail gas enters the absorption tower and even the emission is close to exceeding the standard, the absorption liquid can be close to the saturation regulation effect to be limited at the moment, so that the breakdown of the absorption tower (namely the saturation failure of the absorption liquid) is easy to cause the exceeding of the standard of environmental protection emission; When a large amount of sulfur-containing tail gas is generated by the reaction tower and flows into the absorption tower at a higher speed, an impact air mass is formed, the existing system cannot sense the source, scale and arrival time of the impact in advance, and remedial measures can be taken only after the impact occurs; The prior art generally only monitors the liquid level or the pH value of the absorption liquid, and cannot dynamically evaluate the residual absorption capacity of the absorption liquid, and when the absorption liquid is nearly saturated, even a small-amplitude impact can cause breakdown, but the prior system cannot adjust the control strategy according to the method. Disclosure of Invention Therefore, the invention provides a cross-tower coupling stability control system and method for viscose fiber spinning bath desulfurization, which aim at the problems in the background art, and solve the problems of how to realize the cross-tower coupling stability control of a reaction tower and an absorption tower under complex working condition fluctuation, how to intervene in advance before an impact air mass reaches the absorption tower, cut down load from the source and synchronously strengthen the downstream absorption capacity, and how to ensure that the absorption tower is not broken down and the environment-friendly emission continuously reaches the standard. In order to achieve the above object, in one aspect, the present invention provides a cross-tower coupling stability control system for viscose fiber spinning bath desulfurization, comprising an oxidant supply unit, a gas pipeline and a liquid pipeline: the oxidant supply unit comprises a preparation tank, a delivery pump and a gasifier which are connected in sequence; The liquid pipeline comprises a middle receiving tank, a transfer pump, a filter and a receiving tank which are sequentially connected, and the outlet of the gasifier is connected with the bottom of the reaction tower; The gas pipeline comprises a feed pump, a reaction tower, an absorption tower and a fan which are sequentially connected, and the bottom of the absorption tower is connected with a circulating pump to form