CN101874949A - Backwash regeneration method of ceramic membrane brine refining process filter - Google Patents

Abstract

The invention relates to the technical field of chlor-alkali chemical production, in particular to a backwash regeneration method for a ceramic membrane salt water refining process filter. The ceramic membrane primary brine filtration and refining process is a new type of refined brine filtration production process in the brine refining process of the chlor-alkali industry at home and abroad. At present, there are the following defects: high recoil frequency, unclean mud removal, and the membrane tube on the primary filter side is easy to be rough The salt mud and fibrous matter in the brine bridged and blocked, causing the pressure of the primary filter to rise above 0.5MPa; it had to be stopped for regeneration and cleaning, which affected normal production. In the present invention, the rough brine flows from the second stage to the first stage in the opposite direction, and then the refined brine side is forced to recoil several times, which can quickly reduce the filter pressure of the first stage filter to below 0.3MPa, restore normal production, and increase the production running time .

Description

Backwash regeneration method of ceramic membrane brine refining process filter

technical field

The invention relates to the technical field of brine refining technology in chlor-alkali chemical industry, in particular to a backwash regeneration method for a ceramic membrane method brine refining process filter.

Background technique

The ceramic membrane primary brine refining process is a new type of refined brine filtration production process in the brine refining process of the chlor-alkali industry at home and abroad. This process is popularized in domestic chlor-alkali industry in primary brine refining due to its advantages and characteristics such as short process flow, less equipment, less land occupation, low investment, low operating cost, and less auxiliary chemical refining agent. At present, the five chlor-alkali enterprises that use sea salt as raw material have high recoil frequency, unclean desilting, and membrane tubes on the primary filter side are easily blocked by salt mud and fibrous objects in coarse brine during production and operation, resulting in The primary filtration pressure is as high as 0.5MPa or more. Due to the small pressure difference, recoil failure (recoil pressure 0.45-0.5MPa; primary normal working pressure 0.35-0.4MPa) the filter flux decays, and the phenomenon that the filter has to be stopped for regeneration and cleaning. The regeneration and cleaning cycle is short, generally 7-10 days, and the production and operation efficiency is low, which affects the high-flux production capacity of the ceramic membrane and seriously affects the normal production.

Contents of the invention

The purpose of the present invention is to provide a backwash regeneration method for ceramic membrane brine refining process filter, which can quickly restore the filter flux without stopping the machine, and prolong the production and operation time of ceramic membrane brine filtration.

The concrete steps of technical scheme of the present invention are as follows:

a. When the filtration pressure on the primary side of the filter rises to 0.45MPa, close the refined brine outlet valve, isolate unqualified brine from entering the refined brine system, stop the operation of the filtration circulation pump, and reduce the pressure on the end face of the primary inlet membrane tube to 0.15-0.2 MPa.

b. Open the bottom valve of the first-stage side sewage of the filter and the return valve of unqualified brine, and turn on the first-stage feed pump, so that the coarse brine flows from the second stage to the reverse direction of the first stage at a pressure of 0.2-0.28MPa, and the flow rate is 0.7m/s , to form a brine back flushing pressure difference of 0.12-0.15MPa, to separate the salt mud agglomeration and impurities on the inner wall and end surface of the membrane tube and discharge it out of the filter through the sewage outlet.

c. After the crude brine flows in the reverse direction for 10 minutes, select the manual operation in the automatic control system to implement forced recoil on the refined brine side, with a flow rate of 1.4m/s on the membrane surface, 1-3 times, 10 seconds each time.

d. After the crude brine runs in the reverse direction for 20 minutes, start the crude brine filtration circulation pump, open the bypass circulation valve, close the first-stage side sewage bottom valve, stop the operation of the first-stage feed pump, and observe the filter pressure on the first-stage side of the filter , if it is below 0.35MPa, take a sample and analyze the results after 5 minutes of circulation, close the bypass circulation valve, open the refined brine outlet valve, and connect the system to resume normal operation.

The technical solution of the present invention is aimed at the high-pressure cross-flow working principle adopted by the ceramic membrane brine refining and filtering device currently using sea salt as raw material. Due to the pressure provided by the circulating pump on the primary side of the filter, the crude brine inlet of the primary brine filter side appears. The end face is easy to form salt mud and fibrous impurities in the coarse brine to block the ceramic membrane tube channel and the recoil effect is not good due to the small pressure difference. Take measures to reduce the inlet pressure of the first stage by 0.15-0.2MPa during the backwashing process, and the circulating brine flows from the second stage to the reverse direction of the first stage. The inner wall of the membrane tube and the gravity of the agglomeration are washed by the back flushing of the brine. The salt mud agglomeration and impurities on the end face are separated and discharged from the filter through the sewage outlet. Regular cleaning will reduce the potential chance of the membrane tube channel being blocked by bridging of salt sludge and fibrous impurities in the coarse brine, which can keep the filter in a high-flux operating state for a long time, prolong the regeneration and cleaning cycle, and realize continuous large-scale industrial production.

The advantage of the present invention is that it effectively solves the problem that the membrane tube on the primary filtration side is clogged, the flux attenuation is caused by a large amount of impurities contained in the sea salt in the brine refining and filtration production device of the ceramic membrane filter, and the ceramic membrane cannot be used continuously. A question of flux advantages. The whole set of equipment does not stop, does not consume chemical agents, does not increase energy consumption, and the first-stage filtration pressure can be kept below 0.35MPa for a long time by backwashing for 10-30 minutes per week, maintaining a high filtration flux, and the regeneration cleaning cycle is changed from 10 days If it is extended to more than 30 days, the production and operation time can be increased by 36 hours per month, and the production and operation time of the filter can be extended by about 400 hours per year, saving about 15 cubic meters of high-purity hydrochloric acid cleaning agent.

Description of drawings

Fig. 1 is a schematic diagram of the present invention

Detailed ways

When salt mud and fibrous impurities form ceramic membrane tubes to bridge and block the initial stage, backwash regeneration should be carried out. The specific steps are as follows:

a. When the filtration pressure on the primary side of the filter rises to 0.45MPa, close the refined brine outlet valve, isolate unqualified brine from entering the refined brine system, stop the operation of the filtration circulation pump, and reduce the pressure on the end face of the primary inlet membrane tube to 0.15-0.2 MPa.

b. Open the bottom valve of the first-stage side sewage of the filter and the return valve of unqualified brine, and turn on the first-stage feed pump, so that the coarse brine flows from the second stage to the reverse direction of the first stage at a pressure of 0.2-0.28MPa, and the flow rate is 0.7m/s , to form a brine back flushing pressure difference of 0.12-0.15MPa, to separate the salt mud agglomeration and impurities on the inner wall and end surface of the membrane tube and discharge it out of the filter through the sewage outlet.

c. After the coarse brine flows in reverse for 10 minutes, select the manual operation in the automatic control system to implement forced recoil on the refined brine side, with a membrane surface flow rate of 1.4m/s, 1-3 times, 10 seconds each time; the number of recoils It can be determined according to the scaling on the inner wall of the crude brine channel of the membrane tube.

d. After the crude brine runs in the reverse direction for 20 minutes, start the crude brine filtration circulation pump, open the bypass circulation valve, close the first-stage side sewage bottom valve, stop the operation of the first-stage feed pump, and observe the filter pressure on the first-stage side of the filter , if it is below 0.35MPa, take a sample and analyze the results after 5 minutes of circulation, close the bypass circulation valve, open the refined brine outlet valve, and connect the system to resume normal operation.

Claims (1)

1. a method for backwashing regeneration of ceramic membrane method brine refining process filter is characterized in that concrete steps are as follows: a. When the filtration pressure on the primary side of the filter rises to 0.45MPa, close the refined brine outlet valve, isolate unqualified brine from entering the refined brine system, stop the operation of the filtration circulation pump, and reduce the pressure on the end face of the primary inlet membrane tube to 0.15-0.2 MPa; b. Open the bottom valve of the first-stage side sewage of the filter and the return valve of unqualified brine, and turn on the first-stage feed pump, so that the coarse brine flows from the second stage to the reverse direction of the first stage at a pressure of 0.2-0.28MPa, and the flow rate is 0.7m/s , to form a brine reverse flushing pressure difference of 0.12-0.15MPa, to separate the salt mud agglomeration and impurities on the inner wall and end surface of the membrane tube and discharge it out of the filter through the sewage outlet; c. After the crude brine flows in the reverse direction for 10 minutes, select the manual operation in the automatic control system to implement forced recoil on the refined brine side, with a membrane surface flow rate of 1.4m/s, 1-3 times, 10 seconds each time; d. After the crude brine runs in the reverse direction for 20 minutes, start the crude brine filtration circulation pump, open the bypass circulation valve, close the first-stage side sewage bottom valve, stop the operation of the first-stage feed pump, and observe the filter pressure on the first-stage side of the filter , if it is below 0.35MPa, take a sample and analyze the results after 5 minutes of circulation, close the bypass circulation valve, open the refined brine outlet valve, and connect the system to resume normal operation.

Images