Pure water systems for chlor-alkali enterprises
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This post was last edited by sunjl1981 on 2013-1-6 20:05. Question: What types of equipment are commonly used by chlor-alkali companies to produce pure water? Which device is more cost-effective? # ， ， &
The pure water preparation method used in the former chlor-alkali plant where I worked was an anion exchange bed + cation exchange bed + mixed exchange bed.
Hey, you two upstairs – what’s the purity rate of your water products?
Previously, it consisted of an iron remover + weak acid hydrogen ions + strong acid cations (two chambers) + a decarburization tower + an anion bed (two chambers), with a capacity of 30 T/H
It would be best to use reverse osmosis combined with a mixed-bed system now
RO combined with mixed-bed systems are widely used; our factory also employs RO reverse osmosis units along with mixed-ion resin exchangers (mixed beds) to produce pure water. The resistivity of the pure water we produce can reach 15 M ohms! The RO membranes in our factory are chemically cleaned every two months. The specific cleaning chemicals depend on the dirt present on the surface of the RO membranes. The chemicals and steps for cleaning are as follows: 3.4.4.1 Chemicals a) Acidic cleaning solution: A 1% citric acid solution, whose pH value is adjusted to 3 using ammonia water, is used for cleaning. b) Alkali wash: 0.5% sodium hydroxide solution. 3.4.4.2 Cleaning steps a) Open the outlet valve of the cleaning agent preparation tank in the RO membrane reverse osmosis system, and fill the tank with the amount of water required to prepare the cleaning agent ； b) Prepare the appropriate chemicals and stop the operation of the RO membrane reverse osmosis system ； c) Close the inlet valve, drain valve, and product water valve of the RO membrane unit, and open the inlet cleaning valve and outlet cleaning valve ； d) Open the inlet and outlet valves of the cleaning pump, and start the cleaning pump. Check whether there is any return of chemical solution in the cleaning agent preparation tank, and whether there are any leaks at the connections of the cleaning agent pipes; run the cleaning process for 1 hour ； e) Stop the operation of the cleaning pump, and close the inlet and outlet cleaning valves of the RO membrane permeation unit ； f) Open the inlet valve, drain valve, and product water valve of the RO membrane unit, start the high-pressure pump for water washing, and continue washing until the desalination rate reaches 97% as required, after which proceed to normal operation.
The new production rate is not less than 70; as long as the water quality is fine, that’s sufficient
Our company has two methods for preparing pure water: (1) anion exchange bed + cation exchange bed + mixed exchange bed; (2) reverse osmosis. Each has its advantages.
We adopted two processes: 1. The traditional process: electrodialysis + cation-anion exchange resins； 2. New process: reverse osmosis + mixed bed
We use reverse osmosis here; if the conductivity does not meet the standards, we resort to a mixed-bed system