Research and production status of the ion membrane-saltwater denitration process
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This post was last edited by huawei on 2010-6-14 at 11:37. All members are encouraged to participate actively in voting, and please reply to indicate the scale of caustic soda production. All participants will receive different generous rewards based on their responses.
Denitration by membrane process, sodium sulfate recovery through cold crystallization; annual production of 180,000 tons of caustic soda. The denitration unit from Shanghai Kaimo is being used; it has been in operation for almost two years now, and it performs reasonably well at removing sulfate ions. The resulting mirabilite is not valuable, and it seems that the subsequent freezing system is a bit of a waste!
With an annual production capacity of 100,000 tons of caustic soda, barium-based denitration is used; previously, mixing and pressure filtration were employed, and the salt sludge was disposed of as waste in the calcium carbide slag dump. Recycling, clean production, and separate pressure filtration are now required, but the waste has piled up in large amounts with no signs of it being processed. :(
Denitration using the barium chloride method on a scale of 100,000 tons; barium sulfate is filtered separately. However, due to severe leakage from the filter presses, some of the barium solution mixes into the sludge tank containing calcium carbonate, resulting in the calcium sludge having a yellowish tint despite being white in color – which is not very attractive
Isn’t there a risk of being inspected for the discharge of concentrated liquids? **They are really strict about environmental protection efforts!
Membrane process + freezing, with an annual production capacity of 150,000 tons of caustic soda. A denitration unit from Shanghai Kaimo was used, and it has been in operation for 1 year. Personally, I tend to set the high-nitrate discharge level a bit higher. It seems that the freezing technology isn’t very mature yet.
Denitration by membrane process, sodium sulfate recovery through cold crystallization; annual production of 100,000 tons of caustic soda. For actual denitrification, as well as the design capacity of equipment such as pipelines, it is 150,000 tons per year. The *State Xinpuli denitrification unit is used; this unit has been in operation for over a year now. The efficiency in removing sulfate ions is somewhat below the designed level, but it is still acceptable. It has been running continuously for 8 months. At present, sulfate has little effect in the electrolyzer, and the chlorine purity remains within the range of 99.4% to 99.6% with no correction errors.
The barium chloride method involves the separate recovery of barium sulfate; it is in liquid form and not mixed with salt sludge. The annual production of caustic soda is around 200,000 tons.
Annual production of 100,000 tons, sulfate removal using the barium method.
In the barium-based removal method, the barium salts and salt sludge from the traditional saline process are mixed together without any separation equipment; the barium salts obtained through the HVM membrane process are provided at a reduced price or even for free.
My friend said that they also use the membrane method combined with freezing, and they employ denitration devices from Shanghai Kaimo! !