Dwinding mercury cell chlor-alkali

I might have mentioned before that my day job is actually writing a weekly column for ICIS Chemical Business magazine, and one of my market coverages involves chlor-alkali (the production of chlorine and caustic soda).

US chlor-alkali producer Olin announced in early December that it is exiting the use of mercury cell technology by the end of 2012 by closing its 100,000 ton/year Augusta, Georgia chlor-alkali production facility as well as converting its 260,000 ton/year Charleston, Tennessee, production from mercury cell to using membrane cell technology.



Olin said the Charleston plant will employ the most modern membrane technology which would result in lower operating costs and higher quality products produced.

“Over the past eighteen months we have experienced a steady increase in the number of our customers unwilling to accept our products manufactured using mercury cell technology. The conversion of the Charleston facility, which in addition to hlorine and caustic soda also produces potassium hydroxide, hydrochloric acid, and bleach, will prevent the potential loss of these valuable customers.”

Chlor-alkali producers currently use either mercury cell, diaphragm cell, or the more recently developed ion exchange membrane process. Within the past 3 years, the green blog previously reported about several chlor-alkali producers ceasing the use of mercury cell-based technology and transitioning to membrane cell technology instead.

The blog posted in 2008 about OxyChem’s decision to be the first mercury-free caustic potash producer in North America by ceasing all of its mercury cell based production in the region and converting its chlor-alkali plant at Taft, Louisiana into using membrane cell technology.

Early this year, we posted Bayer MaterialScience’s press release about a new chlorine production developed in collaboration with engineering company Uhde that is said to be more eco-friendly than the traditional membrane cell technology. Somebody from DuPont (or is it Dow? I forgot…) questioned how eco-friendly this new process can be. Unfortunately the only answer I can say based on the press release is that it is said to result in a 30% lower electricity consumption compared to traditional membrane cell technology.

ICB published a very interesting article in September about the move of Western chlor-alkali companies to membrane cell from mercury cell technology because of 1) regulatory pressures, 2) rising maintenance costs for outdated mercury cell plants, 3) membrane conversion will reportedly help producers save 20-30% in electricity costs, and boost output by more than 30% compared to mercury cell plants.

According to industry analysts, electricity is the largest cost factor in chlor-alkali production typically accounting for 40-50% of costs. 

While the ICB article mostly reported about European legislation pressures, in North America there is also pending potential mercury legislation in Congress, which would require chlor-alkali producers to either shut down their mercury cell plants by mid 2013 or convert to other technologies by mid-2015.

This decision has to be made by mid-2012 under the bill H.R. 2190, which is still waiting to be approved by both the House and the Senate. Mercury cell chlor-alkali capacity including those of Olin’s, are estimated at 474,000 short tons or 3% of total US chlor-alkali capacity.



[Photo of Olin's Augusta, GA facility]



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