RELIABLE REMOVAL OF MERCAPTANS AND OTHER ORGANIC SULFIDES USING SODIUM HYPOCHLORITE WET SCRUBBER TECHNOLOGY

We are beginning to expect more from our odor control equipment. No longer is system performance solely tied to hydrogen sulfide destruction. Frequently, new equipment specifications require odor control systems to remove mercaptans or other organic sulfides from a foul air stream.Expanded performance requirements increase the complexity of odor control equipment. Some malodorous compounds like hydrogen sulfide and mercaptans are most effectively scrubbed in high-pH solutions, whereas other organic sulfur compounds (dimethyl sulfide and dimethyl disulfide for example) are most effectively scrubbed in a low-pH solution. No longer will a single stage scrubber designed to remove just hydrogen sulfide do. Two scrubber stages are required where members of both compound groups are present in a foul air stream.Control of the sodium hypochlorite addition in both the high- and low-pH scrubbing environments has been a problem until recently. Oxidation Reduction Potential (ORP) sensors which effectively regulate sodium hypochlorite addition in wet scrubbers when the pH is high (above 9.0) are unstable and ineffective in lower pH solutions.Fortunately a cost effective and reliable controller using a completely different sensor technology is now available which solves this problem.