Wellman-Lord sulfur dioxide recovery process

The adaptability of this sulfur dioxide reduction technology to a feed gas containing 100% sulfur dioxide (dry basis) will be demonstrated at the D. H. Mitchell Station of the Northern Indiana Public Service Co. (NIPSCO) at Gary, Indiana (8). In this application the process will be combined with the Wellman-Lord sulfur dioxide recovery process to provide a complete flue gas desulfurization system for a 115-MW coal-fired boiler in a project jointly funded by NIPSCO and the Environmental Protection Agency. 

Recent Experience of the Wellman-Lord Sulfur Dioxide Recovery Process... 

At Chiba, Japan, the Japan Synthetic Rubber Co. has two steam boilers with evaporation rates of 130 metric tons/hr, each equipped with Wellman-Lord sulfur dioxide recovery units. The load to each scrubber is essentially constant, but sulfur dioxide concentration varies from 400 to 2,000 ppm because of the varying quantities of waste process gas from the plant. 

The Wellman-Lord process can be a significant factor in helping domestic power plants to meet the air pollution abatement requirements of the Clean Air Act of 1970. To show its applicability to the utilities industry, Davy Powergas Inc. is building a demonstration installation at the Dean H. Mitchell Station of Northern Indiana Public Service Co. in Gary, Ind. When completed, it will consist of a Wellman—Lord sulfur dioxide recovery unit connected to an Allied Chemical Co. sulfur dioxide-to-sulfur reduction process to produce elemental sulfur. Davy Powergas guarantees emissions of 200 ppm by volume or less of sulfur dioxide at this facility. 

Processes that have been successful in other industrial applications presently are being studied for inclusion in the Wellman-Lord process. This would allow the system to operate as a closed loop with total sodium and sulfur dioxide recovery and would eliminate eflluent streams requiring treatment. Further test work is necessary, however, before including another idea into the commercially proved process. 

The third class of control systems may use any of the sulfur dioxide control systems among those used commercially are the Haldor Topsoe (5, 80), Wellman-Lord (27, 07), and Chiyoda (27, 07, 87) systems. The circumstances are generally highly favorable for recovery processes that produce a stream of concentrated sulfur dioxide, since this can be recycled to the Claus plant. The application of processes that produce sulfuric acid or solid wastes will be dictated only by peculiar local circumstances. 

---