Control of carbon disulfide emissions from viscose processes

The U.S. Environmental Protection Agency (EPA) has issued a proposed rule for control of hazardous air pollutants from cellulose manufacturing operations. Both the hydrogen sulfide and carbon disulfide emissions must be controlled. An activated carbon‐based process has been developed which effectively removes both of these hazardous compounds with high efficiency. An impregnated activated carbon is used to remove hydrogen sulfide by converting it to sulfur on the interior surface of the activated carbon. The resulting waste is minimal and can be land filled at relatively low cost. A unique type of activated carbon is used to remove the carbon disulfide from the air stream, and periodic regeneration of the carbon, using hot inert gas, recovers the carbon disulfide for reuse. This type of system has operated for several years with no safety problems associated with the low auto‐ignition temperature of carbon disulfide. Extensive laboratory tests have been conducted to optimize this process and the results are presented. A large system has been designed and installed, and typical operating information is provided. Capital costs for systems of various sizes and configurations are given.