A plasma-based waste-treatment process will be installed in Dow Corning Corp.’s silicon-products-manufacturing plant in Midland, Mich., where it will recycle chemical wastes, help lower the site’s consumption of natural gas by 400-billion Btu/yr and help reduce the plant’s total emissions by 75%. The installation will mark the first use of the technology in a chemical process plant, says Jeffrey Surma, CEO of Integrated Environmental Technologies, LLC (IET, Richland, Wash.; edlinks.chemengonline.com/6901-532), which owns the technology. In its initial installations, the plasma-enhanced melter (PEM) is being used to destroy medical wastes and chemical wastes, he says.
The PEM is a vessel that contains a molten glass bath, above which are graphite electrodes that generate a plasma arc. In the Dow Corning plant, waste chlorosilanes (from intermediate products) will be fed into the plasma arc. Organics in the waste will be gasified to a hydrogen-rich syngas and removed, along with hydrogen chloride. The HCl will be scrubbed and condensed out of the mixture and recycled to the plant, while the syngas will be mixed with waste gas streams from other plant operations. These gases will be treated in a thermal oxidizer and used to raise steam. Meanwhile, in the PEM, silicon from the waste will fall into the bath, forming a relatively small amount of inert waste.
IET will own and operate the PEM, scheduled to start up in mid 2008 under an agreement with Dow Corning, says Surma. “We will generate about 10.5-million Btu/h of syngas for steam and make 12-million lb/yr of HCl,” he says.