A Low-Cost System for the Conversion of HCl to Cl2

65141 In the production of chlorinated hydrocarbons and titanium dioxide pigments, elemental chlorine (Cl2) is used as a reactant and hydrochloric acid (HCl) is produced as an unavoidable byproduct. Stringent environmental regulations limit the shipment of hazardous wastes like HCl, and the disposal of HCl by neutralization is costly. Although processes exist for converting waste HCl back to Cl2, they become too expensive when the concentration of the waste HCl is low. This project will develop improvements to a new process that uses a regenerable sorbent to recover HCl from waste streams. Previous work showed that the new process has the potential to reduce the cost of Cl2 to less than half of the cost of fresh chlorine. In Phase I, improved sorbents were produced and tested under process conditions. Multiple cycle tests showed that the improved sorbent has the potential to convert waste HCl to chlorine over a long lifetime at approximately half the cost of buying fresh chlorine. In Phase II, sorbents will be made by techniques representative of commercial production, and then screened to identify the best composition. Key design features will be evaluated. Commercial Applications and Other Benefits as described by the awardee: HCl waste streams (from vinyl chlorine monomer, other chlorinated organics, and titanium dioxide manufacturing) could be reclaimed to produce approximately 850,000 tons of Cl2 per year. The new conversion process should consume only 13% of the electrical energy required for electrolytic production of fresh chlorine (an 87% reduction) and also reduce fuel/steam consumption by 65%.