| abstract |
Carbon dioxide is produced from oxyfuel fired glassmaking furnace effluent gas by a series of steps including quenching the waste gas with aqueous quench liquid, comprising a solution of carbonate having a pH in the range of 6-5 to 8, thereby cooling the effluent gas and converting at least part of said sulphate to particulate sulphur salt, filtering particulate sulphur salt from the gas, and returning the particular sulphur salt to the furnace. The filtered gas is preferably scrubbed with aqueous carbonate to convert any remaining sulphur dioxide to an aqueous sulphite suspension and using the suspension as part or all of the above-mentioned aqueous quench liquid. The sulphur dioxide-free waste gas is preferably contacted with ammonia in the presence of a catalyst that selectively converts nitrogen oxides to nitrogen, thereby removing substantially all nitrogen oxides from the waste gas, and the resulting effluent gas stream is separated to produce a pure carbon dioxide product. The catalytic conversion is preferably performed in a series of at least two reactors, the feed gas temperature decreasing and the ratio of ammonia to total nitrogen oxides increasing as the feed gas passes from reactor to reactor. |