Combustion Equipment Associates, Inc.

Arthur D. Little, Inc.

Edwin L Field

James R Valentine

Charles R Lamantia

James E Oberholtzer

Richard R Lunt

Process for distillatively separating a liquid mixture containing at least two miscible volatile components having different boiling points using low-grade heat and, if necessary, low-grade cooling. Distillation is carried out at a pressure sufficiently low to cause the mixture at the bottom of the distillation column to boil below the temperature of the low-grade heat supplied and condensation of at least a portion of the vapor fraction is carried out at a pressure which permits using available cooling liquid. Condensed liquid is returned as reflux to the distillation column at a temperature and pressure essentially equal to the temperature and pressure prevailing near the top of the column. The progressive increase of vapor recompression in the system makes it possible to provide an increasing proportion of the energy to the system in the form of electrical energy, up to the total energy requirement. The process and apparatus of this invention are particularly suited to separating ethyl alcohol from dilute aqueous mixtures, where the formation of the ethyl alcohol azeotrope can be reduced or eliminated.

Process for distillatively separating liquid mixtures

Method and apparatus for removing sulfur dioxide from stack gases. The stack gases are scrubbed with an aqueous wash liquid containing one or more alkali metal compounds which react to form the bisulfite, sulfite and sulfate salts of the alkali metal. The spent absorbent liquid effluent is then treated with calcium compounds in at least two separate reaction stages, the conditions of ion concentration and pH of the first stage being maintained to favor the precipitation of calcium sulfate in the presence of SO.sub.3.sup.= ions. In the succeeding reaction stages the precipitation of the desired amount of SO.sub.3.sup.= ions is carried out to form calcium sulfite. The resulting compound of calcium with sulfite and sulfate (which may in part be in the form of mixed crystals) are removed and the regenerated liquid is recycled.

Apparatus for removing sulfur dioxide from stack gases

Method and apparatus for removing sulfur dioxide from stack gases. The stack gases are scrubbed with an aqueous wash liquid containing one or more alkali metal compounds which react to form the bisulfite, sulfite and sulfate salts of the alkali metal. The spent absorbent liquid effluent is then treated with calcium compounds in at least two separate reaction stages, the conditions of ion concentration and pH of the first stage being maintained to favor the precipitation of calcium sulfate in the presence of SO.sub.3.sup.= ions. In the succeeding reaction stages the precipitation of the desired amount of SO.sub.3.sup.= ions is carried out to form calcium sulfite. The resulting compounds of calcium with sulfite and sulfate (which may in part be in the form of mixed crystals) are removed and the regenerated liquid is recycled.

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Lexington, MA, United States of America

Edwin L Field