Methods to control flue gas and inorganics precipitation

摘要

This invention presents innovative methods for desulfurizing flue gas in conjunction with selective inorganics recovery using calcium chloroaluminate or calcium chloroferrate as a layered double hydroxide reagent. One of the aspects of such methods is based on scrubbing SO2 in a standalone closed loop. Further aspects of such methods are based on scrubbing SO2 by the natural alkalinity of a saline stream as a once-through sink along with controlled precipitation of magnesium hydroxide and a calcium-based mineral in a standalone basis; or in conjunction with desalination methods and/or enhanced hydrocarbons recovery.

主权项

1. A method for scrubbing sulfur dioxide from flue gas using an aqueous stream enriched with calcium chloroaluminate or calcium chloroferrate, said method comprising the steps of:
(a) injecting said flue gas into a precipitator through at least one nozzle; (b) injecting said aqueous stream said enriched with calcium chloroaluminate or calcium chloroferrate into said precipitator through at least one nozzle to react said sulfur dioxide with calcium hydroxide crystals from said chloroaluminate or calcium chloroferrate to form precipitates comprising calcium sulfoaluminate or calcium sulfoferrate; (c) injecting an amine solvent into said precipitator through at least one nozzle to enhance said precipitates of said calcium sulfoaluminate or calcium sulfoferrate; (d) liberating carbon dioxide in a near pure form from said flue gas; (e) removing said precipitates of said calcium sulfoaluminate or calcium sulfoferrate from said aqueous stream or by filtering; (f) removing at least most of said amine solvent from said aqueous stream by stripping; (g) recycling said aqueous stream and said amine solvent to said precipitator.