Low-energy venturi pre-scrubber for an air pollution control system and method

The method of cleaning a gas stream in a pollution control system, said gas stream having entrained large abrasive particles, comprising:

• scrubbing the gas stream to remove a substantial portion of the large abrasive particles by spraying liquid droplets having a mean mass diameter in the range of about 200 micrometer to about 750 micrometer into said gas stream in a venturi scrubber, coalescing said droplets, and removing the coalesced droplets containing said large abrasive particles from the pollution control system, where said scrubbing occurs with a pressure drop;
• and
• thereafter, scrubbing the gas stream in a second venturi scrubber to remove the remaining finer particles entrained in the gas stream, wherein said scrubbing occurs with a pressure drop;
• wherein the first scrubbing step is preformed at a lower pressure drop than the second scrubbing step.

A method of cleaning a gas stream in a pollution control system, said gas stream having entrained particles, comprising:

• scrubbing the gas stream to remove a substantial proportion of the large particles by contacting liquid droplets with said gas stream in a venturi scrubber, coalescing said droplets, and removing the coalesced droplets containing said large particles from the pollution control system, where said scrubbing occurs with a pressure drop;
• and
• thereafter, scrubbing the gas stream in a venturi scrubber to remove the remaining finer particles entrained in the gas stream, wherein said scrubbing occurs with a pressure drop;
• wherein the first scrubbing step is performed at a lower pressure drop than second scrubbing step, and
• wherein said second scrubbing step includes contacting said gas stream with a second scrubbing liquid, wherein said coalesced drops of said first scrubbing step are disposed of, and wherein said second scrubbing liquid is recycled in said air pollution control system.

An air pollution control system for removing entrained particles from a gas stream comprising:

• a first scrubber to remove a substantial proportion of particles having a aerodynamic diameter of greater than about 2 micrometers, said first scrubber having
• a venturi scrubber with a gas stream pressure drop of from about 1″ H2O to about 10″ H2O, and
• a droplet generator to spray droplets into the gas stream, where said droplets comprise water with a mean mass diameter of from about 200 micrometers to about 750 micrometers, and
• a droplet separator to accept the gas stream and said water droplets from said venturi scrubber and remove said droplets from the gas stream;
• and
• a second scrubber to remove a substantial proportion of the particles not scrubbed from the gas stream from said first scrubber.