US 7,833,501 B2 · Method and apparatus for treating discharge gas

Abstract

A method and apparatus for treating an exhaust gas comprising heavy metals, wherein the apparatus comprises a heat recovery unit, recovering exhaust gas heat at an exit of the air preheater; a precipitator, collecting soot/dust contained in an exhaust gas at an exit of the heat recovery unit; a wet flue gas desulfurizer, removing sulfur oxides contained in the exhaust gas at the exit of the precipitator; and a reheater, heating the exhaust gas at the exit of the wet flue gas desulfurizer. Each of the heat recovery unit and the reheater has a heat exchanger tube, and a circulation line is disposed to connect the heat exchanger tubes. A sulfur trioxide (SO3) removing agent is supplied to the upstream side of the heat recovery unit, and the temperature of the exhaust gas at the exit of the heat recovery unit is adjusted to not more than a dew point of sulfur trioxide.

Claims14

Dependent claims

A method of treating an exhaust gas comprising heavy metals comprising:

preheating a combustion air of a combustion apparatus by the exhaust gas comprising heavy metals discharged from the combustion apparatus;
recovering heat from the exhaust gas by a heat recovery unit after the air preheating;
recovering the heavy metals and soot/dust in the exhaust gas at an exit of the heat recovery unit by a dry precipitator;
supplying a sulfur trioxide removing agent into the exhaust gas at an upstream side of an entrance of the heat recovery unit;
and
lowering an exhaust gas temperature at the exit of the heat recovery unit to a dew point temperature of sulfur trioxide.

3 more elements

An apparatus for treating an exhaust gas comprising heavy metals comprising:

an air preheater, preheating a combustion air of the combustion apparatus by the exhaust gas comprising heavy metals discharged from the combustion apparatus;
a heat recovery unit, recovering heat from the exhaust gas at an exit of the air preheater;
a dry precipitator, recovering the heavy metals and soot/dust in the exhaust gas at an exit of the heat recovery unit;
which are successively disposed from an upstream side to a downstream side of an exhaust gas duct of a combustion apparatus;
a sulfur trioxide removing agent supply unit, supplying a sulfur trioxide removing agent into the exhaust gas at an upstream side of an entrance of the heat recovery unit;
and
an exhaust gas temperature controller, performing control to lower an exhaust gas temperature at the exit of the heat recovery unit to a dew point temperature of sulfur trioxide.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for treating discharge gas

Life of this patent

Method and apparatus for treating discharge gas

Life of this patent

Abstract

Claims14