Exhaust gas processing system and processing method
First Claim
1. An exhaust gas processing system, comprising:
- a desulfurization unit having a gas inlet portion from which an exhaust gas introduced, that removes a sulfur oxide from the exhaust gas by a limestone/gypsum method;
a denitration unit arranged in a subsequent stage from the desulfurization unit to remove a nitrogen oxide from the exhaust gas;
a drying unit arranged in a subsequent stage from the denitration unit and having a desiccant to remove water from the exhaust gas;
a carbon dioxide recovery unit arranged in a subsequent stage from the drying unit to recover carbon dioxide from the exhaust gas by separating the exhaust gas into carbon dioxide and a post-recovery gas in which carbon dioxide is reduced; and
an oxygen supply unit having a pipe through which the post-recovery gas is discharged from the carbon dioxide recovery unit via the drying unit and a branch pipe branched from the pipe and connected to the desulfurization unit, that supplies a fraction of the post-recovery gas discharged from the carbon dioxide recovery unit, as an oxygen source, to the desulfurization unit through the branch pipe,wherein the desiccant of the drying unit is regenerated with the post-recovery gas discharged from the carbon dioxide recovery unit through the pipe, andwherein the oxygen supply unit comprises;
a monitor having an analyzer for monitoring a purity and a recovery ratio of the recovered carbon dioxide recovered by the carbon dioxide recovery unit; and
flow rate adjusting valves provided on the pipe and the branch pipe, that adjust a proportion of the fraction of the post-recovery gas to be supplied to the desulfurization unit in the post-recovery gas discharged from the carbon dioxide recovery unit, based on the purity and the recovery ratio of the recovered carbon dioxide which are monitored by the monitor, thereby enabling a supply condition that impurity is not excessively concentrated in the exhaust gas to be supplied to the carbon dioxide recovery unit.
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Accused Products
Abstract
An exhaust gas processing system having excellent durability and good desulfurization and denitration efficiency is provided to efficiently recover carbon dioxide with high purity and reduced processing costs. The exhaust gas processing system has: a desulfurization unit removing sulfur oxides from the exhaust gas by the limestone-gypsum method; a denitration unit arranged downstream of the desulfurization unit to remove nitrogen oxides from the exhaust gas; a carbon dioxide recovery arranged downstream of the denitration unit to recover carbon dioxide from the exhaust gas; and an oxygen supply unit supplying to the desulfurization unit with a faction of the recovered gas from the carbon dioxide recovery unit as oxygen source. An analyzer is used to monitor the purity and recovery ratio of the carbon dioxide recovered, and the supplied ratio of recovered gas is adjusted, based on the monitored purity and recovery ratio.
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Citations
9 Claims
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1. An exhaust gas processing system, comprising:
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a desulfurization unit having a gas inlet portion from which an exhaust gas introduced, that removes a sulfur oxide from the exhaust gas by a limestone/gypsum method; a denitration unit arranged in a subsequent stage from the desulfurization unit to remove a nitrogen oxide from the exhaust gas; a drying unit arranged in a subsequent stage from the denitration unit and having a desiccant to remove water from the exhaust gas; a carbon dioxide recovery unit arranged in a subsequent stage from the drying unit to recover carbon dioxide from the exhaust gas by separating the exhaust gas into carbon dioxide and a post-recovery gas in which carbon dioxide is reduced; and an oxygen supply unit having a pipe through which the post-recovery gas is discharged from the carbon dioxide recovery unit via the drying unit and a branch pipe branched from the pipe and connected to the desulfurization unit, that supplies a fraction of the post-recovery gas discharged from the carbon dioxide recovery unit, as an oxygen source, to the desulfurization unit through the branch pipe, wherein the desiccant of the drying unit is regenerated with the post-recovery gas discharged from the carbon dioxide recovery unit through the pipe, and wherein the oxygen supply unit comprises; a monitor having an analyzer for monitoring a purity and a recovery ratio of the recovered carbon dioxide recovered by the carbon dioxide recovery unit; and flow rate adjusting valves provided on the pipe and the branch pipe, that adjust a proportion of the fraction of the post-recovery gas to be supplied to the desulfurization unit in the post-recovery gas discharged from the carbon dioxide recovery unit, based on the purity and the recovery ratio of the recovered carbon dioxide which are monitored by the monitor, thereby enabling a supply condition that impurity is not excessively concentrated in the exhaust gas to be supplied to the carbon dioxide recovery unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification