Mitsubishi Heavy Industries Limited

Kenichi Okada

Shintaro Honjo

Susumu Okino

Yasuhiro Takeuchi

Tsuyoshi Oishi

Toru Takashina

Kozo Iida

Naoyuki Kamiyama

Kazuto Kobayashi

Satoru Sugita

Masashi Yoshikawa

Shigeru Nojima

Yoshio Nakayama

Tsumoru Nakamura

Tsuyoshi Ohishi

Masanori Tabata

Kouzou Takano

Provided is a system for removing mercury from a mercury-containing exhaust gas, which contains a mercury chlorinating agent feed unit for feeding a mercury chlorinating agent to an flue exhaust gas containing nitrogen oxide, sulfur oxide and mercury, a reductive denitration unit for reducing the nitrogen oxide, and a desulfurization unit for removing the sulfur oxide, characterized in that the mercury chlorinating agent feed unit further comprises a heating unit for heating a non-gaseous agent for mercury chlorination which is in the non-gaseous form under normal temperature and normal pressure or a gasifying unit for obtaining a gaseous agent for mercury chlorination from the non-gaseous agent for mercury chlorination. The present invention makes it possible to provide a mercury removal process and system which have high reliability and can be operated at a low cost.

Mercury removal system and mercury removal process

The present invention provides a system for removing mercury in exhaust gas, in which mercury is removed from exhaust gas of a boiler, characterized in that between a denitrification apparatus and a wet type desulfurization apparatus, an NHdecomposition catalyst and a mercury oxidation catalyst are provided, and mercury having been oxidized into mercury chloride is removed by the wet type desulfurization apparatus. Also, it provides a method for removing mercury in exhaust gas, characterized in that the mercury removing method includes an NHdecomposition process and a mercury oxidation process, which are provided between the denitrification process and a wet desulfurization process, and mercury having been oxidized into mercury chloride is removed in the wet desulfurization process.

Method for removing mercury in exhaust gas

A liquid column type exhaust gas treatment apparatus comprising a spray header () for injecting an absorbing solution upward in an absorption tower (), wherein exhaust gas introduced from a lower part of the absorption tower () and the absorbing solution injected from the spray header () are brought into gas-liquid contact with each other, by which desulfurization of exhaust gas is accomplished, characterized in that drift preventing plates (and) are provided in a liquid top portion of a liquid column () formed by the absorbing solution and/or at the installation position of the spray header ().

Exhaust gas treatment apparatus

Provided is an exhaust gas treating tower in which exhaust gas flow velocity is increased more than a prior art case so that exhaust gas treating efficiency can be enhanced or the exhaust gas treating tower can be made compact if equivalent performance is to be maintained. Also, an exhaust gas treating tower ensuring a liquid recovery is provided. In an exhaust gas treating towerA, liquid columns C are generated and also a liquid drop generating memberis provided to thereby generate liquid drops M therearound to be floated. Also, liquid is spouted from spray nozzles to thereby generate liquid films F in area different from the liquid columns C. In an exhaust gas treating tower, a liquid drop eliminatoris provided upstream of a mist eliminator. Interval Pof collecting platesof the liquid drop eliminatoris made larger than interval Pof collecting platesof the mist eliminator. Thereby, liquid drops having larger particle diameter contained in the exhaust gas are collected by the liquid drop eliminator

Exhaust gas treating tower

The present invention provides an exhaust gas treatment method including oxidation treatment for converting metallic mercury contained in combustion exhaust gas into mercury chloride; and mercury removal treatment for removing mercury from the combustion exhaust gas by dissolving the mercury chloride in water, wherein a plurality of oxidation catalysts for performing the oxidation treatment are provided, and during the time when the oxidation treatment is performed, at least one of the oxidation catalysts performs catalyst performance restoration treatment without performing oxidation treatment. According to the present invention, the deterioration in mercury removal performance can be restrained even in continuous operation on condition that mercury is oxidized in a low temperature region not higher than 300&#xb0; C.

Exhaust gas treatment method, exhaust gas treatment system, and catalytic oxidation apparatus

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Hiroshima-ken, Japan

Kenichi Okada