Marine exhaust gas after-treatment method

Abstract

The invention discloses a marine exhaust gas after-treatment method. Exhaust gas generated by ships is introduced into a desulfurization and denitrification unified tower, absorbing desulfurization is conducted on the lower portion of the tower by means of sodium hydroxide solution, complexing denitrification can be achieved with complexing liquid on the upper portion of the tower, and exhaust gas up to standard after desulfurization and denitrification treatment is heated and then discharged out of a chimney; the complexing liquid after NO complexing is heated so that NO can be extracted; No extracted through heating is oxidized to be NO2 through catalytic oxidation or plasma oxidization, and then absorbed by sodium hydroxide solution or sodium sulfite solution. When ship usage meets the requirement for low-sulfur oil according to IMO convention, desulfurization is not needed, sodium alkali desulfurization section spraying liquid is changed to be seawater, and exhaust gas is cooled to prevent the temperature of a tower body from becoming too high. When ships sail in an area which does not need denitrification, a denitrification section complexing liquid sprinkling system is closed, and exhaust gas is heated and then directly discharged out of the chimney. In this way, separation and enrichment of NOX from exhaust gas is achieved, the concentration of NOx is improved, and the conversion rate of catalytic oxidation and plasma oxidization is increased.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to a treatment method for ship tail gas, in particular to a post-treatment method for ship tail gas. Background technique [0002] With the increasingly stringent emission limit standards of IMO and the ever-expanding ECA area, covering my country's major trading countries, it has had a great impact on the foreign trade transportation undertaken by my country's ships. In order to continue to play the important role of ships in the national economy and foreign trade, it is necessary to develop green and low-energy ship exhaust emission treatment devices. [0003] At present, the sodium-alkali desulfurization method is mainly used for desulfurization of ships, and the SCR method is mainly used for denitrification. There are some problems in the integration process of these two processes. The main reason is that only low-sulfur oil can be used for denitrification by SCR method. Although d...

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Problems solved by technology

[0005] Aiming at the above-mentioned technical problems in the prior art, the present invention provides a post-treatment method for ship exhaust gas. The post-treatment method for this ship exhaust gas should solve the problem of low catalytic activity and short service life of low-temperature SCR catalysts in the prior art. , the technical problem that only low-sulfur oil can be used

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