Ship exhaust gas denitration system

Abstract

A marine exhaust denitration system comprises an exhaust denitration pipe, an exhaust direct-discharging pipe and a denitration reactor. The exhaust denitration pipe is connected with the exhausting end of a diesel engine through a first valve. The exhaust direct-discharging pipe is connected with the exhausting end of the diesel engine through a second valve, and comprises a main exhaust direct-discharging pipe and an exhaust direct-discharging branch. The denitration reactor comprises a reaction chamber and an exhaust channel. The reaction chamber is connected to the interior of the exhaust denitration pipe. The exhaust channel is connected to the interior of the exhaust direct-discharging branch. When the first valve is opened and the second valve is closed, exhaust passes through the exhaust denitration pipe, is denitrated in the reaction chamber and then is discharged; when the first valve is closed and the second valve is opened, part of exhaust is discharged out of the main exhaust direct-discharging pipe, and the rest of exhaust enters the exhaust channel of the denitration reactor via the exhaust direct-discharging branch to maintain the temperature of the reactor. By means of the exhaust channel and the exhaust direct-discharging branch, the exhaust conducts preheating and temperature maintaining on the reaction chamber of the denitration reactor, and energy consumption can be reduced.

Description

technical field [0001] The invention relates to the field of atmospheric environment protection, in particular to a ship exhaust gas denitrification system. Background technique [0002] According to the requirements of the amendments to the Regulations for the Prevention of Air Pollution from Ships in Annex VI of the MARPOL 73 / 78 Convention adopted by the International Maritime Organization (IMO), the nitrogen oxides in the exhaust gas of ships must be treated to meet the standards before they can be discharged. For low-speed marine diesel engines (speed n<130rpm), the nitrogen oxide content after treatment should be less than 3.4g / kwh, but for current low-speed diesel engines, this emission requirement cannot be met only by optimizing the combustion method of diesel engines. Therefore, marine diesel engines must be equipped with marine exhaust gas denitrification systems, and Selective Catalytic Reduction (SCR) technology is currently the most applicable diesel engine p...

AI Technical Summary

Problems solved by technology

For a ship using SCR technology, when sailing from a non-ECA area to an ECA area, the temperature in the SCR reactor is too low to meet the temperature required for the denitrification reaction; at the same time, due to the sealing problem of the valve, some exhaust gas may leak Entering the SCR reactor, if the SCR reactor is in a low temperature state for a long time, it will cause SO in the exhaust gas 3 Condensation, forming sulfuric acid, causing reactor corrosion, so preheating and heat preservation measures for SCR reactors are necessary

However, the traditional denitrification device uses electric heating to preheat and keep warm the SCR reactor, which consumes a lot of electricity, and the electric heating equipment ages quickly and has low efficiency.

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