Post-processing and purification system for tail gas of ship engine

Abstract

The invention discloses a post-processing and purification system for removing PM and NOx ship tail gas through catalyzing and cooperating low-temperature plasma, specifically suitable for the tail gas purification treatment of a ship adopting diesel oil as fuel power and a diesel-powered generator set with a fixed source, etc. The system removes soot particles (PM) and NOx by a catalyst in cooperation with the low-temperature plasma, the system is composed of an oxidation type catalytic unit, a plasma generator, an oxidation type particle semi-permeable filter and a selective reduction catalytic unit, and is integrated in sequence; the number of pores of the catalytic unit containing the catalyst is between 20 meshes and 100 meshes, and the wall porosity of the oxidation type particle semi-permeable filter is more than or equal to 50%. The whole system has a low back pressure and can purify PM and NOx rapidly, the PM capture rate is more than 90%, the removal efficiency is more than 95%, and the NOx conversion efficiency is more than or equal to 95%.

Description

technical field [0001] The invention belongs to the technical field of tail gas purification, in particular to the technical field of catalytic purification of engine tail gas, and in particular to a post-treatment purification system for ship engine tail gas. Background technique [0002] Diesel engines have the advantages of high fuel economy, high reliability, high power, and long life, and are widely used in large-scale equipment such as automobiles, ships, fixed source generator sets, and offshore oil platform diesel generators. However, diesel exhaust pollution also poses a great threat to the human living environment. Diesel engine exhaust mainly includes water vapor, O 2 , N 2 , CO and CO 2 , hydrocarbons (HC), nitrogen oxides (NO X ), sulfide and particulate pollutants (PM), particulate pollutants mainly include soot particles, highly soluble hydrocarbons, lead compounds, etc., of which nitrogen oxides (NO X ) and particulate pollutants (PM) are the main compon...

AI Technical Summary

Problems solved by technology

However, there are also some disadvantages. The first is that the SCR reactor and scrubber are large in size and difficult to arrange. If it is aimed at the transformation of the ship in use, it will be very difficult. At the same time, it will have a great impact on the back pressure of the diesel engine, and generally need to be installed Fans are also very expensive

[0006] According to the current methods of PM capture and removal, on the one hand, diesel particulate filters are used for filtration, air blowing is used for physical purging, or burners are used for external heating to achieve direct combustion, all of which will bring There are many disadvantages. On the one hand, the purging is not thorough, and the soot will accumulate quickly, resulting in a rapid increase in back pressure. On the other hand, it is heated by the burner, and the energy consumption is high. When a large amount of soot is collected and burned directly, the filter The temperature of the core may increase sharply, resulting in unsafe conditions. Another way is to combine soot with NO under certain temperature conditions through catalytic oxidation. 2 Oxidation-reduction reactions occur, usually requiring a temperature of 280°C to 500°C, and sufficient NO 2 When the temperature is below 280°C, the catalytic ability is not enough, and the oxidation removal efficiency of soot is low. When the ship engine is operated under a low load for a long time, it will cause soot emission sharply, and the back pressure will increase sharply

At the same time, ships usually require the back pressure to be lower than 10kPa, which requires a large volume of diesel soot particulate filter, correspondingly, it takes up a lot of space on the ship, and some ships cannot be installed in a reasonable layout, so they cannot be widely used

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