Wood-pellet active carbon and preparation method thereof

Abstract

The invention discloses wood-pellet active carbon and a preparation method thereof, and belongs to the field of active carbon for a car carbon tank and a preparation method for the active carbon. Thewood-pellet active carbon adopts main raw material components of wooden activate carbon to organic sodium-based bentonite to water of 1 to (0.2-0.25) to (0.8-1.0), the three raw materials are uniformly mixed and then are pelletized, and are physically activated after being pelletized and dried in air to prepare the wood-pellet active carbon; the wood active carbon is prepared by mixing aged saw dust and hot-process food-stage phosphoric acid with concentration of 85% in a weight ratio of 1 to (1.2-1.5); the raw materials are sufficiently stirred and stewed, are carbonized and activated at a high temperature, are recycled, are rinsed, are dried in air and are prepared into powder. The preparation method comprises two main processes of preparing wood active carbon powder and preparing wood-pellet active carbon. The wood-pellet active carbon is high in product strength, is more advanced in effective aperture pore volume, is more uniform in distribution, is good in adsorption and desorption performance, and is small in gas flowing resistance.

Description

technical field [0001] The invention relates to the field of activated carbon for automobile canisters and a preparation method, in particular to a wood particle activated carbon combined with a chemical activation method and a physical activation method and a preparation method thereof. Background technique [0002] At present, with the increasingly stringent emission standards of automobiles and the mature application of automobile exhaust purification technology, the proportion of hydrocarbons in exhaust gas after fuel evaporation is gradually increasing in vehicle emissions. The carbon canister is a key component of gasoline vehicle fuel evaporation control, and its core material is shaped activated carbon for gasoline adsorption and desorption. The shaped activated carbon required by the carbon canister technology has a high specific surface area and high strength, requires an effective pore volume of 2-5mn, and must have the function of quickly adsorbing and desorbing ...

AI Technical Summary

Problems solved by technology

At present, the production process of activated carbon for automobile canisters used in the field of automobile production in my country is to use wood chips as raw materials, which are made by crushing, mixing, extrusion, drying, carbonization, and activation. The activated carbon produced in this way has the following defects : (1) The strength is low, because the wood chips are stirred and extruded with the chemical activator phosphoric acid, and then activated by high-temperature carbonization, and the wood chips will inevitably shrink and crack during the high-temperature carbonization activation after molding, and will occur during production. The mutual friction and collision between charcoal and charcoal will greatly reduce the strength of activated carbon. The product has low strength, uneven strength, severe powder loss, and is brittle.

(2) Poor adsorption and desorption performance, low service life

This production process of forming first and then carbonizing and activating cannot meet the production needs of high-quality formed activated carbon in the market, because activated carbon mainly produces effective pore size and pore volume in the process of carbonization and activation, that is to say, the more effective pore size and pore volume, the more The better the adsorption and desorption performance of developed activated carbon is, the existing traditional process is to adopt the production process of forming first and then activating. The product obtained by carbonization and activation, the product obtained by this production process, its pore structure and the distribution of pore size and pore volume are not uniform. It is found through the detection of pore structure and specific surface area analyzer that the surface pore diameter has 2 -7mn, the specific surface area is 1500 m 2 / g, while the middle part of the particle is only 0.5-2mn, and the specific surface area is only about 800; therefore, the activated carbon produced by the traditional process can only be adsorbed on the surface, and the activated carbon produced in this way only has a certain pore size, pore volume and functional groups on the surface. , it is difficult to have a standard pore volume inside, so its performance and working capacity will be greatly reduced, resulting in its short service life, poor performance and other defects

(3) The gas flow resistance is large, because the more developed the pore size and pore volume of activated carbon, the less its gas flow resistance, and the above-mentioned production process only has a certain pore size and pore volume on the surface, and the middle of the carbon cannot get effective. Carbonization activation, resulting in no pore size and pore volume inside the carbon column, so it has a large flow resistance to gas, which is not conducive to the adsorption and desorption of volatile solvents by activated carbon, reducing the recycling rate