Brief description of the production process
The material goes through the following stages in the carbonization furnace.
(1) Drying stage (≤160℃): The water is evaporated, and the main components of the material remain unchanged.
(2) Pyrolysis 1 (160-260°C): Most of hemicellulose and part of cellulose and lignin are decomposed, and hemicellulose is decomposed to produce wood acid, carbon dioxide and water.
(3) Pyrolysis 2 (260-310°C): mainly cellulose is decomposed, and the solid product of the decomposition residue of hemicellulose is further aromatic.
(4) Carbonization (310-450℃): mainly lignin is thermally decomposed, wood vinegar is gradually reduced, and wood gas is discharged in large quantities.
(5) Calcination stage (>450°C): as the temperature increases, the carbonyl group, carboxyl group, hydroxyl group, methyl group, etc. are detached and condensed and polycyclic aromaticization proceeds further, and the amount of hydrogen generated gradually increases. Above 500°C, so Hydrogen is mainly produced. The calcination stage relies on external heat to volatilize the volatiles remaining in the charcoal.
The following stages are experienced in the activation furnace.
(1) Heating stage (≤700°C): The material continues to heat up, and the carbon is calcined at high temperature, and the residual volatile matter is volatilized to generate H2, CO, CH4, CO2 and other combustible gases.
(2) Activation stage (700-900°C): use water vapor and gases such as CO2 generated by the oxidation reaction in the calcination stage to open the micropores of the carbon, and gasify the carbon blocked in the carbon pores, thereby increasing the adsorption performance. The residence time in the activation stage is about 120-180min. The reaction principle is as follows:
C+H2O→CO+H2
CO+H2O→CO2+H2
C+CO2→2CO
