Wood-based activated carbon is made of high-quality sawdust, wood blocks, etc., and it is processed by physical methods, phosphoric acid methods, and zinc chloride methods. Due to these activated carbon manufacturing processes, the mesopore structure and specific surface area of wood-activated carbon are more abundant, the adsorption capacity is large, and the filtration speed is fast. The ash content is high, the pore size distribution is reasonable, and the ignition point is relatively high. Let’s take a look at the production of wood-activated carbon and what are the factors affecting wood-based activated carbon production.
What are the elements affecting wood-based activated carbon production?
In the wood-based activated carbon production line, there are many elements can affect the performance of finished products, such as raw material types, temperature, moisture, activation time, etc. As a trustable activated carbon production solution provider, we list six main elements that affect wood activated carbon plant.
The influence of sawdust tree species
Experiments have proved that the adsorption performance of wood activated carbon is closely related to sawdust tree species. In most cases, it is believed that the fir layer is better than pine sawdust, pine sawdust is better than hard miscellaneous sawdust, and soft wood is better than hard miscellaneous sawdust. The sawdust will affect the penetration rate of zinc chloride solution. However, choosing suitable production conditions and mixing wood chips as raw materials can also overcome the adverse effects of raw materials and produce qualified activated carbon.
Influence of moisture content of sawdust
but it will affect its penetration rate and thus its impregnation time. Especially important for continuous immersion or stirring processes. Sawdust with high water content (higher than the fiber saturation point) not only reduces the permeability of the zinc chloride solution, but also reduces the concentration of the zinc chloride solution, thereby affecting the activation effect of the carbon. The results show that when the moisture content of wood chips is greater than 30%, the soaking time is more than 8 hours, and when the moisture content of wood chips is below the saturation point, the permeability is slightly higher. When the water content is lower than 15%, the mixing time is shorter (15min). Wood moisture content also affects its uptake of zinc chloride solutions.
Effect of particle size of wood activated carbon
During the production of wood powder activated carbon, the particle size of wood powder is between 0.425-3.35mm, which has no obvious impact on product quality. Generally speaking, the particle size of the raw material is small, the impregnation effect is good, and the carbon-making adsorption performance is good. The uniformity of the particle size of the raw material sawdust has a certain influence on the quality of the product.
Effect of the zinc chip ratio of wood activated carbon
the ratio of anhydrous zinc chloride to the mass of dry wood chips, which is an important factor affecting the pore size distribution and porosity of wood activated carbon. In the activation material, the volume occupied by zinc chloride is approximately equal to the pore volume of activated carbon after recovery of zinc chloride. Compare zinc filings to an approximate measure of the degree of activation of the zinc chloride process. The performance of the activated carbon prepared is closely related with the ratio of zinc scrap used. When the impregnation rate is within a certain range, adding zinc chloride can significantly improve the adsorption and porosity of activated carbon.
Effect of activation temperature
activation temperature refers to the extremely high temperature of the activation material during the activation process, which is an important factor affecting the pore properties of activated carbon. The temperature of the better zinc chloride activated carbon is about 600°C. Excessively high activation temperature will cause the collapse of the existing pores and increase the volatilization of zinc chloride, which not only increases the waste of activator, but also increases the production cost. Moreover, it will cause serious environmental pollution problems.
Effect of activation time
activation time refers to the time at a certain activation temperature, which is one of the important factors affecting the quality of wood activated carbon. However, with the prolongation of the activation time, the generated pores are sintered and closed, causing the performance of the activated carbon to decline. It is better to select the activation time as 1h. When the activation time increased from 0.5h to 3.5h, the yield dropped from 43% to 29%, and the decline would be relatively fast in the first 1.25h, then it would reach 837.54mg/g/g, while in the first 1.25h Inside, the increase of mesopores is favorable, and as the activation time prolongs, the mesopores begin to collapse and become macropores.