Post On : 16/12/2017
There are four things that can be a limitation of the decomposition of wood components that occur due to heating in the dry distillation process, namely:
1. The limit A is the heating temperature to 200 ° C. The water contained in the raw material becomes steam, so the wood becomes dry, cracked and bent. Carbon content of approximately 60%.
2. Limitations B is a heating temperature between 200-280 ° C. Wood gradually becomes charcoal and distillate. Charcoal color becomes dark brown and carbon content of approximately 700%.
3. Limit C is a heating temperature between 280-500 ° C. At this temperature there will be cellulose carbonization, decomposition of lignin and yield "ter". Charcoal formed black and its carbon content increased to 80%. The banding process practically ceases at a temperature of 400 ° C.
4. Limit D is a heating temperature of 500 ° C, a process of purification of charcoal, where the formation of "ter" is still ongoing. Carbon levels will increase to 90%. Heating above 700 ° C, producing only hydrogen gas.
But in general and simple process of manufacture:
1. Dehydration: the process of removing air where the raw material is heated to a temperature of 170 ° C.
2. Carbonization: the goods of organic materials into carbon. Temperatures above 170 ° C will produce CO, CO2 and acetic acid. At a temperature of 275 ° C, the decomposition produces "ter", methanol and other byproducts. Formation of Energy at a temperature of 400 - 600 0C
3. Activation: tar decomposition and expansion of pores. Can be done with steam or CO2 as an activator.
The process of activation is important to note in addition to the raw materials used. What is meant by activation is a treatment of suitable charcoal to enlarge the pore by solving the hydrocarbon bond or oxidizing the molecule - so that its physical, chemical, or chemical properties change, ie the surface area increases and affects the adsorption power. The activation methods commonly used in the manufacture of activated charcoal are:
1. Chemical Activation.
This activation is the process of breaking the carbon chain from organic yields by the use of chemicals. The activators used are chemicals such as: alkali metal hydroxides, carbonate salts, chlorides, sulfates, phosphates of alkaline earth metals and in particular ZnCl2, inorganic acids such as H2SO4 and H3PO4.
2. Physical Activation.
This activation is the process of breaking carbon chain from organic material with the aid of heat, steam and CO2. The charcoal is heated in a furnace at a temperature of 800-900 ° C. Oxidation with air at low temperatures is an exothermic reaction making it difficult to control it. With heating and steam at high temperatures is an endotherm reaction, making it more controllable and most commonly used.
Some raw materials are easier to activate if they are classified. It is then carbonized to remove chlorinated hydrocarbons and ultimately activated with steam. It is also necessary to weigh wood charcoal with sulfur vapor at a temperature of 500 ° C and then desulfurize with H2 and charcoal with high activity. In some ingredients activated by mixing of chemicals, a second activation is given to the vapor to provide certain physical properties.
With increasing distillation and increasing of distillation temperature, the amount of charcoal produced is smaller, while the distillation and absorption are getting bigger. Despite the increasing temperature of the distillation, the activated charcoal is getting better, the temperature is still not exceeding 1000 0C, because many formed ash so as to cover the pores that serve to adsorb. As a result the active charcoal absorption will decrease. Furthermore the mixture of charcoal and activator is heated at a certain temperature and time. The resulting result, the test of its absorbency to Iodine solution.