Chemically activated carbon and methods for preparing same
The invention is directed to a chemically activated carbon, based on a combination of wood particles and comminuted carbonaceous vegetable material selected from kernel or shell material, in a weight ratio of between 5-95 to 90-10, preferably between 15-85 and 90-10, further optionally containing a binder, said carbon having been chemically activated using phosphoric acid or zinc chloride and to a process for producing same.
1. A process for producing chemically activated carbon comprising:
forming a mixture comprising wood particles, comminuted carbonaceous vegetable materials selected from the group consisting of kernel and shell material, and a chemical activating agent selected from the group consisting of phosphoric acid and zinc chloride;
shaping said mixture;
heating the mixture to remove water and other volatile constituents present; and
chemically activating the particles by carbonising the particles,
wherein the chemically activated carbon has a butane working capacity greater than 10.2, and a butane retentivity lower than 7.5 g/100 g of activated carbon.
2. The process of claim 1 , wherein the wood particles are selected from the group consisting of wood chips, saw dust, and wood flour.
3. The process of claim 1 , wherein the vegetable material is selected from the group consisting of nut shell, fruit stone, olive stone, almond shell, and coconut shell.
4. The process of claim 1 , wherein the mixture further comprises a binder.
5. The process of claim 4 , wherein the binder is selected from the group consisting of lignin and a lignin compound.
6. The process of claim 1 , wherein the chemical activating agent is present in the mixture in a weight ratio of between 1.0:1 and 3:1, based on the weight of the wood particles and comminuted carbonaceous vegetable material.
7. The process of claim 1 , wherein the chemical activating agent is phosphoric acid and is present in a weight ratio of between 1.5:1 and 2.2:1, based on the weight of the wood particles and comminuted carbonaceous vegetable material.
8. The process of claim 1 , wherein at most 5 wt. % of the comminuted vegetable material is formed by particles having a diameter of less than 1 μm, and at least 95 wt. % of the comminuted vegetable material is formed by particles having a diameter of less than 750 μm.
9. The process of claim 1 , wherein at most 5 wt. % of the wood particles are formed by particles having a diameter of less than 1 μm, and at least 95 wt. % of the wood particles is formed by particles having a diameter of less than 750 μm.
10. The process of claim 1 , wherein the carbonising is performed at a temperature between 350° C. and 700° C.
11. The process of claim 1 , wherein the heating is performed at a temperature between 50° C. and 200° C.
12. The process of claim 1 , wherein the chemically activated carbon has a butane working capacity from 10.2 to 13.7.