Preparation Of Activated Carbons From Petroleum Coke

Pre-activated products (PAP) were prepared from petroleum coke (PC) from SINOPEC Liaoyang Petrochemical Company with KOH as activating agent. Under certain pre-activated condition, the pre-activated samples of petroleum coke and KOH would not adhere the wall of activation equipment during high temperature activation after pre-activation. Firstly, the effects of different preparation parameters including the ratio of KOH to coke, the pre-activation temperature, the pre-activation time and the heating rate on the porosity development and surface properties of the resulting PAP were investigated on intermittent horizontal tube furnace under the nitrogen flow. It has been found that as the ratio of KOH to coke is2:1, the pre-activation temperature is550℃, the pre-activation time is30min, the particle size of the PC is smaller than150μm, PAP with high surface area of1116m2/g and total pore volume of0.55cm3/g could be obtained. The pre-activation developed the porous structure of the pre-activated products, and micropore structure is the major part. And then, the pre-activation performance of petroleum coke and KOH was carried out in a continuous screw extrusion activation furnace. The effects of pre-activation temperature and pre-activation time on the pore structure and material state of the pre-activated products were investigated in order to achieve the conversion of KOH and transformation of material state to eliminate sticking to the wall in the continuous activation.Based on pre-activation, high specific area activated carbons were prepared from pre-activated products with KOH as activating agent using the two-step activation. The effects of different preparation conditions including the ratio of KOH to PAP, activation time and activation time in the nitrogen on the porosity development and material state were preliminary investigated. The results show that with the ratio of KOH to PAP is5:1, the activation temperature is800℃, the activation time is60min, activated carbon was characterized by high specific surface of3764m2/g, and the total pore volume of2.11cm3/g could be obtained. The mixed materials kept particulate state and didn’t happen melt phenomenon.Activated carbons were applied to the electric double layer capacitor as electrode materials. Under certain scan rate, it was found that the quality of specific capacity of activated carbons prepared from two-step activation and one-step activation via pre-activation were significantly greater than that of the activated carbons one-step activation as electrode material.