Preparation Of Petroleum Coke Based Activated Carbons Using KOH As Activating Agent

Activated carbons with advantage of developed pore structure, high specific surface area and huge adsorption properties have been used in many fields, such as gas storage, transportation and enrichment, liquid purify, super electrical condenser, catalytic agent and supporter of catalytic agent. It is common way to prepare activated carbons using base in which KOH is common agent, but the problem’adhere to the wall’would affect the process seriously. To solve the problem existed in the process, the paper divided activation process into two parts, low temperature activation and high temperature activation, and investigated both parts deeply.Activated carbons were prepared from petroleum coke (PC) with different sulphur content using KOH as activating agent. Three different elevating temperature models were designed to investigate if the problem’adhere to the wall’exist after three elevating temperature models and the influence between elevating temperature model and the pore structure of the product after low temperature activation (PAC). We found that the problem ’adhere to the wall’was solved after low temperature activation and the paper also supposed a relationship between three elevating temperature models and pore structure. Combined with the effect between activation temperature and pore structure, we confirmed the hypothesis above. At the same time different factors, such as ratio of KOH to PC, mixed mode, the difference of Sulphur content (PC with high Sulphur content remember to HSPC and low content to LSPC) were inspected to find out the influence on the pore structure of products prepared during low temperature. Experiments showed that all parameters mentioned above impair the pore structure of the products prepared in low temperature under N2 atmosphere. It has been found that as the weight rate of KOH/LSPC is 2:1 mixing with wet method, the low temperature is 600℃ and hold 1h, PAC with high surface area (SBET) of 1520 m2/g, total pore volume (Vt) of 0.51cm3/g and micropore volume (Vmicro) could be obtained. The low temperature process realizes the purpose of developing pore structure, and micropore structure is the major part.Investigating the influence of elevating temperature models on pore structure of product, we found that the product after high temperature activation would acquire abundant pore structure. The pore structure was different under different elevating temperature models. The elements activation temperature and residence time could adjust the distribution of pore size. Combined with the difference of mixing methods, one-step method and two-step method were investigated. The results showed than the effect in suit was really existed in the process and there would be favourable effect using K2CO3 for activating material with some pore structure. The paper also supposed a method to recycle K2CO3 produced in the process.It has been found that as LSPC as material, the ratio of elevating temperature is 6, the activated temperature is 850℃ and hold 1h, activated carbons (AC)with high surface area (SBET) of 2591.37 m2/g, total pore volume (Vt) of 1.70 cm3/g and micropore volume (Vmicro) is 1.09 cm3/g could be obtained. The pore texture obtained after high temperature was bigger than that after low temperature and micropore structure is the major part.