Above all, what affect the ash content of Pet coke are the salinity of crude oil and the degree of desalination. The salinity of cooling water and high pressure water used for decoking also make a difference on ash content, especially the repeatedly used cooling and high pressure water. Besides, if Pet coke is piled up outdoors, the sand on the ground and carried by wind will increase the ash content. In generally, the ash content of the Pet coke which is used for the manufacturing of graphite products should be less than 0.5%, and which is used for high-purity graphite should not be more than 0.15%.
The sulfur content of Pet coke depends on the sulfur content in the residuum. 30%~40% sulfur content of residuum will remain in the Pet coke. Hydrodesulphurization of high-sulfur residuum beforehand can reduce the sulfur content of Pet coke accordingly. Only increasing the calcined temperature to 1450 degree centigrade can show the result of desulphurization.
The volatile matter of Petroleum coke indicates the coking temperature. The temperature is higher, the volatile matter is less. However, it is also related to the reload time of residuum entering into coking tower and condition of blowing vapor into coke bed. Furthermore, coke in the same coking tower has different amount of volatile matter. The coke at higher position in the tower is more porous with more volatile matter. The volatile matter doesn¡¯t influence the quality of carbon products, but makes a difference on calcinations.