Studies On Physico-chemical Properties And Catalytic Gasification Characteristics Of Petroleum Coke

Petroleum coke is the by-product of crude oil delayed coking unit, and gasification technology can realize its efficient and clean use. However, the gasification activity of petroleum coke is extremely low, which greatly restricts the applicability of petroleum coke as the feedstock of gasifiers. Therefore, it is very important to investigate the physico-chemical properties and gasification characteristics of petroleum coke and to find out main reasons leading to the low gasification activity of petroleum coke. Catalytic gasification technology can effectively improve the gasification activity of petroleum coke, and establish a accurate and universal catalytic gasification kinetic model for solving the reality problems of catalytic gasification of petroleum coke, such as the design and optimization of the gasifiers, is of great significance. The main contents and results of this study were summarized as follows.Three kinds of Liquid-Phase Carbonization Cokes (LPCCs) were separately prepared from vacuum residue, coal tar pitch and biomass tar pitch at the pyrolysis temperatures of350～500℃, and the physico-chemical properties and gasification characteristics of LPCCs were investigated. Furthermore, the effects of high temperature calcination on the physico-chemical properties and gasification characteristics of LPCCs were also investigated. The following results were obtained.①A large number of CS2-soluble fraction existed in LPCCs (as high as14.12～66.69%), although the carbon crystalline structures of LPCCs after extraction were almost unchanged, the BET surface areas and total pore volumes of extracted LPCCs increased significantly, which resulted in a greatly increasing gasification activity of LPCCs;②The soluble fractions contained in LPCCs were the most important factor of affecting on the gasification activity of LPCCs;③The ordering of carbon microcrystalline structures of the high temperature calcined cokes from three LPCCs was as follows:coal pitch coke>petroleum coke>biomass pitch coke, while the ordering of gasification activities of the three high temperature calcined cokes was completely opposite.The physico-chemical properties of five coal gasification slag, such as chemical composition, surface morphologies, particle size distribution,and so on,were investigated, and the effects of coal gasification slag on the CO2and steam gasification of petroleum coke were studied. The following results were obtained.①The composition of coal gasification slag is very uneven, the chemical composition of coal gasification slag of different particle sizes are very different, that means the classification and utilization of coal gasification slag can realized through screening process;②The ordering of carbon microcrystalline structures among the different types of residual carbon from coal gasification slag and their rapid pyrolysis char was as follows:DSHHZ>DSHFH>SF-RP1400, while the gasification activities of residual carbon are superior to the rapid pyrolysis char;③The ordering of the catalytic action of different coal gasification slag on the CO2gasification reaction was:SHFH≈SHHZ>GTHZB≈GTHZA>LNHZ, and the catalytic action of coal gasification slag is approximately linear with the Fe2O3+CaO and Fe2O3+CaO+Na2O+K2O contents.The effects of gasification temperatures and loading contents of coal on the gasification activity, gas yields and H2production characteristics of petroleum coke and coal co-gasification processes were investigated. The following results were obtained.￤ith the increasing loading contents of Shenfu coal, the H2yields and total yields of gaseous products from co-gasification increased, and the H2contents increased from51.88%to62.05%;②The ordering of co-gasification reactivity of petroleum coke with coals of different ranks was as follows:XLT>SF>GP; The water-gas shift reactions did not reach equilibrium during the co-gasification of petroleum coke with coals of different ranks, and the extent of the water-gas shift reaction was:XLT>SF>GP;③Coal and petroleum coke co-gasification, especially lignite and petroleum coke co-gasification technology can realize the efficient and clean use of petroleum coke.The effects of composition of gasifying agent and gasification temperature on the non-catalytic and catalytic gasification characteristics of petroleum coke gasified in steam and CO2mixed atmosphere were investigated.①The H2+CO yields and H2/CO ratio in gaseous products from the catalytic gasification are larger than those of non-catalytic gasification;②A single-step to control the composition of synthesis gas with desirable H2/CO ratio to produce the feed gas of FT synthesis reaction from catalytic gasification of petroleum coke in steam and CO2mixed environment is feasible.The CO2catalytic gasification characteristics of petroleum coke catalyzed by different catalysts at the gasification temperature of900℃were investigated,and a universal catalytic gasification kinetic model were established.①The extended random pore model (ERPM) proposed in this paper can not only explain the catalytic gasification characteristics of various metal salts, but also can explain the catalytic gasification characteristics of composite metal salts, even disposable catalysts;②The value of parameters α and β in proposed ERPM can characterization the catalytic ability of catalysts to a certain extent.