Experimental Studies On Co-gasification Characteristics Of Petroleum Coke And Moso Bamboo/Sludge

Petroleum coke(petcoke)is the main by-product of the deep thermal cracking process of heavy crude oil,and the yield of petcoke has been increasing year by year.Petcoke gasification is an efficient and clean way for resource utilization,which has broad industrial application prospects.The unique graphitization structure and chemical characteristics are the main reasons for the low reactivity of petcoke.In view of the core issue,this article has carried out a systematic study on the influencing factors and evolution laws of reactivity and syngas quality from two aspects of intrinsic minerals and extrinsic fuel blending.Steam gasification experiments of three different types of petcoke at 1000°C were accomplished in a laboratory-scale fixed-bed reactor.Sequential extraction was applied to obtain the occurrence modes of Ni and V.The mineral occurrence modes was related to the gasification reactivity,syngas quality and coke structure.Results indicate that marine petcoke shows better reactivity than continental petcoke.Ni and V associated with the exchangeable form strongly promotes gasification reactivity.The exchangeable form and Fe-Mn oxides can increase the yield of syngas,while the carbonates and organic matters exhibit the opposite effect.The exchangeable form catalyzes the gasification process by accelerating the development of orderly structure in petcoke during gasification.Ni and V dominated by exchangeable form and Fe-Mn oxides can promote the pore structure formation on the petcoke surface.In order to further improve the gasification reactivity of petcoke,the CO₂gasification experiments of petcoke and moso bamboo/sludge were carried out on a thermogravimetric analyzer.The results show that the addition of bamboo is beneficial to increase the active sites and reduce the mass transfer resistance.A large amount of alkali metal elements in the ash shows a strong catalytic effect to the co-gasification.The best effect is achieved when the mixture ratio of petcoke and bamboo was 1:1.However,during the co-gasification process of petcoke and sludge,the inhibition caused by high ash content is stronger than the promotion caused by high alkali metal content,according to obvious antagonistic effect in the gasification stage,which is weakened with the decrease of petcoke ratio.Finally,the steam co-gasification experiments of petcoke and moso bamboo/sludge were carried out in a fixed bed reactor,and the influence of mixing ratio and addition method of bamboo and sludge on reactivity and gas product characteristics were studied.The impact of synergy.The results show that bamboo and sludge have catalytic effects on the reactivity and gas products.The total amount of syngas reaches the maximum when the blending ratio is 1:1,meanwhile,the LHV is 12.01 MJ/Nm³ and 11.81 MJ/Nm³,respectively.The promotion effect of bamboo is stronger than that of sludge,which is mainly due to the high content of catalytic alkali metal in the ash.In the co-gasification of petcoke and deliming bamboo/sludge,the synergistic effect of reactivity is not obvious.Deliming sludge can significantly promote gas yield,especially when the blending ratio is 25%,the gas yield exceeds the theoretical value of 95.81%.The alkali metals in bamboo ash and sludge ash have catalytic effect on petcoke gasification.A small amount of ash is beneficial to increase gas yield,but a large amount of ash is not conducive to reactivity.