Experiment On Preparation Of Activated Coke For Desulphurization Based On Circulating Fluidized Bed Coal Pyrolysis Semi-coke

Activated coke dry desulphurization technology gets a lot of attention because of less water consumption,no secondary pollution,non-corrosiveness,removal of various pollutants and recycling sulfur resources.Since the performance of activated coke is crucial to this technology,the research on the preparation of activated coke has been a hotspot.Recent years researchers have devoted themselves to the preparation of activated coke by using cheap raw materials and most related researches are about lignite and semi-coke.The coal pyrolysis semi-cokes from circulating fluidized bed of clean power generation technology based on coal staged conversion of Zhejiang University are suitable for the preparation of activated coke because of highly developed initial pore structures.In this paper,this kind of semi-cokes and corresponding coal tar produced by pyrolysis are used as raw materials to the preparation of shaped activated coke and unshaped granular activated coke for desulphurization.One kind of Huaneng Gansu long flame coal semi-coke and two kinds of Pingdingshan inferior bituminous coal semi-cokes are chosen in this paper.Because the high ash contents of the inferior bituminous coal semi-cokes are very unfavorable for the preparation of activated coke,this paper is mainly about the research on the preparation of activated coke by Gansu long flame coal semi-coke.The suitable preparation conditions obtained from the preparation of activated coke by long flame coal semi-coke are applied to the inferior bituminous coal semi-cokes to analysing the feasibility of the preparation of activated coke for desulfurization by the inferior bituminous coal semi-cokes.The main research results are as follows:1.Experiment on the preparation of unshaped granular activated coke for desulfurization:Steam activation is determine to be the proper activation method and the proper activation conditions are:activation temperature of 800?,activation time of 60min and steam flow rate of 0.015g·min-1·g-1.V2O5 is determined to be the proper catalyst for the activated coke for desulfurization and the optimum proportion of V2O5 is 1%.The desulfurization value of activated coke sample increased by about 20%after supporting 1%V2O5.The Abrasion strength of the final activated coke sample is 94.3%which can meet the standard of qualified product of GB/T30202.4-2013.And the desulfurization value is 53.7mg·g-1 which can meet the standard of premium grade product.Under different activation methods,the desulfurization performances of samples are all well consistent with the surface basic groups contents.The desulfurization performances of the samples increase along with the increase of the surface basic groups contents and thus,the surface basic groups contents may be the main factor affecting the desulfurization performances.2.Experiment on the preparation of shaped activated coke for desulfurization:The proper shaping conditions are:coal tar of 30%,carbonization temperature of 600? and carbonization time of 60 min.And the proper activation conditions are:activation temperature of 800?,activation time of 80min and steam flow rate of 0.02g·min-1g·-1.Under the proper preparation conditions,the activation yield,abrasion strength,compressive strength,desulfurization value and desulfurization value after supporting 1%V2O5 of the avtivated coke sample are respectively 62.0%97.5%52.8daN 46.8mg·g-1 and 59.8mg·-1.The abrasion strength,compressive strength and desulfurization value of the sample can meet the standard of premium grade product.Desulfurization performances of samples show a significant positive correlation with specific surface area,microporous pore volume and total pore volume.At the same time,the surface basic groups contents also have a significant effect on the desulfurization value and the increase of the surface basic groups contents is beneficial to the desulfurization performances.3.Experiment on the regeneration of activated cokes:Considering the factors of energy consumption,carbon loss and desorption effcts,the proper generation conditions are:desorption temperature of 350? and desorption time of about 30min.After continuous desulfurization and regeneration,the surface basic groups and acidic groups contents of samples respectively decreased and increased significantly.Both of the decrease of basic groups and increase of acidic groups are not beneficial to the desulfurization performances.Therefore,the decrease of basic groups and increase of acidic groups may be the main reason for the decrease of the desulfurization performances of activated coke samples with the increase of the regeneration times.4.Experiment on the preparation of activated coke for desulfurization based on inferior bituminous coal semi-cokes:After steam activation and supporting 1%V2O5,the desulfurization values of the unshaped granular activated coke samples prepared based on the two kinds of inferior bituminous coal semi-cokes increase dramatically.The desulfurization values can meet the standard of the first-class or even the premium grade product.However the abrasion strengths of samples cannot meet the standard of qualified product.Therefore the feasibility of the preparation of unshaped granular activated coke for desulfurization based on inferior bituminous coal semi-cokes is low.After carbonization,steam activation and supporting 1%V2O5,the abrasion strengths of the shaped activated cokes prepared based on the two kinds of inferior bituminous coal semi-cokes are extremely high which can meet the standard of the premium grade product.Besides the desulfurization values increase dramatically which can also meet the standard of the premium grade product.Therefore the preparation of shaped activated cokes for desulfurization based on inferior bituminous coal semi-cokes is feasible.However the desulfurization values of the activated coke samples prepared based on inferior bituminous coal semi-cokes are approximately only a third to the samples prepared based on the long flame coal semi-coke.This means that under the same preparation cost,the profit of the preparation of activated coke based on the inferior bituminous coal semi-cokes is far lower than that of the long flame coal semi-coke.And thus the selection of raw semi-coke is crucial to preparation of activated coke.The experiments show that the semi-cokes with low ash content,more surface basic groups contents and good initial desulfurization performance should be selected as the raw materials for the preparation of activated coke for desulfurization.