Coal is the basic reducing agent used in iron making. blast furnace uses coke made from coking coal. dri processes use non coking coal as reducing agent. but the continuous use and exploitation of the coke worldwide has led to doubts rising about the sustainability of blast furnace iron making, propelled by concerns regarding the long-term availability of coke. it is, therefore, universally accepted that the overall competitiveness and sustainability of the blast furnaces and direct reduction plants would depend on the success of lowering the coke consumption by as much as possible. a promising replacement for coke and coal is waste plastics. it can be added to existing reducing systems to improve the efficiency. plastics can acts as solid fuel releasing carbon monoxide and hydrogen along with other gases. nkk keihin works (japan) has successfully demonstrated injection of plastics in blast furnace but similar exercise in solid state reduction is yet to be reported. plastics are non-bio degradable products and most of them are recycled or used for land fill. however, with growing use of plastics in modern appliances the amount of waste will increase manifold. use of plastics in metallurgical industry will be a decisive step in combating the accumulating menace. direct reduction of iron ore is a complex process involving series of reactions. the rate of reaction depends upon the temperature and the reducing system present. the chief reducing agent is co gas. one of the ways to inject hydrogen and carbon monoxide is injection of fuels. they improve the rate but at the same time they are costly. a solution to this problem is the use of plastics. plastics can act as a source of solid fuel supplying hydrogen and carbon monoxide along with other gases. the objective of the project was to conduct a feasibility study of plastic material as a reducing agent. in present work, the iron ore pellets were weighed and their diameters were noted prior to the reduction process. pet was taken from post-consumer soft-drink bottles and cut into small pieces. steel crucibles were used to act as reaction bed. the reduction beds were prepared for each percent-by-weight composition of the coke plastic reductant (0% pet, 5% pet, 10% pet, and 20% pet). the prepared crucibles were then placed into the preheated furnace (temperature varies as 850˚c, 950˚c, 1050˚c). the samples were then preserved at different time intervals and weighed to calculate the reduction percentage. the percentage reduction of iron ore pellets increased with temperature and the reducing system with pet gave higher reduction rate than the reducing system with 100% coke. the sem images were used to validate these findings. the mixture with 5% pet composition showed higher reduction than the other compositions for both coal and coke based systems. this can be explained through the mechanism of pet degradation. initially, the amount of carbon monoxide (co) generated is high as both pet as well as coke is releasing them. along with them, pet also releases hydrogen. gasification rate is very rapid for pet as compared to coke, hence high co potential was developed taking the reaction forward at a quicker pace in the initial phase of the reaction. accretion of pet char in the reaction vessel was observed. it was negligible in 5% but coalesced to large hive like structures in 10% and 20% pet compositions which led to the reduction in permeability. to conclude, pet can be used along with conventional reducing agent thus reducing consumption of these carbon based reductants. better improved extent of reduction was observed in all the pet compositions when compared to 100% coal/coke composition. 5% pet and coke system gave the best extent of reduction. however, accretion and formation of char remain a serious bottleneck in the implementation of process. nevertheless, the work as demonstrated the capability to use plastics in dri production.
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