Design and partial validation of a system for processing and utilisation of vegetable peels, trimmings and flower waste to be used in iron and steel sector

Abstract

From the earlier days, in the world, Iron and Steel technology is the base of all development and infrastructure build-up, not only in economy, also in the human civilisation and daily life. Demand of this material is increasing with days, due to better properties and longer durability. Although the costing of reducing agent, Metallurgical coke is extremely higher. Coking process of lesser grade coal to produce coking grade coal is time consuming and relatively costlier. Also, the stock of coal and fossil fuel is in severe deterioration. In this situation, to execute the reduction process of iron ore (Hematite, Fe2O3), there is the higher need of alternative source of carbon rich reducing agent. In present day, in India, population is increasing in rapid rate. For this, as the demand of food and flowers is increasing, the amount of vegetable and flower wastes is also enhancing. The dumped peels and trimming of vegetables and flower wastes can be the potential source of carbon. In this context, study has been done on 4 vegetables: Potato, Pumpkin, Potal, Banana and 1 flower: Mary gold. The TGA-DTA analysis expresses that the peels and trimmings of vegetables and flower wastes contain about 85% water molecule as well as 15% pure form of carbon. In this study, from TGA-DTA plot, it is found that heating the vegetable and flower wastes for 30 minute at 350 deg. C, moisture content can be removed to obtain bio-dust containing pure form of carbon. This carbon containing bio-dust for each vegetable and flower is mixed with iron ore in stoichiometric basis, in presence of binding agent to produce nugget. Each of 5 nuggets are heating in raising hearth furnace at 1000 deg. C for 1 hour to reduce iron ore to metallic iron, the sign of reduction can be observed from X Ray Diffraction or XRD plot. Along with this, during heating the waste materials to generate bio-dust, huge amount of moisture can be lost. To prevent this, a design has been provided to condense the steam to get pure form water as well to reheat and pass the steam through the bio-dust at 900 deg. C to produce Syn-gas with the collection of excess steam content in form of water. This Syn gas can enhance extent of reduction by allowing it to pass through pre-reduced ore at 900 to 1000 deg. C. The water is potable and can be applied in laboratory and industrial purposes. The entire study signifies the vegetable (Potato, Potal, Pumpkin, Banana) peels and trimmings and flower wastes as the potential source of pure form of carbon to be applied in reduction in Iron ore (Hematite, Fe2O3), and the optimisation of moisture content released from the waste material to obtain Syn gas and allowing it through pre-reduced ore to enhance extent of reduction as well as the degree of metallisation. Entire values, calculation and plots related to laboratory testing and design is provided in this study.