Economic benefits for the metallurgical industry from co-combusting pyrolysis gas from waste

The paper presents some benefits that can be gained in the metallurgical industry from utilizing pyrolysis gas obtained from biomass and plastic waste, in particular in a pusher type reheating furnace. The typical fuel composition that normally involves a mixture of natural gas and coke oven gas was modified by introducing a 9–16 % share of pyrolysis gas. The materials used in the production of the pyrolysis gas were alder and pine chips, as well as polypropene waste. For all these materials, the contents of carbon, hydrogen, nitrogen, sulfur and oxygen were experimentally estimated on a test stand for solid fuel conversion in a stationary bed at the temperature of 600 °C. The design capacity of the furnace was 90 t/h and the installed power of the furnace was 72.3 MW. Based on data gained from the rolling mill of a steel mill located in Poland, analysis of the profitability of using pyrolysis gas for co-combustion with coke oven gas and natural gas in an industrial heating furnace was carried out. As a result, a significant benefit can be achieved, namely reduced production costs of the analyzed steel company by utilizing pyrolysis gas, leading to an increase in the attractiveness of the plant's products. Plastic waste and biomass are employed as energy sources in the suggested technology, therefore using them as feedstock for the pyrolysis reactor combined with the pusher type metallurgical reheating furnace is a potential proposal for the future. •Pyrolytic gas is proposed to be co-combusted in pusher-type heating furnace.•Calorific potential of pyrolytic gas obtained from different wastes is exposed.•Economic benefits of the proposed solution are evaluated.