Role of Scrap Recycling for CO 2 Emission Reduction in Steel Plant: A Model Based Approach Manisha Sahoo, Sidhartha Sarkar, Ajoy C. R. Das, Gour Gopal Roy, and Prodip Kumar Sen* Scrap recycling in steel industry plays a crucial role in green technology development by reducing CO 2 emissions. Plant scale predictions on effectiveness of steel scrap recycle have been rarely attempted. A life cycle inventory (LCI)-based methodology for plant CO 2 emissions is developed using process modeling of different primary stages (blast furnace-basic oxygen process (BF-BOF) and directly reduced iron (DRI, coal based) - electric arc furnace (EAF) process with scrap additions). Emission data from primary stages is used for secondary processing stages for predicting the scope of further reduction. Plant emission reduction through scrap recycle has shown that primary stage emission values can decrease to 1.79 kg CO 2 /FU (functional unit) and 2.30 kg CO 2 /FU, respectively, for BF-BOF and DRI-EAF routes, by using 400–420 kg scrap per ton of crude steel. The DRI-EAF route emissions can further decrease if gas-based DRI is used. Secondary processing of scrap has the potential to decrease overall steel industry emissions to 1.16 kg CO 2 /FU. Specific country-based data is processed to estimate net emissions with scrap addition to both primary and secondary stages leading to net emissions of 2.17 kg CO 2 /FU from 2.6 kg CO 2 /FU without scrap addition. 1. Introduction Over the past few decades, there has been an increasing demand for steel due to development in building, construction, and transportation. Several forecasts indicate that the world’s steel consumption will increase by the order of 2500 million tonnes up to the year 2050. [1] The steel industry generates between 7 and 9% of direct emissions from the global use of fossil fuel. [2] In the industry sector, the iron and steel sector has the second-largest energy consumption of all industrial sectors (after chemicals and petrochemicals), accounting for 22% of total industrial energy use and 31% of industrial direct CO 2 emissions in 2012. [3] Reducing greenhouse gas emissions is a global challenge for the steel industry that requires a global solu- tion. Besides improvement of energy efficiency in primary production of steel, promoting recycling of steel scrap has prominently featured for reducing CO 2 emissions and driving the steel industry toward circular economy. Statistical data on scrap recycling rates is available for several countries in the literature [4–7] from which it can be observed that the global recycle content of steel from scrap is not high (35–36%). The necessity of increasing recycle content for enhancing steel indus- try sustainability has been stressed by World Steel Association. [2,8] Possible scenarios on scrap availability and utilization has been the subject of various publications which describe poten- tial techniques available for predictions, such as multi recycling approach, product environmental footprint and mass flow analysis. [9,10] For predictions of mitigation of CO 2 emissions, [10] energy saving potential data base and emission factors have been used on a sectoral basis without supporting process models, but using IPCC database for emission factors. Such studies and other similar studies [11,12] lead to sector-based information on CO 2 mitigation which are often country specific. Plant scale predictions on use of scraps for emission reduction have been rarely attempted. The potential of scrap use for emission reduction purposes for a given plant configuration require use of relevant process models for the plant. Such predictions are likely to promote use of scraps for a given plant configuration. This in turn influences the sectoral average for emission reduction through use of scraps. Life cycle inventory (LCI) for CO 2 emissions has been worked out based on use of process models, primary/secondary processing with/ without scrap, as discussed subsequently in a later section. [8,13– 17] Emission reduction is also promoted by diffusion of energy efficient technologies coupled with scrap availability based on various governmental panel information, [7,11,12] although model- based comparative assessment of use of scrap vis-à-vis use of energy efficient technology has not been made at plant scale. The current paper attempts to examine the aspect of emission reduction through scrap recycle in a plant which requires process modelling of different steps to assess the possible M. Sahoo, Prof. P. K. Sen, Prof. G. G. Roy Department of Metallurgical and Materials Engineering IIT Kharagpur, West Bengal 721302, India S. Sarkar Flat 1406, Tapti Tower, Godrej Prakriti Barrackpore Trunk Road, Sodepur, Kolkata, West Bengal 700115, India A. C. R. Das Ministry of Steel Government of India House No A 38, Ramprastha, Ghaziabad, Uttar Pradesh 201011, India E-mail: prodipksen@outlook.com DOI: 10.1002/srin.201900034 www.steel-research.de FULL PAPER steel research int. 2019, 1900034 © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1900034 (1 of 11)