Topic: Hybrid Steel Works

Abstract

Japanese steelworks achieve the world’s highest energy efficiency. However, approaches that seek intra-steelworks optimization alone have limitations when further energy conservation is planned. It is thus necessary to establish a system in which energy can be effectively used across all of society.

Hybrid steelworks have functionality that combines steel manufacturing and energy supply, focusing on improving the energy utilization of by-product gas. Considering the case of steelworks performing energy recuperation for society, two effects can be expected:

• 1. If, for example, the power generation efficiency rate at the steelworks can be increased from 37 % (current) to 55 % (future), power generation by coal of 4 % would be realized after meeting the power demand of the steelworks. This created power is equivalent in effect to a reduction of coal consumption by 10 % for coal-fired power generation.

• 2. When the energy recuperated from the steelworks for society is electricity, the power generation cost can be inexpensive relative to coal use for the sole purpose of power generation. This electricity is generated via by-product gas after the coal is used for the reduction of iron ore. In this way, it is possible to reduce electricity costs for society.

In other words, it is possible to achieve simultaneous reduction of CO₂ and societal energy costs. In this manner, a hybrid steelworks is defined as an advanced integrated steelworks that combines the functions of energy supply to society and steel manufacturing, by increasing energy utilization of by-product gas (Nakagawa, J Jpn Soc Energy Res 32(4):1, 2011).