Minimizing energy consumption in industries by cascade use of waste energy

This paper discusses the regional energy saving potential by cascade use of waste heat in energy intensive industries, taking into account the actual local industrial structure in Japan. Energy flow in the industrial combinat composed of iron and steel, cement, paper and pulp and ethylene was optimized to minimize the oil consumption of steam boilers. The simulation results reveals that the local industrial structure highly influences on the energy saving potential by heat cascading. The industrial structure optimizing energy consumption was determined in consideration of spatial constraints of manufacturing plants or heat transmission loss between different plants. More than 90% reduction in oil consumption was expected by interconnection of waste heat supply and energy demand mainly between ethylene and paper and pulp industries.