Abstract
The industrial sectors are the largest energy consumers of China, accounting for more than 60 % of China’s overall energy consumption. However, a large part of energy in the industrial sector is not used efficiently, and there is great potential for enhancing energy utilization efficiency. This paper is the first work that explicitly addresses the conception of China’s industrial residual energy, which includes the definition, classification and quantification of twelve high-consuming industry sectors in China. Sankey Diagram approach is applied to analyse the current situation of IRE that can intuitively reveal the relations among specific forms and the reason why China has not utilized IRE efficiently, based on which we propose the policy suggestions. The energy flows are illustrated via Sankey Diagrams, which explicitly indicate stages with huge energy waste thus great potential for improving. Results show that the iron and steel sector has the largest potential for energy recovery, amounting to approximately 300 Mt coal equivalent per year. The energy recovery potential in each sector is further divided into three levels according to technical difficulty, namely full potential, technically recoverable (TR), and already utilized. Based on the results, prioritizing development of some energy recovery technologies is proposed, including coke dry quenching, combined cycle power generation from industrial residual gas, and power generation with low temperature waste heat during cement production, with an expected annual energy saving of 120 million tonnes coal equivalent.
