Process integration and opportunities for heat pumps in industrial processes

Process integration methods allow one optimizing industrial processes. The main goals are decreasing energy demand and operating costs as well as reducing pollutants emissions. High fuel costs promote installations of heat pumps. In a heat pump, process waste heat is valorized by electrical power to produce higher quality heat. This energy is used to satisfy a part of the process demand so that less fuel is required and CO2 emission will decrease. Based on pinch analysis, this paper presents a methodology to identify heat pump opportunities in industrial processes. The method considers the whole process including utilities and the energy conversion system. A combined analysis which considers thermal and material streams in the process is realized to optimize the heat recovery and the integration of energy conversion units. By analogy, all water streams are listed and the potential of water recuperation is also calculated. The combination of appropriate refrigeration and heat pump cycles leads to an important energy saving potential. The respective flow rates are defined by optimization. The application case of a typical dairy process is used to calculate the energy and operating cost savings potential as well as its corresponding investment costs and payback rates.