18 May 2017

O.3.7.2 Integration of Heat Pumps in Industrial Processes with Pinch Analysis

The industrial sector consumes a considerable amount of energy. In many countries it is 20% or more of the total
energy use of which a major proportion is used solely for heating leading to the need to improve thermal energy
efficiency. Process integration methods involving thermal systems such as pinch analysis provide ways to reduce
energy use and environmental emissions in the process industry. Using pinch analysis it can be systematically
shown how the heating and cooling demands of a process should be matched in order to improve heat recovery
based on an economic optimum between investment and operating costs. An additional measure to help reduce
energy needs is to use a heat pump. However, the integration of heat pumps in industrial processes is a challenge
as it is difficult to choose which parts of the process should be connected to the heat pump. Pinch analysis
provides a convenient rule to help meet this challenge: A properly integrated heat pump works across the pinch
point, i.e. a heat pump takes heat from below the pinch point, where there is an excess, converts it to a higher
quality and transfers it across the pinch point where there is a heat deficit. The aim of this paper is to present the
methodology of how to properly integrate a heat pump using pinch analysis and to apply the methodology to an
industrial case study. With the correct integration of the heat pump it is shown how the overall process energy
efficiency can be significantly increased though the reduction in the hot and cold utilities resulting in lower
energy COSTs.