The Potential of Vapor Compression Heat Pumps Supplying Process Heat between 100 and 200 °C in the Chemical Industry

Abstract

The supply of process heat in the chemical industry is dominated by fossil fuel combustion. Heat with temperatures up to 200 °C could, however, be supplied by vapor compression heat pumps (VCHPs), allowing for efficient electrification. However, there are still several barriers that need to be overcome before they can be widely implemented. In this work VCHPs are thermodynamically compared to heat-driven heat pumps and heat transformers, exploiting the potential of VCHPs. Moreover, steam production, distillation and drying are found to be of primary interest within the chemical industry, and potential integration points are presented and discussed for these applications. Finally, a financial analysis is performed based on a steam production and a superheated steam drying case study. The analysis calculates the levelized cost of heat (LCOH) of a VCHP, heat transformer, natural gas boiler and electric boiler. Furthermore, a sensitivity analysis of the LCOH to the annual operating hours, carbon pricing and waste heat availability is presented. Generally, when no emissions trading scheme (ETS) is applied, both the VCHP and a combination of a heat transformer with auxiliary natural gas boiler appeared as the most optimal solutions, depending on the energy prices. Due to the limited utilization of waste heat by the heat transformer, an auxiliary natural gas or electric boiler is essential to fully meet the required heating load. When an ETS is being applied the VCHP generally appeared to be most financially attractive technology for both the case studies.