Abstract
The paper presents a Process Integration application for waste heat utilisation from exhaust gas streams with partial condensation. It is based on the hot composite curve construction representing the gaseous mixture cooling with accounting for the condensable vapour part's gas–liquid equilibrium. With cold composite curve for streams requiring heating, the Pinch Point is determined. On this basis, the heat exchanger network (HEN) structure for utilised heat integration into the factory's energy system is developed. It accounts for the possible splitting of two-phase flow on gas and liquid streams and plate heat exchanger (PHE) type selection for specific positions in HEN. The method is illustrated by a case study of heat utilisation from exhaust gases after superheated steam tobacco drying and flue gases from natural gas-fired boiler. Heat transfer areas of PHEs in HEN are optimised with the total annualised cost as an objective function. The received solution's payback period is less than four months, with a substantial saving of energy, up to 10.9 TJ/y. It also leads to the reduction of CO2 emissions up to 600 t/y. About 3830 t/y of steam is not discharged to the atmosphere and as the water returned to the production process. To manuscript “Integration of Low-Grade Heat from Exhaust Gases into Energy System of the Enterprise”
Highlights
The sustainable development of mankind is characterised by a growing need for energy
According to the analysis presented in paper by Papapetrou et al (2018), the potential of waste heat available in EU only is up to 300 TWh/y, with 33% of low-grade heat at temperatures below 200 °C and 25% with temperatures 200-500 °C and the rest at below 1,000 °C
The efficient utilisation of this heat and its integration into the existing energy system of the enterprise is possible with the application of Process Integration methodology and the use of compact plate heat exchangers with enhanced heat transfer
Summary
The sustainable development of mankind is characterised by a growing need for energy. This paper is implementing the Process Integration method (Klemeš et al 2018) to find an efficient solution for utilisation of waste sensible and latent heat from exhaust gases with the use of recuperative heat exchangers. It accounts for the nonlinear character of enthalpy and heat capacity flowrate dependence from the temperature in gaseous mixture streams with partial condensation of one of its component. The utilisation of heat is performed with the use of PHEs of specific types appropriate to each position of their application in the heat exchanger network
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
