EVALUATION OF ALTERNATIVE REFRIGERANT FOR A 255000 KCAL/HR, 130KW VAPOUR COMPRESSION REFRIGERATION SYSTEM FOR PROPYLENE PURIFICATION PROCESS

Common refrigerants such as CFCs and HCFCs have unfavorable environmental impacts and this has brought about concerns and regulations prohibiting their production and use as refrigerants by the year 2030. The 255000 kCal/h, 130 kW capacity refrigerating system uses R-22 refrigerant which is of the HCFCs' family, hence, the need for alternative refrigerant because of the negative environmental impacts of this family of refrigerants. Natural refrigerants such as hydrocarbons and their mix in various ratios are currently being investigated to replace CFC and HCFC based solvents. In this study, propane (R-290), propylene (R-1270), ammonia (R-717) and ethane (R-170) were evaluated as alternative refrigerants for the 255000 kCal/h Freon (R-22) refrigerating system through modelling and simulation using Aspen Hysys V8.0. Combining energy efficiency, economics, environmental and safety criteria, propane was favoured amongst the studied refrigerants as the choice alternative refrigerant to replace R-22 even though there is need to also replace the existing compressor with a propane compressor because of the extra power of 79.6 kW required to compress propane.