Estratégia de retrofit do refrigerante hcfc-22 em máquinas de refrigeração de uma indústria petroquímica visando a eficiência energética

Abstract

High-level industries are increasingly aware of their environmental impacts, so they require high-performance facilities coupled with the least possible environmental impact. At this juncture refrigeration systems must be adapted to the most modern techniques and performance standards, so that old fluids must be replaced within a strategy that prioritizes performance, cost benefit and the latest environmental issues. This work aims to define a better strategy to be adopted for the retrofit of HCFC-22 refrigerant in cooling machines of a petrochemical industry. The study aims to meet the determinations of the Brazilian Program for HCFCs Elimination that established a gradual restriction of the fluid in the period from 2013 to 2040. In the researches and simulations, it was possible to predict the behavior of two alternative fluids, HFC-134a and HFC-404A, which were selected from criteria that exclude other existent fluids. From the simulations it was possible to determine that HFC-404A as a substitute for HCFC-22 results in a slight drop in efficiency and cooling capacity. The HFC-134a has a better performance in terms of efficiency and since the mass flow rates of the installation are maintained, its cooling capacity is equivalent to the HCFC-22. In terms of environmental evaluation, the HFC-404A does not affect the ozone layer, but presents a high global warming potential when released into the atmosphere and, combined with its lower efficiency, resulted in a higher CO2 equivalent generation. In the case of HFC-134a it does not affect the ozone layer and has a low global warming potential combined with its better efficiency it resulted in lower CO2 equivalent generation. In the economic aspect, the HFC-134a fluid presented results that allow its immediate exchange and the HFC-404A will only present viability as the HCFC-22 use restrictions advance. Finally, the study presents a strategy of retrofit of these machines considering technical, environmental and financial aspects of the change.