Simulation and hazard operability analysis of liquefied petroleum gas plant: A case study

Abstract

Liquefied petroleum gas (LPG) is a mixture of hydrocarbons essentially propane and butane. It has recently emerged as a sustainable and alternative fuel source to other conventional fossil fuels in several sectors such as residential, industrial, commercial and transportation. The environmental impact is seen as a positive influence as it reduces black carbon emissions by releasing less greenhouse gases as it undergoes combustion. In this study, a general overview about LPG was offered and the data required for simulating a flowsheet for LPG production was obtained from an LPG plant. Mass balance and energy balance were calculated manually and compared with those of the simulation performed by ASPEN HYSYS 12.0 using Peng-Robinson fluid package. A hazard and operability study for the equipment was carried out as well as their spacing to emphasize their importance on how they shape the safe feasibility of plant construction. It was found that 2209 kg/h of feed gas was mainly converted to 836.90 kg/h of sales gas and 1322 kg/h of LPG. By comparing manual calculations with HYSYS results, the duty for heat exchanger 2 was 55361.17 kJ/h, with error percentage of 3.90%. The sales gas temperature was 318.53 K with 1.42% deviation. Debutanizer condenser and reboiler duties were 892640.20 kJ/h and 746416.30 kJ/h, with deviations of 4.25% and 3.49% respectively. The hazard and operability studies and spacing showed that all the equipment must be positioned at safe distances apart from each other and they require the installation of alarms, sensors, and controllers to ensure a proper and safe production process.