Energy savings from flash steam recovery: An industrial case study

Abstract

In oil, gas and petrochemical production complexes, steam pressure boosting technology is used to recover low-pressure steam, using both mechanical and thermal solutions to increase energy efficiency. The heat recovery from steam, especially flash steam produced in the return condensate lines, can be considered an economic and attractive solution. In an industrial case study in a gas plant located in the south-west of Iran, the LP condensate returns to the LP condenser waste with a flow rate of 96,000 kg/h and a pressure of 0.45 bar. As a result of the pressure drop, about 6800 kg/h of flash steam is generated. Therefore, in order to recover, the first the return condensate current enters a flash drum to separate the amount of steam produced by the flash operation. In this research, two strategies for increasing the pressure using a steam compressor and an ejector have been investigated. The simulation results show that flash steam recycling using steam compressors and ejectors results in energy saving for the refinery of about one million and USD100k per year, and also about 152 and 137 thousand tons equivalent to carbon dioxide emissions per year are reduced, respectively.

Keywords

• Flash steam
• Return condensate
• Vapour recompression
• Emission reduction