Liquefied Petroleum Gas (LPG) Storage Tanks Boil-off Gas Generation and Management– Review

Abstract

This study is to review works on Liquefied petroleum gas (LPG) storage tanks, in order to assess boil-off gas generation and management. Liquefied petroleum gas (LPG) is used as fuel in heating appliances, cooking equipment, and vehicles. It also powers many business and agricultural processes. In Nigeria, LPG is becoming more useful, especially now that the government is positioning LPG as an alternative for the eventual replacement of firewood and kerosene as domestic cooking fuel, and also canvassing the use of LPG as vehicle fuel for transportation. These have resulted in the emergence of a lot of LPG skid plants, without proper boil-off gas (BOG) recovery systems, thus raising safety and profitability concerns. The generation of boil-off gas in the storage tank causes losses in the LPG supply chain over time. BOG is the continuously evaporated or boiled LPG vapor that causes the pressure inside the tank to rise due to heat entering the tank during storage and transportation, which may change the quality of LPG over time. This BOG is generated primarily due to heat leakage, resulting from the temperature difference between the ambient air and LPG. BOG generation rate is one of the most important factors for the safety and economic assessment of LPG storage tanks.

Assessment of safety and economic impact of boil-off-gas in LPG storage tanks

“…LPG is stored and transported in steel cylindrical tanks as liquid under sufficiently high pressure [1]. To allow for thermal expansion, these tanks are typically filled to between 80% and 85% of their capacity [2], [3]. The LPG stored in a tank exists in equilibrium between a thermodynamic liquid and vapor.…”