Ghanaian tanker drivers blame high propane content in LPG as cause of recent explosions [Updated]
17 October 2017
According to GhanaWeb, the Association of Liquefied Petroleum Gas (LPG) Truck Drivers is blaming the high propane content in gas from the Atuabo processing plant as the cause of recent gas explosions during discharge at filling stations in the country. The most recent explosion, at Atomic Junction in a suburb of Accra on October 7, killed seven and injured at least 132.
The association says that because of the high propane content in the LPG from Atuabo, the pressure of gas from Atuabo is far higher than imported LPG. This destroys vital components in the trucks and at the filling stations, resulting in leakages and the resultant fires.
In Ghana, imported LPG is a mixture of 20% propane and 80% butane. But the propane level in gas from Atuabo ranges between 50% and 70%, according to GhanaWeb.
Speaking to The Finder, Shafiu Mohammed, Chairman of LPG Truck Drivers Association, said high pressure due to high propane content destroys their discharging pumps and hoses when they load gas from Atuabo. In addition, he said, safety valves on the trucks are also damaged by the pressure of gas from Atuabo.
He said that LPG with high butane content is less likely to cause explosions because during leakage, the gas gets frosted to form an ice-like residue due to the high liquid levels, rather than escaping into the air like propane.
He also revealed that the gas from the Atuabo processing plant does not have the odour of imported LPG, which, he said, poses a clear danger as a leak cannot be smelled.
Mohammed explained that the gas explosions at Dansoman and Atomic Junction were both caused by gas from Atuabo. The explosions at the Trade Fair site and Takoradi were caused by imported gas, but with a similar chemistry to Atuabo gas, he said.
Mohammed is convinced that until the propane levels in gas from Atuabo is reduced to the Ghana standard of around 20%, gas explosions are likely to happen again.
Update: On October 19, NewsGhana said the CEO of the company that owns the Atuabo Gas Processing Plant refuted the claims made earlier by the LPG Truck Drivers Association.
Dr. Ben Asante of the Ghana Gas Company denied that the gas produced at the plant was of low quality and posed a higher risk of explosion than other sources, and might have been responsible for the Atomic Junction gas explosion.
At a press conference in in Accra, Asante said the pressure of LPG from Atuabo was slightly higher than that produced by the Tema Oil Refinery and imported LPG because of its higher butane content, but that it fully met the Ghana Standards Authority’s requirements and did not pose any risk. The GSA vapour pressure limit is 9 bar, against 7.5 bar for Atuabo gas.
He said that atmospheric heat in Ghana can increase vapour pressure of LPG by a maximum of 1 bar, and that the safety valves on gas infrastructure have been designed to automatically open to reduce the vapour pressure to the required levels.
He explained that the source of the gas determines the propane content, saying LPG from raw wet natural gas has higher propane content while LPG derived from the processing of crude oil at refineries has lower propane content.
Asante also said that Ghana Gas used Quantum Terminals to odourise its gas, contradicting a central claim by the LPG Truck Drivers Association that Atuabo gas was odourless.
He said there had been an attitudinal change towards safety and the environment by handlers and users of LPG in the country, but that more work needed to be done to enforce standards across the supply chain, including periodic safety audits.