September 22, 2009
Over the years, the Rimbey gas plant, Keyera’s largest gas processing facility, has benefited from significant capital investment to increase processing capacity, enhance services, maintain reliability and meet current environmental standards. The size of the facility and the scope of its processing options have allowed Keyera to initiate a number of innovative projects to create incremental value.
In 2007, Keyera embarked on a project to modify the facility to extract approximately 5,000 barrels per day of ethane from the raw gas processed at our Rimbey gas plant. Ethane is a natural gas liquid (NGL) with a chemical formula of C2H6 that is often found in natural gas. Ethane is sometimes left in the natural gas stream when it is delivered to end use industrial or residential markets. When a market demand exists, ethane is removed from the gas stream for use as a feedstock to the petrochemical industry and in enhanced oil recovery projects.
Demand for ethane exists in Alberta to supply the numerous petrochemical facilities in the province. To underpin the project at Rimbey, Keyera secured a long-term sales contract with Dow Chemical Canada ULC, a major petrochemical producer, for the sale of the ethane produced at Rimbey.
Prior to completing the project, a significant portion of the ethane contained in the raw gas at the plant was consumed as fuel gas; that is, the fuel was used to generate the steam that powers the process equipment at the facility. To remove ethane from the gas stream, a process known as fractionation is used. Fractionation facilities at gas plants use basic physics, like pressure and temperature, to control the boiling point in tall towers, known as fractionation towers. The process takes advantage of the fact that, at particular temperatures and pressures, certain substances will vaporize and others will not. When a liquid vaporizes, it turns to gas and separates from the rest of the liquids. When this happens in a fractionation tower, the vapour is removed from the top of the tower, while the remaining liquid is taken from the bottom. Each product (ethane, propane, butane and ethane) in the mixture is separated in this manner, using separate towers referred to as the de-ethanizer tower, de-propanizer tower, etc.
At the Rimbey plant, the ethane extraction project involved modifications to the existing natural gas liquids fractionation process and the installation of new compression equipment. To transport the ethane to an ethane transportation pipeline running through central Alberta, a 32 kilometre pipeline was constructed. The modifications and pipeline were completed in the summer of 2009, and the facility was put into operation in August. Today, the modifications have not only resulted in additional ethane being available to support Alberta’s petrochemical industry, but an additional benefit is the ability to extract additional amounts of propane from the raw gas as well. This increases the efficiency of the plant and provides additional benefits to our producing customers.
To read the October 1, 2009 news release, click here
To learn more about the fractionation process, as well as other aspects of Keyera’s business, please visit our Midstream 101 video.