On Wednesday 11 March 2015, the first of a total of three 50-tonne distillation towers was lifted into place by two huge mobile cranes at DONG Energy's oil terminal in Fredericia. The distillation towers will ensure that the separated gas, primarily from the Hejre field, meets the sales requirements.
Lars Bach, Director at DONG Energy, said:
"Now, the plant is really beginning to take shape, and the distillation towers are an important part of the core of the new gas treatment where in future, we'll refine the gas extracted from the oil coming from the Hejre field in particular.
Later the same day, the second of the three towers was installed. The towers are placed between the new boiler (left) and the existing degasification tank (right).
The process
As the crude oil from the Hejre field is expected to have a higher content of light hydrocarbons compared to the crude oil from the existing producers (DUC), it is necessary to degas the oil to ensure that it is stable enough to be stored.
This is done by heating up the oil to approximately 55-70°C to separate the gas from the crude oil and thereby stabilising the crude oil. The extracted gas is processed in a gas fractionation facility which, among other things, will consist of two parallel two-stage compressors. Then the gas is transported through three fractionation towers in which the gas is divided into the sales gases, propane and butane, and the 'fuel gas' consisting of ethane and methane. The 'fuel gas' does not meet the sales specifications but will be part of the processes and used to preheat the crude oil from the North Sea.
