Pechino is taking steps to decrease the environmental impact of its own energy industry, thanks also to Eni’s technology. At Sinopec’s refinery in Maoming, Guangdong, a plant will be built based on the so called “EST” technology. EST stands for “Eni Slurry Technology” and will be used by the Chinese to refine the heavier residues from oil production and turn them into lighter, more valuable products, such as diesel and petrol. The crude oil extracted from the subsoil is a mixture of numerous organic molecules, mainly consisting of carbon and hydrogen: the hydrocarbons. These molecules can vary in size. The lightest is methane, consisting of just one carbon atom, together with four hydrogens but let’s concentrate ourselves on carbons alone, which remain in a gaseous stateand is the main component of natural gas, followed by ethane (slightly less volatile than methane and consisting of two carbon atoms), propane and butane(with three and four carbons) and pentane, with five carbon atoms, which is the first of the hydrocarbons that stays liquid at room temperature.
Heavier molecules consist of increasingly longer carbon atom chains and when we reach a number of twenty (or more ) carbons we obtain solids which at room temperature remain in the same solid state and have to be heated up (in increasing temperatures) to bring them to fluid state. To use crude oil, component molecules need to be separated, based on their different length, exploiting their different boiling points.
Refineries serve this purpose: they are huge distillation plants where the crude oil produced from oil wells is injected into a large vertical column. The column is filled with porous materials that enable the mix of hydrocarbons to move up and down. By heating the base of the column, a part of the crude changes its state to vapour, but going up, gets into contact with colder parts of the column so it condenses and the liquid flows back downwards, starting the cycle up again.