The production process of the Willem Alexander power plant in Buggenum is extremely advanced.
The gasification of coal and biomass produces a combustible gas. This gas is 60% CO (carbon monoxide), 30% H2 (hydrogen) and the remainder is comprised of nitrogen, water vapour and some pollutants. The combustible gas is then purified and burned in the gas turbine. The heat generated during this process is used to propel the turbines in the power plant, which produce electricity via the generator (a very large dynamo).
Explanation of the production process
Coal is transported from our harbour and loaded into the equipment. There it is pulverised and dried to create powdered coal. The powdered coal is stored under nitrogen and pressurised and transported using nitrogen.
Coal gas is created in the gasifier by adding oxygen to the coal and bringing the mixture to a high temperature under high pressure. The fraction of the coal that is not combustible (rock) solidifies and is expelled as slag. The coal gas consists primarily of carbon monoxide and hydrogen and at this stage still contains various contaminants. These contaminants are removed in a series of steps. The non-combustible parts of the coal come out of the gasifier in the form of slag. The coal gas is combustible and toxic. It is cooled in the syngas cooler. The heat emitted in this process is converted into steam.
Next, the fly ash, fine particles that contain non-combustible bits of the coal, is removed in two steps.
Subsequently the gas is washed with water. Water-soluble compounds such as chlorides and fluorides are extracted from the coal gas. The water used in this process is purified in the waste water treatment system and then reused.
During the following desulphurisation, Hydrogen sulphide (H2S) is extracted from the coal gas. About 99% of the sulphur from the coal combines to form pure sulphur. This is reused in the chemical industry. A tiny fraction of the sulphur goes into the restgas incinerator as sulphur dioxide (SO2) and is emitted into the air.
The purified coal gas is diluted with nitrogen in the saturator and saturated with water vapour in order to reach low NOx emissions. It then goes to the gas turbine. Here the coal gas is burned, turning the gas turbine. The hot exhaust gasses emitted from the gas turbine are cooled in the heat recovery boiler. The heat released is converted to steam, which turns the steam turbine. The electricity is ultimately produced by the generator turned by the combined force of the steam and gas turbines.
In the air separation system we produce oxygen and nitrogen from the air at very low temperatures. As already described, these gasses are used in the gasification process.
The entire facility can be seen as the gas factory on the one hand, where the gas is created and cleaned, and as the electricity generation plant on the other, where the gas is used. If the gas factory produces more gas than the generation plant can use, the extra gas is burned using the flare.