Willem-Alexander Power Plant at Buggenum
In Buggenum, near Roermond in Limburg, lies Nuon’s showpiece: a power station with clean coal technology and a green heart.
Unique technology
In 1989 the former Demkolec (now Nuon) started to design the Limburg gasification installation. Construction work commenced in 1990 and the installation has been in operation since the end of 1993.
These days biomass is also co-gasified on a large scale. This combination is unique in the world. Thanks to the new procedure, Nuon reduces CO2 emissions by no less than 22 per cent or 300,000 tons of CO2 per year. That’s comparable to the emissions from 200,000 passenger cars on an annual basis.
Capacity
The net production capacity of the power station amounts to 253 megawatts, enough to power 400,000 households. When the gasifier is operating at full capacity, the power station consumes about 2,000 tons of coal per day. That is slightly more than one barge load. The coal is shipped from all over the world to Rotterdam or IJmuiden and then transported via the Maas to the power station.
Electricity generation using gasification technology
The coal is first converted into combustible gas, called synthesis gas or syngas for short. This gas is cleaned and desulphurised to a degree of purity comparable to natural gas, after which it is suitable for burning in a STAG (Steam and Gas Turbine), where it is converted into electricity. The combination of coal gasification followed by electricity generation in a STAG is called IGCC.
Advantages of gasification
The big advantage of gasification compared to conventional coal-fired power stations is that it produces much less air pollution. The emissions of particulate matter, sulphur dioxide (SO2), nitrogen oxides (NOx) and metals are vastly reduced because the coal gas is thoroughly cleaned. Also, gasification is much more efficient, which results in less use of coal per kWh electricity and subsequently fewer CO2 emissions. In addition, part of the coal is replaced by biomass, which also limits CO2 emissions. The plant's emissions are well within the permitted standard.
Gasification also creates residues. The non-combustible elements of coal (rock) remain behind in the form of slag and fly ash. The slag and fly ash are removed to be used as building materials. 99% of the sulphur content of the coal is removed and sold to the chemical industry. During the gas purification process, salts and sludge are created as well. The salt is reused and the sludge is stored.
Installation components
The Willem-Alexander Power Plant has various equipment parts, which together ensure the total process of coal gasification. The overview below indicates where the different parts of the plant are located and how each part contributes to the production process.
VGE: On the gasification island coal is transformed into coal gas.
LSI: In the air separation unit, oxygen and nitrogen are created, which are required for the process of coal gasification.
ABI: The waste water treatment installation extracts salts and sludge from the water used in the process.
OZW: In the desulphurising facility, sulphur is extracted from coal gas.
STEG: In the steam and gas turbine, coal gas is converted into electricity.