SUPER CRITICAL & ULTRA SUPER CRITICAL
Supercritical & Ultra-supercritical
Supercritical (SC) and ultra-supercritical (USC) power plants operate at temperatures and pressures above the critical point*. This results in higher efficiencies – up to 46% for supercritical and 50% for ultra-supercritical – and lower emissions than traditional coal-fired plant.
Temperatures and pressures for different types of plant using bituminous coal:
Temperature (°C) Pressure (bar)
Subcritical 538 167
Supercritical 540 - 566 250
Ultra-supercritical 580 - 620 270 - 285
One feature helping with the deployment of supercritical power plants is their similarities with conventional power plants. This allows supercritical plants to be constructed and operated without significant retraining, enabling faster deployment.
More than 240 high efficiency ‘supercritical’units are in operation worldwide, including a number in developing countries. China, for example, currently has 22 supercritical units in operation, fuelling almost 14 GW of electricity. There are also 24 ultra-supercritical units operating worldwide, which achieve even higher efficiencies, with units in Denmark, Germany, Japan, the Netherlands, and USA.
Temperatures and pressures above those of ultra-supercritical plant could potentially yield further efficiency improvements, however new materials must be found that are able to handle such extreme operating conditions.
* Critical point describes the temperature and pressure above which the working fluid – in this case water – no longer turns into steam but instead decreases in density when it is heated above 'boiling point'. By eliminating this transition into steam (phase change) the efficiency of the process can be improved.
Supercritical (SC) and ultra-supercritical (USC) power plants operate at temperatures and pressures above the critical point*. This results in higher efficiencies – up to 46% for supercritical and 50% for ultra-supercritical – and lower emissions than traditional coal-fired plant.
Temperatures and pressures for different types of plant using bituminous coal:
Temperature (°C) Pressure (bar)
Subcritical 538 167
Supercritical 540 - 566 250
Ultra-supercritical 580 - 620 270 - 285
One feature helping with the deployment of supercritical power plants is their similarities with conventional power plants. This allows supercritical plants to be constructed and operated without significant retraining, enabling faster deployment.
More than 240 high efficiency ‘supercritical’units are in operation worldwide, including a number in developing countries. China, for example, currently has 22 supercritical units in operation, fuelling almost 14 GW of electricity. There are also 24 ultra-supercritical units operating worldwide, which achieve even higher efficiencies, with units in Denmark, Germany, Japan, the Netherlands, and USA.
Temperatures and pressures above those of ultra-supercritical plant could potentially yield further efficiency improvements, however new materials must be found that are able to handle such extreme operating conditions.
* Critical point describes the temperature and pressure above which the working fluid – in this case water – no longer turns into steam but instead decreases in density when it is heated above 'boiling point'. By eliminating this transition into steam (phase change) the efficiency of the process can be improved.
Comments
Post a Comment