Application of Multivariable Model Prediction Control to Ultra-supercritical Unit - Intelligent Computing for Sustainable Energy and Environment - page 497

subcritical units, but also the thermal eciency of ultra-supercritical is 4% higher
than that of the supercritical units, as shown in figure 1 (IEA ”Focus on Clean
Coal”, 2006). IGCC technology has promising prospect to improve eciency,
although the problem of high investment caused by relatively complex system
still need to be solved. Ultra-supercritical unit technology has good inheritance
and is easy to be implemented in large-scale. Ultra-supercritical units have good
performance as well as subcritical units in various of the reliability, availabil-
ity, heat mobility and unit life. Among all kinds of clean coal power generation
technology, the combination of ultra-supercritical power-generating technology
and ecient gas purification technology is the most feasible way to realize the
large-scale production of high-ecient and clean power-generating in a short pe-
riod of time. If the proportion of ultra-supercritical units capacity can be raised
to 20% in the following ten years, the average coal consumption rate of fossil
power plants can be reduced about 20g/kWh. It means about 0.36 billion tons
of coal in 10 years, equivalent to 0.2 billion tons of CO2 emission, can be saved
[1]. Therefore, increasing optimization and control level of ultra-supercritical fos-
sil power plants are important aspects in boosting the development of fire coal
power-generating technology.
Fig. 1. Comparison of unit eciency and emissions
2 The Diculties of Ultra-supercritical Fossil Power
Plant Control
The high operating parameters value (pressure and temperature) of
ultra-supercritical units and the once-through boiler that needs extensive pitch