MHPS focuses on increasing biomass cofiring ratios3 July 2018
Mitsubishi Hitachi Power Systems (MHPS) reports it has successfully achieved a wood pellet biomass fuel mixing ratio of 34% (on a heat value basis) at a pulverised-coal-fired power plant in Fukushima prefecture. This is believed to be the first time in Japan that a biomass cofiring ratio of this level, at rated load, has been achieved at a PC fuelled plant of the 100 MWe size class, the company says.
The cofiring test was conducted at the 112 MW Soma Energy Park power plant, recently completed by MHPS for the plant owner/ operator Soma Energy Park LLC.
The biomass cofiring test was launched in January 2018. It was initially confirmed that stable power generation was possible with a 30% (by heat value) biomass mixing ratio, as planned when the facility was designed. The test also demonstrated that a mixing ratio of 34% was achievable at rated load, along with a 50% ratio at partial load. The results showed that, compared with 100% coal firing, use of biomass in the fuel mix enables a reduction in CO2 emissions of over 30%.
In 2014 MHPS was contracted to perform engineering, procurement and construction for the plant, as a member of a consortium that also included MHPS Environmental Solutions and Mitsubishi Electric Corporation. MHPS manufactured and supplied the coal/biomass mixed- combustion boiler, the steam turbine, the flue gas desulphurisation equipment and selective catalytic reduction system.
The boiler is designed to accommodate three different combustion processes. By switching from coal to biomass as the fuel for one of those processes, biomass cofiring is achieved without any major change in equipment, says MHPS.
In addition to the biomass cofiring tests at Soma, combustion tests carried out separately at MHI’s Research & Innovation Center have confirmed that the ratio of biomass can be further increased, up to 100%. As well as application to new boilers, the approach can also be applied to modify existing boilers to enable a high biomass mixing ratio.
In the field of coal fired power generation, in addition to supercritical and ultra-supercritical power generation technologies, MHPS says it is focusing on biomass cofiring and increasing mixing ratios.