According to the report named Post-evaluation by Case Study of Various Technical Solutions to Biomass (crop straw) Power Generation in Jiangsu, two models of co-combustion are introduced in the book. They are Fengxian XinYuan Biomass CHP Thermo Power Co., Ltd and Baoying Xiexin Biomass Power Co., Ltd.

Fengxian XinYuan Biomass CHP Thermo Power Co., Ltd in Xuzhou, was put into operation in 2003. The total investment of the project is 250 million Yuan, of which registered capital is 66 millionYuan. The project construction started in March 18, 2003. Scale in stage 1 covers an area of 220 mu (1 mu = 614 m2), using three 75 t/h sub-high temperature and sub-high pressure circulat­ing fluidized bed boilers produced by Jinan boiler factory and two 15 MW extraction condensing turbo generator units and related auxiliary equipments produced by Nanjing turbine factories, in which units 1 and 2 respectively went into operation in October 17, 2003 and November 26, 2003 in way of co-generation.

Fengxian XinYuan uses two different kinds of fuels, biomass (renewable) and coal (non­renewable). Types of coal include coal, coal gangue and slime and so on. Biomass is mainly from rice husk, loose sawdust and compression molding sawdust. In addition, crushed poplar branches, fruit tree branches (Fengxian is rich in fruits such as apples and peaches), bark as well as forestry residues also can be used.

At present, the mixing ratio of biomass is approximately 20% (mass ratio) in this plant, where coal is still the main fuel. The co-combustion model establishes a good foundation for steady operation and reduces the risk of discontinuous supply of biomass fuels.

Biomass mixed to burn in Fengxian XinYuan is mainly rice husk and sawdust, which are particle fuels and can be directly put into furnace without pre-treatment.

The feeding process of the case is as follows: Biomass is delivered to the hopper first, then transported into the pipeline from the bottom of the hopper and next sent to the biomass and coal mixture room by “V”-shaped belt conveyor. The coal is from pipelines in the vertical direction of the biomass transportation pipeline. After mixing in the hopper, coal and biomass fall on the belt conveyor and then are sent to the storage bin and furnace.

The power plant adopts Combined Heat and Power (CHP) and supply heating mainly, power secondly, which is a thermal power plant of half-public welfare. Heat output of the plant in 2006 is

289,0 tonnes, which is mainly supplied to 15 to 16 enterprises of the industrial park in Fengxian, with price of steam 110 Yuan per tonne on average. The total generation capacity is 210 million kWh, of which net generation to grid is 189 million kWh (electricity consumption in the plant is 10%).

The mixed ratio of biomass in Fengxian XinYuan is 20% (mass ratio), which fails to meet the requirements of the country about the electricity subsidy enjoyed by co-combustion power

plant (ratio of biomass accounted in total heating value of power generation consumption exceeds 80%), so they are unable to enjoy the subsidy of electricity price which is 0.25 Yuan/kWh.