A high-efficiency, turnkey wood chip-fired power plant with advanced steam conditions
Fugou power plant is one of the 20 biomass power plants to have been installed by DP CleanTech in China from 2006 to 2009. This 12MWe wood chip-fired power plant in Fugou county of Henan province is operated by DP CleanTech sister’s company National Bio Energy (NBE) along with 10 other wood chip-fired power plants of 12 or 30MWe.
The plant has an installed capacity of 12MWe. It runs mainly on local fuels from agriculture residues such as cotton straw considered as hard fuel and in the form of wood chips. In the wood chip-fired boiler, so called soft fuel such as straws can be fed in up to 35%. The plant consumes more than 50,000 tons of wood per year and reaches an availability of 7800h/y.
The wood chip-fired steam boiler operates with high steam parameters at 92 bar and 540oC resulting in a net overall plant efficiency of more than 33%.
The fuel handling system mainly utilizes wood chips but is flexible and can also utilize auxiliary fuels such as different kinds of straw depending on the availability of the biomass. The storage area has a capacity corresponding to 7 days of consumption at full load.
The wood chip firing system and steam boiler island are based on a Danish technology by Burmeister&Wain Energy (BWE) which has since been adapted and improved by DP CleanTech.
The design of the steam boiler together with the proper selection of materials counteracts the fouling and corrosive effects of the fuel.
The steam boiler is provided with a fabric filter for removal of particulate matters so all emissions are below the limit values stated in the planning permission.
The plant consumes approximately 50,000 tons of wood per year. The wood is supplied by local farmers who deliver the fuel to the logistics stations located around the plant site where the fuel is shredded. The wood chips arrive at the plant on trucks which deliver the fuel to the storage area. The boiler buffer silo has a capacity of approximately one hour of operation. From the silo, the fuel is led to the spreader stokers via dosing screw conveyors. The wood chips are then fed into the boiler at the required flow rate under carefully controlled conditions.
Spreaders blow the wood chips into the furnace and whilst suspended in the air, the combustion of the fuel particles begins. The main combustion process takes place on the water-cooled vibrating grate; the vibrating movements regulate the stages of combustion. Part of the combustion air is fed to the furnace from beneath the grate and further combustion air is led to the furnace through nozzles situated above the grate. The ignition zone of the grate is stabilized by means of a patented ignition air supply system. The vibrating motion occurs in cycles which alternate between 1.5 – 3 minutes for a period of 3 – 5 seconds at a time. The fuel ash and slag are transported down the grate to the slag fall along with the final burn out of the fuel.
The steam boiler is a water tube boiler with hanging superheaters which produce 130 tons of steam per hour at 92 bar and 540oC. The boiler design has been specially developed to work with the high temperature and high pressure. The steam produced is used in a conventional steam cycle turbine. Having been cooled in the boiler, the flue gas is cleaned in a fabric filter before being discharged through the stack.
© Copyright DP CleanTech 2012 Web Design and Development by
PDF