Lamma Power Station has an installed capacity of 3,420MW comprising 3x250MW and 5x350MW coal-fire units, 1x365MW oil-fired combined cycle unit, 1x55MW and 4x125MW oil-fired open cycle gas-turbine units. The latest three 350MW coal-fired units, Units L6, L7 & L8, are equipped with FGD plants. The proposed retrofit project will include the installation of FGD plants with flue gas desulphurization efficiency of 90% for the two 350MW coal-fired Units L4 & L5 to reduce the overall SO2 emissions from Lamma Power Station.
At present, the flue gas from Units 4&5 Boilers is directly discharged to the atmosphere via a 210 m high chimney. The retrofit work will involve demolishing the existing Nos. 4 & 5 Light Oil Tanks (each of 250m3 capacity) and relocating some of the pipeworks located in front of the respective boiler to provide areas for installing FGD plant for each of Units L4 & L5. Figures 2.1 & 2.2 show the location and the schematic of the proposed FGD plants.
The flue gas from the boiler will be directed to the FGD absorber inside which removal of SO2 will take place by reaction with limestone slurry. After passing through the absorber, the treated flue gas will be heated up by a gas-gas heater to over 80ºC at boiler rated capacity and directed back to the existing chimney for discharge to the atmosphere.
As majority of the existing common limestone powder/gypsum handling and storage facilities for Units L6, L7 & L8 FGD plants have spare capacity to cater for two more FGD units, the additional equipment required for Units L4 & L5 FGD retrofits will be limited to the extension of the existing gypsum dewatering system.
The equipment to be installed for the proposed retrofit project for Units L4 and L5 includes:
· Two sets of FGD absorbers and associated ductworks
· Two sets of booster fans
· Two sets of gas-gas heaters
· Gypsum dewatering system comprising two sets of hydrocyclones and belt filters
The targeted key dates for the proposed FGD retrofit project are as follows:
· Commencement of demolition of Light Oil Tanks April 2006
· Commencement of civil works September 2006
· Commencement of plant erection for L5 Unit October 2007
· Commencement of plant erection for L4 Unit August 2008
· Commercial operation of L5 FGD Plant July 2009
· Commercial operation of L4 FGD Plant April 2010