A joint venture of Burns & McDonnell, Skanska and ECCO III, was hired to provide engineer-procure-construct (EPC) services for a lump sum, turnkey project, a 680-MW gas-fired power facility about 75 miles from New York City.
The facility feaures two Siemens SGT6-5000F combustion turbine generators (CTGs), two CMI three-pressure, supplementary-fired heat recovery steam generators (HRSGs) with kettle boiler type rotor air coolers, one Siemens SST5000-KN side exhaust condensing steam turbine generator (STG), a 36-cell air-cooled condenser (ACC) and associated balance-of-plant materials and equipment.
Each gas turbine will be dual-fuel capable, firing pipeline quality natural gas and ultra-low sulfur diesel (ULSD) as a backup fuel. It is designed for cycling load operation. Each CTG is capable of operating at full load in a pseudo simple-cycle mode where steam from the corresponding HRSG bypasses the steam turbine and is dumped to the condenser.
Pre-odorized natural gas is delivered to the site by a new pipeline and is regulated, metered and conditioned on-site. The exhaust of the steam turbine is directed to an ACC. The STG, CTGs and HRSGs are indoors in a common powerhouse building. A maintenance bridge crane facilitates maintenance for both the STG and the CTGs. The heat rejection system uses a 36-cell ACC adjacent to the powerhouse building.
Reclaimed water for the plant is provided from the City of Middletown Sewage Treatment Plant. Makeup water will feed the CTG evaporative coolers, demineralized water treatment equipment, service water, fire protection water and potable water. A demineralization system produces the demineralized water stored in the demineralized water storage tank. Wastewater and sanitary drains (process water, closed cycle cooling water, boiler blowdown and domestic wastes) are discharged to the City of Middletown sewage treatment plant. Stormwater will be collected in a detention pond, with the discharge managed through an outfall structure.
One gas-fired auxiliary boiler produces steam for preheating piping and equipment as required for plant startup and for supplying initial steam to the turbine gland seal steam system. The auxiliary boiler is designed for indoor installation.
Plant synchronization to the 345-kV substation is accomplished through low-side generator breakers for the CTG units and high-voltage generator breakers for the STG.
A plantwide distributed control system (DCS) monitors and controls the balance-of-plant materials and equipment.
Nitrogen oxide (NOx) emissions are controlled by dry low-NOx (DLN) combustors and water injection for fuel oil firing operation. A selective catalytic reduction (SCR) system is included with each HRSG to further reduce the NOx level. Carbon monoxide (CO) and volatile organic compound (VOC) emissions are reduced by an oxidation catalyst in each HRSG.
- Startup and commissioning
- Greenfield site
- Dual-fuel: Natural gas and ULSD
- 2 Siemens SGT6-5000F gas turbines with DLN combustors
- 2 CMI triple-pressure supplementary-fired HRSGs
- 1 Siemens SST5000-KN condensing steam turbine
- 36-cell ACC
- 1 million-gallon fuel oil storage tank
- 1 million-gallon reclaimed water storage tank
- Off-site reclaim water supply line
- 345-kV on-site substation