Power Plant Gas Feed Modifications

Confidential Client Jessup, PA



The Lackawanna Energy Center is a large (1480 MW) Co-Generation plant in Lackawanna County, Pennsylvania. The plant utilizes natural gas that is dry filtered, measured and regulated on site. This station provides fuel gas for three large gas turbines that are part of a combined cycle system, which also involves steam generation and steam turbine generators.

Plant startup and certain operating conditions were hampered by contaminants of dirt and debris in the gas stream that affected valves and one flow meter. The plant also experienced several over pressurization occurrences resulting from insufficient control valve reaction time during turbine shut-down scenarios. The existing station did not utilize a worker/monitor regulation design, leading the station to rely entirely on a single, full station, pressure relief valve. This condition provided for excessive pressure relief activations during sudden turbine shut-down scenarios, causing gas loss and the destruction of the station relief due to chatter upon OPP scenarios.

Solution Details
design highlights
  • Phased Construction Design
  • Replacement & Upgraded Vertical Filter Separators
  • Retrofit Low-Flow Coriolis Flow Meter Design
  • Enhanced Worker/Monitor Control Valve Design
  • Back-up Station Pressure Relief Valve
  • Dual Station Over Pressurization Protection, OPP
  • Operator Access and Egress Platforms
  • Maintenance Platform Design
  • Structural Design for Pressure Relief Thrust Support

Entech provided design services to address fuel gas and regulation issues, consisting of gas contaminant issues and related impacts on the gate station operation. The basis of design incorporated equipment changes for the following:

Filtration – The existing dry filters were not sufficient for the plant’s gas supply, controls, and gas turbine equipment. Entech revised the piping and supports to retrofit and upgrade the station with two new vertical filter separators to handle the working conditions for the plant.

Gas Metering – The station was experiencing performance issues and clogging of the 2-inch rotary meter during low-flow generation shut-down periods. These issues provided for flow disruption and unaccounted for gas usage. Entech provided piping modifications to allow for a retrofit of a new Coriolis meter, in accordance with AGA-11 guidelines, to provide more precise measurement during low-flow plant shut-down periods.

Control Valves, Pressure Relief & Access - Entech executed a two-phase design to allow for the installation of work/ monitor control valve trains as well as a back-up full station relief valve. The two-phase approach focused on minimizing plant outages, allowing construction to occur during planned plant maintenance events. The new design provided dual OPP of the station along with a back-up relief valve for added protection during maintenance of the primary station relief. Entech also provided maintenance/operator access platforms relief thrust support and foundation design for a new regulation building to enhance the station for worker safety.

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1480 MW Cogeneration Plant

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