Efficiency Enhancement of Gas Turbines - SP1

Research Scientist
930 01 816

SP1 will design Combined Cycles Gas Turbines (CCGTs) where GT exhaust heat runs a Steam Bottoming Cycle (SBC) for additional power generation and increased efficiency. New, compact, and efficient SBC heat exchangers will be key, designed for varying heat transfer and boiling regimes along the heat exchanger tubes.

Control strategies are instrumental for efficient GT and CCGT operation over O&G field lifetime, in interaction with power supply from batteries, wind and high voltage cables. With GTs being able to operate using carbon-free fuels (SP2), CCGTs will play a role when aiming for high energy efficiency.

Objectives:

  1. Enable efficient GT power generation on O&G platforms that operate in an integrated offshore energy system with a high share of renewable energy.
  2. Design compact, efficient, lightweight and reliable GT Steam Bottoming Cycles (SBC) capable of handling the load changes associated with operation in an offshore integrated energy system.
  3. Establish energy-efficient GT+SBC operational strategies for handling rapid load changes, including hot Exhaust Gas Recirculation (EGR), backup batteries, and power from surrounding energy system.

Results 2019

This SP focuses on the design of Combined Cycles Gas Turbines (CCGTs) where the exhaust heat runs a Steam Bottoming Cycle (SBC) for additional power generation and increased efficiency. New, compact, and efficient SBC heat exchangers, designed for varying heat transfer and boiling regimes along the heat exchanger tubes, are essential. Design of efficient CCGTs includes development of effective control strategies for gas turbine and CCGT operation.

Main objective

The main objective is to reduce the emissions related to offshore gas turbine operation. Two approaches are being investigated. The first one is increasing the gas turbine's efficiency during part-load operation. The second approach is to recover heat from the exhaust gas to produce electricity and/or heat in a bottoming cycle.

This concept has been implemented before,  but the large weight and footprint impede widespread implementation. Focus is therefore one developing more compact and lightweight designs, possibly using other working fluid as steam

Main results

  • PhD position announced. Topic: "Assessment of alternative concepts for combined cycle gas turbine operation under varying loads".
  • A report about gas turbine operation and transient behavior was written as basis for future research.
  • A first working fluid screening was performed to compare possible working fluids that can  be used in a bottoming cycle (as alternative to steam).
  • The dynamic modelling and simulation of a combined cycle gas turbine was initialized in cooperation with Siemens.

Impact and innovations

  • More efficient gas turbine operation
  • Compact bottoming cycle designs, possibly with new working fluids, enabling widespread implementation
Early-stage dynamic simulation model of a combined cycle gas turbine in Dymola.