Industry Trends for Advanced Class Gas Turbine Fuel Gas Control

摘要

Today’s combined cycle power plant is required to meet flexibility demands on power production while the industry continues to experience rapid changes in technology. Even with the advent of the digital plant, there are still only a few fundamental elements that can safely control the operation of an Advanced Class Gas Turbine. One of the most critical control elements are the valves. A power project’s costs, controllability and reliability are all impacted by valve technology selections. Almost any valve in a combined cycle power plant has the potential to impact operation and reliability however some of the most severe controllability conditions are found connected to the Gas Turbine in the fuel gas system. The pressure to meet lower emissions while increasing thermal efficiency demands very precise fuel flow control for optimal gas turbine combustion; the power industries expectations have not changed over the past decade of Gas Turbine technology advances but the methods used to provide the necessary degree of fuel flow control have. This paper provides insight into the advantages and disadvantages of the fuel flow control valve technology that has been implemented, past and present, alongside the changes being made to meet today’s Advanced Class Gas Turbine demands. This article will focus on control oil versus electric actuation, traditional valve philosophy versus choked flow control, considerations for higher fuel gas temperatures, and impacts to plant design. For each of these focus areas the matters of most interest are discussed including; maintainability, installed cost versus operating cost, and benefits to the Gas Turbine operation.