Thermodynamic analysis of an innovative steam turbine power plant with oxy-methane combustors

The Rankine cycle steam turbine power plants make a base for world electricity production. The efficiency of modern steam turbine units is not higher than 43–45%, which is remarkably lower compared to the combined cycle power plants. However, an increase in steam turbine power plant efficiency could be achieved by the rise of initial cycle parameters up to ultra-supercritical values: 700–780◦C, 30–35 MPa. A prospective steam superheating technology is the oxy-fuel combustion heating in a sidemounted combustor located in the steam pipelines. This paper reviews thermal schemes of steam turbine power plants with one or two side-mounted steam superheaters. An influence of the initial steam parameters on the facility thermal efficiency was identified and primary and secondary superheater parameters were optimized. It was found that the working fluid superheating in the side-mounted oxy-methane combustors leads to an increase of thermal efficiency higher than that with the traditional boiler superheating in the initial temperature ranges of 700–780◦C and 660–780◦C by 0.6% and 1.4%, respectively.