Matrix Method Research on the System Utilization of the Shaft Seal Steam Based on the Equivalent Enthalpy Drop Theory

Auxiliary steam, particularly shaft seal steam, is important for partial quantitative analysis of thermal system in power plant. The paper found that: whether at the steam or drain side of the regenerator, the recovering effect of shaft seal steam is equivalent to each other in calculation. Through mathematical derivation, this paper established the matrix for system utilization of shaft seal steam which based on the equivalent enthalpy drop method. The paper calculated the thermal economics of N200-130/535/535 unit by the presented matrix method, and concluded that the calculation results of matrix method is exactly the same as that of the heat balance method. With the matrix, the shaft seal steam should be recovered at the regenerator of high energy level. The matrix method for the partial quantitative analysis and the economy of thermal system is fast and accurate, and helpful to the energy-saving in power plant.