Research On Sliding Pressure Optimization Method Of Steam Turbine Unit Based On The Main Steam Flow

With the rapid development of power industry, large capacity and high parametersturbine unit increasing, the unit often face a peaking run problem, and often work in thecondition of large load change, which is between55%to90%. In order to improve theeconomy of the unit, the unit generally works in the way of sliding pressure operation,but the sliding pressure operation curve which is used nowadays is generally use unitload as the independent variables and determined by a particular heating extraction andbackpressure. So when the heating steam extraction capacity and back pressure ischanged, the original sliding pressure curve is not accurate, and effect the economy ofthe unit.Against thermal power generating sets of sliding pressure curve is not accurate, thisthesis presents and discusses in the method for determining a sliding pressure curve inthe detail which is based on the main steam flow. The advantage of this new method isas:1) The sliding pressure curve which is get by this new method applies to thedifferent conditions which is changed by heating steam extraction capacity andbackpressure, which satisfy the requirements of the different workingconditions as a single sliding pressure operation curve.2) The method which determines the sliding pressure curve t is simple.3) This sliding pressure curve is easily implemented in the DCS.This thesis first analyzes the problem of the currently unit in sliding pressureoperation, from this determined the method to deter the sliding pressure curve whichusing main steam flow as the independent variables. Then to analyze the correctness ofthis method in detail theory from the two angles of the entire thermodynamic processand the Heat Loss Rate calculation. On the basis of this theory, design the scheme onhow to implement experimental program. And apply the experimental program forsliding pressure optimization experiments on Harbin Thermal Power Unit7, calculatedand get the curve of sliding pressure operation which is prospered in this unit. Finally,through the economic comparison before and after reconstruction unit, fully validated the innovation, accuracy and superiority of this method.