Method for evaluating performances of condensing steam turbine after high back pressure improvement

Abstract

The invention discloses a method for evaluating performances of a condensing steam turbine after high back pressure improvement. The method comprises the following steps: distributing sufficient pressure, temperature, flow and electric power test points on a thermodynamic system of a turbine unit; stopping heating steam extraction on a low pressure cylinder gap bridge pipe; calculating the main steam flow, the cold reheat steam flow and the reheat steam flow; calculating the low pressure cylinder efficiency of a unit; taking a high back pressure heat supply unit as a pure condensing unit running under a high back pressure working condition, calculating the heat loss efficiency of the unit, and performing the second-type correction on the heat rate; and comparing the heat rate and the lower pressure cylinder efficiency with design values of a manufacture plant, and evaluating the lower pressure cylinder improvement technology and the unit improvement effect. The method disclosed by the invention is easy and feasible.

Description

technical field [0001] The invention relates to a performance evaluation method, in particular to a performance evaluation method of a condensing steam turbine after high back pressure transformation. Background technique [0002] The invention relates to a performance test and evaluation method for a condensing steam turbine operated under a high back pressure condition after the high back pressure heat supply transformation. High back pressure circulating water heating is to increase the pressure of the condenser of the steam turbine unit, that is, to reduce the vacuum degree of the condenser and increase the temperature of the cooling water, so that the condenser becomes a heat network heater of the heating system, and the cooling water is directly used It is used as circulating water in the heating network to supply heat to the outside. The high back pressure circulating water heat supply makes full use of the latent heat of vaporization of the exhaust steam of the cond...

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Problems solved by technology

[0005] The extraction condensing or pure condensing steam turbine unit is operated under the condition of high back pressure heating supply after the high back pressure heating supply transformation, and the exhaust steam of the steam turbine is used to heat the high temperature circulating water to realize external heat supply, which is very economical and the thermal efficiency of the unit reaches 94 % or more, even if the efficiency of the high, medium and low pressure cylinders of the unit does not reach the design value, it only reduces the generating power of the unit and the heat-to-electricity ratio of the unit changes, but the thermal efficiency of the unit is still high, and due to the heating circulating water flow and The heating parameters vary greatly, and the first and second types of corrections to the unit test results cannot be carried out. The test results cannot be compared with the design values ​​under the design conditions. Therefore, it is impossible to evaluate the condensing steam turbine according to the usual evaluation method of the performance index of the heating unit. High back pressure retrofitting technology and the performance of the flow-through part after retrofitting

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