Calculation method of inlet steam enthalpy of air-cooled condenser of direct air-cooled unit

Abstract

The invention discloses a method for calculating the inlet steam enthalpy of the air-cooled condenser of a direct air-cooling unit. The specific steps are: 1. Measure the condensed water flow rate entering the deaerator, the leakage steam flow rate of the front and rear shaft seals of the high and medium pressure cylinders, and the shaft seal flow rate of the low pressure cylinder. Steam flow, high and medium pressure cylinder inlet valve stem leakage flow, and sealing water flow into the feed pump; 2: According to the energy balance and mass balance of the high pressure heater and deaerator, calculate the steam extraction flow in the first to fourth stages , feed water flow, main steam flow, high-pressure cylinder exhaust steam flow and reheat steam flow; 3: According to the heat balance and mass balance of the low-pressure heater, calculate the extraction steam flow in the fifth to seventh stages, and calculate according to the energy balance and mass balance of the steam turbine Exhaust energy and exhaust flow of low-pressure cylinder of steam turbine. Four: Calculate the exhaust steam enthalpy of the low-pressure cylinder, that is, the steam inlet enthalpy of the air-cooled condenser, as the benchmark for calculating the heat load of the air-cooled condenser. The measurement results are more accurate.

Description

technical field [0001] The invention relates to a method for calculating the inlet steam enthalpy of an air-cooled condenser of a direct air-cooling unit. Background technique [0002] At present, in my country's "Three North" regions, air-cooled units are developing rapidly. Since the air-cooled condensers of the air-cooled units put into production in the early stage mostly adopt foreign technology and products, the acceptance test of domestic air-cooled condensers is basically in accordance with foreign VGB-R131Me The guideline proceeds. The domestic test standards and specifications for air-cooled condensers are mainly the industry standard DL / T552-1995 "Test methods for air-cooled towers and air-cooled condensers in thermal power plants", which includes specific requirements for tests on air-cooled towers and air-cooled condensers . [0003] Both of the above two test standards use the state point of the low-pressure cylinder to reheat and extract steam to draw the exp...

AI Technical Summary

Problems solved by technology

The above two factors will lead to the difference between the actual steam expansion process and the design expansion process, which will cause the steam expansion process line in the low-pressure cylinder to present a nonlinear relationship, resulting in the determined low-pressure cylinder exhaust steam enthalpy, that is, the condenser inlet steam enthalpy. Large deviations will eventually affect the accuracy of the performance calculation results of the condenser

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