Correction method for multi-point measurement of steam drum liquid level of high pressure boiler

Abstract

The invention discloses a correction method for multi-point measurement of a steam drum liquid level of a high pressure boiler. The method comprises the following steps of: calculating a range and migration of a differential pressure transmitter according to height between a liquid level measurement device and two connecting ports of a steam drum, height from the liquid level measurement device and the lower connecting port of the steam drum to the differential pressure transmitter, saturated water density and saturated steam density in the steam drum and condensate density in the liquid level measurement device; inputting the range and the migration to the differential pressure transmitter to serve as an original zero point and an original range; actually measuring a thermal-state zero value PA and a thermal-state range value PR of the differential pressure transmitter; calculating effective measuring ranges in PA and PR; establishing polygonal function relation; corresponding an effective thermal-state zero value Pr and an effective thermal-state range value Pr to a zero value La and a range value Lr of liquid level indication respectively; displaying according to linear relation; and performing temperature and pressure compensation calculation on La, Lr, steam drum temperature Tsteam and steam drum pressure Psteam to acquire a corrected value of the steam drum liquid level Ldelta so as to play a role in three-impulse adjustment and interlocking control of the steam drum liquid level.

Description

technical field [0001] The invention belongs to the technical field of liquid level measurement, and relates to a liquid level measurement correction method, in particular to a high pressure boiler steam drum liquid level multi-point correction method. Background technique [0002] Coal chemical production is inseparable from high-temperature and high-pressure boilers. Due to the complexity of the coal chemical process, the steam load demand for high-temperature and high-pressure boilers changes frequently, resulting in the phenomenon of "false liquid level" in high-temperature and high-pressure boilers from time to time. [0003] In order to ensure the safe operation of the boiler and steam drum, in the steam drum liquid level control scheme, more than three steam drum liquid level detection points are usually set up to meet the requirements of three-impulse liquid level adjustment and three-take-two liquid level interlock protection . [0004] When using multi-point monit...

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Problems solved by technology

[0004] When using multi-point monitoring of the liquid level on the steam drum, due to the different structure and installation position of the measuring device, and the measurement medium water and steam are in a state of high temperature and high pressure, they are greatly affected by temperature and pressure, resulting in relatively large deviations in liquid level measurement. Large, can not guarantee the accuracy and consistency of multi-point liquid level measurement, which seriously affects the control of the drum liquid level

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