CN-121993780-A - Steam drum water level control system of single-chamber balance container of boiler

CN121993780ACN 121993780 ACN121993780 ACN 121993780ACN-121993780-A

Abstract

The invention relates to the technical field of boiler drum water level measurement, in particular to a drum water level control system of a boiler single-chamber balance container, which comprises a drum and a water level measurement mechanism, wherein a steam side sampling tube and a water side sampling tube are respectively fixed on the drum, the water level measurement mechanism comprises a single-chamber balance container and a differential pressure transmitter, the drum water level measurement process comprises the following steps of firstly respectively obtaining pressure P in the drum, temperature T1 of a reference water column in a positive pressure communicating pipe and temperature T2 in the drum, secondly obtaining density rho 1 of the reference water column in the positive pressure communicating pipe, density rho 2 of saturated water in the drum and density rho 3 of saturated steam in the drum, thirdly, judging whether the temperature T2 in the drum is higher than 80 ℃, if yes, executing step IV, executing thermal compensation calculation, and thirdly, executing cold state calculation. The invention can accurately measure the drum water level and ensure the running stability of the boiler.

Inventors

LIU YU

Assignees

中国石油化工股份有限公司
中国石化集团重庆川维化工有限公司

Dates

Publication Date: 20260508
Application Date: 20241108

Claims (8)

1. The steam drum water level control system of the single-chamber balance container of the boiler comprises a steam drum and a water level measuring mechanism, wherein a steam side sampling pipe and a water side sampling pipe are respectively fixed on the steam drum, the water level measuring mechanism comprises the single-chamber balance container and a differential pressure transmitter which are communicated between the steam side sampling pipe and the water side sampling pipe, and is characterized in that: The one end that the steam pocket was kept away from to the single-chamber balancing container is connected with the positive pressure end of differential pressure transmitter through the positive pressure communicating pipe, the water side sampling tube is connected with the negative pressure end of differential pressure transmitter through the negative pressure communicating pipe, still install temperature transmitter on the positive pressure communicating pipe, install pressure transmitter on the negative pressure communicating pipe.
2. The drum water level control system of a single-chamber balance vessel of a boiler of claim 1, wherein the drum water level control process comprises the steps of: step one, respectively acquiring the pressure P in a steam drum, the temperature T1 of a reference water column in a positive pressure communicating pipe and the temperature T2 in the steam drum; Step two, according to the data obtained in the step I, obtaining the density rho 1 (Kg/m 3) of a reference water column in the positive pressure communicating pipe, the density rho 2 (Kg/m 3) of saturated water in the steam drum, and the density rho 3 (Kg/m 3) of saturated steam in the steam drum; Judging whether the temperature T2 in the steam drum is higher than 80 ℃, if so, executing the fourth step, and if not, executing the fifth step; step four, performing thermal compensation calculation and outputting a calculation result; And fifthly, performing cold state calculation and outputting a calculation result.
3. The boiler single-chamber balance tank drum water level control system according to claim 2, wherein in the drum water level control process, the thermal compensation calculation formula is as follows: Δh＝-1/4*(-4ρ 1 L+ρ 1 m-ρ 2 m+4H 0 ρ 2 +4ρ 3 L-4H 0 ρ 3 +4*D*ΔP)/(ρ 2 -ρ 3 ); h=Δh+H 0 ; Wherein m is the distance between the reference liquid level in the single-chamber balance container and the lower surface of the horizontal section of the positive pressure communicating pipe, Δh is the difference value (mm) between the actual water level of the steam drum and the normal running water level of the steam drum, H 0 is the distance (mm) between the normal running water level of the steam drum and the center of the water side sampling tube, L is the distance (mm) between the reference liquid level in the single-chamber balance container and the center of the water side sampling tube, D is a unit conversion coefficient, ΔP is the differential pressure value (Pa) corresponding to the water level of the steam drum, and H is the distance (mm) between the actual water level of the steam drum and the center of the water side sampling tube.
4. The boiler single-chamber balance tank drum water level control system of claim 3, wherein in step five of said drum water level control process, the cold state calculation formula is as follows: Δh=-(-Lρ 1 +H 0 ρ 1 +DΔP)/ρ 1 ; h=Δh+H 0 。
5. The boiler single-chamber balance tank drum water level control system of claim 1-4 wherein said temperature transmitter, pressure transmitter and differential pressure transmitter are all electrically connected to a drum water level gauge DCS system.
6. The boiler single-chamber balance tank drum level control system of claim 5, wherein: a temperature sensor is also arranged in the steam drum.
7. The steam drum water level control system of a single-chamber balance container of a boiler according to claim 6, wherein the distance m between the reference liquid level of the single-chamber balance container and the lower surface of the horizontal section of the positive pressure communicating pipe is equal to twice the pipe diameter of the horizontal section of the positive pressure communicating pipe.
8. The system of claim 7, wherein in the fifth step of the drum water level measuring process, h is calculated in a cold state as a water level when the boiler equipment is not operated or when water in the drum is not saturated.

Description

Steam drum water level control system of single-chamber balance container of boiler Technical Field The invention relates to the technical field of boiler drum water level measurement, in particular to a drum water level control system of a single-chamber balance container of a boiler. Background A boiler is an energy conversion device that can convert chemical energy or electric energy in fuel into heat energy and output steam, high temperature water or an organic heat carrier having a certain heat energy. The boiler consists of two parts, namely a boiler and a furnace, wherein the boiler refers to a steam-water flow system which comprises a boiler barrel, a header, a water-cooled wall, a convection heating surface and the like and is a heat absorption part of heat exchange equipment, and the furnace refers to a fuel combustion space and a flue-air flow system which comprises a hearth, a convection flue, a chimney and the like and is a heat release part of the heat exchange equipment. The drum in a boiler, also called drum, is a cylindrical pressure vessel in a water tube boiler for steam-water separation, steam purification, forming a water circulation loop and storing boiler water. Maintaining the water level of the drum within a certain range is a necessary condition for ensuring safe operation of the boiler. If the water level of the steam drum is too low, natural circulation of steam and water of the boiler is destroyed, so that a water wall pipe of the boiler is burnt out, and accidents such as pipe explosion and the like can also occur when water is seriously lacked. Therefore, the measurement and regulation of the drum water level are important links for ensuring the stable and safe operation of the boiler, and safety accidents caused by abnormal water level can be avoided. As shown in fig. 1, the conventional drum water level measuring apparatus mostly adopts an external balance container (such as a single-chamber balance container 3), one end of the single-chamber balance container 3 is communicated with a steam side sampling tube 2 of a boiler, the other end of the single-chamber balance container 3 is connected to a positive pressure end 5 of a differential pressure transmitter through a positive pressure communicating tube 4, a negative pressure end 6 of the differential pressure transmitter is connected with a water side sampling tube 8 of the drum through a negative pressure communicating tube 7, so that the differential pressure transmitter can measure the pressure difference between the water side and the steam side of the drum, and the difference is transmitted to a DCS system, and the liquid level in the drum can be obtained through system conversion. However, heat exchange exists between the single-chamber balance container and the outside, when saturated steam 101 in the steam drum 1 enters the single-chamber balance container 3 from the steam side sampling tube 2, the saturated water is condensed, the surface water temperature of a reference liquid level 301 in the single-chamber balance container 3 approaches to the saturated temperature, the positive pressure communicating tube 4 has a certain height, the water temperatures in the reference liquid level 301 and the positive pressure communicating tube 4 are gradually reduced along with the reduction of the height, so that the reference liquid level 301 and the reference water column in the positive pressure communicating tube 4 are actually unsaturated water, the density of the unsaturated water is different from that of the saturated water, but the balance container usually regards the water in the reference water column as saturated water when calculating the actual water level of the steam drum, thus the calculated liquid column pressure of the reference water column is inaccurate, the steam drum water level converted by the system is inconsistent with the actual water, the interlocking protection rejection or malfunction of a boiler is easily caused, the stable operation of the boiler is influenced, and serious economic loss and safety accidents are caused. Disclosure of Invention The invention provides a drum water level control system of a single-chamber balance container of a boiler, which can solve the problems that the drum water level detection value and the actual value in the prior art are not consistent, so that the stable operation of the boiler is influenced, and safety accidents are easy to cause. The application provides a technical scheme that a steam drum water level control system of a single-chamber balance container of a boiler comprises a steam drum and a water level measuring mechanism, wherein a steam side sampling pipe and a water side sampling pipe are respectively fixed on the steam drum, and the water level measuring mechanism comprises the single-chamber balance container and a differential pressure transmitter which are communicated between the steam side sampling pipe and the water side sampling pipe;