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CN-121996871-A - Method for calculating condensate amount of overhead steam pipeline

CN121996871ACN 121996871 ACN121996871 ACN 121996871ACN-121996871-A

Abstract

The invention belongs to the technical field of heat supply engineering, and particularly relates to a method for calculating the condensate quantity of a steam overhead pipeline. The method aims at solving the problem that the flow of condensed hot water in the steam overhead pipeline cannot be accurately detected, and comprises the steps of calculating the theoretical non-condensing section length L 1 of the steam overhead pipeline without considering resistance loss, calculating flow resistance loss according to the value of L 1 , and correcting to obtain the actual non-condensing section pipeline length L 2 . Calculating the condensation section length L 3 of the steam overhead pipeline, calculating the flow resistance loss according to the condensation section length L 3 to obtain the corrected condensation section pipeline length L 4 , calculating the heat dissipation loss phi 1 of the corrected condensation section pipeline in unit length, and calculating the condensation water quantity Q in the actual condensation section pipeline according to the calculation result.

Inventors

  • XIONG JINGRUI
  • YIN WEIGANG
  • CAI WEIBIN

Assignees

  • 丹阳中鑫华海清洁能源有限公司

Dates

Publication Date
20260508
Application Date
20260116

Claims (10)

  1. 1. A method for calculating the condensate level of a steam overhead line, comprising the steps of: calculating the theoretical non-condensing section length L 1 of the steam overhead pipeline without considering resistance loss; Calculating the flow resistance loss according to the theoretical non-condensing section length L 1 , and correcting to obtain the actual non-condensing section pipeline length L 2 ; Calculating the length L 3 of a condensation section of the steam overhead pipeline; Calculating the flow resistance loss according to the length L 3 of the condensation section to obtain the length L 4 of the pipeline of the corrected condensation section; calculating heat dissipation loss phi 1 of the corrected condensation section pipeline in unit length; And calculating the condensation water quantity Q in the pipeline of the actual condensation section according to the calculation result.
  2. 2. A method for calculating the condensate level of a steam overhead line according to claim 1, wherein the calculating is performed without taking into account the loss of drag, the theoretical non-condensing section length L 1 of the steam overhead line is specifically: calculating the total heat transfer resistance R of the steam overhead pipeline; Calculating steam loss heat phi 3 of the steam overhead pipeline in the non-condensing section; According to the total heat transfer resistance R of the steam overhead pipeline, calculating the heat dissipation loss phi 2 of the steam overhead pipeline in a non-condensing section in unit length; The theoretical non-condensing tubing length L 1 =φ 3 /φ 2 is calculated.
  3. 3. A method for calculating the condensation water quantity of a steam overhead pipeline according to claim 2, wherein the calculation of the total heat transfer resistance R of the steam overhead pipeline is specifically: Calculating the forced convection heat transfer thermal resistance Rn of the inner wall of the steam pair pipe; calculating the heat conduction resistance Rg from the inner wall of the pipe to the outer wall of the pipe; calculating heat conduction resistance Rb from the inner surface of the heat preservation layer to the outer surface of the heat preservation layer; Calculating natural convection heat transfer thermal resistance Rw from the outer surface of the heat preservation layer to the atmosphere; the total heat transfer resistance of the steam overhead pipeline is R=Rn+Rg+Rb+Rw.
  4. 4. A method for calculating the condensate level of a steam overhead line according to claim 2, wherein the calculating the steam loss heat phi 3 of the steam overhead line in the non-condensing section is specifically: Determining an initial enthalpy h 1 of steam at the inlet of the pipeline; Determining a theoretical dry saturated steam enthalpy value h2 of the tail end of the non-condensing pipeline without considering resistance loss; determining an initial flow rate Q 1 of the steam at the inlet of the pipeline; And calculating the heat phi 3 =Q 1 （h 1 - h 2 lost by the steam overhead pipeline in the non-condensing section according to the data.
  5. 5. A method for calculating the condensation water quantity of a steam overhead pipeline according to claim 2, wherein the heat dissipation loss quantity phi 2 of the steam overhead pipeline in a non-condensation section per unit length is specifically: Determining the average heat transfer temperature difference delta t 1 of the steam overhead pipeline according to the average temperature of the superheated steam in the pipeline and the ambient temperature; according to the number and the size of the pipeline supporting and hanging frames, determining a heat dissipation loss coefficient beta of the pipeline accessory; the heat dissipation loss of the non-condensing section of the steam overhead pipeline in unit length is phi 2 =Δt 1 (1+beta)/R.
  6. 6. The method for calculating the condensate flow of a steam overhead line according to claim 1, wherein the calculating the flow resistance loss according to the theoretical non-condensing section length L 1 , and the correcting the actual non-condensing section length L 2 is specifically: Calculating the flow resistance loss delta P 1 of the non-condensable pipeline; Determining a pipeline inlet initial steam pressure P 1 ; Calculating the actual pressure P 2 = P 1 -ΔP 1 of the tail end of the non-condensable pipeline; Determining a dry saturated steam enthalpy value h 3 corresponding to the actual pressure P 2 at the tail end of the non-condensing pipeline; Calculating the change quantity delta h 1 =h 2 - h 3 of the enthalpy value of the dry saturated steam corresponding to the pressure of the outlet end of the non-condensing pipeline caused by the flow resistance; Calculating the extension delta L 1 =Δh 1 /φ 2 of the non-condensable pipeline caused by the flow resistance; and calculating the actual length L 2 =L 1 +ΔL 1 of the non-condensing pipeline.
  7. 7. A method for calculating the condensate level of a steam overhead line according to claim 1, wherein the calculating the condensate length L 3 of the steam overhead line is specifically: determining the total length L of the steam overhead pipeline; the condensing section length L 3 =L-L 2 .
  8. 8. The method for calculating the condensate flow of a steam overhead line according to claim 1, wherein the calculating the flow resistance loss according to the condensation segment length L 3 , the obtaining the corrected condensation segment line length L 4 is specifically: Calculating the flow resistance loss delta P 2 in the condensation pipeline length L 3 ; Calculating the actual pressure P 3 = P 2 -ΔP 2 at the end of the condensing pipeline; Determining a dry saturated steam enthalpy value h 4 corresponding to the actual pressure P 3 at the tail end of the condensing pipeline; Calculating the change quantity delta h 2 = h 3 - h 4 of the enthalpy value of the dry saturated steam corresponding to the pressure at the tail end of the condensing pipeline caused by the flow resistance; calculating the extension delta L 2 =Δh 2 /φ 2 of the non-condensable pipeline caused by the flow resistance; And calculating the actual length L 4 =L 3 -ΔL 2 of the corrected condensing pipeline.
  9. 9. The method for calculating the condensate volume of a steam overhead pipeline according to claim 1, wherein the calculating the heat dissipation loss phi 1 of the actual condensation section pipeline in unit length is specifically as follows: Determining an average heat transfer temperature difference delta t 2 of the steam overhead pipeline according to the average temperature of the wet saturated steam in the pipeline and the ambient temperature; and the heat dissipation loss phi 1 =Δt 2 (1+beta)/R of the condensation section of the steam overhead pipeline in unit time and unit length.
  10. 10. A method for calculating the condensate level of a steam overhead line according to claim 1, wherein the calculating the condensate level Q in the actual condensation section line is specifically: Determining the vaporization latent heat q of the steam; The actual condensate flow q=l 4 ×φ 1 /Q of the condensate line is calculated.

Description

Method for calculating condensate amount of overhead steam pipeline Technical Field The invention belongs to the technical field of heat supply engineering, and particularly relates to a method for calculating the condensate quantity of a steam overhead pipeline. Background The heating steam is usually transported over long distances by overhead pipes, some of which are even up to several tens of kilometers. These heating pipes inevitably have heat dissipation losses due to the high temperature of the heating steam. Therefore, when the steam flows in the pipeline, the enthalpy of the steam gradually decreases along with continuous heat dissipation, and when the enthalpy of the steam is lower than the enthalpy of dry saturated steam corresponding to the steam pressure, the steam is condensed, so that the steam enters a wet saturated state from an overheated state, and condensed saturated water is mixed in the steam in the form of tiny liquid drops. The current flow meters installed on the heating pipe network are usually gas flow meters, and once the steam condenses into saturated water, the gas flow meters will not detect, and the liquid flow meters will not detect micro droplets mixed in the steam. Therefore, a problem commonly existing in the heat supply network is that the steam flow input by the heat supply enterprise at the inlet end of the heat supply network is not matched with the steam flow detected by the user at the tail end of the heat supply network (the difference between the steam flow and the steam flow is the condensed hot water flow in the transportation process), so that the heat supply enterprise and the heat users are greatly separated in heat settlement (steam and hot water), and particularly when the number of the terminal heat users is large, the hot water content in the steam used by each heat user is difficult to determine, so that the heat supply enterprise and the heat users can always settle only according to the steam flow, the hot water is equivalent to white loss, and high loss is caused to the heat supply enterprise. Therefore, the method for researching the condensation water quantity of the steam in the overhead pipeline is significant, and a new way is provided for solving the problem that the flow of tiny liquid drops in the steam cannot be detected, so that settlement divergence between a heat supply enterprise and a heat user is solved. Disclosure of Invention Aiming at the problem that the condensed hot water flow rate of the steam overhead pipeline cannot be accurately detected, the invention provides a method for calculating the condensed hot water flow rate of the steam overhead pipeline, which has the advantages of advanced principle and simple calculation, can calculate the condensed hot water flow rate in the pipeline under various conditions of different pipeline lengths, different pipe diameters, different pipeline heat preservation thicknesses, different steam primary parameters and the like, and provides a basis for heat settlement between a heat supply enterprise and a heat user. The invention adopts the following technical scheme to achieve the aim: the invention provides a method for calculating the condensation water quantity of a steam overhead pipeline, which comprises the following steps: calculating the theoretical non-condensing section length L 1 of the steam overhead pipeline without considering resistance loss; Calculating the flow resistance loss according to the theoretical non-condensing section length L 1, and correcting to obtain the actual non-condensing section pipeline length L 2; Calculating the length L 3 of a condensation section of the steam overhead pipeline; Calculating the flow resistance loss according to the length L 3 of the condensation section to obtain the length L 4 of the pipeline of the corrected condensation section; calculating heat dissipation loss phi 1 of the corrected condensation section pipeline in unit length; And calculating the condensation water quantity Q in the pipeline of the actual condensation section according to the calculation result. The principle of the scheme is that if the condensation water quantity in the pipeline is to be calculated, the key is to calculate the length of the condensation section of the pipeline and the heat dissipation quantity per unit length. To achieve this, the heating conduit may be divided generally into two parts, namely a non-condensing section and a condensing section. The total length of the tubing is typically fixed (known), so to calculate the length of the coagulated segment, the length of the uncondensed segment is first calculated. The length of the non-condensing section is mainly determined by the initial enthalpy value of the steam and the heat dissipation rate of the pipeline, and meanwhile, the fact that the flow resistance causes the pressure of the steam to be reduced, so that the enthalpy value of the steam changes and the length of the non-condensing secti