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CN-121854274-B - Heating control method for engine gas conveying pipeline of marine gas generator set

CN121854274BCN 121854274 BCN121854274 BCN 121854274BCN-121854274-B

Abstract

The invention discloses an engine gas conveying pipeline heating control method of a marine gas generator set, which relates to the technical field of marine gas power systems and comprises the steps of collecting multidimensional environmental state information of a gas conveying pipeline in real time, analyzing gas components and pressure fluctuation data, calculating theoretical dew point temperature and potential wax precipitation temperature under real-time pressure by combining a gas physical property database, building a real-time heat exchange model by combining pipeline outer wall temperature gradients and cabin environmental temperature, obtaining theoretical temperature attenuation curves of different positions of gas in the pipeline, comparing the theoretical temperature attenuation curves with predicted condensation and wax precipitation risk positions and degrees, and generating different-section differential electric tracing control strategies of the pipeline by combining cabin relative humidity data. The method can adapt to the real-time physical properties of the fuel gas and the heat exchange state of the pipeline section, and optimize the heating control execution mode of the fuel gas pipeline.

Inventors

  • LI LONGLONG
  • LI SHANSHAN
  • OU XUEQIN
  • CAI LEI
  • GUO YUANLONG

Assignees

  • 潍坊华众动力设备有限公司

Dates

Publication Date
20260505
Application Date
20260317

Claims (10)

  1. 1. The engine gas conveying pipeline heating control method of the marine gas generator set is characterized by comprising the following steps of: Acquiring multidimensional environmental state information of gas components and pressure fluctuation data at an inlet of a gas delivery pipeline of an engine, temperature gradient distribution data of a metal outer wall of the pipeline and environmental temperature and relative humidity change data of a cabin where the pipeline is positioned in real time; Analyzing the gas component and pressure fluctuation data at the inlet of the pipeline, identifying the content of the main component of methane, the proportion of the auxiliary component of high-carbon hydrocarbon and the period and amplitude of pressure pulsation of the current gas, and calculating to obtain the theoretical dew point temperature and the potential wax precipitation temperature of the current gas under the monitored pressure condition by combining a preset gas physical property database; Carrying out fusion analysis on the temperature gradient distribution data of the metal outer wall of the pipeline and the environmental temperature change data of a cabin where the pipeline is positioned, constructing a real-time heat exchange model of the engine gas conveying pipeline, and calculating theoretical temperature attenuation curves of the gas in the pipeline at different positions based on the real-time heat exchange model; Predicting the risk position and the risk degree of condensation or waxing of the gas in the pipeline on a conveying path according to the comparison relation between the theoretical dew point temperature, the potential waxing temperature and the theoretical temperature decay curve; based on the risk position and the risk degree of condensation or waxing, and combining the promotion effect of the relative humidity change data on the condensation of the pipe wall, a differential electric tracing control strategy for different sections of the engine gas conveying pipeline is generated.
  2. 2. The method for controlling heating of an engine gas delivery pipeline of a marine gas generator set according to claim 1, wherein analyzing the gas component and the pressure fluctuation data at the inlet of the pipeline, and identifying the methane main component content, the high-carbon hydrocarbon subcomponent proportion and the cycle and the amplitude of the pressure pulsation of the current gas comprises: performing component separation and quantitative analysis on the gas sample continuously extracted at the inlet of the pipeline by utilizing an online gas chromatography analysis technology to obtain the mole percentage content of methane as the content of the main component of the methane; in the quantitative analysis result, cumulatively calculating the sum of the mole percentage contents of ethane, propane, butane and hydrocarbon with carbon number more than or equal to 5 as the minor component proportion of the high-carbon hydrocarbon; Performing time domain analysis on the pressure fluctuation data, extracting periodic fluctuation components in a pressure signal, and calculating the repetition time interval of the fluctuation components as the period of the pressure pulsation; calculating a difference between a maximum value and a minimum value of the pressure fluctuation data in a period of a single pressure pulsation as an amplitude of the pressure pulsation; and (3) storing the content of the main component of methane, the proportion of the auxiliary component of high-carbon hydrocarbon and the period and the amplitude of the pressure pulsation to the current gas state record after associating the time stamp.
  3. 3. The method for controlling heating of an engine gas delivery pipeline of a marine gas generator set according to claim 2, wherein the calculating the theoretical dew point temperature and the potential wax precipitation temperature of the current gas under the monitored pressure condition by combining a preset gas physical property database comprises: Taking the proportion of the main component content of the methane to the high-carbon hydrocarbon auxiliary component as a query index, and retrieving saturated vapor pressure data and heavy hydrocarbon crystallization characteristic data of corresponding component fuel gas under different pressures from the preset fuel gas physical property database; extracting a real-time average pressure value from the gas pressure fluctuation data at the pipeline inlet; Based on the real-time average pressure value and the retrieved saturated vapor pressure data, determining the temperature corresponding to the saturated state of the vapor in the fuel gas through iterative calculation, and taking the temperature as the theoretical dew point temperature; Determining the temperature at which the high-carbon hydrocarbon component in the fuel gas starts to precipitate solid wax crystals as the potential wax precipitation temperature through a phase balance calculation model based on the real-time average pressure value, the proportion of the high-carbon hydrocarbon auxiliary components and the retrieved heavy hydrocarbon crystallization characteristic data; And correlating the calculated theoretical dew point temperature and potential wax precipitation temperature to the current gas state record.
  4. 4. The method for controlling heating of an engine gas delivery pipeline of a marine gas generator set according to claim 3, wherein constructing a real-time heat exchange model of the engine gas delivery pipeline, calculating theoretical temperature decay curves of gas inside the pipeline at different positions based on the real-time heat exchange model comprises: Converting the temperature gradient distribution data of the metal outer wall of the pipeline into a series of outer wall temperature measuring point temperatures distributed along the axial direction of the pipeline; Converting the environmental temperature change data of the cabin where the pipeline is positioned into an environmental reference temperature corresponding to the series of outer wall temperature measuring points; dividing the engine gas conveying pipeline into a plurality of continuous micro-element pipe sections according to gas flow characteristics and pipeline geometric parameters; for each micro-element pipe section, calculating a theoretical outlet temperature of the fuel gas after flowing through the micro-element pipe section based on an energy conservation equation according to the inlet fuel gas temperature, the temperature of the outer wall temperature measuring point, the environment reference temperature and the heat conduction parameters of the pipeline materials, wherein the theoretical outlet temperature is taken as the inlet fuel gas temperature of the next adjacent micro-element pipe section; Starting from the known actual gas temperature at the inlet of the pipeline, sequentially calculating the gas temperature changes of all the micro-element pipe sections according to the gas flowing direction, and finally obtaining a gas temperature predicted value sequence distributed along the axial direction of the whole pipeline, wherein the gas temperature predicted value sequence forms the theoretical temperature decay curve.
  5. 5. The method for controlling heating of an engine gas delivery line of a marine gas generator set according to claim 4, wherein predicting a risk position and a risk degree of condensation or waxing of the gas in the line on a delivery path according to a comparison relation between the theoretical dew point temperature, the potential waxing temperature and the theoretical temperature decay curve comprises: comparing the theoretical gas temperature value of each position with the theoretical dew point temperature one by one along the theoretical temperature decay curve; Marking a position of which the theoretical gas temperature value is lower than the theoretical dew point temperature as a condensation risk point, and calculating a difference value between the theoretical dew point temperature and the theoretical gas temperature value to serve as a theoretical condensation risk degree of the condensation risk point; Comparing the theoretical gas temperature value of each position with the potential wax precipitation temperature one by one along the theoretical temperature decay curve; marking a position of which the theoretical gas temperature value is lower than the potential paraffin deposition temperature as a paraffin deposition risk point, and calculating a difference value between the potential paraffin deposition temperature and the theoretical gas temperature value to serve as a theoretical paraffin deposition risk degree of the paraffin deposition risk point; And summarizing the position coordinates, risk types and theoretical risk degrees of the condensation risk points and the wax precipitation risk points, and generating a pipeline risk prediction map.
  6. 6. The method for heating control of an engine gas delivery line of a marine gas generator set of claim 5, wherein generating differential electrical tracing control strategies for different sections of the engine gas delivery line in combination with the promotion of tube wall condensation by the relative humidity change data comprises: the differential electric tracing control strategy comprises a heating power set value, a heating rate and a heating start time for a specified pipeline section; Calculating the absolute humidity of cabin air according to the relative humidity change data of a cabin where the pipeline is located, and estimating the critical condition of surface condensation on the outer wall of the pipeline by combining the environmental temperature change data; Superposing the estimated critical condition of the surface condensation on the outer wall of the pipeline with the pipeline risk prediction map, and if the external environment of the pipe section with theoretical condensation risk or wax precipitation risk meets or approaches the critical condition of the surface condensation at the same time, improving the risk level of the pipe section; Taking the risk points and the risk grades marked in the pipeline risk prediction map as core basis, and combining with the electric tracing partition design of the gas conveying pipeline, setting control parameters for each electric tracing partition; For a pipeline section with high risk level, setting a heating power set value determined based on a first preset power mapping table and a heating rate determined based on a first preset rate mapping table, and setting to immediately start heating or starting heating based on a first time threshold preset in advance of the risk level; for the pipeline section with low risk level, setting a heating power set value determined based on a second preset power mapping table and a heating rate determined based on a second preset rate mapping table, and setting to delay a preset second time threshold to start heating or intermittently heating according to a preset duty ratio; The reference power value corresponding to the first preset power mapping table is higher than the second preset power mapping table, and the reference heating rate corresponding to the first preset rate mapping table is higher than the second preset rate mapping table; And integrating the heating power set values, the heating rate and the heating start time of all electric tracing partitions to form a global differential electric tracing control strategy.
  7. 7. The method according to claim 6, wherein the determining, based on the real-time average pressure value, the higher hydrocarbon subcomponent ratio and the retrieved heavy hydrocarbon crystallization characteristic data, the temperature at which the higher hydrocarbon component in the gas starts to precipitate solid wax crystals as the potential wax precipitation temperature by a phase balance calculation model comprises: Extracting solid-liquid phase equilibrium constants of all heavy hydrocarbon components contained in the current gas high-carbon hydrocarbon components at different temperatures from the heavy hydrocarbon crystallization characteristic data; Inputting the real-time average pressure value, the higher hydrocarbon subcomponent proportion and the initial mole fraction of each heavy hydrocarbon component into a phase balance calculation model based on a state equation, wherein the phase balance calculation model adopts a PR equation or an SRK equation applicable to hydrocarbon mixtures; Setting an initial temperature value, and calculating distribution coefficients of various heavy hydrocarbon components in a gas phase and a virtual solid phase by using the phase balance calculation model under the initial temperature value and the real-time average pressure value; Calculating the sum of mole fractions of all high-carbon hydrocarbon components in the fuel gas in the imaginary solid phase, and judging whether the sum is larger than a preset crystallization threshold value or not; if the mole fraction sum is smaller than or equal to the crystallization threshold, gradually reducing the initial temperature value, and recalling the phase balance calculation model to calculate and judge; when the mole fraction sum is larger than the crystallization threshold value for the first time, determining the system temperature value at the moment as the critical temperature at which the high-carbon hydrocarbon component starts to precipitate solid wax crystals, and taking the critical temperature as the potential wax precipitation temperature.
  8. 8. The method for controlling heating of an engine gas delivery line of a marine gas generator set according to claim 7, further comprising a dynamic correction step of performing feedback based on a strategy: after the differential electric tracing control strategy is executed, the temperature gradient distribution data of the metal outer wall of the pipeline is collected again and updated; The updated temperature gradient distribution data of the metal outer wall of the pipeline is input into the real-time heat exchange model, and an updated theoretical temperature decay curve of the fuel gas is obtained through calculation; Comparing the updated theoretical temperature decay curve of the fuel gas with the theoretical dew point temperature and the potential wax precipitation temperature again, and evaluating the actual elimination condition of condensation and wax precipitation risks; if the risk is not completely eliminated, proportionally increasing the heating power setting of the corresponding pipe section; if risk has been eliminated and the pipeline metal outer wall temperature exceeds a safety margin threshold, proportionally reducing the heating power setting for the corresponding pipeline section; And generating an electric tracing control strategy correction instruction of the next control period according to the evaluation result and the adjusted heating power set value.
  9. 9. The method for controlling heating of engine gas delivery pipeline of marine gas generator set according to claim 8, wherein the step of inputting updated temperature gradient distribution data of the metal outer wall of the pipeline into the real-time heat exchange model to calculate an updated theoretical temperature decay curve of the gas comprises the steps of: Taking the updated temperature gradient distribution data of the metal outer wall of the pipeline as a new boundary condition to replace an original boundary condition used in constructing the real-time heat exchange model; keeping other parameters except boundary conditions in the real-time heat exchange model unchanged, wherein the parameters comprise pipeline geometric parameters, material heat conduction parameters and fuel gas flow characteristic parameters; re-operating the real-time heat exchange model by using new boundary conditions, and re-calculating the theoretical outlet temperature of the fuel gas after flowing through each micro-element pipe section; And (3) calculating the gas temperature changes of all the micro-element pipe sections in sequence from the actual gas temperature at the inlet of the pipeline to obtain an updated gas temperature predicted value sequence, namely the updated gas theoretical temperature decay curve.
  10. 10. The method for controlling heating of an engine gas delivery line of a marine gas generator set according to claim 9, further comprising a heating strategy feedforward compensation step under variable load operation of the engine: Monitoring an engine real-time power output signal of the marine gas generator set; predicting the expected change of the gas flow according to the change trend of the real-time power output signal of the engine; Predicting the expected change of the overall heat loss of the engine gas conveying pipeline through a pre-calibrated gas flow-heat loss rate relation model based on the expected change of the gas flow; according to the expected change direction and amplitude of the overall heat loss, carrying out synchronous feedforward adjustment on a heating power set value in the currently executed differential electric tracing control strategy; before the engine power rises to cause the expected increase of the gas flow, the heating power set value is increased in advance according to the predicted proportion; the heating power setting is reduced in advance by a predicted ratio when the engine power decreases resulting in an expected decrease in gas flow.

Description

Heating control method for engine gas conveying pipeline of marine gas generator set Technical Field The invention belongs to the technical field of ship gas power systems, and particularly relates to a heating control method for an engine gas conveying pipeline of a ship gas generator set. Background The heating control of the engine gas conveying pipeline of the conventional marine gas generator set mainly adopts a fixed threshold regulation and control mode, the unified heating parameters are set only by means of pipeline single-point temperature or cabin environment temperature, the gas dew point temperature and the wax precipitation temperature are both fixed empirical values, dynamic calculation is carried out without combining real-time gas components and pressure fluctuation data, the pipeline heating execution whole course adopts an integral unified regulation and control mode, differential regulation and control are not carried out on heat exchange states of different sections of the pipeline, and the influence of cabin relative humidity on pipe wall condensation is not included in heating control logic. The fixed dew point temperature and wax precipitation temperature values cannot be adapted to the conveying working conditions of the gas components and the real-time change of pressure, the conditions that the deviation between the pre-judging standard of condensation and wax precipitation risks and the physical properties of actual gas is large easily occur, the uniform heating control mode cannot be matched with the temperature attenuation differences of different positions of a pipeline, the problem that the heating parameters are not adapted to the actual heat exchange state exists in part of pipeline sections, the pipe wall condensation risk caused by the relative humidity of a cabin is not included in the regulation and control basis, and the pipeline heating control cannot be attached to the actual risk states of different sections. The theoretical dew point temperature and the potential paraffin precipitation temperature under the corresponding monitoring pressure are calculated dynamically by combining the real-time gas components and the pressure fluctuation data, a pipeline real-time heat exchange model is required to be constructed to obtain theoretical temperature attenuation curves of the gas at different positions of the pipeline, and the differential electric tracing control mode of different sections of the gas conveying pipeline is formed according to the condensation and paraffin precipitation risk positions and degrees and the relative humidity data. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art; therefore, the invention provides an engine gas conveying pipeline heating control method of a marine gas generator set, which comprises the following steps: Acquiring multidimensional environmental state information of gas components and pressure fluctuation data at an inlet of a gas delivery pipeline of an engine, temperature gradient distribution data of a metal outer wall of the pipeline and environmental temperature and relative humidity change data of a cabin where the pipeline is positioned in real time; Analyzing the gas component and pressure fluctuation data at the inlet of the pipeline, identifying the content of the main component of methane, the proportion of the auxiliary component of high-carbon hydrocarbon and the period and amplitude of pressure pulsation of the current gas, and calculating to obtain the theoretical dew point temperature and the potential wax precipitation temperature of the current gas under the monitored pressure condition by combining a preset gas physical property database; Carrying out fusion analysis on the temperature gradient distribution data of the metal outer wall of the pipeline and the environmental temperature change data of a cabin where the pipeline is positioned, constructing a real-time heat exchange model of the engine gas conveying pipeline, and calculating theoretical temperature attenuation curves of the gas in the pipeline at different positions based on the real-time heat exchange model; Predicting the risk position and the risk degree of condensation or waxing of the gas in the pipeline on a conveying path according to the comparison relation between the theoretical dew point temperature, the potential waxing temperature and the theoretical temperature decay curve; based on the risk position and the risk degree of condensation or waxing, and combining the promotion effect of the relative humidity change data on the condensation of the pipe wall, a differential electric tracing control strategy for different sections of the engine gas conveying pipeline is generated. Further, analyzing the gas component and the pressure fluctuation data at the inlet of the pipeline, and identifying the content of the main component of methane, the proportion of the a