LeadingScholarForumResearchonAccidentConditionsandFailureEvaluationofCityGasPipelineNetwork

JIAO Wenling, REN Lemei, TANG Shengnan, JIANG Saisai

Abstract： In order to grasp the hydraulic conditions of the high and medium pressure pipeline network after accidents, and lay a foundation for the pipeline network accident assessment and pipeline network dispatching, a hydraulic calculation model using genetic algorithm to solve the accident conditions of pipeline network is proposed to obtain the actual flow of each node and the pressure distribution of the pipeline network after accidents, which is used to analyze the influence extent and degree of the pipeline network accidents. The expression of the node flow guarantee rate is proposed to analyze the influence degree of accidents and guide the scheduling decision of the pipeline network. In order to better evaluate the accident pipeline network, the comprehensive evaluation method is used to establish the failure degree evaluation model of the pipeline network under a gas source accident, and a corresponding performance index table is made according to the failure degree, and the influence of the pipeline network accident is more intuitively evaluated. Through the analysis of the example, the correctness of the hydraulic model and the comprehensive evaluation model of the pipeline network is verified, which provides a theoretical basis for the scheduling decision of the pipeline network accident conditions.

Keywords: gas pipeline network accident condition; genetic algorithm; node flow guarantee rate; failure evaluation; performance index

HeatSourceandColdSourceWorkingFluidSelectionandThermodynamicPerformanceofHeatPump-typeFlueGasEliminationSystem

ZHAO Maozhong, YU Jiatong

Abstract： In order to eliminate white flue gas, and avoid the problem of acid dew point corrosion caused by the heat of flue gas before desulfurization at the same time, the concept of Organic Gas Thermodynamic System (OGTS) is proposed. The vapor compression type heat pump circulation system is used to extract the latent heat of water vapor in flue gas after desulfurization, recover the condensed water and reheat the discharged flue gas. Flow simulation experiments were carried out on the systems using four organic working fluids of R123, R245fa, R134a and BY-pro by Aspen-Plus software. The results show that the system using BY-pro is at an optimal level in terms of coefficient of performance, exergy efficiency and pressure requirements of major equipment.

Keywords: elimination of white flue gas; heat pump-type flue gas elimination system; organic working fluid

PerformanceandApplicationofCirculatingFluidizedBedBoilersandReciprocatingGrateBoilers

DING Liqun, WANG Wei

Abstract： The performance and economy of circulating fluidized bed boilers and reciprocating grate boilers are compared and analyzed, and three boiler application cases are given. It is indicated that when selecting a boiler with low calorific value coal, the large reciprocating grate boiler should be given priority when the single unit evaporation is less than 300 t/h (heat capacity is less than 210 MW). If the low calorific value of the fuel is lower than 12 560.4 kJ /kg, the circulating fluidized bed boiler should be selected.

Keywords: circulating fluidized bed boiler; reciprocating grate boiler; blower; self-consumption electric power; single unit evaporation

ComparisonandSelectionofGas-firedBoilerFlueGasWasteHeatRecoverySchemes

LI Qing, ZHAO Yaozong, GAO Jun, WANG Xun

Abstract： Taking the gas-fired boiler with a thermal power of 5.6 MW as the research object, the Aspen Plus process simulation software is used to establish the simulation processes of conventional flue gas waste heat recovery scheme (Scheme 1), direct contact waste heat recovery scheme (Scheme 2) and direct-fired lithium bromide absorption heat pump unit waste heat recovery plan (Scheme 3). Taking Scheme 1 as a benchmark scheme, the system heating efficiency of the three schemes and the incremental investment recovery period of Schemes 2 and 3 are analyzed and calculated under the premise of 5 494 kW of heat supply. The system heating efficiencies of the three schemes are 94.1%, 99.3%, and 100.7%, respectively. The investment increments of Schemes 2 and 3 are 136×104and 265×104yuan, respectively. The annual operating costs saved by Schemes 2 and 3 are close, but the incremental investment recovery period of Scheme 2 is smaller, and Scheme 2 is more economical.

Keywords: flue gas waste heat recovery; direct contact heat transfer; absorption heat pump; heating efficiency; incremental investment recovery period

SimulationStudyonOptimalDrillingSpacingofMediumandDeepBuriedTubeHeatExchanger

DU Tiantian, MAN Yi, JIANG Guoxin, LI Shuo, ZHANG Xinyu

Abstract： The optimal drilling spacing of the medium and deep casing-type buried tube heat exchanger was simulated by geothermal Star II commercial software. The drilling depth is 2 000 m, the diameter is 446.7 mm, the height of the buried tube is the same as the drilling depth, the circulating water flow mode is outside into and inside out. The heat-taking time is the heating period, and the other time is the soil temperature recovery time. Under the condition that the buried tube takes a certain heat load, the thermal influence radius of the borehole increases with the extension of the operation time. With the extension of the operation time, the heat-taking quantity during the heating period exceeds the natural recovery capacity of the soil, which is not conducive to long-term operation, and should be considered to replenish the heat to the soil. When the buried tube heat exchanger takes heat load of 200 kW, the recommended value of the optimal drilling spacing (the corresponding operation time of 20 years) is 133 m. When the operation time is constant, the thermal influence radius of borehole increases with the increase of heat-taking load. In the actual project, the determination of the optimal drilling spacing of the medium and deep casing-type buried tube heat exchanger should take into account the heat load and the operation time at the same time.

Keywords: medium and deep buried tube heat exchanger; optimal drilling spacing; operation time; heat-taking load

Heat-supplyNetwork,Cooling-supplyNetworkandSubstationStudyonIncreaseofSpacingofSegmentedValvesforHeatingLong-distanceMain

YAN Yongpeng, ZHANG Yuchen, HE Fan, ZHANG Rong, WANG Huai

Abstract： The influences of spacing increase of segmented valves for long-distance main on heating reliability, fault repair time, long-distance main cost and fault repair cost are analyzed. The results show that after increasing the spacing of segmented valves for long-distance main, the total failure rate of the long-distance main decreases, and the heating reliability is improved. The fault repair time will increase, which has no effect on fault detection and location time and net repair time, but will increase the discharge time and the replenishment time of water. In order to reduce or eliminate the influence of spacing increase of segmented valves for long-distance main on the fault repair time, the diameter of water discharge pipe for the long-distance main should be appropriately increased, and the water replenishment capacity of the long-distance main should be increased. Although the water replenishment cost increases during the fault repair, the added water replenishment cost is small and can be ignored compared with the saved cost. Therefore, the spacing of segmented valves for long-distance main can be increased from 2 to 3 km to 4 to 6 km.

Keywords: long-distance main; spacing of segmented valves; heating reliability; fault repair; hot water pipeline

TypeSelectionofHeat-insulatedSlidingBracketsforHotWaterPipelineinUrbanUtilityTunnel

HE Fan, ZHANG Rong, YU Yaze

Abstract： Through the analysis of the heat loss of the traditional sliding bracket, combined with the structural parameters of the hot-water pipeline, the selection principle in design of the heat-insulated sliding bracket in the utility tunnel is summarized. For hot-water pipeline of DN 600 mm and below, pipe clamp type heat-insulated sliding bracket can be selected. For the hot-water pipeline of DN 700 to 900 mm, because the minimum width of the pipe clamp exceeds 0.512 m, in order to reduce the width of the single pipe clamp, double-pipe clamp type heat-insulated sliding bracket can be selected. For the hot-water pipeline of DN 1 000 mm and above, because it is difficult to install the pipe clamp type heat-insulated sliding bracket, in order to reduce the difficulty of on-site construction, prefabricated heat-insulated sliding bracket can be selected.

Keywords: urban utility tunnel; sliding bracket; pipe clamp type; heat insulation; heat loss; polyurethane compression strength

InsulationTechnologyforOverheadHotWaterHeatingPipelineofLong-distanceHeat-supplyNetwork

SHI Guanghui

Abstract： Combined with a project of long-distance heating network, the insulation technology of the overhead hot water heating pipeline is discussed. The insulation pipe is prefabricated insulation pipe with galvanized steel for external protection, which was prepared by the spiral seam process. The sliding bracket is partition type insulation bracket, the main device is embedded part, box-type tube holder and sliding plate with PTFE plate. The fixed bracket is integral insulation. By actual measurement, the surface temperature of sliding bracket and valve is relatively high, and the insulation effect still has room for improvement.

Keywords: insulation structure; overhead hot water heating pipeline; prefabricated insulation pipe; sliding bracket; fixed bracket

GasCombustion,GasAppliancesandGasConsumptionEquipmentInfluenceofPolyurethaneBarrieronMethaneAirPremixedFlamePropagation

ZHANG Chenghu, FAN Lijia, YANG Yujie, WEI Jihong, TAN Yufei

Abstract： Aiming at the propagation characteristics of methane air premixed flame in polyurethane barriers, the numerical simulation method is used to carry out research，the characteristics of deflagration overpressure, flame front position and flame temperature of methane air premixed gas in the case of non-reticulated polyurethane material, 10ppi reticulated polyurethane material and 20ppi reticulated polyurethane material. The results show that the smaller the porosity of the reticulated polyurethane, the stronger the inhibition of the deflagration overpressure. When the flame front reaches the inner surface of the reticulated polyurethane barrier, the backtracking phenomenon will occur. When the porosity is large, the flame front will propagate forward again after the backtracking. When the porosity is small, the flame will be extinguished. Due to the destruction of the flame free radicals and the absorption of heat by the reticulated polyurethane material, the deflagration flame temperature of the premixed gas is significantly reduced as the pore size of the reticulated polyurethane barrier is reduced.

Keywords: reticulated polyurethane; deflagration overpressure; flame temperature; flame front; flame propagation

GasTransmission,Distribution,StorageandTransportationApplicationResearchofCalorimeterinNaturalGasEnergyMetering

LI Chijia, WANG Xinwei, CHEN Min, XIAO Yong, ZHANG Yanping, WANG Xun

Abstract： The working principle, performance and installation requirements of a calorimeter are introduced. An experimental system for calorific value measurement is set up, and compared with on-line chromatograph, the calorific value of conventional pipeline natural gas and synthetic natural gas from coal are measured respectively. For the conventional pipeline natural gas, the average relative error with on-line chromatographic measurement is 0.136% after being corrected by the correction coefficient. For the synthetic natural gas from coal, the calorific value calculation method of calorimeter does not consider hydrogen components, and the calorific value correlation model and parameters should consider the influence of hydrogen components.

Keywords: calorimeter; on-line chromatograph; energy metering; calorific value measurement

SummaryofResearchonSafetyofGasCompartmentinDomesticUtilityTunnel

ZHANG Shuhao，PENG Shini， DU Jianmei，ZHAO Wei

Abstract： The research results of safety of gas compartment in utility tunnel are reviewed from the aspects of leakage and diffusion, fire and fire protection, explosion, monitoring, alarming and ventilation. According to the research on leakage and diffusion in the compartment, it is pointed out that the leakage of natural gas pipelines in gas compartment should not only consider the direction and size of leakage holes of pipeline, the operation pressure, the alarming time of flammable gas detector, but also the ventilation changes and pressure changes of pipelines under accident conditions. In the case of a large number of leakage, ventilation alone cannot completely ensure the safety of the compartment, so it is necessary to combine truncation and release measures. According to the current research results of gas explosion in confined space, it is pointed out that the influence of obstacles and the characteristics of long and narrow structure of the compartment should be considered in the simulation study of gas compartment explosion accidents. Otherwise, there is a large deviation in the simulation results; if the intensity of the explosion shock wave is high, measures must be taken to prevent or suppress the explosion. It is recommended to appropriately increase the methane volume fraction setting value in the corresponding compartment when the pipeline is cut off. The pipeline can continue to transmit gas when the gas leaks a little but there is no risk of explosion.

Keywords: utility tunnel; safety; gas compartment; leakage; fire; explosion

ApplicationofNetworkVideoSurveillanceSysteminUrbanUtilityTunnel

WANG Liang

Abstract： The components and technical advantages of the network video surveillance system are summarized. In view of the network video surveillance system of urban utility tunnel, three application schemes of simple, centralized and distributed type are given. The on-site configuration, network architecture and characteristics of each scheme are introduced.

Keywords: urban utility tunnel; network video surveillance system; network architecture

StudyonChangeofGasConsumptionofNaturalGasHeatinginResidentialBuildingsinWuhanCity

LI Yixin, LIN Yana, YANG Fei, DONG Jiankai

Abstract： DeST modeling is used to simulate the heating energy consumption of a residential building in Wuhan City. By setting the parameters of building internal disturbance and enclosure structure, combined with the meteorological parameters of Wuhan City that come with DeST software, the heat supply of the residential building under three intermittent operation modes of heating system are simulated. According to the natural gas parameters of Wuhan City, the gas consumption corresponding to the heating of the building is calculated, and the result can be used as the basic data for natural gas load forecasting. The study results show that among the three intermittent operation modes, mode II is the smallest in the annual cumulative heating unit area index, mode III is the largest, and mode I is centered. Taking the intermittent operation mode I as the analysis object, the relationship between the daily heat supply and daily average outdoor temperature in January, the hourly heat supply of the largest daily heat supply in January, the daily average heat supply for the calendar month and the annual heat supply are simulated. In intermittent operation mode I, the daily heat supply of the residential building reached its maximum value of 1 198 kW on January 23. Natural gas heating is mainly concentrated from November to April, and from November to January, the average daily heat supply shows an upward trend. From January to April, the average daily heat supply gradually decreases, and the overall is related to the season, which is in line with the actual situation. The average daily heat supply in January is the largest at 744.7 kW. The average annual heat supply of the residential building is 46 kW. The annual cumulative heating unit area index of the residential building and the household average index are 26.6 kW·h/m2and 2 099.5 kW·h/household respectively. The annual cumulative natural gas load unit area index is 3.73 m3/m2, and the annual cumulative natural gas load average household index is 295 m3/household.

Keywords: south heating; natural gas heating; residential building; natural gas load; intermittent heating

MeasuresforUrbanGasEnterprisestoDealwithNaturalGasEnergyMeteringandPricing

YUAN Qing, CUI Enhuai, JIANG Zhaowei, GAO Ran

Abstract： Under the background of full implementation of energy metering and pricing in the upstream, it is an inevitable trend for urban gas to change from volume metering and pricing to energy metering and pricing. However, the existing terminal metering equipment and pricing model of urban gas enterprises are difficult to directly realize energy metering and pricing. In a period of time, the energy measurement methods for urban gas enterprises and end-users will be local energy measurement method and variable assignment method. The local energy measurement method is used for energy measurement of large users. Some qualified medium users were selected and the metering device was modified as a pilot of local energy measurement. For small users, especially resident users, variable assignment method is adopted.

Keywords: urban gas enterprise; natural gas; energy metering and pricing; volumetric metering and pricing

ThoughtsonNaturalGasGasificationofTownsandVillagesinShaanxiProvince

HAN Yi, YANG Yifan, LI Junlong

Abstract： The difficulties in implementing the gasification of towns and villages in Shaanxi Province are analyzed. The practices and achievements in implementing the gasification of towns and villages are introduced, and recommendations are given.

Keywords: gasification of towns and villages; rural gas; rural revitalization

GasSourceandProcessingUtilizationStudyonEffectofMetalIonsonMDEA+MEACompoundAmineSolutionFoaming

ZHANG Yizhi, YU Zehua, YANG Chaojiang, ZHOU Junyi, TANG Jianfeng

Abstract： Using the airflow method, a set of experimental equipment for foaming characteristics of amine solution was built to study the foaming height and defoaming time of MDEA+MEA compound amine solution after adding Fe3+, Fe2+, Ca2+, Mg2+, Na+and K+ions. The effect of metal ion mass concentration on foaming characteristics of the compound amine solution and foam stability is analyzed. It is found that Fe3+and Mg2+have the greatest influence on the foaming characteristics of the compound amine solution in the range of the experimental study mass concentration, the foaming process of the compound amine solution is obviously promoted, and the foam stability is enhanced. The foaming characteristics and foam stability of the compounded amine solution are less affected by the changes in the mass concentration of Fe2+and K+. Ca2+and Na+can reduce the foaming height, shorten the defoaming time, and inhibit foaming.

Keywords: natural gas decarbonization; compound amine solution; metal ion; foaming characteristics

BuildingGasSupplyDevelopmentofAuxiliaryQuotationToolofGasPipelineProjectforSmallCommercialUsers

LI Xinqiang, WU Zexin

Abstract： By combing the current quotation process of gas pipeline projects for small commercial users, the process optimization direction is determined. Based on VBA technology, an auxiliary quotation tool for gas pipeline projects for small commercial users is developed on Excel software. In view of actual cases, the reference quotation compiled under the current process and generated by the auxiliary quotation tool is compared, and the superiority of the auxiliary quotation tool is highlighted in the aspect of time consumption.

Keywords: commercial user; auxiliary quotation tool; EXCEL software; VBA technology

GasEquipmentandMaterialsTechnicalAnalysisofElectronicTemperature-PressureCorrectionMembraneGasMeter

LIANG Yongzeng

Abstract： The electronic temperature-pressure correction membrane gas meter is divided into two types according to the electronic temperature-pressure volume correction technology adopted: mechanical metering-electronic indirect metering temperature-pressure volume correction and electronic indirect metering temperature-pressure volume correction. The electronic indirect metering temperature-pressure volume correction is divided into pure electronic indirect metering temperature-pressure volume correction and electronic indirect metering temperature-pressure volume correction with mechanical secondary indirect measurement. The basic principle and temperature-pressure volume correction process of the three electronic temperature-pressure volume correction membrane gas meters are explained. The numerical value of the mechanical counter of the electronic indirect metering temperature-pressure volume correction with mechanical secondary indirect measurement is the result of human intervention, and has no substantial meaning, and there is a risk of affecting the accuracy of gas meter measurement. Membrane gas meter electronic temperature-pressure volume correction should use mechanical metering-electronic indirect metering temperature-pressure volume correction technology or pure electronic indirect metering temperature-pressure volume correction technology, and the measurement data of the two can be used as the basic data of trade settlement.

Keywords: membrane gas meter; electronic temperature-pressure correction; metering; temperature; pressure

GasInformatizationDataStandardizationConstructionofGasPipelineIntegrityManagement

JIAO Jianying, JIANG Feng, WANG Songmei, MA Xuqing, MA Bin, LIU Hui

Abstract： The problems existing in the integrity management of gas pipeline are analyzed, and the way of data standardization construction is explored. There are problems such as data management system and lack of data standardization and so on in gas pipeline integrity management. Data standardization construction can start with the establishment of data standards, the establishment of a life-cycle data framework and the establishment of data governance system.

Keywords: gas pipeline; integrity management; data standardization

GasEnterpriseManagementCalculationMethodofInspectionArrivalRateofUrbanPipeNetworkBasedonGridMatrix

ZHOU Yajuan, LI Tingyan

Abstract： The calculation method of the inspection arrival rate of existing urban pipe network and the existing problems are introduced. An accurate calculation method of the inspection arrival rate of urban pipe network based on grid matrix is proposed. The calculation steps, advantages and application effects of the method are discussed.

Keywords: urban pipe network; inspection; arrival rate; grid matrix