A time series model is used in this paper to describe the progress of circulating direct condensation heat recovery of the compound condensing process (CCP) which is made of two water cooling condensing processes in s...A time series model is used in this paper to describe the progress of circulating direct condensation heat recovery of the compound condensing process (CCP) which is made of two water cooling condensing processes in series for a centrifugal chiller in the paper. A finite-time thermodynamics method is used to set up the time series simulation model. As a result, an upper bound of recoverable condensation heat for the compound condensing process is obtained which is in good agreement with experimental result. And the result is valuable and useful to optimization design of condensing heat recovery.展开更多
To a kind of centrifugal water chiller with R22 and about 1 745 kW of cooling capacity,a heat exchanger was added between the outlet of compressor and original condenser to get part of or all the condensing heat.Conde...To a kind of centrifugal water chiller with R22 and about 1 745 kW of cooling capacity,a heat exchanger was added between the outlet of compressor and original condenser to get part of or all the condensing heat.Condensing heat can be recovered by compound condensing method,which adopts air-cooling model +water-cooling model or water-cooling model +water-cooling model at the condensing side of the system.By exergy analysis and experiment research on compound condensing heat recovery of centrifugal chiller,the results are obtained that the capability of the whole system increases,the energy efficiency ratio(EER)becomes 3.2～5.0 from 2.2～3.4,which implies the EER increases about 1.0～1.5,the exergy efficiency increases about 10%,and the chiller runs more stably after reformation.展开更多
The relative permeability curve has been measured with simulation oil (refined oil) and gas (nitrogen or air) at room temperature and a lowpressure, both of which are very important parameters for depicting the flow ...The relative permeability curve has been measured with simulation oil (refined oil) and gas (nitrogen or air) at room temperature and a lowpressure, both of which are very important parameters for depicting the flow of fluid through porous media in a hydrocarbon reservoir. This basic measurement is often applied in exploitation evaluation, but the underground conditions with high temperature and pressure, and the phase equilibrium of oil and gas, are not taken into consideration when the relative permeability curve is tested. There is an important theoretical and practical sense in testing the diphase relative permeability curve of the equilibrium of oil and gas under the conditions of high temperature and pressure. The test method for the relative permeability curve is proposed in this paper. The relative permeability of the equilibrium of oil and gas and the standard one are tested in two fluids, and the differences between these two methods are stated. The research results can be applied to the simulation and prediction of CVD in long cores and then the phenomenon can better explain that the recovery of condensate gas rich in condensate oil is higher than that of CVD test in PVT. Meanwhile, the research shows that the relative permeability curve of equilibrium oil and gas is sensitive to the rate of exploitation, and the viewpoint proves that an improved gas recovery rate can properly increase the recovery of condensate oil.展开更多
The recovery factor from tight gas reservoirs is typically less than 15%, even with multistage hydrauhc tractunng stimulation. Such low recovery is exacerbated in tight gas condensate reservoirs, where the depletion o...The recovery factor from tight gas reservoirs is typically less than 15%, even with multistage hydrauhc tractunng stimulation. Such low recovery is exacerbated in tight gas condensate reservoirs, where the depletion of gas leaves the valuable condensate behind. In this paper, three enhanced gas recovery （EGR） methods including produced gas injection, CO2 injection and water injection are investigated to increase the well productivity for a tight gas condensate reservoir in the Montney Formation, Canada. The production performance of the three EGR methods is compared and their economic feasibility is evaluated. Sensitivity analysis of the key factors such as primary production duration, bottom-hole pressures, and fracture conductivity is conducted and their effects on the well production performance are analyzed. Results show that, compared with the simple depletion method, both the cumulative gas and condensate production increase with fluids injected. Produced gas injection leads to both a higher gas and condensate production compared with those of the CO2 injection, while waterflooding suffers from injection difficulty and the corresponding low sweep efficiency. Meanwhile, the injection cost is lower for the produced gas injection due to the on-site available gas source and minimal transport costs, gaining more economic benefits than the other EGR methods.展开更多
In this study, the concept of a new seawater desalination method and equipment using liquid columns of seawater and desalinated fresh water, decompression boiling and evaporation, condensation, and recovery of condens...In this study, the concept of a new seawater desalination method and equipment using liquid columns of seawater and desalinated fresh water, decompression boiling and evaporation, condensation, and recovery of condensation latent heat are proposed. The equipment consists of seawater and freshwater columns approximately 10 m high with top spaces. The pressure of the top space, the evaporation and condensation area, of the seawater column, for example, is reduced approximately 30 mmHg (abs.) using the seawater column, after which it is heated from the general seawater temperature of 25°C to 30°C to boil and evaporate the seawater. The vapor is cooled by the seawater at approximately 25°C in a heat exchanger, and then, it is condensed and sent to the fresh water column. At this time, the condensation latent heat is recovered to preheat the newly flowing seawater. The evaporation or condensation rate, namely, the production rate of freshwater, by the new desalination equipment is also estimated by the results of the existing quadruplex effect vacuum evaporator used in the salt production industry. This new desalination method and its associated equipment also can be used to purify polluted water and waste water.展开更多
This paper presents a frame figure of the recovery system concerning waste heat of steam condensate. When steam phase changes into liquid state in the condenser, the heat equilibium equation, gas state equation, mass ...This paper presents a frame figure of the recovery system concerning waste heat of steam condensate. When steam phase changes into liquid state in the condenser, the heat equilibium equation, gas state equation, mass flow calculating equation of the jet steam and incondensable gas equation are established. The coupling function between condensate unit and recovery pump of the hot condensate with ejector is studied. The paper sets up the fluid continuity equation, heat equilibium equation and efficiency equation of the ejector and points out the technical key how the prevent hot condensate change into steam phase. When fluid passes from circulation loop through pump to export, the energy equations are obtained here. At last, signal figure of the applied examples are given and settle the techanical questions of the jet system are discussed.展开更多
A vacuum membrane distillation(VMD)process with permeate fractional condensation on membrane downstream has been developed for simultaneous recovery of phosphorus and nitrogen from liquid digestate.The polytetrafluoro...A vacuum membrane distillation(VMD)process with permeate fractional condensation on membrane downstream has been developed for simultaneous recovery of phosphorus and nitrogen from liquid digestate.The polytetrafluoroethylene(PTFE)membrane flux could reach 6000 g·m-2·h-1 with the rejection efficiency of total phosphorus(TP)over 0.99,under the condition of flowrate being 120 L·h-1 and temperature being 40°C.Membrane fouling occurred with a film of organics and microorganism deposited on the surface of the membrane.Membrane flux could be reversed after the membrane was rinsed by water.Higher feed temperature and flowrate could improve the membrane flux,while hardly affect the rejection efficiency of total phosphorus.The concentration of TP could reach 1600 mg·L-1 after membrane distillation,which is about 5 times of that in initial liquid digestate.On the downstream of the membrane,some of the permeate vapor was condensed under the vacuum condition and most of water was collected here.The remaining vapor enriched with total nitrogen(TN)was compressed and pumped to the atmospheric condition to condense.The TN concentration in atmospheric condensate was as high as 7000 mg·L-1 with the process separation factor for ammonia being enhanced to 114.展开更多
The paper shows a method of designing a heat exchanger recovering heat from the condensation of water vapour contained in flue gases. A heat exchanger condenses water vapour and SO2 （sulphur dioxide） in the presence...The paper shows a method of designing a heat exchanger recovering heat from the condensation of water vapour contained in flue gases. A heat exchanger condenses water vapour and SO2 （sulphur dioxide） in the presence of inert gases （CO2, CO, N2, O2） contained in flue gases. A mathematical model and a sample design of a heat exchanger were presented. The heat exchange is capable of recovering from a dozen or so to several dozen percent of heat from flue gases escaping into the atmosphere. A second advantage of the heat exchanger is the possibility to reduce the emissions of SO2 considerably. Depending on the parameters, it can be even a sevenfold reduction in the emissions. The main mathematical tool used for designing the condensing heat exchanger is the Colburn-Hougen method. The authors omitted that part of the method which requires iterative calculations. The Mollier diagram was used instead.展开更多
文摘A time series model is used in this paper to describe the progress of circulating direct condensation heat recovery of the compound condensing process (CCP) which is made of two water cooling condensing processes in series for a centrifugal chiller in the paper. A finite-time thermodynamics method is used to set up the time series simulation model. As a result, an upper bound of recoverable condensation heat for the compound condensing process is obtained which is in good agreement with experimental result. And the result is valuable and useful to optimization design of condensing heat recovery.
文摘To a kind of centrifugal water chiller with R22 and about 1 745 kW of cooling capacity,a heat exchanger was added between the outlet of compressor and original condenser to get part of or all the condensing heat.Condensing heat can be recovered by compound condensing method,which adopts air-cooling model +water-cooling model or water-cooling model +water-cooling model at the condensing side of the system.By exergy analysis and experiment research on compound condensing heat recovery of centrifugal chiller,the results are obtained that the capability of the whole system increases,the energy efficiency ratio(EER)becomes 3.2～5.0 from 2.2～3.4,which implies the EER increases about 1.0～1.5,the exergy efficiency increases about 10%,and the chiller runs more stably after reformation.
基金This paper was subsidized by the 15th National key Sci-Tech Project (NO.2001BA605A02-04-01)
文摘The relative permeability curve has been measured with simulation oil (refined oil) and gas (nitrogen or air) at room temperature and a lowpressure, both of which are very important parameters for depicting the flow of fluid through porous media in a hydrocarbon reservoir. This basic measurement is often applied in exploitation evaluation, but the underground conditions with high temperature and pressure, and the phase equilibrium of oil and gas, are not taken into consideration when the relative permeability curve is tested. There is an important theoretical and practical sense in testing the diphase relative permeability curve of the equilibrium of oil and gas under the conditions of high temperature and pressure. The test method for the relative permeability curve is proposed in this paper. The relative permeability of the equilibrium of oil and gas and the standard one are tested in two fluids, and the differences between these two methods are stated. The research results can be applied to the simulation and prediction of CVD in long cores and then the phenomenon can better explain that the recovery of condensate gas rich in condensate oil is higher than that of CVD test in PVT. Meanwhile, the research shows that the relative permeability curve of equilibrium oil and gas is sensitive to the rate of exploitation, and the viewpoint proves that an improved gas recovery rate can properly increase the recovery of condensate oil.
基金funding from Natural Sciences and Engineering Research Council of Canada (NSERC) for this researchsupport from the University of Calgary Beijing Research Site, a research initiative associated with the University of Calgary Global Research Initiative in Sustainable Low Carbon Unconventional Resources, the Kerui Group, and the Mitacs Accelerate program
文摘The recovery factor from tight gas reservoirs is typically less than 15%, even with multistage hydrauhc tractunng stimulation. Such low recovery is exacerbated in tight gas condensate reservoirs, where the depletion of gas leaves the valuable condensate behind. In this paper, three enhanced gas recovery （EGR） methods including produced gas injection, CO2 injection and water injection are investigated to increase the well productivity for a tight gas condensate reservoir in the Montney Formation, Canada. The production performance of the three EGR methods is compared and their economic feasibility is evaluated. Sensitivity analysis of the key factors such as primary production duration, bottom-hole pressures, and fracture conductivity is conducted and their effects on the well production performance are analyzed. Results show that, compared with the simple depletion method, both the cumulative gas and condensate production increase with fluids injected. Produced gas injection leads to both a higher gas and condensate production compared with those of the CO2 injection, while waterflooding suffers from injection difficulty and the corresponding low sweep efficiency. Meanwhile, the injection cost is lower for the produced gas injection due to the on-site available gas source and minimal transport costs, gaining more economic benefits than the other EGR methods.
文摘In this study, the concept of a new seawater desalination method and equipment using liquid columns of seawater and desalinated fresh water, decompression boiling and evaporation, condensation, and recovery of condensation latent heat are proposed. The equipment consists of seawater and freshwater columns approximately 10 m high with top spaces. The pressure of the top space, the evaporation and condensation area, of the seawater column, for example, is reduced approximately 30 mmHg (abs.) using the seawater column, after which it is heated from the general seawater temperature of 25°C to 30°C to boil and evaporate the seawater. The vapor is cooled by the seawater at approximately 25°C in a heat exchanger, and then, it is condensed and sent to the fresh water column. At this time, the condensation latent heat is recovered to preheat the newly flowing seawater. The evaporation or condensation rate, namely, the production rate of freshwater, by the new desalination equipment is also estimated by the results of the existing quadruplex effect vacuum evaporator used in the salt production industry. This new desalination method and its associated equipment also can be used to purify polluted water and waste water.
文摘This paper presents a frame figure of the recovery system concerning waste heat of steam condensate. When steam phase changes into liquid state in the condenser, the heat equilibium equation, gas state equation, mass flow calculating equation of the jet steam and incondensable gas equation are established. The coupling function between condensate unit and recovery pump of the hot condensate with ejector is studied. The paper sets up the fluid continuity equation, heat equilibium equation and efficiency equation of the ejector and points out the technical key how the prevent hot condensate change into steam phase. When fluid passes from circulation loop through pump to export, the energy equations are obtained here. At last, signal figure of the applied examples are given and settle the techanical questions of the jet system are discussed.
基金supported by the Fundamental Research Funds for the Central Universities(No.20822041B4013)Key Laboratory of Development and Application of Rural Renewable Energy,Ministry of Agriculture and Rural Affairs,China(No.18H0491)。
文摘A vacuum membrane distillation(VMD)process with permeate fractional condensation on membrane downstream has been developed for simultaneous recovery of phosphorus and nitrogen from liquid digestate.The polytetrafluoroethylene(PTFE)membrane flux could reach 6000 g·m-2·h-1 with the rejection efficiency of total phosphorus(TP)over 0.99,under the condition of flowrate being 120 L·h-1 and temperature being 40°C.Membrane fouling occurred with a film of organics and microorganism deposited on the surface of the membrane.Membrane flux could be reversed after the membrane was rinsed by water.Higher feed temperature and flowrate could improve the membrane flux,while hardly affect the rejection efficiency of total phosphorus.The concentration of TP could reach 1600 mg·L-1 after membrane distillation,which is about 5 times of that in initial liquid digestate.On the downstream of the membrane,some of the permeate vapor was condensed under the vacuum condition and most of water was collected here.The remaining vapor enriched with total nitrogen(TN)was compressed and pumped to the atmospheric condition to condense.The TN concentration in atmospheric condensate was as high as 7000 mg·L-1 with the process separation factor for ammonia being enhanced to 114.
文摘The paper shows a method of designing a heat exchanger recovering heat from the condensation of water vapour contained in flue gases. A heat exchanger condenses water vapour and SO2 （sulphur dioxide） in the presence of inert gases （CO2, CO, N2, O2） contained in flue gases. A mathematical model and a sample design of a heat exchanger were presented. The heat exchange is capable of recovering from a dozen or so to several dozen percent of heat from flue gases escaping into the atmosphere. A second advantage of the heat exchanger is the possibility to reduce the emissions of SO2 considerably. Depending on the parameters, it can be even a sevenfold reduction in the emissions. The main mathematical tool used for designing the condensing heat exchanger is the Colburn-Hougen method. The authors omitted that part of the method which requires iterative calculations. The Mollier diagram was used instead.
