Condensate Flow Rate Research Articles

Методические аспекты анализа факторов, влияющих на испарение газоконденсата при подводных выбросах

The process of evaporation of gas condensate during emergency blowout of an underwater well has been studied insufficiently. The influence of various factors on the size of the zone of intense evaporation of gas condensate during the blowout of a shallow gas condensate well requires detailed consideration. In this paper, the researchers, using mathematical modeling, have analyzed this effect for wells with parameters characteristic of the Russian Arctic region. They have performed the calculations using the SPILLMOD model and the Lagrangian element evolution model. A significant dependence of the gas outlet area size and the gas blowout size on the sea surface on the values of the gas plume involvement parameter in the model has been revealed, and at the same time a weak dependence of the size of the zone of intense evaporation of gas condensate on this parameter. The values of the mass flow rate of gas condensate in the discharge, as well as its fractional composition, have a noticeably greater effect.

Theoretical modeling of process heat transfer mechanism in U-shaped molten salt heat exchanger

U-shaped tube molten salt heat exchanger (MSHE) plays an important role for further improving peak shaving capacity of coal-fired unit (CFU) coupled extraction thermal storage system (ETSS). Nevertheless, existing experimental approach cannot reveal process heat transfer characteristics (HTCs) of MSHE. Meanwhile, investigation exploring factors restricting heat transfer enhancement for MSHE in theory is still vacant. In this paper, a theoretical method for MSHE was developed to determine process mechanism of heat transfer to capture perspective of enhanced heat transfer. Heat transfer performance of U-tube MSHE was theoretically unpacked. Deliberating work was executed with inlet water flow rate of 69–139 kg/s, water temperature of 120–170 °C, salt flow rate of 28–58 kg/s and salt temperature of 350–400 °C. Whereupon, the process mechanism of heat transfer inside MSHE was obtained with redeeming lack of theoretical exploration.Research shows, total HTC respectively increases by 2.57 and 1.88 W/(m2·°C) with 10 °C increasing of molten salt inlet temperature (MSIT) and 14 kg/s ascension in condensate flow rate (CFR). It is signified thermal resistance of countercurrent section of MSHE mainly involving HTCs of MSHE with increment of MSIT and CFR. Such privileged sites are main factor restricting heat transfer enhancement. Moreover, total HTC respectively increases by 2.1 and 21.84 W/(m2·°C) with 10 °C upgrading in condensate inlet temperature (CIT) and 6 kg/s increment in molten salt flow rate (MSFR). Contrary to augmenting MSIT and CFR, HTCs changing of MSHE with CIT alteration and MSFR preferment mainly attributed to downstream section and inlet position of MSHE. Meanwhile, it is discovered significant impact is generated for HTCs of MSHE with specific heat changing in molten salt. Furthermore, it was proven that Bell method is suitable for calculating HTC of molten salt on shell side in U-shaped tube MSHE. The research contents in present work can provide reliable basis for optimal design and application of U-tube MSHE in CFU.

Sustainable wastewater recovery system employing geothermal energy – Performance and feasibility study

In this study, a sustainable wastewater recovery system employing geothermal energy has been proposed. The efficiency of the suggested sustainable system has been simulated using heat transfer. Then, component-wise validation has been carried out with the existing data available in the literature wherever applicable and estimated an error of ± 8 %. The proposed sustainable system’s parametric and performance analyses have employed the developed vapor. From the parametric study, it is observed that hot spring temperatures have a significant influence on sustainable systems. Further, through performance investigation, it is understood that low dam/river/sea water temperatures and enhancing the water condenser effectiveness and flow rate ratio simultaneously improve the system performance. For different climatic regions of India, explored the feasible geothermal hotspots near dams/rivers/seawater and analyzed that among the hot and dry, hot and humid, composite and cold regions, the proposed sustainable system is best suitable at a composite region with a maximum possible water extraction/freshwater generation rate of 0.78 L/h for the given specifications and operating range. Moreover, it is assessed that hot spring temperature is the deciding factor for sustainable system performance in different climatic regions. Further, the current study can be used as a reference for understanding the phenomenon of potential geothermal hotspots for wastewater recovery in various climatic areas

Computational boundary improvement and performance optimization of the flue gas waste heat cascade utilization system of the ultra-supercritical 1000 MW generator set

Abstract There is no uniform performance test rule and standard calculation method for efficiency improvement of a system that utilizes waste heat from flue gas and it is mainly carried out through turbine parameters, without considering boiler system performance. Given the above problem, in this paper, the steam turbine, boiler and waste heat from the flue gas step-up utilization system are calculated by establishing a thermal model of ultra-supercritical secondary reheating 1000 MW unit. At the same time, unit design data and field performance test results are used for verification. Analysis comparing simulation outcomes with experimental data revealed that the discrepancies in the heat consumption rate per unit, the efficiency of the boiler, and the rate of coal consumption for power generation peaked at a marginal variance of 0.2%. The optimum operating parameters of the system for low-grade flue gas recovery in a cascading manner are obtained through variable operating condition calculations. The optimum value of high-pressure bypass feed-water flow rate is 52 kg/s at 970 MW operating condition. At the same time, the difference between high-pressure bypass effluent and high plus effluent temperatures should be controlled to be close to 0°C, and the optimal value of low-pressure bypass condensate flow rate is 53 kg/s. As the flow of flue gas in the bypass increases, the efficiency of heat exchange in the bypass economizer also increases, resulting in greater absorption of heat in the utilization apparatus for flue gas waste heat, leading to a more effective energy-saving outcome. However, it is necessary to regulate the temperature of both the primary and secondary air to levels that exceed the minimum requirements for the safe functioning of the coal mill.

Wet cooling of air on plate finned tube heat exchangers

The objective of this paper is to provide the reliable calculation procedure for determining heat and mass flow rates for plate finned tube heat exchangers in dehumidification regimes that can be used easily in engineering practice. For this purpose, the experiments are conducted on two heat exchangers, and datasets for six more heat exchangers are used from literature. Comprehensive database is established with total of 637 sets of data, and it gathers 365 new measurement sets and 272 sets from open literature. The new calculation procedure predicts heat transfer rate and condensate flow rate where new methodology approach (based on the porous velocity, the ratio of characteristic surfaces and hydraulic diameter) is used. Predicted results show 5–10 % deviation for heat duty and up to 20 % for mass flow rate from experimental results, which is of importance to industrial practice.

Heavy hydrocarbon recovery with integration of turboexpander and JT valve from highly CO2-containing natural gas for gas transmission pipeline

Demand of natural gas is predicted to increase since many valuable products can be produced. Water and heavy hydrocarbon content are the key for gas pipeline facility. To meet requirement of natural gas transportation, dehydration unit (DHU) and hydrocarbon dew point control unit (DPCU) are necessary to avoid water and hydrocarbon condensation during transmission. The conventional dehydration technology, TEG contactor, can lower water content from 1,304 mg/m3 to 80.35 mg/m3 where the maximum limit of water content in natural gas is 97 mg/m3 to prevent hydrate formation. DPCU is installed to remove heavy hydrocarbon, especially C5+. Integration of JT valve and turboexpander was employed to obtain the low gas dew point. The hot gas stream that entered the JT valve was observed. The lower hot bypass gas was applied, the lower hydrocarbon dew point and the more condensate flowrate was achieved. The highest power generation can be gained at low hot gas flow ratio which also influenced the exit pressure and temperature of compressor. In pipeline simulation, the pressure and temperature drop occurred at the high hot gas rate. To examine the arrival condition, dew point curves were generated and showed that the limitation of hot gas flow ratio has to be below 0.6 to prevent heavy hydrocarbon condensation in pipeline.

Optimization of gas extraction of producing wells to increase the efficiency of condensate production

The article discusses ways to increase the efficiency of condensate production due to the optimal distribution of gas flows between producing wells. For a large number of wells, the solution of this problem becomes nontrivial and requires special methods of nonlinear optimization. The main aim of research is obtaining accurate solutions to the problem of optimizing condensate production using direct dependencies between gas and condensate production. The minimum set of reliable field information has been determined, which allows solving the problem of optimal distribution of gas production between wells at the maximum condensate flow rate. An optimization problem is formulated for this model. The conditions under which the initial problem is divided into a system of optimization subtasks for subgroups of wells are considered. By the method of pairwise optimization, analytical expressions were found for optimal ratios of gas flow rates in a group of wells. Based on the expressions obtained, an algorithm has been developed for the exact solution of the problem of short-term optimization of the well operation mode.

Possibilities Study of a Non-condensable Gas Exhaust System through the Condensate Injection Pipe at PLTP Wayang Windu

Wayang Windu Geothermal Power Plant, located in Pangalengan, Bandung regency, West Java with an installed capacity of 227 MWe has two units to generate electricity and deliver to the Jawa, Madura, and Bali grid. The steam extracted from the reservoir contains non-condensable gas of about 1-1.2% of total steam extracted, with the gas composition is CO2 92%, H2S 2%, NH3 0.1%, and residual gasses 4.9%. Possibilities study of a non-condensable gas exhaust through the condensate injection pipe was created as the efforts in the environmental conservation aspect for reducing carbon released to the atmosphere and reinjected back into the reservoir. This study was simulated in Wayang Windu Unit 2 by calculating the non-condensable gas flow rate from the gas removal system into the condensate injection pipe near of cooling tower blowdown power station area. The analysis result of this study indicates that the non-condensable gas requires a higher flow rate of condensate to dissolve the entire non-condensable gas, and may cause the slug flow pattern which would endanger the condensate pipeline system also destabilize the non-condensable gas exhaust operation process from the condenser through the gas removal system. To deal with this problem, the possibility of exhausting the non-condensable gas produced by the gas removal system can be alternated by flowing its non-condensable gas into a flash absorber system and converting its non-condensable gas into other eco-friendly products and power plant safe.

Experimental investigations of liquid immersion cooling for 18650 lithium-ion battery pack under fast charging conditions

In this study, a novel battery thermal management system (BTMS) based on FS49 is proposed and tested for cooling the cylindrical lithium-ion battery (LIB) module under fast charging conditions. Firstly, the temperature response of the battery module under 2 C and 3 C rates charging with forced air cooling (FAC) and liquid immersion cooling (LIC) is compared. The results indicate that the LIC has excellent heat dissipation performance, and the peak temperature of the module during 2 C and 3 C rates charging are reduced by 7.7 °C and 19.6 °C, respectively, compared with the FAC, while the corresponding cooling energy consumption of LIC is only 14.41% and 40.37% of the FAC. Meanwhile, the LIC embraces the advantages of minimizing the temperature non-uniformity in battery pack. The corresponding peak temperature difference of the module is just 1.1 °C and 1.2 °C, which is only 17.7% and 11.6% of that under FAC. Subsequently, the thermal management performance of the proposed LIC is investigated under conventional C rate discharging and different fast charging schemes. Finally, effect of condenser flow rate and cooling water temperature were investigated. This study demonstrates the application prospect of the LIC in the field of LIB fast charging.

Influence of operating conditions on in-tube vapour condensation heat transfer characteristics in the presence of noncondensable gases at high pressure

The in-tube vapour condensation heat characteristics in the presence of noncondensable gas at high pressures are experimentally validated with an error of 20%. Numerical simulations are then conducted to explore heat transfer characteristics at different operating pressures, wall surface temperatures and mass flow rates. The flow and heat transfer characteristics are thoroughly discussed and the buoyancy effects induce a secondary circulation altering flow patterns, changing the water film and heat transfer coefficient distribution. In addition, increasing operating pressures is found to reduce the wall heat transfer rate. Even though the flow pattern is significantly different caused by the increased gas mixture density, the total condensate flow rate is approximately the same at different operating pressures due to the same inlet conditions and temperature difference. The difference in the wall heat transfer rate is attributed to the change of latent heat of vapourisation and falling film at different pressures and is evident at high pressures. At the high temperature difference, a nonuniform film height towards the bottom is emerged, sweeping the condensate upward. Similarly, increasing the mass flow rate can also increase the total wall heat transfer rate and total condensate flow rate.

Theoretical and experimental investigations on the supercritical startup of a cryogenic axially Ω-shaped grooved heat pipe

The successful supercritical startup of a cryogenic grooved heat pipe is the premise for its normal operation, and the startup time determines the working efficiency of the payload. Based on this demand, a supercritical startup model of grooved heat pipe is established in the paper. The model applies more practical boundary conditions of the condensation section, without the need of knowing the temperature change of condenser in advance. With known performance curve of the cryocooler, the startup performance of heat pipe can be predicted, including the temperature distribution, startup time, etc. The predicted results by the model showed good agreement with the startup experiment results of the cryogenic grooved heat pipe. Additionally, the effects of different condenser lengths and structural parameters on the startup of heat pipe were analyzed by using the model. The results show that longer condenser length, larger groove diameter can accelerate the flow rate of condensate and the startup process. The influence of the groove depth to width of an Ω-shaped grooved heat pipe and a trapezoidal grooved heat pipe was also compared. This model provides a theoretical basis for the design and optimization of cryogenic grooved heat pipe.

Estimation of the Pure Condensate Flow Rate in the Starting Range in the Startup to the Minimum Controlled Power Level after the Activation of Emergency Protection

Estimation of the Pure Condensate Flow Rate in the Starting Range in the Startup to the Minimum Controlled Power Level after the Activation of Emergency Protection

Optimization of Condensate Transfer Pump in the Hydrocarbon Condensate Stabilization Unit of Natural Gas Liquefaction Plant – An Industrial Case

PT. Badak NGL is a commercial LNG producer located in Bontang, Indonesia. In recent years, the decline in LNG production of PT. Badak NGL results in a lower hydrocarbon condensate flow rate. To prevent power losses since its pump operated at below rating, a new operation scheme was proposed. This new scheme adjusts the way of pump is operated without any alteration in terms of pump characteristics. Three pumps operated intermittently for 8 hours per day at a maximum flow rate. The pump power consumption was calculated based on electric current data monitored relay panel. The results show that the pump energy saved by 60% with the absolute value of annual energy efficiency of 957.7 MWh. This study contributes to reducing the greenhouse effect by 412 tons eq CO and the annual production cost of around USD 130,000. The new scheme reliability examines by evaluating pump vibration, pump performance, hydrocarbon condensate quality, and condensate tank liquid level. The result shows that the pump’s vibration in the range of 0.21 in/sec with a steady winding temperature.

Performance study of transport membrane condenser using condensate water to recover water and heat from flue gas

Transport membrane condenser (TMC) is an effective equipment for water and heat recovery from flue gas exhausted by coal-fired power plants. Characteristic of cooling water source for TMC is crucial to design and performance of the device. Due to the high water quality and relatively large water flow rate, the condensate water from the unit condenser is a suitable water source. However, the water flow rate in related research exceeds the range of condensate water flow rate, and the results cannot be applied in this condition. Thus, we established a numerical model for performance study of TMC. The condensate water from the condenser of a 600 MW coal-fired power unit is adopted. The effects of structural and operating parameters on the performance of TMC are investigated, and the technical and economic analysis is conducted. Results show that series connection of membrane modules is more suitable than parallel connection for engineering applications. Moreover, the number of transverse rows should be larger than 60 by comprehensively considering heat and water recovery performance and flow resistance. Due to the high benefit of recovered heat, the maximum payback period is 1.68 years. This study provides theoretical support for the engineering application of TMC using condensate water as the cooling water source.

Effect of condensate flow rate, surface tension, density and vapor velocity on condensate retention of wire wrapped tubes

Simulated condensation has been conducted on three wire wrapped tubes having same root diameter but different fin spacing of 1.5 mm, 2 mm, and 2.5 mm. Different fluids (ethanol, ethylene-glycol, and water) are used for condensation by providing them to the tubes through tiny holes in inter-fin spacing on the top of the surface of tubes. The major parameters are to be controlled in this research are fin spacing, vapor velocity, condensate flow rate and ratio of surface tension density of the fluid. Obtained results show that flooding angle (calculated from the top of the tube to the level where fluid fills the fin) rises by increasing fin spacing. Also, retention angles increase by reducing ratio of surface tension density of fluid. Acute flooding angles at zero air velocity and zero flow rate, elevates by increasing air velocity. However, obtuse flooding angles at static conditions drop by reducing air velocity. An interesting result is obtained regarding retention angle which remains almost even for the higher condensation flow rates until the tube gets inundated with condensation. Moreover, critical flow rates for all the tubes against using different working fluids are measured. Results obtained for static conditions have good correspondence with already available authentic data for flooding angle. Pictures showing condensate retention angles have been included in this paper.

Two-phase spray cooling for high ambient temperature data centers: Evaluation of system performance

A lab-scale spray cooled rack system with a server and simulated heaters, operating with near-ambient temperature coolant of approximately 30 °C, was developed for data center cooling application. This system has significant energy saving potential as it eliminates the need for a chiller unit, which is usually necessary in conventional air-cooling schemes. The system was designed to dissipate a maximum heat load of 5.6 kW. Despite its higher operating temperature, our investigation shows that the spray cooled system leads to better cooling performance of the microprocessors as compared to conventional air-cooling scheme. A durability study for more than 40 h of cumulative intermittent operation showed no degradation in system performance when operated at high chamber temperature conditions (>35 ℃). The thermal performance of the spray cooled system and the effects of parameters such as spray nozzle flow rate, condenser fan power, condenser flow rate and heat loads were systematically characterized. It is found that the thermal performance of the simulated heaters is mainly affected by the spray nozzle flow rate, while the condenser fan power and condenser cooling water flow rate strongly affect the condensation rate and are, therefore, critical parameters for spray chamber pressure control. In summary, this work demonstrates the possibility of employing the newly developed spray cooled system for the thermal management of high-performance servers of data centers in tropical climates and identified key operating parameters that are useful for the design, operation and implementation of this system.

Experimental study of a hybrid solar thermoelectric generator energy conversion system

The development of renewable energy technologies to take advantage of clean energy sources, such as solar, is crucial for sustainability. Here, we show a hybrid solar thermoelectric (HSTE) concept that simultaneously recovers heat from the sun with a thermosyphon and generates electricity with a thermoelectric generator (TEG) via the Seebeck effect. In this work, we experimentally demonstrated a relatively low-temperature HSTE prototype that combines a cartridge heater (to emulate the sun), a TEG to generate electricity, and a thermosyphon. This thermosyphon consists of three zones: an evaporator, an adiabatic region, and a condenser. The TEG was located between the heater and the evaporator. The thermosyphon was used to maintain constant the low-temperature face of the TEG and to recover heat in the condenser zone. A thermal resistance model was developed to understand the HSTE. Our model shows good agreement with the experimental data and guides the further development of the system. To evaluate the technical feasibility and performance of the HSTE, we characterized the HSTE by measuring the temperatures, condenser flow rate, voltage, and current under 72 different experimental conditions. We reported an electrical power of up to 96 mW and a recovered heat up to 68.18 W, when 118 W were supplied through the cartridge heater. Deionized water was the working fluid showing a higher electrical power generation than a 40% ethylene glycol solution.

Optimization of Hydrodistillation of Rosemary Essential Oil

Extraction of essential oil from Algerian rosemary leaves is carried out by means of a hydro-distillation process. The important operating parameters such as extraction time, condensation flow rate and water/solid plant material ratio, have been investigated. The highest yield value was 1.92% and was obtained for a water/plant ratio, a condensate flowrate, and extraction time of 20, 4.51ml/min and 120 min, respectively. The essential oil components have been identified using the GCMS analysis which show camphor as the major ingredient, followed by camphene, α-pinene and 1,8-cineole. The results have been compared with those obtained using a supercritical carbon dioxide extraction process, which has shown to be more much better quantitatively and qualitatively.

Understanding and modeling of gas-condensate flow in porous media

Well deliverability impairment due to liquid dropout inside gas-condensate reservoirs below dew-point pressure is a common production problem. The operating conditions and the thermodynamic properties of the condensate govern the production performance of this type of reservoir. Modeling condensate production using analytical, semi-analytical or empirical formula for quick assessment of reservoir performance is a complicated method due to the complex thermodynamic behavior. The objective of this study is to provide a fundamental understanding of the flow and thermodynamics of gas-condensate fluid to develop tools for the production prediction. The prior developments of flow modeling of gas-condensate are briefly reviewed. The multi-phase flow and the depletion stages during production are discussed. Each component of pseudo-pressure calculations to determine the condensate flow rate is explained. Thermodynamic properties and laboratory experiment relevant to the flow of condensate are also explored. Pressure-volume-temperature properties such as two-phase envelope, constant composition expansion and constant volume depletion are demonstrated for three different gas-condensate fluids namely lean, intermediate and rich. This article is also useful for future developments of the production model for a gas-condensate under various operational and completion scenarios such as horizontal wells and hydraulic fractures in tight formations. Cited as : Panja, P., Velasco, R., Deo, M. Understanding and modeling of gas-condensate flow in porous media. Advances in Geo-Energy Research, 2020, 4(2): 173-186, doi: 10.26804/ager.2020.02.06

Modeling, calibration, and sensitivity analysis of direct expansion AHU-Water source VRF system

The term variable refrigerant flow (VRF) refers to the ability of a system to control the amount of refrigerant flow rate, which enables the use of many evaporators (indoor units) of differing capacities and configurations connected to a single condensing unit. The feature offers individualized comfort control and simultaneous heating and cooling in different zones. In this study, a performance prediction model of a DX AHU (direct expansion air handling unit)-water source VRF heat pump system was constructed based on EnergyPlus, MATLAB and BCVTB using actual measured data. Advanced control logic using an EMS function was used in EnergyPlus for outdoor unit modeling, while prediction models for a cooling tower, boiler and pump were constructed in Matlab. In order to predict the model’s quantitative energy consumption, performance curves and power consumption were calculated. The calculations were checked by comparing them with actual data and the performance curves were then calibrated. The validity test results after the calibrations showed reliable results with a Cv(RMSE) of 14.5%. Based on these results, we performed a sensitivity analysis of the DX AHU-water source VRF system’s cooling energy according to the AHU discharge air temperature, refrigerant evaporative temperature and condenser fluid temperature and flow rate.