Study on the thermal characteristics of crude oil batch pipelining with differential outlet temperature and inconstant flow rate

Exploring the wax removal process by numerical simulation is beneficial for guiding field operations. In this paper, enthalpy-porosity and volume of fluid (VOF) methods were adopted to simulate the melting process of wax in the crude oil gathering pipeline. The melting patterns and liquid fraction of the wax were used to validate the mathematical model. The results show that the wax melts quickly before the liquid fraction reaches 80%, while the remaining 20% melts very slowly. Since the water with higher density sinks to the lower part of the pipeline, the wax in the lower part of the pipeline melts first, while the wax in the upper part of the pipeline melts slowly. The water temperature and flow rate disproportionately affect the melting process. Increasing the water temperature and flow rate can accelerate the melting process, but the effects on shortening the melting time of wax gradually decrease. Increasing the flow rate, the heat transfer rate and the melting rate are increasing progressively, the change of flow rate also affects the outlet temperature of the pipeline.

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Design and thermal characteristic analysis of motorized spindle cooling system

Advances in Mechanical Engineering ◽

10.1177/16878140211020878 ◽

2021 ◽

Vol 13 (5) ◽

pp. 168781402110208

Author(s):

Yuan Zhang ◽

Lifeng Wang ◽

Yaodong Zhang ◽

Yongde Zhang

Keyword(s):

Flow Rate ◽

High Speed ◽

Thermal Deformation ◽

Cooling System ◽

Thermal Characteristic ◽

Water Flow Rate ◽

Thermal Characteristics ◽

Characteristic Analysis ◽

Motorized Spindle ◽

Experiment And Simulation

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

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Role of Shearing Dispersion and Stripping in Wax Deposition in Crude Oil Pipelines

Energies ◽

10.3390/en12224325 ◽

2019 ◽

Vol 12 (22) ◽

pp. 4325

Author(s):

Zhihua Wang ◽

Yunfei Xu ◽

Yi Zhao ◽

Zhimin Li ◽

Yang Liu ◽

...

Keyword(s):

Crude Oil ◽

Flow Rate ◽

Critical Flow ◽

Wax Deposition ◽

Dominant Effect ◽

Critical Flow Rate ◽

Oil Pipelines ◽

Oil Flow ◽

Shearing Mechanism

Wax deposition during crude oil transmission can cause a series of negative effects and lead to problems associated with pipeline safety. A considerable number of previous works have investigated the wax deposition mechanism, inhibition technology, and remediation methods. However, studies on the shearing mechanism of wax deposition have focused largely on the characterization of this phenomena. The role of the shearing mechanism on wax deposition has not been completely clarified. This mechanism can be divided into the shearing dispersion effect caused by radial migration of wax particles and the shearing stripping effect caused by hydrodynamic scouring. From the perspective of energy analysis, a novel wax deposition model was proposed that considered the flow parameters of waxy crude oil in pipelines instead of its rheological parameters. Considering the two effects of shearing dispersion and shearing stripping coexist, with either one of them being the dominant mechanism, a shearing dispersion flux model and a shearing stripping model were established. Furthermore, a quantitative method to distinguish between the roles of shearing dispersion and shearing stripping in wax deposition was developed. The results indicated that the shearing mechanism can contribute an average of approximately 10% and a maximum of nearly 30% to the wax deposition process. With an increase in the oil flow rate, the effect of the shearing mechanism on wax deposition is enhanced, and its contribution was demonstrated to be negative; shear stripping was observed to be the dominant mechanism. A critical flow rate was observed when the dominant effect changes. When the oil flow rate is lower than the critical flow rate, the shearing dispersion effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. When the oil flow rate is higher than the critical flow rate, the shearing stripping effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. This understanding can be used to design operational parameters of the actual crude oil pipelines and address the potential flow assurance problems. The results of this study are of great significance for understanding the wax deposition theory of crude oil and accelerating the development of petroleum industry pipelines.

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Solar Field Output Temperature Optimization Using a MILP Algorithm and a 0D Model in the Case of a Hybrid Concentrated Solar Thermal Power Plant for SHIP Applications

Energies ◽

10.3390/en14133731 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3731

Author(s):

Simon Kamerling ◽

Valéry Vuillerme ◽

Sylvain Rodat

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Solar Thermal ◽

Outlet Temperature ◽

Field Mass ◽

Heat Demand ◽

Process Heat ◽

Solar Field ◽

Control Trajectory

Using solar power for industrial process heat is an increasing trend to fight against climate change thanks to renewable heat. Process heat demand and solar flux can both present intermittency issues in industrial systems, therefore solar systems with storage introduce a degree of freedom on which optimization, on a mathematical basis, can be performed. As the efficiency of solar thermal receivers varies as a function of temperature and solar flux, it seems natural to consider an optimization on the operating temperature of the solar field. In this paper, a Mixed Integer Linear Programming (MILP) algorithm is developed to optimize the operating temperature in a system consisting of a concentrated solar thermal field with storage, hybridized with a boiler. The MILP algorithm optimizes the control trajectory on a time horizon of 48 h in order to minimize boiler use. Objective function corresponds to the boiler use, for completion of the heat from the solar field, whereas the linear constraints are a simplified representation of the system. The solar field mass flow rate is the optimization variable which is directly linked to the outlet temperature of the solar field. The control trajectory consists of the solar field mass flow rate and outlet temperature, along with the auxiliary mass flow rate going directly to the boiler. The control trajectory is then injected in a 0D model of the plant which performs more detailed calculations. For the purpose of the study, a Linear Fresnel system is investigated, with generic heat demand curves and constant temperature demand. The value of the developed algorithm is compared with two other control approaches: one operating at the nominal solar field output temperature, and the other one operating at the actual demand mass flow rate. Finally, a case study and a sensitivity analysis are presented. The MILP’s control shows to be more performant, up to a relative increase of the annual solar fraction of 4% at 350 °C process temperature. Novelty of this work resides in the MILP optimization of temperature levels presenting high non-linearities, applied to a solar thermal system with storage for process heat applications.

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Simulation of Liquid-Gas Replacement in Commissioning Process for Large-Slope Crude Oil Pipeline

Volume 1: Upstream Pipelines; Project Management; Design and Construction; Environment; Facilities Integrity Management; Operations and Maintenance; Pipeline Automation and Measurement ◽

10.1115/ipc2012-90349 ◽

2012 ◽

Author(s):

Yuanyuan Chen ◽

Jing Gong ◽

Xiaoping Li ◽

Nan Zhang ◽

Shaojun He ◽

...

Keyword(s):

Crude Oil ◽

Flow Rate ◽

Liquid Flow ◽

Liquid Flow Rate ◽

Fluid Model ◽

Engineering Application ◽

Computational Procedure ◽

Control Measures ◽

Production Operation ◽

Oil Pipeline

Pipeline commissioning, which is a key link from engineering construction to production operation, is aim to fill an empty pipe by injecting water or oil to push air out of it. For a large-slope crude oil pipeline with great elevation differences, air is fairly easy to entrap at downward inclined parts. The entrapped air, which is also called air pocket, will cause considerable damage on pumps and pipes. The presence of it may also bring difficulties in tracking the location of the liquid head or the interface between oil and water. It is the accumulated air that needed to be exhausted in time during commissioning. This paper focuses on the simulation of liquid-gas replacement in commissioning process that only liquid flow rate exists while gas stays stagnant in the pipe and is demanded to be replaced by liquid. Few previous researches have been found yet in this area. Consequently, the flow in a V-section pipeline consisted of a downhill segment and a subsequent uphill one is used here for studying both the formation and exhaustion behaviors of the intake air. The existing two-fluid model and simplified non-pressure wave model for gas-liquid stratified flow are applied to performance the gas formation and accumulation. The exhausting process is deemed to be a period in which the elongated bubble (Taylor bubble) is fragmented into dispersed small bubbles. A mathematical model to account for gas entrainment into liquid slug is proposed, implemented and incorporated in a computational procedure. By taking into account the comprehensive effects of liquid flow rate, fluid properties, surface tension, and inclination angle, the characteristics of the air section such as the length, pressure and mass can be calculated accurately. The model was found to show satisfactory predictions when tested in a pipeline. The simulation studies can provide theoretical support and guidance for field engineering application, which are meanwhile capable of helping detect changes in parameters of gas section. Thus corresponding control measures can be adopted timely and appropriately in commissioning process.

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Experimental Investigation on Improvement of Wet Cooling Tower Efficiency with Diverse Packing Compaction Using ANN-PSO Algorithm

Energies ◽

10.3390/en14010167 ◽

2020 ◽

Vol 14 (1) ◽

pp. 167

Author(s):

Hasan Alimoradi ◽

Madjid Soltani ◽

Pooriya Shahali ◽

Farshad Moradi Kashkooli ◽

Razieh Larizadeh ◽

...

Keyword(s):

Neural Network ◽

Water Temperature ◽

Water Flow ◽

Flow Rate ◽

Cooling Tower ◽

Air Flow ◽

Water Flow Rate ◽

Pso Algorithm ◽

Outlet Temperature ◽

Air Flow Rate

In this study, a numerical and empirical scheme for increasing cooling tower performance is developed by combining the particle swarm optimization (PSO) algorithm with a neural network and considering the packing’s compaction as an effective factor for higher accuracies. An experimental setup is used to analyze the effects of packing compaction on the performance. The neural network is optimized by the PSO algorithm in order to predict the precise temperature difference, efficiency, and outlet temperature, which are functions of air flow rate, water flow rate, inlet water temperature, inlet air temperature, inlet air relative humidity, and packing compaction. The effects of water flow rate, air flow rate, inlet water temperature, and packing compaction on the performance are examined. A new empirical model for the cooling tower performance and efficiency is also developed. Finally, the optimized performance conditions of the cooling tower are obtained by the presented correlations. The results reveal that cooling tower efficiency is increased by increasing the air flow rate, water flow rate, and packing compaction.

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Study on Optimizing Operation of Preheating Commissioning for Waxy Crude Oil Pipelines

Advances in Mechanical Engineering ◽

10.1155/2014/894256 ◽

2014 ◽

Vol 6 ◽

pp. 894256

Author(s):

Jian Zhang ◽

Yi Wang ◽

Xinran Wang ◽

Handu Dong ◽

Jinping Huang ◽

...

Keyword(s):

Crude Oil ◽

Outlet Temperature ◽

Fluid Temperature ◽

Governing Equations ◽

Waxy Crude Oil ◽

Waxy Crude ◽

Oil Pipeline ◽

Single Station ◽

Oil Pipelines ◽

Volume Method

A mathematical model is established for the preheating commissioning process of waxy crude oil pipelines. The governing equations are solved by the finite volume method and the finite difference method. Accordingly, numerical computations are made for the Niger crude oil pipeline and the Daqing-Tieling 3rd pipeline. The computational results agree well with the field test data. On this basis, fluid temperature in the process of the preheating commissioning is studied for single station-to-station pipeline. By comparing different preheating modes, it is found that the effect of forward preheating is the best. Under different preheating commissioning conditions, the optimal combination of outlet temperature and flow rate is given.

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EXPERIMENTAL STUDY OF SOLAR AIR HEATER USING OF PHOTOVOLTAIC CELLS

International Journal of Engineering Technologies and Management Research ◽

10.29121/ijetmr.v4.i12.2017.139 ◽

2020 ◽

Vol 4 (12) ◽

pp. 103-106

Author(s):

Deeksha Vishwakarma ◽

Jyoti Kale

Keyword(s):

Experimental Study ◽

Forced Convection ◽

Flow Rate ◽

Storage System ◽

Flat Glass ◽

Photovoltaic Cells ◽

Solar Air Heater ◽

Outlet Temperature ◽

Air Flow Rate ◽

Air Heater

In this paper, we are studying about solar air heater. The solar air heater are consisting the several component such as flat glass, collector, D.C. fan, photovoltaic cells and electrical storage system. In this study we are achieving the various type of outlet temperature with the help of D.C. fan and various Mass air flow rate using of simple absorber trays forced convection.

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Receiver Outlet Temperature Control for Falling Particle Receiver Applications

ASME 2021 15th International Conference on Energy Sustainability ◽

10.1115/es2021-62319 ◽

2021 ◽

Author(s):

Nathan Schroeder ◽

Henk Laubscher ◽

Brantley Mills ◽

Clifford K. Ho

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Temperature Rise ◽

Pid Controller ◽

Input Parameter ◽

Slide Gate ◽

Process Variable ◽

Test Facility ◽

Outlet Temperature

Abstract Falling particle receivers (FPRs) are being studied in concentrating solar power applications to enable high temperatures for supercritical CO2 (sCO2) Brayton power cycles. The falling particles are introduced into the cavity receiver via a linear actuated slide gate and irradiated by concentrated sunlight. The thickness of the particle curtain associated with the slide-gate opening dimension dictates the mass flow rate of the particle curtain. A thicker, higher mass flow rate, particle curtain would typically be associated with a smaller temperature rise through the receiver, and a thinner, lower mass flow rate, particle curtain would result in a larger temperature rise. Using the receiver outlet temperature as the process variable and the linear actuated slide gate as the input parameter a proportional, integral, and derivative (PID) controller was implemented to control the temperature of the particles leaving the receiver. The PID parameters were tuned to respond in a quick and stable manner. The PID controlled slide gate was tested using the 1 MW receiver at the National Solar Thermal Test Facility (NSTTF). The receiver outlet temperature was ramped from ambient to 800°C then maintained at the setpoint temperature. After reaching a steady-state, perturbations of 15%–20% of the initial power were applied by removing heliostats to simulate passing clouds. The PID controller reacted to the change in the input power by adjusting the mass flow rate through the receiver to maintain a constant receiver outlet temperature. A goal of ±2σ ≤ 10°C in the outlet temperature for the 5 minutes following the perturbation was achieved.

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Unavoidable Destroyed Exergy in Crude Oil Pipelines due to Wax Precipitation

Entropy ◽

10.3390/e21010058 ◽

2019 ◽

Vol 21 (1) ◽

pp. 58

Author(s):

Qinglin Cheng ◽

JinWei Yang ◽

Anbo Zheng ◽

Lu Yang ◽

Yifan Gan ◽

...

Keyword(s):

Crude Oil ◽

Design Parameters ◽

Burial Depth ◽

Outlet Temperature ◽

Waxy Crude Oil ◽

Wax Precipitation ◽

Waxy Crude ◽

Oil Pipeline ◽

Oil Pipelines ◽

Operation Parameters

Based on the technological requirements related to waxy crude oil pipeline transportation, both unavoidable and avoidable destroyed exergy are defined. Considering the changing characteristics of flow pattern and flow regime over the course of the oil transportation process, a method of dividing station oil pipelines into transportation intervals is suggested according to characteristic temperatures, such as the wax precipitation point and abnormal point. The critical transition temperature and the specific heat capacity of waxy crude oil are calculated, and an unavoidable destroyed exergy formula is derived. Then, taking the Daqing oil pipeline as an example, unavoidable destroyed exergy in various transportation intervals are calculated during the actual processes. Furthermore, the influential rules under various design and operation parameters are further analyzed. The maximum and minimum unavoidable destroyed exergy are 381.128 kJ/s and 30.259 kJ/s. When the design parameters are simulated, and the maximum unavoidable destroyed exergy is 625 kJ/s at the diameter about 250 mm. With the increase of insulation layer thickness, the unavoidable destroyed exergy decreases continuously, and the minimum unavoidable destroyed exergy is 22 kJ/s at 30 mm. And the burial depth has little effect on the unavoidable destroyed exergy. When the operation parameters are simulated, the destroyed exergy increases, but it is less affected by the outlet pressure. The increase amplitude of unavoidable destroyed exergy will not exceed 2% after the throughput rises to 80 m3/h. When the outlet temperature increases until 65 °C, the loss increase range will not exceed 4%. Thus, this study provides a theoretical basis for the safe and economical transportation of waxy crude oil.

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