Heat Exchange Efficiency Research Articles

Waste heat recovery potential in the thermochemical copper–chlorine cycle for hydrogen production: Development of an efficient and cost-effective heat exchanger network

With the finite nature of fossil fuel resources and related environmental issues, it is necessary to replace fossil-fuel-based hydrogen production methods with more sustainable ones. For the clean production of hydrogen, the copper-chlorine (Cu–Cl) thermochemical cycle is a favorable choice. However, internal waste heat recovery of the cycle is essential to improve the efficacy of the system. In this paper, the waste heat recovery potential of the four-step Cu–Cl cycle is investigated, to support the design of a new cost-effective and high-performance heat exchanger network. Pinch analysis is executed to find the optimum rates of cold and hot utilities for this cycle. Three heat exchanger network cases are investigated which include case 1, without heat recovery; case 2, with 16 heat exchangers; and case 3, with 11 heat exchangers. The effect of varying design parameters on the energy system's efficiency and cost-related parameters are also explored here. Based on the pinch analysis results, the minimum heating and cooling and the maximum recoverable heat, on a normalized basis, are 333.3 kJ/mol H2, 76.9 kJ/mol H2, and 134.4 kJ/mol H2, respectively. Moreover, for cases 1, 2, and 3 the thermal efficiencies are calculated as 33.3%, 41.1%, and 40.5%, respectively. Additionally, it is observed that, when the thermal energy of the cycle is supplied from a solar power tower plant, the levelized cost of hydrogen for case 1 is 9.6 $/kg H2, for case 2 is 7.9 $/kg H2, and for case 3 is 7.8 $/kg H2.

Study on heat-exchange efficiency and energy efficiency ratio of a deeply buried pipe energy pile group considering seepage and circulating-medium flow rate

Seepage and circulating-medium flow rate are both primary factors affecting the heat-exchange efficiency and energy efficiency ratio of underground energy structures. In this study, a thermal-seepage coupled model of a deeply buried pipe energy pile group is developed, and the effects of circulating-medium flow rate, seepage velocity, and thermal migration caused by seepage on heat-exchange efficiency and energy efficiency ratio are analyzed. The results show that increasing the circulating-medium flow rate can improve heat-exchange efficiency, but aggravate heat accumulation, resulting in energy efficiency ratio reduction. Seepage can eliminate the heat accumulation as well as improve the heat-exchange efficiency and energy efficiency ratio. The heat accumulated around upstream piles will migrate along the seepage direction, generating thermal disturbance to the downstream piles. An increase in the circulating-medium flow rate of upstream deeply buried pipe energy piles will aggravate thermal disturbance. This phenomenon is slightly retarded if seepage velocity is increased. Additionally, when the circulating-medium flow rate of the deeply buried pipe energy pile group under seepage is within the optimal range, slightly reducing the circulating-medium flow rate of the upstream deeply buried pipe energy piles can reduce thermal disturbance to the downstream piles without affecting the overall heat-exchange efficiency.

Study on the Effective Well Depth of Single U-Shaped Vertical Buried Pipes Based on Temperature Difference Analysis.

A heat transfer model of a single U-shaped vertical buried pipe similar to an actual scenario is established, and the accuracy of the model is verified by experiments. The model is used to analyze the heat transfer performance of vertical buried pipe heat exchangers with well depths of 200, 160, 120, and 80 m. This includes the heat transfer per unit well depth, temperature change of the well wall and fluid along the pipe length, heat transfer coefficient, and section heat transfer validity. With the increase in well depth, the heat exchange per unit well depth decreases, and the proportion of heat exchange in the inlet section to the total heat exchange increases. When the well depths are 200, 160, 120, and 80 m, the last 10 m pipe sections have 30, 40.3, 53.7, and 66.4% of the heat exchange efficiencies of the initial 10 m pipe section, respectively. To obtain a reasonably effective well depth of a single U-shaped vertical buried pipe, it is necessary to comprehensively consider the heat exchange per unit well depth, the temperature difference between the well wall and the fluid, and the energy efficiency of the buried pipe section. Moreover, it should be analyzed in combination with economic factors.

Study on the intrinsic mechanisms underlying enhanced geothermal system (EGS) heat transfer performance differences in multi-wells

The effectiveness of the multi-well arrangement mode in enhanced geothermal systems in large-scale fields has been well established. However, the mechanisms that lead to variations in heat transfer performance between different numbers of well arrangements have remained unclear. In this study, the multi-well pattern was segmented into several double-well units and a mathematical model was constructed to investigate seepage heat transfer in enhanced geothermal systems using numerical simulation techniques. The lifespan and heat transfer characteristics of both multi-well and corresponding double-well units were examined, with supplementary experimental validation. Additionally, a flow reduction coefficient for multi-well systems was proposed to explain the differences in heat transfer performance caused by the pressure superposition of multiple-well seepage fields. It was found that heat extraction from a multi-well enhanced geothermal system is equivalent to the linear superposition of corresponding double-well units. Furthermore, the lifespan of multi-well systems is significantly longer than that of corresponding double-well systems due to the influence of the multi-well flow reduction coefficient. In fact, this difference can exceed threefold in nine-well arrangements, resulting in reduced efficiency of multi-well heat exchange. This work provides a novel perspective on exploring the intrinsic mechanisms that underlie differences in heat transfer performance in enhanced geothermal systems from a flow field perspective. It contributes to a better understanding of optimal well arrangement modes for enhanced geothermal systems and supports the development of large-scale geothermal fields.

Polymeric hollow fiber heat transfer surface for heat exchanger

Polymeric heat transfer surfaces (HTS) offer numerous advantages, such as flexibility, fouling resistance, corrosion and chemical resistance, and good recyclability. Moreover, polymeric materials have a lower carbon footprint than commonly used metal materials in the heat exchanger industry, making them an environmentally-friendly choice. In this study, we propose a novel nonwoven fabric technology for the fabrication of HTS. This technology enables the production of three-dimensional objects with precisely separated hollow polymeric fibers, resulting in highly efficient polymeric heat exchangers (HE). The fabrication process is based on the hot melt technique, where the polymeric melt (helmitin 42048) is perpendicularly applied to the longitudinal hollow fibers (polyamide 612). To evaluate the performance of the developed HTS, polymeric HE was produced and compared with a conventional aluminum HE, which served as a heater core in a gas-to-liquid application. The polymeric HE exhibited similar pressure losses on the liquid side and slightly higher losses on the gas side while achieving comparable thermal performance. For a liquid flow rate of 150 l·h−1 and an air velocity of 4 m·s−1, the polymeric HE reached a maximum thermal performance of almost 0.8 kW. The results demonstrate the functionality of the developed HTS technology and its potential as an advancement in heat transfer processes. The utilization of polymeric HTS in heat exchangers shows promising prospects for enhanced thermal performance, paving the way for sustainable and efficient heat transfer applications.

Assessment of micro-scale heat exchangers efficiency using lattice Boltzmann method and design of experiments

The study is focused on the use of nanofluids in a micro-open tall cavity, which is a type of micro heat exchanger (MHE). The cavity is heated from the bottom sidewall in a sinusoidal pattern, and the effects of four input parameters (Ra, Ha, Kn, and Vf) on heat transfer and irreversibility are investigated using numerical simulations based on Lattice Boltzmann Method (LBM). The findings of the study suggest that the local heat transfer on the bottom sidewall is strongly influenced by Ra and Ha, while the surface distribution of entropy generation is mainly dependent on Kn. The study also shows that the optimization of the magnitude and wavelength of the sinusoidal temperature can improve both local heat transfer and surface distribution of entropy generation. The results of the study provide valuable insights into the design of micro heat exchangers and suggest that the optimization of micro-porous geometries using DOE could lead to increased energy efficiency. The study contributes to our understanding of the complex interactions between input parameters in micro heat exchangers and highlights the importance of considering multiple parameters in the design process.

Numerical study of the dehydration and hydration processes of the Ca(OH)2/CaO system in an indirect-direct reactor

Energy storage is important for the application of the discontinuous and unstable renewable energy. The CaO/Ca(OH)2 thermochemical system of high energy density and little heat lose is promising for thermal energy storage, yet the heat and mass transfer processes related to dehydration reaction needs further improvement and the regulation manner related to the hydration reaction needs further investigation. In this work, a hybrid indirect-direct reactor of the CaO/Ca(OH)2 system is proposed with the physicochemical model developed to study the dehydration and hydration processes under different operating and structural conditions, and five indicators are defined to evaluate the overall reaction performance. During the dehydration process, the reactant is indirectly heated by the electrical heater at the reactor outside wall and the reaction proceeds in radial direction which is mainly limited by the poor heat transfer, leading to low energy storage efficiency of 6.1 %. The increase of reactant thermal conductivity and application of high-thermal-conductivity porous channel greatly enhance the heat transfer leading to significant reduction of reaction time and increase of energy storage efficiency up to 25.63 %. During the hydration process, the gas mixture directly contacts and reacts with solid reactant and the reaction proceeds in axial direction with reaction region of “U” shape which is mainly restricted by the reaction equilibrium. The thermal power density and reaction temperature of the hydration process can be regulated by the inlet mass flow rate and the inlet steam mass fraction respectively. The increase of inlet mass flow rate and inlet steam mass fraction leads to higher heat exchange efficiency at the same reaction extent and shorter hydration reaction time. The present study demonstrates the superiority of the indirect-direct type reactor and the performance of which can be further improved by optimizing the geometrical and operating conditions.

Increasing Thermal Efficiency: Methods, Case Studies, and Integration of Heat Exchangers with Renewable Energy Sources and Heat Pumps for Desalination

The article presents an overview of modern analytical methods and experimental studies on the use of heat exchangers as part of different schemes, as well as technologies that increase the efficiency of heat exchangers using renewable energy sources. The main types of heat exchangers, and the principles of their operation, are considered. In addition, modern technologies for increasing the efficiency of heat exchangers through design are described. The practical experience of using plate heat exchangers in industry has been studied. An overview of the software development that is used in the design and optimization of heat exchange devices, as well as for the improvement of their energy efficiency, is presented. The presented mathematical models can be used for software that is applicable both to individual segments of plates of heat exchangers and heat exchangers in general, taking into account the dependence of the installation of the entire circuit on environmental parameters and location. In conclusion, recommendations are given for further research directions in the field of using heat exchangers with the inclusion of renewable energy sources. The technique of an energy technology complex, including a heat pump, a photovoltaic panel, and a desalination plant, is presented. The methodology is built around the basic design and energy balance of the complex, and it is also considered from the point of view of the exergetic balance. This allows for the use of additional components, such as a turbo expander for the implementation of the organic Rankine cycle, a wind turbine, and a solar concentrator. This scientific approach can become unified for the design and operation of an energy technology complex. In addition, an exergetic calculation method is presented for a thermal desalination plant operating as part of an energy technology complex with renewable energy sources.

Geographic and transport controls of temperature response in karst springs

Thermal responses of groundwater are useful signatures to reveal the recharge-discharge process and characterize aquifer structure in karst groundwater. Four karst springs with varying circulation depths ranging from ∼ 60 to 820 m in South China, were used to decipher the mechanism of heat exchange between recharge water and surrounding rock formations. An analytical solution of heat transfer in karst conduit was proposed to simulate the peak or trough temperatures of pulse flow. Hydraulic diameter, flow velocity, input temperature and circulation depth in karst aquifer, mainly depending on the recharge water volume after rainfall events, are important transport factors to control the thermal equilibrium depth and the efficiency of heat exchange that directly controls the behavior of warm peaks or cold troughs in groundwater temperature. In shallow karst aquifers wherein the circulation depth is less than its theoretical thermal equilibrium depth, the recharge water does not sufficiently exchange heat with the surrounding rocks, resulting in clear event-scale warm peaks in summer and cold troughs in winter. Otherwise, the recharge water will firstly reach a thermal equilibrium state and then mix with the warmer base flow at deeper location, which is verified in a karst spring with anomalous event-scale temperature drops after rainfall events all year around. The thermal response simulations obtained from this work provide new ways and insights to characterize geographic structure of karst aquifer and elucidate heat transfer mechanism in karst aquifer systems.

An earth-air heat exchanger integrated with a greenhouse in cold-winter and hot-summer regions of northern China: Modeling and experimental analysis

This study aimed to investigate the thermal performance of Earth-Air Heat Exchangers (EAHE) in greenhouses in northern China's cold winter and hot summer regions. The experiment was conducted in two identical greenhouses (with and without an EAHE), and a mathematical and Computational Fluid Dynamics (CFD) simulation model was established to predict the air temperature inside the greenhouse and heat exchanger outlets and verified with measured data. Parametric analysis was also performed, and the effect of long-period application was evaluated. The results showed that the data calculated by the model agreed well with the experimental data. The average differences between the inlet and outlet air temperatures of the EAHE, daily average heat exchange capacity, and coefficient of performance (COP) was 9.26 ℃, 18.86 MJ, and 22.49 in winter, respectively, while in summer, they were 10.55 ℃, 18.78 MJ, and 23.52, respectively. The night-time temperature of the greenhouse increased by 1.43 °C during winter, while the temperature during summer daytime was reduced by 2.10 ℃. An increase in the pipe length improves the heat exchange efficiency, the heat exchange mainly occurs in the first half of the horizontal pipe, and the increase in air velocity and operation time will reduce the heat exchange efficiency. In conclusion, the system was proposed as a viable auxiliary device for greenhouse heating and cooling in cold winter and hot summer regions and to reduce greenhouse gas emissions. The system is recommended to be arranged outdoors for cooling and indoors for heating.

Effect of annular ribs in heat exchanger tubes on the performance of phase‐change regenerative heat exchangers

AbstractOptimizing the efficiency of conventional heat exchangers is critical for improving the performance of various processes. This study proposed increasing the heat dissipation buffer space of heat exchangers by filling the gap between the heat exchanger and the shell with phase‐change materials for optimizing phase‐change heat exchangers. Comparative simulation analyses were performed by investigating the difference between the internal and external diameters of the inner ring ribs of the heat exchanger, the flow rate of the cooling liquid, the spacing distance, and the number of the inner ring ribs as independent variables. The results revealed that the heat transfer efficiency of heat exchangers can be improved by adding the inner ring rib structure to the heat exchange copper tube. The difference between the inner and outer diameters of the inner ring rib considerably influences heat dissipation. Furthermore, a sensitivity coefficient of 0.2457 can be obtained. The distance and number of inner ring ribs and the flow rate of cooling liquid exhibit certain effects on the heat transfer efficiency of the heat exchanger. The sensitivity coefficients were 0.1477 and 0.0935. The heat dissipation efficiency of the coil heat exchanger was improved by 3.8% by adding inner ring ribs in the coil heat exchanger channel.

Coupled THM formulation and wellbore analytical solution in naturally fractured media during injection/production

The heat extraction efficiency, storage, and safety of carbon dioxide (CO2) sequestration and methane (CH4) injection/post-production in naturally fractured formations have attracted significant interest. However, these studies require the examination of complex thermal-hydraulic-mechanical (THM) interacting processes, which include muti-discipline coupling and phase changes. Energy transfer mechanisms and thermally induced hydraulic and mechanical responses are critical for energy extraction efficiency , surface design optimization, and safety evaluation. The THM response in the wellbore, where fluids are injected and circulated, provides key information for design evaluation. A fully coupled formulation was developed based on a dual-porosity model to simulate the THM responses of a wellbore in naturally fractured aquifers under non-isothermal, two-phase fluid flow, and non-hydrostatic loading conditions. Local thermal non-equilibrium (LTNE) conditions are imposed for energy transportation between the fracture and matrix systems in the fissured porous solid skeleton. Different physical parameters reflecting various rock types and fracture characteristics are defined for the corresponding THM behavior models. Analytical solutions for the temperature perturbation and pressure changes in single-phase fluid flow in the vicinity of a wellbore in fissured media are developed to simulate the injection and production processes. Simulating a non-isothermal fluid circulation problem along a wellbore, an newly proposed mixed Type I (Dirichlet) and II (Neumann) boundary condition is imposed to study the heat exchange efficiency between wellbore fluid and the fissured NFM. The analytical solution has the advantages of being simple, explicitly possessing direct physical parameters, and serving as a tool for validating numerical solutions. The impacts of the newly proposed boundary condition on the near-well responses and THM results from the newly developed solution may be used to simulate the injectivity, storage capacity, reproduction, and design of supercritical carbon (scCO2) and CH4 are discussed.

Case study of thermal and solutal aspects on non-Newtonian Prandtl hybrid nanofluid flowing via stretchable sheet: Multiple slip solution

The effect of multiple slip boundary conditions is one more important physical parameter on the flow investigation and have been studied in this analysis. Further, the effect of Ohmic heating and varying chemical reaction on non-Newtonian Prandtl hybrid nanofluid with water based nanofluids to an extending of leading edge was also investigated to this current analysis. An inclined magnetic field is introduced to fluid flow to regulate the fluid stream. Hybrid nanomaterial is synthesized by the dispersion of Cu and Cofe2O4 nanoparticles in Prandtl fluid. All chemical science specifications of nanofluid are measured as constant. Due to the nanofluid particles motion, the fluid concentration is inspected underneath chemical implications. A mathematical model is developed by assuming the flow as incompressible and purely cartesian coordinate system and appropriate non-dimensional variables are introduced for problem simplifications and dimensional analysis. The scheme for semi analytical study named Homotopy Analysis Method (HAM) is implied to get solutions to the equations. The procedure is then displayed pictorially where fluid velocity, temperature and concertation against various pertinent parameters are examined. It was found that, the Concentration field profiles have been shown to deteriorate because molecule diffusivity reduces as the chemical reaction parameter rises in both cases. In order to maintain thermal balance management in tiny heat density equipment and gadgets, current research may also be helpful in enhancing the thermal efficiency of heat exchangers.

Soret and Dufour effects on MHD mixed convection flow of Casson hybrid nanofluid over a permeable stretching sheet

The use of hybrid nanofluids can improve the engine operation and fuel efficiency in automotive engineering, as well as the efficiency of cooling systems used in food processing and preservation. This study provides insight for the development of efficient heat exchangers, thermal energy storage systems and cooling systems for various industrial applications, which can improve product quality and safety. The study aims to investigate the Soret and Dufour effects in hybrid nanofluid flow, with the goal of understanding their behaviour and potential applications in various industries. The flow is over a vertically stretched permeable sheet with porous material under convective boundary conditions and a non-uniform heat source/sink. The reduced governing equations are represented by non-linear-coupled ordinary differential equations solved by means of the shooting method based on the fourth-order Runge–Kutta method. Enhancing the Casson parameter reduces the fluid velocity while enhancing the mass and thermal Grashof numbers increases the flow velocity. The Soret and Dufour effects improve temperature and concentration, and a higher Biot number increases the temperature. The novelty of this investigation lies in its incorporation of Soret and Dufour effects, porosity, heat source/sink and a more refined definition of nanoflow, which is compared to previous results.

Design and Analysis of Heat Pipe Heat Exchanger Efficiency

The heat pipe has a high thermal conductivity, and its basic working principle is to transfer heat through evaporation and condensation through the working medium inside the pipe. Heat pipe has good thermal conductivity, isotherm and other characteristics, and the heat transfer area at both ends can be changed at will, control the temperature and other advantages. Therefore, the heat pipe heat exchanger has the advantages of high heat transfer efficiency, compact structure, small fluid resistance loss, and beneficial to control dew point corrosion. At present, it has been widely used in metallurgy, chemical industry, oil refining, boiler, ceramics, transportation, light textile, machinery and other industries, as energy saving equipment for waste heat recovery and heat energy utilization in the process, and has achieved remarkable economic benefits. The design of the heat pipe heat exchanger on the development of the current situation, development trend, application, design principle and design process of a simple description, while focusing on the discussion of the heat pipe heat exchanger design process. The main content of the heat exchanger thermodynamic calculation, structural design and material selection. The model of heat pipe heat exchanger is established according to the actual situation and the calculated data.

Experimental Study on the Thermal Performance of Flat Loop Heat Pipe Applied in Data Center Cooling

The cooling system is the auxiliary equipment that consumes the most energy in a data center, accounting for about 30 to 50% of the total energy consumption. In order to effectively reduce the energy consumption of a data center, it is very important to improve the heat exchange efficiency at the chip level. Compared with air cooling, single-phase cold plate liquid cooling, and immersion liquid cooling, the flat loop heat pipe (FLHP) is considered to be a better chip-level cooling solution for data centers. It has extremely high heat transfer efficiency and heat flux variability, and it can avoid the operation risk caused by liquid entering the server. In this paper, a FLHP with an evaporator designed with a “Tesla valve” flow channel configuration is developed. Experiments on the FLHP are carried out, focusing on the installation angles and cooling condition factors. The results show that an inclination angle of 20° is the critical point of the influence of gravity on the performance of the FLHP; to ensure good operation of the FLHP, the installation angle should be greater than 20°. The equivalent heat transfer coefficients of the FLHP condenser under different cooling conditions are calculated. It is found that water cooling can provide higher cooling heat transfer coefficients with lower energy consumption and operating noise. Additionally, the heat transfer limit, operating temperature uniformity, and start-up stability of the FLHP are significantly improved under water cooling conditions. The maximum heat load of the FLHP is up to 230 W, and the temperature difference of the evaporator surface can be controlled within 0.5 °C, under 20 °C water cooling. Finally, using the FLHP for thermal management of the chip, its heat transfer efficiency is 166 and 41% higher than that of air cooling and water cooling, respectively.

The efficacy of magnetic force on thermal performance of ferrofluid in a screw tube

The applications of ferro nanoparticles have been widely increased in heat exchangers due to their significant thermal properties. In current research, the computational technique is established to scrutinize the impact of the non-uniform Kelvin force. This research discloses the impact of the variable MHD in hydrothermal characteristics of a screw heat exchanger with the nanofluid stream. For this purpose, a parallel wire is selected as a source of the magnetic field. In this model, water with 4 vol% nanoparticles is applied to achieve nanofluid. To simulate the nanofluid inside this type of exchangers, the finite volume technique is chosen for managing and coupling of the pressure–velocity. Obtained results show good agreement with experimental data. Different factors are implemented to expose the role of the geometrical parameter, Re and variable magnetic field on the thermal efficiency of the screw heat exchanger. Archived results show that the impact of the Re on the nanofluid flow is more than the screw diameter. Our findings show that skin friction of nanofluid due to the rising of screw diameter is considerably more than Reynolds number.

Process Parameters Analysis of Ethylene Glycol-Water and Air-Glycol System in Shell and Tube Heat Exchanger

Process parameter analysis plays a vital role in today's modern world in all industries. The demand for energy consumption in industries has made designers build efficient heat exchangers. One of the most used heat exchangers is the shell and tube heat exchanger. This work is based on analyzing velocity profile, temperature, and pressure in shell and tube heat exchangers. Thermal analysis and flow analysis is considered as basic method to be performed along with some basic structural analysis by means of individual analysis of heat transfer components. The simulation also provides insights into the flow behavior and temperature distribution in the heat exchanger, which can be used for optimizing the design and operation of the device. Results based on those analyses are collected and experimented to get the required output values. In this study, we utilize COMSOL Multiphysics, a powerful computational tool for simulating heat transfer phenomena, to model and analyze the performance of a shell and tube heat exchanger. In this process, we use water - ethylene glycol system and an air- glycol system as a component in the shell and tube side. Across industries and disciplines, simulation modeling provides valuable solutions by giving clear insights into complex systems. The main objective of this study is to investigate the thermal performance of the heat exchanger by simulating the fluid flow and heat transfer processes inside the tubes and the shell. Keywords: shell and tube heat exchanger, analysis, thermal performance, comsol software.

Polyethylene/poly (N, N-dimethyl acrylamide) hybrid hydrogel membrane for total heat exchanger

For the total heat exchange membrane, there is a compromise effect between the moisture permeability and the gas barrier. To overcome this challenge, a new type of total heat exchange membrane was proposed involving a porous polyethylene (PE) membrane and a hydrophilic poly (N, N-dimethyl acrylamide) (PDMAA) hydrogel. A dense PE/PDMAA composite membrane was fabricated via an in situ photoinitiated free-radical polymerization and cross-linking reaction through a pre-permeation of N, N-dimethyl acrylamide (DMAA) monomers in the porous structure of the PE membrane. In this study, we systematically investigated the effect of varying amounts of PDMAA filler on membrane morphology, hydrophilicity, stability, mechanical properties, water vapor transmission rate, gas barrier property, and total heat exchange efficiency. These results demonstrate that a tight, stable PE/PDMAA hybrid membrane with an interlocked structure has been created. Water vapor diffusion channels and an efficient carbon dioxide (CO2) barrier were successfully constructed through the introduction of a cross-linked PDMAA hydrogel. Improvements in water vapor transmission rate and reduction in CO2 transmission rate were achieved simultaneously with increasing PDMAA filling amount. Excellent mechanical properties and hybrid stability were also observed for the composite membrane obtained. This work provides a novel total heat exchange membrane with convenient production process, low cost and high durability characteristics.

Numerical Analysis of the Deposition Characteristics in the Initial Deposition Stage in RSC

The coal gasification syngas cooler is important for recovering the sensible heat generated during coal gasification. The ash layer formed on the heat transfer surface can seriously decrease the heat exchange efficiency. Establishing the initial layer is a prerequisite for massive ash deposition and will accelerate the accumulation of the ash and slag particles. In this study, numerical simulations are conducted to analyze the behavior of ash particles in large-scale industrial equipment. The deposition characteristics during the initial fouling and slagging stage in RSC are explored. The results show that in this stage, ash or slag particles mainly stick on the side wall, and only small particles deposit on the upper cone. The surface energy is the dominant factor influencing the composition of the initial layer. The adhesion ratio of FeS2 and ZnS particles is over ten times higher than that of SiO2 particles. With the decrease of the inlet flow rate and the increase of the inlet swirl velocity, the location corresponding to the maximum deposition proportion moves upward, and the local maximum deposition proportion increases.