scholarly journals Study of fouling in graphite blocks (cross flow) heat exchanger of phosphoric acid concentration process

2020 ◽  
Vol 330 ◽  
pp. 01038
Author(s):  
Rania Jradi ◽  
Christophe Marvillet ◽  
Mohamed Razak Jeday
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Phosphoric Acid ◽  
Transfer Coefficient ◽  
Acid Concentration ◽  
Fouling Resistance ◽  
Concentration Process ◽  
Overall Heat Transfer Coefficient ◽  
Phosphoric Acid Concentration

Fouling in phosphoric acid concentration process of preheat exchangers is a chronic operational problem that compromises energy recovery in these systems. Progress is hindered by the lack of quantitative knowledge of the dynamic effects of fouling on heat exchanger transfer. The subject of this work is an experimental determination of the thermal fouling resistance in the graphite blocks heat exchanger installed in a phosphoric acid concentration process. By measuring the inlet and outlet temperatures and mass flows of fluids, the overall heat transfer coefficient has been determined. Determining the overall heat transfer coefficient for the heat exchanger with clean and fouled surfaces, the fouling resistance was calculated. The results obtained from the heat exchanger studied, show that the fouling resistance increase with time presenting an exponential evolution in agreement with the model suggested by Kern and Seaton, with the existence of fluctuation caused by the instability of the flow rate and the temperature. Bad cleaning of the heat exchanger involves the absence of the induction period and consequently, causes high values of the fouling resistance and of the deposit fouling during a relatively short period of time.

scholarly journals Tubular Heat Exchanger Fouling in Phosphoric Acid Concentration Process

2020 ◽  
Author(s):  
Rania Jradi ◽  
Ali Fguiri ◽  
Christophe Marvillet ◽  
Mohamed Razak Jeday
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Phosphoric Acid ◽  
Acid Concentration ◽  
Fouling Resistance ◽  
Tubular Heat Exchanger ◽  
Concentration Process ◽  
Phosphoric Acid Concentration

Fouling in phosphoric acid concentration is a persistent operational problem that compromises energy recovery in this process. Progress is hampered by the lack of quantitative knowledge of fouling dynamic effects on heat exchanger transfer. The object of this work is an experimental determination of the thermal fouling resistance in the tubular heat exchanger of phosphoric acid preheated installed in phosphoric acid concentration process. By measuring the inlet and outlet temperatures of phosphoric acid, steam temperature, suction and discharge pressure of the pump and acid density measurement, the overall heat transfer coefficient has been determined. The determination of the overall heat transfer coefficient with clean and fouled surfaces, allowed calculating the fouling resistance. The results from the heat exchanger studies showed that the fouling resistance increased with time and presented an asymptotic evolution in compliant with the proposed model by Kern and Seaton, with the existence of fluctuation. The poorly cleaned heat exchanger implied the absence of the induction period and caused, consequently, high values of the fouling resistance in a relatively short-time period.

scholarly journals Design of Flue Gas-Air Heat Exchanger for Regeneration of Desiccant System

2018 ◽  
Vol 225 ◽  
pp. 05006 ◽  
Author(s):  
Shaymaa H. Abdulmalek ◽  
Hussain H. Al-Kayiem ◽  
Aklilu T. Baheta ◽  
Ali A. Gitan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Waste Heat ◽  
Thermal Characteristics ◽  
Tube Diameter ◽  
Fuel Gas ◽  
Overall Heat Transfer Coefficient ◽  
Heat Exchanger Design

Heat recovering from biogas waste energy requires robust heat exchanger design. This paper presents the design of fuel gas-air heat exchanger (FGAHE) for recovering waste heat from biogas burning to regenerate desiccant material. Mathematical model was built to design the FGAHE based on logarithmic mean temperature difference (LMTD) and staggered tube bank heat transfer correlations. MATLAB code was developed to solve the algorithm based on overall heat transfer coefficient iteration technique. The effect on tube diameter on design and thermal characteristics of FGAHE is investigated. The results revealed that the smaller tube diameter leads to smaller heat transfer area and tube. On the other hand, the overall heat transfer coefficient and Nusselt numbers have larger rates at smaller tube diameter. In conclusion, the nominated tube diameter for FGAHE is the smaller diameter of 0.0127 m due to the high thermal performance.

scholarly journals Experimental Investigation Of Heat Transfer Characteristics Of Nanofluid Using Parallel Flow, Counter Flow And Shell And Tube Heat Exchanger

2015 ◽  
Vol 62 (4) ◽  
pp. 509-522 ◽  
Author(s):  
R. Dharmalingam ◽  
K.K. Sivagnanaprabhu ◽  
J. Yogaraja ◽  
S. Gunasekaran ◽  
R. Mohan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube

Abstract Cooling is indispensable for maintaining the desired performance and reliability over a very huge variety of products like electronic devices, computer, automobiles, high power laser system etc. Apart from the heat load amplification and heat fluxes caused by many industrial products, cooling is one of the major technical challenges encountered by the industries like manufacturing sectors, transportation, microelectronics, etc. Normally water, ethylene glycol and oil are being used as the fluid to carry away the heat in these devices. The development of nanofluid generally shows a better heat transfer characteristics than the water. This research work summarizes the experimental study of the forced convective heat transfer and flow characteristics of a nanofluid consisting of water and 1% Al2O3 (volume concentration) nanoparticle flowing in a parallel flow, counter flow and shell and tube heat exchanger under laminar flow conditions. The Al2O3 nanoparticles of about 50 nm diameter are used in this work. Three different mass flow rates have been selected and the experiments have been conducted and their results are reported. This result portrays that the overall heat transfer coefficient and dimensionless Nusselt number of nanofluid is slightly higher than that of the base liquid at same mass flow rate at same inlet temperature. From the experimental result it is clear that the overall heat transfer coefficient of the nanofluid increases with an increase in the mass flow rate. It shows that whenever mass flow rate increases, the overall heat transfer coefficient along with Nusselt number eventually increases irrespective of flow direction. It was also found that during the increase in mass flow rate LMTD value ultimately decreases irrespective of flow direction. However, shell and tube heat exchanger provides better heat transfer characteristics than parallel and counter flow heat exchanger due to multi pass flow of nanofluid. The overall heat transfer coefficient, Nusselt number and logarithmic mean temperature difference of the water and Al2O3 /water nanofluid are also studied and the results are plotted graphically.

Heat Transfer and Pressure Drop Analysis of Chilled Water and Ice Slurry in a Plate Heat Exchanger

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Rajinder Singh ◽  
Surendra Singh Kachhwaha
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Ice Slurry ◽  
Plate Heat ◽  
Overall Heat Transfer Coefficient ◽  
Chilled Water

The present study reports the experimental validation of thermohydraulic modeling for prediction of pressure drop and heat transfer coefficient. Experiments were performed on plate heat exchanger using chilled water and ice slurry as secondary fluids. Propylene glycol (PG) and mono-ethylene glycol (MEG) are used as depressants (10%, 20%, 30%, and 40% concentration) in ice slurry formation. The results show that thermohydraulic modeling predicts the pressure drop and overall heat transfer coefficient for water to water and water to ice slurry within the discrepancy limit of ±15%.

scholarly journals Optimization of Earth Air Tube Heat Exchanger for Cooling Application Using Taguchi Technique

2020 ◽  
Vol 38 (4) ◽  
pp. 845-862
Author(s):  
Saif Nawaz Ahmad ◽  
Om Prakash
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Pipe Material ◽  
Ground Heat Exchanger ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
The Earth ◽  
Inner Diameter

Earth air tube heat exchanger (EATHE) is one of the passive technologies which utilize the earth stored heat (renewable energy) for heating/cooling the buildings. EATHE releases heat to earth for cooling space in summer, making the earth a heat sink and extracts earth-stored energy for heating space in winter and makes the earth a heat source. This paper optimizes the Length of the ground heat exchanger and overall heat transfer coefficient of earth air heat exchanger using the Taguchi technique for cooling application. For this purpose, we select six factors such as installation depth of Pipe (A), Pipe's inner diameter (B), Thermal conductivity of pipe material (C), Inlet air temperature (D), Outlet air temperature (E), Inlet air velocity (F). All these factors are taken at three levels, and we select an L27 orthogonal array for experimental runs. The ground heat exchanger's Length and the overall heat transfer coefficient were then calculated for each experimental run. In the Taguchi method, we find the signal to noise ratio for an optimal combination of all six factors and ANOVA to find the order of influencing parameters and their percentage contributions for both the objective parameters. According to our results, the best combination for all the six factors for ground heat exchanger length and overall heat transfer coefficient were A1B1C3D1E3F1 and A2B3C2D3E1F3, respectively. The highest and lowest influencing factors for ground heat exchanger length were the pipe's inner diameter and the pipe's installation depth with their contribution factors of 69.12 and 0.32%, respectively. In contrast, the highest and lowest influencing factors for the overall heat transfer coefficient were the pipe's inner diameter and thermal conductivity of pipe material with their contribution factors of 75.97and 0%, respectively. Hence the order of influence of all the six factors for both the objective parameters was BEFDCA.

scholarly journals Performance Analysis of Shell and Tube Type Heat Exchanger Using Aluminium Oxide (Al2O3) Nano-Particle

2021 ◽  
Vol 9 (9) ◽  
pp. 157-164
Author(s):  
Paritosh Singh
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Solid Particles ◽  
Tube Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube ◽  
Evacuated Tube

Abstract: Research in convective heat transfer using suspensions of nanometer sized solid particles in a base fluid started only over the past decade. Recent investigations on nanofluids, as such suspensions are often called, indicate that the suspended nanoparticles markedly change the transport properties and heat transfer characteristics of the suspension. The very first part of the research work summarizes about the various thermo physical properties of Al2O3 Nanofluid. In evacuated tube solar water heating system nanofluids are used as primary fluid and DM water as secondary fluid in Shell and Tube Heat Exchanger. The experimental analysis of Shell and Tube heat exchanger integrated with Evacuated tube solar collector have been carried out with two types of primary fluids. Research study of shell and tube heat exchanger is focused on heat transfer enhancement by usage of nano fluids. Conventional heat transfer fluids have inherently low thermal conductivity that greatly limits the heat exchange efficiency. The result of analysis shows that average relative variation in LMTD and overall heat transfer coefficient is 24.56% and 52.0% respectively. The payback period of system is reduced by 0.4 years due to saving is in replacement cost of Evacuated Tube Collector. Keywords: ETC; Nanofluid; LMTD; Thermal Conductivity; Overall heat transfer coefficient

Heat exchanger network retrofit throughout overall heat transfer coefficient by using genetic algorithm

2016 ◽  
Vol 94 ◽  
pp. 274-281 ◽  
Author(s):  
Totok Ruki Biyanto ◽  
Enrico Kevin Gonawan ◽  
Gunawan Nugroho ◽  
Ridho Hantoro ◽  
Hendra Cordova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Genetic Algorithm ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Exchanger Network ◽  
Overall Heat Transfer Coefficient
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