scholarly journals Heat and mass transfer droplets of n-Hexane and n-Heptane towards temperature and rate of air flow rate variations

2019 ◽  
Author(s):  
Engkos Achmad Kosasih ◽  
Dwiki Prasetyo ◽  
Amudi Tua Siahaan ◽  
Ardiyansyah Yatim ◽  
Agus Sunjarianto Pamitran
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Flow Rate ◽  
Air Flow ◽  
Air Flow Rate

scholarly journals Pengaruh Laju Aliran Udara Terhadap Efisiensi Penyisihan Organik di dalam Air Lindi dengan Menggunakan Teknik Oksidasi Lanjut (O3/H2O2)

2021 ◽  
Vol 22 (1) ◽  
pp. 009-017
Author(s):  
Mohamad Rangga Sururi ◽  
Mayang Afi Fadiyah ◽  
Siti Ainun Saleh ◽  
Mila Dirgawati
Keyword(s):  
Mass Transfer ◽  
Dissolved Oxygen ◽  
Flow Rate ◽  
Air Flow ◽  
Colorimetric Method ◽  
Airflow Rate ◽  
Air Flow Rate ◽  
Leachate Treatment ◽  
Grab Sampling ◽  
Filter Disc

ABSTRACT Leachate has complex characteristics, and it is commonly processed biologically in the Leachate Treatment Plant (IPL) in Indonesia. However, as the landfill ages, the leachate becomes less biodegradable. An appropriate technique is needed to treat leachate at IPL, and one of the promising methods is advanced oxidation with O3/H2O2. This study examined the effect of air flow rate on the concentration of residual ozone (KSO) and its efficiency to remove organic compounds using the O3/H2O2 process. Leachate samples were collected as grab samples from TPA Sarimukti Bandung. As much as 1 L of leachate samples were placed in an ozone contactor equipped with a filter disc with a pore size of 100-160 µm. The dose of H2O2 was continuously added to 1.197 g/L. Compressor was used to provide airflow with variations of 2, 3, and 4 L/min. Dissolved Oxygen (DO) was measured to determine the concentration of residual ozone (KSO) and validated by examining KSO measurements with the Indigo colorimetric method. A strong relationship between KSO and DO (R2 = 0.99) was observed at an airflow rate of 4 L/min. The highest ozone mass transfer coefficient (KLa,O3) was recorded at a 4 L/minute flow rate with 0.0022 min-1 at 27 °C.  The best removal efficiency has occurred at the fastest air flow rate (4 L/min) with COD, and UV254 removal was 88.89% and 14.87%, respectively. Keywords: DO, flow variation, KSO, leachate, O3/H2O2, organic, mass transfer   ABSTRAK Karakteristik lindi sangatlah kompleks dan di Indonesia, Instalasi Pengolahan Lindi (IPL) pada umumnya menggunakan sistem pengolahan biologis. Namun demikian, seiring dengan pertambahan umur urugan sampah, lindi semakin tidak biodegradable. Teknik pengolahan tepat diperlukan untuk mengolah lindi di IPL. Salah satu teknik yang sering digunakan adalah oksidasi lanjut dengan O3/H2O2 dengan mentransferkan gas ozon ke dalam air lindi yang diukur sebagai Konsentrasi Sisa Ozon (KSO) dan menambahkan H2O2 untuk meningkatkan pembentukan OH? di dalam air.  Penelitian ini bertujuan untuk mengetahui pengaruh laju aliran udara terhadap KSO serta pengaruhnya terhadap efisiensi penyisihan senyawa organik pada proses O3/H2O2. Sampel lindi diambil secara grab sampling dari TPA Sarimukti Bandung. Sebanyak 1 L sampel ditempatkan pada kontaktor ozon yang dilengkapi filter disc dengan pori berukuran 100-160µm. Dosis H2O2 yang diberikan tetap sebesar 1,197 g/L. Udara dialirkan dengan air compressor dengan variasi debit udara 2, 3, dan 4 L/menit. Pada penelitian ini, pengukuran Dissolved Oxygen (DO) digunakan sebagai pendekatan untuk mengukur KSO. Validasi dilakukan dengan meneliti hubungan antara KSO dan DO dan pengukuran KSO dilakukan dengan metode indigo colorimetric method.  Hasil penelitian menunjukkan KSO dan DO memiliki hubungan yang kuat (R2 = 0,99) pada variasi aliran udara 4 L/menit. Laju aliran udara tercepat terjadi ketika nilai koefisien transfer masa ozon (KLa,O3) mencapai nilai tertinggi (0,0022 menit-1) pada suhu 27 oC. Hasil penelitian membuktikan efisiensi penyisihan COD (88,89%) dan UV254 (14,87%) tertinggi terjadi pada laju aliran udara tercepat selama 180 menit. Kata kunci: DO, aliran udara KSO, lindi, O3/H2O2, organik, transfer masa

scholarly journals Numerical analysis on the dynamic response of a plate-and-frame membrane humidifier for PEMFC vehicles under various operating conditions

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 641-650 ◽  
Author(s):  
Sungho Yun ◽  
Dowon Cha ◽  
Kang Sub Song ◽  
Seong Ho Hong ◽  
Sang Hun Lee ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Relative Humidity ◽  
Dynamic Response ◽  
Flow Rate ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Acceleration ◽  
Dry Air ◽  
Actual Operating

Abstract PEMFC needs to be maintained at an appropriate temperature and humidity in a rapidly changing environment for automobile applications. In this study, a pseudo-multi-dimensional dynamic model for predicting the heat and mass transfer performance of a plate-and-frame membrane humidifier for PEMFC vehicles is developed. Based on the developed model, the variations in the temperature and relative humidity at the dry air outlet are investigated according to the air flow acceleration. Moreover, the dynamic response is analyzed as a function of the amplitude and period of the sinusoidal air flow rate at actual operating conditions. The effects of heat transfer on the dynamic response are more dominant than those of mass transfer. The settling time of the temperature and relative humidity at the dry air outlet decrease with the increase in air flow acceleration. In addition, the variations in the temperature and relative humidity at the dry air outlet increase with the increases in the amplitude and period of the sinusoidal air flow rate.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Modeling and optimization of radish root extract drying as peroxidase source using spouted bed dryer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shahrbanoo Hamedi ◽  
M. Mehdi Afsahi ◽  
Ali Riahi-Madvar ◽  
Ali Mohebbi
Keyword(s):  
Kinetic Parameters ◽  
Flow Rate ◽  
Air Flow ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interactive Effects ◽  
Root Extract ◽  
Air Flow Rate ◽  
Spouted Bed ◽  
Radish Root

AbstractThe main advantages of the dried enzymes are the lower cost of storage and longer time of preservation for industrial applications. In this study, the spouted bed dryer was utilized for drying the garden radish (Raphanus sativus L.) root extract as a cost-effective source of the peroxidase enzyme. The response surface methodology (RSM) was used to evaluate the individual and interactive effects of main parameters (the inlet air temperature (T) and the ratio of air flow rate to the minimum spouting air flow rate (Q)) on the residual enzyme activity (REA). The maximum REA of 38.7% was obtained at T = 50 °C and Q = 1.4. To investigate the drying effect on the catalytic activity, the optimum reaction conditions (pH and temperature), as well as kinetic parameters, were investigated for the fresh and dried enzyme extracts (FEE and DEE). The obtained results showed that the optimum pH of DEE was decreased by 12.3% compared to FEE, while the optimum temperature of DEE compared to FEE increased by a factor of 85.7%. Moreover, kinetic parameters, thermal-stability, and shelf life of the enzyme were considerably improved after drying by the spouted bed. Overall, the results confirmed that a spouted bed reactor can be used as a promising method for drying heat-sensitive materials such as peroxidase enzyme.

Method to Determine an Optimal Air-Flow Rate in Solar Collectors

1979 ◽  
Vol 3 (6) ◽  
pp. 357-362
Author(s):  
H. C. Hewitt ◽  
E. I. Griggs
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Solar Collectors ◽  
Air Flow Rate

Model-Based Analysis of Transient Behavior of Large Scale CFB Boilers

2003 ◽  
Author(s):  
Ari Kettunen ◽  
Timo Hyppa¨nen ◽  
Ari-Pekka Kirkinen ◽  
Esa Maikkola
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Air Flow ◽  
Model Parameters ◽  
Air Flow Rate ◽  
Process Data ◽  
Cfb Boiler ◽  
Flow Rates ◽  
Load Change ◽  
Secondary Air

The main objective of this study was to investigate the load change capability and effect of the individual control variables, such as fuel, primary air and secondary air flow rates, on the dynamics of large-scale CFB boilers. The dynamics of the CFB process were examined by dynamic process tests and by simulation studies. A multi-faceted set of transient process tests were performed at a commercial 235 MWe CFB unit. Fuel reactivity and interaction between gas flow rates, solid concentration profiles and heat transfer were studied by step changes of the following controllable variables: fuel feed rate, primary air flow rate, secondary air flow rate and primary to secondary air flow ratio. Load change performance was tested using two different types of tests: open and closed loop load changes. A tailored dynamic simulator for the CFB boiler was built and fine-tuned by determining the model parameters and by validating the models of each process component against measured process data of the transient test program. The know-how about the boiler dynamics obtained from the model analysis and the developed CFB simulator were utilized in designing the control systems of three new 262 MWe CFB units, which are now under construction. Further, the simulator was applied for the control system development and transient analysis of the supercritical OTU CFB boiler.

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