scholarly journals REMOVAL OF SO2 FROM CONTAMINATED AIR USING A PEAT BIOFILTER / SO2 ŠALINIMAS IŠ UŽTERŠTO ORO NAUDOJANT BIOFILTRĄ SU DURPIŲ ĮKROVA

2013 ◽  
Vol 5 (4) ◽  
pp. 382-387
Author(s):  
Kristina Skemundrytė ◽  
Rasa Vaiškūnaitė
Keyword(s):  
Sulfur Dioxide ◽  
Flow Rate ◽  
Air Flow ◽  
Ambient Air ◽  
Sulfur Compounds ◽  
Air Flow Rate ◽  
Cleaning Efficiency ◽  
Air Cleaning ◽  
Peat Biofilter ◽  
Cleaning Technology

About 64 thousand tons of contaminated air is annually released into ambient air. More than 30% of such pollution includes toxic sulfur compounds. The article discusses the properties of biofiltration - biological air cleaning technology. Research was performed using a biofilter produced in the laboratory at Vilnius Gediminas Technical University. During testing, ambient air contaminated with sulfur dioxide was pulled through biomedia with a division of Thiobacillus microorganisms, and calculations of cleaning efficiency were performed. Besides, the efficiency of the charged peat biofilter (changing technical characteristics of the air flow rate, number of layers and value of pollutant concentration), depending on the nature of the investigated sulfur compounds and their concentrations, was determined. The biofilter improves the efficiency of air cleaning when the air flow rate reduces from 0,1 to 0,02 m/s (e.g. when sulfur dioxide is used for treating the air flow rate under the initial concentration C = 15 mg/m³, the efficiency of the filter is equal to E = 96,3%). Santrauka Didžiausia šiais laikais išsivysčiusių ir besivystančių šalių problema yra greitai besiplečiančių pramonės ir energetikos sektorių į aplinkos orą išmetami cheminiai junginiai (apie 64 tūkst. tonų per metus), iš kurių apie 30 % – žmogui nuodingi ir aplinkai neigiamą poveikį darantys sieros junginiai. Trumpai aptariama biologinio oro valymo privalumai, pagrindinės pasirinktõs durpių bioįkrovos charakteristikos, pateikiama taikyta metodika bei sieros dioksido valymo iš oro eksperimentų rezultatai, aprašomas biofiltracijos procesas. Biofiltro oro valymo efektyvumas didėja mažinant valomo oro srauto greitį nuo 0,1 iki 0,02 m/s (valant sieros dioksidu užterštą orą, kai pradinė teršalo koncentracija C = 15 mg/m³), filtro efektyvumas yra E = 96,3 %.

scholarly journals CLEANING OF H2S FROM POLLUTED AIR USING PEAT BIOFILTER

2020 ◽  
Vol 12 (0) ◽  
pp. 1-5
Author(s):  
Rasa Vaiškūnaitė
Keyword(s):  
Sulfur Dioxide ◽  
Ambient Air ◽  
Sulfur Compounds ◽  
Air Flow Rate ◽  
Cleaning Efficiency ◽  
Air Cleaning ◽  
Number Of Layers ◽  
Peat Biofilter ◽  
Cleaning Technology ◽  
University Laboratory

Every year about 64 thousand tons of polluted air is being released to the ambient air. More than 30% of this pollution consists of toxic sulfur compounds. The properties of biological air cleaning technology – biofoltration with peat media – has been discussed in the article. Research was performed by using biofilter from Vilnius Gedimi-nas technical university laboratory. During testing ambient air, polluted with sulfur dioxide, was pulled through the biomedia with division of Thiobacillus microorganisms and calculations of cleaning efficiency were performed. Was determined the efficiency of peat biofilter charge (changing the technical characteristics of the air flow rate, the number of layers, the pollutant concentration value) depending on the nature of the investigated sulfur compounds and their concentrations.

scholarly journals Parametric study of condensation at heating, ventilation, and air-conditioning duct's external surface

2017 ◽  
Vol 39 (3) ◽  
pp. 328-342 ◽  
Author(s):  
Dileep Kumar ◽  
Abdul Ghafoor Memon ◽  
Rizwan Ahmed Memon ◽  
Intizar Ali ◽  
Natasa Nord
Keyword(s):  
Air Temperature ◽  
Flow Rate ◽  
Air Conditioning ◽  
External Surface ◽  
Air Flow ◽  
Ambient Air ◽  
Air Flow Rate ◽  
Dew Formation ◽  
Insulation Thickness ◽  
Air Speed

The compression of insulation causes around a heating, ventilation, and air-conditioning duct usually resulted in dew formation around the outer surfaces because of low temperature, which causes significant energy and financial losses. The parameters such as supply air flow rate, supply air temperature, ambient air speed, and the convective heat transfer coefficient (ho) plays significant role in dew formation. In this paper, the parametric study is performed to investigate the effects of these parameters on the external surface temperature of the duct to avoid condensation. A mathematical model is developed to quantify these effects using preliminary data obtained from the heating, ventilation, and air-conditioning system of a pharmaceutical company. The results reveal that external surface temperature increases with an increase in insulation thickness and supply air temperature, whereas it decreases with higher supply air flow rate. It is estimated that the minimum insulation thickness at joint and bend should be maintained between 15–55 and 15–35 mm, respectively, with a variation in ho between 6 and 22 W/m2K to avoid condensation. Additionally, it is estimated that air flow rate should be greater than 1.4 m3/s at 10 W/m2 K and 2.2 m3/s at 22 W/m2 K. Similarly, the ambient air speed should be greater than 2.8 m/s at 6 W/m2 K, respectively. Practical application: Building services engineers have a paucity of information on the effects of the compression of heating, ventilation, and air-conditioning duct thermal insulation. It can cause condensation that will adversely affect the insulation material, thereby increasing the maintenance cost as well increasing the heat loss from the duct so affecting the conditions of supply air. Proper insulation thickness and operating parameters are important for building owners and operators to control ongoing expenses of buildings. This paper seeks to quantify the effect of insulation compression to improve understanding so that this important area may be properly considered by the building services engineer.

scholarly journals Effect of a ambient air flow rate on deposition rate of droplets on spray chamber.

1986 ◽  
Vol 12 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Shoji Tanno ◽  
Takeshi Kawasaki ◽  
Takatoshi Miura ◽  
Shigemori Ohtani
Keyword(s):  
Deposition Rate ◽  
Flow Rate ◽  
Air Flow ◽  
Ambient Air ◽  
Spray Chamber ◽  
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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