Thermal plasma treatment of stormwater detention pond sludge

2008 ◽  
Vol 80 (9) ◽  
pp. 1993-2002 ◽  
Author(s):  
Jen-Shih Chang ◽  
Helena O. L. Li ◽  
Yiping Guo
Keyword(s):  
Plasma Treatment ◽  
Flow Rate ◽  
Thermal Plasma ◽  
Treatment Time ◽  
Air Flow ◽  
Sediment Quality ◽  
Air Flow Rate ◽  
Element Analysis ◽  
Weight Percentage ◽  
Detention Pond

A thermal plasma treatment experiment was conducted on stormwater detention pond sludge. The original sludge compositions were analyzed by neutron activation multi-element analysis. Thirty-two elements were detected in the sludge samples, and nine of them were below detection limit. The assessment of Zn, As, Mn, and Fe concentrations against the Ontario Ministry of Environment's Sediment Quality Guidelines indicated a marginal-to-significant pollution, and the concentration of Cr presented a gross pollution. After thermal plasma treatment, the mean weight percentage removal at 0 and 2 L/min of air flow rates was 2.78 ± 0.51 and 3.85 ± 1.35 %, respectively. The maximum weight removal of 5.87 % was achieved with 2 L/min air flow rate and 2 h of treatment time. Reduction of total organic carbon (TOC) increased with increasing treatment time and air flow rate. Eight gas compounds, CO, CO2, NO, NO2, NOx, SO2, H2S, and CxHy were measured and observed during the treatment process.

scholarly journals Plasma Degradation of Pesticides on the Surface of Corn and Evaluation of Its Quality Changes

2021 ◽  
Vol 13 (16) ◽  
pp. 8830
Author(s):  
Hongxia Liu ◽  
Dingmeng Guo ◽  
Xinxin Feng
Keyword(s):  
Plasma Treatment ◽  
Flow Rate ◽  
Treatment Time ◽  
Starch Content ◽  
Air Flow ◽  
Acid Value ◽  
Quality Changes ◽  
Air Flow Rate ◽  
Acceptable Range ◽  
Significant Difference

Plasma is a surface decontamination tool that is widely used in the food fields for pesticide degradation. In this study the effect of plasma on pesticide elimination from the surface of corn and the corn quality changes were tested as functions of power, air flow rate, treatment time, and frequency. Results indicated that plasma treatment for 60 s at 1000 mL·min−1 air flow rate, power of 20 W, and frequency of 1200 Hz, achieved the largest degradation efficiency up to 86.2% for chlorpyrifos and 66.6% for carbaryl, both of which were below the maximum residues limit of grains. Most importantly, after plasma treatment, there was a remarkable decrease (p < 0.05) in moisture content and starch content for treated corn compared with control. The acid value for treated corn showed a prominent increase (p < 0.05), but within the acceptable range of the standard. The vitamin B2 content of treated corn did not show a significant difference (p > 0.05). All results of this study demonstrated that plasma treatment is a promising technology with the ability to remove pesticide residues on corn while maintaining its quality within acceptable limits.

Experimental Analysis on Characteristics of a Water-Cooled Non-Thermal Plasma Reactor

2013 ◽  
Vol 278-280 ◽  
pp. 128-133
Author(s):  
Kang Hua Li ◽  
Yi Xi Cai ◽  
Xiao Hua Li ◽  
Wen He Han ◽  
Yun Xi Shi ◽  
...  
Keyword(s):  
Flow Rate ◽  
Thermal Plasma ◽  
Plasma Reactor ◽  
Air Flow ◽  
Discharge Power ◽  
Discharge Zone ◽  
Operating Frequency ◽  
Air Flow Rate ◽  
Surface Temperatures ◽  
Non Thermal Plasma

Characteristics of a water-cooled non-thermal plasma (NTP) reactor used to reduce diesel emissions were experimentally studied. The effects of working voltage, operating frequency and air flow rate on discharge power and concentrations of O3 and NO2 generated by NTP system were investigated at different surface temperatures of discharge zone. The experimental results show that, the discharge power of the reactor would increase with the increasing of working voltage, operating frequency and surface temperatures; air flow rate had little influence on discharge power; variation of O3 and NO2 concentration were different with the increasing of working voltage and operating frequency at different surface temperatures of discharge zone; when the surface temperature of discharge zone was constant, concentrations of O3 and NO2 increased firstly and then declined with the increasing of air flow rate; and concentrations of O3 and NO2 were higher at lower temperature.

scholarly journals Theoretical calculation and simulation of surface-modified scalable silicon heat sink for electronics cooling

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4181-4187
Author(s):  
Yichi Zhang ◽  
Shinichi Saito ◽  
Yoshishige Tsuchiya ◽  
Yeliang Wang
Keyword(s):  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Air Flow ◽  
Electronics Cooling ◽  
Heat Sinks ◽  
Air Flow Rate ◽  
Element Analysis ◽  
Microfabrication Technology ◽  
Surface Modified

A surface-modified scalable heat sink that can be fabricated by applying silicon microfabrication technology has been proposed in this paper. Theoretical estimation of the heat sink thermal resistance is based on the heat sink with overall size of 1 cm ? 1 cm ? 1 cm, and four kinds of structure with various total number of grooves on the surface of fins have been investigated. Finite element analysis has been conducted by using COMSOL Multiphysics where fluid dynamics and heat transfer are taken into account. As a result, the lowest heat sinks thermal resistance of 6.84?C per Watt is achieved for the structure with a larger fin area (13.1 cm2) and a higher inlet air flow rate (4 m/s), suggesting an optimum fin area depending on the 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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