scholarly journals The Effect of Firewood Moisture Content on the Atmospheric Thermal Load by Flue Gases Emitted by a Boiler

2019 ◽  
Vol 11 (1) ◽  
pp. 284 ◽  
Author(s):  
Ladislav Dzurenda ◽  
Adrian Banski
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Thermal Load ◽  
Combustion Process ◽  
Flue Gases

In this paper, we present an analysis on the effect of the moisture content of firewood on the atmospheric thermal load created by the heating of flue gases with temperatures of tfg = 120–200 °C, emitted by a boiler when wood with moisture content of W = 10%–60% is combusted. The load of the atmosphere created by the heat of the flue gases with temperatures of ts = 120 °C from the boiler, where dried wood with the moisture content of W = 10% is combusted, is Q = 9.2 MJ·GJ−1. The atmospheric thermal load caused by flue gases with the temperature of ts = 200 °C, resulting from the combustion process of wet firewood with a moisture content of W = 60%, is 3.8 times higher compared with the above-mentioned conditions. The heating of water vapor from the evaporated water occurring in combusted wood, as well as the heat of the heated nitrogen and unoxidized oxygen in the combustion air delivered to the furnace of a firewood boiler, are considered to be reasons for the increasing atmospheric thermal load caused by the heating of flue gases, resulting from the combustion of wood with higher moisture content.

Influence of Vegetation Moisture on Combustion of Pyrolysis Gases in Wildland Fires

2011 ◽  
Author(s):  
Selina C. Dover ◽  
Ambarish R. Dahale ◽  
Babak Shotorban ◽  
Shankar Mahalingam ◽  
David R. Weise
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Mole Fraction ◽  
Flame Structure ◽  
Combustion Process ◽  
Fuel Moisture ◽  
Wildland Fires ◽  
Effect Of Moisture ◽  
Fuel Moisture Content ◽  
Pyrolysis Gases

Since wildland fires occur in living vegetation, the fuel moisture content must be considered in order to correctly predict the behavior of the fire. One facet of combustion of pyrolysis gases that has not been considered in previous research is the effect of moisture on the combustion process. This effect is investigated by using CHEMKIN software to study an opposed diffusion flame model for three pyrolysis fuels relevant to wildfires. The effect of moisture on flame structure is investigated by varying the mole fraction of water vapor in the fuels, with air as oxidizer. In all cases, the flame extinguishes when the water mole fraction is between 0.55 and 0.65. O2 and H are the only components that exhibit a significant change in concentration under these conditions.

Numerical Simulation on Moisture Influence to MSW Combustion

2014 ◽  
Vol 1006-1007 ◽  
pp. 181-184
Author(s):  
Zhu Sen Yang ◽  
Xing Hua Liu ◽  
Shu Chen
Keyword(s):  
Numerical Simulation ◽  
Moisture Content ◽  
Flue Gas ◽  
Combustion Process ◽  
Average Temperature ◽  
Excess Air ◽  
Heat Value ◽  
Moisture Influence ◽  
Excess Air Coefficient ◽  
Combustible Gases

The combustion process of municipal solid waste (MSW) in a operating 750t/d grate furnace in Guangzhou was researched by means of numerical simulation. The influence of MSW moisture content on burning effect was discussed. The results show that: with the moisture content dropped from 50% to 30%, the heat value could be evaluated from 13.72% to 54.91% and the average temperature in the furnace could be promoted 90-248°C. However, the combustible gases and particle in the flue gas of outlet would take up a high proportion since lacking of oxygen would lead to an incomplete combustion. The excess air coefficient should be increased to 2.043~2.593 in order to ensure the flue gas residence time more than 2s and temperature in the furnace higher to 800°C.

scholarly journals RESEARCH OF INFLUENCE OF AIR TEMPERATURE ON THE LEVEL OF NITROGEN OXIDES IN SMOKE GASES OF BOILER PLANTS

2019 ◽  
Vol 9 (4) ◽  
pp. 27-32
Author(s):  
Olga A. BALANDINA ◽  
Svetlana M. PURING
Keyword(s):  
Mathematical Modeling ◽  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Flue Gas ◽  
Software Package ◽  
Flame Temperature ◽  
Combustion Process ◽  
Flue Gases ◽  
Oxidizing Agent ◽  
Mixture Formation

The analysis of the values of the concentrations of the formed nitrogen oxides and the temperatures of the jet plume under various conditions of mixture formation is carried out. The plots of the distribution of torch temperatures and concentrations of nitric oxide in the calculated area for oxidizer temperatures of 20, 60, 100, 150, and 200 ° C were obtained and analyzed. Mathematical modeling of the gaseous fuel combustion process was carried out using the FlowVision software package. An analysis of the results showed that a decrease in the temperature of the air supplied as an oxidizing agent leads to a significant decrease in the concentration of nitrogen oxides in flue gases, while not significantly affecting the change in the flame temperature. The research results can be used to solve the problems of optimizing boiler plants, in order to reduce harmful flue gas emissions. Further modeling is planned to determine the dependence of the influence of various factors on the degree of formation of nitrogen oxides in the flue gases of boiler plants.

scholarly journals Characteristics of Woody Cutting Waste Briquette with Paper Waste Pulp as Binder

2020 ◽  
Vol 190 ◽  
pp. 00030
Author(s):  
Qurrotin Ayunina Maulida Okta Arifianti ◽  
Azmi Alvian Gabriel ◽  
Syarif Hidayatulloh ◽  
Kuntum Khoiro Ummatin
Keyword(s):  
Moisture Content ◽  
Ignition Time ◽  
Combustion Process ◽  
Calorific Value ◽  
Volatile Matter ◽  
Proximate Analysis ◽  
Hydraulic Press ◽  
Combustion Characteristic ◽  
Paper Waste ◽  
Iron Mold

The current research aimed to increase the calorific value of woody cutting waste briquette with paper waste pulp as binder. There were three different binder variation used in this study, they are 5 %, 10 %, and 15 %. To create a briquette, a cylindrical iron mold with diameter of 3.5 cm and height of 3 cm and a hydraulic press with 2 t power were applied. The physical characteristics of the combination woody waste briquette and paper waste pulp, such as moisture content, ash content, volatile matter and carbon fix were examined using proximate analysis. The calorific value of briquetted fuel was tested by bomb calorimeter. The combustion test was performed to determine the combustion characteristic of briquettes, for example initial ignition time, temperature distribution, and combustion process duration. The general result shows that the calorific value of briquette stood in the range of 4 876 kCal kg–1 to 4 993 kCal kg–1. The maximum moisture content of briquette was 5.32 %. The longest burning time was 105 min.

scholarly journals Study on the Microscopic Mechanism of Spontaneous Combustion and Oxidation Kinetics of Water-Leached Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Naifu Cao ◽  
Gang Wang ◽  
Yuntao Liang
Keyword(s):  
Kinetic Model ◽  
Moisture Content ◽  
Spontaneous Combustion ◽  
Water Immersion ◽  
Combustion Process ◽  
Oxidation Kinetic ◽  
Oxidation Mechanism ◽  
Temperature Oxidation ◽  
Before And After ◽  
Spontaneous Combustion Of Coal

In this article, a series of experiments have been carried out to study the spontaneous combustion and oxidation mechanism of coal after water immersion and investigate its tendency to spontaneous combustion, analyze the difficulty of spontaneous combustion of coal samples under different water immersion conditions, and establish a kinetic model of water immersion coal oxidation (taking the Bulianta 12# coal as a case study). They rely on physical oxidation adsorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry, and oil bath heating. SEM has been used to analyze the characteristics of coal pore structure under different water immersion conditions (water-saturated coal samples under different water loss conditions until the coal samples are completely dried); FTIR served to investigate the characteristics of the molecular chemical structure of the coal surface before and after the coal is immersed in water. Through programmed temperature oxidation experiments combined with FTIR analyses and gas chromatographic (GC) analysis of gaseous products, it has been possible to study the changes of molecular structure and gas products on the surface of coal samples at different temperatures and water immersion conditions. The oxidation reaction rate of the 12# coal samples of Shendong Mine’s Bulianta Mine under different water content conditions during the spontaneous combustion process has been quantitatively studied. The difficulty of spontaneous combustion of coal samples has been correspondingly addressed. A kinetic model from the perspective of oxygen consumption has been proposed. Thermogravimetry-differential scanning calorimetry (TG-DSC) has been used to analyze and study the exothermal oxidation process before and after coal immersion. From the perspective of the exothermic intensity of the coal-oxygen reaction, an oxidation kinetic model for immersed coal samples has been developed to qualitatively determine its spontaneous combustion tendency. Results have shown that the increase in the specific surface area increases the risk of spontaneous combustion, and coal samples after soaking and drying have a stronger tendency to spontaneous combustion than raw coal. The moisture content of the coal sample leading to the easiest ignition conditions is 16.05%. Regardless of the moisture content, the critical temperature is maintained at 65–75°C, and the temperature of the left coal in the goaf should be prevented from exceeding this critical value.

scholarly journals Increased Comfort of Polyester Fabrics

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 3010
Author(s):  
Meritxell Martí ◽  
Jaime Gisbert-Paya ◽  
Mª Ángeles Bonet-Aracil ◽  
Petar Jovančić ◽  
Manuel J. Lis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Microwave Irradiation ◽  
Alkaline Treatment ◽  
Negative Ion ◽  
Experimental Conditions ◽  
Hygroscopic Properties ◽  
Treatment Conditions ◽  
Moisture Increase ◽  
Subsequent Improvement

The hydrophilicity of fibers is directly related to the comfort of a fabric and represents one of the most important aspects of a textile. Therefore, polyester (PES) modification has focused on an increase in moisture content and a subsequent improvement of the user’s experience. Based on the glycerol hygroscopic properties, the main objective has been the enhancement of the hydrophilicity of polyester by glycerol treatments. Furthermore, microwave irradiation and alkaline treatment have been applied, in order to increase glycerol adhesion. Treated PES samples were characterized by performing moisture content, negative ion, water diffusion and water vapor resistance analyses. The effect of different treatment conditions such as bath ratio (1/10 or 1/15), temperature (40, 60 or 100 °C), time (2 or 5 min) and microwave radiation intensity (300 or 500 W) was evaluated. The moisture content of treated PES results indicated that by decreasing the bath ratio and increasing the time and temperature the moisture gain can reach almost 14%, which can be easily related to increases in the weight of the fiber. The treatment with alkali was done and led to the highest moisture increase. Treatment with 500 W microwave irradiation led to higher glycerol retention after rinsing. Different experimental conditions were applied to the glycerol-treated PES fabrics, and a clear improvement in moisture content was obtained increasing the comfort. The results were compared with the ones obtained for cotton and wool, where the moisture is higher than non treated PES.

scholarly journals Thermo-physiological properties of woven structures in wet state

2018 ◽  
Vol 69 (04) ◽  
pp. 298-303
Author(s):  
BOUGHATTAS AMAL ◽  
BENLTOUFA SOFIEN ◽  
HES LUBOS ◽  
AZEEM MUSADDAQ ◽  
FAYALA FATEN
Keyword(s):  
Thermal Properties ◽  
Water Vapor ◽  
Moisture Content ◽  
Water Vapor Permeability ◽  
Woven Fabric ◽  
Weft Yarn ◽  
Vapor Permeability ◽  
Skin Contact ◽  
Woven Structures ◽  
Woven Structure

The utmost parameters that measure the thermo-physiological comfort of garments are thermal conductivity, thermal absorptivity and water vapor permeability. In this paper, thermo-physiological comfort was studied with different weave design and moisture content. Thermal properties and water vapor permeability in dry and wet state of all fabric samples were determined by ALAMBETA and Permetest respectively. Results showed that the weaving structure and yarn composition in weft were closely related to the thermal properties and water vapor permeability in presence of moisture. Woven fabric samples were constructed by varying the weave design and weft composition. In wet state, moisture content up to 20%, weave structures exhibited non-significant behavior for thermal properties due to air fraction. As the moisture content enhanced, woven structure made with polyester weft yarn provided cooler feeling with skin contact.

The Effect of Lauric Acid Addition on Characteristics of Biocomposite Edible Film

2021 ◽  
Vol 1044 ◽  
pp. 191-200
Author(s):  
Emma Rochima ◽  
Nur Silmi Nafisah ◽  
Rosidah ◽  
Iis Rostini ◽  
Subaryono
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Lauric Acid ◽  
Transmission Rate ◽  
Total Solid ◽  
Edible Film ◽  
Film Material ◽  
Percent Elongation ◽  
Acid Addition ◽  
Water Vapor Transmission

The biocomposites were prepared from chitosan, carragenan and modified tapioca with lauric acid addition. The biocomposite were used as edible film material thus improving the mechanical characteristics. The purpose of this study was to determine the amount of lauric acid addition that produced biocomposites with the best characteristics. This study used experimental method. The different concentration of lauric acid used as the treatment was 0%, 10%, 20%, 30%, 40% from total solid of hydrocolloids materials (w/w). Data were analyzed statistically using the F test (ANOVA test) with confidence level of 95%. The results showed more than 10% addition of lauric acid decreased the value of moisture content, tensile strenght, percent elongation and water vapor transmission but increase thickness, opacity and transparency value. The addition of 10% lauric acid produced biocomposite with the best characteristics according to JIS (Japanese Industrial Standard) which had the moisture content of 42.65%, thickness of 0.047 mm, tensile strength of 13.8 MPa, percent elongation of 29.2%, water vapor transmission rate of 8.5 g/m2/day, opacity 8.9% and transparency 7.5. This research used renewable and biodegradable materials that can be applied to produce edible packaging with the best characteristics and eco-friendly.

A Hybrid Technique for the Performance Optimization in the Combustion Process of a Power Plant Boiler: An Efficient ANNSSA Technique

2021 ◽  
Author(s):  
P. V. Narendra Kumar ◽  
Ch. Chengaiah ◽  
P. Rajesh ◽  
Francis H. Shajin
Keyword(s):  
Power Plant ◽  
Performance Optimization ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Flue Gases ◽  
Unburned Carbon ◽  
Hybrid Technique ◽  
Power Plant Boiler ◽  
Artificial Neural Network Ann ◽  
Plant Boiler

In this paper presents a hybrid method for optimization process of combustion in power plant boiler. ANSSA scheme will be joint implementation of Artificial Neural Network (ANN) as well as Salp Swarm Optimization Algorithm (SSA) known ANNSSA. Here, ANN training process will be enhanced by using the SSA calculating. The optimization of economic parameters reduces excess air level and performs combustion efficiency at boiler system. Due to the operation of service boiler, oxygen content of flue gases is one of the significant factors which influence the efficiency of boiler, and influence each other to other thermal parameters of economic like temperature of flue gases combustion, unburned carbon at fly ash slag and consumption of coal power supply. The combustion performance denotes a saving at operating costs of boiler. ANNSSA method evolved for process of combustion to enhance the implementation and efficiency of the power plant boiler. At that time, ANNSSA technique is implemented at MATLAB/Simulink work platform as well as implementation is evaluated using existing techniques.

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