Pyrolysis and Oxidative Pyrolysis of Polystyrene

1993 ◽  
Author(s):  
Ashwani K. Gupta ◽  
Eugene L. Keating
Keyword(s):  
Thermal Destruction ◽  
Pyrolysis Temperature ◽  
Flame Temperature ◽  
Combustion Process ◽  
Chemical Species ◽  
Advanced Combustion ◽  
Oxidative Pyrolysis ◽  
Product Gas ◽  
Different Temperatures ◽  
Gas Volume

Abstract Equilibrium thermochemical calculations of polystyrene are presented here under conditions of pyrolysis and oxidative pyrolysis. Oxidative pyrolysis is examined using both air and oxygen for varying moisture content in the polystyrene. The pyrolysis of polystyrene at different temperatures prior to its oxidative pyrolysis provided significantly different results. Product gas volume and flame temperature is significantly affected by the pyrolysis temperature, nature and amount of the oxidant and the amount of moisture in the waste. Results reveal significant effect of controlled combustion on the amount and nature of the chemical species formed. The results also reveal that advanced combustion process can significantly reduce the extent of post processing of gases required, and hence the size of the equipment, for achieving environmentally acceptable thermal destruction system of the solid wastes.

Modelling adiabatic flame temperature for methane with an overview for advanced combustion process: flameless combustion

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Anis Imakhlaf ◽  
Abdelhadi Beghidja
Keyword(s):  
Flame Temperature ◽  
Combustion Process ◽  
Flameless Combustion ◽  
Environmental Aspect ◽  
Equivalent Ratio ◽  
Rich Mixture ◽  
The Third ◽  
Advanced Combustion ◽  
Mathematical Equations ◽  
Optimal Values

Abstract In this study, we have carried out to modeling by mathematical equations the environment of the combustion chamber under some conditions using the software MATLAB in order to make an adequate algorithm of resolution and get solution of the different equations that taken part in the phenomenon of combustion, so the first was to identifies the kind of the fuel to use in that model (taking Methane as fuel combustion) and minimizing the reduction of novice gas burned is in priority, for this, we want to establish the optimal values to take to preserve the environment, especially from CO2 and CO emissions, secondly, its nature according to the equivalent ratio (lean, stoichiometric or rich mixture), all variations of equivalent ratio, the third idea is to retrace the ways of a different product of the reaction and see their variations compared to the equivalent ratio, once traced, we can improvise which exact place in the reaction, a product will be finished either in the form of a gas or to decompose in order to bind to another and form another component. We also discussed the percentage of O2 and H2O emissions for an interesting viewpoint of the environmental aspect of hydrocarbon’s chemical reaction. Another additional part will be dedicated to the process of flameless combustion to write its mathematical equation, compare it with the so-called traditional one, and see the variations in the temperature according to the equivalent ratio.

Influence of PVC on the Product Composition of Solid Waste During Thermal Destruction

1994 ◽  
Author(s):  
A. K. Gupta ◽  
E. Ilanchezhian ◽  
E. L. Keating
Keyword(s):  
Solid Waste ◽  
Thermal Destruction ◽  
Chemical Nature ◽  
Excess Enthalpy ◽  
General Trend ◽  
Flame Temperature ◽  
Chemical Species ◽  
Chemical Properties ◽  
Plastic Waste ◽  
Very High

Abstract Equilibrium thermochemical calculations of a mixture of non-plastic and plastic surrogate solid waste are presented here under conditions of pyrolysis and combustion. The non-plastic waste is assumed to be cellulose while the plastic waste constituents contained the following different kinds of materials: polyethylene, polyvinyl chloride, polystyrene, polypropylene, polyethylene tetraphthalic, nylon, latex in the form of rubber, polyurethane, acetate and cellophane. The cellulose represents organic portion of the waste such as paper and cardboard. The mole fractions of different stable and unstable compounds formed during pyrolysis are significantly affected by the chemical properties of the waste. In general the amount of CO and H2O was found to remain very high at temperatures up to 2000K. while the CO2, H2O and CH4 decreased with the increase in temperature. The general trend with combustion at different mole fractions of oxygen was to achieve an increase of CO2, H2O, NO and NO2 while the concentrations of CH4, H2, CO and HCl showed a systematic decrease. The concentration and amount to different compounds formed were significantly affected with the amount of air and the chemical nature of the waste. The adiabatic flame temperature is significantly affected by the chemical composition of the plastic under conditions of combustion in air. Plastics yield significantly higher temperatures than the mixture of plastic and non-plastic waste. Experimental results showed good trend with the calculated results. Pyrolysis of waste at higher temperatures followed by combustion of resulting gases yield higher flame temperature and provides excess enthalpy of flames. The results show significant effect of controlled combustion on the amount and nature of chemical species formed as well as the subsequent flame temperature. This information can assist in developing strategies in the design and operation of facilities being used for the permanent disposal of wastes containing varying amounts of plastics.

Study of Combustion Characteristics of Ethanol at Different Dilution With the Carrier Gas

2014 ◽  
Author(s):  
Binash Imteyaz ◽  
Mohamed A. Habib
Keyword(s):  
Carbon Dioxide ◽  
Flue Gas ◽  
Carbon Capture ◽  
Liquid Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Conventional Combustion ◽  
Gas Volume

With the ever rising concern of global warming, carbon capture is gaining the reputation of one of the most challenging fields of research. A very promising technology to capture CO2 is oxy-combustion. Oxy-combustion offers several advantages over conventional combustion technologies, such as flue gas volume reduction, high combustion efficiency, low fuel consumption and significant reduction in NOx emissions. Liquid fuel is available and it is the most widely used source of energy in the world. Easy handling and transportation, less storage volume and higher flame temperature are some of the features of liquid fuel which give it an upper hand over other sources. In this study, an experimental work on oxygen enriched combustion of ethanol in a vertical reactor by Lacas F. et. al. has been modeled numerically. Non-premixed model using Probability Density Function has been incorporated to simulate the combustion process of ethanol droplets. Predicted combustion characteristics are found to be in good compliance with the experimental data. In addition to this, effects of dilution of carbon-dioxide in oxygen on the flame properties have also been presented. Combustion of ethanol in oxygen-carbon dioxide environment has been compared with that of the conventional air environment.

Study of Combustion Characteristics of Ethanol at Different Dilution With the Carrier Gas

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Binash Imteyaz ◽  
Mohamed A. Habib
Keyword(s):  
Carbon Dioxide ◽  
Flue Gas ◽  
Carbon Capture ◽  
Liquid Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Gas Volume ◽  
Probability Density Function Pdf

With the ever-rising concern of global warming, carbon capture is gaining the reputation of one of the most challenging fields of research. A very promising technology to capture CO2 is oxy-combustion. Oxy-combustion offers several advantages over conventional combustion technologies, such as flue–gas volume reduction, high combustion efficiency, low fuel consumption, and significant reduction in NOx emissions. Liquid fuel is available and it is the most widely used source of energy in the world. Easy handling and transporting, less storage volume and higher flame temperature are some of the features of liquid fuel which give it an upper hand over other sources. In this study, an experimental work on oxygen enriched combustion of ethanol in a vertical reactor by Lacas et al. (2005, “Experimental Study of Air Dilution in Oxy-Liquid Fuel Flames,” Proc. Combust. Inst., 30(2), pp. 2037–2045) has been modeled numerically. Nonpremixed model using probability density function (PDF) has been incorporated to simulate the combustion process of ethanol droplets. Predicted combustion characteristics are found to be in good compliance with the experimental data. In addition to this, effects of dilution of carbon dioxide in oxygen on the flame properties have also been presented. Combustion of ethanol in oxygen–carbon dioxide environment has been compared with that of the conventional air environment.

Analysis of chemical effects on reflected-shock flow fields in combustible gas

1985 ◽  
Vol 160 ◽  
pp. 29-45 ◽  
Author(s):  
Yasunari Takano ◽  
Teruaki Akamatsu
Keyword(s):  
Heat Release ◽  
Chemical Reactions ◽  
Induction Time ◽  
Combustion Process ◽  
Chemical Species ◽  
Flow Fields ◽  
Rate Equations ◽  
Reflected Shock ◽  
Combustible Gas ◽  
Analytical Results

This paper analyses effects of chemical reactions on reflected-shock flow fields in shock tubes. The method of linearized characteristics is applied to analyse gasdynamic disturbances due to chemical reactions. The analysis treats cases where combustible gas is highly diluted in inert gas, and assumes that flows are one-dimensional and that upstream flows in front of the reflected-shock waves are in the frozen state. The perturbed gasdynamic properties in the reflected-shock flow fields are shown to be expressible mainly in terms of a heat-release function for combustion process. In particular, simple relations are obtained between the heat-release function and the physical properties at the end wall of a shock tube. As numerical examples of the analysis, the present formulation is applied to calculate gasdynamic properties in the reflected-shock region in a H2–O2–Ar mixture. Procedures are demonstrated for calculation of the heat-release function by numerically integrating rate equations for chemical species. The analytical results are compared with rigorous solutions obtained numerically by use of a finite-difference method. It is shown that the formulation can afford exact solutions in cases where chemical behaviours are not essentially affected by gasdynamic behaviours. When the induction time of the combustion process is reduced to some extent owing to gasdynamic disturbances, some discrepancies appear between analytical results and rigorous solutions. An estimate is made of the induction-time reduction, and a condition is written down for applicability of the analysis.

Effects of Zn on Pyrolysis Characteristics of Shenhua Lignite

2014 ◽  
Vol 1008-1009 ◽  
pp. 247-251
Author(s):  
Wipawan Sangsanga ◽  
Chuan Na ◽  
Jin Xiao Dou ◽  
Jiang Long Yu
Keyword(s):  
Pyrolysis Temperature ◽  
Fixed Bed ◽  
Coal Pyrolysis ◽  
Pyrolysis Gas ◽  
Gaseous Products ◽  
Pyrolysis Characteristics ◽  
Maximum Value ◽  
Product Gas ◽  
Zn Content ◽  
Catalytic Effects

The catalytic effects of Zn on the release of the gaseous products during pyrolysis of Shenhua lignite was investigated by using a fixed-bed quartz reactor. The product gas compositions from the coal pyrolysis were analyzed by a gas chromatography (GC). Experimental results show that Zn had noticeable catalytic effects on lignite pyrolysis. With the increase in Zn content, lignite weight loss increases during pyrolysis. However, there was an optimum content for amount Zn into the coal. Pyrolysis temperature had a great impact on the composition of pyrolysis gas. As the pyrolysis temperature increased, char yield decreased and gas yield increased. There existed a temperature that tar yield reached its maximum value.

Chemical Kinetic Analysis of a Flameless Gas Turbine Combustor

2008 ◽  
Author(s):  
G. Arvind Rao ◽  
Yeshayahou Levy ◽  
Ephraim J. Gutmark
Keyword(s):  
Combustion Chamber ◽  
Kinetic Analysis ◽  
Gas Turbine ◽  
Flame Temperature ◽  
Plug Flow ◽  
Combustion Process ◽  
Chemical Reactor ◽  
Chemical Kinetic ◽  
Combustion Regime ◽  
Reactor Model

Flameless combustion (FC) is one of the most promising techniques of reducing harmful emissions from combustion systems. FC is a combustion phenomenon that takes place at low O2 concentration and high inlet reactant temperature. This unique combination results in a distributed combustion regime with a lower adiabatic flame temperature. The paper focuses on investigating the chemical kinetics of an prototype combustion chamber built at the university of Cincinnati with an aim of establishing flameless regime and demonstrating the applicability of FC to gas turbine engines. A Chemical reactor model (CRM) has been built for emulating the reactions within the combustor. The entire combustion chamber has been divided into appropriate number of Perfectly Stirred Reactors (PSRs) and Plug Flow Reactors (PFRs). The interconnections between these reactors and the residence times of these reactors are based on the PIV studies of the combustor flow field. The CRM model has then been used to predict the combustor emission profile for various equivalence ratios. The results obtained from CRM model show that the emission from the combustor are quite less at low equivalence ratios and have been found to be in reasonable agreement with experimental observations. The chemical kinetic analysis gives an insight on the role of vitiated combustion gases in suppressing the formation of pollutants within the combustion process.

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 Chemiluminescence analysis of the effect of butanol-diesel fuel blends on the spray-combustion process in an experimental common rail diesel engine

2015 ◽  
Vol 19 (6) ◽  
pp. 1943-1957
Author(s):  
Simona Merola ◽  
Luca Marchitto ◽  
Cinzia Tornatore ◽  
Gerardo Valentino
Keyword(s):  
Diesel Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Injection Pressure ◽  
Common Rail ◽  
Pilot Injection ◽  
Soot Emission ◽  
Compression Ignition Engine ◽  
Working Cycle ◽  
Main Injection

Combustion process was studied from the injection until the late combustion phase in an high swirl optically accessible combustion bowl connected to a single cylinder 2-stroke high pressure common rail compression ignition engine. Commercial diesel and blends of diesel and n-butanol (20%: BU20 and 40%: BU40) were used for the experiments. A pilot plus main injection strategy was investigated fixing the injection pressure and fuel mass injected per stroke. Two main injection timings and different pilot-main dwell times were explored achieving for any strategy a mixing controlled combustion. Advancing the main injection start, an increase in net engine working cycle (>40%) together with a strong smoke number decrease (>80%) and NOx concentration increase (@50%) were measured for all pilot injection timings. Compared to diesel fuel, butanol induced a decrease in soot emission and an increase in net engine working area when butanol ratio increased in the blend. A noticeable increase in NOx was detected at the exhaust for BU40 with a slight effect of the dwell-time. Spectroscopic investigations confirmed the delayed auto-ignition (~60 ms) of the pilot injection for BU40 compared to diesel. The spectral features for the different fuels were comparable at the start of combustion process, but they evolved in different ways. Broadband signal caused by soot emission, was lower for BU40 than diesel. Different balance of the bands at 309 and 282 nm, due to different OH transitions, were detected between the two fuels. The ratio of these intensities was used to follow flame temperature evolution.

scholarly journals Pyrolysis-GC/MS Analysis of Fast Growing Wood Macaranga Species

2021 ◽  
Vol 6 (1) ◽  
pp. 141-158
Author(s):  
R.R. Dirgarini J.N. Subagyono ◽  
Ying Qi ◽  
Alan L. Chaffee ◽  
Rudianto Amirta ◽  
Marc Marshall
Keyword(s):  
Thermal Degradation ◽  
Pyrolysis Temperature ◽  
Woody Biomass ◽  
Biofuel Production ◽  
Flash Pyrolysis ◽  
Fast Growing ◽  
Ms Analysis ◽  
Bio Oil ◽  
Different Temperatures ◽  
High Yields

Py-GC/MS analysis of six different species of fast growing Macaranga wood has been studied. Flash pyrolysis was conducted at different temperatures (250-850 oC) under a flow of helium followed by GC/MS analysis of the products. The total pyrolysis yields of the six different species of Macaranga were mostly between 40 and 90% within the range of pyrolysis temperature applied.  Pyrolysis of the woody biomass produced compounds which are mostly derived from thermal degradation or volatilization of lignin and cellulose/hemicellulose, the original major constituents of the biomass. The Py-GC/MS technique indicated that M. gigantea was the most potential species for biofuel production and the optimum pyrolysis temperature to produce high yields of bio-oil was 450 oC.

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