Papers by Dr. Khamphe Phoungthong
Effect Of Equivalent Ratio (ER) On the Flow and Combustion Characteristics in A Typical Underground Coal Gasification (UCG) Cavity, 2021
Underground Coal Gasification (UCG) is one of the most favourable clean coal technology options f... more Underground Coal Gasification (UCG) is one of the most favourable clean coal technology options from geological-engineering-environmental viewpoint (less polluting and high efficiency) for extracting energy from coal without excavating or burning it on the surface. UCG process requires injecting oxidizing agent (O2 or air with steam) as raw material, into the buried coal seam, at an effective ratio which regulates the performance of gasification. This study aims to evaluate the influence of equivalent ratio (ER) on the flow and combustion characteristics in a typical half tear-drop shape of UCG cavity which is generally formed during the UCG process. A flow modelling software, Ansys FLUENT is used to construct a 3-D Computational Fluid Dynamics (CFD) model and to solve flow hydrodynamics in the cavity. The boundary conditions are-(i) a mass-flow-inlet passing oxidizer (in this case, air) into the cavity, (ii) a fuel-inlet where the coal volatiles are originated and (iii) a pressure-outlet for flowing the product synthetic gas (syngas) out of the cavity. A steady-state simulation has been run using k-ε turbulence model. The mass flow rate of air varied according to an equivalent ratio (ER) of 0.16, 0.33, 0.49 and 0.82, while the fuel flow rate was fixed. The optimal condition of ER has been identified through observing flow and combustion characteristics, which looked apparently stable at ER 0.33. In general, the flow circulation mainly takes place around the ash-rubble pile. A high temperature zone is found at the air-releasing point of the injection pipe into the ash-rubble pile. This study could practically be useful to identify one of the vital controlling factors of gasification performance (i.e., ER impact on product gas flow characteristics) which might become a cost-effective solution in advance of commencement of any physical operation.
PM, PAHs and BaPeq emissions of IDI-turbo diesel engine fueled by PB0, PB40 and PB50 during long-... more PM, PAHs and BaPeq emissions of IDI-turbo diesel engine fueled by PB0, PB40 and PB50 during long-term usage were investigated.The total emissions of PB0, PB40 and PB50 corresponded with the running times of the engine.The concentration of 4–6 ring PAHs increased when the running time of the engine was increased for all three fuels.The IDI-turbo diesel engine is not appropriate and enable for long-term usage fueled with PB50.We examined particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and carcinogenic potencies of benzo[a]pyrene equivalent (BaPeq) emissions from an indirect injection (IDI-turbo) diesel engine fueled by commercial diesel (PB0) and palm oil blends with portions of 40 and 50 vol.% (PB40 and PB50). The engine was in operation over long-term test cycles. A four-stage cascade impactor air sampler was used to collect particles emitted from the engine. The PM and PAHs were predominantly fine particles (<1 μm) and show an accumulation mode. The total emissions of the IDI-turbo diesel engine increased when the operation times were increased. The mass fractions of 2–3 rings PAHs using PB0, PB40, and PB50 contributed 35.5%–40.6%, 44.7%–50.2%, and 45.9%–51.4%, respectively; for PB0 2–3 ring PAHs contributed less than palm oil blends. Using PB40 and PB50 caused a higher emission of lower molecular weight PAHs than PB0. However, the mass fractions showed that the concentration of 4–6 ring PAHs increased when the running time of the engine was increased for all three fuels. The results in this study showed that significant emissions of PM, PAHs, and BaPeq were reduced as the fraction ratio of palm oil was increased because palm oil blends have a high amount of oxygen, which enhances combustion compared to PB0. Although PM, PAHs, and BaPeq emissions of PB50 were less than those of PB0 and PB40, PB50 is not an appropriate fuel for the long-term running of this engine.
Municipal solid waste incinerator bottom ash (MSWIBA) has long been regarded as an alternative
bu... more Municipal solid waste incinerator bottom ash (MSWIBA) has long been regarded as an alternative
building material in the construction industry. However, the pollutants contained in the bottom ash
could potentially leach out and contaminate the local environment, which presents an obstacle to the
reuse of the materials. To evaluate the environmental feasibility of using MSWIBA as a recycled material
in construction, the leaching derived ecotoxicity was assessed. The leaching behavior of MSWIBA under
various conditions, including the extractant type, leaching time, liquid-to-solid (L/S) ratio, and leachate
pH were investigated, and the phytotoxicity of these leachates on wheat (Triticum aestivum L.) seed
germination was determined. Moreover, the correlation between the germination index and the concentrations
of various chemical constituents in the MSWIBA leachates was assessed using multivariate
statistics with principal component analysis and Pearson's correlation analysis. It was found that, heavy
metal concentrations in the leachate were pH and L/S ratio dependent, but were less affected by leaching
time. Heavy metals were the main pollutants present in wheat seeds. Heavy metals (especially Ba, Cr, Cu
and Pb) had a substantial inhibitory effect on wheat seed germination and root elongation. To safely use
MSWIBA in construction, the potential risk and ecotoxicity of leached materials must be addressed.
The leaching behavior of Ca-based compounds commonly in MSWI residues was studied.pH is the cruci... more The leaching behavior of Ca-based compounds commonly in MSWI residues was studied.pH is the crucial factor for calcium leaching process.CaCO3 was the most sensitive to leaching temperature and Ca3(PO4)2 was the least.Ca leaching of MSWIBA and SAPCR attributed to CaCO3 and Ca3(PO4)2 respectively.Potential clogging ability of MSWI residues leachate in open air was calculated.Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO3 and CaSiO3 began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca3(PO4)2 leached at pH < 12. CaSO4 could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO3 > Ca3(PO4)2 > CaCO3. The calcium leaching from the MSWIBA and SAPCR separately started from pH < 7 and pH < 12, resulting from CaCO3 and Ca3(PO4)2 leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the theoretical basis for the risk assessment pertaining to LCS clogging in landfills.
Abstract：In an attempt to predict landfill anaerobic degradation parameters (L 0 , methane genera... more Abstract：In an attempt to predict landfill anaerobic degradation parameters (L 0 , methane generation potential, k, decay rate and CSF, carbon sequestration factor) more conveniently, the linkage between biochemical characteristics of degradable solid wastes and anaerobic degradation parameters was established. The biochemical characteristics of twenty-eight kinds of degradable solid wastes including C, H, N, polysaccharide, protein, lipid, hemicellulose, cellulose, and lignin, were measured. Four kinds of biochemical characteristics including polysaccharide, protein, lipid, and lignin were determined to substitute for the original nine kinds of biochemical characteristics through factor analysis.
Journal of Environmental Sciences
Conference Presentations by Dr. Khamphe Phoungthong
20th Heat and Mass Transfer in Thermal Equipment and Process , 2021
Underground Coal Gasification (UCG) is one of the most promising options for the future use of co... more Underground Coal Gasification (UCG) is one of the most promising options for the future use of coal from geological-engineering perspective aligned with environmental considerations, being the preferable clean coal technology (less polluting and high efficiency). The process requires injecting oxidant (O 2 or air with steam) into the underground coal seam at an effective ratio which maneuvers the gasification performance. The aim of this work is to study the flow and combustion characteristics in a typical UCG cavity at a constant equivalent ratio (ER). A 3-D computational fluid dynamics (CFD) model has been conducted using ANSYS (Fluent), in a conventional cavity geometry which is formed during the process of UCG. The cavity geometry is considered as a half tear-drop shape having the following boundary conditions-(i) a mass-flow-inlet passing oxidant (air) into the cavity, (ii) a fuel-inlet where the coal volatiles are originated and (iii) a pressure-outlet for product Syngas. The cell zone conditions are set to a porous fluid domain of coal-wall bounded ash-rubble pile containing the coal volatiles. This is a steady-state, k-epsilon turbulence model. The mass flow rate of fuel has been fixed while the air flow rate is measured according to an equivalent ratio (ER) of 0.33. The results show that the circulation flow takes place around the ash-rubble pile. The peak temperature is encountered at the bottom of the injection pipe where air is released form the pipe into the ash-rubble pile, as such that the region of high temperature lies within the area.
Sriwijaya International Conference on Engineering and Technology (SICETO), 2021
Underground Coal Gasification (UCG) bears great potential to combine several steps from technoenv... more Underground Coal Gasification (UCG) bears great potential to combine several steps from technoenvironmentally critical mining process to the traditional cleaning, preparation and burning/combustion into a single operation which would be acceptable from geological-engineering-environmental viewpoint. Thus this could be recognized as one of the most favorable clean coal technology options (less polluting and high efficiency). UCG could harness energy from versatile and apparently unexploitable coal resources which are otherwise thought unmineable. Yet after that, there are several key factors which govern a successful UCG venture in any operable site. This study explores the desired site characteristics of the coalfields preferred for selecting best candidate for UCG exercise. The study deduces that prerequisites of UCG application are predominantly site selection factors (depth and thickness of coal seam, coal rank, ash content, absence of major discontinuity, distance from any significant aquifer, etc.) and also the operational efficiency to maneuver the process undertaken in a subject coalfield. This work can facilitate the approaches for siting the UCG in a coalfield.
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Papers by Dr. Khamphe Phoungthong
building material in the construction industry. However, the pollutants contained in the bottom ash
could potentially leach out and contaminate the local environment, which presents an obstacle to the
reuse of the materials. To evaluate the environmental feasibility of using MSWIBA as a recycled material
in construction, the leaching derived ecotoxicity was assessed. The leaching behavior of MSWIBA under
various conditions, including the extractant type, leaching time, liquid-to-solid (L/S) ratio, and leachate
pH were investigated, and the phytotoxicity of these leachates on wheat (Triticum aestivum L.) seed
germination was determined. Moreover, the correlation between the germination index and the concentrations
of various chemical constituents in the MSWIBA leachates was assessed using multivariate
statistics with principal component analysis and Pearson's correlation analysis. It was found that, heavy
metal concentrations in the leachate were pH and L/S ratio dependent, but were less affected by leaching
time. Heavy metals were the main pollutants present in wheat seeds. Heavy metals (especially Ba, Cr, Cu
and Pb) had a substantial inhibitory effect on wheat seed germination and root elongation. To safely use
MSWIBA in construction, the potential risk and ecotoxicity of leached materials must be addressed.
Conference Presentations by Dr. Khamphe Phoungthong
building material in the construction industry. However, the pollutants contained in the bottom ash
could potentially leach out and contaminate the local environment, which presents an obstacle to the
reuse of the materials. To evaluate the environmental feasibility of using MSWIBA as a recycled material
in construction, the leaching derived ecotoxicity was assessed. The leaching behavior of MSWIBA under
various conditions, including the extractant type, leaching time, liquid-to-solid (L/S) ratio, and leachate
pH were investigated, and the phytotoxicity of these leachates on wheat (Triticum aestivum L.) seed
germination was determined. Moreover, the correlation between the germination index and the concentrations
of various chemical constituents in the MSWIBA leachates was assessed using multivariate
statistics with principal component analysis and Pearson's correlation analysis. It was found that, heavy
metal concentrations in the leachate were pH and L/S ratio dependent, but were less affected by leaching
time. Heavy metals were the main pollutants present in wheat seeds. Heavy metals (especially Ba, Cr, Cu
and Pb) had a substantial inhibitory effect on wheat seed germination and root elongation. To safely use
MSWIBA in construction, the potential risk and ecotoxicity of leached materials must be addressed.