Research Repository :: Browsing by Author "Mkilaha, Iddi"

Browsing by Author "Mkilaha, Iddi"

Now showing 1 - 20 of 20

Analysis of Nox Reduction in Diesel Engines By Air Injection Using Stochastic Modelling
(2009-07) Mkilaha, Iddi; John, G. R.
Combustion phenomena have been found to be dependent on the turbulence of the air/gas and fuel in the cylinder. By enhancing turbulent mixing of fuel in the combustion chamber it is possible to improve combustion process. Based on the stochastic nature of turbulence of combustion processes as occurring in an IDI internal combustion engine, a model was developed based on these principles when compressed air was injected into the engine. The air injection was carried out in order to control the emission of NO x and soot simultaneously. In the present model, the mechanism of NO x formation is modeled using the thermal NO x principles while the soot emission is modeled using the global combustion model, which considered combustion as heat addition. Obtained results show close agreement with the experimental ones. The Zeldovich model used has been found model closely IDI engine processes also for the case of air injection as is case of a normal engine. This is due to the microscopic treatment of the mixing process, which involved over-simplification of HC combustion chemistry. It is shown that although there is no substantial temperature drop when compressed air was injected into the chamber, at microscopic scales, the mixing process that occur lead to local temperature drop. It is these local areas of temperature quenching that enhance the suppression of the formation of NO x . At high loads, however, particulate and HC are increased due to the enrichment of fuel in the local areas where the temperatures have substantially been reduced
Analysis of Tanzanian Energy Demand Using Artificial Neural Network and Multiple Linear Regression
(2014-12) Kichonge, Baraka; Tesha, Thomas; Mkilaha, Iddi; John, Geoffrey
Analysis of energy demand is of a vital concern to energy systems analysts and planners in any nation. This paper present artificial neural network-multilayer perceptron (ANNMLP) and multiple linear regression (MLR) techniques for the analysis of energy demand in Tanzania. The techniques were employed to analyze the influence of economic, energy and environment indicators models in predicting the energy demand in Tanzania. Statistical performance indices were used to evaluate the prediction ability of economic, energy and environment indicators models using ANN-MLP and MLR techniques. Predicted responses values of ANN-MLP and MLR techniques were then compared to determine their closeness with actual data values for determining the best performing technique. The results from ANN-MLP and MLR techniques showed the best model for predicting the energy demand in Tanzania were from energy indicators as opposed to economic and environmental indicators. The ANN-MLP prediction values had a correlation coefficient (CC) of 0.9995 and mean absolute percentage error (MAPE) of 0.67% outperforming the MLR technique whose CC and MAPE values were 0.9993 and 0.83% respectively. ANN-MLP technique graphical presentation of actual against predicted values showed close relationship between actual and predicted values as opposed to the MLR technique whose predicted values deviated much from actual values. Analysis of results from both techniques conclude that ANN-MLP outperform MLR technique in predicting energy demand in Tanzania.
Carbon Monoxide Exposure during Cooking in Households: A Case of Dar es Salaam City, Tanzania
(David Publishing, 2013) Legonda, Isack A.; Marsh, Richard; Mkilaha, Iddi; Griffith, Anthony
Exposure to CO (carbon monoxide) during cooking in households using LPG (liquefied petroleum gas), natural gas and charcoal as fuels has been conducted. The study aimed at assessing the indoor air quality in order to address potential hazards associated with CO. Carbon monoxide concentrations and flame temperature were measured at an interval of 1 min for 1 h using CO and thermometer data loggers respectively. While the CO concentration from LPG and natural gas were found below 26 ppm for 1 h, as recommended by WHO (World Health Organization) standards, the average CO concentration from charcoal exceeded the standard limit. In addition closing the kitchen door during cooking increased the CO concentration from 26-295 ppm to 92-597 ppm. According to WHO, the observed CO concentrations from charcoal stove highlights questionable life support atmosphere. It can therefore be suggested that switching to LPG or natural gas from charcoal will reduce CO exposure to persons during cooking.
Comparative Study of Lead and Cadmium Compounds Capture by Sorbents
(2002-04) Yao, Hong; Saito, Noboru; Mkilaha, Iddi; Naruse, Ichiro
Trace metal compounds, which are emitted from combustion systems such as waste incinerators, coal combustors, and so forth, enrich in fine particulates, usually formed during various stages of combustion. Owing to the difficulties of capturing fine particulates by conventional particulate dust collection systems, these are exhausted in the atmosphere. Fundamentals of the emission and control of trace metal compounds of lead and cadmium were studied at relatively low temperature (1073-1273 K), using a thermobalance. In order to capture these trace metal compounds, seven types of sorbent, namely alumina, silica, kaolin, limestone, scallop, zeolite and apatite, were used. As a result, the natural aluminosilicate materials like kaolin and zeolite were found to be effective in capturing lead and cadmium chemically. Although the presence of HCl decreases capture efficiencies, the products didn't react with HCl. The types of kaolin had a little influence on the capture efficiency and processes in general. On the other hand, the calcium-based sorbents like limestone, scallop and apatite, could capture both the trace metals and chlorine. On the presence of HCl, the capture efficiencies of these sorbents decreased sharply. Both alumina and silica have low ability to capture trace metal compounds. Moreover, in reducing atmosphere, all sorbents showed low capture abilities since the products were reduced.
Experimental study on carbon monoxide exposure during cooking in households: A case of Dar es Salaam, Tanzania
(2012-12) Legonda, Issack A.; Marsh, Richard; Idd; Mkilaha, Iddi; Graffins, A.J.
Exposure to CO (carbon monoxide) during cooking in households using LPG (liquefied petroleum gas), natural gas and charcoal as fuels has been conducted. The study aimed at assessing the indoor air quality in order to address potential hazards associated with CO. Carbon monoxide concentrations and flame temperature were measured at an interval of 1 min for 1 h using CO and thermometer data loggers respectively. While the CO concentration from LPG and natural gas were found below 26 ppm for 1 h, as recommended by WHO (World Health Organization) standards, the average CO concentration from charcoal exceeded the standard limit. In addition closing the kitchen door during cooking increased the CO concentration from 26-295 ppm to 92-597 ppm. According to WHO, the observed CO concentrations from charcoal stove highlights questionable life support atmosphere. It can therefore be suggested that switching to LPG or natural gas from charcoal will reduce CO exposure to persons during cooking.
Formation Characteristics of Fine Particulates with Na Compounds during Coal Combustion
(2003-10) Takuwa, Tsuyoshi; Mkilaha, Iddi; Naruse, Ichiro
Some metal compounds in coal vaporize and form fumes during the combustion. The fumes are usually exhausted through the flue gas. For coal-fired combined power generation systems such as pressurized fluidized bed combustion (PFBC), hot metallic vapors may contact with the surfaces of gas-turbine blades. Since this contact of the hot vapors with the surface has a corrosive effect, it is necessary to control the formation of those fumes, which contain alkali metal compounds. In this paper, the evolution behavior of alkali metal compounds, especially sodium compounds, has been studied, using an electrically heated drop tube furnace with a low-pressure impactor. The main objective in this study is to elucidate the conditions and the possible mechanisms to form alkali metal compounds in particulate matter during combustion. Two types of coal with different sodium contents were tested, where the coal conversion characteristics were established. Furthermore, the evolution and inclusion of sodium compounds into the sub-micron particles were studied in relation to the particle size distribution and sodium fraction distribution in the collected particulates. The study proved that the evolution and inclusion of sodium on sub-micron particles depended on the functions of the coal type. The reaction-controlled mechanism and heterogeneous condensation via chemical reactions during the combustion much more influenced the inclusion of sodium in sub-micron particles. At the coarse particles of above about 0.5 μm, the reaction that formed the particles was mainly via gas film diffusion surrounding the particle.
Fundamentals on Vaporization Behavior of Trace Metal Compounds at Different Atmospheres and Temperatures.
(2001-12) Yao, Hong; Mkilaha, Iddi; Naruse, Ichiro
Trace metals are usually inevitably contained in wastes, coals and so forth. When the wastes and/or coals are burnt, pollutants like NOx, SOx, soot, particulates, dioxins and heavy metal compounds are emitted from the furnaces. Some of the heavy trace metal compounds condense on the particle surface and/or form fine particulates during the combustion/incineration processes. Owing to the difficulties in capturing those fine particulates by means of conventional dust collection systems, those particulates tend to be exhausted into the atmosphere. In this study, fundamental behavior of the vaporization of Pb, Cd and Cr compounds was studied at relatively low temperature. In this experiment the effects of temperature and reaction atmosphere on the vaporization behavior of Pb, Cd and Cr compounds were studied using a thermobalance. The chemical thermoequilibrium calculation for each compound was also carried out in order to validate the experimental results obtained. As a result, the vaporization behavior of the metal compounds appears dependent on their respective melting points. Most of chlorides were easily vaporized at relatively low temperatures. This suggests that the presence of HCl enhances the vaporization of metal compounds, while co-existence of SO2 shows inhibition of the vaporization tendencies of Pb and Cd compounds. All of the Cd compounds vaporized in the reducing conditions. The results of chemical thermoequilibrium calculation agreed closely with the experimental results obtained.
Influence of Gas Type and Injection System on Simultanous Reduction of Soot and NOx in IDI Diesel Engine.
(1995-09) Mkilaha, Iddi; Kawai, Daizaburo; Inoue, Mitsunori; Naruse, Ichiro; Ohtake, Kazutomo
Modification has been made to one of the prechambers of a 4-cylinder. IDI diesel engine used to study the combustion process, for the purpose of reducing emissions. With the provisions for optical assessment o the combustion process in the prechamber, the effect of high-pressure gas injection into the prechamber during injection has been carried out. Results of this work indicate that high-pressure gas injection during combustion can affect simultaneous soot and NOx reduction with a reasonably low amount of emission of other diesel engine pollutants. An optimum chamber type is suggested based on analysis of the effect of air, argon and nitrogen injection.
Mechanisms of fine particulates formation with alkali metal compounds during coal combustion
(2006-02) Takuwa, Tsuyoshi; Mkilaha, Iddi; Naruse, Ichiro
Two types of coals with different sodium (Na) and potassium (K) concentrations were burned in an electrically heated drop tube furnace, to study the formation of particulates in association to alkali metal compounds from the coals. The particulates formed from these coals during combustion were separated by a low pressure impactor (LPI). The particulates collected in each stage of the LPI were analyzed, using an atomic adsorption spectrometer (AAS). The results obtained show that ash particles have bimodal particle size distribution for both coal types. This tendency could be due to the difference of the inherent minerals in raw coals. It was further observed that Na and K were enriched in the fine particulates for both types of coal. There was a dependence of the Na enrichment on the fine particles on concentration of excluded mineral in the raw coals. This work, therefore, showed that the appearance of alkali metal in the ash particles related to the nature of Na and K concentrations in raw coals.
Modeling Future Energy Demand for Tanzania
(2013-12) Kichonge, Baraka; John, Geoffrey; Mkilaha, Iddi; Hameer, Sameer
This paper present modelling of long-term energy demand forecast in the main economic sectors of Tanzania. The forecast of energy demand for all economic sectors is analyzed by using the Model for Analysis of Energy Demand (MAED) for a study period from 2010-2040. In the study three scenarios namely business as usual (BAU), low economic consumption (LEC) and high economic consumption scenario (HEC) were formulated to simulate possible future long-term energy demand based on socio-economic and technological development with the base year of 2010. Results from all scenario suggests an increased energy demand in consuming sectors with biomass being a dominant energy form in service and household sectors in a study period. Predicted energy demand is projected to increase at a growth rate of 4.1% and reach 74 MTOE in 2040 under BAU scenario. The growth rates for LEC and HEC are projected at 3.5% and 5.1% reaching 62 MTOE and 91 MTOE in 2040 respectively. Electricity demand increases at a rate of 8.5% to reach 4236 kTOE in 2040 under BAU scenario while electricity demand under LEC and HEC increases to 3693 kTOE and 5534 kTOE in 2040 respectively. Sectrorial predicted demand results under both scenarios determines high demand of biomass for service and household sectors with decreasing demand of biomass in industry sector. Transport sectors predicted energy demand pattern suggests an increased demand in passenger transport than freight transport in both scenarios. Final energy demand per capita in both scenario show an increased trend with lower growth in LEC scenario while there is a decrease in energy intensity throughout study period.
Modelling energy supply options for electricity generations in Tanzania
(2015-07) Kichonge, Baraka; John, Geoffrey; Mkilaha, Iddi
The current study applies an energy-system model to explore energy supply options in meeting Tanzania's electricity demands projection from 2010 to 2040. Three economic scenarios namely; business as usual (BAU), low economic consumption scenario (LEC) and high economic growth scenario (HEC) were developed for modelling purposes. Moreover, the study develops dry weather scenario to explore how the country's electricity system would behave under dry weather conditions. The model results suggests: If projected final electricity demand increases as anticipated in BAU, LEC and HEC scenarios, the total installed capacity will expand at 9.05%, 8.46% and 9.8% respectively from the base value of 804.2MW. Correspondingly, the model results depict dominance of hydro, coal, natural gas and geothermal as least-cost energy supply options for electricity generation in all scenarios. The alternative dry weather scenario formulated to study electricity system behaviour under uncertain weather conditions suggested a shift of energy supply option to coal and natural gas (NG) dominance replacinghydro energy. The least cost optimization results further depict an insignificant contribution of renewable energy technologies in terms of solar thermal, wind and solar PV into the total generation shares. With that regard, the renewable energy penetration policy option (REPP), as an alternative scenario suggests the importance of policy options that favour renewable energy technologies inclusion in electricity generation. Sensitivity analysis on the discount rate to approximate theinfluence of discount rate on the future pattern of electricity generation capacity demonstrated that lower values favourwind and coal fired power plants, while higher values favour the NG technologies. Finally, the modelling results conclude the self-sufficiency of the country in generating future electricity using its own energy resources.
Prediction of Tanzanian Energy Demand using Support Vector Machine for Regression (SVR)
(2015-01) Kichonge, Baraka; John, Geoffrey; Tesha, Thomas; Mkilaha, Iddi
This study discusses the influences of economic, energy and environment indicators in the prediction of energy demand for Tanzania applying support vector machine for regression (SVR). Economic, energy and environment indicators were applied to formulate models based on time series data. The experimental results showed the supremacy of the polynomial-SVR kernel function and the energy indicators model in providing the transformation, which achieved more accurate prediction values. The energy indicators model had a correlation coefficient (CC) of 0.999 as equated to 0.9975 and 0.9952 with PUKF-SVR kernels for economic and environment indicators model. The energy indicators model closeness of predicted values as compared to actual values was the best as compared to economic and environment indicators models. Furthermore, root mean squared error (RMSE), mean absolute error (MAE), root relative squared error (RRSE) and relative absolute error (RAE) of energy indicators model were the lowest. Long-run sustainable development of the energy sector can be achieved with the use of SVR-algorithm as prediction tool of future energy demand.
Pyrolysis Oil Combustion in a Horizontal Box Furnace with an Externally Mixed Nozzle
(2016-04) Lujaji, Frank C.; Boateng, Akwasi A.; Schaffer, Mark A.; Mullen, Charles A.; Mkilaha, Iddi; Mtui, Peter L.
Combustion characteristics of neat biomass fast-pyrolysis oil were studied in a horizontal combustion chamber with a rectangular cross-section. An air-assisted externally mixed nozzle known to successfully atomize heavy fuel oils was installed in a modified 100 kW (350"000 BTU/h nominal capacity) burner to explore full utility for pyrolysis oil (bio-oil) combustion in a furnace. Combustion experiments were conducted at air/fuel equivalence ratios of 0.46, 0.53, and 0.68 (116, 88, and 47% excess air, respectively) and compared to diesel fuel flames (control) at the two higher air/fuel equivalence ratios. In these experiments, the fuel flow rate was maintained at a constant energy input (equivalent of 24 kWth). The results revealed that, while the externally mixed nozzle could effectively atomize and ensure stable combustion of neat bio-oil at the set heat rate, this comes with a penalty associated with a lower peak flame temperature and, hence, heat flux. The formation of carbon monoxide (CO) decreases with an increasing air/fuel equivalence ratio for bio-oil combustion. The levels of carbon dioxide (CO2) and nitrogen oxides (NOx) increase with an increasing air/fuel equivalence ratio for bio-oil combustion and were slightly higher than that generated by diesel. Hydrocarbon emissions do not follow any defined trend with an increasing air/fuel equivalence ratio for bio-oil, as typically observed for diesel fuels as a result of the oxygenated nature of bio-oil.
Reduction of pollutants from diesel exhaust by high pressure gas injection
(1997-06) Kawai, Daizaburo; Mkilaha, Iddi; Osawa, Takuya; Naruse, Ichiro; Ohtake, Kazutomo
In order to reduce the pollutants from diesel exhaust, high-pressure gas was injected during combustion into a modified pre-chamber of an IDI diesel engine at a varied load and gas injection timing. The result shows that high-pressure gas injection can reduce the particulates and NOx simultaneously, with little influence on the engine performance. The combustion process in the pre-chamber was visualized by means of an ultra high-speed video system and image analysis of the pictures obtained. The results of the visualization show that by injecting gas, the flame is first quenched, followed by the reduction of NOx in the pre-chamber by hydrocarbon. Although high-pressure gas injection could have caused a substantial increase in HC as a result of temperature quenching, this seems to be controlled by the consumed portion of HC during the recycling of NOx. Chemical analysis of polycyclic aromatics compounds was carried out for the purpose of establishing its variations with gas injection. It was established that gas injection not only reduces PM by oxidation of solid carbon, but also the PAH component.
Screening of sorbents and capture of lead and cadmium compounds during sewage sludge combustion
(2004-04) Yao, Hong; Mkilaha, Iddi; Naruse, Ichiro
Current understanding has shown that aluminosilicate- and calcium-based sorbents could be applied to control trace metals emission from combustion and incineration processes. However, the use of industrial commercial sorbents is not always appropriate. The present study dwells on the use of natural and waste materials as sorbents to capture lead and cadmium compounds during combustion. The main task is to optimize the use of those materials by screening them, using a thermobalance. Then, the determined optimum sorbent was tested on an electrically heated drop tube furnace, burning sewage sludge at temperatures ranging from 1073 to 1223 K. The results showed that some of aluminosilicate-based sorbent were more effective than calcium-based sorbents. Kaolin was found to be a relatively effective sorbent for Pb and Cd capturing. The results further showed that the capture ability depended on chemical compositions and specific surface area of the sorbents. Presence of HCl caused a little decrease in the capture ability, using aluminosilicate-based sorbents, while significant effect on the capture processes was noted when calcium-based sorbents were used. Furthermore, when kaolin was added into the sewage sludge, kaolin was an appropriate sorbent to control lead and cadmium emissions. Temperature increase enhances the capture ability under our experimental conditions. Kaolin addition played a role for low leachability of the trace metals.
Simultaneous reduction of particulate matter and NOx in a diesel engine by compressed gas injection: Macroscopic study at residual load
(1997-02) Mkilaha, Iddi; Inoue, M; Kawai, Daizaburo; Naruse, Ichiro; Ohtake, Kazutomo
A modified pre-chamber of an indirect injection (IDI) diesel engine was used to elucidate the influence on emissions of compressed air injection into the pre-chamber during combustion. The test parameters were air injection timing and arrangements of gas injection. This paper presents the experimental results for two types of injection arrangements; I- and Y-type. The I-type is arranged such that the gas injection jet and fuel injection nozzle are in opposite directions, while the Y-type is such that it forms a ‘Y’ shape with the nozzle and the passageway. Results obtained reveal that the Y-type arrangement is superior in combustion characteristics and emissions reduction to the I-type. A remarkable reduction in both particulate matter (PM) and NOx is realized at air injection timings during 35° and 65° after top dead centre (ATDC). The reduction mechanism can be explained as due to the induced turbulence which improves mixing and heat transfer. The effect of the modifications on the performance of the engine was evaluated based on the fuel economy and efficiency. This evaluation has shown that the test cylinder approximates closely to the normal cylinder of the original engine
Sorbent control of trace metals in sewage sludge combustion and incineration
(2013-04) Naruse, Ichiro; Yao, Hong; Mkilaha, Iddi
Coal and wastes combustion have become an important issue not only in terms of energy generation but also environmental conservation. The need for alternative fuels and wastes management has made the two energy sources of importance. However, the utilization of the two is faced with problems of impurity trace metals in the fuel. These metals usually speciate during combustion or incineration leading to generation of fumes and subsequently particles. This paper reports on the study aimed at understanding the speciation of trace metals and their emission from combustion systems as particulates. Experiments carried out using a down-flow furnace and theoretical study carried out using lead, chromium and cadmium as basic metals had shown that their speciation and subsequent emission is controlled by both chemical composition and physical properties of the fuel. The physical and chemical and physical properties of the fuel and their respective compounds and the operating conditions of the incineration and combustion system control the enrichment of the particles with trace metals.
Spray Atomization of Bio-Oil/Ethanol Blends with Externally Mixed Nozzles
(2015-09) Lujaji, Frank; Boateng, Akwasi A.; Schaffer, Mark A .; Mtui, Peter L.; Mkilaha, Iddi
Experiments were conducted to investigate the properties of sprays of pyrolysis oil (bio-oil) blends with ethanol using an air assisted atomization nozzle operated without combustion. This was done in order to explore the potential for pyrolysis oil combustion in industrial and residential furnaces. The liquid samples investigated were bio-oil blends with ethanol (EtOH), neat ethanol and diesel. The bio-oil:EtOH blends were prepared in concentrations of 20:80 and 40:60vol%. Twin-fluid externally mixed nozzles SU2, SU4, and SU5 with liquid orifice areas of 0.40, 1.82 and 5.07mm2, respectively, were used in the spray experiments. The liquid and atomizing air flow rates as well as temperature were controlled to maintain constant liquid flow rates (cc/s) equivalent to 30 and 50kW energy input. Images of atomized spray droplets were measured to determine their size and velocity. Results show that it is possible to spray bio-oil/ethanol mixtures containing up to 40% bio-oil that has a low water content (12.60%). High viscosity and a tendency to coagulate were the main drawbacks; however, the 20:80 bio-oil:EtOH blend and neat ethanol in all three nozzles exhibited spray characteristics similar to that of diesel over atomization air flow rates of 15-30SLPM.
Thermodynamic analysis of the role of chlorine and sulfur environments during combustion and incineration processes
(2002-09) Mkilaha, Iddi; Yao, Hong; Naruse, Ichiro
In order to control the emission of trace metals from combustion and incineration systems, sorbents and filters are sometimes used. However, the effectiveness of these methods is greatly affected by the volatility of the metals and the way in which they speciate during combustion, and afterwards during condensation, and physical or chemical sorption. Although there has been a lot of research into the mechanisms by which trace metals speciate and subsequently appear in submicron particles, the details of these mechanisms are not yet thoroughly understood. In this study, a chemical equilibrium approach was used to qualitatively determine the speciation of lead, cadmium, and chromium in Cl and S environments. The reaction conditions of sorbents were also tested numerically in order to understand the reaction behavior of metals with sorbents. This article reports the influence of different concentrations of Cl and SO2 on Pb, Cd, and Cr speciation, as representatives of other trace elements. The partitioning behavior of metals during combustion was also examined for Cl and S. The results obtained indicate that most metals exist in the vapor phase, even at low temperatures, when chlorine is present. However, the addition of SO2 enhances the formation of the condensed phase, except at extremely high temperatures. This observation was not significant for Cd or Cr. The higher the concentration of Cl the higher the retention of trace metals in the vapor phase, even at low temperatures. Results from comparisons of the reactivities of mixed metals with Cl indicate that the presence of Fe limits the reactivity of most trace metals with Cl except at higher concentrations. In the presence of Fe, alkali metals are the first to react with Cl. If Fe is not present, most trace metals react with Cl, and the activity increases with higher concentrations. On the other hand, the partitioning characteristics of S show that its presence generally means that metals remain in the condensed phase. Sulfur is more reactive with alkali metals than with other trace metals.
Trace-metal speciation during sludge combustion and incineration
(2002-10) Mkilaha, Iddi; Yao, Hong; Naruse, Ichiro
Municipal waste combustion has been opted as a method for reducing the size of the volume, and consequently, for reducing the necessary requirement of areas for direct disposal. However, the emission of the conventional gaseous pollutants are not the only problem; traces of metal fumes emanate from the metallic compounds that are in the wastes. Efforts to control these metal fumes have not been so successful because of the complicated mechanisms of the metallic compounds during combustion. Failure of the conventional systems to trap the trace elements is due to their appearance with the submicron particles from the combustion and incineration systems. In this work, a thermochemical equilibrium approach is employed to study the combustion and gasification behavior of trace metals with a case of lead, cadmium, and chromium during the incineration of sewage sludge. In this work, sulfur and chlorine have been found to play a key role in the speciation of the trace metals. However, these elements are only active when oxygen is present. A test on alkali metals mixed with trace metals showed that at low concentrations of S and Cl, the alkali metals react first with these elements before other metals. Chlorine assists in retaining most of the trace metals in the vapor phase while sulfur keeps them in the condensed form. The presence of iron, as is the case with most sorbents, hinders the reaction of Cl with the metals, thus suppressing the formation of volatile compounds.

Browsing by Author "Mkilaha, Iddi"

Results Per Page

Sort Options