Further Rise In Temperature Research Articles

Preparation and characterization of indium chalcogenide thin films: A material for phase change memory

The versatile resistive switching behavior of metal chalcogenide thin films is highly desired for the fabrication of phase change memory (PCM) - electronic devices. The In2(Te1-xSex)3 thin films might be one of the prime candidates for the application of PCM devices. In this paper, the effects of Se-Te in the phase change characteristics of In-Se-Te material are investigated by X-ray diffraction, Field emission scanning electron microscopy, the I–V measurement and the optical transmittance. The resistance ratio between the amorphous and crystalline states of In2(Te0.98Se0.02)3, In2(Te0.94Se0.06)3 and In2(Te0.90Se0.1)3 thin films are about two orders of magnitude. The stoichiometric phase change from In2(Te1-xSex)3 to In2Se3 and In2Te3 phases in all the samples have been observed from the temperature dependent I–V characteristics. The electrical switching occurs at 80 °C, Further rise in temperature leads no change in the threshold voltage after switching. For the In2(Te0.98Se0.02)3, In2(Te0.94Se0.06)3 and In2(Te0.90Se0.1)3 films, the forward biased current/threshold voltages are found to be about 8 μA/4.2 V, 6 μA/3.00 V and 4 μA/2.8 V respectively. The In2(Te1-xSex)3 thin film showed the high resistance state at low voltage region. However, when it reaches the threshold voltage, the resistance drastically reduced through the formation of conducting path. From these studies, it can be concluded that the effective way to enhance the comprehensive performance of In-Se-Te system is by varying the concentrations of the Te and Se and it may find potential application in switching volatile PCM devices.

КООРДИНАЦІЙНІ СПОЛУКИ КОБАЛЬТУ ТА КУПРУМУ З КАФ ЛІГАНДОМ N,N'-ДИБЕНЗИЛ-N''-ТРИХЛОРАЦЕТИЛФОСФОРТРИАМІДОМ

Сarbacylamidophosphates is a class of organic compounds having a composition -C(O)NHP(O)=. The presence of both peptide and phosphoramidic groups in the same molecule causes a wide range of inherent biological properties. On the basis of the ligand of the carbacylamide phosphorus type (CAPh ligand) N, N'-dibenzyl-N"-trichloroacetylphosphoric triamide (HL), di- and tetramer coordination compounds were synthesized: cobalt (II) Co2L4(СH3OH)2 and copper (ІI) Cu4L4(OCH3)4. The composition and structure of the synthesized compounds was studied using the methods of IR spectroscopy, thermogravimetric and X-ray diffraction analysis. The bidentate-cyclic coordination of ligands through oxygen atoms of the phosphoryl and carbonyl groups was established on the basis of Х-ray structural analysis data. In the Co2L4(СH3OH)2 complex ionic cobalt associates together forming centroscopic dimers due to the bridging function of the phosphoryl group. The coordination sphere also includes methanol molecules, which are coordinated to the metal atom and additionally linked to the oxygen atom of the carbonyl group by hydrogen bonding, which can be considered as an additional stabilizing factor in the formation of the dimeric structure. The copper compound is a Cu4L4(OCH3)4 tetramer, in which methylate ion through µ3-bridging coordination bind four copper atoms to a tetramer. According to the thermogravimetric data, the first mass loss for the cobalt complex is observed in the range from 80°C to 150°C and corresponds to the loss of two methanol molecules. On the TGA curve, two exothermic effects are observed at temperatures of 218°C and 269°C, which are due to the process of oxidative degradation of organic ligands. Unlike the compound of cobalt, the tetramer complex of copper contains methylate ion, therefore the complex is resistant to a temperature of 110°С; with further rise in temperature there is a destruction of the organic part of this complex. The DTA curve shows an exothermic effect at a temperature of 168°C. Residues after the destruction of the complexes correspond to polyphosphates of copper and cobalt.

Структурные и термоэлектрические свойства оптически прозрачных тонких пленок на основе одностенных углеродных нанотрубок

AbstractThin films have been produced via a spray method from commercially available single-walled carbon nanotubes (SWCNTs). A SWCNT film thickness has ranged from ~10 to ~80 nm. The SWCNT diameter has accepted values of 1.6–1.8 nm. The existence of SWCNTs longer than 10 μm is established. The optimal thickness of a SWCNT thin film is found to be ~15 nm at which the transmittance exceeds 85%. The specific resistance of SWCNT thin films goes from ~1.5 × 10^–3 to ~3 × 10^–3 Ohm cm at room temperature. The pioneering study of the temperature dependences of the Seebeck coefficient and surface resistance is performed for this type of SWCNT. A surface resistance is found to increase with rising temperature. Furthermore, the Seebeck coefficient of SWCNT thin films weakly depends on temperature. Its value for all samples is evaluated to be ~40 μV/K. According to the sign of the Seebeck coefficient, thin films exhibit hole-type conductivity. Moreover, the power factor of a 15-nm thin SWCNT-film decreases with a temperature increase to 140◦C from the value of approximately ~120 to ~60 μW m^–1 K^–2. A further rise in temperature has led to a gain in the power factor.

A study of environmentally safe obtaining of molybdenum-based alloying material by solid phase extraction

The study has determined an increase of the degree of thermal carbon extraction of the molybdenum oxide concentrate from 11 % to 97 % with an increase in the processing temperature from 873 K to 1373 K, respectively. A further rise in temperature to 1473 K led to a reduction in the degree of recovery to 89 %. The recovery products after treatment at 873–1073 K mostly consisted of MoO 2 with some Mo and Mo 2 C manifestations. Treatment at 1223–1473 K provided a predominance of Mo and Mo 2 C as to the oxide component. The microstructure of the recovery products was spongy and disordered with varying degrees of sintering, depending on the processing temperature. The alloying of R6M5 steel with the new molybdenum material in experimental industrial conditions provided an increase in the Mo uptake rate from 88.9 % to 95.0 % compared with the standard technology. Improvement of environmental safety is achieved by replacing carbon monoxide and aluminothermic melting of ferroalloy production of Mo with the latest methods of powder metallurgy.

Variations of snow accumulation rate in Central Antarctica over the last 250 years

The present-day global climate changes, very likely caused by anthropogenic activity, may potentially present a serious threat to the whole human civilization in a near future. In order to develop a plan of measures aimed at elimination of these threats and adaptation to these undesirable changes, one should deeply understand the mechanism of past and present (and thus, future) climatic changes of our planet. In this study we compare the present-day data of instrumental observations of the air temperature and snow accumulation rate performed in Central Antarctica (the Vostok station) with the reconstructed paleogeographic data on a variability of these parameters in the past. First of all, the Vostok station is shown to be differing from other East Antarctic stations due to relatively higher rate of warming (1.6 °C per 100 years) since 1958. At the same time, according to paleogeographic data, from the late eighteenth century to early twenty-first one the total warming amounted to about 1 °C, which is consistent with data from other Antarctic regions. So, we can make a conclusion with high probability that the 30-year period of 1985–2015 was the warmest over the last 2.5 centuries. As for the snow accumulation rate, the paleogeographic data on this contain a certain part of noise that does not allow reliable concluding. However, we found a statistically significant relationship between the rate of snow accumulation and air temperature. This means that with further rise of temperature in Central Antarctica, the rate of solid precipitation accumulation will increase there, thus partially compensating increasing of the sea level.

Influence of multi-cavity dislocation distribution on thermal conductance in graphene nanoribbons

Using non-equilibrium Green's function method and keeping the zigzag carbon chains unchanged, we investigate the transmission rate of acoustic phonon and the reduced thermal conductance in the graphene nanoribbons with three cavities. The results show that the reduced thermal conductance approaches to 32kB2 T/(3h) in the limit T0 K. Due to the fact that only long wavelength acoustic phonons with zero cutoff frequency are excited at such low temperatures, the scattering influence on the long wavelength acoustic phonons by the dislocation distribution of three cavities in the graphene nanoribbons can be ignored and these phonons can go through the scattering region perfectly. As the temperature goes up, the reduced thermal conductance decreases. This is because the high-frequency phonons are excited and these high-frequency phonons are scattered easily by the scattering structures. With the further rise of temperature, acoustic phonon modes with the cutoff frequency greater than zero are excited, which leads to a rapid increase of the reduced thermal conductance. This study shows that in higher frequency region, the transmission spectra display complex peak-dip structures, which results from the fact that in higher frequency region, more phonon modes are excited and scattered in the middle scattering region with three cavities, and the scattering phonons are coupled with the incident phonons. When the three cavities are aligned perpendicularly to the edge of the graphene nanoribbons, the scattering from low-frequency phonons by the scattering structures is smallest, which leads to the fact that the reduced thermal conductance is largest at low temperatures; however, at high temperatures, the reduced thermal conductance is smallest when the three cavities is aligned perpendicularly to the edge of the graphene nanoribbons. This is because the scattering from high-frequency phonons by the scattering structures is biggest. These results show that the acoustic phonon transport and the reduced thermal conductance are dependent on the relative position of the three cavities. In addition, the dislocation distribution of the three cavities can only modulate obviously the high-temperature thermal conductance of the in-plane modes (IPMs). This is because the change of the relative position of the quantum dots can only modulate greatly the high-frequency phonon transmission rate and less modulate the low-frequency phonon transmission rate of the IPMs. However, the dislocation distribution of the three cavities can adjust obviously not only the high-temperature thermal conductance of the flexural phonon modes (FPMs), but also the low-temperature thermal conductance of the FPMs. This is because the change of the relative position of the three cavities can modulate greatly phonon transmission rates of flexural phonon modes in the low-frequency and high-frequency regions. These results provide an effective theoretical basis for designing the thermal transport quantum devices based on graphene nanoribbons.

Temperature and high fluence induced ripple rotation on Si(100) surface

The topography evolution of Si(100) surface due to oblique incidence low energy ion beam sputtering (IBS) is investigated. Experiments were carried out at different elevated temperatures from 20 °C–450 °C and at each temperature, the ion fluence is systematically varied in a wide range from 1 × 1018 cm−2 to 1 × 1020 cm−2. The ion sputtered surface morphologies are characterized by atomic force microscopy and high-resolution cross-sectional transmission electron microscopy. At room temperature, the ion sputtered surfaces show periodic ripple nanopatterns where their wave-vector remains parallel to ion beam projection for the entire fluence range. With an increase of substrate temperature, these patterns tend to demolish and reduce into randomly ordered mound-like structures around 350 °C. A further rise in temperature above 400 °C leads orthogonally rotated ripples beyond fluence 5 × 1019 cm−2. All the results are discussed combining the theoretical framework of linear, non-linear and recently developed mass redistribution continuum models of pattern formation by IBS. These results have technological importance regarding the control over ion-induced pattern formation, as well providing useful information for further progress in the theoretical field.

Investigation the Risk of Spontaneous Combustion in Barapukuria Coal Mine, Dinajpur, Bangladesh

Spontaneous combustion of coal is one of the major problems in the coal mine. The fire may occur due to exogenous and endogenous causes, by which coal liberated heat to the air or heat absorbed into it. It causes loss of production, as well as economical or financial losses and polluted the environment. If, the heat liberated during this process is allowed to accumulate, the rate of reaction increases exponentially and there is a further rise in temperature that generates the flame and produce CO, CO2, CH4, N2, O2 etc. In addition, the heat generated within coal affected by different factors such moisture, ash, volatile matter etc. of coal. This paper deals with the oxidation and spontaneous combustion risk in Barapukuria underground longwall coal mine, Dinajpur, Bangladesh. In this study, the laboratory analyses (proximate analyses) shows the inherent and the total moisture content value is average 2.73% and 5.82% to 12.75%, respectively. It indicates that these moisture contents are moderately liable to self heating. The less ash content value (av.13.2%) shows, it is less liable to spontaneous combustion. In addition to this, the temperature and concentration of some mine gases (CO, N2, O2) were monitored to calculate the Graham’s ratio. According to Graham’s ratio, the longwall faces have high oxidation risk and medium combustion risk. Therefore, the actual control of spontaneous combustion of coal is important to save coal mine from mine fires and also provides a real opportunity to improve the financial performance of the overall organization.

Study of temperature dependent zirconium silicide phases in Zr/Si structure by differential scanning calorimetry

The differential scanning calorimetry (DSC) technique is employed to study the formation of different silicide compounds of Zr thin-film deposited on a 100 μm-thick Si (1 0 0) substrate by dc sputtering. A detailed analysis shows that silicide layers start growing at ∼246 °C that changes to stable ZrSi2 at 627 °C via some compounds with different stoichiometric ratios of Zr and Si. It is further observed that oxygen starts reacting with Zr at ∼540 °C but a stoichiometric ZrO2 film is formed after complete consumption of Zr metal at 857 °C. A further rise in temperature changes a part of ZrSi2 to Zr-Silicate. The synchrotron radiation-based grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy studies also corroborate the above findings. Atomic force microscopy is also carried out on the samples. It is evident from the observations that an intermixing and nucleation of Zr and Si occur at lower temperature prior to the formation of the interfacial silicate layer. Zr-Silicate formation takes place only at a higher temperature.

The role of deposition temperature and catalyst thickness in graphene domains on Cu

Few layered graphene is synthesized on Cu foil by thermal chemical vapor deposition. We have investigated the effect of temperature and catalyst’s thickness on graphene domain length and number. The synthesized graphene was characterized using Raman spectroscopy and scanning electron microscopy. Raman spectroscopy results show that D-peak intensity increases with an increasing temperature which revealing that some defects have been generated during synthesis on Cu surface synthesis at higher temperature. It also has been observed that increasing in temperatures result in more intense 2D peaks. Although for further rise in temperature, although the number of graphene domain increases and the graphene domain length reduces. Our results provide important guidance toward the synthesis of high quality graphene films.

Isothermal and dynamic oxidation behaviour of Mo–W doped carbon-based coating

The oxidation behaviour of Mo–W doped carbon-based coating (Mo–W–C) is investigated in elevated temperature (400–1000°C). Strong metallurgical bond between Mo–W–C coating and substrate prevents any sort of delamination during heat-treatment. Isothermal oxidation tests show initial growth of metal oxides at 500°C, however graphitic nature of the as-deposited coating is preserved. The oxidation progresses with further rise in temperature and the substrate is eventually exposed at 700°C. The performance of Mo–W–C coating is compared with a state-of-the-art DLC(Cr/Cr–WC/W:C–H/a:C–H) coating, which shows preliminary oxidation at 400°C and local delamination of the coating at 500°C leading to substrate exposure. The graphitisation starts at 400°C and the diamond-like structure is completely converted into the graphite-like structure at 500°C. Dynamic oxidation behaviour of both the coatings is investigated using Thermo-gravimetric analysis carried out with a slow heating rate of 1°C/min from ambient temperature to 1000°C. Mo–W–C coating resists oxidation up to ∼800°C whereas delamination of DLC(Cr/Cr–WC/W:C–H/a:C–H) coating is observed beyond ∼380°C. In summary, Mo–W–C coating provides improved oxidation resistance at elevated temperature compared to DLC(Cr/Cr–WC/W:C–H/a:C–H) coating.

Modeling impacts and adaptations of climate change on soybean (Glycine max) production in Himachal Pradesh, India

Soybean [Glycine max (L.) Merr.], one of the commercial crops grown under rainfed conditions in Himachal Pradesh produced low yields due to uneven weather conditions. This study presents outcome of a simulation study to evaluate the impact of projected climate change on yields of soybean and simulated adaptations in the face of climate change. During past three decades the region has experienced increase in temperature and decrease in rainfall. The validated InfoCrop model runs for 20 years (1989-2008) to assess impacts of the projected climate change on soybean production. The Root Mean Square Error (RMSE) values were 8.8 days and 190.4 kg/ha for days to maturity and crop yield between simulated and observed yields of five years (2004-08) under two sowing environments. The elevated levels of 50 and 100 parts per million (ppm) carbon dioxide (CO2) increased soybean yield by 5.0 to 10.2%. The projected yield losses due to elevated levels of temperature by 1 and 2oC alone ranged between 1.3 to 3.5 and 4.5 to 6.0 percent respectively, for all planting windows. The elevated temperature of 1oC coupled with 50 ppm elevated level of carbon dioxide (420ppm) showed increase in yield up to 4.9 percent with shortened average growing period up to 2 days. The further rise of temperature to 2oC with 50 ppm elevated level of carbon dioxide caused increase in simulated yield up to 2.3 percent in simulations of 1989-2008 compared to control conditions. Similarly, 100 ppm elevated level of carbon dioxide with 1oC rise in temperature caused increase in yield between 8.8 to 10.2 percent in all planting windows whereas it was 3.1 to 3.9 percent lesser in 2oC rise in temperature with 100 ppm elevated level of carbon dioxide with compared to 1oC rise in temperature. The climatic grid of 10 percent reduction in rainfall from recent decade 1998-2008 showed small decrease in yield but yield increase of 5.2 to 8.5 percent was observed when coupled with 50 ppm elevated carbon dioxide and 1oC rise in temperature. Hence rise of temperature with elevated carbon dioxide in general increase the yield in region.

Study of the effect of electrolyte and temperature on the critical micelle concentration of dodecyltrimethylammonium bromide in aqueous medium

The effect of three organic electrolytes, viz. tetrapropylammonium bromide (C12H28NBr), tetrabutylammonium bromide (C16H36NBr), and tetrapentylammonium bromide (C20H44NBr) (0.01mol·kg−1) on the aggregation behaviour of a cationic surfactant, dodecyltrimethylammonium bromide (DTAB) (1.5 to 29.8)mmol·kg−1 in aqueous medium over a wide temperature range (288.15 to 318.15)K has been studied by conductivity measurements. From conductivity versus surfactant concentration plots, the critical micelle concentration (CMC) of DTAB has been determined, which shows that all the investigated electrolytes promote the aggregate formation of DTAB. The CMC values decrease to a certain minimum value around T=298.15K in all cases and then increase with further rise in temperature, displaying a typical U-shaped behaviour. Further, from the temperature dependence of CMC values, various thermodynamic parameters of micellization viz. standard free energy change (ΔGmo), standard enthalpy change (ΔHmo) and standard entropy change (ΔSmo) have been calculated. The values of ΔGmo, ΔHmo and ΔSmo indicate that the electrolytes have arbitrated DTAB aggregation and micellization process is both enthalpy as well as entropy controlled. The results reveal the major role of hydrophobic interactions in the present (surfactant+electrolyte+water) ternary system. Fluorescence probe study has also been employed to affirm the CMC values obtained from conductivity measurements.

Studies on the solubility of hydrogen in molten Pb83Li17 eutectic alloy

Lead–lithium eutectic (Pb87Li17) alloy is a candidate material to be used as a secondary tritium breeder, neutron multiplier and heat transfer agent in the fusion reactor. The tritium thus produced in the alloy may be soluble or appear as a new phase of lithium-tritides and/or lead-tritides, which eventually affect the performance of Pb83Li17 eutectic. Therefore, solubility of tritium in the alloy at the operating conditions of the fusion reactor is a subject matter of investigation. Tritium being the isotope of hydrogen behaves more or less similar to the hydrogen. In the present investigation the solubility of hydrogen in the Pb83Li17 has been investigated as a function of temperature and pressure. It was found that, hydrogen solubility in the Pb87Li17 alloy is almost constant above 350 °C. Hydrogen solubility increases with increase of temperature up to 400 °C. Hydrogen solubility is 120 ppm at 400 °C and 800 Torr hydrogen pressure. The solubility decreases on further rise in temperature from 400 °C. However, at all the temperatures hydrogen solubility increased with increase of partial pressure of hydrogen.

The Compression Behavior of Contaminated Clay under Coupled Temperature and Chemical Solution

The compressibility of contaminated soil was analyzed through the consolidation test. The results show that, with increasing of the acid concentration, the soil compression is increased. The compression of soil contaminated by alkaline is larger than the soil contaminated by acid. The temperature at beginning section plays catalytic effect on soil structural damage, and the amount of compression of the soil is significantly increased with an increase of temperature. When temperature is increased to a certain value, the amount of compression decreases conversely, this may the cohesion between the soil particles is strengthened. However, with the further rise in temperature, the soil structure shows irreversible damage.

Multiphase and multicomponent transport with phase change during meat cooking

A multiphase model based on unsaturated flow in a hygroscopic porous medium, which accounts for the important physical phenomena that take place during thermal treatment of meat, is developed. Frozen meat is considered as a porous solid comprising of water, fat and protein with gas trapped in its pores. As it is heated, water and fat melt, and, are gradually released from the solid protein matrix to the pore space. With further rise in temperature, liquid water evaporates. Since four fluid components (liquid water phase, liquid fat phase, water vapor and air) are present in the pore space, a mass balance equation is written for each component. Local thermal equilibrium assumption leads to one energy balance equation for the whole system. The model is validated for double-sided contact heating of hamburger patties by comparing temperature and moisture profiles with experimental studies. Dominant modes of transport are identified.

Thermal analysis of tetraethylammonium and benzyltrimethylammonium montmorillonites

Abstract Na-montmorillonite was loaded with tetraethylammonium cations (TEA) or with benzyltrimethylammonium cations (BTMA) by replacing 77 and 81% of the exchangeable Na with TEA or BTMA, labeled TEA-MONT and BTMA-MONT, respectively. TEA- and BTMA-MONT were heated in air up to 900 °C. Thermally treated organoclays are used in our laboratory as sorbents of organic compounds from water. The two organoclays were studied by TG and DTG in air and under nitrogen. Carbon content in each of the heated sample was determined. They were diffracted by X-ray, and fitting calculations of d(001) peaks were performed on each diffractogram. TG and thermo-C analysis showed that at 150 and 250 °C both organoclays lost water but not intercalated ammonium cations. DTG peak of the first oxidation step of the organic cation with the formation of low-temperature stable charcoal (LTSC) appeared at 364 and 313 °C for TEA- and BTMA-MONT, respectively. The charcoal was gradually oxidized by air with further rise in temperature. DTG...

Dynamics of methanogenesis and methanotrophy in tropical paddy soils as influenced by elevated CO2 and temperature interaction

Response of methanogenesis and methanotrophy to elevated carbon dioxide (CO2) could be affected by changes in soil moisture content and temperature. In soil microcosms contained in glass bottles and incubated under laboratory conditions, we assessed the impact of elevated CO2 and temperature interactions on methanogenesis and methanotrophy in alluvial and laterite paddy soils of tropical origin. Soil samples were incubated at ambient (370 μmol mol−1) and elevated (600 μmol mol−1) CO2 concentrations at 25, 35 and 45 °C under non-flooded and flooded conditions for 60 d. Under flooded condition, elevated CO2 significantly increased methane (CH4) production while under non-flooded condition, only marginal increase in CH4 production was observed in both the soils studied and the increase was significantly enhanced by further rise in temperature. Increased methanogenesis as a result of elevated CO2 and temperature interaction was mostly attributed to decreased soil redox potential, increased readily mineralizable carbon, and also noticeable stimulation of methanogenic bacterial population. In contrast to CH4 production, CH4 oxidation was consistently low under elevated CO2 concentration and the decrease was significant with rise in temperature. The low affinity and high affinity CH4 oxidation were faster under non-flooded condition as compared to flooded condition. Admittedly, decreased low and high affinity CH4 oxidation as a result of elevated CO2 and temperature interaction was related to unfavorable lower redox status of soil and the inhibition of CH4-oxidizing bacterial population.

Thermal analyis of hexadecyltrimethylammonium–montmorillonites

Na-montmorillonite (Na-MONT) was loaded with hexadecyltrimethylammonium cations (HDTMA) by replacing 41 and 90% of the exchangeable Na with HDTMA, labeled OC-41 and OC-90, respectively. Na-MONT, OC-41, and OC-90 were heated in air up to 900 °C. Unheated and thermally treated organoclays heated at 150, 250, 360, and 420 °C are used in our laboratory as sorbents of different hazardous organic compounds from waste water. In order to get a better knowledge about the composition and nature of the thermally treated organoclays Na-MONT and the two organo-clays were studied by thermogravimetry (TG) in air and under nitrogen. Carbon and hydrogen contents in each of the thermal treated sample were determined and their infrared spectra were recorded. The present results showed that at 150 °C both organoclays lost water but not intercalated HDTMA cations. At 250 °C, many HDTMA cations persisted in OC-41, but in OC-90 significant part of the cations were air-oxidized into H2O and CO2 and the residual carbon formed charcoal. After heating both samples at 360 °C charcoal was present in both organo clays. This charcoal persisted at 420 °C but was gradually oxidized by air with further rise in temperature. TG runs under nitrogen showed stepwise degradation corresponding to interlayer water desorption followed by decomposition of the organic compound, volatilization of small fragments and condensation of non-volatile fragments into quasi-charcoal. After dehydroxylation of the clay the last stages of organic matter pyrolysis and volatilization occurred.

Effect of chlorine on volatilization of Na, K, Pb, and Zn compounds from municipal solid waste during gasification and melting in a shaft-type furnace

In the present work, a shaft-type furnace model in which the furnace column is divided into multiple cells was proposed and equilibrium reaction calculation software was used to describe the model. The model was used to study the effects of gasification and melting conditions such as temperature, oxygen partial pressure, and chlorine content on the volatilization behaviors of the low-boiling-point metals Na, K, Pb, and Zn during the gasification and melting process of municipal solid waste in a shaft-type furnace. Consequently, the volatilization ratios of Na, K, Pb, and Zn compounds in the exhaust gas from a pilot plant shaft-type furnace were found to be in good agreement with the calculation results, and the Na, K, Pb, and Zn compounds were volatilized mainly as metal chlorides in the temperature range up to approximately 1173 K. With a further rise in temperature, these low-boiling point metals were volatilized as metallic forms. It was found that almost 100% of Pb and Zn compounds were volatilized regardless of the chlorine content in municipal solid waste; in contrast, the volatilization rates of Na and K increased when the chlorine content increased. Finally, Na, K, Pb, and Zn compounds were converted from reduced metals to metal chlorides such as NaCl, KCl, PbCl2, and ZnCl2 with an increase in the ratio of chlorine to each metal.