This paper presents the equilibrium desorption isotherms and the isosteric heat of sorption of a mixture containing mechanically dewatered fermentation residue(obtained from a blend of chicken,swine and cattle manure)...This paper presents the equilibrium desorption isotherms and the isosteric heat of sorption of a mixture containing mechanically dewatered fermentation residue(obtained from a blend of chicken,swine and cattle manure)used in biogas plants and corn spoiled silage in a ratio of 2:1.The moisture desorption isotherms of the fermentation residue were determined at 32°C,40°C and 80°C and in the relative humidity range of 0.057/1 using static gravimetric method.Mathematical equations were used to analyze the desorption data of Modified Henderson,Modified Halsey,Modified Oswin,Modified Chung–Pfost and Modified GAB models.The constants of the model equations were calculated by non-linear regression analysis.The Modified Henderson model fitted to the desorption isotherm data well.Using the proposed function,the final moisture content of the material can be determined as long as it can be dried in infinite time with the drying gas in the given conditions.The isosteric heat of desorption was calculated by using the Modified Henderson model in the studied temperature range based on the Clausius–Clapeyron equation.The isosteric heat varied between 46 k J·mol-1 and 67 k J·mol-1 at moisture levels 1.91 b Xe<4.05 kgH2O·kgdP-1 for the material.展开更多
Hydrogen plays an important role in the formation of quench cracks of structural steels. To clarify hydrogen ab- sorption and desorption during heat treatment of AISI 4140 steel, thermal desorption spectrometry （TDS...Hydrogen plays an important role in the formation of quench cracks of structural steels. To clarify hydrogen ab- sorption and desorption during heat treatment of AISI 4140 steel, thermal desorption spectrometry （TDS） analysis was carried out for the specimens in the as-rolled, as quenched, and quenched and tempered conditions. Results show that hydrogen content increased from 0. 127 ×10 6 in the as-rolled specimen to 0. 316 × 10-6 in the as-oil-quenched specimen. After tempering at 200 ℃, the hydrogen content in the oil-quenched specimen decreased to 0. 155 × 10-6 , and the peak temperature of hydrogen desorption increased from 200 to 360 ℃. From the dependence of hydrogen content in the as-quenched specimens on austenitizing time, it can be deduced that hydrogen absorption occurs during austenitizing. The simulation of hydrogen absorption contributes to a better understanding on the distribution of hy- drogen during the heat treatment in structural steels.展开更多
High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated ...High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated soil can help predict accurately the transient temperature distribution in a remediation site,for the purpose of energy conservation.However,such data are rarely reported for PH-contaminated soil.In this study,by taking diesel as a representative example for PHs,soil samples with constant dry bulk density but different diesel mass concentrations ranging from 0% to 20% were prepared,and the variations of their thermal conductivity,specific heat capacity and thermal diffusivity were measured and analyzed over a wide temperature range between 0℃ and 120℃.It was found that the effect of diesel concentration on the thermal conductivity of soil is negligible when it is below 1%.When diesel concentration is below 10%,the thermal conductivity of soil increases with raising the temperature.However,when diesel concentration becomes above 10%,the change of the thermal conductivity of soil with temperature exhibits the opposite trend.This is mainly due to the competition between soil minerals and diesel,because the thermal conductivity of minerals increases with temperature,whereas the thermal conductivity of diesel decreases with temperature.The analysis results showed that,compared with temperature,the diesel concentration has more significant effects on soil thermal conductivity.Regardless of the diesel concentration,with the increase of temperature,the specific heat capacity of soil increases,while the thermal diffusivity of soil decreases.In addition,the results of a control experiment exhibited that the relative differences of the thermal conductivity of the soil samples containing the same concentration of both diesel and a pure alkane are all below 10%,indicating that the results obtained with diesel in this study can be extended to the family of PHs.A theoretical prediction model was proposed based on cubic fractal and thermal resistance analysis,which confirmed that diesel concentration does have a significant effect on soil thermal conductivity.For the sake of practical applications,a regression model with the diesel concentration as a primary parameter was also proposed.展开更多
为了促进煤层气与页岩气在储层评价与开发方式选择上的相互借鉴,进行了煤与页岩吸附甲烷的对比试验。通过多温度点页岩气和煤层气吸附/解吸试验,计算升压过程与解吸过程吸附热差异,发现热演化程度基本一致时,极限吸附热计算结果表明:煤...为了促进煤层气与页岩气在储层评价与开发方式选择上的相互借鉴,进行了煤与页岩吸附甲烷的对比试验。通过多温度点页岩气和煤层气吸附/解吸试验,计算升压过程与解吸过程吸附热差异,发现热演化程度基本一致时,极限吸附热计算结果表明:煤层气在升压吸附时放热量19.148k J/mol,小于降压过程吸热量23.966 k J/mol,降压解吸难以持续;页岩气在升压吸附时放热量44.624k J/mol,大于降压过程吸热量32.656 k J/mol,降压促进吸附/解吸平衡向解吸方向移动。因此,利用排水降压进行煤层气开采时,应重视持续解吸技术的研究。展开更多
基金supported by Hungarian Ministry of Human Capacities(NTP-NFTO-18-B-0420)supported by the Higher Education Excellence Program of the Ministry of Human Capacities in the frame of Water science&Disaster Prevention research area of Budapest University of Technology and Economics(BME FIKP-VíZ)the Hungarian Scientific Research Fund(NKFIH/PD-116326).
文摘This paper presents the equilibrium desorption isotherms and the isosteric heat of sorption of a mixture containing mechanically dewatered fermentation residue(obtained from a blend of chicken,swine and cattle manure)used in biogas plants and corn spoiled silage in a ratio of 2:1.The moisture desorption isotherms of the fermentation residue were determined at 32°C,40°C and 80°C and in the relative humidity range of 0.057/1 using static gravimetric method.Mathematical equations were used to analyze the desorption data of Modified Henderson,Modified Halsey,Modified Oswin,Modified Chung–Pfost and Modified GAB models.The constants of the model equations were calculated by non-linear regression analysis.The Modified Henderson model fitted to the desorption isotherm data well.Using the proposed function,the final moisture content of the material can be determined as long as it can be dried in infinite time with the drying gas in the given conditions.The isosteric heat of desorption was calculated by using the Modified Henderson model in the studied temperature range based on the Clausius–Clapeyron equation.The isosteric heat varied between 46 k J·mol-1 and 67 k J·mol-1 at moisture levels 1.91 b Xe<4.05 kgH2O·kgdP-1 for the material.
基金Item Sponsored by National Basic Research Program(973 Program)of China(2010CB630800)
文摘Hydrogen plays an important role in the formation of quench cracks of structural steels. To clarify hydrogen ab- sorption and desorption during heat treatment of AISI 4140 steel, thermal desorption spectrometry （TDS） analysis was carried out for the specimens in the as-rolled, as quenched, and quenched and tempered conditions. Results show that hydrogen content increased from 0. 127 ×10 6 in the as-rolled specimen to 0. 316 × 10-6 in the as-oil-quenched specimen. After tempering at 200 ℃, the hydrogen content in the oil-quenched specimen decreased to 0. 155 × 10-6 , and the peak temperature of hydrogen desorption increased from 200 to 360 ℃. From the dependence of hydrogen content in the as-quenched specimens on austenitizing time, it can be deduced that hydrogen absorption occurs during austenitizing. The simulation of hydrogen absorption contributes to a better understanding on the distribution of hy- drogen during the heat treatment in structural steels.
基金financially supported by the National Key Research and Development Program (project No.2019YFC1805700,program No.2019YFC1805701)。
文摘High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated soil can help predict accurately the transient temperature distribution in a remediation site,for the purpose of energy conservation.However,such data are rarely reported for PH-contaminated soil.In this study,by taking diesel as a representative example for PHs,soil samples with constant dry bulk density but different diesel mass concentrations ranging from 0% to 20% were prepared,and the variations of their thermal conductivity,specific heat capacity and thermal diffusivity were measured and analyzed over a wide temperature range between 0℃ and 120℃.It was found that the effect of diesel concentration on the thermal conductivity of soil is negligible when it is below 1%.When diesel concentration is below 10%,the thermal conductivity of soil increases with raising the temperature.However,when diesel concentration becomes above 10%,the change of the thermal conductivity of soil with temperature exhibits the opposite trend.This is mainly due to the competition between soil minerals and diesel,because the thermal conductivity of minerals increases with temperature,whereas the thermal conductivity of diesel decreases with temperature.The analysis results showed that,compared with temperature,the diesel concentration has more significant effects on soil thermal conductivity.Regardless of the diesel concentration,with the increase of temperature,the specific heat capacity of soil increases,while the thermal diffusivity of soil decreases.In addition,the results of a control experiment exhibited that the relative differences of the thermal conductivity of the soil samples containing the same concentration of both diesel and a pure alkane are all below 10%,indicating that the results obtained with diesel in this study can be extended to the family of PHs.A theoretical prediction model was proposed based on cubic fractal and thermal resistance analysis,which confirmed that diesel concentration does have a significant effect on soil thermal conductivity.For the sake of practical applications,a regression model with the diesel concentration as a primary parameter was also proposed.
文摘为了促进煤层气与页岩气在储层评价与开发方式选择上的相互借鉴,进行了煤与页岩吸附甲烷的对比试验。通过多温度点页岩气和煤层气吸附/解吸试验,计算升压过程与解吸过程吸附热差异,发现热演化程度基本一致时,极限吸附热计算结果表明:煤层气在升压吸附时放热量19.148k J/mol,小于降压过程吸热量23.966 k J/mol,降压解吸难以持续;页岩气在升压吸附时放热量44.624k J/mol,大于降压过程吸热量32.656 k J/mol,降压促进吸附/解吸平衡向解吸方向移动。因此,利用排水降压进行煤层气开采时,应重视持续解吸技术的研究。
