Experimental and Numerical Investigation of Enhancement of Heat and Mass Transfer in Adsorbent Beds

ＥｘｐｅｒｉｍｅｎｔａｌａｎｄＮｕｍｅｒｉｃａｌＩｎｖｅｓｔｉｇａｔｉｏｎｏｆＥｎｈａｎｃｅｍｅｎｔｏｆＨｅａｔａｎｄＭａｓｓＴｒａｎｓｆｅｒｉｎＡｄｓｏｒｂｅｎｔＢｅｄｓＬｉｕＺｈｅｎｙａｎ；ＦｕＺｈｕｍａｎ；ＧｅＸｉｎｓｈｉ；ＳｕＹｕｅｈｏｎｇ；...     

Co-pyrolysis of waste polypropylene and rice bran wax‒ production of biofuel and its characterization

The present study aims to investigate the interaction during co-pyrolysis of Polypropylene (PP) and Rice bran wax (RBW). Initial characterization of feedstock was found to be suitable to carry out further experimental sets. Further, the pyrolysis experiments of PP, RBW and different blends (1:1, 1:2, 1:3, 2:1 and 3:1) were carried out in a semi-batch reactor. As per TGA analysis the temperature range between 400 °C and 650 °C at a constant heating rate of 25 °C/min was determined. The maximum liquid yield of PP, RBW was approximately 76%, 86% at the temperature of 500 °C and 600 °C respectively. Whereas maximum liquid yield from co?pyrolysis was obtained at 1:3 blend i.e. 81% at 550 °C.GC?MS results inferred the highest percentage of hydrocarbon whereas 1:3 blends has lower oxygen containing groups than RBW in liquid products. FTIR data of all blends indicates higher range of alkyl and aromatic compounds. H1 NMR results also confirmed the higher compounds into aliphatic region than aromatics or heteroaromatics groups. Further, most of the fuel properties of 1:3 blend falls within the range of gasoline and diesel properties. Study was extended to know crystallization behaviour of fuel by DSC analysis from two consecutive heating and cooling cycles of ?50 to 60 °C and reversed till ?50 °C at 10 °C min ?1. Two peaks at ?24 °C and 26 °C were observed during heating cycle whereas single peak at 23 °C during cooling cycle. 1:3 blend residual char characterization was also included in the work. Unfortunately, the SEM and BET results inferred that the char was not highly porous.     

Experiments and Modelling of Coal Devolatilization

ＥｘｐｅｒｉｍｅｎｔｓａｎｄＭｏｄｅｌｌｉｎｇｏｆＣｏａｌＤｅｖｏｌａｔｉｌｉｚａｔｉｏｎ￥ＱｉｕＫｕａｎｒｏｎｇ（Ｄｅｐｔ．ｏｆＣｏａｌＵｔｉｌｉｚａｔｉｏｎ，ＣｈｉｎａＵｎｉｖｅｒｓｉｔｙｏｆＭｉｎｉｎｇａｎｄＴｅｃｈｎｏｌｏｇｙ，Ｘｕｚｈｏｕ２...     

Theoretical and technological aspects of flow batteries：Measurement of state of charge

电池实际可放出的瓦时容量与实际可放出的最大瓦时容量的比值定义为荷电状态,准确测定荷电状态对储能应用十分重要。本文从理论和应用角度,讨论全钒液流电池荷电状态的理论概念、工程定义和主要影响因素;提出2种确定最大瓦时容量的方法,其中实测法准确度更高,包含钒离子跨膜迁移、水分子扩散、负极电解液析氢和被氧化的信息,用于表征储能系统的荷电状态具有实际价值;阐述最大瓦时容量、电化学瓦时容量和理论瓦时容量的区别与联系。所提出的荷电状态确定方法,能够用于全钒液流电池SOC的估计。     

Analysis of the Pyrolysis of Solid Recovered Fuel and Its Sorted Components by using TG-FTIR and DAEM

Currently,waste disposal has been highlighted strategically all over the world.Solid recovered fuel(SRF) with a high calorific value is manufactured from municipal solid waste(MSW).Thermogravimetric Fourier transform infrared spectroscopy(TG-FTIR) and distributed activation energy model(DAEM) were utilized to study the pyrolysis of the individual components and their mixture(i.e.SRF),which were obtained from a MSW incineration power plant.The best operating conditions were defined by comparing t...     

Application of Exergoeconomics to the Analysis and Optimization of Process Systems

ＡｐｐｌｉｃａｔｉｏｎｏｆＥｘｅｒｇｏｅｃｏｎｏｍｉｃｓｔｏｔｈｅＡｎａｌｙｓｉｓａｎｄＯｐｔｉｍｉｚａｔｉｏｎｏｆＰｒｏｃｅｓｓＳｙｓｔｅｍｓＡｐｐｌｉｃａｔｉｏｎｏｆＥｘｅｒｇｏｅｃｏｎｏｍｉｃｓｔｏｔｈｅＡｎａｌｙｓｉｓａｎｄＯｐｔｉｍｉｚａｔ...     

Review of the Debate and the Development of Thrust Vectoring Technology

InMemoryofafriend,Dr.W.HerbstofMBB,Germany,theso-calledfatheroftheX-31experimentalthrustvectoringfighter,wholosthislifeafewyearsagowhilepilotinghisprivateairplane.BertrandRussell'"Menarebornignorant,notstupid-theyaremadestupidbyeducation."AdmiralHymanRickoverf"Thebestengineersarethosewho,inadditiontotechnicalex-pertise,havehadgoodtrainingintheliberalartsandunderstandtheworldaroundthem."ANoLD-NEWEURoPEANDEBArEONTHRUSTVECToRING"talkofthrnstvectoringi8adistrnction,and..thereisn…     

Experimental determination of emission and laminar burning speeds of α-pinene

Several researches have reported that under certain conditions forest fires with normal behavior suddenly start to propagate at unusual and very fast rate of spread. A thermochemical approach, based on the ignition of a Volatile Organic Compounds (VOCs) cloud, has been proposed previously to explain these accelerating forest fires. Indeed, some vegetal species when heated emit volatile substances. We have shown using a flash pyrolysis apparatus that a typical Mediterranean plant, Rosmarinus officinalis, emits eighteen components, mainly α-pinene. Laminar burning speeds and Markstein lengths as well as flame thicknesses of α-pinene/air premixed flames are determined using the spherical expanding flames method. Experiments are carried out in a spherical vessel at atmospheric pressure. The effects of equivalence ratio (0.7–1.4) and unburned gas temperature (353–453 K) are studied. Combustion characteristics are obtained using a nonlinear methodology. A correlation is developed to calculate the laminar burning speeds as a function of equivalence ratio and temperature. The experimental results are compared to the computed ones of JP-10 and n-decane as well as to those found in the literature for these compounds.     

Design and Prototyping of Micro Centrifugal Compressor

In order to establish the design methodology of ultra micro centrifugal compressor, which is the most important component of ultra micro gas turbine unit, a 10 times of the final target size model was designed, prototyped and tested. The problems to be solved for downsizing were examined and 2-dimensional impeller was chosen as the first model due to its productivity. The conventional ID prediction method, CFD and the inverse design were attempted. The prototyped compressor was driven by using a turbocharger and the performance characteristics were measured.     

Analysis of Entropy Generation of Combined Heat and Mass Transfer in Internal and External Flows with the Assumption of Local Thermodynamic Equilibrium

ＡｎａｌｙｓｉｓｏｆＥｎｔｒｏｐｙＧｅｎｅｒａｔｉｏｎｏｆＣｏｍｂｉｎｅｄＨｅａｔａｎｄＭａｓｓＴｒａｎｓｆｅｒｉｎＩｎｔｅｒｎａｌａｎｄＥｘｔｅｒｎａｌＦｌｏｗｓｗｉｔｈｔｈｅＡｓｓｕｍｐｔｉｏｎｏｆＬｏｃａｌＴｈｅｒｍｏｄｙｎａｍｉｃＥｑｕｉｌｉ...     

Modelling of the Absorption and Desorption Process of Chemical Heat Pumps

A simple model for the desorption and absorption process of the chemical heat pump is presented in this paper, It is based on the assumption of a definite reaction front. The results from m this model are compared with those obtained by finite difference method and it is observed that there is almost no difference between them.     

Transformation and release of potassium during fixed-bed pyrolysis of biomass

To study the release and transformation of fuel K during rapid pyrolysis of biomass, wheat straw, corn stalk and rice hull are pyrolyzed in a fixed-bed reactor system during 400–1000 °C, and weight measurement, elemental composition analysis, and chemical fractionation analysis are performed. The effects of fuel type, pyrolysis temperature, co-pyrolysis of different fuels, and water washing pretreatment are discussed. The results show that for all biomass fuels, the released K is far less than the water-soluble K and a sudden increase occurs in the fraction of ion-exchangeable K at 400 °C, whereas a significant increase happens in the fraction of insoluble K above 800 °C. Wheat straw releases less than 5% of K at 400 and 500 °C. As temperature rises, the K release increases abruptly and around 40% of K enters the gas phase at 1000 °C. Rice hull has a slow and linear K release with increasing pyrolysis temperature. Corn stalk has the lowest K release during 400–800 °C. Co-pyrolysis of wheat straw and rice hull reduce the K release at 1000 °C, and the biggest decrement is 0.76 mg g^?1. Water washing removes all the water-soluble K of corn stalk and part of ion-exchangeable K enters the gas phase during pyrolysis of the washed sample. Water washing decreases the K release from 2.77 to 0.18 mg g^?1 at 1000 °C.     

Measurements of laminar burning velocities and onset of cellular instabilities of methane–hydrogen–air flames at elevated pressures and temperatures

An experimental study on laminar burning velocities and onset of cellular instabilities of the premixed methane–hydrogen–air flames was conducted in a constant volume combustion vessel at elevated pressures and temperatures. The unstretched laminar burning velocity and Markstein length were obtained over a wide range of hydrogen fractions. Besides, the effects of hydrogen addition, initial pressure and initial temperature on flame instabilities were analyzed. The results show that the unstretched flame propagation speed and the unstretched laminar burning velocity are increased with the increase of initial temperature and hydrogen fraction, and they are decreased with the increase of initial pressure. Early onset of cellular instability is presented and the critical radius and Markstein length are decreased with the increase of initial pressure, indicating the increase of hydrodynamic instability with the increase of initial pressure. Flame instability is insensitive to initial temperature compared to initial pressure. With the increase of hydrogen fraction, significant decrease in critical radius and Markstein length is presented, indicating the increase in both diffusional-thermal and hydrodynamic instabilities as hydrogen fraction is increased.     

Numerical and Experimental Modelling of Gas Flow and Heat Transfer in the Air Gap of an Electric Machine

This work deals with the cooling of high-speed electric machines, such as motors and generators, through an air gap. It consists of numerical and experimental modeling of gas flow and heat transfer in an annular channel. Velocity and temperature profiles are modeled in the air gap of a high-speed test machine. Friction and heat transfer coefficients are presented in a large velocity range. The goals are reached acceptably using numerical and experimental research. The velocity field by the numerical method does not match in every respect the estimated flow mode. The absence of secondary Taylor vortices is evident when using time averaged numerical simulation.     

Synthesis and characterization of Zr-promoted Ni-Co bimetallic catalyst supported OMC and investigation of its catalytic performance in steam reforming of ethanol

This article presents simple method for the OMC-6%Ni-6%Co (ordered mesoporous carbon containing Ni and Co metallic nanoparticles) catalyst synthesis with high surface area and more proper bimetallic nanoparticle dispersion; prepared successfully by soft template hydrothermal method and different zirconium loadings (0.5, 1, 2 wt %) accomplished by impregnation method, which was known as a desired method for the metal dispersion. The catalysts with/without promoter, were characterized by XRD, FTIR and N₂ adsorption-desorption isotherms, FESEM, EDS, EDS mapping, HRTEM and TPR techniques and investigated in steam reforming of ethanol (SRE) at 250–400 °C. XRD and BET results indicated that zirconium addition more than 0.5% wt, decreased the average mesopore diameter of catalysts, total pore volume and particles size. Also, it was stated that Ni²⁺ and Co²⁺ were caught by the RF/F127 network and further reduced into metallic Ni and Co nanoparticles during the carbonization. The Ni and Co nanoparticles were well-dispersed in the OMC walls. FTIR spectroscopy revealed that F127 left the structure and formed the porous structure. TPR analysis of OMC-6%Ni-6%Co/2%Zr sample, indicated that the sample is reduced easily at low temperatures. FESEM and HRTEM images showed that carbon was precipitated in the CNT form on spent catalyst samples surfaces and confirmed the position of Ni and Co bimetallic nanoparticles on the CNTs tip in the OMC-6%Ni-6%Co/2%Zr sample. 2% Zr-promoted bimetallic catalyst revealed appropriate catalytic performance for SRE, such as high activity, hydrogen yield and proper stability due to the synergistic catalysis of cobalt and nickel. Also, effective factors, such as H₂O/EtOH molar ratio and gas hourly space velocity (GHSV) were investigated on the OMC-6%Ni-6%Co/2%Zr catalyst sample.     

A wide range kinetic modeling study of pyrolysis and oxidation of methyl butanoate and methyl decanoate – Note II: Lumped kinetic model of decomposition and combustion of methyl esters up to methyl decanoate

The aim of this work is to develop and discuss a lumped kinetic model to simulate the pyrolysis and combustion behavior of methyl decanoate. Validation of the lumped kinetic model of methyl decanoate in a very wide range of conditions, with temperature ranging from 500 to more than 2000 K, pressures up to 16 bar and equivalent ratios from lean to pyrolysis conditions, proved that, despite the drastic simplifications, the model can properly reproduce the experimental measurements in pyrolysis as well as in an oxidation environment, in both the low temperature regime and in flame conditions. This model is an extension of the lumped model of methyl butanoate developed and discussed in the first part of this work [1]. Thus, the lumped kinetic model of methyl butanoate and methyl decanoate is also quite simply applied to simulating the combustion behavior of intermediate methyl esters, by using the lever rule between the two reference components. The overall agreement with experimental measurements is very encouraging and lays the basis for the extension to the lumped kinetic scheme to soy and rapeseed biodiesel fuels.     

Experimental and modeling study of performance and emissions of SI engine fueled by natural gas–hydrogen mixtures

Based on CFD software and reaction kinetics software, multi-dimensional CFD Model coupled with detail reaction kinetics is built to study the combustion process in H₂/CNG Engine. Detail reaction mechanism is used to simulate the chemistry of combustion and a combustion model considering the turbulent mixing effects was also applied. To reduce the computation time, the coupled software is reprogrammed to have the function of parallel computing and the revised software is computed in a Massively Parallel Processor. The model is validated using the experiment data from a modified diesel engine. The results show: cylinder pressure from simulation has a good agreement with experiment data and CO and NO_x emission is well predicted by the model in a wide range.     

Adoption of innovative heating systems—needs and attitudes of Swedish homeowners

Questionnaire surveys of Swedish homeowners of detached houses were carried out in 2004 and 2007 to understand their needs and attitudes towards attributes of innovative heating systems (IHSs) comprised of a bedrock heat pump, district heating, or a wood pellet boiler. In each occasion 1,500 homeowners were randomly selected. The response rate was 42% in 2004 and 48% in 2007. Results showed that the majority of the respondents were satisfied with their existing heating system and did not intend to install new systems. Economic factors and functional reliability were the most important factors in the respondents’ choices of heating system, while environmental factors were of lower importance. Among the IHSs, respondents had the most favorable attitude towards bedrock heat pumps followed by district heating and pellet boilers. But the attitude was more favorable towards electric boilers than for pellet boilers. The least favorable attitude was towards oil boilers. Between 2004 and 2007, there was a positive change in respondents’ attitude towards IHSs and electric boilers, and a negative change in attitude towards resistance heaters and oil boilers.     

Hydrodynamic and Heat Transfer Characteristics of Magnetofluidized Beds

ＨｙｄｒｏｄｙｎａｍｉｃａｎｄＨｅａｔＴｒａｎｓｆｅｒＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＭａｇｎｅｔｏｆｌｕｉｄｉｚｅｄＢｅｄｓＳ．Ｃ．Ｓａｘｅｎａ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＴｈｅＵｎｉｖｅｒｓｉｔｙｏｆＩｌｌ...