Offsetting particulate matter emissions has become a critical global aim as there are concerted efforts to deal with environmental and energy poverty challenges.This study consists of investigations of computing emiss...Offsetting particulate matter emissions has become a critical global aim as there are concerted efforts to deal with environmental and energy poverty challenges.This study consists of investigations of computing emissions of particulate matter from biomass fuels in various atmospheres and temperatures.The laboratory setup included a fixed bed electric reactor and a particulate matter(PM)measuring machine interfaced with the flue gas from the fixed bed reactor combustion chamber.The experiments were conducted at seven different temperatures(600℃-1200℃)and six incremental oxygen concentrations(21%-100%).Five biomass types were studied;A-cornstalk,B-wood,C-wheat straw,D-Rice husk,E-Peanut shell,each pulverized to a size of approximately 75 microns.The study shows that PM emitted during char combustion is consistently higher than that emitted during the de-volatilization.During de-volatilization,increase in temperature leads to linear decrease in PM emission between atmospheres of 21%O_(2)to 50%O_(2),thereafter,between 70%O_(2)to 100%O_(2);increase in temperature leads to a rise in PM emission.The average PM formation from all the five considered biomass is relatively comparable however,with differing atmospheres and temperatures,the fibrous and low-density biomass forms more PM.During char combustion,the study shows that at oxygen levels of 21%,70%,90%and 100%,increase in temperature leads to increased PM emission.The increase in oxygen concentration and temperature increases the rate of combustion hence diminishing the time of combustion.展开更多
Typical biomass torrefaction is a mild pyrolysis process under conditions of ordinary pressure,low temperature(200–300°C)and inert atmosphere.Torrefaction is considered to be a competitive technology for biomass...Typical biomass torrefaction is a mild pyrolysis process under conditions of ordinary pressure,low temperature(200–300°C)and inert atmosphere.Torrefaction is considered to be a competitive technology for biomass pretreatment,but its impacts on the emissions of particulate matter from biomass combustion are worthy of further study.In this paper,three kinds of biomass,i.e.,bagasse,wheat straw and sawdust were selected for torrefaction pretreatment and the impacts of torrefaction on the emission characteristics of PM_(10) from biomass combustion were investigated.The combustion experiments were carried out on a drop tube furnace.The combustion-generated particulate and bulk ash samples were collected and subjected to analyses by various techniques.The results show that torrefaction tends to result in a reduction of PM_(1)(particulates with an aerodynamic diameter less than 1μm)emissions from combustion,but the extent of reduction is dependent on biomass type.The reduction of PM_(1) from the combustion of torrefied biomass is mainly because that the torrefaction process removes some Cl and S from the biomass,thereby suppressing the release of alkali metals and the emissions of PM_(1) during the combustion process.As for PM_(1–10)(particulates with an aerodynamic diameter within 1–10μm),its emissions from combustion of torrefied biomasses are consistently reduced,compared with their untreated counterparts.This observation is primarily accounted for the enhanced particle coalescence/agglomeration in combustion of torrefied biomasses,which reduces the emissions of PM_(1–10).展开更多
We propose a numerical methodology for the simultaneous numerical simulation of four states of matter:gas,liquid,elastoplastic solids,and plasma.The distinct,interacting physical processes are described by a combinati...We propose a numerical methodology for the simultaneous numerical simulation of four states of matter:gas,liquid,elastoplastic solids,and plasma.The distinct,interacting physical processes are described by a combination of compressible,inert,and reactive forms of the Euler equations,multi-phase equations,elastoplastic equations,and resistive MHD equations.Combinations of systems of equations are usually solved by coupling finite element for solid modelling and CFD models for fluid modelling or including material effects through boundary conditions rather than full material discretisation.Our simultaneous solution methodology lies on the recasting of all the equations in the same,hyperbolic form allowing their solution on the same grid with the same finite volume numerical schemes.We use a combination of sharp-and diffuse-interface methods to track or capture material interfaces,depending on the application.The communication between the distinct systems of equations(i.e.,materials separated by sharp interfaces)is facilitated by means of mixed-material Riemann solvers at the boundaries of the systems,which represent physical material boundaries.To this end,we derive approximate mixed-material Riemann solvers for each pair of the above models based on characteristic equations.To demonstrate the applicability of the new methodology,we consider a case study,where we investigate the possibility of ignition of a combustible gas that lies over a liquid in a metal container that is struck by a plasma arc akin to a lightning strike.We study the effect of the metal container material and its conductivity on the ignition of the combustible gas,as well as the effects of an additional dielectric coating,the sensitivity of the gas,and differences between scenarios with sealed and pre-damaged metal surfaces.展开更多
This study focused on the contents of the air particulate matter pollution in two districts of Ulaanbaatar and determined the chemical composition of air borne samples and the source of those particles. Samples of fin...This study focused on the contents of the air particulate matter pollution in two districts of Ulaanbaatar and determined the chemical composition of air borne samples and the source of those particles. Samples of fine and coarse fractions of PM were collected using a “Gent” stacked filter unit in two fractions of 0 - 2.2 μm and 2.2 - 10 μm sizes in two semi-residential areas from September 2012 to August 2013. This paper points out that fine and coarse concentration varied seasonally with meteorological changes. In sampling site 3, Zuun Ail (Figure 1) combustion generators generate the majority of pollution around 50.6% of household waste furnace to create high-temperature combustion of 21.6%. However, this net contributes to soil contamination near the lower value (5%) that arises around the vacuum environment in substantial amounts (14%), where is open around the buildings and residential areas, and the soil is considered to be due to the construction. But the data point to the highway in the distance, where is 9% of contamination of all vehicles’ smoke, and exhaust is similar to the data collected in Ulaanbaatar. According to analysis of samples of Nuclear Research Center (NRC) sampling site 2, it shows burning source of Particulate Matter 2.5 pollution in the air is around 25.5% of household waste furnace to create high-temperature product of combustion. But here the very high net contribution to the pollution of soil, is 31.6%. Today’s emerging dust is around 15.2%, showing that motor vehicle pollution causes 19.7%. Since the analysis was done on a sample-by-sample basis, it is possible to estimate the daily contributions of pollution sources and provide useful information based on a limited number of samples in order to address air quality management issues in Ulaanbaatar.展开更多
基金Authors are grateful to Quanzhou Tongjiang Scholar Special Fund for financial support through Grant No.(600005-Z17X0234)Quanzhou Science and Technology Bureau for financial support through Grant No.(2018Z010)+2 种基金Huaqiao University through Grant No.(17BS201)the Fujian ProvincialDepartment of Science and Technology for financial support through Grant(2018J05121)Authors are also grateful for financial support from the Fujian Provincial Department of Science and Technology through Grant Nos.2021I0014 and 2018J05121.
文摘Offsetting particulate matter emissions has become a critical global aim as there are concerted efforts to deal with environmental and energy poverty challenges.This study consists of investigations of computing emissions of particulate matter from biomass fuels in various atmospheres and temperatures.The laboratory setup included a fixed bed electric reactor and a particulate matter(PM)measuring machine interfaced with the flue gas from the fixed bed reactor combustion chamber.The experiments were conducted at seven different temperatures(600℃-1200℃)and six incremental oxygen concentrations(21%-100%).Five biomass types were studied;A-cornstalk,B-wood,C-wheat straw,D-Rice husk,E-Peanut shell,each pulverized to a size of approximately 75 microns.The study shows that PM emitted during char combustion is consistently higher than that emitted during the de-volatilization.During de-volatilization,increase in temperature leads to linear decrease in PM emission between atmospheres of 21%O_(2)to 50%O_(2),thereafter,between 70%O_(2)to 100%O_(2);increase in temperature leads to a rise in PM emission.The average PM formation from all the five considered biomass is relatively comparable however,with differing atmospheres and temperatures,the fibrous and low-density biomass forms more PM.During char combustion,the study shows that at oxygen levels of 21%,70%,90%and 100%,increase in temperature leads to increased PM emission.The increase in oxygen concentration and temperature increases the rate of combustion hence diminishing the time of combustion.
基金funded by the National Key Research and Development Program of China(No.2016YFB0600601).
文摘Typical biomass torrefaction is a mild pyrolysis process under conditions of ordinary pressure,low temperature(200–300°C)and inert atmosphere.Torrefaction is considered to be a competitive technology for biomass pretreatment,but its impacts on the emissions of particulate matter from biomass combustion are worthy of further study.In this paper,three kinds of biomass,i.e.,bagasse,wheat straw and sawdust were selected for torrefaction pretreatment and the impacts of torrefaction on the emission characteristics of PM_(10) from biomass combustion were investigated.The combustion experiments were carried out on a drop tube furnace.The combustion-generated particulate and bulk ash samples were collected and subjected to analyses by various techniques.The results show that torrefaction tends to result in a reduction of PM_(1)(particulates with an aerodynamic diameter less than 1μm)emissions from combustion,but the extent of reduction is dependent on biomass type.The reduction of PM_(1) from the combustion of torrefied biomass is mainly because that the torrefaction process removes some Cl and S from the biomass,thereby suppressing the release of alkali metals and the emissions of PM_(1) during the combustion process.As for PM_(1–10)(particulates with an aerodynamic diameter within 1–10μm),its emissions from combustion of torrefied biomasses are consistently reduced,compared with their untreated counterparts.This observation is primarily accounted for the enhanced particle coalescence/agglomeration in combustion of torrefied biomasses,which reduces the emissions of PM_(1–10).
基金This work was supported by Jaguar Land Rover and the UK-EPSRC Grant EP/K014188/1 as part of the jointly funded Programme for Simulation Innovation and Boeing Research&Technology(BR&T)Grant SSOW-BRT-L0516-0569.
文摘We propose a numerical methodology for the simultaneous numerical simulation of four states of matter:gas,liquid,elastoplastic solids,and plasma.The distinct,interacting physical processes are described by a combination of compressible,inert,and reactive forms of the Euler equations,multi-phase equations,elastoplastic equations,and resistive MHD equations.Combinations of systems of equations are usually solved by coupling finite element for solid modelling and CFD models for fluid modelling or including material effects through boundary conditions rather than full material discretisation.Our simultaneous solution methodology lies on the recasting of all the equations in the same,hyperbolic form allowing their solution on the same grid with the same finite volume numerical schemes.We use a combination of sharp-and diffuse-interface methods to track or capture material interfaces,depending on the application.The communication between the distinct systems of equations(i.e.,materials separated by sharp interfaces)is facilitated by means of mixed-material Riemann solvers at the boundaries of the systems,which represent physical material boundaries.To this end,we derive approximate mixed-material Riemann solvers for each pair of the above models based on characteristic equations.To demonstrate the applicability of the new methodology,we consider a case study,where we investigate the possibility of ignition of a combustible gas that lies over a liquid in a metal container that is struck by a plasma arc akin to a lightning strike.We study the effect of the metal container material and its conductivity on the ignition of the combustible gas,as well as the effects of an additional dielectric coating,the sensitivity of the gas,and differences between scenarios with sealed and pre-damaged metal surfaces.
文摘This study focused on the contents of the air particulate matter pollution in two districts of Ulaanbaatar and determined the chemical composition of air borne samples and the source of those particles. Samples of fine and coarse fractions of PM were collected using a “Gent” stacked filter unit in two fractions of 0 - 2.2 μm and 2.2 - 10 μm sizes in two semi-residential areas from September 2012 to August 2013. This paper points out that fine and coarse concentration varied seasonally with meteorological changes. In sampling site 3, Zuun Ail (Figure 1) combustion generators generate the majority of pollution around 50.6% of household waste furnace to create high-temperature combustion of 21.6%. However, this net contributes to soil contamination near the lower value (5%) that arises around the vacuum environment in substantial amounts (14%), where is open around the buildings and residential areas, and the soil is considered to be due to the construction. But the data point to the highway in the distance, where is 9% of contamination of all vehicles’ smoke, and exhaust is similar to the data collected in Ulaanbaatar. According to analysis of samples of Nuclear Research Center (NRC) sampling site 2, it shows burning source of Particulate Matter 2.5 pollution in the air is around 25.5% of household waste furnace to create high-temperature product of combustion. But here the very high net contribution to the pollution of soil, is 31.6%. Today’s emerging dust is around 15.2%, showing that motor vehicle pollution causes 19.7%. Since the analysis was done on a sample-by-sample basis, it is possible to estimate the daily contributions of pollution sources and provide useful information based on a limited number of samples in order to address air quality management issues in Ulaanbaatar.
