Time-resolved particle temperature and mass loss measurements of a bituminous coal during devolatilization

1989 ◽  
Vol 78 (2) ◽  
pp. 223-236 ◽  
Author(s):  
Thomas H. Fletcher
Keyword(s):  
Mass Loss ◽  
Bituminous Coal ◽  
Particle Temperature ◽  
Time Resolved

scholarly journals Study on the washability by using float sink test and thermal decomposition of the Mogoin gol bituminous coal

2020 ◽  
pp. 31-37
Author(s):  
Shagjjav E ◽  
Ariunaa A ◽  
Serikjan Kh ◽  
Purevsuren B
Keyword(s):  
Thermal Decomposition ◽  
Mass Loss ◽  
Bituminous Coal ◽  
Chemical Processing ◽  
Thermal Behaviors ◽  
Ultimate Analysis ◽  
Coal Classification ◽  
Proximate And Ultimate Analysis ◽  
Coal Properties ◽  
Proximate And Ultimate Analyses

The Mogoin gol bituminous coal properties were determined by proximate and ultimate analysis and thermal behaviors performed using a HITACHI TG/DTA7300 thermogravimetry analyzer. Float sink test carried out by Russian standard GOST 4790-93. Results of the proximate and ultimate analyses showed that the coal has Vdaf=30.7%, Ad=10.6%, Cdaf=76.5% and Qdaf=7532 kcal/kg. According to the coal classification, the coal belongs to the J class of bimuminous coal. The rate of mass loss was maximum in the range 483°С. Yields and ash contents of the fraction were γб=49.9 and 5.6% respectively, when for the separation was used heavy liquid with 1.3g/cm3 density. In general, it can be concluded that the Mogoin gol coal belongs to the category of coals with very good washability. Therefore, it will be advantageous and economically viable to use coal concentrate with low-ash for further chemical processing. Могойн голын ордын нүүрсний халууны задралын болон баяжигдах шинж чанарын судалгаа Хураангуй: Дээд ангилалын чулуун нүүрс болох Могойн голын ордын нүүрсний шинж чанарыг техникийн болон элементийн шинжилгээгээр, халуун, дулаан тэсвэрлэх чанарыг термогравиметр HITACHI TG/DTA7300 маркийн багажийн тусламжтайгаар, нүүрсний баяжигдах шинж чанарыг хүнд шингэний ГОСТ 4790-93 стандарт аргаар тодорхойллоо. Нүүрсний техникийн болон элементийн шинжилгээний үр дүнгүүдээс Ж маркийн чулуун нүүрс болохыг баталж байна. Жингийн алдагдлын хурд ДТГ 483°С-ын температурын мужид хамгийн их байв. Хүнд шингэний нягтыг ихэсгэх тутам баяжмалын үнс болон гарц аажмаар ихэсгэх хандлагатай бөгөөд δ=1.3 г/см3 нягттай хүнд шингэнд нүүрсийг баяжуулбал, үнс бага Aб а=5.6%, гарц өндөртэй γб=49.9% баяжмал гарган авах боломж. Иймд бага үнстэй нүүрсний баяжмалыг цаашид гүн боловсруулалтын чиглэлээр ашиглахад давуу талтай, эдийн засгийн ач холбогдолтой байх болно. Түлхүүр үг: нүүрс, термогравиметр, жингийн алдагдал, баяжуулалт, баяжмал, хөвсөн/ живсэн фракц

Time-resolved weight loss kinetics for the rapid devolatilization of a bituminous coal

1982 ◽  
Vol 19 (1) ◽  
pp. 1151-1157 ◽  
Author(s):  
Stephen Niksa ◽  
W.B. Russel ◽  
D.A. Saville
Keyword(s):  
Weight Loss ◽  
Bituminous Coal ◽  
Time Resolved

scholarly journals Erosion Mechanism of a Cavitating Jet on Groove Roughness

Fluids ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Nobuyuki Fujisawa ◽  
Takayuki Yamagata ◽  
Ryotaro Seki ◽  
Motofumi Ohki
Keyword(s):  
Mass Loss ◽  
Cavitation Bubble ◽  
Intensity Fluctuation ◽  
Observation Time ◽  
Time Resolved ◽  
Focusing Effect ◽  
Erosion Mechanism ◽  
Impulsive Forces ◽  
Flow Visualizations ◽  
Cavitating Jet

The erosion behavior of a cavitating jet on groove roughness was investigated experimentally using mass-loss characteristics, scanning electron microscopy (SEM) observation, time-resolved shadowgraph, and schlieren flow visualizations. The wall morphology of the cavitating-jet erosion on the groove roughness indicated an increased mass loss, which was highly increased along the groove rather than across the groove. Furthermore, increased erosion pits were observed on the groove bottom along the grooves. The shadowgraph imaging of the cavitating jet on the rough wall showed noncircular cavitation bubble distributions along and across the grooves, which corresponds to the increased number of cavitation bubbles along the grooves and the decreased number of bubbles across the grooves. This result is consistent with the erosion morphology of the groove roughness. Schlieren imaging indicated that the frequency and intensity fluctuation of the shockwave formation did not change significantly on the groove roughness along and across the grooves. The findings in the study show that the increased erosion mechanism on groove roughness is caused by the increased number of impulsive forces and the shockwave focusing effect on the groove bottom.

Effect of Nanoscale Species on the Behavior of Polymer Nanocomposites Subjected to Laser Pulse Heating

2012 ◽  
Vol 1519 ◽  
Author(s):  
Stephen F. Bartolucci ◽  
Jeffrey Warrender ◽  
Karen Supan ◽  
Jeffery Wiggins ◽  
Lawrence LaBeaud
Keyword(s):  
Carbon Nanotube ◽  
Mass Loss ◽  
Polymer Nanocomposites ◽  
Surface Characterization ◽  
Single Pulse ◽  
Heating Rates ◽  
Time Resolved ◽  
Nanotube Composites ◽  
Laser Pulse Heating ◽  
Multiple Pulses

ABSTRACTPolymers and polymer nanocomposites have been studied under conditions of extremely high heating rates. Traditionally, these materials have been examined by the flammability research community using methods which have heating rates on the order of 10 degrees C/min. In this study, we have examined how polypropylene-nanoclay (montmorillonite) and polypropylene-carbon nanotube nanocomposites behave subjected to heating rates on the order of one million degrees C/min when irradiated with a 1064 nm Nd-YAG variable pulse millisecond laser. Time-resolved temperature data and mass loss data was collected for each sample as well as post-mortem surface characterization using spectroscopy and electron microscopy. The analysis shows that the nanospecies are effective in providing a protective barrier that decreases the amount of degradation and mass loss to the underlying polymer material. The effect is clearly seen after irradiating with a single pulse and multiple pulses. A comparison between the performance of the nanoclay and carbon nanotube composites is given.

scholarly journals Combustion Characterisation of Bituminous Coal and Pinus Sawdust Blends by Use of Thermo-Gravimetric Analysis

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7547
Author(s):  
Garikai T. Marangwanda ◽  
Daniel M. Madyira ◽  
Patrick G. Ndungu ◽  
Chido H. Chihobo
Keyword(s):  
Mass Loss ◽  
Power Plants ◽  
Bituminous Coal ◽  
Synergistic Effects ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Maximum Increase ◽  
Fuel Blends ◽  
Fuel Blending

The cocombustion of coal and pinus sawdust waste is an economically viable and sustainable option for increasing the share of biomass in energy production. This technology also has the potential to reduce the emission of greenhouse gases from existing coal fired power plants. The thermal synergistic effects of cocombusting Hwange bituminous coal (HC) with Pinus sawdust (PS) were thus investigated using thermogravimetric analysis. Fuel blending mass ratios of 100HC, 90HC10PS, 80HC20PS, 70HC30PS, and 100PS under an oxidative atmosphere at three different heating rates of 5, 12.5, and 20 °C/min were used for the experimental setup. Zero to negative synergy was generally observed for the mass loss curves (TG) at different blending ratios. Generally positive synergy was observed with relation to rate of mass loss curves (DTG) for the 80HC20PS and 70HC30PS fuel blends only. The ignition index increased with blending ratio by an average of 42.86%, whilst the burnout index showed a maximum increase of 14.6% at 20 °C/min. However, the combustion index representative of stability showed a decreasing trend generally for all the heating rates. No combustion index produced a linear variation with temperature, though upon evaluation, an optimum mass ratio of 20% pinus sawdust was suggested. The chosen optimum blending ratio demonstrated increased ignition and burnout indexes whilst maintaining the stability of combustion at a reasonable range.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

Water accumulation as a function of temperature on specimens in an electron microscope cold stage

1986 ◽  
Vol 44 ◽  
pp. 114-115 ◽  
Author(s):  
M.K. Lamvik ◽  
D.A. Kopf ◽  
S.D. Davilla ◽  
J.D. Robertson
Keyword(s):  
Electron Microscope ◽  
Mass Loss ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Cold Stage ◽  
Water Accumulation ◽  
Better Than

Last year we reported1 that there is a striking reduction in the rate of mass loss when a specimen is observed at liquid helium temperature. It is important to determine whether liquid helium temperature is significantly better than liquid nitrogen temperature. This requires a good understanding of mass loss effects in cold stages around 100K.

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