Infrared ray is an electromagnetic wave having a wave length at range from 0.76μm to 1000μm longer than the visible ray. The theory of radiation energy propagation can be considered from electromagnetic wave theory and quantum mechanics. To achieve high efficiency heat effects of infrared radiant are made to accommodate radiation characteristic of radiant and absorption characteristic of matter heated. Consequently, infrared radiation and its utilization are described for kind of infrared radiant, measurement of infrared radiation spectrum, evaluation and utilization of infrared radiants.
Gas or kerosine is vacuum-combusted and the combustion gas is adjusted to a proper temperature to heat the radiation tube which radiates far infrared rays. The rays are directed to the object area by reflectors to heat at high efficiency. Neither electric power, steam, nor hot water is used as the heat source. For heating and drying, far infrared rays are much superior. By selecting proper wavelength, far infrared rays offers comfortable circumstance for good health and amenity.
Infrared spectrum is generally divided into two distinct regions; near infrared with wavelengths shorter than about 4μm and far infrared with wavelengths greater than about 4μm. In this paper, thermal properties of infrared radiation and effectiveness of far infrared radiation for space heating are investigeted. The thermal properties of infrared radiation are as follows: 1) For human skin and clothing fabrics, the reflection of radiation is low in the wavelength region over 2μm while the radiation emitted by a radiant space heater exists almost in this region. 2) For the skin, the transmission of near infrared radiation is higher than that of far infrared radiation. 3) The thermal sensation for each wavelength is not different in the wavelength region over 2μm. It is generally accepted that space heaters emitting far infrared radiation make comfortable environment. But the investigation of infrared radiation properties shows that far infrared radiation itself is not specially effective for space heating. On the other hand, far infrared radiant heaters make comfortable environment because they are low temperature radiant heaters which make uniform and moderate radiant environment without any excessive wind that makes human body feel uncomfortable.
With the progress of engineering of far infrared radiation (radiation with the wavelength range of 4μm to 1mm), various types of far infrared radiators have been used widely to many applicable fields. Types and kinds of radiative materials, emissivity, factors influencing emissive characteristics, and so on are described, especially when they are applied to radiators as a kind of combustion apparatus. Results about metals, nonmetalic elements, ceramics are summarized and in addition, the effect of water vapour and carbon dioxide in a flame, is also discussed.
The recycle solvents from two stage liquefaction of Yallourn and Taiheiyo coals were analyzed to verify the effect of solvent quality on the promotion of coal conversion observed in the experiments using red mud and NiMo/Al2O3 at the first stage. The start-up solvent, tetralin decreased in amount progressively with cycle number, and coal-derived components including nondistillable bottom increased gradually in the recycle solvent. GC analyses revealed that hydroaromatics accumulated over successive passes as well as polycondensed aromatics, such as phenanthrene, fluoranthene and pyrene. Accordingly, the changes in composition seem to enhance hydrogen donor ability for solvents in the last several passes, which accounts for the restriction of n-paraffin accumulation into the recycle solvent produced from Taiheiyo coal. Moreover, it was shown under the experimental conditions that there was no distinct difference in the properties of bottoms from Yallourn and Taiheiyo coals. This is due to the promotion of hydrogenation and deoxygenation reaction in addition to the improvement of solvent quality.
Pulverized Pittston and Optimum coals were pyrolysed at 700-1200 K in a free fall reactor. To characterize the coal structure, Pittston coal and its char samples were solubilized by reductive alkylation method and the original and ethylated samples were extracted with pyridine. The molecular weight distribution of the soluble samples was measured by gel permeation chromatography. The rigidity of the coal and char molecule was estimated from the solvent-induced swelling ratio in pyridine. The pyridine soluble (PS) yield depends on the pyrolysis temperature, and reaches the maximum at 800K. However, no significant changes are observed in both the molecular weight and the H/C atomic ratio. The number-average molecular weight of PS is in the range of 400-600. The PS yield increases to 60-80 wt% after the ethylation of coal and char. The molecular weight of PS in ethylated samples distributes over the range of 100-50000 (alkyl-free basis). The number-average molecular weight has the minimum for the ethylated char obtained at 800K. Above 900 K, the PS yield lowers, with the decreasing molecular weight. The experimental results are examined on the basis of the two models assuming that coal consists of a covalently crosslinked macromolecule network trapping smaller molecules, or that coal is a mixture of molecules which has a continuous molecular weight distribution. Under the present experimental conditions, the latter model is better explains the relationship between the molecular weight distribution and the frac-tion of solute.
Development of hot coal gas desulfurization process (dry process) is necessary to get high thermal efficiency in Integrated Coal Gasification Power Generation System. Fixed bed desulfurization process using Fe2O3 sorbents have been researched and developed at Yokosuka Research Laboratory. In this study, pellet type Fe2O3 sorbents were prepared and characteristics of sorbents for H2S sorption was studied using packed bed reactor. The following results were obtained. (1) Characteristics for H2S sorption was independent of support materials (SiO2, SiO2-Al2O3, Al2O3). Fe2O3 content must be below 20wt% to keep off crack caused by carbon deposition. (2) H2S sorption capacity (Fe2O3-SiO2, Fe2O3-SiO2-Al2O3) was 2.5×10-3mol/g. All of Fe2O3 contained in sorbents were converted to FeS. (3) Apparent activation energy was 11kJ/mol. H2S sorption rate at 2.1MPa was two times as fast as the rate at atmospheric pressure.
The hydrogen transferring liquefactions of Morwell brown coals (different lots) and two subbituminous coals (Taiheiyo and Wandoan) were comparatively examined using tetrahydrofluoranthene (4HFL) as a donor solvent at 450°C and solvent/coal ratio of 1.5/1 under low hydrogen or nitrogen pressure. Effects of low hydrogen pressure on the liquefaction yields depend on the coal species. The liquefaction reactivities of two Morwell coals of different lots were compared in terms of the products distribution, the efficiency of hydrogen consumption and the reaction rates through the structural analyses of products at the initial stage. Morwell-III coal gave a higher oil yield than Morwell-II coal of higher oxygen content. Asphaltenes derived from two Morwell coals showed much difference in H/C, fa and the number of aromatic ring at the initial stage of liquefaction, reflecting their different liquefaction reactivities. On the basis of the results mentioned above, the relationship between coal structures (especially the products at the initial stage) and liquefaction mechanism under low hydrogen pressure is discussed.