摘要:

While suggesting an integrated approach for utilization of inferior low rank coals for power in India, the importance of low temperature carbonization followed by retrieval of all value-based products has been stressed. It is further suggested that tar, obtained in the process, could be hydrogenated and fractionated in a central plant for conversion to hydrocarbons. High ash char, the principal product of pyrolysis, has been experimentally found to be amenable to beneficiation, yielding suitable fractions for power generation, briquetting, or blending. Experimental studies have shown that forest litters and agricultural wastes, containing significant proportions of spore, cuticle, and exine considered as precursors of hydrocarbon-generating coal macerals also yield large quantities of tar, ammonical liquor, and the principal product, char, which can be respectively utilized for the production of petroleum substitutes, value-based chemicals, and source material for blending, briquette making, and char-water slurries, opening up new avenues for fuel utilization and conservation.

ISSN:0090-8312    

DOI:10.1080/00908319950014506

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

In a new model of coal seam formation, advocating the allochthonous process, it has been suggested that the precursor of vitrain was deposited as chemical sediment in a dissolved state derived principally from cellulose segregated from wood tissues. Under acidic conditions, this sediment precipitated as humic acid and continued to float over the aqueous medium. Due to seasonal desiccation of the basin, the floated humic layer, free from contamination of argillaceous impurities, gradually descended and superimposed over the earlier-formed lithotypes. The precursors of durainous lithotypes, in contrast, composed principally of lignin-enriched residual plant cell walls, sticky hydrogen-rich plant ingredients, and agrillaceous dirts, were deposited in the basin as clastic sediments. With a fresh influxof chemical and clastic sediments, the horizontal deposition of basic infrastructures of lithotypes covering an extensive area was repeated, thereby developing the vertical height of the coal seam depicting alternate bands with characteristic affinity to argillaceous impurities.

ISSN:0090-8312    

DOI:10.1080/00908319950014515

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Turkey has a total hydropower potential of 433 GW that is equal to 1.2% of the total hydropower potential of the world and to 14% of European hydropower potential. Only 125 GW of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 34% of the economically usable potential of the country would be tapped. At the present, hydropower energy is an important energy source for Turkey due to its useful characteristics such as being renewable, clean, and less impactful on the environment, and a cheap and domestic energy source.

ISSN:0090-8312    

DOI:10.1080/00908319950014524

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Regeneration properties of sulfated dolomite and limestone samples were investi gated. Natural stones were first fully calcined at 1223 K in a gaseous atmosphere consisting of CO215 vol.% and dry air 85 vol.%; second, sulfation of the calcines was achieved by reacting them with a gaseous mixture consisting of CO215 vol.%, SO20.35 vol.%, and a balance of dry air at 1223 K; last, sulfated calcines were regenerated at 1373 K by a reductive decomposition process. During regeneration a 3:1 volumetric ratio of CO2/CO was maintained in the reducing gaseous atmosphere to minimize CaS formation. It has been found that for the five sulfation generation cycles the reactivity of the limestone and dolomite samples remained at acceptable levels. Since the repeated sulfation-regeneration steps caused an important change on the crystal lattice, as compared to the fresh stones, sorbent reactivity was also changed.

ISSN:0090-8312    

DOI:10.1080/00908319950014533

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

A heat pump and thermal energy storage unit were combined in an experimental setup to utilize solar energy and waste heat efficiently at low temperatures (10-50 C). The calcium chloride hexahydrate was used as the thermal energy storage medium and water was used as the working liquid between storage tank and collectors. The performance of the experimental setup at different heat source temperatures for space heating in a laboratory building in Trabzon, Turkey, were investigated both experimentally and theoretically. The fraction of the space heating load that was supplied by the solar-assisted system was determined as a function of collector area and storage volume from a developed numerical method and results were compared with experimental results.

ISSN:0090-8312    

DOI:10.1080/00908319950014542

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Mixtures of Ca(OH)2 and different siliceous materials such as fly ash, bentonite, silica fume, and diatomite were hydrated to produce reactive SO2 sorbents. It was observed that these sorbents showed a better reactivity toward SO2 than the Ca(OH)2 itself. This behavior is closely related to the pozzolanic nature of the hydrated sorbents and to the greater surface area. The reactivity of the sorbents was strongly influenced by the source of siliceous material and the hydration conditions. The total sulphation capacities of the sorbents were determined at 338 K with a synthetic gaseous mixture containing 5,000 ppm SO2 and 55% relative humidity. Depending on the chemical and physical properties of the sorbents, the SO2 captures ranged from 1.20 to 5.58 mmol SO2/g sorbent. The amount of SO2 capture increased with the increasing surface area of the sorbent. The utilization of Ca(OH)2 with SO2 improved significantly when Ca(OH)2 was hydrated with siliceous materi als first and later exposed to SO2.

ISSN:0090-8312    

DOI:10.1080/00908319950014551

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Two different catalysts (Na2CO3, Li2CO3) were impregnated into a low-rank lignite coke to investigate the effects of catalyst type at different reaction temperatures (600-700 C) on the rate of steam gasification in a fixed reactor. Total conversion sharply increases with increasing gasification time and with the use of Na2CO3 and Li2CO3. The catalytic activities under identical experimental conditions were found to be ranked as Na2CO3>Li2CO3. Activation energies and frequency factors of the catalytic reactions were deduced through a kinetic model and compared with noncatalytic steam gasification reactions. Catalytic reactions yielded much smaller values than those of the noncatalytic reactions. Furthermore, it is also observed that the conversion rate is primarily affected by the reaction temperature.

ISSN:0090-8312    

DOI:10.1080/00908319950014560

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The present study includes two main parts. The first describes hydrogen production from electrolysis water depending on the DC output current of the photovoltaic (PV) energy source. The second part presents the utilization of produced hydrogen to generate electric power. The design of a closed loop cycle for electrolyzer and fuel cell to produce hydrogen and generate electrical energy, respectively, depending on a renewable energy source, is considered. Five different types of electrolyzer and fuel cells are studied to depict the effect of these types with respect to the current, voltage, cell temperature, cell pressure, sizing, and the required number of modules to produce one cubic meter of hydrogen per one hour. According to the various types of electrolyzer and fuel cell, multi PV systems are designed to produce 10 m3/day of hydrogen. The daily PV solar energy consumption to produce 10 m3 of hydrogen gas is calculated. Also, I-V and P-V characteristics of PV arrays for different percentages of insolation for the selected isolated area (Aswan) are calculated. The results show that the first type of electrolyzer (conventional alkaline) is the most economical one to produce hydrogen gas at the lowest values of the electrical current and voltage. The first and the second types of the fuel cells (alkaline & polymer membrane) generate a higher value of electrical energy than the others.

ISSN:0090-8312    

DOI:10.1080/00908319950014579

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The electrochemical reduction of CO2 in tetraethylammonium perchlorate methanol electrolyte was investigated with a copper wire electrode at an extremely low temperature (-30 C). The main products from CO2 by the electrochemical reduction were methane, ethylene, carbon monoxide, and formic acid. Under the optimum experimental conditions, 28.1% faradaic efficiency methane, 7.2% ethylene, 67.8% carbon monoxide, and 23.2% formic acid were produced from CO2 by the electrochemical reduction. The maximum partial current densities for CO2 reduction and hydrocarbons were 4.5 and 1.6 mA cm-2 at 4.0 V vs SCE, respectively. At -30 C, the efficiency of hydrogen formation, being a competitive reaction against CO2 reduction, was suppressed to less than 10.1%.

ISSN:0090-8312    

DOI:10.1080/00908319950014588

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

This paper presents a modeling framework for estimating energy demand and CO2 emissions from process industries. The model has been used to project the same for four energy-intensive industries steel, cement, fertilizer, and aluminum in India, which account for nearly 50% of the energy consumed in the industrial sector.

ISSN:0090-8312    

DOI:10.1080/00908319950014597

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor