Effect of pH on the removal of pyritic sulfur from coal by oxydesulfurization

Joshi, J. B.; Shah, Y.T.; Albal, R.S.; Ritz, Hadas

doi:10.1021/i200019a010

Cited by 7 publications

(2 citation statements)

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“…They have observed that the rate of reaction is second order in pyritic sulfur based on the continuous reaction model as reported by Slagle et al (1980). Joshi et al (1982) have studied the effect of pH on the removal of pyritic sulfur from coal by oxydesulfurization. Their observations indicate that the rate of pyrite oxidation is at a minimum at nearly neutral conditions.…”

Section: Chowdhury Andmentioning

confidence: 96%

“…Under otherwise identical conditions, the rate of pyrite oxidation is reported to be greater in basic pH than in acidic pH. These enhancements in the rate of pyrite oxidation have been explained on the basis of electrochemical reactions [Joshi et al (1982)]. Joshi et al (1983) have reported the effect of particle size in the air/water chemical coal cleaning.…”

Section: Chowdhury Andmentioning

confidence: 99%

See 1 more Smart Citation

Wet Air Oxidation

Mishra¹,

Mahajani²,

Joshi³

1995

Ind. Eng. Chem. Res.

711

482

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Section: Chowdhury Andmentioning

confidence: 96%

Section: Chowdhury Andmentioning

confidence: 99%

Wet Air Oxidation

Mishra¹,

Mahajani²,

Joshi³

1995

Ind. Eng. Chem. Res.

711

482

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Effluent treatment for alcohol distillery: Thermal pretreatment with energy recovery

1989

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Stillage from cane molasses based atcohol distillery was thermally treated at 160 to 250°C at high pressure and in the absence of air. A solid charred residue was precipitated that was easily separated by gravity filtration from a liquid suitable for anaerobic digestion or wet oxidation. The charred residue was comparable with typical lignite coal in terms of carbon content and calorific value. Effects of temperature and pH on COD reduction, biodegradability, and filterability were studied. INTRODUCTIONProduction of ethyl alcohol in distilleries based on cane sugar molasses is a very large industry in tropical areas such as Asia and South America. The world's total production of alcohol from cane molasses is more than 13Mm3/yr. The molasses is diluted and fermented with yeast and the resultant liquid, containing 643% alcohol by volume, is distilled to recover alcohol. The dealcoholized aqueous stream coming out of distillation unit is a dark brown, highly organic effluent known as stillage or vinase, and is about 12 to 15 times by volume of the product alcohol. The stillage is one of the most complex, troublesome, and strongest organic industrial effluents. It has a COD value of 100 kg/m3 and BOD of 50 kg/m3. It has been estimated that the BOD load of the stillage discharged by a typical distillery with a capacity of 30 m3/d alcohol, is equivalent to the BOD load of sewage stream of a city having a population of 500,000. Thus, the alcohol distillery industry has posed a serious pollution problem and extensive research and development work is being carried out all over the world. Due to the high concentration of organic load (COD) in the distillery stillage, it is a potential source of renewable energy. A countrywide cane-based alcohol production, along with energy equivalents is given in Table 1 [I].Since most of the advanced countries produce 90% of the world's beet sugar and only 10% of world's cane sugar concentrations and hence, is a more difficult waste for treatment in comparison with the beet-based stillage. Further, sulphur dioxide is used for bleaching in the cane sugar process, which results in a large concentration of sulphate ions in the stillage, making the stream more difficult to treat biologically. Therefore, dilution before the treatment has been recommended [3]. It was thought desirable to undertake the treatment of stillage from sugar cane molasses with a novel approach for energy recovery.The proposed method results in some dilution without adding any external water. Another attractive feature of the proposed method is that there is a drastic reduction in the COD value from initial 100 kg/m' to 50 k g h ' in less than two hours. If this process can be implemented on plant scale, it will help in controlling the distillery environmental pollution and foul odor of the fermenting stillage for kilometers around. Also, contamination of surface and ground water by seepage of stillage can be prevented.At present, stillage treatments are proposed by ihree different routes: concentration followed by inc...

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