Production of Ultra Clean Coal

Steel, Karen M.; Besida, J.; O’Donnell, T. A.; Wood, Donna J.

doi:10.1016/s0378-3820(01)00171-0

Cited by 101 publications

(25 citation statements)

References 5 publications

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“…However, the increase of HCl concentration in leaching experiments did not affect the ash content significantly. Similar result was also obtained by Steel et al [9]. They found that dissolution of mineral matter isolated from coal with HCl slightly increased as the increase of HCl concentration.…”

Section: Resultssupporting

confidence: 89%

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Low Rank Coal Pre-treatment to Increase Its Reactivity Towards Gasification with Biomass

et al. 2018

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Coal can be used to produce hydrogen through steam gasification process. Indonesia has abundant coal reserves and thus hydrogen production from coal is very attractive. However, steam gasification of coal usually requires high temperature due to its low volatile content. The use of catalyst, such as alkaline and alkaline earth metal (AAEM) may promote the hydrogen production. AAEM metal can be found in biomass and thus co-gasification of coal and biomass may become the attractive solution as the AAEM may volatilize during gasification and catalyze the coal when it attaches to the coal surface. However, the presence of silicate may decrease catalytic activity of the attached AAEM and thus it needs to be removed by deashing process. This research aims to determine the effect of the solution type, solution concentration, reaction temperature, and reaction time of coal deashing. The results showed that deashing process decreased the ash content of coal to some extent proved by the gravimetric analysis result. The decrease of ash content also affected to the surface morphology of the coal as some pores are formed and thus the surface area of coal increased slightly. The increase of surface area allows more AAEM to be attached to the coal surface so that the coal may become more reactive towards steam gasification.

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Section: Resultssupporting

confidence: 89%

“…Steel et al [9] proved that silica content in coal could be decreased by leaching method using acid solution. Leaching method is done by mixing coal with acid solution at a certain temperature and time.…”

Section: Introductionmentioning

confidence: 99%

Low Rank Coal Pre-treatment to Increase Its Reactivity Towards Gasification with Biomass

et al. 2018

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“…It is known that HF, which was originally used for removing impurities from coal, can react with almost every mineral in mineral ores, such as kaolinite, montmorillonite, and quartz. [16] The reaction between hectorite and HF is thought to be as follows: …”

Section: Resultsmentioning

confidence: 99%

Molecular Characteristics of Poly(N‐isopropylacrylamide) Separated from Nanocomposite Gels by Removal of Clay from the Polymer/Clay Network

Haraguchi

2010

Macromol. Rapid Commun.

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The extraordinary mechanical and swelling/deswelling properties of nanocomposite (NC) gels are attributed to their unique organic (polymer)/inorganic (clay) network structure. In this study, poly(N-isopropylacrylamide) (PNIPA) was successfully separated from an NC gel network by decomposing the clay (hectorite) using hydrofluoric acid (HF). A very low HF concentration (0.2 wt.-%) was adequate for the decomposition of the clay without causing any damage to PNIPA. The separated PNIPA had a high $\overline M _{\rm w}$ (=5.5 × 10(6) g · mol(-1) ). Also, $\overline M _{\rm w}$ was almost constant regardless of the clay concentration (C(clay) = 1-25 × 10(-2) mol · l(-1) ), even though the properties of the NC gel varied widely over this C(clay) range. Comparisons of NC gels, PNIPA, and SiO(2) -NC gels indicated that the clay platelets specifically play an important role in NC gels.

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“…Ultra clean coal (UCC) is defined as a very low ash coal (<1 wt%) with various potential uses such as carbon feedstock for the production of aromatic chemicals and materials instead of oil, carbon source for the silicon smelting industry, and for fabrication of carbon anodes to replace petroleum coke [4]. The main application of UCC, however, would be as a fuel for its use in advanced power generation technologies such as direct firing in gas turbines [5].…”

Section: Introductionmentioning

confidence: 99%

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

Rubiera

Arenillas

Arias

et al. 2003

Fuel

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The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new coal cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from coal either by physical or chemical methods can be annulled if poor coal combustibility characteristics are attained. In this work a high volatile bituminous coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the clean coal was reduced to 0.3%. The original and treated coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system.Comparison of the combustion behaviour and pollutant emissions of both coals was conducted in a drop tube furnace operating at 1000 °C. The results of this work indicate that the char obtained from the chemically treated coal presents very different structure, morphology and reactivity behaviour than the char from the original coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised coal.

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Production of Ultra Clean Coal

Cited by 101 publications

References 5 publications

Low Rank Coal Pre-treatment to Increase Its Reactivity Towards Gasification with Biomass

Low Rank Coal Pre-treatment to Increase Its Reactivity Towards Gasification with Biomass

Molecular Characteristics of Poly(N‐isopropylacrylamide) Separated from Nanocomposite Gels by Removal of Clay from the Polymer/Clay Network

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

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