Effect of steam and sodium hydroxide for the production of hydrogen on gasification of dehydrochlorinated poly(vinyl chloride)

Kamo, Tohru; Takaoka, Kanji; Otomo, Junichiro; Takahashi, Hiroshi

doi:10.1016/j.fuel.2005.10.002

Cited by 20 publications

(21 citation statements)

References 17 publications

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“…Kamo et al 28 used alkali hydroxides to capture CO 2 and HCl while producing relatively pure hydrogen from a chlorine-containing waste plastic. The molten bed designed by Kamo et al 28 is ideal for generating hydrogen because the pressure is near atmospheric and there is an excess of alkali hydroxides. By using an excess of alkali hydroxides, Kamo et al 28 were able to maintain a molten bed, even though the gasifier temperature was below the melting point of sodium and potassium carbonate.…”

Section: Introductionmentioning

confidence: 99%

“…26,27 At the time that most of the original research on catalytic gasification was conducted, reducing CO 2 emission was not a driving force for the research, and it has not been until relatively recently that research has been published on molten beds of alkali hydroxides for in situ CO 2 capture. Kamo et al 28 used alkali hydroxides to capture CO 2 and HCl while producing relatively pure hydrogen from a chlorine-containing waste plastic. The molten bed designed by Kamo et al 28 is ideal for generating hydrogen because the pressure is near atmospheric and there is an excess of alkali hydroxides.…”

Section: Introductionmentioning

confidence: 99%

“…The gasifier was operated at moderate temperatures (600-900 C) and elevated pressures (2.1 MPa). In addition, on a per carbon basis, less alkali hydroxides and water vapour were sent to the gasifier than in the molten alkali hydroxide gasifier operated by Kamo et al 28 This means that we expect most of the alkali hydroxide to convert to alkali carbonates. In order to maintain the bed in a molten state, we used an equimolar mixture of LiOH, NaOH, and KOH.…”

Section: Introductionmentioning

confidence: 99%

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Molten catalytic coal gasification with in situ carbon and sulphur capture

Siefert

Shekhawat

Litster

et al. 2012

Energy Environ. Sci.

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A molten catalytic process has been demonstrated for converting coal into a synthesis gas consisting of roughly 20% methane and 80% hydrogen using alkali hydroxides as both catalysts and in situ CO 2 capture agents. Baselines studies were also conducted using no catalyst, weak capture agents (CaSiO 3 ) and strong in situ capture agent for acid gases (CaO). While a similar gas composition can be achieved using CaO rather than alkali hydroxides, the rate of syngas production is greater when using molten alkali hydroxides than when using CaO as the in situ capture agent for acid gases, such as HCl, H 2 S and CO 2 . Parametric studies were conducted to understand the effects of temperature, pressure, catalyst composition, steam flow rate and the ratio of coal to alkali hydroxide on the performance of the molten catalytic gasifier in terms of kinetics and syngas composition. To measure the amount and the rate of coal conversion, we have developed a method for quantifying the coal conversion as the reduction charge remaining, which is related to the chemical oxygen demand remaining in the coal. At temperatures between 800 C and 900 C, we measured first-order steam-coal gasification rates using sub-bituminous coal of 2 h À1 in a fixed bed reactor while capturing significant quantities of both H 2 S and CO 2 , and while also generating 20% methane plus ethane in the syngas on a dry volume basis.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molten catalytic coal gasification with in situ carbon and sulphur capture

Siefert

Shekhawat

Litster

et al. 2012

Energy Environ. Sci.

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“…This method uses NaOH for the reformation of organic matter to produce H 2 . Kamo et al [4] pyrolyzed dehydrochlorinated polyvinyl chloride (PVC) and activated carbon with NaOH and steam to generate H 2 and sodium carbonate (Na 2 CO 3 ). This process has CH 4 , ethane (C 2 H 6 ) and carbon dioxide (CO 2 ) as byproducts in minor percent.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Studies of Sodium Hydroxide and Carbon Monoxide Reaction

2012

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Abstract:We have studied the effect of ball milling on alumina mixed nickel, magnetite and Raney nickel on the reaction: 2NaOH(s) + CO (g) = Na 2 CO 3 (s) + H 2 (g) and determined the optimum particle size for the catalysts. The best performance was shown by a 2 h ball milled Raney nickel with average crystallite size of 209 Å. This reaction serves the dual purpose of carbon sequestration and yielding hydrogen gas.

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“…1), as described in previous articles. 9,10 To avoid unexpected reactions on the reactor surface, we used a gold inner reactor (thickness 0.5 mm). Each trial used a charge of 0.4 g of activated carbon and a mixture totaling 75 mmol of three carbonates, sodium carbonate (Na 2 CO 3 ), potassium carbonate (K 2 CO 3 ), and lithium carbonate (Li 2 CO 3 ), in the inner reactor.…”

Section: Methodsmentioning

confidence: 99%

Influence of mixed molten carbonate composition on hydrogen formation by steam gasification

Kamo

Egami

et al. 2011

J Mater Cycles Waste Manag

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Steam gasifi cation in the presence of carbonate compounds is an effective method to recover useful materials from electronic waste streams by converting plastics into gaseous products that can be used for energy production and avoiding the expensive manual disassembly process. We investigated steam gasifi cation of activated carbon in the presence of various mixtures of lithium carbonate, sodium carbonate, and potassium carbonate. The activated carbon was almost completely converted into hydrogen and carbon dioxide at 700°C under 0.1 MPa pressure in the presence of carbonate mixtures. Carbon dioxide was also derived from partial decomposition of lithium carbonate. Steam gasifi cation was accelerated in the presence of various carbonate mixtures and at increasing steam partial pressures. These experimental results show that fl uidity of carbonates, the potassium content of the carbonate, and the steam partial pressure are important factors in accelerating steam gasifi cation.

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Effect of steam and sodium hydroxide for the production of hydrogen on gasification of dehydrochlorinated poly(vinyl chloride)

Cited by 20 publications

References 17 publications

Molten catalytic coal gasification with in situ carbon and sulphur capture

Molten catalytic coal gasification with in situ carbon and sulphur capture

Catalytic Studies of Sodium Hydroxide and Carbon Monoxide Reaction

Influence of mixed molten carbonate composition on hydrogen formation by steam gasification

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