Hydrogen production from 2-propanol as a key reaction for a chemical heat pump with reaction couple of 2-propanol dehydrogenation/acetone hydrogenation

Saito, Yasukazu; Yamashita, Masaru; Ito, Eri; Meng, Ning

doi:10.1016/0360-3199(94)90089-2

Cited by 30 publications

(5 citation statements)

References 18 publications

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“…The vaporization of Br 2 increases the Seebeck coefficient; however, the extremely corrosive Br 2 vapor limits its application. Previously, a thermally regenerative fuel cell, using hydrogenation of acetone to iso-propanol, was studied by Ando and co-workers. − A chemical heat pump involving dehydrogenation of iso-propanol and hydrogenation of acetone was studied by Saito and co-workers. − However, no study on the Seebeck coefficient and thermoelectric power of a thermocell based on this couple has been reported.…”

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confidence: 99%

High Seebeck Coefficient Electrochemical Thermocells for Efficient Waste Heat Recovery

Zhou

Liu

2018

ACS Appl. Energy Mater.

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An electrochemical thermocell realizes thermal to electric energy conversion when two electrodes operate the same reversible reaction but at different temperatures. Its Seebeck coefficient is determined by the entropy change of the redox reaction. Here we report a thermocell containing acetone and iso-propanol as the redox couple, which can achieve the highest reported Seebeck coefficient of −9.9 mV K −1 when the hot side is above the boiling point of acetone. Vaporization entropy of acetone increases the total entropy change in the conversion of iso-propanol to acetone. In addition, a concentration gradient of acetone caused by evaporation and condensation increases the cell voltage significantly. Stable performance of the thermocell is enabled by a Pt−Sn catalyst operating in a neutral pH electrolyte solution. The possibility of utilizing a liquid−gas phase change to increase the Seebeck coefficient of thermocells opens a new venue for exploration.

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mentioning

confidence: 99%

High Seebeck Coefficient Electrochemical Thermocells for Efficient Waste Heat Recovery

Zhou

Liu

2018

ACS Appl. Energy Mater.

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“…The composite Ru-Pt catalyst and its surface modification with Pt(acac) 2 or Pd(acac) 2 exhibited an activity enhancement [41]. With Ru-Pd/C as a catalyst, Gaspillo et al [23] measured the reaction rate of gas-phase isopropanol in a fixed-bed reactor and found that the conversion was limited to 10.8 % at 363 K due to the equilibrium.…”

Section: Organic Catalytic Reactionmentioning

confidence: 98%

Advances in Organic Liquid‐Gas Chemical Heat Pumps

Huai

et al. 2011

Chem Eng & Technol

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Compared with inorganic chemical heat pumps (CHPs), organic liquid-gas CHPs are more amenable to be run as a continuous process because the reactants and products can be fed or removed continuously. Therefore, increasing attention has been paid to investigations of CHPs using the organic liquid-gas reaction system. Relevant research topics involved reaction catalyst, chemical reaction kinetics, reactive distillation, energy efficiency evaluation, economic analysis, etc. Nevertheless, the research on an organic liquid-gas CHP system is still in the elementary stage. A detailed review on the current research status of catalyst-assisted CHPs employing an organic liquid-gas reaction system has been performed. Existing problems are identified and future research directions are proposed.

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“…In R 1 , a pure P gas flow of N 1 mol s −1 is dehydrogenated at temperature T m , yielding an equilibrium mixture at T m of A, H and P. A total amount of heat Q m is needed for the dehydrogenation reaction and separation. In R 2 , an equivalent molar gas mixture of A and H with a variable amount of P yields an equilibrium mixture at a high temperature T h of A, H and P. Different from previous publications on this type of heat transformer, for example [1][2][3][4][5], we consider here the possibility of P being present in the gas flow entering R 2 as a result of incomplete separation in SEP. The amount of P in the gas flow entering R 2 must be low enough in order to yield an exothermic hydrogenation reaction of A with H instead of the endothermic dehydrogenation of P. The hydrogenation reaction in R 2 yields an amount of heat Q h at the high temperature level T h .…”

Section: Analysesmentioning

confidence: 99%

“…Different from previous publications, we consider here the possibility that the dehydrogenation temperature T m in R 1 is higher than temperature T b of the heat engine SEP. Usually, see for example [1][2][3][4][5], the SEP is a distillation column with T b as the boiling point of P in the reboiler, i.e. 356 K [10], and with T l as the boiling point of pure A in the condenser, i.e.…”

Section: Analysesmentioning

confidence: 99%

“…A chemical heat transformer uses an equilibrium reaction for the internal cycle of the heat transformer. An example of an equilibrium reaction for chemical heat pump applications is the endothermic dehydrogenation of 2-propanol (P), yielding acetone (A) and hydrogen (H), versus the exothermic hydrogenation of A yielding P, see for example [1][2][3][4][5]. In [1][2][3][4][5], it is suggested that such chemical heat transformers may have a high thermal efficiency, η th , as defined by…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Entropy production in the chemical reaction driven heat transformer

Wojcik¹,

Kooi²,

Maschmeyer³

2001

J. Phys. D: Appl. Phys.

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A chemical heat transformer uses a chemically reacting system for the internal cycle. Chemical conversions in a chemical heat transformer produce entropy due to irreversibilities, which are taken into account in our derivation of a new, more realistic value for the thermal efficiency of this heat transformer. We studied the example of the endothermic dehydrogenation of 2-propanol, yielding acetone and hydrogen, versus the exothermic hydrogenation of acetone yielding 2-propanol. Different from other papers we allow the dehydrogenation temperature Tm to be higher than the boiling point Tb of the 2-propanol and we allow the isolation of 2-propanol from the mixture to be incomplete. The internal entropy production in the dehydrogenation and hydrogenation reactor is calculated as a function of the hydrogenation temperature Th with three different values of Th-Tm and several incomplete separation values. The thermal efficiency is much lower than Carnot's efficiency for low-temperature lifts because of the high irreversibilities that are already present for these temperatures and because of the low efficiency of the heat engine. A higher, but still low, efficiency is obtained for Tm>Tb and for the incomplete separation of 2-propanol from the mixture.

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Hydrogen production from 2-propanol as a key reaction for a chemical heat pump with reaction couple of 2-propanol dehydrogenation/acetone hydrogenation

Cited by 30 publications

References 18 publications

High Seebeck Coefficient Electrochemical Thermocells for Efficient Waste Heat Recovery

High Seebeck Coefficient Electrochemical Thermocells for Efficient Waste Heat Recovery

Advances in Organic Liquid‐Gas Chemical Heat Pumps

Entropy production in the chemical reaction driven heat transformer

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