Dupont's CFB technology for maleic anhydride

Contractor, R.M.

doi:10.1016/s0009-2509(99)00295-x

Cited by 111 publications

(72 citation statements)

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“…This mechanism can also be developed into a two step process where the oxidation of substrate and the re-oxidation of reduced catalyst are performed in separate steps which can deliver selectivity and heat transfer advantages when the target product is, e.g., susceptible to further oxidation in the gasphase. The selective oxidation of butane to yield maleic anhydride provides an example of a catalytic process for which such a two-stage procedure has been investigated [6]. In addition to oxidation reactions catalysed by metal oxides, Mars-van Krevelen-like reaction mechanisms are documented for other types of reaction [7], for example those involving sulfide [8] and carbide [9,10] catalysts.…”

Section: Introductionmentioning

confidence: 99%

The Denitridation of Nitrides of Iron, Cobalt and Rhenium Under Hydrogen

2013

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The denitridation behaviour of binary iron, cobalt and rehnium nitrides under H 2 /Ar has been investigated. The iron nitride was found to lose over 70 % of its as prepared nitrogen content at 400°C. The cobalt nitride was completely denitrided at 250°C. Rhenium nitride lost close to 90 % of its nitrogen at 350°C. In addition, Co-Re 4 prepared by ammonolyis was investigated, whilst only traces of NH 3 were lost from this material under H 2 /Ar at 400°C, with H 2 /N 2 it proved to be an active ambient pressure ammonia synthesis catalyst in accordance with previous literature.

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Section: Introductionmentioning

confidence: 99%

The Denitridation of Nitrides of Iron, Cobalt and Rhenium Under Hydrogen

2013

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“…However, in recent years, research has focused more on atmospheric pressure systems because of the operational challenges of solids circulation at high pressure, as CO 2 separation has a minimal energy penalty even at atmospheric pressure. In addition to using the chemical looping scheme for combustion, the scheme has been proposed as a method to produce syngas [5], hydrogen [6], maleic anhydride [7], methanol [8], and sulfuric acid [9].…”

Section: Introductionmentioning

confidence: 99%

Chemical Looping Combustion of Hematite Ore with Methane and Steam in a Fluidized Bed Reactor

2017

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Chemical looping combustion is considered an indirect method of oxidizing a carbonaceous fuel, utilizing a metal oxide oxygen carrier to provide oxygen to the fuel. The advantage is the significantly reduced energy penalty for separating out the CO 2 for reuse or sequestration in a carbon-constrained world. One of the major issues with chemical looping combustion is the cost of the oxygen carrier. Hematite ore is a proposed oxygen carrier due to its high strength and resistance to mechanical attrition, but its reactivity is rather poor compared to tailored oxygen carriers. This problem is further exacerbated by methane cracking, the subsequent deposition of carbon and the inability to transfer oxygen at a sufficient rate from the core of the particle to the surface for fuel conversion to CO 2 . Oxygen needs to be readily available at the surface to prevent methane cracking. The purpose of this work was to demonstrate the use of steam to overcome this issue and improve the conversion of the natural gas to CO 2 , as well as to provide data for computational fluid dynamics (CFD) validation. The steam will gasify the deposited carbon to promote the methane conversion. This work studies the performance of hematite ore with methane and steam mixtures in a 5 cm fluidized bed up to approximately 140 kPa. Results show an increased conversion of methane in the presence of steam (from 20-45% without steam to 60-95%) up to a certain point, where performance decreases. Adding steam allows the methane conversion to carbon dioxide to be similar to the overall methane conversion; it also helped to prevent carbon accumulation from occurring on the particle. In general, the addition of steam to the feed gas increased the methane conversion. Furthermore, the addition of steam caused the steam methane reforming reaction to form more hydrogen and carbon monoxide at higher steam and methane concentrations, which was not completely converted at higher concentrations and at these residence times.

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“…In 1996, DuPont commercialized the n-butane oxidation process based on circulating fluidized bed (CFB) technology, 3 in which oxidation and reduction processes were carried out in separate vessels. Independent optimization of oxidation and reduction allowed significant increase in the selectivity of maleic anhydride.…”

Section: Introductionmentioning

confidence: 99%

Modeling of partial oxidation in gas–solids downer reactors

2009

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Selective partial oxidations represent an important class of reactions in the process industry. Of particular interest is the partial oxidation of n-butane to maleic anhydride (MAN), which is arguably the largest commercialized alkane partial oxidation process. Partial oxidation of n-butane, which uses vanadium phosphorous oxide (VPO) as a heterogeneous catalyst, is believed to operate through a unique mechanism in which lattice oxygen oxidizes n-butane selectively to MAN. Past work has shown that performing partial oxidation reactions in gas-solids riser configuration is realizable and commercially viable, which has lead to commercialization of this technology in the last decade. Though the riser configuration allows optimal and independent control of the oxidation and reduction steps, the riser unit suffers from solid backmixing at walls, which in turn result into lower conversion, nonoptimal selectivity and diminished overall yield of desired product. In recent years, there has been growing interest in downers involving cocurrent downflow of both solids and gas phases, hence offering relatively uniform flow characteristics. In this contribution, we explore through modeling the implications of effecting partial oxidation reactions in a downer (gas-solids cocurrent downflow) compared to that in a conventional riser reactor (gas-solids cocurrent up flow) operated under equivalent operating conditions. Further, we explore the operational space of downers for these reactions, suggesting ways for improving the productivity of downer for partial oxidation applications. V

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Dupont's CFB technology for maleic anhydride

Cited by 111 publications

References 0 publications

The Denitridation of Nitrides of Iron, Cobalt and Rhenium Under Hydrogen

The Denitridation of Nitrides of Iron, Cobalt and Rhenium Under Hydrogen

Chemical Looping Combustion of Hematite Ore with Methane and Steam in a Fluidized Bed Reactor

Modeling of partial oxidation in gas–solids downer reactors

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