Reversibility of Combustion Processes

Richter, H.J.; Knoche, K. F.

doi:10.1021/bk-1983-0235.ch003

Cited by 404 publications

(249 citation statements)

References 0 publications

Supporting

Mentioning

249

Contrasting

Order By: Relevance

“…Since the birth of chemical looping combustion (Richter andKnoche, 1983, Ishida et al, 1987), this technology has been the object of intense research worldwide due to its potential in clean combustion and combined heat and power (Son and Kim, 2006). Absorption enhanced gasification/reforming is used for syngas and H 2 production from coal (Lin et al, 2001) and biomass (Marquardt-Mollenstedt et al, 2004).…”

Section: Second Half Of Cycle: Fuel-steam Feedmentioning

confidence: 99%

Production of hydrogen by unmixed steam reforming of methane

Dupont

Ross

Knight

et al. 2008

Chemical Engineering Science

View full text Add to dashboard Cite

Unmixed steam reforming is an alternative method of catalytic steam reforming that uses separate air and fuel-steam feeds, producing a reformate high in H 2 content using a single reactor and a variety of fuels. It claims insensitivity to carbon formation and can operate autothermally. The high H 2 content is achieved by in-situ N 2 separation from the air using an oxygen transfer material (OTM), and by CO 2 capture using a solid sorbent. The OTM and CO 2 sorbent are regenerated during the fuel-steam feed and the air feed respectively within the same reactor. This paper describes the steps taken to choose a suitable CO 2 -sorbent material for this process when using methane fuel with the help of micro reactor tests, and the study of the carbonation efficiency and regeneration ability of the materials tested. Elemental balances from bench scale experiments using the best OTM in the absence of the CO 2 sorbent allow identifying the sequence of the chemical reaction mechanism. The effect of reactor temperature between 600 and 800°C on the process outputs is investigated. Temperatures of 600°C and 800°C under the fuel-steam feed were each found to offer a different set of desirable outputs. Two stages during the fuel-steam feed were characterised by a different set of global reactions, an initial stage where the OTM is reduced directly by methane, and indirectly by hydrogen produced by methane thermal decomposition, in the second stage, steam reforming takes over once sufficient OTM has been reduced. The implications of these stages on the process desirable outputs such as efficiency of reactants conversion, reformate gas quality, and transient effects are discussed.

show abstract

Section: Second Half Of Cycle: Fuel-steam Feedmentioning

confidence: 99%

Production of hydrogen by unmixed steam reforming of methane

Dupont

Ross

Knight

et al. 2008

Chemical Engineering Science

View full text Add to dashboard Cite

show abstract

“…CLC concept based on the rationale of generating pure CO 2 was first proposed by Lewis and Gilliland [5]. This concept was recovered by Richter and Knoche in the 1980's as a highly efficient process for energy generation [6]. In CLC technology, combustion is split into separate reduction and oxidation: oxygen needed for the combustion of fuel is provided by one solid oxygen carrier, such as a metal oxide; and air is used to regenerate the oxygen carrier.…”

Section: Introductionmentioning

confidence: 99%

“…Later, combustion tests for several solid fuels, including anthracite, lignite and pine wood, were done [24][25][26]. Totally, 40 h for continuous combustion 6 under various conditions was accomplished. Complete combustion of the solid fuel was reached in all the cases and CO 2 capture rates higher than 95% were usually obtained.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a sol–gel derived CuO/CuAl2O4 oxygen carrier for chemical looping combustion (CLC) of gaseous fuels: Relevance of gas–solid and oxygen uncoupling reactions

Mei

Abad

Zhao

et al. 2015

Fuel Processing Technology

View full text Add to dashboard Cite

A new sol-gel CuO/CuAl 2 O 4 material was characterized for chemical looping combustion (CLC) with gaseous fuels, including the analysis of the relevance of the oxygen uncoupling mechanism in oxygen transference was considered. This material possesses high reactivity and oxygen transport capacity, which combines the best features of the previously reported impregnated and spray-dried materials. A new test based on thermogravimetric analyzer (TGA) was designed and performed, from which the composition of this new material was determined. During the cycle tests in alternating N 2 and air, it was found that CuO decomposed fully into Cu 2 O in N 2 and later completely regenerated to CuO in air, similarly to chemical looping with oxygen uncoupling (CLOU) for solid fuels. However, the decomposition of CuAl 2 O 4 to CuAlO 2 was quite slow, and the followed regeneration of this compound cannot be accomplished. Subsequently, high numbers of cycles (>50 cycles) with gaseous fuels were conducted, which suggested adequate and stable rate for the combustion of the gaseous fuels with this oxygen carrier. The material undergone such cycles with gaseous fuels was then subjected to oxygen release and uptake cycles. It was observed that the CuO/CuAl 2 O 4 was reconstructed after using in gaseous fuels combustion. This behavior resulted in the segregation of CuO from Al 2 O 3 in the CuAl 2 O 4 , producing higher amount of free CuO and thus more available oxygen for CLOU with respect to the initial material. This is a new observation for this kind of material. Finally, the relative importance of gas-solid reactions in CLC against oxygen uncoupling in CLOU was examined when a fuel gas was presented in the reacting atmosphere, which, as one of the novelties of this paper, was never reported before.

show abstract

“…More specifically, this study is focused on the so-called Chemical Looping technology. This technology was first applied to combustion processes with CO 2 capture [13][14][15][16]. Chemical…”

Section: Introductionmentioning

confidence: 99%