Biomass gasification with pure steam in a fluidized bed is a highly endothermal process that has been connected in several ways to a fluidized-bed combustor to burn the char that is generated in the gasifier. This resulted in what currently is called dual fluidized-bed (DFB) biomass gasifiers. This review starts by describing the pioneering DFB biomass gasifiers that were operated during the period of 1975-1990 by Kunii's group in Japan, Battelle-Columbus and FERCO in the United States, TNEE in France, AVSA in Belgium, etc., ... and Corella and Herguido's gasifier, which was operated during the period of 1989-1991. A description of the gasifiers operated today in Europe (TU Wien and Gu ¨ssing in Austria and ECN in The Netherlands), Japan (IHI Co., EBARA, AIST-Tsukuba), and the People's Republic of China (Dalian, Hangzhou, and Beijing) then is given. Their most-relevant operation data, and the results from these gasifiers (mainly, the gaseous hydrogen (H 2 ) and tar contents in the raw produced gas), are finally presented briefly.
This paper addresses the H 2 production with simultaneous CO 2 capture by steam gasification of coal in a fluidized bed, at low/medium temperatures (600-800 °C) and atmospheric pressure. This work is mainly aimed at reviewing the effects of the inorganic species present in the matrix of the coal or added to the gasifier bed. The most promising species seems to be the calcined limestone (CaO), which intervenes in the overall gasification reaction network in at least five different types of reactions. The effectiveness of the CaO for CO 2 capture in the coal gasifier is, therefore, affected/influenced by the other four simultaneous or competitive types of reactions in the gasifier. The effects of the temperature in the gasifier and of the (CaO/ coal) ratio fed to the gasifier are finally reviewed and discussed in detail.
After several years of research with a single-layer-based monolithic reactor, a new, second-generation monolithic
reactor was designed, manufactured, set-up, and tested for tar and NH3 elimination from a real gasification
gas. This gas was produced in an upstream bubbling fluidized-bed biomass gasifier at small pilot-plant scale
(5−10 kg/h) and operated under conditions close to those used in large pilot and commercial units. The life
of the monolith, which is more important in this application than its activity, is dependent basically on the
longitudinal profiles of temperature in the entire monolithic reactor which must be optimal, avoiding very
high and very low temperatures at the front and at the exit, respectively, of the monoliths. The longitudinal
profile of temperature was modified and approached the optimal profile by dividing or partitioning the total
air flow to the entire gasification plant into four different flows: two (first and second flows) to the gasifier
(bottom and freeboard) and two (the third and fourth flows) to the monolithic reactor, to reheat the gasification
gas before it enters the two layers of monoliths. Through the use of an optimal distribution of the air, the
performance of the monolithic reactor was good and tar contents as low as 150 ± 50 mg/Nm3 were obtained
in the tests reported here.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.