Fluidized Bed Catalytic Reactor Research Articles

Modelling of fluidized bed reactors—II: Uniform catalyst temperature and concentration

A model based on the simple two phase theory of fluidization including the catalyst particles as a third phase has been developed for a nonisothermal fluidized bed catalytic reactor with continuous circulation of catalyst particles. The dilute phase is assumed to be in plug flow, the emulsion phase gas is considered to be perfectly mixed and the particles are assumed to be perfectly mixed and uniform. Exact criteria for uniqueness and multiplicity of the steady state solutions are presented and some conclusions derived therefrom. Several examples illustrating the influence of some parameters on the steady state multiplicity are reported. The steady states are analyzed for local asymptatic stability using Liapunov's direct method, but the sufficient conditions for stability are found to be rather conservative. Numerical examples illustrating the transient behavior of the system are presented, and it has been found that the initial temperature of the catalyst particles is a predominant factor in determining which steady state will be approached.

Analysis of a model for a nonisothermal continuous fluidized bed catalytic reactor

A three-phase model, consisting of a dilute or bubble phase, an interstitial gas phase and a solids phase, has been developed for a non-isothermal gas fluidized-bed catalytic reactor with continuous circulation of catalyst particles. The dilute phase is assumed to be in plug flow, the interstitial gas is considered to be either perfectly mixed or in plug flow, and the particles are assumed to be perfectly mixed. It is shown that the conversion in a reactor and steady state temperature and concentration profiles are the same irrespectively of the assumed flow pattern in the interstitial gas. The numerical computations were done for the case of a single irreversible reaction with or without catalyst decay and for the case of two consecutive irreversible reactions. In the case of an adiabatic reactor and ordinary exothermic reactions, or in the case of a cooled reactor with a highly exothermic reaction, multiple steady states may occur.

Countercurrent Backmixing Model for Fluidized Bed Catalytic Reactors. Applicability of Simplified Solutions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCountercurrent Backmixing Model for Fluidized Bed Catalytic Reactors. Applicability of Simplified SolutionsColin Fryer and Owen E. PotterCite this: Ind. Eng. Chem. Fundamen. 1972, 11, 3, 338–344Publication Date (Print):August 1, 1972Publication History Published online1 May 2002Published inissue 1 August 1972https://doi.org/10.1021/i160043a009RIGHTS & PERMISSIONSArticle Views278Altmetric-Citations52LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (629 KB) Get e-Alerts

Bubble assemblage model for fluidized bed catalytic reactors

A new model for catalytic reaction in fluidized beds is developed. This model called the “Bubble Assemblage Model” is based on multiple bubbles of varying sizes with interchange of gas taking place between the bubble phase and the emulsion phase. Since the model needs no adjustable parameters, it is believed that the model is useful for study in scale-ups. The model proposed is also convenient for computer simulations. Experimental data from various investigators were used to test the validity of this model. It was found that the conversions predicted using this model agree reasonably well with the actual performance of the fluidized beds.

流動層触媒反応装置の数学的モデル

流動層触媒反応装置を設計する場合,反応操作条件から反応成積を予知する必要がある。本研究は,この種の設計計算に活用できるような数学的モデルを導出するのが目的である。本研究では,従来発表された2相モデルと逆混合の槽列モデルの概念をそれぞれ修正して組み合わせ,新らしい数学的モデルとしてここに分割モデルを提出した。分割モデルでは,流動層内の気泡の直径と同等な高さに,流動層を軸方向に適当な段数に分割し,さらに,各段内にガスポケットの気泡相(B相)と固体粒子群のエマルジョン相(E相)とからなる多くのセルを想定した。各セル内のガスの流れは,B相およびE相ともに完全混合状態であるとし,E相内でのガス流速と空間率は流動化開始時の状態に保たれているとみなし,各セルの高さ,各セル内で逆混合するガス量などを適当な仮定のもとで求めた。分割モデルと統一2相モデルとを比較して,両者のパラメーターの関係を明らかにして,充填層と流動層の逆混合機構を関連ずけ,さらに未知のパラメーターを含む両相間ガス交換速度係数は, Mathisらの2相モデルでのガス交換速度の実験値とHarrisonらの関係式を利用して算定し,このようにしてえたガス交換速度係数は逆混合の程度に比例することが解った。本研究では,分割モデルを使って,不均一型流動層反応装置の反応成績を操作条件から求める計算方法を示し,ここに提出した数学的モデルの実用性を確かめた。