Fluidized Catalyst Bed Research Articles

NOx reduction by the Econ‐Nox™ SCR process

AbstractSCR systems are used extensively in Japan and West Germany to eliminate 80–90% NOx emissions from utility boilers and industrial furnance stacks. Costs have been lowered considerably over the past ten years. Further reduced costs and stringent regulations on NOx emission make this simple system attractive for refinery and industrial process heaters, boilers, and gas turbines.The Econ‐NoxTM process uses a fluidized catalyst bed to accomplish selective total reduction of oxides of nitrogen to elemental nitrogen using ammonia as a reactant. The process can be designed for operating temperatures between 550°F and 750°F and for a wide range of operating variables.The process brings together some old technology on selective reduction chemistry, relatively new fluidized bed oxidation techniques and a non‐precious metal Econ‐AcatTM catalyst which permits operation over a broader temperature range than has been practical in the past.This paper reports some of the distinctions made between this reactor configuration and the historical thermal and catalytic systems used for this type of process.

Development of a fluidized bed catalyst for the oxidation of n-butane to maleic anhydride

A series of fluidized bed catalysts for the preparation of maleic anhydride (MA) from n-butane was prepared by encapsulation, embedding, or impregnation of the active and selective catalytic material. The catalysts were characterized by their fluidization and their catalytic properties. The optimization of the performance of fixed bed catalysts by statistical experimental design followed. Finally, the above-mentioned different methods of adjusting the material to a fluidized bed process were studied

Catalytic Fuel Combustion—A Way of Reducing Emission of Nitrogen Oxides

The present survey has shown that catalytic combustion can be successfully applied to various domestic and industrial fuel-burning devices for improving combustion efficiency and thermal NO x control. The investigation of kinetics of oxidation of nitrogen-containing compounds on solid catalysts has shown that the fuel NO x yield can be decreased by the use of oxide catalysts rather than platinum ones, by low excess air operation, and by decreasing the combustion of fuels in a fluidized catalyst bed in catalytic heat generators makes it possible to conduct technological processes at high fuel loads on a catalyst and at rather low temperatures in the combustion zone (770-1070 K) owing to the combination of heat evolution and heat removal in the same catalyst bed

Fluidized-bed catalyst cracking regenerator modelling and analysis

Three different models for describing a fluidized-bed catalyst cracking regenerator are studied, namely the grid-effect, two-region and bubbling-bed models. Comparisons of the computed results with actual operating data are also made so that a suitable model for simulation and prediction of the effects of the operating variables on the process may be carefully selected. A working regenerator from the Kaohsiung Oil Refinery is used for a case study. We conclude that the bubbling-bed model of the fluidized-bed catalyst reactor, with the proposed two thermally uniform stages to account for the heat balance, is able to describe this regenerator with the smallest error. The influence of operating variables such as the catalyst circulation rate, catalyst input temperature, initial coke content and air flow rate on the coke conversion and catalyst temperature are also studied.

Influence of chemical non-steady-state on SO2 conversion in fluidized catalyst bed

The effect of the influence of catalyst non-steady-state on SO2 conversion ion a fluidized catalyst bed has been studied depending on the ratio of relaxation time for the catalytic reaction step to the characteristic time of particles diffusion.

Effect of internal baffles on conversion of hydrogen chloride oxidation and pressure fluctuations in a fluidized catalyst bed.

Effect of internal baffles on conversion of hydrogen chloride oxidation and pressure fluctuations in a fluidized catalyst bed.

Thermal conversion of lignite in a fluidized bed of catalyst

The results are presented of a physico-chemical investigation of thermal conversion of lignite in a fluidized bed of oxidation catalyst. Use of the catalyst allows an autothermal process at temperatures associated with low temperature pyrolysis processes. Quantitative aspects of the autothermal lignite pyrolysis process, and the compositions of the solid and gaseous products, have been studied. A model of lignite particle decomposition under conditions of flash pyrolysis is proposed.

Coke formation in cracking gasoil from atmospheric resid with activating additive

The authors report on an investigation of catalytic cracking of a vacuum gasoil obtained from atmospheric resid, with an activating additive. Three samples of vacuum gasoil were used in this work: Sample 1 was taken from a commercial unit, the atmospheric resid being distilled without additive; Sample 2 was taken from the same unit, with laboratory distillation of the atmospheric resid with 1.5% extract by weight; Sample 3 was prepared from Sample 2 by adding the extract as an activating additive before catalytic cracking. The physicochemical characterizing of Samples 1 and 2 are listed. Because of the low concentration of additive, the composition and properties of Sample 3 were practically the same as Sample 2. All three feeds were cracked in a flow-type laboratory unit with a stationary fluidized bed of zeolite-containing catalyst.

Catalytic cracking of vacuum distillate with additives in fluidized catalyst bed

The authors report on a study of the catalytic cracking of straight-run 350-500/sup 0/C vacuum distillates differing substantially in contents of aromatic hydrocarbons and resins, as influenced by the addition of an extract from the No. III lube cut from West Siberian crude. The experiments were performed in a standard catalytic cracking unit in the fluidization mode, using KMTsR zeolitic microbead catalyst.

Variation of hydrocarbon group composition of products from catalytic cracking of a vacuum distillate feed

The relationships in the conversion of various groups of hydrocarbons of a vacuum distillate from a medium-sulfur crude of the Romashkino type by cracking on a powdered zeolitic catalyst was investigated in a continuous pilot unit in reactors of three types: with a fluidized bed of catalyst, cocurrent-flow with a final fluidized bed of catalyst, and cocurrent-flow. A simultaneous investigation was made of the relationships in the accumulation of various groups of hydrocarbons in the craced products.

Mass transfer coefficients and amounts of direct‐contact‐catalyst in fluidized catalyst beds

The Canadian Journal of Chemical EngineeringVolume 62, Issue 5 p. 610-616 Article Mass transfer coefficients and amounts of direct-contact-catalyst in fluidized catalyst beds Shintaro Furusaki, Shintaro Furusaki Department of Chemical Engineering, University of Tokyo, Tokyo 113, JapanSearch for more papers by this authorYasuhiko Nozaki, Corresponding Author Yasuhiko Nozaki Department of Chemical Engineering, University of Tokyo, Tokyo 113, JapanFuji Standard Research Co., Tokyo and K. Nakagiri is with Shin-Nippon Steel & Chemical Co., Kita-Kyushu, JapanSearch for more papers by this authorKuniharu Nakagiri, Kuniharu Nakagiri Department of Chemical Engineering, University of Tokyo, Tokyo 113, JapanSearch for more papers by this author Shintaro Furusaki, Shintaro Furusaki Department of Chemical Engineering, University of Tokyo, Tokyo 113, JapanSearch for more papers by this authorYasuhiko Nozaki, Corresponding Author Yasuhiko Nozaki Department of Chemical Engineering, University of Tokyo, Tokyo 113, JapanFuji Standard Research Co., Tokyo and K. Nakagiri is with Shin-Nippon Steel & Chemical Co., Kita-Kyushu, JapanSearch for more papers by this authorKuniharu Nakagiri, Kuniharu Nakagiri Department of Chemical Engineering, University of Tokyo, Tokyo 113, JapanSearch for more papers by this author First published: October 1984 https://doi.org/10.1002/cjce.5450620506Citations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume62, Issue5October 1984Pages 610-616 RelatedInformation

Parallel consecutive reactions in a fluidized catalyst bed

The two-phase model of Werther is applied to a parallel consecutive triangular reaction scheme. An analytical solution is obtained and used to predict the performance of a fluidized bed reactor producing maleic anhydride from benzene oxidation. The model predictions agree with experimental data. The model is also useful for examining the sensitivity of various parameters, thus guiding the direction of future experiments.

Effect of volume change on conversions in fluidized catalyst beds

Description d'un modele mathematique base sur le modele des deux phases, pour predire le taux de conversion d'une reaction comportant un nombre decroissant de moles en lit fluidise. Application a l'analyse de la methanation de CO

Methanation of carbon monoxide by a fluidized catalyst bed.

Methanation of CO in a fluid bed, carried out by Ni catalyst at 573K and atmospheric pressure, was studied experimentally and theoretically. Reaction rates of methanation and the water-gas shift reaction were measured in a fixed bed reactor. A fluid bed model considering a decrease in number of moles caused by reactions is proposed to analyze the data obtained with a fluid bed reactor of 8.1cm i.d. An effective bubble diameter is introduced as an adjustable parameter in the model. The experimental results are well explained by the model when the bubble diameter is assumed to be 3.6cm. It is found that the influence of the decrease in number of moles on conversion cannot be ignored in analyzing the fluid-bed reaction data.

Effect of Particle Density on Fluidity of Fluidized Catalyst Bed and Evaluation of Fluidity

FCC粒子および, それとほぼ同等な平均粒径, 粒径分布, 44μm以下の微小粒子の含有割合をもつが粒子密度の大きい2種類の粒子を, 内径5.2～50cmの塔で60cm/s以上まで到るガス空塔速度で流動化し, これらの粒子の流動状態を調べた.FCC粒子は円滑な流動性を示すが, 密度の大きい粒子は層高が深い場合極度のチャンネリングを生じる.ガス空塔速度を高くすることによりこのチャンネリングを弱めることは可能であり, その遷移速度は, 粒径分布が等しい場合, 粒子密度により異なる.平均粒径を小さくとり, 粒径分布を広くすることのみでは, 必ずしも流動触媒層の流動を良好にすることができるとは限らず, 粒子密度が流動性に重要な影響を及ぼす.気泡塔の循環流理論に基づいた, ガスのホールドアップに関するプロットを行うことにより, 粒子の流動性の判定が可能である.

Determination of Bed Parameters by Utilizing Gas Absorption for a Fluidized Catalyst Bed of Fine Particles

流動化した粒子に担持されたアルカリ水溶液への空気中の炭酸ガスの吸収を用いて室温下で塔径0.10m, 高さ2mの流動触媒層で測定された吸収データを調べた.空気の空塔速度UGが0.1～0.6m/sでの実験結果をLewis-Gilliland-Glassプロットを用いて逐次接触モデルにより解析した。次に, 熱線プローブを用いて気泡測定を行い, 吸収速度データと共に検討した結果, (1) 気泡-エマルジョン相間の物質移動の総括容量係数は0.29～0.74s-1でありその差異は気泡ホールドアップの差異による, (2) ガスと直接に接触する粒子のBed全粒子に対する割合は0.18×UG1.2で表わせ, この値は稀薄相中に存在する粒子のBed全粒子に対する割合と比較的良く一致した. (3) 熱線法による気泡測定によって得られた塔中心軸上の平均気泡径はアルカリを担持したアルミナ粒子, 未担持のFCC粒子, アルミナ粒子に対して各々 (3.2, 2.2, 1.4) ×10-2mであり, それぞれの場合の気泡上昇速度は用いた粒子にかかわらずほぼ一定値を示し, その大きさは約0.9m/sであった.

Procedure for testing CO oxidation promoters in laboratory units

This article proposes a procedure for studying the dependence of the relative conversion of CO to CO/sub 2/ on the content of the promoter KO-4 or KO-9 in a sample of catalyst that had been precoked to a carbon content of 3.5% by weight. It is determined that as the content of the promoter dropped from 1% to 0.1% by weight, the relative conversion of CO to CO/sub 2/ changed very little. The goals of the experiments in a reactor with a vibrofluidized catalyst bed were to determine the approximate content of the promoter in the fluidized catalyst bed that is required for complete conversion of CO to CO/sub 2/, and to develop a rapid procedure for the comparative evaluation of the oxidation activity of promoters. The tests were performed under conditions such that the operating indexes of commercial unit regenerators would be approximated and complete oxidation of CO would be avoided. The high level of catalytic activity of the materials tested is demonstrated.

Certain relationships in deposition of coke on zeolitic cracking catalyst

This article investigates coke deposition in a single-pass flow unit with a stationary fluidized bed of catalyst with a cracking period of 1.25-20 min., feedstock mass velocity 1-6 h/sup -1/, and various cracking temperatures. Vacuum gasoils from different crudes were used as the feedstocks. Voorhie's equations are used for a quantitative description of coke deposition. The coke deposition on the catalyst is presented as a power function of the catalyst operating time and is independent of the feedstock mass velocity, and coke yield on feed is a power function of the conversion of feed and is likewise independent of the feedstock mass velocity. It is determined that the coke yield in the course of cracking on zeolitic catalyst varies exponentially with the feedstock conversion, regardless of the particular set of process conditions used to reach this conversion. The dependence of coke deposition on the catalyst of the feedstock conversion is also exponential, but each value of the catalyst: feedstock ratio (C:F) gives a different curve. Larger values of C:F correspond to less deposition of coke on the catalyst, and larger values of the latter correspond to more highly aromatic feedstocks.

Residual oil cracking with generation of hydrogen (Part 4). Proposal for a new cracking process with desulfurization of iron sulfide by roasting.

A sulfur-containing residual oil has been cracked in a fluidized bed of an iron-containing catalyst with hydrogen generation of 180Nl-H2/kg-feed oil by reaction of ferrous oxide with steam and of 30Nl-H2/kg-feed oil by dehydrogenation of the feed oil. The iron sulfide formed in the catalyst during partial oxidation of coke has been desulfurized by roasting with air in a fluidized bed roaster. The desulfurization reaction has been found to be fast enough to attain equilibrium during roasting. Based on these results, a new cracking process has been proposed. It consists of cracking sulfur-containing residual oil, generation of hydrogen, partial oxidation of coke on the catalyst, fixation of gaseous sulfur compounds in the catalyst, and roasting of the iron sulfide.

A New Method to Determine Bed Parameters of Fluidized Catalyst Beds by Use of Gas Absorption with Liquid Supported on Fine Particles

A New Method to Determine Bed Parameters of Fluidized Catalyst Beds by Use of Gas Absorption with Liquid Supported on Fine Particles