Intraparticle Mass Transfer Limitations Research Articles

Efficient methanol dehydration to DME and light hydrocarbons by submicrometric ZrO2-ZSM-5 fibrillar catalysts with a shell-like structure

Zeolites are widely used in many applications, such as catalysis and adsorption processes. The use of these materials in a nanometric size would be of great interest for these applications, due to the better performance they could exhibit in terms of avoiding intraparticle mass and heat transfer limitations. However, this small particle size results in high pressure drops in adsorption columns and fixed-bed reactors, making these materials non-applicable directly in the nanometric size. In this work, ZrO2 fibers with a mean diameter of 275 nm and the presence of small well-defined ZSM-5 zeolite aggregates of 550 nm in size around the ZrO2 submicrometric fibers, in the form of a shell-like structure, have been prepared by electrospinning technique, which resulted very active for the synthesis of DME and light olefins via methanol dehydration. The submicrometric fibrillar catalysts, without any further modification, could be easily structured inside a fixed-bed reactor, which worked very efficiently in terms of heat and mass transfer, avoiding, at the same time, the usual pressure drops problems of fixed-bed reactors working with catalyst particles of submicrometric size. Methanol conversion and selectivity to DME and light hydrocarbons could be finely controlled, for a given set reaction conditions, by tuning the zeolite loading in the structured catalyst. Apparent kinetic parameters for the selective methanol dehydration to DME were calculated assuming a reversible second order rate expression and an activation energy of 75 kJ/mol was obtained.

Carbon dioxide capture over amine functionalized styrene divinylbenzene copolymer: An experimental batch and continuous studies

Cement industries are the second-largest anthropogenic carbon dioxide (CO2) emitter and have gained substantial research attention to capture CO2 and minimize environmental issues. Also, the recovered carbon dioxide (CO2) can be reutilized for several applications. The adsorptive capture of CO2 appears promising as compared to absorption, membrane separations, and cryogenic distillation because it allows easy CO2 recovery. This work demonstrates the adsorptive capture of carbon dioxide on amine-functionalized styrene-divinylbenzene copolymer. Both batch and continuous adsorption data of CO2 are presented at different temperatures. The equilibrium uptake of CO2 over the polymeric adsorbent showed 2.4 mol/kg capacity at 25⁰C and near ambient pressure, which decreased by 16% with a ten-degree rise in the operating temperature. The equilibrium adsorption data are modeled with Langmuir, Nitta, Toth, Dubinin-Radushkevich, and SIPS isotherm equations to characterize the CO2-polymer adsorption system and estimate the heat of adsorption, entropy, and Gibbs free energy for CO2 adsorption. The Toth isotherm gave the best fit of the experimental data suggesting monolayer adsorption of CO2 on energetically different sites of the adsorbent. The diffusivity of CO2 within the adsorbent’s interstitial space is determined as 2–9 × 10−11 m2/sec, indicating intraparticle mass transfer limitations for large-scale operations. The continuous adsorption/desorption studies of CO2 in mixtures with nitrogen were characterized via breakthrough curves. The desorption studies showed 92–94% recovery of CO2 in batch and continuous experiments at 56⁰C. A theoretical model for continuous adsorption of CO2 is also developed and validated with the experimental data. The current work could be promising for CO2 capture in the cement industry.

Enhanced activity of a bifunctional Pt/zeolite Y catalyst with an intracrystalline hierarchical pore system in the aqueous-phase hydrogenation of levulinic acid

Mesopores in the range of 4 to 5 nm were introduced into zeolite Y (nSi/nAl = 16) by surfactant-templating. This method using a mixture of octadecyltrimethylammonium hydroxide and bromide (C18TAOH/C18TABr) yields a mesoporous zeolite (Y–C18TAOH) with a higher specific mesopore volume and only a small loss in crystallinity and specific micropore volume. After loading with Pt, the two bifunctional catalysts (2.7Pt/Y and 2.6Pt/Y–C18TAOH) were applied in the aqueous-phase hydrogenation of levulinic acid (LA) to γ–valerolactone (GVL) (pH2 = 2.5 MPa, 393 K). Intraparticle mass–transfer limitations present for the catalyst 2.7Pt/Y were not observed in the LA hydrogenation over the catalyst with the hierarchical pore system 2.6Pt/Y–C18TAOH. Changes in the acid and de-/hydrogenation functionality are shown not to be responsible for the high catalytic activity of 2.6Pt/Y–C18TAOH. The presence of additional mesopores in a bifunctional catalyst based on zeolite Y is proven to enhance the mass-transfer properties and the resulting catalytic activity in the aqueous-phase hydrogenation of LA for the first time.

Mass transfer limitations in binderless ZSM‐5 zeolite granules during adsorption of flavour compounds from aqueous streams

AbstractBACKGROUNDRecently, a new process concept has been proposed to selectively adsorb wort off‐flavours, i.e. aldehydes, from alcohol‐free beers with hydrophobic zeolites.RESULTSIn this work, we investigated the uptake of a mixture of wort flavour compounds (2‐methylpropanal, 2‐methylbutanal, 3‐methylbutanal, furfural, and methional), from a model solution onto binderless hydrophobic ZSM‐5 zeolite granules in order to quantify mass transfer parameters and identify bottlenecks. Subsequently, the homogenous solid diffusion model was employed to regress the effective diffusion coefficients for each molecule and experimental condition, which ranged between 10−15 and 10−13 m2 s−1, indicating strong intraparticle mass transfer limitation. Furthermore, it was found that the effective diffusion coefficient is inversely correlated to the molecules' hydrophobicity, expressed as the logD value and its isotherm affinity constant.CONCLUSIONThese results give valuable insight to design and improve the adsorbent material and an off‐flavour removal unit at industrial scale. © 2020 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Reactor Engineering Aspects of the Lateral Flow Reactor

A lateral flow reactor (LFR) is a low pressure drop fixed bed reactor especially suitable for end-of-pipe treatment, for example, the Shell DeNOx system for selective catalytic reduction of NOx. Inherently, an LFR is prone to flow maldistribution, which in turn may negatively affect conversion. A detailed study of the hydrodynamics and overall reactor performance of an LFR is presented. The characterization of the flow patterns is carried out in detail with a 2D computational fluid dynamics (CFD) model. In addition, a “double 1D” hydrodynamic model is developed and validated against the CFD results. This computationally much more efficient model is extended with catalytic reaction kinetics, accounting for intraparticle mass transfer limitations. LFR efficiency can be defined as the ratio of the amount of catalyst needed in a fixed bed with uniform distribution over the amount of catalyst needed in the LFR to reach the same overall conversion. Despite the inherently limited flow uniformity, this efficiency of the LFR remains higher than 95% as long as the flow uniformity is above 50%, that is, for nearly all practical cases.

Effects of Ultrasound on Fermentation of Glucose to Ethanol by Saccharomyces cerevisiae

Previous studies have shown that pretreatment of corn slurries using ultrasound improves starch release and ethanol yield during biofuel production. However, studies on its effects on the mass transfer of substrates and products during fermentation have shown that it can have both beneficial and inhibitory effects. In this study, the effects of ultrasound on mass transfer limitations during fermentation were examined. Calculation of the external and intraparticle observable moduli under a range of conditions indicate that no external or intraparticle mass transfer limitations should exist for the mass transfer of glucose, ethanol, or carbon dioxide. Fermentations of glucose to ethanol using Saccharomyces cerevisiae were conducted at different ultrasound intensities to examine its effects on glucose uptake, ethanol production, and yeast population and viability. Four treatments were compared: direct ultrasound at intensities of 23 and 32 W/L, indirect ultrasound (1.4 W/L), and no-ultrasound. Direct and indirect ultrasound had negative effects on yeast performance and viability, and reduced the rates of glucose uptake and ethanol production. These results indicate that ultrasound during fermentation, at the levels applied, is inhibitory and not expected to improve mass transfer limitations.

A Monte Carlo Method to Quantify the Effect of Reactor Residence Time Distribution on Polyolefins Made with Heterogeneous Catalysts: Part IV—Intraparticle Transfer Resistance Effects

AbstractAn integrated Monte Carlo/polymeric multilayer model (MC/PMLM) is developed to predict the polymer particle size distribution (PSD) and microstructures of polyolefins made with heterogeneous catalysts under intraparticle mass transfer limitations. The Monte Carlo model is used to randomly sample particle sizes and residence times from the catalyst PSD and reactor residence time distribution (RTD), respectively, while the polymeric multilayer model is used to describe single‐particle growth considering intraparticle mass transfer resistances. The effect of reactor RTD, catalyst PSD, and polymerization kinetics on polymer PSD and polymer properties is systematically investigated with the MC/PMLM for the first time. The results show that intraparticle mass transfer limitations under various operating conditions may affect polymer PSD and polymer properties. In addition, due to the versatility of the Monte Carlo approach, the proposed MC/PMLM is adequate to describe complex cases, such as reactor systems with arbitrary RTD and catalyst particles having any PSD.

The effect of hydrothermal impregnation of Ni, Co, and Cu on HZSM-5 in the nitrogen oxide removal

The selective catalytic reduction (SCR) of nitrogen oxides on M/ZSM-5 (M = Cu, Ni, Co) catalysts was investigated. The catalysts were prepared using hydrothermal impregnation of the metal chlorides and nitrates on ZSM-5. The catalysts were characterized by nitrogen absorption/desorption, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible diffusion reflection spectroscopy (UV–Vis DRS), temperature-programmed reduction (TPR), N2O chemisorption and ammonia temperature-programmed desorption. The performance tests for SCR of NO were carried out in a fixed-bed reactor from 250 to 400 °C. During the impregnation, part of the aluminum was eliminated from the zeolite framework due to the acidity of the metal salt solution and heating process as indicated by the reduction in the intensity of XRD peaks and variations in the positions of the FTIR vibrational bands. The Cu(Cl)/ZSM-5 catalyst exhibited NO conversions over 90% over the entire temperature range. The other catalysts showed comparable activities, but the catalysts prepared with chloride salt precursors demonstrated higher activity than those based on nitrate as the precursor. Moreover, the TPR reduction peaks of the metal ion in catalysts prepared with chloride precursor were lower, and their UV–Vis absorption bands revealed bathochromic transfers with higher intensities. Concurrent with these changes, the activity of the catalyst increased. The TPR profiles indicated that Cu and Ni both had an oxidation number of +2, whereas Co was present in the oxidation number of +2 and +3. The mass transfer limitation analysis showed that for particles in millimeter size range or larger significant intra-particle mass transfer limitation would be expected.

Particle size influence on the pore development of nanopores in coal gasification chars: From micron to millimeter particles

The influence of particle size on the growth of nanopores arising from gasification of a South African coal-char was investigated using small angle X-ray scattering. Three different char sizes (75 μm, 2 and 20 mm) were gasified between 800 and 1000 °C to specific conversions up to 50% and the pore development during CO2 and steam gasification was compared. For the CO2 gasified chars studied here, particle size influenced the rates of individual pore growth for all pore sizes and an increased development of micro-, and macropores was observed as particle size increased. For the steam gasified chars studied here, particle size only influenced the rates of individual pore growth for larger pores, with prevalence of macropore development. A novel application of monitoring pore development as a function of distance from the surface was applied to the 20 mm gasified char, spanning the surface to the interior of the spherical particle. The portion closest to the surface, showed the greatest pore development over the entire pore range, followed by the interior and centre. The radial changes in growth rate for individual pore sizes demonstrated intra-particle mass transfer limitations for the 20 mm particle studied here under these conditions.

Effect of mass transfer limitations on catalyst performance during reduction and carburization of iron based Fischer-Tropsch synthesis catalysts

Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously, but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts. In this study, Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method. To investigate the intraparticle mass transfer limitation under reduction, activation and reaction steps, and its effect on catalytic performance, catalyst pellets with different sizes of 6, 3, 1 and 0.5 mm have been prepared. All catalysts were calcined, pretreated and tested under similar conditions. The catalysts were activated in hydrogen (5% H2 in N2) at 450 °C for 3 h and exposed to syngas (H2/CO = 1) at 270 °C and atmospheric pressure for 40 h. Afterwards, FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290 °C, 17 bar and a feed flow (syngas H2/CO= 1) rate of 3 L/h (STP). Using small pellets resulted in higher CO conversion, FT reaction rate and C5+ productivity as compared with larger pellets. The small pellets reached steady state conditions just 20 h after starting the reaction. Whereas for larger pellets, CO conversion, FT reaction rate and C5+ productivity increased gradually, and reached steady state and maximum values after 120 h of operation. The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation. Also the results indicate that some effects of mass transfer limitations in activation step, can be compensated in the reaction step. The results can be used for better design of iron based catalyst to improve the process economy.

Combined single particle growth and population balance modeling in stereoregular polymerization of styrene

Modeling and experimental analysis for syndiospecific polymerization of styrene over silica-supported metallocene catalyst was carried out. A detail model was developed by coupling the single particle growth model (PGM) with particle population balance equation. The model was employed to predict the effects of intraparticle mass transfer limitations and the initial catalyst particle size on the rate of polymerization and the particle size distribution (PSD) of syndiotactic polystyrene (sPS). The single PGM, based on a modified polymeric multigrain model, was first utilized to calculate the single particle growth rate and polymerization rate under intraparticle mass transfer limitations and different initial catalyst particle sizes. Then, the model was solved simultaneously with particle population balance equation to estimate the PSD of sPS under the same limitations. The single PGM results showed a significant radial distribution of styrene concentration across polymer growth. It was further noticed that the diffusion resistance was most intense at the beginning of the polymerization reaction and the effects of polymerization rate were stronger. Moreover, it appeared that increasing the initial catalyst particle size led to lower rate of polymerization. The PSD simulation results revealed that the mass transfer limitation, as well as the initial catalyst particle size made a strong impact on the PSD of sPS. In addition, the simulation results obtained from this model showed good agreement results with experimental data of sPS.

Coupled single-particle growth and kinetics modeling for styrene polymerization over silica-supported metallocene catalyst

A comprehensive mathematical model for styrene stereoregular polymerization was carried out. This model was generated by coupling the single particle growth model (SPGM) with kinetics model, to predict the effect of intraparticle mass transfer resistance and initial catalyst size on the polymerization kinetics. SPGM was derived based on a modified multigrain model (MMGM) to calculate the spatial-time evolution of styrene concentration under intraparticle mass transfer limitations. Then, the SPGM was solved simultaneously with kinetics model to estimate the polymerization rate and molecular weight distribution (MWD) under the above mentioned limitations. The results show that a significant radial distribution of styrene concentration across polymer growing. Moreover, the diffusion resistance was most intense at the early step of the polymerization and the effects of the polymerization rate are more strongly. Additionally, it is appear that increasing the initial catalyst size leads to a decrease in the rate of polymerization. For MWD, the model simulation show that the diffusion resistance led to have an increase in the molecular weight within a period of time similar to the one needed in the catalyst decay. The validation of the model with experimental data given a agreement results and shows that the model is able to predict monomer profile, polymerization rate, and MWD of syndiotactic polystyrene.

A CFD‐PBM‐PMLM integrated model for the gas–solid flow fields in fluidized bed polymerization reactors

AbstractAlthough the use of computational fluid dynamics (CFD) model coupled with population balance (CFD‐PBM) is becoming a common approach for simulating gas–solid flows in polydisperse fluidized bed polymerization reactors, a number of issues still remain. One major issue is the absence of modeling the growth of a single polymeric particle. In this work a polymeric multilayer model (PMLM) was applied to describe the growth of a single particle under the intraparticle transfer limitations. The PMLM was solved together with a PBM (i.e. PBM‐PMLM) to predict the dynamic evolution of particle size distribution (PSD). In addition, a CFD model based on the Eulerian‐Eulerian two‐fluid model, coupled with PBM‐PMLM (CFD‐PBM‐PMLM), has been implemented to describe the gas–solid flow field in fluidized bed polymerization reactors. The CFD‐PBM‐PMLM model has been validated by comparing simulation results with some classical experimental data. Five cases including fluid dynamics coupled purely continuous PSD, pure particle growth, pure particle aggregation, pure particle breakage, and flow dynamics coupled with all the above factors were carried out to examine the model. The results showed that the CFD‐PBM‐PMLM model describes well the behavior of the gas–solid flow fields in polydisperse fluidized bed polymerization reactors. The results also showed that the intraparticle mass transfer limitation is an important factor in affecting the reactor flow fields. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1717–1732, 2012

Experimental Investigation of a CuO/Al2O3Oxygen Carrier for Chemical-Looping Combustion

Chemical-looping combustion (CLC) has emerged as an interesting alternative for conventional power production technologies, intrinsically combining power production and CO2 capture. The performance of the oxygen carrier particles used in this technology is of vital importance for the overall technical and economical feasibility of CLC technology, and therefore, the behavior of a selected oxygen carrier (CuO/Al2O3) has been investigated in more detail using thermogravimetry. The experimental study focused on the reactivity during the oxidation and reduction cycles and the stability of the particles over multiple alternating sequences of these cycles. Particles of relatively large size were used, to investigate the possibility of using the material in packed-bed CLC. Interpretation of the experimental results on a quantitative level was achieved through comparison with numerical simulations using a detailed particle model in which the effects of both reaction kinetics and intraparticle mass-transfer limitations were fully taken into account. It was found that the experimentally determined conversion rate of the particles during oxidation could be very well described by the particle model that accounts for changes in the particle morphology. The average pore size needed in the simulations to reproduce the experimental results matched well with the most common pore size found by nitrogen adsorption−desorption experiments using the BET and BJH methods. For the reduction cycles using hydrogen as the reducing agent, it was concluded that the conversion characteristics could be described reasonably well for moderate conversions, but for higher conversions, the discrepancies were larger, especially at rather low operating temperatures. When reduction cycles were carried out with methane, carbon deposition was observed. The generated data and insights help in assessing the optimal reactor configuration for CLC and its feasibility.

Removal of hydrogen sulfide from a steam-hydrogasifier product gas by zinc oxide sorbent: Effect of non-steam gas components

Removal of H 2S from a steam-hydrogasifier product gas was studied at 636 K and 1 atm using a commercially available zinc oxide sorbent in a packed-bed reactor. A mixture gas containing 22% CH 4, 18.7% H 2, 8.8% CO and 5.5% CO 2 (non-steam components subtotaling to 55%) balanced with steam was used to simulate the steam-hydrogasifier product gas. Sorbent particles of 150–250 μm size were used to eliminate the effect of intraparticle mass transfer limitation. Experiments were conducted to monitor H 2S breakthrough of reactor effluent stream for operation parameters such as space velocity and inlet H 2S concentration. With space velocity varied from 6000 to 8000 to 12,000 h −1 for inlet H 2S concentration in the range of 100–800 ppmv, sulfur capture capacity of the sorbent ( S cap) for 2 ppmv H 2S breakthrough did not change notably, indicating that, for each inlet H 2S concentration tested, sorbent utilization for sulfur removal was not affected by the space velocity. Meanwhile, for each space velocity tested, S cap increased monotonically as the inlet H 2S concentration increased from 100 to 500 to 800 ppmv, which is opposite to the result observed for the mixture gas devoid of CH 4, H 2, CO and CO 2. As the overall content of these non-steam components of the simulation gas was halved for each inlet H 2S concentration tested at 8000 h −1 space velocity, S cap for non-steam gas components of 27.5% content corresponded approximately to the median value of those for the non-steam gas components of 55% and 0% content, suggestive of linear dependency of S cap upon the content of the non-steam components for the inlet H 2S concentration tested.

Coupled Single‐Particle and Population Balance Modeling for Particle Size Distribution of Poly(propylene) Produced in Loop Reactors

AbstractA comprehensive model was developed for the PSD of PP produced in loop reactors. The polymeric multilayer model (PMLM) was first applied to calculate the single particle growth rate under intraparticle transfer limitations. In order to obtain the comprehensive model, the PMLM was solved together with a steady‐state particle population equation to predict the PSD in the loop reactors. The simulated PSD data obtained under steady‐state polymerization conditions agreed with the actual data collected from industrial scale plant. The comprehensive model was also used to predict the effects of some critical factors, including the intraparticle mass and heat transfer limitations, the feed catalyst particle size and the catalyst deactivation, etc., on the PSD.magnified image

Modeling of Multi‐Tubular Reactors for Fischer‐Tropsch Synthesis

AbstractThe results of the simulation of multi‐tubular Fischer‐Tropsch reactors based on a two‐dimensional pseudo‐homogeneous model are presented. The model takes into account the intrinsic kinetics of two commercial iron and cobalt catalysts, intraparticle mass transfer limitations, and the radial heat transfer within the fixed bed and to the cooling medium (boiling water). The effective rate with Co is slightly higher than with Fe. Hence, a temperature level can be used for Co that is 20 °C lower compared to Fe. The conversion and product selectivies are then almost the same and the reactor can be operated safely without a temperature runaway. The results of the simulations are consistent with literature data and show that there is still room for improvement of fixed bed FT reactors, e.g., by an enhanced heat transfer.

Preparation, Characterization, and Performance of HMS-Supported Ni Catalysts for Hydrodechlorination of Chorobenzene

HMS-supported Ni catalysts were prepared by the direct synthesis and the impregnation method. In the direct synthesis, the effect of nickel content and pH value of the preparation system on the catalyst structure and hydrodechlorination performance was systematically investigated. The physicochemical properties of the catalysts were characterized by means of N2 adsorption, hydrogen temperature-programmed reduction, low- and wide-angle X-ray diffraction, hydrogen chemisorption, hydrogen temperature-programmed desorption, transmission electron microscope, and atomic absorption spectroscopy. The catalyst activity in the hydrodechlorination of chlorobenzene was evaluated in a fixed-bed reactor at atmospheric pressure. For the n%Ni(m%)-HMS samples prepared by the direct synthesis method, BET surface area, pore volume, and the pore (2∼5 nm) diameter decrease with increasing Ni content, and the mesostructures becomes worse. When the nickel content exceeds 7.0 wt%, the sample with mesostructures cannot be prepared. This is attributed to the decrease of pH value in the preparation system and the embedment of Ni2+ in the SiO2 matrix. Ni2+ ions highly disperse in the n%Ni(m%)-HMS samples and mainly exist as nickel silicate. After reduction at 450∼650 °C, the metallic nickel particles in n%Ni(m%)-HMS uniformly distribute at about 3 nm. However, for the im−4.1%Ni/HMS sample prepared by the impregnation method, the metallic nickel particles are much larger than those of n%Ni(m%)-HMS. In the hydrodechlorination of chlorobenzene, the n%Ni(m%)-HMS samples show higher activities than im−4.1%Ni/HMS, which can be attributed to the strong interaction between small metallic nickel particles and the support, a greater amount of spilt-over hydrogen, and the acidity of nickel silicate. When the nickel content exceeds 5.9 wt % and the reduction temperature is above 450 °C, there is no remarkable difference in chlorobenzene conversion for n%Ni(m%)-HMS samples. This is perhaps related to the intraparticle mass transfer limitation.

Evaluation of Zeolites in Production of Tetrahydrofuran from 1,4-Butanediol: Performance Tests and Kinetic Investigations

The liquid-phase dehydration of 1,4-butanediol to tetrahydrofuran was investigated over various materials including synthetic zeolites, namely, ZSM-5, Y, Mordenite, Ferrierite, and Beta as well as silica and alumina. The key characters investigated were the Si/Al ratio and cation exchange. The results showed that the ZSM-5 zeolite exchanged with NH4+ exhibited the highest activity in dehydration of 1,4-butanediol. In all tests, nearly 100% selectivity to tetrahydrofuran was observed. After finding the most active catalyst, the kinetics of dehydration of 1,4-butanediol to tetrahydrofuran was studied over this material. The influence of operating parameters such as temperature, pressure, and substrate concentration on reaction was investigated through the Taguchi analysis of experimental data. A strong dependence of reaction rate on temperature was observed. Pressure, however, was found to have a negligible effect on reaction rate. The contribution of external and intraparticle mass transfer limitations on ...

Intrinsic kinetics of continuous growth and ethanol production of a flocculating fusant yeast strain SPSC01

The intrinsic kinetics of continuous yeast cell growth and ethanol production for a self-flocculating fusant yeast strain SPSC01 was investigated by means of mechanically dispersing the flocs and correspondingly established floc size distribution on-line monitoring technique using the focused beam reflectance measurement system, through which the floc intra-particle mass transfer limitation was effectively eliminated, but its ethanol formation metabolism was not affected. Modified kinetic models were developed, which can be used to predict the continuous kinetic behaviors of SPSC01, especially when low dilution rates are applied and limiting substrate concentrations are undetectable and almost all kinetic models developed previously are failed in predicting corresponding kinetic behaviors. Both substrate and product inhibitions reported for freely suspended yeast cell ethanol production were also observed for SPSC01 when high gravity media were fed and relatively high levels of residual sugar and ethanol presented. Model parameters were evaluated through numerical calculation method and validated by experimental data mu = 0.584C(s)/0.155 + C(s) + C(2)(s)/160.7(1 -P/125)(3.68) + 0.004 for growth, nu = 1.998C(s)/0.427 + C(s) + C(2)(s)/366.7(1- P/125)(1.72) + 0.060 for ethanol production These intrinsic kinetic models can be further used to develop the observed kinetic models that quantitatively correlate the impact of the self-flocculating yeast cell size distributions on their apparent rates for yeast cell growth, substrate uptake and ethanol production and optimize the ethanol production process.