Showing papers in "Journal of Chemical Industry and Engineering in 2008"

Dynamical characteristics of methane adsorption on monolith nanometer activated carbon

Abstract: Activated carbon monolith is widely used as adsorbent to enhance the storage capacity of natural gas,which greatly inspires the investigation on adsorption dynamics of methane on this type of adsorbentsThe differential pressure permeation method was used to measure the surface diffusion coefficientThe impacts of Knudsen diffusion,viscous flow and surface diffusion on total diffusion were investigated by using the Maxwell-Stefan model,and the dependence of these impacts on temperature and pressure was also discussedAn empirical correlation was proposed to calculate the surface diffusion coefficientIn the ranges of experiment temperature and pressure,the adsorption dynamic process was dominated by surface diffusion,while Knudsen diffusion was also important at a low pressuresAs the pressure increased,the surface diffusion coefficient approached a constant value,however viscous flow kept continuously rising and contributing an important part to the total flux

Flow and heat transfer characteristics of nanofluids in silicon chip microchannels

Abstract: An experimental investigation was performed on the single-phase flow and heat transfer characteristics through silicon-based trapezoidal microchannels with a hydraulic diameter of 194.5 μm using deionized (DI) water and γ-Al2O3 nanofluids of volume fractions 0.15 % and 0.26% respectively.The effects of Reynolds number,Prandtl number and nanoparticle concentration on the convective heat transfer characteristics were investigated.The results showed that the pressure drop and flow resistance for nanofluids and DI water were approximately the same,but the Nusselt number of nanofluids increased considerably as compared with that of DI water.With the same pumping power,using nanofluids instead of DI water caused the reduction in thermal resistance.It was also found that Nusselt number increased with the increase in nanoparticle concentration,and the heat transfer enhancement was more obvious at the higher bulk temperature of nanofluids.Based on the experimental data,a dimensionless correlation of Nusselt number was proposed.The results presented in this paper help to guide the design of high efficiency integrated chip cooling system.

Measurement of adsorption layer thickness of water reducer by using XPS

Abstract: The adsorption layer thickness of water reducer on the cement surface was measured through the XPS spectrum and the calculating method of XPS information depthThe results showed that the adsorption layer thicknesses of lignosulfonate(LS),modified lignosulfonate(GCL1-T),naphthalene sulfonate formaldehyde condensate(FDN) and aminosulfonate formaldehyde condensate(ASP) on the cement surface were respectively 870 nm,1087 nm,150 nm and 726 nm,while those of GCL1-T and FDN on the fly ash surface were 676 nm and 095 nmThis method could describe the adsorption layer thickness of the water reducer exactlyFrom the results,it could be further concluded that the electric repulsive force was the main factor of the dispersion mechanism of FDN,while the steric repulsive force could not be neglected in the dispersion mechanisms of LS,GCL1-T and ASP

Demonstration of uniformity principle of temperature difference field for one-dimensional heat exchangers

Abstract: The uniformity principle of temperature difference field is a phenomenological principle,which has not been theoretically proved.For one-dimensional two-and three-stream heat exchangers,the extremum principle of entransy dissipation was used to optimize the heat transfer process by variational calculus.It was indicated that the temperature difference field between the hot and cold fluids should be completely uniform if the entransy dissipation reached a minimum for a given heat duty,or if the heat duty reached a maximum for a given entransy dissipation.So,the uniformity principle of temperature difference field of heat exchangers was primarily proved.

Intelligent optimal control based on CBR for fused magnesia production

Abstract: The electro-fused magnesia furnace is one of the main equipment used to produce electro-fused magnesiaAimed at multiple variables, strong nonlinearity and coupling among variables, as well as strong random disturbance of the fused magnesia production process, an intelligent optimal control strategy based on the integration of case-based reasoning and rule-base reasoning was proposedFirst, the technical process of fused magnesia production was introducedNext, the intelligent optimal control strategy including the optimal set model based on rule-based reasoning and the optimal set compensation based on case-based reasoning was discussed in detailFinally,the intelligent optimal control system was developed and successfully applied to a real fused magnesia production processThe proposed intelligent optimal control strategy demonstrated reliable, accurate and timely control performance

Alarm optimization for process industry based on matter-element analysis

Abstract: The alarm points given in process industry are massive and complex that may lead to trouble in monitoring the production.In combination with the characteristics of alarm system and matter-element analysis, a matter-element model was established for each alarm parameter, the correlation function was defined between alarm parameters and alarm levels, the weight certainty was improved based on the correlation function, and the comprehensive correlation function between alarm parameters and alarm levels was calculated.Starting from the premise of safety in production,the alarm parameters were optimized and chosen based on the value of comprehensive correlation function.Then the alarm optimization method for process industry was developed.The provided method was applied to the alarm system of purified terephthalic acid (PTA) solvent dehydration tower.The effectiveness of this method was verified by the result of the above case study.It showed that the alarm optimization based on the matter-element analysis reduced the number of alarms and alarm frequency, and provided a new way to alarm management and operation optimization.

Enhancing influence of Al_2O_3 nano-particles on ammonia bubble absorption process

Abstract: Based on the preparation of the uniform and stable Al2O3 nanofluid,two experimental schemes were developed,which validated that the ammonia bubble absorption effect was enhanced by adding Al2O3 nano-particles into the absorption solution.Two main factors which possibly induce the enhancing absorption effect were found:one was the stability of the nanofluid,the other was the pressure difference between the inlet of the absorber and the gas phase surface in the absorber.In the conditions of sodium dodecyl benzene sulfonate(SDBS)additive,the Al2O3 nanofluid having good stability and enhancing absorption effect could be obtained,although the experimental results showed that the absorption effect of ammonia was restrained by only adding SDBS additive into the absorption solution.Under the bigger pressure difference the Al2O3 nanofluid could represent the enhancing absorption effect at the beginning stage of absorption.With the concentration of ammonia solution increasing,the absorption potential declined,but the enhancing influence induced by the nanofluid was more obvious compared with that with no nanofluid.The possible mechanism of the experimental phenomena was explained.This paper provides a reference for subsequent research on the heat and mass transfer for nanofluid and the thermochemical compressor of the minitype ammonia absorption refrigerator.

Flame image recognition system for alumina rotary kiln burning zone

Abstract: In the rotary kiln alumina production process, because of the complexity and variability of rotary kiln burning zone conditions, some important quality index related process parameters can not be detected continuously on-lineDetecting the different burning zone conditions on-line is a key factor for the whole process automation of alumina industry The current method depends on flame observation by naked eyeIn order to realize automated recognition of burning zone conditions, a method which learned experience and knowledge from naked eye observation was proposed to recognize burning zone conditions by utilizing the image processing technique and pattern classification methodAt first, features were extracted from flame images of rotary kiln burning zone and were combined with some important process parameters to constitute a hybrid feature vectorThen a model with a binary tree based SVM (support vector machine) was constructedAt last, a flame image recognition system was developedThe system was successfully applied to a domestic alumina plant, and good economic benefit was realized

International latest development of automotive air-conditioning system

Abstract: The global warming has attracted comprehensively international attention,and became the main issue of the environment protection.How to decrease the ejection of the greenhouse gas has became the motivity of the development of the automotive air-conditioning system.This paper introduces the development trend of the automotive air-conditioning system,and focuses on the change of the automotive drive power,new refrigerant,the decrease of the refrigerant charge,and the new technology.

Decoupling internal model control for multi-variable non-square system with time delays

Abstract: A new decoupling internal model control(IMC)method was proposed for the multi-variable non-square systems with multiple time delays by introducing the conception of generalized inverse.The traditional IMC based on the inverses of nonsingular matrices was confined to square systems,so the generalized inverse was imported to design the internal model controllers by calculation in frequency domain.Time delays were approximated by the Taylor expansion diagrams.To guarantee the stability and regularity of system,special filters were designed to counteract unstable poles brought forth by the Taylor approximation.The results showed that when the model did not mis-match badly,the output curves had less than 20% overshoot and almost zero deviation from steady state.The output also had good performance about dynamic decoupling,and multiple time delays control.But the control system was sensitive to the change of time delays.Based on IMC system,the response would be better if the model matched more satisfactorily.

Optimization of regeneration recycling water networks with internal water mains

Abstract: A water network with regeneration recycling can reduce freshwater consumption and wastewater discharge to the maximum extent.Networks with internal water mains are normally more flexible,and more convenient to operate and control.In this paper,a general methodology for the design of optimal regeneration recycling water networks with internal water mains was proposed,based on a newly established superstructure.The optimization was virtually a multi-objective problem.Considering the relative importance of these objectives,sequential optimization was adopted.Freshwater consumption,regenerated water flowrate and contaminant regeneration load,were minimized in sequence,which corresponded to three mathematical models.By solving these models step by step,a regeneration recycling water network could be constructed,which was economically favorable.A case study showed the effectiveness of the method.

Temporal and spatial evolution characteristics of two-phase flow pattern based on image texture analysis

Abstract: In order to study the temporal and spatial evolution characteristics of gas-liquid two-phase flow structure,a high-speed dynamic camera was utilized to acquire the dynamic image information of seven typical gas-liquid two-phase flow patterns in vertical and inclined 30° upward pipes with the testing ranges of superficial water velocity 0.02—0.4 m·s-1 and superficial gas velocity 0.005—2.7 m·s-1.The gray level co-occurrence matrix(GLCM)was used to quantitatively characterize 2D information in the local neighborhood of image for analyzing flow pattern image features and the four time-varying characteristic parameter indices which represented image texture structures of different flow patterns were extracted.Then the transition of flow structure in the development process of flow patterns and calculated Lempel-Ziv sequence complexity of the four time-varying characteristic parameter indices were analyzed,and compared with the complexity measurement,fractal scale and recurrence plot determinism calculated by conductance fluctuating signals.The study showed that the dynamic parameter evolution trends of flow pattern image texture structure characteristics described the variation of different flow pattern structures and dynamics complexity,and the correlation index(COR)was more effective to reflect the complexity of flow pattern dynamics than others.It indicated that the proposed dynamic image analysis method was helpful to understanding the flow pattern temporal and spatial evolution characteristics and also was an effective approach to identifying the gas-liquid two-phase flow patterns.

Properties of wheat straw soda lignin of different molecular weights and its influence on properties of LPF adhesive

Abstract: The wheat straw soda lignin (WSSL) was fractionated by means of ultrafiltration, and 3 fractions of different molecular weights were collected.It was shown that with the decrease in molecular weight of WSSL, the content of methoxyl group decreased and the content of phenolic hydroxyl group increased, resulting in increased reactivity of WSSL, while the content of carboxyl group decreased, resulting in increased surface activity of WSSL solution.The results showed that with the decrease in molecular weight of WSSL, the adhesive strength of lignin phenol formaldehyde (LPF) adhesive increased, the formaldehyde content and viscosity decreased, and the comprehensive properties of LPF adhesive were improved.

An approach to using MSPC for power plant process monitoring and fault diagnosis

Abstract: The monitoring and fault diagnosis of large-scale power plant processes that exhibit non-stationary and/or time-varying behavior were discussed. The work considered statistically-based monitoring technique, which was related to the multivariate statistical process control (MSPC) framework. Particular focus is on principal component analysis (PCA), as this technique allows distinguishing between cause and effect variables consequently. To demonstrate the difficulties of monitoring processes with non-stationary and time-varying behavior, the use of conventional PCA was compared with its recursive and fast moving-window counterparts. A recently proposed recursive moving window technique was employed because of its ability in adapting to process changes and its computational efficiency. The advance in fault detection was demonstrated by comparing fast moving-window PCA (MWPCA) with the conventional PCA. In addition, this paper proposes to plot the scaled variables in conjunction with fast MWPCA for fault diagnosis, which proves to be effective in power utility process application.

Time delay estimation of soft-sensor model based on hybrid differential evolution algorithm

Abstract: Time delay estimation is one of the most important issues in system control and signal processingThrough establishing an appropriate fitness function,the time delay estimation of soft-sensor model could be formulated as a multi-dimension nonlinear functional optimization problem,which could be solved by hybrid differential evolution(HDE)algorithmNumerical simulation results on two benchmarks demonstrated the effectiveness and robustness of HDETaking a crude atmospheric distillation unit in oil refinery as an example,a numerical application of the soft-sensor model for the kerosene flash point was madeThe application results demonstrated that the accuracy of soft-sensor model was greatly improved with the introduction of time delay estimationBesides,the effectiveness of the proposed HDE was confirmed

Nonlinear adaptive PID control using neural networks and multiple models and its application

Abstract: For a class of single-input and single-output discrete-time nonlinear systems,a nonlinear adaptive proportional-integral-differential(PID)control method was proposed by using neural networks and multiple models.Such control method was composed of a linear adaptive PID controller,a neural-based nonlinear adaptive PID controller and a switching mechanism.The linear adaptive PID controller was used to guarantee the boundedness of all signals in the closed-loop system,while the neural-based nonlinear adaptive PID controller was employed to improve the performance of the closed-loop system.By introducing a reasonable switching mechanism,the stability of the closed-loop could be guaranteed,while the control performance was improved.Theoretical analysis illustrated that the proposed control method could guarantee the boundedness of all signals in the closed-loop system,while the tracking error would convergent to any given compact set if the structure and parameters of the neural networks were properly chosen.Then the proposed control method was applied to a continuous stirred tank reactor(CSTR).Simulation result of CSTR demonstrated the effectiveness of the proposed control method.Since the proposed control method was based on the incremental digital PID controller,it had a bright application prospect in industrial process control.

Performance simulation and analysis of steam ejector under different operating condition

Abstract: Numerical simulation model of steam ejector was established by application of the modified thermal dynamic method.The performance variation under different operating condition was calculated for the steam ejector used in thermal vapor compression desalination system coupling with the subroutine of thermo-dynamics of water and steam.The effects of motive steam pressure,suction pressure and mixed vapor pressure on entrainment ratio were analyzed.The results of the simulation indicated that entrainment ratio decreased with increasing compression pressure when compression pressure exceeded design value,and entrainment ratio maintained at a constant value when compression vapor pressure was lower than design value.The increase of suction pressure could improve the performance of steam ejector.Steam ejector performance would worsen when the pressure of motive steam was different from the design value.The decrease(lower than design point)or increase(higher than design point)of motive steam pressure resulted in worsened performance of steam ejector.

Solubilities of two kinds of imidazolium ionic liquids for fir powder

Abstract: Two kinds of ionic liquids,1-(2-hydroxylethyl)-3-methyl imidazolium chloride([HeMIM]Cl)and 1-allyl-3-methyl imidazolium chloride([AMIM]Cl)were synthesized,and the chemical structures of the ionic liquids were confirmed by FT-IR and NMR spectrum.The solubilities of the ionic liquids for fir powder activated with different concentrations of NaOH were studied respectively.The chemical structure and crystalline form of fir powder before and after dissolution were analysed by FT-IR and XRD.It showed that the ionic liquids all had a good solubility for cellulose in activated fir powder,and the solubility of [HeMIM]Cl was better than that of [AMIM]Cl.When the concentration of NaOH to activate fir powder was 25%,the solubility was the best,and the crystallinity of the regenerated cellulose after dissolution decreased.

Cloning and prokaryotic expression of β-glucuronidase from Penicillium purpurogenum Li-3

Abstract: One new gene of β-glucuronidase (EC 32131) which could biosynthesize glycyrrhetinic acid monoglucuronide(GAMG)from glycyrrhizin,was cloned from Penicillium purpurogenum Li-3 by degenerated PCR using primers designed from the conserved amino acid sequencesIt is the first time that a β-glucuronidase gene (pgus) (GenBank Accession NoEU095019) was cloned from Penicillium species other than Penicillium canescensSequence analysis indicated that the gene of pgus has 1815 base pairs,encoding 604 amino acids with the putative potential molecular weight of 667×103 and 4 potential N-glycosylation sitesThe prokaryotic expression system was constructed with pET-28a (+),as the vectorThe fusion protein(PGUS-E)with activity was overexpressed in Ecoli BL21 (DE3) after IPTG inductionThe specific activity of enzyme,purified with Ni2+-NTA column to homogeneity (accounting for 95% of soluble protein),was up to 6368 U·mg-1The production of soluble PGUS-E was about 256 mg·L-1 culture mediumThe molecular weight of sub-unit was estimated to be about 70×103 by SDS-PAGE

Effect of atomization on membrane structure and characteristics during manufacture of polymer-coated controlled-release fertilizer

Abstract: Controlled-release membrane was prepared based on the phase inversion method in which circulated urea particles were coated with polyethylene and olefin dispersed in tetrachloroethylene solution.The effect of atomizing on the membrane structure and nutrients release characteristics was investigated systematically.The results showed that as atomizing diameter changed from 43 μm to 120 μm, the average pore diameter of membrane increased from 25.1 nm to 149.2 nm, thus, the release duration of nitrogen coated-urea dropped from 360 d to 96 d consequently.Atomizing diameter played an important role in the structure and characteristics of the membrane and atomizing influenced the membrane formation during phase inversion, therefore, nitrogen release rate of controlled-release urea was manipulated by the mini-pore structure of membrane.Furthermore, in order to obtain satisfactory release, the atomizing diameter should be optimized around 40—120 μm , and the ideal average diameter of the membrane pores should be in the range of 50—150 nm.

SPM-based online fault prediction approach for multivariate continuous processes

Abstract: Fault prediction for a class of unknown-model multivariate continuous processes with a hidden fault was studied,and a solution was given based on statistical process monitoring(SPM)approach.A principle component analysis(PCA)model using sample data under normal state was built,then the characteristic value for fault prediction was constructed,and time series analysis and prediction were applied to the characteristic value to predict the remaining useful life(RUL)of the system.Aiming at the linear time invariant system,a characteristic value was proposed and the prediction error of RUL was analyzed under some assumptions for system structure and hidden fault.A case study on a CSTR showed the efficiency of the proposed approach.

Particle residence time distributions in entrained-flow gasifier

Abstract: The particle residence time distributions in the entrained-flow gasifier as the important parameters in the gasification process were studied by using a new stimulus response method.The differences of the particle residence time distributions in the opposed multi-burner entrained-flow(OMBEF) and Texaco gasifier were compared.The influence of gas velocity and particle diameter on particle residence time distributions was discussed.The experimental results showed that the new stimulus response method was reliable and could be used to measure the particle residence time distributions in the entrained-flow gasifier and the particle residence time in the OMBEF gasifier was more favorable than in the Texaco gasifier.The results also showed that with increasing gas velocity and decreasing particle diameter,the mean and variance of particle residence time increased in both kinds of entrained-flow gasifier.

Numerical simulation of dense pneumatic conveying of pulverized coal in horizontal pipe at high pressure

Abstract: A new frictional-kinetic model for dense phase pneumatic conveying of pulverized coal in a horizontal pipe at a high pressure was establishedThis model treated the kinetic and frictional stresses of particles additivelyThe kinetic stress was modeled by using the kinetic theory of granular flowThe friction stress proposed by Srivastava et alwas modified to account for dense phase pneumatic conveyingThe simulation results included profiles of gas and particle phase axial velocity,profiles of solids concentration,profiles of the turbulence intensity of gas and particle phase,as well as the value of pressure gradientThe formation and motion process of the settled layer were verifiedAn experiment was also carried out to validate the accuracy of the simulation results,which showed that the predictions of pressure gradient were in good agreement with the experimental data

A Model Based on Two-Fluid Theory for Predicting Hydrodynamic Behavior in 3D Fluidized Bed: I. Homogeneous and Bubbling Fluidization of Gas-Solid Systems

Abstract: A mathematical model,including additional terms in both the gas-and solid-phase momentum equations based on the two-fluid theory by considering particle-fluid interactions under a quasi-equilibrium state,was employed to explore homogenous fluidization of Geldart A particle and bubbling/collapsing fluidization of Geldart B particle in 3D gas-fluidized beds.The main features of this model are that the characteristic length in the model is of the order of the particle diameter and only a correlation for drag force coefficient is necessary to close the governing equations.Transient calculations within the bed of 0.2 m(long) × 0.2 m(wide) × 0.5 m(high) were conducted in the platform of a commercial software package,CFX 4.4,by adding user-defined Fortran subroutines.To verify the mathematical model and numerical procedure,two kinds of Geldart A particles were simulated at superficial gas velocity of umf and 1.5umf,and the results showed homogenously expanding behavior in nature.Then the effect of disturbances on local voidage and solid velocity profile at the grid scale,and overall bed pressure drop at the equipment scale were investigated numerically for two kinds of Geldart A particles.Bubbling and collapsing behavior at the grid scale,and overall bed pressure drop during bubbling process and averaged bed height and the standard deviation of the interface during the collapse process at the equipment scale were probed for one kind of Geldart B particles.The above numerical simulations were in fair agreement with the classic theory of Geldart,experiment and simulation in the literature,indicating that this model can be used to predict homogeneous fluidization of Geldart A particles and bubbling and collapsing behavior of Geldart B particles in 3D fluidized beds.

Soft sensor modeling based on DE-LSSVM

Abstract: Soft sensing technique is an effective method to estimate variables which are difficult to be measured on-line in industrial processes, and the core problem of soft sensing technique is construction of an appropriate mathematical model.Support vector machine (SVM) algorithm is a machine learning method based on statistical theory.Least squares support vector machine (LSSVM) is a development of the SVM, and has a faster velocity than the standard SVM.Similar to SVM, LSSVM also has the problem of parameter selection.The differential evolution (DE) method was proposed to select hyper-parameter of LSSVM.At last DE-LSSVM was presented for soft sensor modeling on testing the content of 4-carboxybenzaldehyde (4-CBA) in terephthalic acid, and the result was satisfied.

Effect of process conditions of interfacial polymerization on performance of reverse osmosis composite membrane

Abstract: Reverse osmosis composite membrane was prepared by interfacial polymerization(IP)of metaphenylene diamine(MPD)with trimesoyl chloride(TMC)on the surface of polysulfone(PS)supportThe effects of monomers concentration,reaction time of IP,time and temperature of heat treatment on the separation performance of composite membranes were investigatedThe influences of phase-transfer catalyst(PTC)on the separation performance of composite membrane were also studied,and the mechanism of reaction process was discussedFrom the orthogonal experiment results,the optimum conditions were the concentration of TMC and PMD 3 g·L-1,20 g·L-1 respectively,and the temperature and time of heat treatment 90 ℃ and 15 min,and the flux of 1491 L·m-2·h-1 as well as rejection of 0951(pressure 16 MPa,temperature 25℃,concentration of NaCl 20000 mg·L-1)were obtained under these conditionsIn addition,it was found that at a low concentration of MPD,the separation performance of composite membrane could be remarkably improved by adding PTC into the water phase

CFD modeling of heat transfer in fixed bed reactors

Abstract: Fixed bed reactors(FBRs)have been widely used in chemical and bio-chemical processes.However,local flow and heat transfer in fixed bed reactors have challenged researchers for a long period.Although the effective parameter methods have been applied extensively to modeling local heat transfer in fixed beds,the general validity of effective parameters modeling is still questionable due to the lack of full understanding of local temperature fields in fixed beds.The computational fluid dynamics(CFD)technique is a new alternative to experimental approaches to investigate flows and heat transfer in fixed beds.It numerically solves the flow and/or transport governing equations and obtains local information like flow and temperature fields.In contrast to the averaged values acquired with the conventional theoretical and experimental methods,the results of CFD simulation are accurate local distributions of velocity,pressure,temperature,specie concentration and so on.The latest work and progress in the field of CFD modeling of heat transfer in fixed bed reactors were reviewed and analyzed,and also the perspectives of CFD application in fixed bed modeling were discussed.

Combined cycle of air separation and natural gas liquefaction

Abstract: An integrated process for air separation and liquefaction of natural gas was presented,and based on such an original idea a novel combined-cycle using nitrogen expansion refrigeration unit and producing LNG in addition to nitrogen and oxygen was proposed.Process simulation and second law analysis were performed to reveal the influence of flow rate ratio through expanders β on heat transfer temperature difference and consequent exergy loss,and thus the optimal β under different operation conditions was obtained.Hence,the change of temperature difference distribution and exergy loss in the heat exchanger could be investigated conveniently and effectively through the principle of exergy analysis in combination with energy composite curves.Such information is valuable for optimal design of practical cryogenic systems.

Melt index prediction of polypropylene based on SNNs-RR

Abstract: Melt index prediction of polypropylene based on stacked neural networks-ridge regression (SNNs-RR) was studied.Single neural network model generalization capability could be significantly improved by using the stacked neural network model.Proper determination of the stacking weights was essential for good SNNs model performance, the determination of appropriate weights for combining individual networks using ridge regression was proposed.The results of using SNNs-RR model demonstrated significant improvement in model accuracy and robustness, as compared with using the single neural network model.

Carbonation reaction characteristics of dry potassium-based sorbent for CO_2 capture

Abstract: The carbonation reaction characteristics of potassium-based sorbent was investigated with thermogravimetric apparatus(TGA),X-ray diffraction(XRD),scanning electron microscopy analysis(SEM)and N2 adsorption method.The results showed that the carbonation rate of analytical reagent(AR)K2CO3 was rather slow with its composition of K2CO3·1.5H2O.The carbonation rate of the K2CO3 sample without crystal water was also slow,because K2CO3 could react quickly with H2O from atmosphere to produce K2CO3·1.5H2O.However,the conversion rate of the sample reached 85% within 20 minutes,when K2CO3 was provided by decomposition of KHCO3.The sample still kept high activity after several cycles.The different reaction behavior of these samples were analyzed from the microscopic view.And the reaction mechanisms of these samples were discussed.Also the empirical equations of the reaction rates and the kinetic parameter were obtained by the thermal analysis method.The present work has provided the data base for the technology of dry potassium-based sorbent capturing of CO2.