Potassium Carbonate Concentration Research Articles

Single step calcium sulfate scale removal at high temperature using tetrapotassium ethylenediaminetetraacetate with potassium carbonate

Calcium sulfate (CaSO4) scale has been identified as one of the most common scales contributing to several serious operating problems in oil and gas wells and water injectors. Removing this scale is considered an economically feasible process in most cases as it enhances the productivity of wells and prevents potential severe equipment damage. In this study, a single-step method utilizing potassium carbonate and tetrapotassium ethylenediaminetetraacetate (K4-EDTA) at high temperature (200 °F) has been used to remove CaSO4 scale. The CaSO4 scale was converted to calcium carbonate (CaCO3) and potassium sulfate (K2SO4) using a conversion agent, potassium carbonate (K2CO3), at a high temperature (200 °F) and under various pH conditions. Various parameters were investigated to obtain a dissolver composition at which the optimum dissolution efficiency is achieved including the effect of dissolver pH, soaking time, the concentration of K4-EDTA, the concentration of potassium carbonate (K2CO3), temperature impact and agitation effect. Fourier transform infrared, X-ray crystallography, ion chromatography, stability tests and corrosion tests were carried out to test the end product of the process and showcase the stability of the dissolver at high temperature conditions. A reaction product (K2SO4) was obtained in most of the tests with different quantities and was soluble in both water and HCl. It was observed that the dissolver solution was effective at low pH (7) and resulted in a negligible amount of reaction product with 3 wt% CaSO4 dissolution. The 10.5-pH dissolver was effective in most of the cases and provided highest dissolution efficiency. The reaction product has been characterized and showed it is not corrosive. Both 7-pH and 10.5-pH dissolvers showed high stability at high temperature and minimum corrosion rates. The single step dissolution process showed its effectiveness and could potentially save significant pumping time if implemented in operation.

Design and synthesis of new series of 3‐cyanopyridine and pyrazolopyridine derivatives

AbstractReaction of 3‐cyano‐4,6‐dimethyl‐2‐pyridone with ethyl chloroacetate afforded ethyl 2‐([3‐cyano‐4,6‐dimethylpyridin‐2‐yl]oxy)acetate 2 and ethyl 2‐(3‐cyano‐4,6‐dimethyl‐2‐oxopyridin‐1[2H]‐yl)acetate 3, the reaction product yield depend on the reaction condition (potassium carbonate concentration and reaction time). These compounds used as precursors to synthesize pyridine derivatives 4, 6‐10, 15, 17‐20, furopyridines 5, 16, pyrazolopyridine 12, pyridopyrazolopyrimidines 14a,b. The structure of the newly synthesized compounds was confirmed by spectral data (IR, NMR, and mass spectra) and elemental analysis.

Thermodynamic and kinetic properties of NH3-K2CO3-CO2-H2O system for carbon capture applications

An innovative solvent based on the quaternary system CO2-NH3-K2CO3-H2O is reported and characterized in terms of its thermodynamic properties and rate of CO2 absorption. Thermodynamic properties of the solvent such as vapor-liquid equilibrium, solid-liquid equilibrium, and the heat of desorption were modelled with the Extended UNIQUAC thermodynamic model. The kinetics of CO2 absorption in the solvent were studied experimentally with a wetted wall column set-up. The absorption rate was investigated with respect to temperature, ammonia concentration, potassium carbonate concentration, and CO2 loading, under the typical operating conditions of a capture plant. Globally, the solvent has a number of interesting properties for CO2 capture applications. Indeed, adding K2CO3 to the ammonia solvent reduced both the ammonia slip and the heat of desorption. Experimental analysis showed that the kinetics of absorption were mainly influenced by the reaction between free ammonia and CO2. Hence, the overall mass transfer coefficient decreased when increasing the K2CO3 content of the solvent.

Phase Equilibria in System KHCO3–K2CO3–H2O at 25°C

Phase equilibria in ternary water–salt system \(\left. {{{\rm{K}}^ + }} \right\|\;{\rm{CO}}_3^{2 - }\), \({\rm{HCO}}_3^ - - {{\rm{H}}_2}{\rm{O}}\) at 25°C were studied by a combination method. A limited solid solution series was found to form; the reasons behind the scatter of the reported compositions of the chemical compound were elucidated. The behavior of the limited solid solution series in response to increasing potassium carbonate concentration in saturated solution was studied.

Experimental and Theoretical Study of CO2 Absorption with Piperazine-Promoted Potassium Carbonate Solution in Hollow Fiber Membrane Contactors

Potassium carbonate is an economical absorbent for CO2 separation from flue gases. In this study, potassium carbonate as absorbent and piperazine as promoter were applied to absorb CO2 from a gas mixture using a hollow fiber membrane contactor in experimental scale. Also, a mathematical model has been presented to find the CO2 concentration profile in different phases and to analyze the process. Effects of concentration of potassium carbonate and piperazine and other parameters such as liquid and gas flow rates were experimentally observed and studied. Effects of membrane wetting on absorption recovery and piperazine concentration on effective length of the module have been analyzed using the mathematical model. Experimental results show that CO2 recovery can rise up to 1.6 times and CO2 recovery can reach to 90% by adding 0.03 M piperazine to 5 wt % aqueous solution of potassium carbonate. The results of the mathematical model at high gas flow rates reveal that CO2 recoveries are considerably higher (up ...

Mathematical modeling and optimization of carbon dioxide stripping tower in an industrial ammonia plant

In the present study, performance of an industrial regeneration tower has been examined and validated for stripping of carbon dioxide from diethanolamine (DEA)-promoted hot potassium carbonate solution. The applied model employs a comprehensive non-linear rate-based method to take into account the coupling between material and energy balances, thermodynamic vapor-liquid equilibrium (VLE) relations and chemical kinetics. VLE relations are used to model the flash section located on the top of tower. The penetration theory provides an appropriate desorption rate and enhancement factor for the chemical desorption which incorporates an extensive set of important reactions. The model predictions were compared with the operating data obtained from ammonia plant of a petrochemical complex. The impact of parameters such as steam temperature, potassium carbonate concentration, inlet temperature of rich solution, promoter concentration and column pressure on the tower performance have been examined and optimized. Acceptable agreements have been attained between the simulation and measured industrial data. The optimum conditions were found to be 2.5wt%, 1.6 barg, 401 and 378K for promoter concentration, column pressure, steam temperature, and inlet temperature of rich solution which demonstrate a good compatibility in comparison to optimum operational conditions.

Adsorption Separation of CO2/CH4 Gas Mixture on Carbon Molecular Sieves Modified by Potassium Carbonate

In order to improve the separation performance of CO2/CH4 on carbon molecular sieves (CMS), CMS was modified by metal in this study. The surface of CMS had −OH, which could provide a great support for the chemical modification. In this paper, different metal ions, precursors of potassium, loading concentration of potassium carbonate (K2CO3), and calcination temperature were investigated for CO2/CH4 separation. Results showed that CMS loaded with K2CO3 and calcined at 773–873 K was the best for CO2/CH4 separation. Compared with the untreated CMS, the adsorption capacity of CO2 for the best adsorbent increased from 1.15 to 1.72 mmol·g–1 and the value of separation factor increased from 1.9 to 2.75 mmol·g–1. The K2CO3 treatment was effective in generating metal oxide K2O and KO2, which could facilitate the adsorption of CO2 after K2CO3/CMS being calcined. However, the reaction between CH4 and metal was weak. In summary, K2CO3/CMS was proved to be one of the candidates for CO2/CH4 separation.

Fabrication and evaluation of an electrodialytic carbonate eluent generator for ion chromatography

An electrodialytic potassium carbonate eluent generator and its associated potassium bicarbonate eluent generator have been fabricated for ion chromatography (IC). The device can withstand high backpressure up to ∼32MPa and no observable leakage under such pressure is found during 2h. In the range of 0–13.7mM, potassium carbonate concentration can be generated linearly with the applied current with a slope that is essentially Faradaic. At least 10mM potassium carbonate can be online changed into 10mM potassium bicarbonate via a potassium bicarbonate eluent generator, which offers an easy way to manipulate the separation selectivity. When coupled with IC system, the device demonstrated good reproducibility indicated by less than 0.52% of the relative standard deviation of the retention times.

Response Surface Modeling for Optimization of Textural and Color Characteristics of Dried Grapes

Abstract This study presents the optimization of pre-drying treatment and storage conditions on textural and color properties of dried grapes using a response surface methodology – central composite rotatable design. Effects of three variables, potassium carbonate concentration (K2CO3, 5.98–11.02%), storage temperature (3.18–36.82°C), and relative humidity (RH, 6.96–91.04%), were evaluated. The response variables were defined as the rupture force, deformation, and Hunter L, a, and b values of dried grapes. Second-order empirical relationships with high R 2 (>0.96) values between the responses and independent variables were derived. Results also showed that the K2CO3 concentration and temperature were the most significant factors influencing the studied textural and color characteristics, respectively. The overall optimum region resulted in the desirable characteristics was predicted at a combined level of 9.27% K2CO3 concentration, 4°C storage temperature, and 67.34% RH. Under these conditions, the corresponding predicted response values for the rupture force, deformation, and Hunter L, a, and b values of dried grapes were 2.15 N, 2.53 mm, 28.54, 3.25, and 9.74, respectively. The predicted values thus obtained were close to the actual values indicating suitability of the models.

Effect of Potassium Carbonate (K2CO3) on the Viscosity and Related Physico – Chemical Properties of Genger (Bombax costatum) Powder during Storage

Effect of storage and concentration of potassium carbonate (K2CO3) on the viscosity and related physico – chemical properties of genger (Bombax costatum) powder was determined. Genger powder was stored for a period of four (4) months (May-August) at 30oc ± 5oc under varying concentrations of K2CO3: 0%, 5%, 10% and 15% in two containers (plastic, giving samples A – D and metal tins, giving samples A1 – D1). Thereafter, the moisture and crude fat contents, water absorption capacity, least gelation concentration, effect of K2CO3 concentration on gel strength and viscosity of the stored powders were determined, using standard methods of analysis, with fresh powder (analyzed before storage) as control. Moisture content decreased significantly (p < 0.05) from 8.37% to 3.04% and 2.00% in samples D and D1 respectively, while crude fat content increased significantly (p < 0.05) from 2.50% to 7.50% and 10.05% in the same samples. Water absorption capacity also increased significantly (p < 0.05) from 6.4g/g to 6.40g/g in the fresh sample to 7.30g/g and 8.30g/g in samples D and D1 respectively. Gelation capacity increased considerably, with 15% K2CO3 giving very strong gels at 1.50% concentration. The overall viscosity increased significantly (p < 0.05) with increase in concentration of (K2CO3) from 64.00FN to 110.00FN after storage. Generally, samples stored in metal tin gave better results than those in the plastic container.

Perbaikan Mutu Bubuk Kakao Melalui Proses Ekstraksi Lemak dan Alkalisasi

“This study aimed to investigate the possibility of reducing the fat content of cacao powder by using organic solvent extraction and to improve the cacao powder quality that meets the quality standard and market requirement. The research was carried out at the University of Syiah Kuala from September 2007 to November 2007. Fermented cacao beans as raw material for the research were collected from farmers in Seureuke, Aceh Utara. Cacao fat was extracted from the powder by pressing them at high pressure. Remaining fat in the powder was further reduced by organic solvent extraction to approximately 4 percent to meet the Indonesian National Standard (SNI). The cacao powder was alkalized with variation treatments of potassium carbonate concentration of 2.0, 2.5 and 3.0 percent and alkalization time of 15, 30 and 45 minutes. The experiment was designed according to randomized factorial design with three replications.Alkalization had affected pH and solubility of cacao powder significantly. pH of the powder increased proportionally as followed the function of y=0.35x + 5.00. The effect of alkalization to the solubility was quadratic with a function of y= -16.34x2 + 76.93x – 60.60. The maximum solubility of 30% was reached at the concentration of potassium carbonate of 2.35%.The alkalization affected the colour hue L* of the cacao powder. Addition of potassium carbonate and time of alkalization had a significant effect but no effect on the interaction. The effect of potassium carbonate and time of alkalization followed the function of y= -4.39x + 42.17 and y= -0.13x + 35.17 respectively. Aroma of alkalized cacao powder was better than commercial products from the market. This had been investigated by panellist consisting of 20 people.

The Effects of Different Dipping Solutionsand Storage Conditions on the Colour Properties of Raisin

In this study, we survey about the effect of pretreatment on the sultana (Raisin) color. We use from three kinds of solutions, 0, 5 and 10% of potassium carbonate salt and 5 % of Pakistan oil for pre treating. Dried grapes are stored at three levels of temperature (4°, 18° and 32°C) with three relative humidity. Relative humidity gets from saturated solution of potassium carbonate salt, potassium acetate and sodium chloride salt. We assess the color of samples in (2, 5 and 8 months) by Hanterlab. Color analysis indicates that the factors are studied (chemical pretreatment, temperature, keeping time) affect on color of raisins indexes. During keeping time the lowest index L pertains to those samples which are kept at 4°C and by increasing keeping temperature index L decreases and index a/b increases. A/b index will decrease when the concentration of potassium carbonate in emulsion increase and therefore color will be brighter.

Microwave assisted acetylation of mung bean starch and the catalytic activity of potassium carbonate in free‐solvent reaction

AbstractMung bean starch acetate has been successfully produced with transesterification reaction of the starch under microwave assistance using vinyl acetate (VAC) as esterifying agent and potassium carbonate (K2CO3) as a catalyst. Various concentration of potassium carbonate (0–0.117 mmoleq/AGU) was resulted in starch acetate with increased mood of the degree of substitution (DS = 0.003–0.27) in a short time. An increase in the degree of substitution, resulting in increase of the peak intensity of ester carbonyl group (CO) at 1742 cm−1, which was further proved by FTIR. Obvious change in the starch granules morphology, increasing in the hyrophilicity and decreasing in the temperature and enthalpy of gelatinization were noticed accordingly to the degree of the starch modification. The X‐ray pattern of native starch was A type, with similar pattern in modified derivatives.

Catalytic pyrolysis of Phragmites (reed): Investigation of its potential as a biomass feedstock

In this paper, thermogravimetry, TG, and pyrolysis are used for the thermochemical evaluation of the common reed (Pragmites australis) as a candidate biomass feedstock. The TG analysis indicated that the material loses 4% of its weight below 150°C through dehydration. The main decomposition reaction occurs between 200 and 390°C. The rate of weight loss, represented by the derivative thermogravimetric, DTG, signal indicated a multi-step reaction. Kinetic analysis helped in the resolution of the temperature ranges of the overlapping steps. The first step corresponds to the degradation of the hemi-cellulosic fraction and the second to the cellulosic fraction degradation. The TG and DTG signals of reed samples treated with increasing concentration of potassium carbonate (0.6–10wt%) indicated a catalytic effect of the salt on reed decomposition. The temperature of maximum weight loss rate, DTGmax, exponentially decreased with increasing catalyst content, whilst the initial temperature of the decomposition decreased linearly. The pyrolysis studies were carried out in a Pyrex vertical reactor with sintered glass disc to hold the sample and to aid the fluidization with the nitrogen stream flowing upwards. The reactor was connected to a cyclone and condenser and a gas sampling device. Tar and char are collected and weighed. The gas chromatographic analysis of the evolved gases demonstrated the effect of pyrolysis temperature (400, 450, and 500°C) on their composition. The temperature increase favors the yields of hydrocarbons, carbon monoxide and hydrogen at the expense of methanol and carbon dioxide. Similarly, reed samples treated with K2CO3 at 10wt% were pyrolyzed and analyzed. Comparisons for the various parameters (yields, gas composition and carbon–hydrogen recovery) between the untreated and catalyzed reed conversion were also made.

Pd-Supported Catalysts: Evolution of Support Porous Texture along Pd Deposition and Alkali-Metal Doping

Adsorption of N2 at 77 K and scanning electron microscopy have been used to measure the changes in the support morphology, at nano- and microscale level, along the processes involved in the preparation of a supported Pd catalyst: Pd deposition, doping, and thermal treatments. Among the investigated supports, viz., activated carbons, gamma-Al2O3, SiO2, and SiO2-Al2O3 (SA), the SA one was found particularly sensitive to these processes, as a result of its high plasticity and reactivity. Involved processes can be summarized as follows: (i) During the Pd deposition, the support itself is partially dissolved and removed as a result of both the basicity of the precipitating agent and the final washing. (ii) When the undoped sample is thermally treated up to 823 K, only modest phenomena are observed. (iii) Upon doping with potassium carbonate, the support dissolution continues, and the greater the carbonate concentration, the greater the dissolution extent. In this case the dissolved material is not removed, but reprecipitates (partially outside the pores), during the subsequent drying at 393 K. (iv) When doped samples are thermally treated, the reaction between carbonate and support causes the mobilization of the support itself, with sintering phenomena that can reach the total collapse of the porous structure. The starting temperature of the pore collapse decreases with increasing potassium carbonate concentration. The modification of the support influences, directly or indirectly, the surface properties and the availability of Pd particles that can be doped or even covered by materials from support and made more or less accessible or even inaccessible by pore narrowing, widening, or blocking.

CO 2 transfer in an aqueous potassium carbonate liquid membrane module with dense polymeric supporting layers: Influence of concentration, circulation flow rate and temperature

Gas–liquid separation systems have already received considerable attention in a great number of situations of industrial interest. The attention paid to membrane contactors and immobilized liquid membranes have recently increased due to their separation performances. For the sake of simplicity, most experiments are usually performed at room temperature. It is, however, obvious that increasing the temperature would increase the reaction rate and thereby also possibly enhance the system's productivity. This work presents a systematic study of CO 2 and H 2 transport in a novel flowing liquid membrane (FLM) module with dense membranes separating layers and aqueous potassium carbonate (concentration 0.1–3 kmol/m 3) solutions in the temperature range 295–353 K. A model of CO 2 transport with reversible chemical reactions through the FLM was developed and compared to a series of experimental data. It was found that increasing the concentration of potassium carbonate as well as the temperature led to large increases in both the CO 2 productivity and the CO 2/H 2 selectivity. The industrial implications of these observations were discussed. Unsteady state transport of CO 2 was also investigated and a simple model of gas transfer in the FLM with physical absorption in the liquid phase was developed.

Gas transport in combined membrane system with moving liquid carrier

The study of selective membrane valve (SMV)—the membrane system which consists of two polymeric membranes and a layer of liquid between them (moving or non-moving) is presented in this paper. Permeability of pure gases such as oxygen, carbon dioxide and hydrogen are investigated. Distilled water and aqueous solutions of potassium carbonate were used as liquid carriers. Aqueous potassium carbonate was used as chemical absorbent of carbon dioxide. The dependencies of gas transport parameters of SMV on water flow rate and potassium carbonate concentration have been obtained. Two models of gas transport in membrane system were developed. A first model describes SMV with flowing physical liquid absorbent, the second one—with non-moving chemical liquid absorbent. The first model was found to be in good agreement with experimental results for hydrogen. Carbon dioxide permeability through SMV with potassium carbonate aqueous solution is well described by the second model. The increasing of the time-lag of non-steady state permeability process of carbon dioxide when concentration of chemical absorbent increases was also demonstrated by the second model.

Analysis of CO 2 removal by hollow fiber membrane contactors

A numerical analysis was performed to investigate the removal behavior of carbon dioxide using a hollow fiber membrane contactor in which an aqueous potassium carbonate solution flows as an absorbent. An important feature is the inclusion of the nonlinear reversible reaction terms that result from the reactions between the absorbent solution and carbon dioxide. The coupled nonlinear partial differential equations were derived and solved numerically, which describe either the absorption or desorption of carbon dioxide in a membrane contactor. In a numerical analysis, the absorbent liquid always flows through the inner side of the hollow fiber in both absorption and desorption steps. The analysis includes the effects of the pressure of feed gases and the extent of vacuum, the absorbent flow rates, the concentration of potassium carbonate in an absorbent solution, the diameter and length of the fibers. One important result is the determination of the optimal absorbent flow rate such that it is saturated just at the exit of the contactor.

Separation of isopropanol from aqueous solution by salting‐out extraction

AbstractA novel salting‐out extraction process has been developed to separate isopropanol from aqueous solution. Potassium carbonate was experimentally shown to be effective in modifying the liquid–liquid equilibrium (LLE) of an isopropanol/water/hexane system in favour of the solvent extraction of isopropanol from an aqueous solution with hexane, particularly at suitable salt concentrations. Potassium carbonate enlarged the area of the two‐phase region. This effect essentially increased the distribution coefficient of isopropanol between hexane and water and increased the separation factor for isopropanol vs water, which is an important consideration in designing a solvent extraction process. The effects of potassium carbonate concentration, temperature and pH on the LLE were studied. Finally, a ϕ30 mm × 1200 mm reciprocating plate column (RPC) was tested to separate isopropanol from an aqueous solution. When isopropanol in an aqueous solution with composition of isopropanol/water = 1:0.95 (wt/wt) was extracted by hexane assisted with 30% (wt%) potassium carbonate aqueous solution, the alcohol–water ratio increased to 11:1 in the extract.© 2001 Society of Chemical Industry

通常濃度のシアン化銀浴からの厚付け銀めっき

Heavy electrodeposition of silver from conventionally concentrated cyanide baths was studied in terms of bath composition, the range of appropriate current densities and cathodic polarization curves.It was found that the orientation indexes of silver deposits approached unity when the molarity ratio of KCN to AgCN was 5, and the appropriate range of potassium carbonate concentration varied with the molarity ratio of KCN to AgCN. Both potassium hydroxide and potassium carbonate must be added to baths for heavy silver electrodeposition. The appropriate range of potassium carbonate concentration increased with increases in the concentration of potassium hydroxide. Cathodic polarization also increased with increases in the concentration of potassium carbonate, but changed little with the addition of potassium hydroxide. The recommended conditions for heavy electrodeposition of silver in cyanide solutions with conventional concentration are AgCN: 40g/L, KCN: 98-107g/L, K2CO3: 10-70g/L, KOH: 10-40g/L at current density of not more than 1.8/dm2.