Condensation Of Methanol Research Articles

The influence of multi-step modification method on the adsorption effect of alkali metal adsorbent in high temperature corrosive environment

In order to mitigate the serious high-temperature corrosion problem caused by gaseous alkali metal salts on the heating surface of boilers, the adsorption effect of kaolinite for alkali metal vapor stood out among many silicon-aluminum-based adsorbents. To improve the adsorption capacity of kaolinite for alkali metal vapor, a novel multi-step modification method was proposed in this reported work. The multi-step modification method consisted of the following four steps, which were pre-intercalation, replacement intercalation, multiple intercalation, and exfoliation, and it was found that the multi-step modification method resulted in the increase of the particle size, the expansion of the interlayer spacing, and the expansion of the porosity structure of kaolinite. The physicochemical analyses showed that the multi-step modification method made it easier to dehydrate kaolinite to produce metakaolinite. In addition, it was found that the multi-step modification method led to the generation of a new crystalline phase of kaolinite, which was formed by the dehydration and condensation of methanol and AlOH groups. It also led to the pre-removal of some of the hydroxyl groups in kaolinite. The insoluble sodium loading capacity of the multi-step modified kaolinite was enhanced by 64.47% and the insoluble potassium loading capacity was enhanced by 29.68% under the adsorption condition of 850 °C for 45 min. Therefore, the multi-step modification method enhanced the alkali metal vapor adsorption capacity of raw kaolinite under high-temperature environment, which laid a certain foundation for subsequent research in this field.

Synthesis of a Series of Methyl Benzoates through Esterification with a Zr/Ti Solid Acid Catalyst

Methyl benzoate (MB) compounds are prepared by reacting various benzoic acids with methanol using an acidic catalyst. In this study, the solid acids of zirconium metal solids fixed with various substances were studied. We determined that zirconium metal catalysts with fixed Ti had the best activity. The catalytic synthesis of a series of MB compounds using titanium zirconium solid acids was studied. The direct condensation of benzoic acid and methanol using a metallic Lewis acid without other auxiliary Bronsted acids is reported for the first time.

Thermo-hydraulic rating of a shell and tube heat exchanger for methanol condensation

Shell and tube heat exchangers are the most common type of heat exchangers, and are applicable for a wide range of operating temperatures and pressures. In the present work the thermo-hydraulic rating of a shell and tube heat exchanger was carried out, in order to perform the condensation of a methanol stream using water as coolant. The overall heat transfer coefficient for both the sensible-heat and latent-heat zone had values of 166.41 W/m2.K and 1,198.39 W/m2.K, respectively; while the required total heat transfer area and percent excess area had values of 38.08 m2 and 3.05 %, respectively. The pressure drops of methanol and water streams reached the values of 51,490.84 Pa and 2,890.50 Pa, respectively. The proposed shell and tube heat exchanger can be employed satisfactorily for the demanded heat transfer service, since the calculated percent excess area does not exceed 25%, and the pressure drop of the water stream does not exceed the value of 80,000 Pa.

Methanol sono-pyrolysis for hydrogen recovery: Effect of methanol concentration under an argon atmosphere

A number of theoretical and experimental works showed the possibility of increasing the sonochemical production of hydrogen through the pyrolysis of methanol within the acoustic cavitation (i.e. sonolysis of aqueous methanol solution). In this study, numerical simulations have been conducted in order to reveal, for the first time, the effect of methanol concentration (in the bulk liquid) on the maximal sonochemical efficiency for hydrogen yielding, methanol conversion and the broadness of active bubbles range. The current adopted model is built on a set of ordinary differential equations that account for non-equilibrium evaporation and condensation of water vapor and methanol at the bubble wall, thermal conduction both within and outside the bubble and heat of chemical reactions. All numerical simulations were carried out for a single bubble oscillating in O2 and/or argon-saturated water with varying concentration of methanol. It was found that the variation of methanol concentration (0–100% (v/v)) affects slightly the broadness of active bubbles ranges for methanol consumption. Conversely, for hydrogen production, a gradual decrease of the active bubbles ranges is observed for methanol concentration greater than 20%. The maximal sonochemical efficiency for hydrogen yielding, methanol conversion and the broadness of active bubbles ranges (for H2 production and CH3OH conversion) is obtained at 80% of argon and for methanol concentration between 7% and 20%. The yield of hydrogen increased by 26.16 and 22.4 times at 10 and 20% (v/v) of methanol in bulk solution, respectively, whereas CH3OH conversion decreased by 13.84 and 22.3%, respectively.

Development of novel solvent swap methodologies using CFD

The methodologies developed in this paper were of the continuous plate solvent exchanger and the rising bubble solvent swap. The plate solvent exchanger was highly modular and scalable. The effect of the gas overhead composition, gas flowrate and gas temperature were investigated for the system. Optimisation of the plate solvent exchanger involved the use of a pure air gas overhead and minimising the liquid flowrate and gas temperature while maximising the gas flowrate. The rising bubble solvent exchanger operated at lower flowrates and was more economical with gas and solvent. The counter-current operation of the device ensured each bubble underwent complete evaporation of dcm and complete condensation of methanol. A decreased bubble rise velocity, an increased bubble addition rate and decreased number of bubbles yielded the minimum column height for the rising bubble solvent swap. The rising bubble solvent swap successfully overcame the mass transfer inefficiencies associated with Raoult’s Law.

Study on the application of sulfonation catalysis in a new formaldehyde recovery process

This study proposed a new catalytic conversion process using a sulfonated catalyst to promote the condensation reaction of methanol and formaldehyde (FA) to form methylal (DMM). This method can remove FA while generating the valuable chemical product DMM. A series of SiO 2 -xSO 3 H catalysts were developed, and the synergistic effect of the sulfonic acid group vacancy and hydroxyl vacancy contents was evaluated by adjusting the activation temperature and sulfonation ratio. When the activation temperature was 60 °C, the FA yield reached 82.3%, and DMM selectivity was 80.4%. The FA recovery rate was much higher than in other studies. A series of characterization studies revealed that when there were few -SO 3 H groups, the hydroxyl content increased, providing more activation centers for forming the formic acid by-product from FA. The dehydration and condensation of formic acid and methanol formed methyl formate (MF). However, when there were too many -SO 3 H groups, side reactions of methanol and FA occurred preferentially. Therefore, the synergistic effect of the -SO 3 H group and hydroxyl group content was the fundamental reason for the exceptional catalytic performance. Furthermore, in-situ infrared spectroscopy revealed the possible reaction mechanism of methanol and FA on sulfonated silica gel and verified the conclusion drawn from the catalyst characterization. This approach overcomes the disadvantages of the high cost of FA absorption and difficulty of industrialization due to the high reaction temperature and provides the potential to “turn waste into treasure” during FA recovery while providing new avenues to solving the problem of FA pollution.

Study on the optimized Al2O3–SO3H catalysis for a new formaldehyde recovery process

Formaldehyde is a dangerous chemical present in many industrial waste gases. It can be recovered via catalytic processes; however, many of these require costly precious metals operating under limited reaction temperatures, making their industrialization difficult. This paper proposes a novel method of formaldehyde recovery. A sulfonation catalyst is used to promote a condensation reaction of methanol and formaldehyde to form methylal. Hence, a valuable chemical product is obtained while removing formaldehyde. A series of Al2O3-xSO3H catalysts were designed and the effects of surface acidity and hydroxyl groups on catalytic activity were explored by varying the activation temperature and sulfonation ratio. At an activation temperature of 60 °C, the yield of formaldehyde reaches 78.62% and the selectivity to methylal reaches 80.11%. This recovery rate is much higher than those reported in other studies. Through a series of characterizations, it was found that when the content of –SO3H groups is low, the hydroxyl content increases, which provides more activation centers for the formation of by-product formic acid from formaldehyde, and for the dehydration and condensation of formic acid and methanol to form methyl formate. At the same time, when the content of –SO3H groups is too high, side reactions of methanol and formaldehyde occur preferentially. Therefore, the synergistic effect of the contents of –SO3H and hydroxyl groups is the fundamental cause of the excellent catalytic performance. Based on in-situ infrared research, a possible mechanism of the reaction between methanol and formaldehyde on sulfonated silica gel is proposed, which also verifies the characterization of the catalyst. This research presents new possibilities for solving the problem of formaldehyde pollution.

New Pyrazole-Based Ligands: Synthesis, Characterization, and Catalytic Activity of Their Copper Complexes

The purpose of this study is to demonstrate the synthesis of pyrazole-based ligands and to evaluate their catalytic properties in the oxidation reaction of catechol to o-quinone. The ligands were prepared via the condensation of (3,5-dimethyl-1H pyrazol-1-yl)methanol A with the appropriate primary amine. Four pyrazole-based ligands were successfully synthesized and characterized. These ligands provide one pyrazole sp2-nitrogen, one pyridine sp2-nitrogen, and one amine sp3-nitrogen, which were capable of coordinating to the metal. For evaluating the catalytic activity, the experiments were tested by varying the type of solvent, metal ion, anion in the metal salt, and ratios of ligands and metal salts. Excellent catalytic activities for the oxidation of catechol to o-quinone were obtained. The copper (II)-based complexes showed better reactions rates than those based on other metals (e.g., nickel, tin, and barium), which was due to the fact that the active catalytic site of the catecholase enzyme has two active sites from the existence of copper (II) ions. The composition ratios of ligands and metal salts as well as the type of anion in the metal salt bring impacts to the formation of complexes. We found also that the type of solvent contributes to the interaction and dilution of reactants in the solvent. This study demonstrated that the present ligands can be used as a model for further developments in catalytic processes relating to catecholase activity.

Failure analysis for tube bundle of methanol condensation recovery heat exchanger

The S30408 tube bundle of methanol condensation recovery heat exchanger in a chemical company was found leaked during use. The cause of tube bundle leakage was analyzed by means of macroscopic inspection, chemical composition analysis, metallographic analysis, hardness test and leakage fracture analysis. The results show that formic acid and chloride condensate are formed by the exhaust gas in the shell side near the outlet of the shell side, which results in the spot corrosion and stress corrosion cracking of the tubes. Surface coating or replaced material is recommended to prevent such failure.

Simultaneous methanol production and separation in the methanol synthesis reactor to increase methanol production

In this study, the condensation of methanol and water in unoccupied layers near the coolant tubes of the gas-cooled reactor in mega-methanol plants are investigated. In the Lurgi mega-methanol plants, named conventional configuration (CC), water-cooled reactors are in series with the gas-cooled reactor. These reactors are composed of only two sections, shell and tubes. In the novel configuration (NC), the gas-cooled reactor is modified and consists of three sections including shell, tubes, and mesh. A perforated plate, named mesh, is surrounding each tube by 5 mm from the outer wall of the tube. In the aforementioned space, which has no catalyst, condensation occurs. The coolant temperature in the inlet of the tube of gas-cooled reactor in NC is 20 K smaller than that of CC. The temperature reduction leads to more gas condensation and as a result, the methanol production of NC increases by 20 % compared with CC. A one-dimensional modeling is applied to compare the performances of NC and CC. The results of CC are validated with industrial data.

Analysis on Geometry of Fluid Flow Manifold in Direct Methanol Fuel Cell

Fuel cells are the devices that convert chemical energy into electrical energy through an electrochemical reaction. Direct Methanol Fuel cell (DMFC) is a proton exchange membrane fuel cells in which methanol is used as fuel. Its high energy density makes it suitable for fuel cells. Even though carbon dioxide is produced, there is no production of sulfur or nitrogen oxides. The problems usually occurred while working with DMFC are methanol crossover, condensation of methanol, water management and carbon dioxide release. In that the uneven flow distribution, accumulation of carbon dioxide bubbles in the fuel cell are the major issues in DMFC. To prevent these issues, this work focuses on the theoretical and experimental studies on development of fuel cells with special importance to geometry of the manifold. This paper provides the optimal solution for preventing uneven flow distribution that is the usage of squoval shaped manifold which is the combination of both square and circle. Performance of DMFC with squoval shape manifold is evaluated experimentally and is compared with square shape manifold and rectangle shape manifold geometry design.

Analysis on Geometry of Fluid Flow Manifold in Direct Methanol Fuel Cell

Fuel cells are the devices that convert chemical energy into electrical energy through an electrochemical reaction. Direct Methanol Fuel cell (DMFC) is a proton exchange membrane fuel cells in which methanol is used as fuel. Its high energy density makes it suitable for fuel cells. Even though carbon dioxide is produced, there is no production of sulfur or nitrogen oxides. The problems usually occurred while working with DMFC are methanol crossover, condensation of methanol, water management and carbon dioxide release. In that the uneven flow distribution, accumulation of carbon dioxide bubbles in the fuel cell are the major issues in DMFC. To prevent these issues, this work focuses on the theoretical and experimental studies on development of fuel cells with special importance to geometry of the manifold. This paper provides the optimal solution for preventing uneven flow distribution that is the usage of squoval shaped manifold which is the combination of both square and circle. Performance of DMFC with squoval shape manifold is evaluated experimentally and is compared with square shape manifold and rectangle shape manifold geometry design.

Dynamics and Kinetics of Methanol-Graphite Interactions at Low Surface Coverage.

The processes of molecular clustering, condensation, nucleation, and growth of bulk materials on surfaces, represent a spectrum of vapor-surface interactions that are important to a range of physical phenomena. Here, we describe studies of the initial stages of methanol condensation on graphite, which is a simple model system where gas-surface interactions can be described in detail using combined experimental and theoretical methods. Experimental molecular beam methods and computational molecular dynamics simulations are used to investigate collision dynamics and surface accommodation of methanol molecules and clusters at temperatures from 160 K to 240 K. Both single molecules and methanol clusters efficiently trap on graphite, and even in rarified systems methanol-methanol interactions quickly become important. A kinetic model is developed to simulate the observed behavior, including the residence time of trapped molecules and the quantified Arrhenius kinetics. Trapped molecules are concluded to rapidly diffuse on the surface to find and/or form clusters already at surface coverages below 10-6 monolayers. Conversely, clusters that undergo surface collisions fragment and subsequently lose more loosely bound molecules. Thus, the surface mediates molecular collisions in a manner that minimizes the importance of initial cluster size, but highlights a strong sensitivity to surface diffusion and intermolecular interactions between the hydrogen bonded molecules.

Green production of biodiesel over waste borosilicate glass derived catalyst and the process up-gradation in pilot scale

An efficient solid base catalyst derived from waste borosilicate glass, by its reaction with sodium hydroxide, is used here for the production of biodiesel from used cooking oil. The active phase of the catalyst is found to be Na2SiO3 and the material is highly effective in the production of fuel grade biodiesel till 4 numbers of repeated cycles. The catalyst is found to be tolerant to free fatty acid and water content in the oil feedstock. The procedure is up-graded in pilot scale with the aid of a set up made of polypropylene vessels where the formation of high pressure is avoided in the reactors by the continuous condensation of methanol, making the process a safer one. We report the use of a solid catalyst derived from waste materials in a pilot-scale biodiesel production unit for the first time, which has the potential to have an easy and cost-effective industrial scale up. The performance of the prepared biodiesel and its blends with petrodiesel in diesel engine is investigated and it is found that the biodiesel blend (B10) showed the best performance at all engine loads.

ZSM-5 surface modification by plasma for catalytic activity improvement in the gas phase methanol-to-dimethylether reaction

Abstract Dimethylether (DME) is nowadays considered as one of the most promising alternative fuels for the future. It has a very low climate impact, and can be produced in a renewable way, namely from the gas phase condensation of methanol over common acid catalysts such as γ-Al2O3 or zeolites. The challenge today is to switch from high reaction temperatures (300–350 °C) to lower ones (ideally 100–150 °C) in order to operate more energy-efficiently and with 100% selectivity to DMEThe methanol conversion needs to be increased below 300 °C in order to get high yields of DME even in that low temperature range. In the present paper, we show a way to achieve this in the case of the widely studied ZSM-5 zeolite. We show that submitting the zeolite to a cold plasma treatment before using it as a catalyst allows significantly increasing the yield of DME up to 300 °C. Indeed, the plasma treatment leads to a partial dealumination of the zeolite and thereby to an increase of the number of strong Bronsted acid sites which play a key role in the methanol-to-DME reaction mechanism.

Acrylic acid synthesis by oxidative condensation of methanol and acetic acid on B–P–V–W–Ox/SiO2 catalyst

The process of oxidative condensation of methanol with acetic acid to acrylic acid on B–P–V–W–Ox/SiO 2 catalyst modified by hydrothermal method has been studied. Modification of the catalyst by hydrothermal treatment of the carrier changes its physical and chemical properties, and therefore its catalytic properties. The influence of the main technological parameters – temperature, contact time and ratio of reagents on the selectivity and yield of the reaction products and on the conversion of acetic acid has been studied when hydrothermally treated catalyst was used. The best time of contact was 8 sec. which allows to reach the highest selectivity and yield of acrylic acid and methyl acrylate. The highest catalytic activity of the designed catalyst is observed at the reaction temperature of 673 K, however, it is impossible to increase temperature over this value due to the limited thermal stability of the catalyst and the sharp increase in the formation of complete oxidation products. With an increase of methanol part in the ratio of reagents (methanol: acetic acid) to 1,2:1, the selectivity of acrylic acid and methyl acrylate increases, and the selectivity of by-products is significantly reduced. The highest yield of the target products in the reaction of oxidative condensation of methanol with acetic acid is observed at a ratio of oxygen: acetic acid 1,5:1. The growth of the oxygen: acetic acid ratio promotes reduce of acetone and methyl acetate selectivity but does not change the selectivity of methyl acrylate and significantly increases the selectivity and yield of acrylic acid. At the best conditions of the reaction it was possible to achieve 54.7 % total yield of acrylic acid and methyl acrylate. Due to the wide availability and relatively low cost of the initial reagents (methanol and acetic acid), the synthesis of acrylic acid by the oxidative condensation of methanol with acetic acid in the presence of the developed catalyst is very promising

Dimethoxymethane as a Cleaner Synthetic Fuel: Synthetic Methods, Catalysts, and Reaction Mechanism

The increasing concerns regarding exhaust and CO2 emissions from fossil-based transportation fuels have propelled intensive research aimed at finding alternative fuel candidates to realize a clean and renewable fuel system. In this context, dimethoxymethane and its derivatives oxymethylene ethers, a class of oxygenated synthetic fuel, have recently attracted increasing interest because of their fascinating characteristics as a diesel blend compound to significantly reduce soot and nitrogen oxide formation. At present, dimethoxymethane production primarily relies on an established two-step process comprising methanol oxidation and methanol condensation with formaldehyde. Several new synthetic routes based on methanol or CO2/H2 have been proposed by adopting a reaction coupling strategy, which enables the production of dimethoxymethane in one step. A large variety of bi- and multifunctional catalysts have been developed for each synthetic route. This Review comprehensively summarizes the latest advances in ...

Виробництво акрилової кислоти: порівняння промислового та нових перспективних методів її одержання

Виконано порівняльний огляд основних перспективних методів одержання акрилової кислоти. Показано, що значного розвитку з огляду на доступність сировинної бази набув метод одержання акрилової кислоти з гліцерину (побічного продукту виробництва біодизелю), а також способом ферментації біомаси. Окрім цього, показано, що вдосконалення каталізаторів альдольної конденсації оцтової кислоти з формальдегідом в акрилову кислоту робить цей метод її синтезу одним із найбільш конкурентних. Встановлено, що модифікація поруватої структури B–P–W–V–Oх/SiO2 каталізаторів процесу альдольної конденсації є дієвим способом впливу на їхні каталітичні властивості. Оптимальним розміром пор B–P–W–V–Oх/SiO2 каталізаторів є 11–16 нм. В оптимальних умовах (температура 380 °С, час контакту 8 с) вихід акрилової кислоти в процесі альдольної конденсації оцтової кислоти з формальдегідом становить 68 % за селективності її утворення 91 %. Розроблений каталізатор також є ефективним у процесі окиснювальної конденсації метанолу з оцтовою кислотою. Особливістю цього методу є те, що в процесі утворюються одночасно два цінні продукти – акрилова кислота та метилакрилат. Сумарний вихід акрилатів становить 54,7 % за селективності їх утворення 80,1 % (температура 400 °С, час контакту 8 с). Розглянуто перспективи використання новітніх Se-вмісних каталітичних систем на мікрогелевій основі для низькотемпературного синтезу акрилової кислоти та метилакрилату з акролеїну.

Effect of oxygen donor alcohol on nonaqueous precipitation synthesis of alumina powders

Monodispersed alumina powders were prepared via nonaqueous precipitation process using aluminum powders as aluminum source, acetic acid as precipitant. Effect of oxygen donor and solvent alcohol such as methanol, ethanol, isopropanol on the preparation of ultrafine alumina powders and the precursor reaction mechanism have been investigated by XRD, FT-IR, TEM, FE-SEM and performance tests of sintered bodies. The intermolecular condensation of methanol with the catalysis of Lewis acid aluminum methoxide leads to hydrolysis of aluminum methoxide, forming amorphous precipitates, dehydration polycondensation of aluminum hydroxide and resulting in serious agglomeration of precipitates and alumina powders, the worst morphology and properties of sintered body. The pulling electron effect and steric hindrance of isopropyl group make the structure of aluminum isopropoxide overwhelmingly stable and relatively arduous to be replaced by precipitant acetic acid, which results in underdeveloped crystallinity and agglomeration of both precipitates and alumina powders, poor morphology and properties of sintered body. The optimized oxygen donor and solvent alcohol is ethanol. Monodispersed, high crystallinity C4H7AlO7 precipitates and alumina powders can be obtained when ethanol is used as oxygen donor and solvent, and the highest relative density, mechanical properties and the most homogeneous microstructure was obtained. The density, flexural strength, volume resistivity, breakdown voltage and thermal expansion coefficient are 99.1% of TD, 128.0 ± 2.2 MPa, 9.8 × 1016 Ω∙cm, 45.2 kV/mm and 7.6 × 10−6 °C−1, respectively. Precursor reaction mechanism is deduced that aluminum powders react with oxygen donor alcohol to form aluminum alkoxide with the catalyst iodine, and then react with acetic acid to form crystal C4H7AlO7 precipitates. Nonaqueous precipitation method is expected to become a promising candidate for mass production of alumina powders.

Influence of hydrothermal treatment of catalysts on their effectiveness in the process of acrylic acid and methyl acrylate synthesis via oxidative condensation of methanol with acetic acid

The purpose of the work was to investigate the effect of modification of the catalyst of oxidative condensation of methanol with acetic acid on acrylic acid and methyl acrylate selectivity and yield. It was carried out hydrothermal treatment of the support - silica gel, in the temperature range of 100-250 oC in the range of 25 oC. It was investigated the effectiveness of the developed catalyst in the optimal conditions: temperature – 400 oC, reagents ratio CH3OH: CH3COOH = 1.2: 1, oxygen concentration in the oxidant stream is 90 % and contact time – 8 seconds. Physical and chemical properties of the catalysts for the process of acrylic acid and methyl acrylate synthesis by oxidative condensation of methanol with acetic acid were determined. Hydrothermal treatment of the silica gel, KSKG brand was performed and based on this treated silica gel catalytic system SiO2 / B2O3-P2O5-WO3-V2O5 with the atomic ratio of components В:Р:W:V=3:1:0,18:0,12 were prepared. The catalysts were tested in the process of acrylic acid and methyl acrylate synthesis. It has been established that the best catalyst for the process of acrylic acid and methyl acrylate synthesis is the catalyst with a HTT temperature of 150 0С (under optimum conditions the temperature of the process is 400 ºС and contact time 8 s). At this temperature, it was possible to obtain acrylic acid and methyl acrylate with 54.7 % yield, total selectivity of acrylic acid and methyl acrylate – 97.6 %, acetic acid conversion – 56.9 %. It was established that increasing of hydrothermal treatment temperature leads to increasing of pore size of the catalysts and decreasing the acrylic acid selectivity and increasing of esters (methyl acetate and methyl acrylate) selectivity