The transfer rate between fluids in a microreactor is directly influenced by the mixing within the reactor, which subsequently impacts the reaction rate. This paper investigates the flow behavior and macro-mixing perf...The transfer rate between fluids in a microreactor is directly influenced by the mixing within the reactor, which subsequently impacts the reaction rate. This paper investigates the flow behavior and macro-mixing performance in a microreactor. First, the flow performance of the Ehrfeld Miprowa microreactor is studied. Cold experiments are conducted to examine fundamental flow laws and verify the accuracy of the chosen computational fluid dynamics simulation model.Subsequently, macro-mixing performance in the microreactor, both with and without internal components, is investigated through both experiment and simulation. A bromocresol violet–NaOH–H2SO4 system is utilized in the macro-mixing experiments, which explore the effects of flow rate and internal components on macro-mixing. The Navier–Stokes equation is adopted as the computational model for macro-mixing simulations, which also consider the mass transfer and diffusion of tracer. The simulation results are in good agreement with the experimental results. Both experimental and simulation results demonstrate that the presence of internal components in the microreactor enhance its macro-mixing performance.展开更多
A dynamic mass transfer model of isobutane/butene alkylation over solid acid catalysts in a fixed bed reactor was established. In the model, a modified equation for the relationship between point activity and effectiv...A dynamic mass transfer model of isobutane/butene alkylation over solid acid catalysts in a fixed bed reactor was established. In the model, a modified equation for the relationship between point activity and effective diffusion coefficient was proposed. It is found that the simulation results fit the experimental data well and the breakthrough time of the bed layer is predicted accurately. By modeling the alkylation process, the time-space distribution of butene and point activity profiles of catalysts can be obtained. Furthermore, the reasons for the deactivation of solid acid catalysts were investigated. It indicates that the main reason for the deactivation of catalysts is the site coverage near the inlet of the reactor, while it is ascribed to the steric effect in the region far away from the inlet.展开更多
A cross-flow microfiltration process had been developed to separate alumina fine particles from the suspension using a stainless steel membrane tube with a pore size of 10 μm. The influence of cross-flow velocity and...A cross-flow microfiltration process had been developed to separate alumina fine particles from the suspension using a stainless steel membrane tube with a pore size of 10 μm. The influence of cross-flow velocity and trans-membrane pressure on the permeate flux and the solid holdup in permeate had been investigated. It was found that both the permeate flux and the solid holdup in permeate decreased with time. Moreover, the permeate flux increased with an increasing transmembrane pressure but the influence of cross-flow velocity on the permeate flux was quite complex. Both the permeate flux and the solid holdup in permeate in long term filtration had been studied. The operation of cross-flow microfiltration could be carried out stably for 10 hours with the permeate flux values ranging from 520.5 to 936 L/(m^2·h) at rs=1%, while it could continue in 10 hours with the permeate flux values ranging from 226 to 432 L/(m^2·h) at rs=5%. The solid holdup in permeate had been less than 10 mg/L during the whole operating cycle.展开更多
Two kinds of gases were used to investigate the influence of gas density on the hydrodynamic characteristics in a bubble column. It can be found out that higher gas density leads to smaller bubble diameter and the flo...Two kinds of gases were used to investigate the influence of gas density on the hydrodynamic characteristics in a bubble column. It can be found out that higher gas density leads to smaller bubble diameter and the flow patterns are different for the both gases. Energy balance mechanisms are analyzed by considering the gas density difference. Models were developed to predict the average bubble diameter with good accuracy.展开更多
The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Bronsted acid and Lewis acid were analyzed using molecular simulation technology. Compared with th...The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Bronsted acid and Lewis acid were analyzed using molecular simulation technology. Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Bronsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.展开更多
基金supported by the National Natural Science Foundation of China (No. 5197050207)。
文摘The transfer rate between fluids in a microreactor is directly influenced by the mixing within the reactor, which subsequently impacts the reaction rate. This paper investigates the flow behavior and macro-mixing performance in a microreactor. First, the flow performance of the Ehrfeld Miprowa microreactor is studied. Cold experiments are conducted to examine fundamental flow laws and verify the accuracy of the chosen computational fluid dynamics simulation model.Subsequently, macro-mixing performance in the microreactor, both with and without internal components, is investigated through both experiment and simulation. A bromocresol violet–NaOH–H2SO4 system is utilized in the macro-mixing experiments, which explore the effects of flow rate and internal components on macro-mixing. The Navier–Stokes equation is adopted as the computational model for macro-mixing simulations, which also consider the mass transfer and diffusion of tracer. The simulation results are in good agreement with the experimental results. Both experimental and simulation results demonstrate that the presence of internal components in the microreactor enhance its macro-mixing performance.
文摘A dynamic mass transfer model of isobutane/butene alkylation over solid acid catalysts in a fixed bed reactor was established. In the model, a modified equation for the relationship between point activity and effective diffusion coefficient was proposed. It is found that the simulation results fit the experimental data well and the breakthrough time of the bed layer is predicted accurately. By modeling the alkylation process, the time-space distribution of butene and point activity profiles of catalysts can be obtained. Furthermore, the reasons for the deactivation of solid acid catalysts were investigated. It indicates that the main reason for the deactivation of catalysts is the site coverage near the inlet of the reactor, while it is ascribed to the steric effect in the region far away from the inlet.
文摘A cross-flow microfiltration process had been developed to separate alumina fine particles from the suspension using a stainless steel membrane tube with a pore size of 10 μm. The influence of cross-flow velocity and trans-membrane pressure on the permeate flux and the solid holdup in permeate had been investigated. It was found that both the permeate flux and the solid holdup in permeate decreased with time. Moreover, the permeate flux increased with an increasing transmembrane pressure but the influence of cross-flow velocity on the permeate flux was quite complex. Both the permeate flux and the solid holdup in permeate in long term filtration had been studied. The operation of cross-flow microfiltration could be carried out stably for 10 hours with the permeate flux values ranging from 520.5 to 936 L/(m^2·h) at rs=1%, while it could continue in 10 hours with the permeate flux values ranging from 226 to 432 L/(m^2·h) at rs=5%. The solid holdup in permeate had been less than 10 mg/L during the whole operating cycle.
基金financially supported by the National Key Basic Research Development Program "973" Project (2012CB224806) of China
文摘Two kinds of gases were used to investigate the influence of gas density on the hydrodynamic characteristics in a bubble column. It can be found out that higher gas density leads to smaller bubble diameter and the flow patterns are different for the both gases. Energy balance mechanisms are analyzed by considering the gas density difference. Models were developed to predict the average bubble diameter with good accuracy.
基金the National Key Basic Re-search and Development Program (No. 2006CB202505).
文摘The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Bronsted acid and Lewis acid were analyzed using molecular simulation technology. Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Bronsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.
