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A multilayer packaging technique in the food industry typically employs separate layers with unique mechanical and barrier properties to help preservation of food nutrition and flavors. Tie layers ...

The unique geometry of screw extruders allows handling very viscous media; thus, they can be used as continuous reactors to conduct polymerization reactions without using any solvents. This is call...

Though a Kaibel dividing-wall column (DWC) is able to save approximately 40% operation fees, the fear of controllability issues of the Kaibel DWC obstructs its large-scale industrialization. In our previous study, a composition/temperature cascade MPC-PI scheme was proposed with proportional–integral (PI) controllers stabilizing the operations and model predictive control (MPC) improving the performance. In the current paper, the MPC-PI scheme in combination with the data-driven soft sensor model replaces detecting compositions by detecting auxiliary variables, which is more applicable and practical. Although the same soft sensor model is applied, different Kalman filters used for error corrections will result in different composition estimation performances, which will consequently affect control performances for the Kaibel DWC. Soft sensors with different nonlinear Kalman filters have been studied and compared for the control scheme, containing the extended Kalman filter (EKF), unscented Kalman filter (UKF), and particle filter (PF). Research shows that the EKF can reach the setpoints of the product compositions faster than the UKF, but there are oscillations with reciprocating motion using the EKF. The speed of the PF to achieve stability is the fastest; however, the steady-state offsets remain. Therefore, the UKF is the most appropriate filter in composition soft sensors for the Kaibel DWCs, as its corresponding control performances are stable without the oscillations using the EKF and the steady-state offsets employing the PF.

A thermally regenerative ammonia-based battery (TRAB) is a new electrochemical energy device used for the recovery of low-grade waste heat. The use of a three-dimensional (3D)-printed Cu/C composit...

The separations of quaternary reversible reactions with the most unfavorable ranking of relative volatilities (i.e., the two reactants are the lightest and heaviest components and the two products ...

Wire mesh packing has been extensively utilized in laboratory and industry applications in rotating packed bed (RPB) because of the high mass transfer performance and low cost. Conventional wire me...

This work presented experimental and modeling studies on the simultaneous absorption of H2S and CO2 into the N-methyldiethanolamine (MDEA) and piperazine (PZ) solution in a rotating packed bed (RPB...

Liquid dispersion by impacting on wire mesh benefits many mass transfer processes. However, most of studies focused on the dispersion behaviors of liquid impacting on a one-layer wire mesh. In this...

Regeneration of spent caustic from liquefied petroleum gas sweetening in refineries is significant to save resources and reduce solid waste emissions. Conventional regeneration technologies have been widely used, but these technologies usually have a reactor and a separator in series which occupies a large space. In this work, simultaneous reaction and separation processes were proposed to be conducted in a rotating packed bed (RPB), aiming for the process intensification of spent caustic regeneration. Experimental results of laboratory tests show that the regeneration processes of mercaptide oxidation and disulfide separation were efficiently enhanced in the RPB. The side-line test, treating the actual spent caustic from a refinery, could achieve good performance for a long-time running. An artificial neural network model was applied for parameters analysis and prediction of the regeneration performance. This work demonstrated the feasibility of spent caustic regeneration in only one RPB unit, which disp...

Applying a HiGee reactor for H2S removal with solid sulfur generation by a chelated iron solution offers an economical way to exploit offshore natural gas. However, the high H2S removal efficiency ...

Absorption of carbon dioxide into sodium hydroxide solution has been extensively used for mass transfer investigation in gas–liquid contacting reactors. To obtain a reliable value of effective mass transfer area (A), the selection of fundamental parameters, such as reaction rate constant, diffusion coefficient, and solubility data, is significant for data processing, and very little literature has been reported on the selection of these parameters. Therefore, an evaluation of the sources of fundamental parameters needs to be given. In this work, six parameter sources, including classic literature and newly published papers, were evaluated for effective mass transfer area measurement in a rotating packed bed. Quantitative comparisons demonstrated that using different reaction kinetics models will cause a large deviation in the values of the effective mass transfer area. Further, the inconsistency between the sources of kinetics models and physical properties can also cause a large deviation, which should b...

This study employed a rotating packed bed (RPB) to enhance the absorption process of NOx and SO2 into Na2SO3 solution with the preoxidation by ozone. The absorption performance of NOx and SO2 was e...

The use of porous copper foam to increase the electrode surface area and power generation in thermally regenerative ammonia-based batteries (TRABs) is proposed and investigated. The incorporation of copper foam leads to a 38% increase in maximum power compared to that of typical copper plate. The electrode thickness not only influences the electrode surface area but also affects mass transfer, especially the ammonia transfer inside the anode. The optimal thickness of copper foam in terms of total charge, power, and power density is 10 mm. The power generation increases as the ammonia concentration is increased to 1 mol/L due to enhanced mass transfer, while further increase in the ammonia concentration (2 mol/L) leads to ammonia crossover and a decrease in power. Electricity generation is stable over 14 discharging batch cycles (>28 h), and the maximum power is maintained in the range of 58 ± 5 mW.

Although dividing wall technology is very effective for process intensification of distillation, the resultant dividing-wall distillation columns (DWDCs) exhibit strongly interactive and highly nonlinear behaviors, which may pose great challenges to process operations. Proportional–integral (PI) controllers can stabilize the operation of the DWDC, but their performances are frequently far from satisfactory. Model predictive control (MPC) can potentially improve performance sharply, but the stringent requirements on the qualities of the embedded model considerably lower its robustness. To suppress these two deficiencies, in this work a cascaded control structure by combining the MPC and PI controllers is proposed for the DWDC. The PI controllers regulate the stage temperature in the inner layer, serving to quickly stabilize the DWDC, while the MPC directly controls the product compositions in the outer layer, addressing the strongly interactive and highly nonlinear behaviors of the DWDC. Two typical cases,...

CO2 leakage is a fatal issue for the successful application of CO2 geological storage. In this paper, a method using CO2 triggered gelation is proposed to control the CO2 leakage during CO2 geological storage process. The mechanisms of CO2 triggered gelation was illustrated schematically. The effectiveness of this method for blocking CO2 leakage was evaluated by experimental works using sand-pack model. Reactive flow simulations were conducted to reproduce the experimental results and investigate field-scale feasibility of this method. The results show that this method can control the assumed leakage and the blocking performance was reproduced well by the lab-scale reactive flow simulation model. The results of simulation indicate that gel can be formed and absorbed more easily near the injection point. Feasibility of this method in field-scale were demonstrated with different scenarios of preplaced gel system. Infill drilling and monitoring method with high accuracy are recommended to assist this method.

Electrochemical oxidation is considered as a promising technology for wastewater treatment. In this work, a novel rotating multielectrodes reactor (RMER) has been developed to intensify the electro...

Water contamination by iodide has attracted much public attention in recent years due to its impact on public health. In this work, a novel sorbent Ag-D201 was synthesized by modifying a strong ani...

A novel rotating packed bed (RPB) reactor is first adopted to intensify the reaction of isobutane alkylation with 2-butene catalyzed by H2SO4. This work investigated reaction performance, and reaction conditions were optimized. Under the optimal conditions, the research octane number (RON) reached 98.85. Meanwhile, the yields of C8 and trimethylpentanes were 90.65% and 85.47%, respectively. The reaction efficiency was tremendously improved by using RPB due to its high efficiencies of mass transfer and micromixing. More importantly, the inner mole ratio of isobutane to 2-butene was dramatically decreased in RPB, which means the energy cost of material cycling in the alkylation process could be extremely reduced. Moreover, an empirical correlation model was proposed to predict the multiproduct yields and RON with a deviation within ±10%. In conclusion, RPB reactor is a highly promising industrial platform for the process of H2SO4 alkylation.

To ensure steady operation of gas transmission lines and meet the utilization specification of downstream processes, gas dehydration is employed in offshore natural gas production, where urgent demands for space and size exist. In this work, a rotating packed bed (RPB) was used to intensify the triethylene glycol (TEG) dehydration process and the effects of operating variables on the overall volumetric mass transfer coefficient (Kya) and height of mass transfer unit (HTU) were investigated. The value of HTU in a RPB was measured to be 4.3–7.9 mm, which was at least an order of magnitude lower than that in conventional columns, indicating the significant reduction in the size of the dehydration apparatus. The predicted Kya matches well with the experimental data, and the mean relative error (MRE) is only 6.68%.

This work presents a novel process of nano-Ni preparation by liquid reduction method without surfactant in a combined reactor of a rotating packed bed (RPB) and a stirred tank reactor (STR). The reaction mechanism of this process was studied, and the effects of different operating conditions including rotation speed, NaBH4 concentration, liquid volumetric flow rate, and liquid circulation time on the characteristics of the nano-Ni were systematically investigated in the RPB to control the morphology and average particle size of the prepared nano-Ni. The average particle size of the prepared nano-Ni can be adjusted from 42 to 130 nm by changing operating conditions, and the prepared nano-Ni with a face centered cubic (FCC) structure, an average particle size of 42 nm, and a particle size distribution of 30–60 nm was obtained under the optimal operating conditions. This research provides a novel pathway and theoretical basis for controllable preparation production of nano-Ni.

In our recent work, the arrangement of multiple reactive sections is found to greatly enhance the steady-state performance of reactive distillation columns disproportionating trichlorosilane to silane. In the current research, process dynamics and controllability are studied through in-depth comparative analysis of open-loop and closed-loop behaviors between three reactive distillation columns with, respectively, a single reactive section (RDC-SRS), double reactive sections (RDC-DRS), and triple reactive sections (RDC-TRS). In the regulation path, although the arrangement of double and triple reactive sections reduces slightly the process gains between the bottom product composition and reboiler heat duty in the RDC-DRS and RDC-TRS, it helps to alleviate the coupling between the bottom product composition and reflux flow rate, thereby gaining increases in process controllability as compared with the RDC-SRS. In the disturbance path, the arrangement of double and triple reactive sections results in no inte...

This work takes advantage of the unique thermally reversible dissociation/association feature of C–ON bonds in alkoxyamine (Diol) to facilitate the reprocessability of poly(butyl methanol methacrylate) (PBMM) rubber with excellent thermal and mechanical properties. Isocyanate groups were incorporated into the PBMM backbone and then reacted with hydroxyl groups in Diol to obtain cross-linked PBMM rubber. Although its cross-linking degree is slightly lower than the conventional cross-linked rubber by an irreversible cross-linker (Dieg), it shows a higher tensile strength and elongation at break. Its decomposition temperature is about 50 °C higher than PBMM cross-linked by Dieg. Furthermore, the dissociation of C–ON bond at high temperature can break the cross-linking network of PBMM rubber to form a flowable and reprocessable melt and show an excellent ability of reshaping and healing; the association of thermally reversible C–ON bond can completely recover the cross-linking network and mechanical propertie...

Glycyrrhetinic acid (GA) is the pentacyclic triterpenoid hydrophobic aglycone with many pharmacological effects and biological activities. Glycosylation is often used to improve the aglycone’s properties such as solubility, stability, and pharmacological potency. UDP-glycosyltransferases (UGTs) are the main enzymes to catalyze this conversion via transferring glycosyl moiety to corresponding acceptor substrates in nature. However, a glycosyltransferase which can transfer glucose to GA has not been reported yet. The glycosyltransferase UGT73C11 from the plant Barbarea vulgaris was reported with the glycosylation function to compounds which are similar to GA in chemical structure. In this study, UGT73C11 was selected to express functionally in Escherichia coli and purified as the biocatalyst for the glycosylation of GA. As a result, the recombinant UGT73C11 catalyzed UDP-glucose and GA to produce a new compound GA-3-O-monoglucose. The product GA-3-O-monoglucose was characterized by HPLC and LC–ESI-MS spectr...

As one of the important bone regeneration materials, α-calcium sulfate hemihydrate (α-CSH) has attracted widespread attention. In this study, a facile method was developed to prepare α-CSH with low aspect ratio via high-gravity continuously reactive precipitation of a calcium sulfate dihydrate (CSD) precursor, using ethanol as a morphology modifier in a rotating packed bed (RPB) reactor, combined with CaCl2 salt solution method under atmospheric pressure with the addition of citric acid with a low concentration (0.06 wt %). The precipitation time of CSD powders in the RPB was dramatically shortened from 30 min to 1 s, and the precursor exhibited more regular short rod shapes and much smaller size, compared to that obtained in a conventional stirring tank reactor (STR). Furthermore, calcium sulfate bone materials with high stability and good mechanical property were prepared by mixing α-CSH and normal saline with a liquid–solid ratio of 0.6. The RPB products had a higher compressive strength (2–3 times) th...

The conventional method for configuring double temperature difference control (DTDC) schemes relies on sensitivity analysis (SA) and singular value decomposition (SVD) analysis, respectively, to determine sensitive and reference stages. Since no considerations are given at all to the interactions between the synthesized double temperature differences (DTDs) and to the coordination between the upper and lower temperature differences (TDs) subtracted in each synthesized DTD, the conventional method may lead to DTDC schemes that fail to secure tight product quality control of distillation columns. In this article, a novel method is proposed that employs a newly defined metric in our recent work, the averaged absolute variation magnitudes (ASVM), to determine the two reference stages in each DTDC loop. The ASVM measures the variations of TDs between the sensitive stage and the remaining ones with the assumption of complete rejection of all disturbances concerned and can thus reflect the inherent characteristi...

Reactive distillation columns with double reactive sections (RDCs-DRS) at the top and bottom are especially favorable for the separations of reacting mixtures featuring the most unfavorable ranking of relative volatilities. In this article, their dynamics and control are studied in great detail, with special attention given to the influences of feed splitting on process dynamics and controllability. Because of the totally refluxed and totally reboiled operation mode plus an intermediate-product withdrawal, the RDC-DRS is generally characterized by severe under-dampness between the intermediate-product compositions and the reboiler heat duty (i.e., the regulation path) and by severe asymmetry between the intermediate-product compositions and the heaviest reactant feed flow rate (i.e., the disturbance path), consequently posing a great challenge to tight product quality control. With feed splitting of the lightest and heaviest reactants in the RDC-DRS (RDC-DRSFS), the simultaneous suppression of the under-d...

To better understand the startup process, the evolution of voltage output, energy gain and output, active biomass, and electrochemical performance of microbial fuel cells (MFCs) started up under different external resistances (10, 50, 250, and 1000 Ω) was investigated. In addition, the influences of external resistance and mass transfer on the anodic biofilm distribution of MFCs were also investigated. The results showed that MFCs with a decreased external resistance during startup had an increased evolution rate of energy gain, energy output, active biomass, and maximum power density but a reduced voltage evolution rate. A low external resistance for startup resulted in a thick and compact biofilm. As the flow field induced mass transfer, the biofilm was mainly distributed on the carbon cloth against the flow channel, and the biomass decreased along the flow direction. The compact biofilm on the surface resulted in a poor mass transfer and limited biofilm development inside the electrode.

With reference to the disproportionation of trichlorosilane to silane, a three-stage consecutive reversible reaction with rather unfavorable reaction kinetics of a near zero thermodynamic conversion, an in-depth comparison in steady-state performance is performed between the reactive distillation column with a single reactive section (RDC-SRS) and those with multiple reactive sections (RDC-MRS), under the assumptions of the same total number of stages and the same total amount of catalyst employed. With the incremental arrangement of reactive sections, the RDC-MRS shows a steady improvement in steady-state performance with considerably reduced operating cost and capital investment as compared with the RDC-SRS. The great advantages originate essentially from the additional degrees of freedom resulting from the arrangement of multiple reactive sections in process synthesis and design. Apart from the coordination effect to the three-stage consecutive reversible reactions processed, the additional degrees of ...

The deformation of the dispersed phase in polymer blends by tape extrusion was studied systematically under different processing conditions and viscosity ratios of the dispersed phase to the matrix. During tape extrusion, the spherical dispersed phases were first elongated into rotational ellipsoidal or rodlike shapes and then merged to form longer and even endless microfibrils by coalescence, which were eventually squeezed into highly oriented ribbons. The speed of two running rollers has a large effect on the morphology development of the dispersed phase. With an increase of the roller surface speed, the stretching and squeezing forces increased dramatically. As a result, the dispersed phase gradually deformed from spherical to ellipsoidal, fibrous, and ribbonlike shapes. More interestingly, the tensile strength of the obtained blend film with highly oriented ribbons increased significantly as well. The viscosity ratio of the dispersed phase to the matrix is another important factor influencing the form...

Bio-oil from the catalytic pyrolysis of algae biomass is an attractive energy source. To improve algae bio-oil properties for cofeeding applications in conventional oil refineries, bimetallic Ni–Cu...