Chemical Engineering and Processing - Process Intensification最新文献

To address the clogging of demister by elemental sulfur of high-sulfur gas fields, a rotary thread demister was proposed as an alternate. The results show: The feasibility of the rotary thread demister is verified through force analysis and simulation experiments; The experimental results revealed the Realizable k-ε turbulence model has the smallest average error of 3 %; Increases in rotational speed, count, diameter, and layers of the rotary thread enhance separation efficiency and pressure drop; Higher inlet velocities reduce separation efficiency while increasing pressure drop; Based on the response surface methodology and NSGA-II algorithm, the optimal parameters are determined, achieving separation efficiency of 100 % and pressure drop of 45.67 Pa for 19 μm sulfur particles and 20 μm droplets; The same parameters can remove the 3 μm size droplets and sulphur particles with separation efficiencies of 90.2 % and 92.3 %, respectively, at a pressure drop of 43.8 Pa without considering particle collisions.

Modification of grains using green technologies receiving more attention in today's world for better utilization. Browntop millet was treated at a frequency of 20 kHz using probe ultrasound at 100 & 200 W for 5–35 min of 5 min intervals between the treatment at the ratio of 1:5 (w/v). The impact of treatment on grains was evaluated utilizing several parameters, such as relative crystallinity (RC) of the treated samples, which decreased from 59.78 % to 34.41 % at 100 W and 22.84 % at 200 W. Change in the surface morphology of the samples was observed by SEM which had a positive impact on water absorption as it increased from 164% to 179.2%; thus, the cooking time in treated samples is reduced from 18.8 to 7.9 min. Thermal and pasting properties showed a decrease in temperature and increase in viscosity of the treated samples from 74 to 70.7 °C, and 4.23 Pa.s to 11.50 Pa.s this shows that grains with lesser gelatinized temperature tends to cook fast and has the softer texture, thus sonicated samples have better eating quality. Among all the trials 200 W 20 min were the optimal conditions for the browntop millet with lesser cooking time, relative crystallinity.

To address the issues of low adsorption efficiency of activated carbon in dyeing wastewater treatment, a dynamic adsorption process using activated carbon for wastewater treatment was proposed. A hydrocyclone was used as the carrier, and the adsorbent separation process was integrated into the same single device. Methylene blue (MB) was used to simulate printing and dyeing wastewater. The effects of initial concentration of MB solution, ratio of activated carbon quality to wastewater flow, and adsorption temperature on the adsorption efficiency were investigated. The results showed that the optimal adsorption efficiency of MB by activated carbon was 95.2 % when the initial concentration of MB solution was 12 mg/L, the ratio of activated carbon quality to wastewater flow was 0.5 mg/mL, and the adsorption temperature of MB solution was 44.5 °C. In addition, compared with the water bath oscillation method, the removal efficiency of MB was increased by 731 % under the same adsorption conditions. The research shows that it is feasible to treat printing and dyeing wastewater by using a hydrocyclone to enhance activated carbon adsorption. The research aims to provide a practical basis for future optimization of the structure and operation parameters of hydrocyclone and to reveal their wide application prospects.

The novel embedded flue-gas internal recirculation (FIR) combustion technology has garnered increasing attention in gas burners due to its notable advantages in combustion efficiency and ultra-low NOx emissions. In this study, we design FIR channels for a gas burner and investigate the impact of recirculation ratio (R) on temperature, combustion efficiency, concentrations of free radicals (H, O, CH), and NO concentration via Computational Fluid Dynamics (CFD) method. In addition, this paper explores and elucidates the dynamics of four NO production pathways, namely, thermal NO, prompt NO, N₂O, and NNH, as well as the contributions of the four pathways to total NO. Observations indicate a constrained range of FIR recirculation ratios, specifically between 23.2 % and 35 %. The combustion efficiency of the FIR burner is 96 % and 99.8 % at R = 23.8 % and R = 35.0 %, which is superior to conventional burners. Moreover, as R increases, both pathways for NO generation from N₂O and NNH are intensified as R exceeds 23.8 %. In the embedded FIR combustion system, the contribution of N₂O to total NO increases from 0.23 % to 0.78 %, while the percentage of prompt NO decreases to 0.19 %. These findings provide a development direction and technical guidance for the practical implementation of the embedded FIR technology.

This study introduces a compact Lab-on-Printed Circuit Board (PCB) device featuring thermal integrated microfluidic channels designed for nanoparticle synthesis. Commonly, complex heating chambers are employed to expedite reactions and enhance nanomaterial productivity, yet they pose challenges in temperature control and mixing rates within the reaction chamber. To address these issues, we propose a compact device composed of PDMS microfluidic channels and a PCB platform. The PCB heater, constructed to precisely regulate temperature within the microfluidic channels, utilizes copper lines as heating resistors, while an Arduino kit is employed for temperature measurement and control. Leveraging a Proportional–integral–derivative (PID) controller through programming, the device achieves rapid temperature increase and stable control within the microfluidic channels. Experimental validation demonstrates the operational principles and capabilities of this device, showcasing observable changes in nanoparticle size and morphology. Discussions on these observed results are included in this work.

Process intensification (PI) concepts have potential applications beyond the classic industrial problems solved by chemical engineering. This paper discusses the flow and mass transfer intensification using acoustic waves to enhance drug delivery to the nasal cavity. The efficiency of drug delivery to the nose still needs improvement, and the mechanisms related to using acoustic waves to increase it have yet to be studied. The influence of pressure pulsations induced by an acoustic wave (∼100 Hz) on the concentration, droplet size, and flow structure of the mists delivered from medical nebulizers was studied. The direct visualization showed that pulsations intensify aerosol deposition inside narrow channels due to particle displacement perpendicularly to the main flow direction. This motion also allows for particle penetration via narrow openings. UV-assisted observation of the intensified aerosol deposition inside the anatomical cast of the nasal cavity confirmed the importance of acoustic pulsations for intranasal drug delivery, also helping aerosol penetrate hard-to-reach areas (including the paranasal sinuses). A new idea regarding appropriate time control of acoustic pulsations has been proposed to improve the aerosol drug mass transfer in the nose. The study shows that PI has great potential to expand into new and interdisciplinary areas.

For millennia, plants have been a source of natural medicines used by humankind. In vitro cultures of plant organs, e.g., transgenic roots, provide a suitable environment for maintaining plant biomass and continuously producing plant-derived bioproducts. The in vitro cultures of plant biomass can be efficiently scaled up using disposable bioreactors with wave-type agitation conditions. The study aimed to investigate the influence of wave-type agitation conditions supported by the WAVE 25 bioreactor on biomass proliferation and secondary metabolite production offered by the in vitro system of Rindera graeca transgenic root culture. Two morphologically different pellets of R. graeca biomass have been observed: highly ramified for cultures performed at Re_L < 4000 and compacted for cultures performed at Re_L > 5200. The growth of transgenic root biomass cultured in the WAVE 25 bioreactor at Re_L = 1325 was over two times higher than for cultures performed in small-scale systems of oscillatory shaken Erlenmeyer flasks.

The toluene/methylcyclohexane cycle is a safe and practical Liquid Organic Hydrogen Carrier (LOHC) for the storage of hydrogen. Nevertheless, the dehydrogenation reaction of methylcyclohexane (MCH) should be improved to assure a total selectivity to toluene (TOL), avoiding the subproducts formation. In this research, a millireactor with channel internal diameter in the range of milimeters has been tested and evaluated in the dehydrogenation of MCH to TOL. The millireactor configuration confers it some features and advantages compared to fixed-bed reactors, e.g., better mass and energy transfer and increased performance (10–20 %). To verify these advantages, a comparison between conventional fixed bed (9 mm i.d.) and millireactor is carried out. Thanks to its configuration, the millireactor could control effectively the heat generated by the reactions to avoid hot-spot formation and the sintering of the catalyst. The results obtained demonstrate that the catalysts activity in the reaction is improved with the application of the millireactor respect the fixed-bed ones and neither catalyst sintering, nor pressure drop was appreciated during the catalytic tests. At the best reaction conditions, Tecnalia´s millireactor converses continuously up to 99 % of MCH to TOL with 100 % selectivity at atmospheric pressure, showing the huge potential of the millireactor concept.

A composite fluidized bed (SCFB), which integrated the bubbling fluidization and circulating fluidization into one bed, was developed in this work. Wavelet transform was employed to analyze time-series signals of the pressure fluctuations and the steady-state tracer injection technique was used to study the gas diffusion coefficient in SCFB. The energy contribution in BFB and CFB mainly concentrated on the macrostructures, while that in SCFB was caused principally by the mesostructures as gas velocity was high. The circulating particles could effectively reduce particle aggregates and promoted a uniform distribution of heavy particles in the bottom region. Radial dispersion coefficients in SCFB were greater than that in BFB and CFB, demonstrating that the circulating particles enhanced gas mixing in SCFB. The ratio of D_a/D_r in SCFB was less than that in BFB, indicating that gas-solid flow in SCFB was more closely to the mixed-type flow compared to the BFB.

Waste heat recovery (WHR) in steel shops and valorization (WHV) to electricity and steam can considerably cut off the environmental burden of the steelmaking process. However, WHR/WHV is a complex issue, as there are multiple, interrelated, parameters that needs quantifying at recovery and transfer levels. In this context, we developed and launched an optimization tool that is based on mixed-integer linear programming, commercially called Heat2Power®, to provide customized WHR/WHV solutions that strictly respect all the user's objectives. For instance, the user can define the waste heat streams availability over the examined time period, the waste heat valorization path (electricity or steam production or both) and selection of the thermodynamic cycle or turbine technology to be used (inputs). The Heat2Powe® tool can be used either as a customized process calculator calculating the economics and the volumetric footprint of the WHR/WHV unit (output 1), should the user define all the system parameters or as a process optimizer, should the user not be able to specify all the design parameters, leaving the optimizer to select the most efficient WHR/WHV technology for a given operating window (output 2). Comparing the Heat2Power® results with data retrieved from a real WHR/WHV case of the steel industry, it is found that a difference of less than 20 % is attained when identical operating conditions are considered, rendering Heat2Power® a trustful and valuable decision-making tool, especially for projects being at the design and development phase.