Showing papers in "Chemical Engineering and Processing in 2023"

Development of aerated concrete waste/white cement composite for phosphate adsorption from aqueous solutions: characterization and modeling studies

Abstract: Adsorbing phosphate (PO4−3) from aqueous solutions onto concrete-based construction waste represents a low-cost, nontoxic, and sustainable technique. The novelty of this paper focuses on the adsorption and desorption of PO4−3 from aqueous solutions using autoclaved concrete (AC) chemically activated with white cement (AAC), representing an innovative adsorbent. Pseudo-second-order model better represent adsorption for AC (0.29 mg g−1; pH 6.35) and AAC (0.54 mg g−1; pH 6.53). The experimental data adjusted better with Freundlich and Langmuir models for AC (8.87 mg g−1) and AAC (3.90 mg g−1), suggesting physisorption and chemisorption, respectively. The presence of calcite could promote ligand exchange onto adsorbent surfaces. For desorption, pseudo-first-order model better explained for AC (0.19 mg g−1) and pseudo-second-order model for AAC (0.39 mg g−1). Sips model better fitted the equilibrium data (0.45 mg g−1 AC; 1.97 mg g−1 AAC), related to ionic exchange and electrostatic repulsion. Phosphate adsorption tends to be more reversible in AC. The chemical activation with white cement enhanced the phosphate removal and recovery by the alternative low-cost autoclaved aerated concrete. Finally, AC and AAC presented potential of reducing phosphate with 64.7% and 92.6% for raw wastewater and 83.1% and 84.8% for primary-treated effluent of a corn flour processing, respectively.

Etherification of olefins from catalytic cracking gasoline to increase its octane number

Abstract: This study explores the etherification of the olefins in the Fluid Catalytic Cracking (FCC) gasoline, without previous separation of isoamylenes fraction. The bench- scale experiment demonstrated that etherification performed with Purolite CT-275, a macroporous polymeric ion-exchange resin, and different alcohols (methanol, bioethanol, isopropanol and 1-butanol) produces significant conversion of olefins, even for the heavier C6-C9, so that overall conversion of olefins reaches 70% in reaction with ethanol and 83% with isopropanol. As a result, the Motor Octane Number of the gasoline increases by up to two valuable units. The optimization of the reactive distillation parameters was performed by simulation in CHEMCAD 8 and a process flow was suggested for the etherification sequence, in the FCC unit.

Effect of swirler vane angle on the combustion characteristics of premixed lean hydrogen-air mixture in a swirl micro-combustor

Abstract: This study analyses the influence of swirler vane angle (β) on the combustion characteristics of premixed lean hydrogen-air flame in a swirl micro-combustor via numerical simulations. The results show that lower flammability limit (LFL) under β = 15° is larger than that of β = 0°; and β = 30°, 45° and 60° have very little difference in the LFL, and their LFL are smaller than that of β = 0° Flame anchoring mainly depends on the corner recirculation zone (CRZ) when β is 0° and 15°, and when β exceeds 30°, flame anchoring is chiefly determined by the inner recirculation zone (IRZ). The flame stabilization ability of IRZ is stronger than that of CRZ, but excessive swirling intensity will increase the length of IRZ, which in turn results in a decrease in stabilization ability. Increasing β improves outer wall temperature when inlet velocity is relatively small. Under a larger inlet velocity, an enormous β reduces combustor thermal performance and combustion efficiency due to the downstream movement of flame root and reaction zone. This work helps us to better understand the swirling flame characteristics in micro-combustor and provides guidance for the design and optimization of swirl micro-combustor.

Product composition control based on backpropagation neural network in pressure-swing distillation processes

Abstract: In this paper, an intelligent control strategy based on back propagation neural network (BPNN) is proposed for product composition control in pressure-swing distillation (PSD) processes. A data-driven intelligent controller based on BPNN was combined with PID control instead of traditional composition controllers to avoid the problem that composition is difficult to measure online in real-time. The intelligent controllers are used to predict temperature set point in composition- temperature cascade control by using the process variables easy to measure, e.g., reboiler duty, thus avoiding composition measurement. The critical variables for output prediction are analyzed by correlation analysis to present the relationship between the output variables and input variables, then to train highly correlated variables by BPNN. Two typical triple-columns PSD processes, i.e., Ethanol/THF/Water and ACN/IPA/Water, were used to verify the reliability and accuracy of the intelligent controllers under ±20% of feed flow and composition disturbances. Results demonstrated that the proposed intelligent control strategy presents good dynamic performance without the composition analyzer. This study is significant in improving dynamic performance and solving practical application problems by combining the traditional PID control and data-driven intelligent control.

Recent advances in the intensification of triboelectric separation and its application in resource recovery: A review

Abstract: Triboelectric separation has been widely used as one of the most vital and promising powder processing technologies for resource recovery. Recently, triboelectric separation technology has been developing continuously, and has been widely applied in the fields of coal cleaning, mineral separation and secondary resource recycling (e.g., waste printed circuit boards). In this work, the research progress of triboelectric separation in mineral processing was systematically summarized, including pretreatment of particles, charged process intensification, separation process intensification and its application to coal and mineral separation. Furthermore, effective strategies and new explorations were put forward for the challenges and problems faced by efficient triboelectric separation. This review can provide detailed information for the research status of triboelectric separation for minerals, coal and secondary resources, and offer vital insights for further improvement and development of efficient triboelectric separation technology.

Heat transfer enhancement in a regenerative cooling channel using porous media

Abstract: The endothermic hydrocarbon fuels play an important role in the thermal management of hypersonic scramjet. However, there often involve serious thermal stratifications in the regenerative cooling channel. The present work conducts a two-dimensional cooling channel numerical simulation with the addition of porous media using a unique global chemical kinetics model to clarify the increase of the total heat sink of hydrocarbon fuels. It is proposed that the addition of porous media is a coupling process, which not only enhances heat transfer, but also will bring resistance to heat. Therefore, the energy source term is included in the numerical simulations, which makes our calculations closer to the actual working condition compared to the previous numerical modeling. The simulated results indicate that compared to the smooth channel, the thermal stratifications are relieved in the cooling channel with the addition of porous media, while the thermal cracking of n-decane is inhibited due to the decrease of the wall temperature. In addition, with the decrease of porosity of porous media, the total heat sink of fuel increases. The heat transfer coupling rule of porous media is studied by placing porous media at different positions, and the optimal placement position is found.

A novel technology for optimizing dissolved air flotation unit efficiency via secondary saturation of the flotation cell with air bubbles and thin-layer settling

Abstract: Specific ways to improve the technology for flotation (DAF) wastewater treatment have been determined. Prospects to increase functioning of DAF units via using thin-layer cells, and improving the hydraulic size of the emerging flotation aggregates have been shown. The latter is feasible due to secondary saturation of the flotation cell with air bubbles of 0.1–0.3 mm diameter floating in laminar flow regime and creating light turbulence thereof. The possibility of obtaining an air-water mixture with air bubbles during their breaking up in the annular space of the saturator-separator is experimentally proven. It is feasible to separate the air bubbles from the major fluid flow in the centrifugal field due to rotational and translational motion of the separated mixture. It is established that converting the Q-H vane pump characteristics, which provides for pumped flow circulation and useful flow selection for the two medium-pressure ejectors operating in series, allows to: ensure stable air ejection from the atmosphere; significantly increase the vane pump head H via reducing the supplied useful flow; exclude a compressor and replace an expensive high-pressure pump with a lower operating pressure one.

Process intensification for decentralized production

Abstract: In this short paper I give my perspective on what in my opinion is fundamentally Process Intensification (PI), and what the practical future of process intensification may be. Some of the definitions which have been given over the years to process intensification are critically revisited, and a somewhat modified definition which focuses on the nature (quality) of the technology, as opposed to only its quantifiable measures, is suggested. I then suggest that the main impact PI technologies will make is in decentralized (or distributed) production. A few key processes, currently of most interest, which if distributed would create industrial suction for PI technologies, are delineated. These technologies have a high potential to enable the transition from large scale centralized production to distributed production. Keywords: Distributed production, Process intensification, Energy, Hydrogen, CO2 utilization,

Experimental study on reactor scale-up for microwave-assisted pyrolysis of methyl ricinoleate

Abstract: The microwave-assisted pyrolysis reactor with microwave absorbent bed can work continuously and efficiently to pyrolysis reactions, which makes it potential for reactor scale-up. In this paper, the scale-up of microwave-assisted pyrolysis reactor using silicon carbide (SiC) as microwave absorbent bed that was used for methyl ricinoleate (MR) pyrolysis was studied. The microwave power, SiC bed diameter and MR feed rate were enlarged from 1 kW, 126 mm and 0.9 kg/h for the lab-scale reactor to 7 kW, 580 mm and 7.0 kg/h for our self-designed scale-up reactor, respectively. The results show that temperature distribution of the scaled up SiC bed surface before feeding of MR was uniform and stable, which provides favorable conditions for efficient pyrolysis reaction on the bed surface. The selectivity and yield of the target product undecenoic acid methyl ester were 75.55% and 63.08%, respectively that reached the lab-scale test results. It needs to be emphasized that the scale-up process of microwave-assisted pyrolysis of MR has no obvious scale-up effect by using the microwave intensification heating and the microdroplet rapid heating technology. This study will provide guidance for the large-scale application of the microwave-assisted pyrolysis reactor in chemical industry.

Towards responsive gas-solid operations: Oscillating and vortex flows

Abstract: Working towards a circular economy requires the ability to introduce clean energy sources, new vectors and storage methods into classic process infrastructure. An efficient contact between gases and solids is at the core of this task across manufacturing, environmental and energy sectors. New integrated processes start to move away from the use of the classic unit operations in chemical engineering into more flexible, multifunctional units, but intensified contact chambers are often too specialised. New design concepts must focus not only on the efficiency of a device, but in creating robust, flexible solutions that can adapt to changing targets and perform multiple functions to widen the scope of advanced optimization and control strategies. In this work, I briefly discuss the role of responsive devices in the design of sustainable processes involving gas-solid flows, and I provide a quick overview of the role of structured fluidization paying special attention to two promising pathways: dynamically structured oscillating fluidised beds that deliver homogeneous, responsive, and scalable solid mixing at low velocity, and the potential evolution of emerging vortex devices into rotational “moving” beds working at high interfacial velocity.

Hydrogen ortho-para conversion: process sensitivities and optimisation

Abstract: Liquid hydrogen has potential as a storage vector for large-scale hydrogen transportation. Hydrogen liquefaction is however a highly energy intensive process, particularly due to the necessary exothermic spin-isomer conversion from ortho- to parahydrogen. We explore the operation of the main cryogenic plate-fin heat-exchangers (PFHXs) used in hydrogen liquefaction; simultaneous dynamic processes occurring within the PFHX include the heterogeneously catalysed spin-isomer conversion, heat transfer and pressure loss. In this work, these coupled processes are simulated for a 100 tonne/day hydrogen reactant cooled by a helium refrigerant in a PFHX. For the process configuration utilised in this work, a reactor volume of 24.0 m3 and a coolant flow rate of 600 tonne/day were necessary to achieve and outlet parahydrogen fraction of 0.99. Pressure drop through the PFHX packed bed was consistently negligible. We also explored the sensitivity towards model parameters. The outlet parahydrogen fraction is determined to be considerably (∼10 times) more sensitive to reaction rate kinetics relative to heat transfer: therefore, the reactor geometry will be primarily determined by conversion kinetics. The current quantitative understanding of these rate kinetics is however limited. Future experimental research thus needs to focus on quantifying ortho- to parahydrogen kinetics. Destination: Chemical Engineering and Processing: Process Intensification

Recent Advances in Delivery Systems Optimization using Machine Learning Approaches

Abstract: Nowadays, the researchers delve into the intricacies of machine learning (Artificial Neural Network (ANN), Genetic algorithm (GA), support vector machines (SVM), K-means clustering, decision trees, etc) to uncover their potential for implementation in the development of optimized food delivery systems. They searched for a ready-to-use machine learning approach to be applied. Thus, this review presents a comprehensive overview of the current machine learning approaches and algorithms available for optimizing food delivery systems. It is groundbreaking as it is the first of its kind to specifically concentrate on this topic. The latest advancements in this area have been carefully scrutinized, and the most viable techniques and methods have been identified to enhance food delivery systems. This review will be of great value to biological and chemical researchers as well as supply chain management professionals, as it offers a clear roadmap for employing different approaches of ANN, GA, SVM, K-means clustering, decision trees, in conjunction with response surface methodology (RSM), to enhance the accuracy and efficiency of nanoparticles and nanoemulsions in food delivery systems.

Challenges and opportunities of process intensification for the conversion of waste CO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si42.svg" display="inline" id="d1e74"><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> to liquid fuels

Abstract: Electrochemical conversion of waste CO2 has emerged as a solution to integrate carbon capture with the production of high-value chemicals or synthetic fuels, reducing the dependence on fossil fuels while tackling the issue of intermittent availability of electricity from renewables. The main limitations of CO2 conversion are that its electro-reduction to C2+ products is difficult to control and characterized by low selectivies. On the contrary, processes for CO electro-reduction to C2+ products, characterized by high selectivities and reaction rates, have been demonstrated. The interesting opportunity is therefore emerging of developing multi-step processes in which CO2 is converted to value-added C2+ products using CO as intermediate. If the CO2 and subsequent CO electro-reduction processes could be carried out in the same location, issues related to transport and storage of CO could be overcome. In addition, the process could allow flexible production of both CO and C2+ products, depending on consumer demand. This Perspective presents an overview of CO2 capture and its subsequent two-step electro-reduction to C2+ products, with a focus on electrochemical methods and process integration, to increase the environmental and economic benefits of CO2 utilization. Integrating waste CO2 management and energy conversion, while reducing the problem of transport and storage of energy or dangerous compounds is a prime example of process intensification applied to CO2 emissions reduction.

Enhanced castor seed oil extraction assisted by the synergistic effect of ultrasound and microwave: Impact on extraction effectiveness and oil quality

Abstract: The present study first time utilizes synergistic effect of ultrasound and microwave for oil extraction from castor seeds, with methanol as solvent. Taguchi's orthogonal array is selected as a tool for design of experiment for castor oil extraction through mechanical stirring, ultrasound, and hybrid (ultrasound + microwave) intensification techniques. The maximum extraction yield effectiveness of 98.37% is achieved based on optimized process conditions: 45 s grinding time, 12:1 solvent-to-seed ratio (v/w), 30 min extraction time, and 50 °C temperature. Along with the yield, significant enhancement in extracted oil quality in terms of oxidation stability and chemical composition is observed. The chemical composition of oil extracted through a hybrid technique shows a lower unsaturation level than ultrasonication. Ultrasound and hybrid technique both significantly increased proportion of ω-6 and ω-9 fatty acids, which has industrial as well as medicinal values. The viscosity of the oil extracted through hybrid solvent extraction is 199 ± 6 cp, which is significantly lower than that of a crushing-based technique (279 ± 6 cp). The energy consumption for the hybrid reactor is reduced by up to 40 % and 28 % than conventional mechanical stirring and ultrasound techniques, respectively. The developed process is industrially viable and environmentally sustainable.

Investigation of exhaust emissions and performance of a diesel engine fueled with preheated raw grape seed oil/propanol blends

Abstract: The enrichment of alternative fuels with oxygen in diesel engines is one of the influential techniques utilized to improve performance and lower emissions. This work analyzed the influences of grape seed oil-propanol fuel mixture, which can be an alternative to diesel fuel, on diesel engine. Grape seed oil (GSO), which was used raw, was extracted from grape seeds by cold pressing method. In order to improve physical and chemical attributes of fuel mixtures, preheating process was applied. The engine tests were realized in an air cooled single cylinder diesel engine. GSO was stirred with diesel fuel in volumes of 10% and 30% and also 5% propanol was added. In this study, CO, NOX, smoke, HC, BSFC, EGT, BTE, vibration and noise parameters of diesel engine were taken into consideration. Moreover, thermal images of the engine were also recorded. The results indicated that BSFC, CO, smoke and HC diminished but NOX, BTE, EGT, vibration and noise increased in the preheated and propanol added test fuels. Preheating process for grape seed oil ensured a convenient fuel flow and decreased the oil viscosity and propanol addition contributed to the enrichment of the fuel in terms of oxygen.

Incorporation of silver recovery with electricity generation through methanol-Ag+ coupled redox fuel cell

Abstract: The recovery of noble metal ions from wastewater without energy consumption is of utmost importance. Herein, a methanol-Ag+ coupled redox fuel cell (CRFC) was developed to realize silver removal and electricity generation simultaneously. In this system with alkaline methanol as fuel on the anode, Ag+ in catholyte was reduced. The highest open circuit voltage of 1.28 V and maximum power density of 17.4 W·m−2 were achieved at 0.1 mol·L−1 Ag+ (pH=1.1). More than 90% Ag+ can be removed in 6 h, and over 60% of cathodic efficiency was achieved simultaneously when using Ag+ as electron acceptors. Morphology analysis showed that dendritic Ag particles were loosely deposited on the cathode after 2 h operation. The size of the silver dendrites increased with Ag+ concentration increase. Eventually, a fed-batch mode was conducted to confirm that either the Ag+ is efficiently reduced or the energy in chemicals has been sustainably retrieved in electricity.

How fundamental knowledge on mass transfer in bubbly flows will help process intensification

Abstract: We are in danger of losing our current standards of living due to the depletion of natural resources. It is essential to decrease the amount of waste produced. In reactor engineering, the waste production is caused by the formation of byproducts. To increase the selectivity of the reactor, the fluid dynamics should benefit the intrinsic reaction kinetics, which can only be done when each molecule has exactly the same experience. The mass transfer from a bubble is generally assessed solely by the overall mass transfer coefficient from the bubble. However, the concentration profile is far from uniform when the mass is transferred from the bubble. The obtained concentration profile seems to be confined by the hydrodynamic wake of the bubble. The obtained structures are quite stable and not easily disturbed by other bubbles. This leads to large concentration gradients in the bulk, which prevents the molecules in the liquid to have the same or a similar experience in the reactor. As this will have a large impact on the selectivity when consecutive reactors are considered. It would be essential in the future to study these local mixing profiles in bubbly flows in particular and in multi-phase flows in general.

Experimental study on the flow behaviors in a vane-type separator

Abstract: The axial separator for gas-liquid separation receives amounts of attention due to its compact geometry. Since the inlet flow pattern does a significant impact on the separation performance of the centrifugal separator, it is necessary to figure out the flow behavior inside the separator and give some guidance to the practical application. In this paper, a vane-type separator was used to investigate the flow behaviors inside the separator at different inlet flow patterns. Pre-separation is found in the swirler, which is caused by the curving flow channel. Swirling chain flow, swirling intermittent flow and swirling annular flow inside the separation chamber are observed in the experimental range. Besides, the reason for the formation of swirling chain flow is explained. The phenomenon of bubble accumulation can be eliminated by opening the first light phase outlet. Then the effect of first light phase outlet was studied further. Additionally, a multi-stage vane-type separator was tested to study the flow behavior in the two swirl chambers. From the experimental investigation, it is suggested that the vane-type separator would better be applied in high liquid velocity and low gas void fraction condition.

Microwave-assisted sustainable synthesis of biodiesel on Oryza sativa catalyst derived from agricultural waste by esterification reaction

Abstract: The present study aims to confirm the feasibility of O. sativa husk for the fabrication of high-performing heterogeneous-based carbon catalysts. A series of catalysts are fabricated by a facile carbonization method followed by sulfonation. The heterogeneous catalysts derived from agricultural wastes were used in the esterification process to synthesize fatty acid methyl ester (FAME). The sulfuric acid concentration was varied from 2 to 10 mM L–1 to study its influence on the FAME yield. The carbonized O. sativa husk treated using 10 mM L–1 of H2SO4 shows high acid density (2.26 mmol/g) and S-content (5.31%). Under various optimized processes, the FAME yield reached a maximum of 99.6 ± 0.2% {60 min at 80 °C, 8 wt.% catalyst dosage, and a 24:1 molar ratio of methanol to oleic acid (OA)}. The conversion of oleic acid into methyl oleate also depends on the carbon chain length of alcohol. It was found that as the carbon chain length increases, the FAME yield decrease. The solid acid catalyst shows an excellent FAME yield of 99.6 ± 0.2% and an activation energy of 76.11 kJ mol–1, whereas the value of pre-exponential factor A is 1.4 × 1010 min−1. The as-synthesized catalyst is reusable for up to seven cycles because of its high total acid density and S-content. An ecologically friendly and promising strategy for green fuel generation shown in this work by using a solid renewable acid catalyst generated from agricultural waste.

Effect of Ultrasound on Mass Transfer during Vacuum Impregnation of Low-Porous Food Materials on the Example of Potato (Solanum Tuberosum L.)

Abstract: Vacuum impregnation (VI) is a process that allows modification or enrichment of porous food products with vitamins, minerals, functional ingredients, etc. There are many factors that hamper mass transfer during VI, e.g. low porosity, composition of the matrix, processing pressure and time, etc. The objective of this study was to evaluate the effect of starch on blocking mass transport during VI, and the potential of ultrasound as a factor enhancing mass transfer. The effectiveness of VI was evaluated on the basis of the ascorbic acid content (AAC), a marker compound introduced from the solution. It was found that starch can hinder the mass transfer but ultrasound intensifies the flow of the impregnating solution (16–67% increase in AAC). The quantitative effects, however, depended on the application stage. This may be explained by the different types of cavitation (stable or transient) dominant at different pressures. Importantly, the negative effects of VI on the analyzed quality parameters analyzed (e.g., color, texture, structure-forming compound content) were not stated. The results indicated that the effectiveness of VI in low-porous and starch-rich materials may be increased by applying ultrasound, but more research is required to analyze the stability of the compound introduced during preservation processes.

Plasmon enhanced photocatalytic degradation of 4-chlorophenol using zinc oxide nanorods decorated with gold nanoparticles as supported catalysts under natural sunlight

Abstract: The photocatalytic degradation of 4-chlorophenol (4-CP) was evaluated under natural sunlight using zinc oxide nanorods (ZnO NRs) and gold nanoparticles (AuNPs) decorated ZnO NRs catalysts. Microwave-assisted hydrothermal growth of ZnO NRs followed by photoinduced deposition of AuNPs on ZnO NRs was carried out to fabricate the ZnO-Au catalysts. The photocatalytic degradation of 4-CP with different AuNPs sizes and surface coverage obtained from varying Au loading on ZnO NRs was studied. 0.1 mM AuNPs concentration exhibited the best result, with a degradation efficiency of 97% for 10 ppm of 4-CP within 180 min. The degradation enhancement for the ZnO-Au catalysts was owing to enhanced absorption in the visible region. The visible-light-induced localized surface plasmon resonance property of AuNPs reduced the recombination and promoted the electrons and holes separation. The substantial change in the binding energy of the valance band maximum exhibited the charge transfer from AuNPs to ZnO NRs. Photocatalytic degradation of four different concentrations (10, 50, 100, and 200 ppm) of 4-CP was studied. During the photocatalytic degradation, various hydroxylated intermediates formed, namely hydroquinone, benzoquinone, 4-chlorocatechol, and 4-chlororesorcinol. The photocatalytic results indicate that the ZnO-Au catalyst is a promising candidate for environmental decontamination of organic pollutants in the aqueous media.

Electric Field Efficiently Enhanced Thermochemical Cleaning for Oil Recovery from Oily Sludge

Abstract: Electric field efficiently enhanced thermochemical cleaning for oil recovery from oily sludge (OS) was proposed in this work, which was inspired by electro-kinetic (EK) remediation of sludge. The effects of different factors (e.g., current density, the concentration of solution, liquid to solid ratio) on oil removal efficiency of OS were investigated. It was found that the oil removal efficiency of OS could reach more than 60 wt% by electric field enhanced the instability of metastable emulsion system with a minimum energy consumption of 604.8 J/g. The content of the residual oil in the sludge could be lowered from 8.6 wt% to 2.8 wt% after being treatment under the optimum conditions, which showed a 143 wt% maximum increase in oil removal effiency compared to non electric field treatment. The recovered oil mainly consisted of long chain alkanes, which had high recovery value. Based on characterization and analysis results, the mechanism was speculated to provide guidance for the resource utilization of OS with low energy consumption in industrial processing.

Optimization and sensitivity analysis of a multi-product solar grade silicon refinery: Considering environmental and economic metrics

Abstract: Today, one of the main lines of solar energy development is the creation of environmentally friendly, waste-free and inexpensive solar grade silicon production technologies. Presently, the main solar grade silicon production technologies are based on the reduction of silicon hydrogen chloride compounds (trichlorosilane, tetrachlorosilane and silane). This paper will examine the results of the optimization of a multi-product silicon refinery, where the objective functions are Profit and Eco-indicator99. Seven scenarios are considered for the work. The best scenario (S4) showed a tendency to maintain a balance between Profit (98.66 M$/y) and the environmental indicator Eco99 (6.04 MP/y). Similarly, a sensitivity analysis was carried out by varying the market prices of each of the products obtained (solar grade silicon, TEOS at different purities, and chlorosilanes) with an increase of 10% and a decrease of 10%, resulting in multiple production scenarios depending on what the market dictates. By increasing the cost of solar grade silicon by 10%, the multi-product refinery achieves the highest profit (151.84 [M$/y] with an environmental impact of 9.8 [MP/y]), and by decreasing the cost of the same silicon by 10%, the lowest environmental impact is achieved (36 [M$/y] with an environmental impact of 3 [MP/y]).

High gravity wet purification of fine particles and naphthalene in gas

Abstract: Coke oven gas contains fine particles and naphthalene, these impurities are easily deposited in equipment and pipelines and cause blockage. Moreover, it is extremely harmful to the human health and environment. In this paper, a pilot-scale experimental system was built employing a cross-flow rotating packed bed to explore the purification ability of the high gravity wet separation technology for naphthalene and the mixture of fine particles and naphthalene. It was shown that under the operating conditions of inlet gas naphthalene content of 5 mg/m3, high gravity factor of 83.70, gas velocity of 1.43 m/s and liquid spray density of 7.19 m3/(m2·h), the high gravity wet purification efficiency of naphthalene was 89.53%. At the inlet dust concentration of 50 mg/m3, the naphthalene content of 5 mg/m3, the gas velocity of 1.43 m/s, the high gravity factor of 83.70 and the liquid spray density of 6.0 m3/(m2·h), the purification efficiency of fine particles was as high as 99.23%, and the purification efficiency of naphthalene was 82.87%. It can be seen that high gravity wet purification technology possess a great potential for industrial application with better removal of naphthalene-containing gas as well as gas containing fine particles and naphthalene.

Methane reforming in microchannels: Application to the methanol synthesis

Abstract: Methanol as a simple hydrocarbon containing oxygen is one of the most consumed gas chemicals all around the world. It is a versatile fuel that can be used in fuel cells such as direct methanol fuel cells and downstream proton exchange membrane fuel cells, combustion engines, or even as on-board hydrogen storage. In the chemical industry, methanol is also a vital intermediate employed in a variety of applications and feedstocks. The production of heat upon the synthesis of methanol enhances the temperature of the reactor, lowers the conversion rate, and hastens the deactivation of the catalyst. More isothermal process conditions can be achieved by using microchannel reactors in the methanol synthesis. Because of the small channel's dimensions, the reactor has a high surface-to-volume ratio, which greatly enhances the heat and mass transfer. The rapid heat and mass transfer of substances caused by diffusion in small lateral dimensions results in narrower residence-time distribution in the reactor for gas-phase reactions. The purpose of this work is to investigate the methane-reforming process in microchannels with application in the methanol synthesis process in recent years.

Microwave-assisted synthesis of alkyd resins using response surface methodology

Abstract: Long alkyd resins for artistic applications were prepared by microwave synthesis of high-unsaturated vegetable oils. In this work, response surface method using split-plot optimal design was applied to optimize alkyd resin's acid value. Oil vegetable source (Sacha inchi and Linseed oil), temperature (200–240 °C), reaction time (4–12 min), and benzoic acid were evaluated as independent variables. Long alkyds resins with lower acid value considered optimal were characterized by FTIR and 1H-RMN techniques. Physicochemical properties, like color, viscosity, and drying time were assessed as well. Synthesis of alkyd resins from sacha inchi oil required less time and energy in comparison with linseed oil ones. Alkyd resins prepared with Sacha inchi oil for 210 °C and 12 min using 11.67 kJ/g at esterification stage provided a lower acid value (14 mgKOH/g), viscosity (W-X bubble Gardner), and Gardner scale color (11) in comparison with linseed oil.