Hydrodeoxygenation is an essential process for producing liquid transportation fuels. In this study, the effects of CoMo/γ-Al2O3 catalysts form and loading ratio on the hydrodeoxygenation upgrading of bio-oil were investigated in a batch reactor. Raw bio-oil was first oxidized with hydrogen peroxides and oxone to obtain the oxidized bio-oil with reduced levels of aldehydes and ketones, increasing the organic liquid yield during hydrodeoxygenation by suppressing the coke formation. CoMo/γ-Al2O3 was selected as the catalyst because of its low cost and commercial availability. The effect of the reduction and sulfidation of CoMo/γ-Al2O3 catalyst on the hydrodeoxygenation of the oxidized bio-oil was compared. The effect of the catalyst loading ratio on bio-oil hydrodeoxygenation using sulfided CoMo/γ-Al2O3 catalysts was also investigated. The research results showed that the sulfided CoMo/γ-Al2O3 catalyst facilitated the formation of hydrocarbons, while the reduced CoMo/γ-Al2O3 catalyst pro... [more]

The usage of palm oil empty fruit bunches (EFBs) in the gasification process adds value to the empty bunches as a renewable energy source. In this study, we design and manufacture a new updraft type of gasifier reactor without a blower so that it does not require electric power in its operation, but uses power from engine suction. Our test results compare the use of biomass waste in conjunction with diesel fuel to run a diesel power plant for 20 min at a load of 10,000 W: diesel with coconut shell charcoal (350 mL), diesel with acacia wood charcoal (380 mL), and diesel with EFB charcoal (400 mL). The test shows that the highest efficient and the most optimal biomass in the gasification process is coconut shell charcoal, because coconut shell charcoal has a dense structure and, at the time of the experiment, the coconut shell charcoal was filled 15 cm below the gas outlet pipe hole. From the standpoint of the economic value of the gasifier reactor that is proposed in this study, the res... [more]

This paper analyzed the problems associated with physical exergy splitting, and based on this, presented a new splitting method. This new method splits the physical exergy into three parts according to the feasible working ways, i.e.,: the direct, indirect, and adaptive exergy. The computational method and the physical meaning of the three exergy parts were presented in detail in terms of graphic representation and mathematical derivation. Then, it was applied to the exergy analysis of a thermal power cycle. The results show that compared with the conventional method which splits the physical exergy into thermal and mechanical parts, the current exergy splitting method can better represent the change rule of the working ability of the real working stream in the cycle and the influence of some operation parameters, such as the turbine inlet temperature, on the real working ability. The study suggests that the new method can make the exergy analysis more helpful and guidable in its appli... [more]

Ionic conductivity of the polyethylene oxide-LiClO4 (PEOLiClO4) solid polymer electrolyte (SPE) films with an EO:Li ratio (n) of 10, 12, 15, as well as the hybrid composite solid polymer electrolyte (CSPE) films of PEOLiClO4 containing 50 wt% of cubic-Li7La3Zr2O12 (LLZO) sub-micron sized particles, have been studied by varying Li-salt content in the films. The complex AC dielectric permittivity and conductivity data obtained from electrical impedance measurements were fitted using a generalized power-law, including the effects of electrode polarization applied at low AC frequencies to obtain various relaxation times. In addition to increased mechanical and thermal robustness, the CSPE films show higher values of ionic conductivity, >10−4 S/cm at room temperature compared to those of SPE films with n = 12 and 15. On the contrary, the ionic conductivity of CSPE with n = 10 decreases by a factor of three compared to the corresponding SPE film due to increased polymer structural reorientat... [more]

Systems engineering crosses multiple engineering disciplines for the design, control, and overall management of engineered systems [...]

The design of bipolar plates is critical for improving the performance of proton exchange membrane fuel cells (PEMFCs). In this research, a new additional outlet based on a PEMFC’s parallel flow field was proposed, and three different positions of outlet were designed on the target side of gas flowing in parallel channels. The results revealed that the additional outlets are able to increase the gas speed through channels near the additional outlets, which results in a lower water saturation and a more uniform distribution of oxygen concentration at the interface between the catalyst layer (CL) and gas diffusion layer (GDL). With the variation of the outlet position in the target side, it was found that the additional outlet set in the middle of the target side exhibits the highest increase of peak power density, namely, 13%. Furthermore, the optimal position of the additional outlet was proved to be suitable for PEMFCs with various active surface areas, indicating the universality of... [more]

Facing the current energy structure urgently needs to be transformed, heat exchanger network (HEN) can implement heat recovery and cost reduction by the arrangement for heat exchanges between cold and hot streams. The plenty of integer and continuous variables involved in HEN synthesis cause the results to be easily trapped in local optima. To avoid this situation, the mechanism of accepting imperfect solutions is added in a novel algorithm called Random Walk Algorithm with Compulsive Evolution. However, several potential solutions maybe abandoned by accepting imperfect solutions. To maintain the global searching ability, and at the same time, protecting the potential solutions during the optimization process, the limitations of accepting imperfect solutions are investigated in this work, then a back substitution strategy and elite optimization strategy based on algorithm are proposed. The former is to identify and adjust the inferior individuals in long-term stagnation while the latte... [more]

Fecal pollution, commonly detected in untreated or less treated sewage, is associated with health risks (e.g., waterborne diseases and antibiotic resistance dissemination), ecological issues (e.g., release of harmful gases in fecal sludge composting, proliferative bacterial/algal growth due to high nutrient loads) and economy losses (e.g., reduced aqua farm harvesting). Therefore, the discharge of untreated domestic sewage to the environment and its agricultural reuse are growing concerns. The goals of fecal pollution detection include fecal waste source tracking and identifying the presence of pathogens, therefore assessing potential health risks. This review summarizes available biological fecal indicators focusing on host specificity, degree of association with fecal pollution, environmental persistence, and quantification methods in fecal pollution assessment. The development of practical tools is a crucial requirement for the implementation of mitigation strategies that may help c... [more]

In Korea, to prevent the extinction of Glehnia littoralis, a cultivation method to improve productivity is being studied and quality maintenance technology is required after harvest. The objective of this study was to determine the effect of MAP on the postharvest quality of G. littoralis. The control showed a weight loss rate of more than 5% after 3 days of storage and lost its marketability, whereas MAP treatment (PE or MPE) showed a weight loss rate of about 2−3% during storage for more than 30 days. In the control, MDA and electrolyte leakage increased due to chilling injury. The total chlorophyll content was low and remained constant until about 23 days of storage in the PE treatment group and 15 days in the MPE treatment group. Among the phenolic compounds, chlorogenic acid, rutin, isoquercetin, and nicotiflorin were maintained at significantly higher levels in the PE than in the MPE. In addition, bergapten showed a highly significant upward trend in the MPE, especially after 25... [more]

The present paper reports experiments on microwave heating of a carbonate oil-containing rock sample in the presence and absence of an iron-magnetite-based nanocatalyst. It has been shown that the used catalyst improves the processes of destructive hydrogenation of resins and asphaltenes compounds in the oil. The chemical reactions analysis demonstrated a decrease in asphaltenes content and in their molecular weight, which increases the filtration capacity of the oil fluid in the reservoir rock porous medium. Moreover, the content of non-extractable organic matter in the rock sample after experiments and after oil extraction was determined. It has been found that the absence of the catalyst causes the least increase in the content of non-extractable organic matter in the rock. This fact is related to the intensive processes of resinous-asphaltene compounds destruction especially at the level of peripheral groups which are the most condensed fraction, and hence leads to a decrease in th... [more]

Battery cell production is a complex process chain with interlinked manufacturing processes. Calendering in particular has an enormous influence on the subsequent manufacturing steps and final cell performance. However, the effects on the mechanical properties of the electrode, in particular, have been insufficiently investigated. For this reason, the impact of different densification rates during calendering on the electrochemical cell performance of NMC811 (LiNi0.8Mn0.1Co0.1O2) half-cells are investigated to identify the relevant calendering parameters. Based on this investigation, an experimental design has been derived. Electrode elongations after calendering in and orthogonal to the running direction of the NMC811 cathode are investigated in comparison with a hard carbon anode after calendering. Elongations orthogonal to the machine direction are observed to have no major dependencies on the compaction rate during calendering. In the machine direction, however, significant elongat... [more]

Crude glycerol, a biodiesel industry byproduct, and corn steep liquor (CSL) derived from a starch industry, were used as carbon and nitrogen sources, respectively, for lipid production, using the heterotrophic microalga C. cohnii grown in a bench bioreactor, in a batch culture. The maximum biomass concentration, lipid content and lipid productivity attained were 5.34 g/L, 24.6% (w/w Dry Cell Weight-DCW) and 0.016 g L−1 h−1, respectively. Flow cytometry analysis was used to evaluate the impact of these substrates on the microalgae cells. A high proportion of intact cells with enzymatic (esterases) activity (>50%) was present throughout the cultivation time course. These results indicate that crude glycerol and CSL can be used in the medium formulation for DHA and lipid production using this microalga, which reduce the process costs in an expected maximum of 84%.

There are cases where the output of renewable eappennergy (RE) is curtailed due to an increase in the share of RE. Typically, wind power (WP) is curtailed due to oversupply and low loads at midnight. However, there are cases where the output of WP is limited during the daytime due to the increase in the share of photovoltaics (PV). In the current electricity market, as the share of PV is increased, the curtailments of WP will be increased further, which will add to the difficulties experienced by wind farm operators. This paper proposes a supervisory power coordination scheme. The main purposes are to prevent the penetration of extra power from REs into the grid; thus, the curtailments can be prevented. In order to make it feasible, the proposed scheme is to design a grid-connected microgrid system to be operated only in response to loads and virtual power plant (VPP) requests. The effectiveness of the proposed scheme was verified by simulation studies conducted in the MATLAB/Simulink... [more]

What are the benefits of simulation-driven design and optimization of stacking processes in battery cell production? This question is addressed within the scope of the paper. This work proposes a method to reduce the effort for model-based design and optimization. Based on three case studies which originate from the development of high-speed stacking processes, this paper illustrates how the relevant loads on the intermediate products are determined with the help of the method. Subsequently, it is shown how the specific material models for battery electrodes and separators are identified, created and validated, as well as how process models are created and process limits are identified and optimized. It was possible to prove how process simulations can be used to minimize the effort required to validate developments and to efficiently determine optimized process parameters for a format and material change in a model-based manner. Consequently, more and more model-based processes should... [more]

In this paper, biodiesel was used as an alternative fuel to investigate the combustion and emission characteristics of a four-stroke diesel engine, in terms of cylinder pressure, heat release rate, cylinder temperature, brake thermal efficiency, brake specific fuel consumption, nitrogen oxide, soot, carbon monoxide, and hydrocarbon. Firstly, a diesel engine cylinder model was developed by AVL-Fire software coupled with CHEMKIN code to simulate the injection and combustion of biodiesel with a kinetic mechanism with 106 species and 263 reactions. Then, the simulation model was validated by experimental results under 100% and 50% load conditions and used to simulate the combustion process of a diesel engine fueled with pure diesel, biodiesel, and biodiesel−diesel blends with 10%, 20%, 30% biodiesel by volume, respectively. The results showed that the brake specific fuel consumption increased with the increase of mixed biodiesel ratio. The brake specific fuel consumptions of B10, B20 and B... [more]

Natural gas (NG) direct injection (DI) technology benefits the engine with high efficiency and clean emissions, and the high-pressure gas fuel injection process causes crucial effects on the combustion. This study presents an optical experimental investigation on the high-pressure methane single-hole direct injection and premixed ignition combustion based on a visualization cuboid constant volume bomb (CVB) test rig. The experimental results show that the methane jet process is divided into two stages. The methane gas jet travels at a faster speed during the unstable stage I than that during the stable stage II. The injection pressure causes more influence on both the jet penetration distance and the jet cone area during stage II. The methane jet premixed flame is a stable flame with a nearly spherical shape, and its equivalent radius linearly increases. The methane jet premixed flame area also increases while the flame stretch rate declines. The methane jet premixed flame velocity ris... [more]

Adsorption thermodynamic characteristics are an important part of the methane adsorption mechanism, and are useful for understanding the energy transmission mechanism of coalbed methane (CBM) migration in coal reservoirs. To study the effect of coal pore characteristics on methane adsorption heat, five different types of rank coals were used for low-pressure nitrogen, low-pressure carbon dioxide, and methane adsorption experiments. Pore structure and adsorption parameters, including maximum adsorption capacity and adsorption heat, were obtained for five coal samples, and their relationships were investigated. The results show that the low-pressure nitrogen adsorption method can measure pores within 1.7−300 nm, while the low-pressure carbon dioxide adsorption method can measure micropores within 0.38−1.14 nm. For the five coal samples, comprehensive pore structure parameters were obtained by combining the results of the low-pressure nitrogen and carbon dioxide adsorption experiments. Th... [more]

Hydropower units are usually operated in non-design conditions because of power grid requirements. In a partial-load condition, an inter-blade vortex phenomenon occurs between the runner blades of a Francis turbine, causing pressure pulsation and unit vibration, which hinder the safe and stable operation of power stations. However, the mechanism through which the inter-blade vortex generation occurs is not entirely clear. In this study, a specific model of the Francis turbine was used to investigate and visually observe the generation of the blade vortex in Francis turbines in both the initial inter-blade and vortex development zones. Particle image velocimetry was used for this purpose. In addition, we determined the variation law of the inter-blade vortex in the Francis turbine. We found that the size and strength of the inter-blade vortex depend on the unit speed of the turbine. The higher the unit speed is, the stronger the inter-blade vortex becomes. We concluded that the inter-bl... [more]

A systematic modeling approach was scrutinized to develop a kinetic model and a novel monolith channel geometry was designed for NH3 selective catalytic reduction (NH3-SCR) over Cu-ZSM-5. The redox characteristic of Cu-based catalysts and the variations of NH3, NOx concentration, and NOx conversion along the axis in porous media channels were studied. The relative pressure drop in different channels, the variations of NH3 and NOx conversion efficiency were analyzed. The model mainly considers NH3 adsorption and desorption, NH3 oxidation, NO oxidation, and NOx reduction. The results showed that the model could accurately predict the NH3-SCR reaction. In addition, it was found that the Cu-based zeolite catalyst had poor low-temperature catalytic performance and good high-temperature activity. Moreover, the catalytic reaction of NH3-SCR was mainly concentrated in the upper part of the reactor. In addition, the hexagonal channel could effectively improve the diffusion rate of gas reactants... [more]

Jet engines are commonly used in aeronautical applications, and are one of the types of gas turbine engines. The circulation of air releases heat energy to expand the volume of hot fluids and impact the turbine wheel to generate power of hot gases. The present study investigates the potential of using ultrasonic atomization technology to assist in the combustion process. An experimental rig was set up to determine the performance of jet engines using ultrasonic droplets. A gas analyzer was used to measure various greenhouse emissions of exhaust gas. The performance of the engine was tested under three load levels (high, medium, low), starting from 10 psi at a steady state, to the minimum value. A significant result was tested for a low value of nitrogen monoxide at the three levels of load, and a specific result was tested for an efficiency value of 2% at the three levels of load. Carbon dioxide was found to decrease at the low load level. The use of an ultrasonic atomization device to... [more]

Constrained optimization problems (COPs) are widely encountered in chemical engineering processes, and are normally defined by complex objective functions with a large number of constraints. Classical optimization methods often fail to solve such problems. In this paper, to solve COPs efficiently, a two-phase search method based on a heat transfer search (HTS) algorithm and a tandem running (TR) strategy is proposed. The main framework of the MHTS−TR method aims to alternate between a feasible search phase that only examines feasible solutions, using the HTS algorithm, and an infeasible search phase where the treatment of infeasible solutions is relaxed in a controlled manner, using the TR strategy. These two phases play different roles in the search process; the former ensures an intensified optimum in a relevant feasible region, whereas the latter is used to introduce more diversity into the former. Thus, the ensemble of these two complementary phases can provide an effective method... [more]

In this paper, the effects of different diesel−methanol blends on the combustion and emission characteristics of diesel engines are investigated in terms of cylinder pressure, heat release rate, cylinder temperature, brake specific fuel consumption, thermal brake efficiency, brake power, and soot, nitrogen oxides, and carbon monoxide emissions in a four-stroke diesel engine. The corresponding three-dimensional Computational Fluid Dynamics (CFD) model was established using the Anstalt für Verbrennungskraftmaschinen List (AVL)-Fire coupled Chemkin program, and the chemical kinetic mechanism, including 135 reactions and 77 species, was established. The simulation model was verified by the experiment at 50% and 100% loads, and the combustion processes of pure diesel (D100) and diesel−methanol (D90M10, D80M20, and D70M30) were investigated, respectively. The results showed that the increase in methanol content in the blended fuel significantly improved the emission and power characteristics... [more]

Insights from the analysis of views towards energy sources are of paramount importance for the setting of successful energy policies, especially in instances where the public might be reluctant towards certain projects’ implementations. This work presents an analysis of social media comments data given in response to posts around the connection to the grid of a nuclear plant reactor in the United Arab Emirates (UAE). We assessed comments on Facebook posts of local and international media, as well those written in response to a post of a social media influencer. We extracted the main themes and performed sentiment analysis. The results indicate the presence of mixed views towards nuclear energy when focusing on comments on international media’s posts as well as on the social media influencer’s post considered, whilst they were very positive when assessing comments to local media. All in all, nuclear waste and previous nuclear accidents appear to be as the top of the mind; at the same ti... [more]

The use of nanofluids for heat transfer has been examined in recent years as a potential method for augmentation of heat transfer in different systems. Often, the use of nanoparticles in a working fluid does not disrupt the system in significant ways. As a result of this general improvement of a system’s heat transfer capabilities with relatively few detrimental factors, nanofluids and hybrid nanofluids have become an area of considerable research interest. One subcategory of this research area that has been under consideration is the concentration of each of the nanoparticles, leading to either successful augmentation or hindrance. The focus of the current experimental investigation was to examine the resulting impact on heat transfer performance as a result of each nanofluid implemented in an identical three-channel heat exchanger. This work examined the experimental impacts of 0.5 wt% titania (TiO2), 1 wt% titania, a mixture of 0.5 wt% titania and 0.5% silica, and a 0.5 wt% hybrid n... [more]

Ammonia and phosphate, which are present in large quantities in waste streams such as livestock manure, are key compounds in fertilization activities. Their recovery will help close natural cycles and take a step forward in the framework of a circular economy. In this work, a lab-scale three-chambered microbial electrolysis cell (MEC) has been operated in continuous mode for the recovery of ammonia and phosphate from digested pig slurry in order to obtain a nutrient concentrated solution as a potential source of fertilizer (struvite). The maximum average removal efficiencies for ammonium and phosphate were 20% ± 4% and 36% ± 10%, respectively. The pH of the recovered solution was below 7, avoiding salt precipitation in the reactor. According to Visual MINTEQ software modelling, an increase of pH value to 8 outside the reactor would be enough to recover most of the potential struvite (0.21 mmol L−1 d−1), while the addition of up to 0.2 mM of magnesium to the nutrient recovered solution... [more]