The aquathermolysis process is widely considered to be one of the most promising approaches of in-situ upgrading of heavy oil. It is well known that introduction of metal ions speeds up the aquathermolysis reactions. There are several types of catalysts such as dispersed (heterogeneous), water-soluble and oil soluble catalysts, among which oil-soluble catalysts are attracting considerable interest in terms of efficiency and industrial scale implementation. However, the rock minerals of reservoir rocks behave like catalysts; their influence is small in contrast to the introduced metal ions. It is believed that catalytic aquathermolysis process initiates with the destruction of C-S bonds, which are very heat-sensitive and behave like a trigger for the following reactions such as ring opening, hydrogenation, reforming, water−gas shift and desulfurization reactions. Hence, the asphaltenes are hydrocracked and the viscosity of heavy oil is reduced significantly. Application of different hyd... [more]

Using biodiesel in diesel engines is beneficial for reducing emissions of carbon monoxide (CO), hydrocarbons (HC) and particulate matters (PM). Biodiesel is usually produced from vegetable oils or animal fats. When produced from plant oil or woody plant sources, biodiesel can reduce a significant amount of carbon dioxide on a life cycle basis. The objective of this study is to produce biodiesel from a non-conventional woody plant source that is, crude tall oil, which is a dark brown viscous liquid extracted and processed in wood pulping plants. It contains a high percentage of fatty acids. From raw crude tall oil, tall oil fatty acids were separated and were successfully used for the production of biodiesel in this study. Although biodiesel produces lower CO, HC and PM than petroleum diesel fuel, it produces higher oxides of nitrogen (NOx) emissions in diesel engines. Water emulsifications of diesel-biodiesel blends are investigated in a direct injection (DI) diesel engine in this work... [more]

Thermal energy storage systems help to couple thermal energy generation and process demand in cogeneration facilities. One single deposit with two design temperatures and one main temperature step in sensible thermal energy storage define the thermocline systems. Performance of one high size real thermocline thermal energy storage system is analysed. Starting from temperature and mass flow rate data registered by the plant control system, one advanced thermodynamic analysis is performed. The quality of heat storage is analysed in terms of evaluation of the stratification in the thermocline zone. The temperature data registered at 21 positions is extended by displacement analysis generating detailed profiles. Fraction of recoverable heat, thermocline width, stratification indices based on energy and exergy analysis, and mean temperature gradients in the thermocline region are calculated. These parameters are monitored under real operation conditions of the plant. The calculated paramete... [more]

In order to improve the accuracy of numerical simulation, a new heat transfer model is developed by using a modular approach in the Anstalt für Verbrennungskraftmaschinen (AVL)-Boost software. The improved heat transfer model mainly considers the effects of the swirl and boiling heat transfer inside the engine. In addition, a chemical kinetics mechanism including 475 reactions and 134 species is employed to predict the combustion of diesel engines fueled with biodiesel. The result shows that the boiling heat transfer will occur, especially in the high-temperature area. Analysis shows that the improved model is reliable and its precision is increased. Finally, the perturbation method is employed to investigate the relatively important inputs as the complex nonlinear function with a lot of output data and input data produced by the improved model. The relative effects of different parameters such as EGR, injection mass, injection timing, compression ratio, inlet air pressure, fuel inject... [more]

This article introduces a novel laboratory-scale process for the electrochemical synthesis of hydrogen peroxide (H2O2). The process aims at an energy-efficient, decentralized production, and a mathematical optimization of it is presented. A dynamic, zero-dimensional mathematical model of the reactor is set up in Aspen custom modeler®. The proposed model constitutes a reasonable compromise between complexity and convergence. After thoroughly determining the reaction kinetics by adjustment to experimental data, the reactor unit is embedded in an Aspen Plus® flowsheet in order to investigate its interaction with other unit operations. The downstream contains another custom module for membrane distillation. Electricity appears as a resource in the process, and optimization shows that it reaches product purities of up to 3 wt.-%. Both the process optimization and the adjustment of the reaction kinetics are treated as multi-criteria optimization (MCO) problems.

An absorption air-conditioning system is a good choice for green buildings. It has the superiority in the utilization of renewable energy and the refrigerant is environment-friendly. However, the performance of the traditional absorption system has been restricted by the energy waste in the thermal regeneration process. Capacitive deionization (CDI) regeneration is proposed as a potential method to improve system efficiency. In the new method-based air-conditioning system, strong absorbent solutions and pure water are acquired with the joint work of two CDI units. Nevertheless, the practical CDI device is composed of a lot of CDI units, which is quite different from the theoretical model. To reveal the performance of multiple CDI units, the model of the double/multi-stage CDI system has been developed. Analysis has been made to expose the influence of some key parameters. The results show the double-stage system has better performance than the single-stage system under certain conditio... [more]

This study aimed to improve the adsorption capacity of activated carbon (AC) towards naphthalene (NAP) in aqueous solutions. Starch-based AC (SAC) and pulverized coal-based AC (PCAC) were prepared in a one-pot procedure by activation with oleic acid and KOH under microwave heating. Brunauer−Emmett−Teller (BET) specific surface areas reached 725.0 and 912.9 m2/g for in situ modified SAC (O-SAC1) and PCAC (O-PCAC1), respectively. π−π bond, H-bond, and hydrophobic effects were directly involved in the NAP adsorption process. Batch adsorption data were well fitted by pseudo-second order kinetics and the Freundlich isotherm model. As compared to ACs prepared with only KOH activation, NAP adsorption capacities of PCAC and SAC prepared by the one-pot method increased by 16.9% and 13.7%, respectively. Influences of varying factors were investigated in column adsorption of NAP using O-SAC1 and O-PCAC1. Based on breakthrough curves analysis, the larger column height (H), lower flow rate (Q0), an... [more]

A critical review on the synthesis, characterization, and modeling of polymer grafting is presented. Although the motivation stemmed from grafting synthetic polymers onto lignocellulosic biopolymers, a comprehensive overview is also provided on the chemical grafting, characterization, and processing of grafted materials of different types, including synthetic backbones. Although polymer grafting has been studied for many decades—and so has the modeling of polymer branching and crosslinking for that matter, thereby reaching a good level of understanding in order to describe existing branching/crosslinking systems—polymer grafting has remained behind in modeling efforts. Areas of opportunity for further study are suggested within this review.

The aim of this study was to investigate the influence of biomass micronization on energy production using a converted aircraft turbine AI-20. The test system was constructed in such a way to ensure continuous operation for a given period of time and was equipped in a chopper, a flail mill, and a micronizer. The turbine had the ability to produce energy from solid biomass and as well conventional fuels. The most energy was obtained from absolutely dry sunflower husk (17.27 MJ/kg) and the least from Poplar (7.82 MJ/kg). Miscanthus, wheat straw, and hay (approximately 17 MJ/kg) showed high values of energy production. In addition, the thermal decomposition of wheat straw at 350 and 450 °C was studied using the Py-GC/MS technique in a helium atmosphere to determine the gaseous compounds formed during biomass gasification under anaerobic conditions. The results obtained indicate the formation of compounds classified as phenols (vanillin, hydroxymethylfurfural).

More than 1.2 billion kW wind and solar power generation will be integrated in China by 2030. The new provincial renewable portfolio standard, officially implemented in 2020, establishes an efficient bridge between rapid capacity growth and limited accommodation capability. A data-driven prospect analysis framework was proposed to evaluate the activated potential under two kinds of nearby accommodation approaches and to explore the completion prospect of this new obligated quota from provincial levels. Empirical results illustrate diverse prospects across regions. Particularly, it is hard for two kinds of provinces to complete their obligated quotas merely via the single nearby accommodation approach: The first one is close to renewable energy resources but lacks flexible peak regulation capability in Northeast and Northwest China, and the other is close to the nationwide load center but lacks nearby integration from renewables in Southeast, North, and Middle China. Therefore, the path... [more]

Enzymatic biodiesel production has attracted tremendous interest due to its well-recognized advantages. However, high enzyme costs limit the application of enzymatic processes in industrial production. In the past decade, great improvements have been achieved in the lab and the industrial scale, and the production cost of the enzymatic process has been reduced significantly, which has led to it being economically competitive compared to the chemical process. This paper summarizes the progress achieved in enzymatic biodiesel research and commercialization, including reducing enzyme cost, expanding low-quality raw materials, and novel reactor designs. The advantages and disadvantages of different enzymatic processes are also compared.

The solubility in triple water-salt systems containing NdCl3, PrCl3, YCl3, TbCl3 chlorides, and water-soluble fullerenol C60(OH)24 at 25 °C was studied by isothermal saturation in ampoules. The analysis for the content of rare earth elements was carried out by atomic absorption spectroscopy, for the content of fullerenol—by electronic spectrophotometry. The solubility diagrams in all four ternary systems are simple eutonic, both consisting of two branches, corresponding to the crystallization of fullerenol crystal-hydrate and rare earth chloride crystal-hydrates, and containing one nonvariant point corresponding to the saturation of both solid phases. On the long branches of C60(OH)24*18H2O crystallization, a C60(OH)24 decreases by more than 2 orders of magnitude compared to the solubility of fullerenol in pure water (salting-out effect). On very short branches of crystallization of NdCl3*6H2O, PrCl3*7H2O, YCl3*6H2O, and TbCl3*6H2O, the salting-in effect is clearly observed, and the so... [more]

Gasification is a promising technology for the conversion of mixed solid waste like refuse-derived fuel (RDF) and municipal solid waste (MSW) into a valuable gas consisting of H2, CO, CH4 and CO2. This work aims to identify the basic challenges of a single-stage batch gasification system related to tar and wax content in the producer gas. RDF was first gasified in a simple semi-batch laboratory-scale gasification reactor. A significant yield of tars and waxes was received in the produced gas. Waxes were analyzed using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectrometry. These analyses indicated the presence of polyethylene and polypropylene chains. The maximum content of H2 and CO was measured 500 sec after the start of the process. In a second series of experiments, a secondary catalytic stage with an Ni-doped clay catalyst was installed. In the two-stage catalytic process, no waxes were captured in isopropanol and the total tar content decre... [more]

Energy generation and its utilization is bound to increase in the following years resulting in accelerating depletion of fossil fuels, and consequently, undeniable damages to our environment. Over the past decade, despite significant efforts in renewable energy realization and developments for electricity generation, carbon dioxide emissions have been increasing rapidly. This is due to the fact that there is a need to go beyond the power sector and target energy generation in an integrated manner. In this regard, energy systems integration is a concept that looks into how different energy systems, or forms, can connect together in order to provide value for consumers and producers. Cogeneration and trigeneration are the two most well established technologies that are capable of producing two or three different forms of energy simultaneously within a single system. Integrated energy systems make for a very strong proposition since it results in energy saving, fuel diversification, and s... [more]

An indirect evaporative cooling system combining with thermoelectric cooling technology (i.e., TIEC system) is proposed, in which a counter-flow plate-fin indirect evaporative cooler is inserted with thermoelectric cooling (i.e., TEC) modules. In hot and humid climate, condensation may occur on the dry channel surface of the cooler. For the TIEC system, with the aid of TEC technology, the surface temperature of the dry channel can be much lower than that of a traditional indirect evaporative cooler, thus, the condensation from the primary air is more likely to take place. A numerical model of this novel TIEC system is developed with specifically taking condensation from primary air into account. Detailed performance analysis of the TIEC system is carried out. Analytical results found that the condensation from primary air reduces the dew point effectiveness by up to 45.0% by weakening the sensible heat transfer but increases the coefficient of performance by up to 62.2% by increasing t... [more]

Industrial hydraulic turbines, a kind of small-scaled turbine in a more compact and flexible application, are frequently used in hydrogen cracking, synthesis ammonia, and circulating water field. Besides the energy recovery efficiency, the working stability at variable speed situations is a critical issue, since its rotation speed changes with the flow parameters of the upstream. In this paper, a conventional turbine was numerically investigated under three different rotation speeds and its best efficiency points (BEPs). The velocity profiles, blade load, pressure fluctuation, and vibration features were discussed to form a comprehensive evaluation of turbine stability. The numerical results were validated through turbine external characteristic and vibration tests. The results indicate that the pressure pulsation and vibrations increase when it deviates from the rated rotation speed, but the relatively low flowrate point behaves better than the large point in the aspect of turbine sta... [more]

-Octanol, as an oxygenated fuel, is considered as one of the most promising alternative fuels, owing to advantages such as its low hygroscopic nature, high cetane number, and high energy content. However, the introduction of n-octanol leads to a higher viscosity and latent heat of evaporation (LHOE), affecting the combustion and emission performances of compression ignition (CI) engines. This study sheds light on the effect of injection pressures (IPs, ranging from 60 to 160 MPa) on the combustion and emission performances of a turbocharged CI engine, in conjunction with n-octanol/diesel blends. According to the proportion of oxygen content, the test fuels contain pure diesel (N0), N2.5 (2.5% oxygen content in the blending fuels), and N5 (5% oxygen content in the blending fuels). The results indicate that the blending fuels have little influence on the in-cylinder pressure, ignition delay (ID), and CA50, but they improve the brake thermal efficiency (BTE). In terms of emissions, with t... [more]

This Special Issue on “Process Modeling in Pyrometallurgical Engineering” consists of 39 articles, including two review papers, and covers a wide range of topics related to process development and analysis based on modeling in ironmaking, steelmaking, flash smelting, casting, rolling operations, etc [...]

Biochar, which is a byproduct of gasification, is used in a wide range of fields such as water filtration, agriculture, and electronics, to name a few. The metals in the biomass were thought to end up either in the ash or distributed throughout the biochar. In this study, the goal was a more thorough characterization of biochar resulting from a single-stage downdraft gasifier. One of the first observations was that some metals actually localize into small (~25 micron diameter) metallic nodules on the biochar surface. Further analysis included ultimate and proximate analysis, Brunauer−Emmert−Teller (BET) analysis, and scanning electron microscopy X-ray spectroscopy (SEM-EDS). Biomass fuel included corn grains, soybeans, and wood pellets, with wood biochar showing the highest fixed carbon content, at 91%, and the highest surface area, at 92.4 m2/g. The SEM analysis showed that certain minerals, including potassium, phosphorus, calcium, iron, nickel, silicon, and copper, formed nodules wi... [more]

Expectation for renewable energy is increasing due to environmental pollution such as fossil fuel depletion, CO2 emission, and harmful gases. Therefore, in this study, extracted sugars of microalgae, which cause algal blooms and crude glycerol, a biodiesel industry byproduct, were used simultaneously to produce 2,3-BDO. The 2,3-BDO production using only extracted algal sugars was about 4.8 g/L at 18 h, and the production of 2,3-BDO using both extracted algal sugar and crude glycerol was about 7 g/L at 18 h. It was confirmed that the main culture with crude glycerol was increased 1.5-fold compared to the case of using only extracted algal sugars. In addition, four components of the main medium (ammonium sulfate, casein hydrolysate, yeast extract, and crude glycerol) were statistically optimized and the concentrations of the medium were 12, 16, 12, and 13 g/L, respectively. In addition, the final 2,3-BDO production was about 11g/L, which 1.6-fold higher than before the optimization proce... [more]

This paper presents a part of the study referring to exploring Energy Recovery from Municipal Solid Waste in Maramures County. In order to analyze the possibility of energetic recovery of municipal solid waste (MSW), data referring to the management system of MSW from Maramures county were cumulated and processed in a first stage in order to estimate the quantity of municipal solid waste and its composition, which might be recovered energetically. In the next stage, samples of municipal solid waste were collected from landfills, which were submitted to specific processing and analyses. The experimental data were processed and in the end the energy potential of municipal solid waste from Maramures county was found. This study will help stakeholders and those involved in waste management to assess the possibility of energy recovery. The analysis of the study concluded that municipal solid waste in Maramures County is a potential source of renewable energy.

Algorithms that compute locally optimal continuous designs often rely on a finite design space or on the repeated solution of difficult non-linear programs. Both approaches require extensive evaluations of the Jacobian Df of the underlying model. These evaluations are a heavy computational burden. Based on the Kiefer-Wolfowitz Equivalence Theorem, we present a novel design of experiments algorithm that computes optimal designs in a continuous design space. For this iterative algorithm, we combine an adaptive Bayes-like sampling scheme with Gaussian process regression to approximate the directional derivative of the design criterion. The approximation allows us to adaptively select new design points on which to evaluate the model. The adaptive selection of the algorithm requires significantly less evaluations of Df and reduces the runtime of the computations. We show the viability of the new algorithm on two examples from chemical engineering.

The startup process occurs frequently for pumped storage units. During this process, the rotating rate that changes rapidly and unsteady flow in runner cause the complex dynamic response of runner, sometimes even resonance. The sharp rise of stress and the large-amplitude dynamic stresses of runner will greatly shorten the fatigue life. Thus, the study of start-up process in turbine mode is critical to the safety operation. This paper introduced a method of coupling one dimensional (1D) pipeline calculation and three-dimensional computational dynamics (3D CFD) simulation to analyze transient unsteady flow in units and to obtain more accurate and reliable dynamic stresses results during start up process. According to the results, stress of the ring near fixed support increased quickly as rotating rate rose and became larger than at fillets of leading edge and band in the later stages of start-up. In addition, it was found that dynamic response can be caused by rotor stator interaction (... [more]

This article aims to develop a proton exchange membrane (PEM) electrolyzer emulator. This emulator is realized through an equivalent electrical scheme. It allows taking into consideration the dynamic operation of PEM electrolyzers, which is generally neglected in the literature. PEM electrolyzer dynamics are reproduced by the use of supercapacitors, due to the high value of the equivalent double-layer capacitance value. Steady-state and dynamics operations are investigated in this work. The design criteria are addressed. The PEM electrolyzer emulator is validated by using a 400-W commercial PEM electrolyzer. This emulator is conceived to test new DC-DC converters to supply the PEM ELs and their control as well, avoiding the risk to damage a real electrolyzer for experiment purposes. The proposed approach is valid both for a single cell and for the whole stack emulation.

Propylene glycol, also known as 1,2 propanediol, is one of the most important chemicals in the industry. It is a water-soluble liquid, considered by the U.S. Food and Drug Administration as safe to manufacture consumer products, including foodstuffs, medicines, and cosmetics. This chemical has essential properties, such as solvent, moisturizer, or antifreeze, in addition to a low level of toxicity. This paper aims to present the selection, simulation, and dimensioning of a trickle bed reactor at a laboratory scale. The sizing was validated with other authors. Two predictive models have been considered for reactor modeling, intrinsic kinetics and coupled intrinsic kinetics, along with mass transfer equations and the wetting of the catalyst particles. The model was implemented using Aspen Custom Modeler® (20 Crosby Dr. Bedford, MA 01730, EE. UU.) to study the reactor behavior in terms of conversion. The results show the profiles of different variables throughout the reactor and present h... [more]