The pharmaceutical industry has been quite successful in developing new hydrogenation processes, and the chemistry of hydrogenation is currently well understood. However, it is a complex process to scale and optimize due to its high exothermicity, use of expensive catalysts and solvents, and its mass transfer requirements. Therefore, the aim of this work is to develop a CFD model to be able to describe the mass transfer, hydrodynamics, and mixing with respect to changes in rotational speed for a full-scale pharmaceutical hydrogenation reactor. In the first stage, a simple CFD model is used to predict the development of the surface vortex, and it is validated against literature data. In the second stage, the CFD model is tested on a full-scale configuration equipped with a Rushton turbine and a bottom kicker to study the formation of the surface vortex. Simulation results show the ability to predict the development of the surface vortex. These results are used to estimate the liquid hei... [more]

In underground coal gasification (UCG), it is essential for UCG production to accurately control the temperature of the gas produced at the wellhead of the production well and correctly calculate the variation law of the temperature field in the whole wellbore. UCG wellbore structures use three wellbore sprayed water cooling schemes. These schemes consider the heat exchange mechanism between the wellbore and the formation, the division of the production wellbore into the spray chamber section and the non-spray section, and the established temperature field model of the whole wellbore. The research shows that, due to the large temperature gradient formed in the wellbore heat transfer route under the spray tubing water injection cooling scheme, the temperature of the produced gas drops the most. The annular water injection cooling scheme can protect the cement sheath to a certain extent and is easier to implement; therefore, it is more suitable to use this scheme to cool the production w... [more]

In an effort to overcome the difficulty of real-time early warning via traditional infrared imaging technology caused by the complex working environment in coal mines, this paper proposes a mine early warning method based on uncooled infrared focal plane technology. The infrared thermal spectrogram of the detected object was visually displayed in a pseudo-color image with high resolution and high sensitivity, which can realize the real-time detection and early warning of personnel safety in modern mines. The multipoint compression correction algorithm based on human visual characteristics divided the response units of all acquisition units into gray intervals according to a threshold value, then the corresponding parameters were set in different intervals, and finally, each interval was compressed using a two-point correction algorithm. The volume of stored data was the sum of the calibration curve and the data from an encode table corrected by a MATLAB simulation, and the number of CP... [more]

How to reduce the friction resistance between two planes is a difficult problem that has been studied in the field of tribology. Aiming at this problem, the concept of reducing the friction resistance by exciting the periodic change of normal force between the planes is proposed. A calculation model of the displacement amplitude distribution of the plate is established based on the principle of reciprocity of work, and the influence of the periodic change of normal force on sliding friction between the planes is studied. Additionally, an experimental device for analysis of friction between the planes under the periodic change of normal force is established. The calculation model of the plate’s displacement amplitude distribution considering the change frequency of normal force is verified and modified by experiments. The research results mainly show two aspects. On the one hand, the calculation model of the displacement amplitude distribution of the plate is in good agreement with the... [more]

In the context of global efforts to pursue carbon neutrality, the research on the application technology of methanol fuel in internal combustion engines has ushered in a new peak. In order to provide a theoretical basis for the development of direct injection methanol engines, the spray characteristics of methanol with high-pressure direct injection were studied. Based on the visualization experimental device of constant volume vessels, the diffused background-illumination extinction imaging (DBI) and schlieren methods were applied to examine the distinctions in the evaporating spray properties between methanol and diesel under different injection pressures and ambient temperature conditions. Furthermore, aiming to maximize the potential of methanol fuel in compression ignition engines, under the premise that the alternative fuel can obtain the same total fuel energy as diesel, two different injection strategies of methanol were proposed and evaluated through the coordination of the no... [more]

When drilling to obtain hydrocarbons (oil and natural gas), we cannot underestimate the anomalously high pressures in the deposit layers, as these pressures can cause an uncontrollable eruption. Therefore, it is important to look for signs of anomalous high contour pressures over time, which, according to a detailed analysis, could be used to predict and quantify high formation pressures. These arise under conditions of intense vertical migration of formation fluids, where the liquids in the well have to carry part of the weight of overlying rocks and are often also related to tectonic activity. The main aim of the present study was to detect the emergence of a gas kick, which, as a result of an improper technological procedure, can cause an uncontrollable eruption, which can lead to a total accident of the well. In this article, we describe the use of modern drilling technology and sophisticated software that displays the current status inside the well. These can reveal impending pres... [more]

To improve the safety of electric vehicles, this paper analyzes the way of cooling lithium-ion batteries of electric vehicles and proposes an air-cooling scheme. First, a heat-generation model for the lithium-ion battery is prepared for numerical simulation and a finned air-cooling model is designed, which combines cold air with fins to lower the temperature of lithium-ion batteries. Through feasibility analysis, it is proved that the heat-generation model can reflect the actual heat generation of lithium-ion batteries. The cooling effect of the finned air-cooling model is also evaluated. The temperature can be 23.6 °C lower than the maximum compared with lithium-ion batteries without cooling. The cooling effect is desirable for diamond, triangle and rectangular lithium-ion battery packs, among which the rectangular battery pack achieves the most desirable effect. To conclude, to ensure the safe operation of lithium-ion batteries in electric vehicles, air cooling can be used to control... [more]

The oxidative coupling of methane (OCM) process is considered an intriguing route for the production of ethylene, one of the most demanded petrochemical products on the market. Ethylene can be produced by various methods, but the most widely used is the steam cracking process. However, due to the current instability of the crude oil market and the shale gas revolution, the production of olefins from natural gas has opened a new path for companies to mitigate the high demand for crude oil while utilizing an abundant amount of natural gas. In this work, the OCM process was compared with other existing processes, and the process was simulated using Aspen HYSYS. The flowsheet was divided into four sections, namely (i) the reaction section, (ii) the water removal section, (iii) the carbon dioxide capture section, and (iv) the ethylene purification section. Each section was thoroughly discussed, and the heat integration of the process was performed to ensure maximum energy utilization. The h... [more]

We report the upper and lower bounds for the levelized cost of high-temperature industrial process heat, supplied from electricity generated with solar-photovoltaic (PV) and wind turbines in combination with either thermal or electric battery storage using hourly typical meteorological year (TMY) data, in systems sized to supply between 80% and 100% of continuous thermal demand at a site in the northern part of Western Australia. The system is chosen to supply high-temperature air as the heat transfer media at temperatures of 1000 °C, which is a typical temperature for an alumina or a lime calcination plant. A simplified model of the electrical energy plant has been developed using performance characteristics of real PV and wind systems and TMY data of renewable energy resources. This was used to simulate a large sample of possible system configurations and find the optimal combination of the renewable resources and storage systems, sized to provide renewable shares (RES) of between 80... [more]

The development of modern energy is moving towards distributed generation, in which numerous sources of different capacities are connected into a single network. This makes it possible to increase the reliability of the entire system, since the probability of the failure of several energy sources at the same time is small. One of the major possibilities of distributed generation is the generation of electric energy based on high-speed gas turbines. The main advantage of these sources are high specific energy indicators, which improve with increasing rotation speed. However, it is technically difficult to realize the advantages of high-speed devices. It is necessary to abandon the step-down gearbox for the generator and directly connect it to a high-speed turbine, use high-strength materials that can withstand the load from centrifugal forces, abandon traditional plain bearings, and use special supports. Installations with generators that have a radial rotor design are the most widespre... [more]

In order to improve the pump device efficiency of the frequent operating condition of the extra-low head pumping station, the energy performance of the front-positioned shaft tubular pump device at two guide vane inlet angles has been researched. Based on the function of the guide vane in the pump device, the guide vane blades are divided into three parts: the inlet section, the middle section, and the outlet section. Combining numerical simulation and model tests, the energy performance of the pump device with the inlet section angle adjusted to 0° and −12° were studied and compared, respectively. The research results indicate that the inlet section angle of the guide vane has a significant effect on the energy performance of the pump device. When the guide vane inlet section is adjusted clockwise, the pump device efficiency of the optimal operating point—while the efficiency of the pump device at a low head and large discharge that deviate from the optimal operating point—will be imp... [more]

To obtain local flow velocity and holdup for oil−water in a near-horizontal well, array probes were adopted in the cross section of the wellbore. In this study, a fluid flow imaging logging tool called the single-probe multi-position measurement fluid imager (SPFI) was developed, which consisted of only a single turbine flowmeter and a single capacitance holdup probe. Most importantly, it could collect local velocity and holdup information at different locations along the vertical direction of the wellbore diameter. Firstly, in the large-diameter multi-phase flow simulation test loop, the instrument was placed at five different positions along the wellbore cross section to perform simulated measurements in different wellbore deviation angles and oil−water flowrates. Secondly, the experiment data was analyzed, and the experiment flow pattern chart, instrument response coefficient, and rule of the instrument response were obtained. At the same time, the calculation methods of local holdu... [more]

The optimal selection of machine equipment can reduce the energy consumption and processing time of the parts processing process in enterprises. The energy consumption and time of using different equipment to process the same product vary greatly. Traditional equipment selection is only through qualitative analysis comparing the process characteristics of using different equipment or optimizing parameters for a single piece of equipment. It does not take into account the dynamics of the production process and does not consider the impact of process factors on production decisions. To solve this problem, we established a production equipment selection model based on the business compass model and proposed a calculation method that considered energy consumption and time objectives in the production process. Quantitative analysis can be performed for different equipment. The energy consumption and processing time of different equipment are calculated by the beetle antennae search (BAS) al... [more]

The ever-worsening environmental situation brought on by the huge use of fossil fuels has ramped up biodiesel production. Several studies have shown that a 20% biodiesel-diesel blend (B20) could be the best for utility in a compression ignition (CI) engine. The present study focuses on the characteristics of a variable compression ratio (VCR) engine running with a B20 blend of sea mango biodiesel at compression ratios of 16:1, 17:1 and 18:1. VCR is a technology which permits the engine to modify its compression ratio to improve the fuel economy under varying loads. The experimental results reveal an improvement of 5.27% and 6.25% in the BTE as well as SFC with B20 mix, respectively, at compression ratio (CR) 18:1 against diesel at standard CR, which is 17:1. At CR 18:1, the CO, HC and smoke emissions of B20 fuel at full load were 26.78%, 37.76% and 23.44%, correspondingly lower than those of diesel at standard CR. However, the blend was found to have higher NOx emissions at all the CRs... [more]

Gas−liquid separation at natural gas wellheads has always been a key technical problem in the fields of natural gas transportation and storage. Developing a gas−liquid separation device that is both universal and highly efficient is the current challenge. A new type of combined gas−liquid separation device was designed in this study, and the efficiency of the separator was studied using a laser Doppler anemometer and phase Doppler particle analyzer at a flow rate of 10−60 Nm3/h. The results showed that the separation efficiency of the combined separator was above 95% at each experimental flow rate, verifying the strong applicability of the combined separator. Moreover, the separation efficiency was as high as 99% at the flow rates of 10 and 60 Nm3/h, thereby realizing efficient separation. This study is significant to the development of gas−liquid separation devices.

Plastics are widely used and are part of modern life. Recycling of plastic waste can be achieved by pyrolysis. Conventional pyrolysis of plastic waste takes place at temperatures higher than 450 °C, because the oil yield is higher. In this study, we examined if an initiator for radical reactions can achieve the conventional pyrolysis of HDPE and PP even at low temperatures. To support the onset of decomposition of HDPE and PP at low temperatures, 2-ethylhexyl nitrate (2-EHN) was added. 2-EHN forms radicals already at about 150 °C and can thus initiate the pyrolysis process at lower temperatures. Pyrolysis oil yields increased, especially for HDPE pyrolysis, at the expense of the gaseous (minus 50%) and especially the solid fraction (minus 80%). For PP and HDPE pyrolysis oil, the proportion of carbon compounds shifted toward shorter-chain, less cyclic compounds, and there was an improvement in the physicochemical property profile: the heating values of both oils were slightly higher and... [more]

This paper introduces the theoretical basis and optimization method of diesel engine working process theory. By comparing two Miller cycle schemes of B20 biodiesel under different load conditions of 1000 rpm (100%, 75%, and 50%), the best Miller cycle scheme and the best Miller degree were found. Then, based on the Miller cycle scheme, its performance was optimized and analyzed, and the best intake timing scheme of the B20 biodiesel engine under different working conditions was obtained. The results show that the performance of B20 biodiesel in variable valve overlap angle Miller cycle is better than that in variable cam profile Miller cycle, and the effect is the best when the Miller degree is 30 °CA. When B20 biodiesel is used under 100% and 50% load conditions, the maximum power under the two loads is in the area near intake valve timing 179 °CAA and exhaust valve timing 174 °CAA, and intake valve timing 224.5 °CAA and exhaust valve timing 119 °CAA, respectively. Fuel consumption, s... [more]

Fuel cell electric vehicles are expanding quickly from light-duty to heavy-duty applications such as buses or trucks. Hydrogen fuel quality needs to comply with ISO14687:2019 to avoid any improper performance of the vehicles. Total sulphur is one of the most impactful contaminants to a fuel cell system and has a threshold of 4 nmol/mol. Most analytical methods provide a limit of detection (LOD) of 1 nmol/mol for total sulphur in hydrogen. Total sulphur is often not quantified and reported as below LOD due to lack of sensitivity. A new analytical method using cryo-focussing gas chromatography with sulphur chemiluminescence detector (cryo-GC-SCD) was developed for picomol/mol analysis of total sulphur. The method achieved linearity between 150−16,000 picomol/mol, validated against NPL reference materials, and relative expanded uncertainty of 21% (k = 2). Samples from 11 hydrogen refuelling stations (HRS) were analysed using this method. The total sulphur amount fraction for all the HRSs... [more]

Sustainable energy systems are an essential response to climate change challenges [...]

Brittleness is an essential parameter to determine the deformation and failure behavior of rocks, and it is useful to quantify the brittleness of rocks in numerus engineering practices. A novel energy-based brittleness evaluation index is proposed in this study, which redefines the dissipated proportion of ultimate elastic strain energy relative to post-peak failure energy and residual elastic strain energy. A series of conventional triaxial compression (CTC) tests were performed on shale rock to verify the reliability and accuracy of the brittleness index. The results show that the proposed index can precisely reflect the deformation and failure characteristic of rocks under different confining pressures. Based on the testing data from six types of rocks in previous studies, the universality of the novel index was verified. According to comparison with existing brittleness indices, the new brittleness index can more precisely characterize the brittleness of rock.

The spray drying technique is suitable for different kinds of liquid dispersions and can be easily optimized to produce solid particles with tailored properties. The spray drying technique is a complex process. As an example, it is difficult to track drying kinetics, shape, and morphological changes on the scale of a single droplet. To better understand the effect of drying process variables on dried particle formation, it is useful to observe the drying of single droplets. Fundamental processes, such as mass and heat transfer, can then be easily monitored and compared with theoretical models. Acoustic levitation enables droplet/particle suspension in the air without any mechanical contact. Experiments in the acoustic levitator can be used to mimic the drying process in the spray dryer. The drying kinetics of single droplets of PEG6000 into solid particles was studied. Droplets with an initial polymer concentration (PEG6000 aqueous solution of 5%, 10%, and 15% (w/w)) were investigated... [more]

Liquefied natural gas (LNG), as cleaner transitional energy than coal, is becoming increasingly prominent in the energy structure of various countries based on their low-carbon background, and its demand has grown rapidly worldwide. Storage tanks are the most commonly used LNG storage facilities. Owing to a variety of internal composition and external environmental factors, the instability phenomenon of LNG in the tanks may occur during storage, leading to potential safety risks. An in-depth understanding of the stratification and rollover behavior of LNG is therefore required to ensure and promote efficient utilization and stable storage of LNG. This paper provides a comprehensive review of the current state of LNG stratification and rollover behavior. The factors for causing LNG stratification and rollover behavior in the storage tanks are summarized, methods for characterizing stratification and rollover behavior are discussed, and measures for inhibiting the instability phenomenon... [more]

In this work, the influence of KCl concentration on the gasification characteristics of lignite coal char between 800−1100 °C is studied through the experiments of temperature programmed gasification and isothermal gasification using a thermogravimetric analyzer. The gasification kinetics, characteristic parameters, and the reaction mechanism of catalytic gasification is explored using the random pore model (RPM). In view of temperature programmed gasification, the gasification rate of coal char is relatively slow when the temperature is below 700 °C, and only when the temperature is higher than 700 °C, the gasification starts to accelerate. Results show that with the existence of a catalyst, the temperature required for gasification reaction is reduced and the gasification reaction rate is increased. Furthermore, the higher concentration of KCl leads to the shorter half reaction time, the higher gasification rate, and the stronger catalysis. In addition, the activation energy of AW-ch... [more]

The demand for natural products is steadily increasing, and pharmacotechnological engineering is needed to allow rigorous investigation of their efficacy and safety in clinical conditions representing still unmet needs. Among aged patients affected by dementia, up to 80% of residents in nursing homes suffer from chronic pain and 97% from fluctuant neuropsychiatric symptoms (NPS), of which the most challenging is agitation. It is, at least in part, due to undertreated pain and treated with antipsychotics almost doubling the risk of death. In the frame of a scoping review assessing the existence of essential oils undergoing engineering pharmacotechnological processes using solid lipid nanoparticle delivery systems for clinical translation in pain and/or neuropsychiatric symptoms of dementia following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR), here we identified that the sole essential oil engineered to overcome the c... [more]

Voltage sags are a serious problem within power supplies, which pose threats to both residential electricity and industrial manufacturing. Since any one sag may be recorded by multiple monitoring devices from different substations, the issue of redundant information in data arises. In this regard, a novel method for voltage sag events based on projection technology, shape dynamic time warping (shapeDTW), and spectral clustering is proposed. The main contributions of this paper may be summarized as follows: (1) We present a new method for extracting the voltage anomaly waveform, which is a fast projection segmentation algorithm (FPSA). The voltage sag waveform is only a part of the voltage anomaly waveform, so the voltage anomaly waveform contains more information. (2) ShapeDTW and spectral clustering are used to match and cluster voltage anomaly waveforms, so as to achieve the normalization of voltage sag events. (3) In practical engineering, the proposed method in the paper can be use... [more]