Thermal Extraction Research Articles

Investigation on the mechanism of solvothermal extraction of coals by macromolecular models

In this study, solvothermal extraction of two coals (Fangezhuang fat coal, FGZ; Sima lean coal, SM) were conducted by N-methylpyrrolidone (NMP); the molecular models of corresponding hypercoals (HPC) were firstly constructed besides that of coals to clarify the extractions mechanism, aiming to provide a technically feasible route to investigate the mechanism of other extraction processes. The structural parameters were obtained by means of proximate analysis, ultimate analysis, carbon-13 nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy and Fourier Transform infrared spectroscopy. The results showed that aromatic ring types of both raw coals were mainly naphthalene and anthracene, nitrogen atoms existed in pyrrole and pyridine whilst sulfur atoms in thiophene substantially, aliphatic carbons presented in the form of methyl and methylene groups while oxygen-containing functional groups mainly consisted of phenolic hydroxyl, carbonyl, carboxyl and a few ether bonds. Thus, the macromolecular structure models were constructed, with simulated molecular formulas were C168H136N2O12S, C135H74N2O12S, C166H136N2O6S and C128H82N2O11, respectively. After modifying the macromolecular models by Materials Studio for geometric optimization, annealing dynamics calculation, density simulation and analysis of chemical bonds, these four models reflected the macromolecular structural characteristics precisely. On the other hand, both models of raw coals changed significantly in functional groups, branched chain length and quantity pre and post thermal extraction, indicated that the thermal extraction process was mainly affected by swelling behavior and pyrolysis. This study provided new theoretical support in the development of coal extraction technology and understanding of HPC on the macromolecular level by a model basis.

Fracturing and thermal extraction optimization methods in enhanced geothermal systems

Fracturing and thermal extraction optimization methods in enhanced geothermal systems

Influence of Thermal Treatments, Extraction Methods, and Storage Conditions on Lycopene Content of Foods

Lycopene is one of the main carotenoids in our daily diet. Fruit variety, environmental conditions, and maturity stage are the factors affecting the content of lycopene. Various processing techniques and extraction methods may also affect the level of lycopene in different food products, consequently changing the biological role of lycopene. The biological role of lycopene is to defend the tissues of tomatoes (conjugate bonds) and attract predators (red colour). Moreover, storage conditions also impact the lycopene content of fruits, vegetables, and their products. Efficient and novel technological interventions are required for stabilizing lycopene content during postharvest procedures, such as refrigeration, heating, extraction, and transportation. Therefore, the study of different crucial factors concerning the change in lycopene content is required. The present review explores the lycopene content of different food commodities and the effect of postharvest operations and processing techniques on lycopene content. It also highlights the storage impact on the concentration of lycopene which may be useful for future studies.

Evaluation of cold extracted bioactive compounds from tomato pomace and its use in food fortification

ABSTRACT The purpose of this study was to find a method for the cold extraction of biologically active compounds from tomato pomace, as there are no acceptable, affordable and environmentally friendly extraction methods, and its ability to maintain their vital functions and properties. This method was then evaluated as compared to the traditional thermal extraction methods. The limits of traditional extraction techniques have been overcome by the advent of numerous non-thermal new extraction techniques over the past 20 years. Three methods were used to help extract these compounds, which are blending the frozen (BF), microwave-assisted (MA) and Ohmic heating (OH). The results showed that the BF method was the best extraction method, and the amount of lycopene 487.4 µg/g, β-carotene 115.8 µg/g, total phenolics 1297.4 µg GAE/g, total flavonoids 462.5 µg QE/g and antioxidant activity 89.1%. It was found that the most abundant phenolic compounds in tomato pomace were gallic acid and ellagic nacid, as it contains seven essential amino acids, and that glutamic acid was the dominant acid. Fatty acid estimation showed that linoleic cis and oleic cis were the dominant acids, as they were 585.50 and 164.67 µg/g total fatty acids, respectively. It also contained on unsaturated fatty acids 820.44 µg/g.

Numerical Assessment of the Inhomogeneous Temperature Field and the Quality of Heat Extraction of Nb3Sn Impregnated Magnets for the High Luminosity Upgrade of the LHC

The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN foresees the installation of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn-based quadrupole magnets at selected interaction points of the accelerator. The precise knowledge of each magnet's thermal characteristics and heat extraction performance in response to power depositions during both nominal and ultimate conditions is essential in determining safe operating margins. A 2D numerical framework has been developed to systematically assess the temperature distribution in the combined magnet structure-superfluid He system of each magnet and enveloping cold mass using open-source software. Here a full cross-section of a magnet cold mass is modelled, under the power density distribution expected at the most exposed longitudinal position during accelerator operation at an instantaneous luminosity of 5.0x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">34</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , corresponding to the nominal conditions for HL-LHC. Temperature maps and margins are presented for the inner triplet magnets (MQXF) for both horizontal and vertical beam crossing conditions, along with the validation of the design of cold mass cooling channels for heat extraction.

Anomalies in Infrared Outgoing Longwave Radiation Data before the Yangbi Ms6.4 and Luding Ms6.8 Earthquakes Based on Time Series Forecasting Models

Numerous scholars have used traditional thermal anomaly extraction methods and time series prediction models to study seismic anomalies based on longwave infrared radiation data. This paper selected bidirectional long short-term memory (BILSTM) as the research algorithm after analyzing and comparing the prediction performance of five time series prediction models. Based on the outgoing longwave radiation (OLR) data, the time series prediction model was used to predict the infrared longwave radiation values in the spatial area of 5° × 5° at the epicenter for 30 days before the earthquake. The confidence interval was used as the evaluation criterion to extract anomalies. The examples of earthquakes selected for study were the Yangbi Ms6.4-magnitude earthquake in Yunnan on 21 May 2021 and the Luding Ms6.8-magnitude earthquake in Sichuan on 5 September 2022. The results showed that the observed values of the Yangbi earthquake 15 to 16 days before the earthquake (5 May to 6 May) exceeded the prediction confidence interval over a wide area and to a large extent. This indicates a strong and concentrated OLR anomaly before the Yangbi earthquake. The observations at 27 days (9 August), 18 days (18 August), and 8 days (28 August) before the Luding earthquake exceeded the prediction confidence interval in a local area and by a large extent, indicating a strong and scattered OLR anomaly before the Luding earthquake. Overall, the method used in this paper extracts anomalies in both spatial and temporal dimensions and is an effective method for extracting infrared longwave radiation anomalies.

A novel combined metallurgy-beneficiation method for the facile and low-cost comprehensive resource utilization of low-grade kaolin solid wastes

Low-grade kaolin is the largest emissions of industrial solid waste that is difficult to dispose of and pollutes the environment seriously. From the perspective of harmless and complete resource utilization, we proposed a novel strategy that combines the wet leaching under mild conditions and physical beneficiation for the facile and low-cost high-valued utilization of low-grade kaolin that involves high-efficiency recovery of aluminum (Al), silicon (Si), and titanium (Ti). The key to successful implementation of this method lies in the new discovery that the residual SiO2 after Al extraction of kaolinite by acid leaching under specific conditions could be rapidly dissolved in dilute NaOH solution at room temperature 25 °C. This highly reactive SiO2 challenges the conventional notions of various silica species are usually chemically stable. By adjusting the key technical parameters of the thermal activation-acid leaching process, the selective and efficient extraction of Al2O3 from low-grade kaolin was realized. The acid leaching residue was then subjected to selective recovery of SiO2 by alkaline leaching at 25 °C to obtain high-quality sodium silicate. Finally, the alkali leaching residue as titanium coarse concentrate was separated by centrifugal concentrator to obtain artificial rutile (TiO2 >91.06%). The key mechanism for the formation of the highly reactive silica was also systematically studied and confirmed.

Mechanisms, Capabilities, Limitations, and Economic Stability Outlook for Extracting Phenolics from Agro-byproducts Using Emerging Thermal Extraction Technologies and Their Combinative Effects

Mechanisms, Capabilities, Limitations, and Economic Stability Outlook for Extracting Phenolics from Agro-byproducts Using Emerging Thermal Extraction Technologies and Their Combinative Effects

Structure optimization of helium-cooled blanket for fusion reactor based on three-dimensional full-scale thermal-hydraulic analysis

Fusion energy is widely considered as the most promising method to solve the energy crisis, while the blanket is of vital importance in the fusion device due to its main function of thermal extraction and energy conversion. The high heat flux from plasma and the internal nuclear heat deposition are imposed on fusion blanket. Slice model or two-dimensional model is usually adopted for traditional design of fusion blanket, in which most side effects are neglected, introducing relatively large uncertainty for thermal removal capability of the blanket. In this study, the integral three-dimensional full-scale model is established based on the split-zone method for mesh generation. Based on the validated numerical method, the preliminary thermal-hydraulic analysis of the full-scale model shows that inadequate heat transfer and significant flow distribution difference are encountered for the initial blanket design, in which the full-scale effect is not considered. After that, the specific structure modifications are proposed for different blanket components to solve the abovementioned problems. The maximum temperature of first wall is reduced from 671°C to 639°C, which is under the material temperature limit of 650°C; the inverse V-shaped flow distribution in the cap is modified as more even flow in cap channels; the maximum temperature of the function zone in blanket is reduced from 999°C to 759°C, which is an important structure modification for the blanket. The integral three-dimensional full-scale thermal-hydraulic analysis is performed after the local structure modification. The results show that the function zone is cooled down obviously by the coolant in the side wall. Compared to the temperature limit of 900°C for lithium orthosilicate, there is a more rigorous limit for the beryllium material, since they share the common cooling capability layer by layer while the temperature limit for the latter is only 650°C. The three-dimensional full-scale thermal-hydraulic analysis in our research is valuable to evaluate the integral reliability of the fusion blanket.

Sustainable utilisation and transformation of the thermal energy from coalfield fires: A comprehensive review

Coalfield fires provide high-temperature heat storage at relatively shallow depths, their overburden and upper strata contain immense amounts of thermal energy, which is identical to the reservoir condition of shallow geothermal energy. Therefore, heat waste resources produced by coalfield fires can be developed and utilised as low-medium grade geothermal resources. By comparing the available methods for thermal energy extraction and conversion, it was found that the heat transfer technology using two-phase closed thermosyphon and thermoelectric conversion using thermoelectric conversion device were the most suitable for use in coalfield fire areas. As a highly effective heat conduction scheme, the two-phase closed thermosyphon was proposed as a feasible means of thermal energy extraction. Meanwhile, thermoelectric conversion device was utilised to transform thermal energy directly into electrical energy to realise the reuse of the waste heat. Some influencing factors on the heat transfer properties of two-phase closed thermosyphon were analysed, and efficiency of the thermoelectric conversion device was investigated. The thermoelectric parameters for these thermoelectric materials of interest were evaluated, and several effective methods for the improvement of thermoelectric conversion efficiency were exposed. In addition, an enhanced thermoelectric conversion and utilisation system with increased conversion efficiency was proposed. The results presented in the current study can provide a theoretical basis and technical support information for the feasible management and adequate control of coalfield fires and utilisation of the resulting thermal energy.

Green approach for polyphenol extraction from waste tea biomass: Single and hybrid application of conventional and ultrasound-assisted extraction

Based on a green approach, the potential use of waste tea biomass (fiber and second sieving) with rich polyphenol content was investigated as an alternative source of polyphenol to achieve an economic added value. In addition, this study demonstrated a comparative approach to explore the most sustainable green extraction method by the assessment of single ultrasound-assisted extraction (UAE) at various frequencies (20, 35, and 200 kHz) and the hybrid operations of ultrasound (US) and thermal extraction (50 °C and 80 °C). As a result, it has been determined that waste tea biomass, with a polyphenol extraction rate of more than 80%, provides a higher recovery capacity than tea leaf (the highest polyphenol recovery rate of 72.5%) in almost all single operations. Among the single UAE, 20 kHz was expressed as the method succeeding with high recovery rates (84%) within 30 min for fiber waste. In contrast, the hybrid operation consisting of 20 kHz US (20 min) with heating at 80 °C (10 min) yielded the highest extraction efficiency with 92% in the same time interval more economically for second sieving waste tea biomass. Therefore, this study has shown that it is possible to utilize UAE alone or in combination with heat extraction from tea waste for environmentally friendly, rapid, and effective polyphenol extraction.

Elemental dissolution characteristics of granite and gabbro under high-temperature water-rock interactions

In the process of developing hot dry rock (HDR) through enhanced geothermal systems (EGS), it is necessary to inject circulating water to complete thermal energy extraction. However, the injected water will react with the high-temperature rock and produce mineral dissolution, which can destroy the artificial reservoir and affect the development of geothermal energy. To explore the influence of temperature on the solution composition and mineral dissolution after water-rock reaction, this study conducted water-rock interaction experiments on gabbro and granite at different heat treatment temperatures. Subsequently, the changes of solution composition and mineral dissolution with temperature after the reaction were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and XRD. The results demonstrated that Si, Na, Ca, K, Al, and Mg did not enter the aqueous solution at the same dissolution rate. Si was the primary solute in the solution, mainly resulting from the dissolution of quartz, and the dissolution rates of metallic elements were lower. In the granite-water interaction system, metallic elements such as Na, K, Ca, and Al showed a tendency to enter the solution at low temperatures, i.e., 150–180 °C, and the dissolution rate of Si reached its peak when the water was close to the supercritical state. With the increase in temperature, the dissolution rates of Si and metallic elements showed an initial increasing trend followed by a decrease. When water is in the subcritical to the supercritical state, abrupt fluctuations in the physical properties of water can strongly affect the dissolution of minerals or rocks. The results of this study provide insights into rock corrosion fatigue and mineral scaling in EGS water environment.

Thermal Extraction: An Alternative Headspace GC–MS Method for Volatile Extractables from Medical Device Materials

Thermal Extraction: An Alternative Headspace GC–MS Method for Volatile Extractables from Medical Device Materials

Analytical model of heat transfer of U-shaped borehole heat exchanger under convolution theory and its optimal heat extraction analysis

Middle deep borehole heat exchanger (DBHE) has become widely known as one of the main ways of geothermal energy development and utilization, and the use of middle DBHE system for heating buildings has received much attention. More accurate analytical models for a coaxial borehole heat exchanger (CBHE) have been built using the convolution theorem, however, a U-shaped deep borehole heat exchanger (U-DBHE) has not been reported. Therefore, in this paper, to obtain more accurate fluid temperature distribution, an analytical model of middle DBHE considering geological stratification phenomenon is developed by using convolution theorem. The relative error of the analytical model is verified within 5% by numerical simulation. At the same time, the interaction between the three factors was analyzed and studied by response surface method: mass flow, inlet temperature and geothermal gradient on heat extraction and heat loss rate. The results reveal that for thermal extraction, the significance levels of the three factors are from large to small: geothermal gradient > inlet temperature > mass flow, for heat loss rate, the two factors of flow rate and inlet temperature are significant, and the impact of geothermal gradient is not significant. In this engineering project, when the inlet water temperature is 10 °C, the flow rate is 26.65 kg/s and the geothermal gradient is 4.5 °C/hm, there is a maximum heat extraction of 2424.16 kW.

Driver vigilance detection based on deep learning with fused thermal image information for public transportation

Autonomous-rail Rapid Transit (ART) is a new type of road public transportation with an automatic driving function, and it is one of the main places for epidemic spread. Scientific wearing of masks has been proven to be an extremely effective way to prevent an epidemic. However, drivers wearing masks make it difficult for traditional driver alert detection methods based on facial information to operate effectively. This paper proposes an ART driver alert detection system based on multimodal information fusion and deep learning, which can be applied to drivers wearing masks. The detection system is mainly divided into three modules: data acquisition module, preprocessing module, and vigilance detection module. The data acquisition module collects real-time face thermal imaging data, and environment temperature information of 13 people in the vigilance and fatigue state of the ART simulated driving environment. The preprocessing module proposes a face thermal imaging key information extraction method based on the constraints between Yolov5 and thermal image interframe constraints and extracts the mean temperature information and the hot voxel information (HV) of the eyes, forehead, and mask areas. Then the extracted information and the environment temperature information are transmitted together to the vigilance detection module for learning and classification. The vigilance detection module proposes a lightweight hybrid-attention optimization network, and this paper extracts training sets and testing sets from the data of 13 subjects. And the training set data is enhanced. Each sample is 90 frames. The maximum accuracy rate of the testing set reaches 99.57%. The feasibility of the detection system proposed in this paper is proved, which makes the thermal imaging and attention model show great potential in the application of traffic safety operation and maintenance.

Extraction of Zinc from Zinc Sublimber with Sulfuric, Thermal and Extraction Phosphoric Acid

The study was conducted to extract zinc and the results on the extraction of Zn from zinc sublime with the solution of sulfuric, thermal and extraction phosphoric acids are presented depending on Solid: Liquid (S:L), concentration and duration of the leaching process. Sulfuric acid was used with a content of 8% which is a waste product of non-ferrous metallurgy, thermal phosphoric extraction phosphoric acid from phosphorites of the Central Kyzylkum. It has been established that the maximum degree of zinc extraction is noted when using extraction phosphoric acid, which is 96-98%, S:L=1:(10-15), with the temperature of 90°C and washing sulfuric acid, which is 99.8% at S:L=1:10 and above at room temperature. Increasing the duration of the process over 30 minutes has virtually no effect on the extraction percentage of zinc.

A Multisource Collaborative Energy Extraction Circuit for Vibration, Ambient Light, and Thermal Energy With MPPT and Single Inductor

This paper presents a multi-source collaborative energy extraction circuit (MSC-EC) for vibration, ambient light and thermal energy with maximum power point tracking (MPPT) and a single inductor. The MSC-EC can simultaneously extract energy from the piezoelectric transducer (PZT) and Photovoltaic cell (PV) when the peak open-circuit (OC) voltage of the PZT is detected by the peak voltage detector and the voltage of PV is higher than the maximum power point (MPP) voltage of PV (MPP voltage is about 0.7 times the OC voltage of PV), which can also collaboratively extract energy from the thermoelectric generator (TEG) in the extraction of vibration energy or ambient light energy to improve the efficiency of thermal energy extraction. Experimental results indicate that the MPPT efficiency of PV is about 83&#x0025;, and the maximum energy extraction efficiency of TEG is about 74&#x0025;. The maximum output power of MSC-EC is 4.2 mW under certain conditions.

Revisiting thermal transport in single-layer graphene: On the applicability of thermal snapshot interatomic force constant extraction methodology for layered materials

The thermal conductivities of single-/bi-layer graphene and bulk-graphite are obtained using the Boltzmann transport equation (BTE) framework by accounting for three-phonon and four-phonon scatterings. For single-layer graphene, the thermal conductivity and interatomic force constants obtained using temperature-independent finite-difference, and temperature-dependent molecular dynamics-based approaches agree with each other. The use of the thermal snapshot approach to get temperature-dependent force constants results in a non-physical description of interatomic distances for single-layer graphene. The predicted thermal conductivity at room temperature using finite-difference based force constants is 800 W/m K, which is a severe under-prediction of experimentally measured values. For bi-layer graphene and bulk graphite, the thermal snapshot methodology is applicable and thermal conductivity changes by 25% and 5% with temperature-dependent force constants. The effect of four-phonon scattering is less than 10% on the predicted thermal conductivity of bi-layer graphene and graphite, and the obtained thermal conductivities using thermal snapshot methodology are in agreement with the literature. The limitation in the prediction of thermal conductivity of single-layer graphene via the BTE approach stems from non-accountability of temperature-dependence in finite-difference based force constants and non-physical description of interatomic bonds in thermal snapshot based force constants extraction for planar 2-atoms unitcell of single layer graphene.

A field test of medium-depth geothermal heat pump system for heating in severely cold region

Due to the worldwide attention of fossil fuel consumption and environment pollution, geothermal is recognized to be amongst the prospering alternative energy. Previous researches mainly focused on the shallow-depth geothermal heat pump systems (SD-GHPs), while medium-depth geothermal heat pump system (MD-GHPs) lacked of the experimental support especially in severely cold region. A field test of MD-GHPs using deep borehole heat exchanger (DBHE) was conducted and verified in terms of temperature variation, heat exchange and COP. The indoor temperature remained 20 °C around even though the outdoor temperature was as low as −25.10 °C. The water supply and return water temperature on the customer side performed steadfast heating characteristics that the averages were 35.13 °C and 30.97 °C. Moreover, flow rate and borehole depth are the essential influencing factors on DBHE outlet temperatures. This suggests that lifting flow rates is a fantastic option when only considering the enhancement of the thermal extraction. The DBHE average heat exchange per meter is 1000/1200 m for 61.1/84.9 W/m and 2000 m is 152.6 W/m respectively. Besides, the average heat exchange of DBHEs for working days was 485.4 kW while during Chinese New Year Holidays was 388.6 kW. Correspondingly, the average COPs for MD-GHPs ground side were 4.5 and 5.2, respectively. Results show that MD-GHPs can be extended to severely cold regions and obtain superior performance.

Evaluation of the Physicochemical and Techno-functional Properties of Gelatin Extracted from Fish Processing Waste

The current research was completed at the Indian Council of Agricultural Research - Central Institute of Fisheries Technology (ICAR-CIFT), Cochin, Kerala, India from August 2021 to August 2022 as a modified thermal extraction protocol for deriving gelatin from processing waste of skipjack tuna (Katsuwonus pelamis) skin. The study evaluated the effect of chemical composition and molecular weight contributing to the techno-functional attributes of the resulting gelatin. In the present study, we followed warm water-coupled NaCl pre-treatment to reduce the lipid content of the extracted gelatin. The extracted gelatin was characterized for Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The amount of gelatin extracted from the fish skin was 9.30±0.22%. The protein pattern of extracted gelatin on SDS-PAGE was identical to commercial grade gelatin, which implies the purity of extracted gelatin is comparable to that of commercial one. The physicochemical and functional properties were evaluated and pose remarkable techno-functional properties. Therefore, fish processing skin waste of skipjack tuna could be effectively exploited for the preparation of commercial gelatin. The extraction protocol remains environment friendly and this approach remains optimal for food technological applications. The effective exploration contributed to nutritional benefits, technological, functional, and biological functionalities for a large fraction of applications in the area of food technology, nutraceuticals, pharmaceutics, and numerous others as a future line of research.