Steam Heat Research Articles

Performance Analysis and Novel Cross-Flow Scheme of Low-Temperature Multi-Effect Distillation for Treating High-Mineralized Mine Water

Low-temperature multi-effect distillation (LT-MED) can be used to desalinate and demineralize highly mineralized mine water, facilitating the recycling and reuse of water resources. This study conducted a simulation of LT-MED technology for treating highly mineralized mine water using Aspen Plus and proposed a novel cross-flow optimization scheme. Initially, the impact of operational parameters such as process configuration, number of evaporation effects, and steam input on the gained output ratio (GOR) and scaling risk of a conventional LT-MED system was analyzed. It was found that the number of effects and heating steam flow rate had the most significant influence on GOR, while different processes exhibited limitations regarding GOR and scaling trends. To address these issues, this paper introduced a cross-flow operation process that combined forward, backward, and parallel flow. The simulation results indicated that, under conditions of eight effects, a maximum evaporation temperature of 70 °C, a temperature difference between adjacent effects of 4 °C, and a feed temperature of 45 °C, the cross-flow process—where the feed was introduced from the sixth effect—achieved the highest GOR and significantly reduced scaling risks compared to parallel and backward flow configurations. Finally, to further utilize low-pressure exhaust steam from the final effect of the cross-flow LT-MED system, mechanical vapor compression (MVC) and thermal vapor compression (TVC) were integrated into the LT-MED process. The thermodynamic performance of the coupled system was analyzed, and the simulations demonstrated that the coupled system outperformed the standalone use of either TVC or MVC, with the LT-MED-MVC-TVC system showing superior performance overall.

Thermal Evaluation of Solar Dryer’s Curve-Front utilized Heat Transfer Analysis

The sun is most sustainable renewable energy, environmentally friendly and utilized for preservation of food and agricultural crops. The main objective of this experiment research work has focused on using renewable energy for evaporated moisture of foods fruit vegetables and herbs by drying system. The heat transfer equation are analyzed to effectively harness the temperature from the sun. Experimental data obtained were used to evaluate the properties of dry air on boundary region condition. Initial, testing was carried out under without load condition, and the result shows that the ambient and dryer’s internal temperature range between 29.3-40.2˚C and 37.4-60.3 ˚C, respectively, in Thailand a latitude of 14°0'48.46" North and longitude of 100°31'49.76" East (recorded average solar radiations and temperature on January 2023 - June 2024), average solar radiations range between 312 W/m2 and 513 W/m2. The indirect natural convection was design and calculated energy base on average temperature not higher than 55˚C, utilized sun daylight at 08:00 a.m. to 04:00 p.m. local time and clear sky or partially cloudy. Second, determination of design parameters; heat energy equation and steam table analysis. Final, utilization of the design under local time, solar radiation and the climatic local conditions and test with ginger slices (represent product in order to examine weight loss). The solar dryer’s curve front shape conduced on without load showed the heat transfer coefficient natural convections range between 3.7 and 4.5 W/m2 ˚C, the energy of dry air analysis range between 54.7 and 155.2 J/s and performance of drying rate range between 0.06 and 0.82 g/s, under increasing and decreasing trends of solar radiations from the time, date and climatic local region condition.

A molten salt energy storage integrated with combined heat and power system: scheme design and performance analysis

To investigate the flexibility and economic characteristics of a molten salt-combined heat and power (CHP) integrated system under different heat sources, this paper proposes a design scheme for a molten salt-CHP system based on flue gas heat storage, comparing it with main steam heat storage and reheated steam heat source schemes. First, a molten salt heat release sub-loop is designed, where the steam heated by the molten salt can either compensate for heating demands or enter the low-pressure turbine for work, meeting the flexible operation requirements of the unit. Secondly, in response to fluctuations in temperature and pressure parameters of the main steam and reheated steam in the flue gas heat storage scheme, a water-spray desuperheating device is arranged. Finally, a simulation experiment based on a 350 MW CHP was conducted, and the results show that the flue gas molten salt heat storage technology significantly reduces energy loss on the boiler side. Underrated load, compared to the main steam and reheated steam heat storage schemes, the flue gas heat storage scheme has the highest boiler exergy efficiency and total energy utilization efficiency, at 55.8% and 59.1% respectively. During the thermal storage process, the coal consumption index of the flue gas heat storage scheme decreases with increasing load, while conversely, during the heat release process, it increases with the load. The peak-shaving capacity increases with the load, reaching 78.4 MWh under the 75% THA condition. In the steam extraction heating scenario, coupling with the molten salt subsystem can expand the safe heating operation range of the original unit, increasing the maximum peak shaving range by 13.9%, and increasing the maximum heating capacity by 65.4%.

A New Model for Steam Cavity Expansion in Vertical Wells of Heavy Oil Reservoirs

Summary Steamflooding is one of the most effective and mature methods for developing heavy oil. However, existing research has not fully explained the phenomena of steam overburden and heat loss, particularly overlooking the steam velocity loss at the steam cavity front. Therefore, the condensation heat transfer coefficient (CHTC) was introduced to describe the decrease in steam velocity at the steam cavity front. A steam cavity front expansion model, considering shape factor, pseudofluidity ratio, and CHTC ratio (CHTCR), was established and validated by using mine monitoring data. The research results show that the steam cavity of the revised model is in the shape of a “funnel,” and the steam overburden phenomenon is more pronounced at the steam cavity front. Through comparison with the field data of the P6 and P612-1 well groups, it is observed that the average displacement error of the steam cavity front of the two is only 6.58%. As steam injection progresses, the steam cavity is more degraded, and the steam overburden phenomenon is more intensified compared with the initial stage. Taking into account the phenomenon of kinetic energy loss, a higher formation heat loss rate is calculated during the middle and late stages of steam injection in the modified model. The pressure gradient at the steam cavity front is analyzed to determine an optimal displacement radius of 40 m for vertical well steamflooding in heavy oil reservoirs. When parameters such as shape factor, steam injection rate, and CHTC are increased, the development shape of the steam cavity is more ideal, but the convexity of the steam cavity front is increasingly pronounced as the pseudomobility ratio increases. The CHTC was incorporated into the steam cavity expansion model, elucidating the steam overburden phenomenon and advancing the theoretical understanding of steamflooding. By improving the existing model, the analytical formula can be used to rapidly predict the position of the steam cavity front and estimate of the steam-saturated zone, even in the absence of some field data or numerical models. Practical guidance for optimizing steam injection strategies is provided, with the potential to significantly enhance the recovery of heavy oil reservoirs.

Analyzing the Influence of Welding Process Selection on Residual Stresses in Tube-to-Tubesheet Welded Joints

Tube-to-tubesheet joints are used in the fabrication of shell and tube type heat exchangers, steam generators, boilers, condensers, and end shields of pressure tube type nuclear reactors like CANDU (Canada Deuterium Uranium) and PHWR (Pressurized Heavy Water Reactor). The weld joints connecting the tubes to the tubesheets are of prime importance as they have a direct impact on equipment safety. In the fabrication of these critical class-1 nuclear components, full penetration weld joints are used. Typically, these full penetration weld joints are created through multi-pass Tungsten Inert Gas (TIG) welding. However, more recent techniques, such as single-pass Electron Beam Welding (EBW) and Laser Beam Welding (LBW), have also been employed for this purpose. The fabrication time of these pieces of equipment containing full penetration weld joints can be drastically reduced if single-pass welding techniques are used compared to multi-pass welding techniques. However, the residual stresses developed in these joints due to the localized heat input and the substantial constraints of the tubesheet are unknown. Different welding processes, such as TIG welding, EBW, or LBW, can lead to varying levels of residual stresses in these joints, subsequently impacting their longevity. Weld residual stress plays a significant role in the initiation of failure modes of these tube-to-tubesheet welded joints, such as stress corrosion cracking, fatigue, and corrosion fatigue.This paper analyzes the residual stresses developed at the tube-to-tubesheet interface resulting from different welding techniques, such as multi-pass TIG welding and single-pass EBW/LBW. A comprehensive three-dimensional coupled thermo-mechanical finite element analysis is employed for this purpose. The findings reveal a significant difference, with single-pass EBW exhibiting up to 32% lower residual stresses compared to multi-pass TIG welding. Additionally, the Heat Affected Zone (HAZ) in EBW is approximately 50% smaller than in TIG welding, and the equivalent distortion in EBW is reduced by 90% compared to multi-pass TIG welding. In summary, this investigation concludes that single-pass EBW offers distinct advantages for tube-to-tubesheet weld joints, including reduced residual stresses, a smaller HAZ, and lower distortions.

Analysis of Mechanisms and Environmental Sustainability in In Situ Shale Oil Conversion Using Steam Heating: A Multiphase Flow Simulation Perspective

Shale oil as an unconventional energy source holds significant extraction value. However, traditional extraction techniques often entail significant environmental impacts, emphasizing the need for more sustainable and environmentally friendly methods. In situ conversion of shale oil using superheated steam fits this bill. Based on this, we used a new TFC coupling simulator to build a geological model, providing a comprehensive depiction of the evolution process of various elements during in situ conversion by steam, thereby investigating the feasibility of this method. The results show that based on the temperature distribution within the shale oil reservoir during the heating stage, the area between the heating well and the production well can be divided into five regions. In addition, the steam injected contributes to driving the oil. However, due to the relatively low energy density of the steam, a large amount of steam needs to be injected into the reservoir in order to attain the intended heating outcome, resulting in a high ratio of liquid water in the produced products. Meanwhile, the evolution of components during in situ conversion is influenced by factors such as the injection rate of steam and soaking time. A slow injection rate and prolonged soaking time are both adverse to extraction of shale oil. On this basis, the in situ conversion heating strategy can be refined.

Life cycle cost approach involving steam transport model for insulation thickness optimization of steam pipes

Efficient steam pipe insulation is critical for minimizing heat loss during transportation, ensuring the economic viability of thermal processes or end-user applications. Unlike water-based systems, steam heat loss mechanisms are intricate, predominantly influenced by the transition of steam to condensate which introduces latent heat, thus significantly impacting overall heat loss. This study employs a life-cycle cost approach, integrating a comprehensive steam transport model to evaluate the optimal insulation thickness under varying temperature, flow rates and composite insulation schemes. The steam transport model incorporates a drainage energy loss term, providing a detailed depiction of the energy balance along the steam pipe. Results from the steam transportation simulation conducted on a single long pipe demonstrate a ∼4.6 % deviation between simulated and measured heat loss values. Furthermore, Life cycle cost analysis highlights the economically advantageous insulation configuration, comprising an aerogel blanket as the inner layer and glass wool as the outer layer. With increasing temperature, augmenting the proportion of aerogel blanket yields economic benefit, with the optimum thickness exhibiting a linear growth trend. Conversely, as the flow rate increases, the optimum insulation thickness remains constant.

The role of annealing and grain boundary controls on the mechanical properties of limestones and marbles

Chemical and mechanical processes are coupled in many geological and geochemical environments. Reactive processes anneal defects and restructure grain boundaries, modifying their elastic properties, levels of internal friction, wave propagation rates and fracture behaviors. The nature of these changes is, however, contingent on the initial state of the rock. In this study, impulse excitation was used to measure changes in mechanical properties as a function of dry and steam heating time at 300 °C for three carbonate rocks: Carrara marble, Carthage marble (Burlington Limestone), and Texas Cream limestone (Edwards limestone), with initial porosities of about 1 %, 3 %, and 27 %, respectively. Frequency-dependent phenomena along with mineral recrystallization were observed. This was coupled with small-angle X-ray and neutron scattering analysis to determine the relationship between changes in bulk mechanical and microstructural properties. An observed decrease in both the Young's and shear moduli in the experimental limestones as a function of heating time reflects and quantifies a reduction in the stiffness of the rock due to annealing. The internal friction of the samples first increases then decreases with reaction time, reflecting defect annealing, but this was balanced against grain boundary dissolution apparently driven by condensation of steam in the confined grain-boundary environment. This suggests an increase in the boiling point under confinement leading to dissolution, increased porosity and widening of the grain boundaries. In addition, comparison of small-angle X-ray and neutron scattering results suggests that it is inappropriate to assume that pores are empty for quantitative analysis of typical small-angle scattering samples.

Thermal modification of Lantana camara stalks and its characterization

Abstract This paper deals with value addition and utilization of Lantana camara, an invasive species with unprecedented rate of growth, by thermal modification. Lantana camara stalks were thermally modified using vacuum heat treatment (VHT), oil heat treatment (OHT), and steam heat treatment (SHT) at 180 °C and 200 °C and subsequently changes in physical, chemical and mechanical properties were studied. Weight loss was observed in vacuum and steam heat treated samples due to thermal degradation while oil heat treated samples showed weight gain due to oil uptake. SHT exhibited the highest (19 %) weight loss at 200 °C. The color of the modified lantana attained uniform dark colour, OHT exhibited the most intense effect on colour changes. Fourier transform infrared (FTIR) and Fourier transform near infrared (FTNIR) spectroscopic analyses indicated degradation of hemicellulose and change in cellulose crystallinity due to heat treatment. Dimensional stability of thermally modified Lantana stalks improved across treatments, with SHT achieving the highest anti-swelling efficiency of 67.3 % at 200 °C and lowest water absorption (43 %) after 72 h of water soaking. The dynamic modulus of elasticity of thermally modified Lantana remained constant in all the treatment processes. Overall, the results indicate that thermal modification can increase utilization potential of L. camara.

Part-load performance analysis of a modular biomass boiler with a combined heat and power industrial Rankine cycle and supplementary sCO2 Brayton cycle

Abstract The addition of a supplementary high efficiency cycle integrated with an existing steam power cycle may increase energy efficiency and net generation. In this paper, part load performance and operation of a modular biomass boiler with an existing industrial Rankine steam heat and power cycle and supplementary supercritical CO2 (sCO2) Brayton cycle is analysed. The aim is to leverage the high efficiency of the sCO2 cycle by retrofitting sCO2 heaters in the existing biomass boiler, increasing net power output and thermal efficiency. With nominal load performance previously investigated, understanding part-load performance and operation is vital to determine cycle feasibility. A quasi-steady-state one dimensional thermofluid network model was used to simulate the integrated cycle performance for loads ranging from 100% to 60%. The model solves the mass, energy, momentum, and species balance equations, capturing detailed component characteristics. Two control methodologies are explored for the sCO2 Brayton cycle, namely inventory control and inventory control combined with throttling valve control. Inventory control is selected as the better performing control strategy for load following, maintaining high thermal efficiency across partial loads. At 60% load, the sCO2 compressor operates near the pseudo-critical point, leading to a sharp decrease in sCO2 cycle capacity, which requires careful management of inventory control. Two sCO2 heater configurations are investigated, namely a single convective-dominant heater, and a dual heater configuration with a radiative and a convective heater. The single heater configuration is preferred to minimise adverse impacts on the Rankine cycle superheaters.

Study on the Continuous Whole Process Preparation of Peptizable Pseudoboehmite by High Gravity Strengthening Reaction of CO2 and Heat Transfer.

The preparation of highly peptizable pseudoboehmite faces challenges such as slow reaction rate, prolonged aging times leading to poor peptization performance, and difficulty in achieving continuous production. In this study, a novel approach was proposed involving a high gravity reactor to enhance carbonation reaction control for pseudoboehmite nucleation, a high gravity steam heating process, and a continuous aging process in pipelines. By coupling these three processes, the continuous whole process production of highly peptizable pseudoboehmite under high gravity conditions was achieved. First, the effect of high gravity reactor enhancement on the reaction and the resulting solid phase was investigated. Second, the impact of aging temperature and time on the solid phase formed at different reaction end points was studied using high gravity and steam heating of the liquid phase. Furthermore, the influence of synthesis conditions on the peptization performance of pseudoboehmite was extensively examined. Finally, the nucleation and growth mechanisms of pseudoboehmite under high gravity conditions were analyzed. It was found that increasing high gravity factor, CO2 gas flow rate, and CO2 content accelerated carbonation reaction rate, promoting pseudoboehmite crystal nucleation. Increasing aging temperature and time facilitated the growth of pseudoboehmite nuclei and improved peptization performance. The high gravity device altered the gas-liquid phase contact state of traditional kettle-type equipment, reducing the reaction time and heating time from minutes to seconds, thus achieving the continuous whole process production of pseudoboehmite with a peptization index of 100% from sodium aluminate solution by kiln flue gas.

The Simulator of China General Nuclear Power Group (CGNPC) Delingha 50 MW Parabolic Trough Solar Thermal Power Plant

CGN Delingha 50MW parabolic trough solar power plant is China's first commercial trough solar power station. There are 190 heat collecting loops in the solar field of the power plant. Due to the mutual coupling of heat collecting loops layout location, environmental conditions, medium flow, working medium physical property changes and other factors, the hydrodynamic characteristics of the solar field are complex. In practical operation, balancing the flow of the heat absorbing medium in each loop of the large-scale trough solar thermal power plant and stabilizing the outlet medium temperature are difficult problems. Taking CGN Delingha 50MW parabolic trough solar power plant as the research object, this paper adopts the idea of modular modeling to establish the mathematical model of the main equipment in different systems of the power plant, to build the dynamic model of its solar field, steam generation system, heat storage system and steam turbine system. Based on the parallel computing function of the real-time dynamic simulation platform STAR-90, the real-time coupling calculation between different systems is realized. The error of the built model in steady-state is less than 2%, and the dynamic results of the model are in good agreement with the actual operation data. The modeling method in this paper is universal and can be a reference for dynamic modeling of other large-scale trough solar thermal power plants.

COMBUSTION OF HYDROGEN IN OXYGEN-STEAM MIXTURE FOR INCREASING THE STEAM TEMPERATURE OF POWER PLANTS

In the work the problems that arise at combustion of hydrogen in oxygen-steam mixture for the purpose of combustion products (steam) mixing for heating steam, which is planned to be used in steam turbines of power plants were researched. The main problem is the formation of underburning H2 and, accordingly, the presence of O2, which have a negative effect on metals, and it will also prevent steam condensation in the condenser was determined. For solve this problem, calculations of the equilibrium concentrations of chemical reaction products in the combustion zone depending on the amount of ballast steam added to the oxidizer (oxygen) for the initial conditions: T0=528 K, p=0.1 MPa; T0=​​528 K, p=3.1 MPa; T0=​​584 K, p=10 MPa were made. The corresponding adiabatic temperatures were calculated. The dilution of the oxidant (oxygen) with steam significantly decreases the adiabatic temperature (Tb) and reduces the equilibrium concentrations of other substances in the combustion zone, but at the same time the laminar flame propagation velocity (SL) also significantly decreases was established. It is important when a certain concertation of ballast steam is achieved (the final percentage is determined by the design of the burner) there will be a sharp deterioration of combustion or even the formation of a flame will be impossible. The principal design of the hydrogen-oxygen-steam combustion chamber was proposed. The necessity of heating oxygen and hydrogen and the principle of determining the pressure under which it is advisable to supply oxygen and hydrogen to ensure the maximum intensification of mixing first of oxygen and steam, and then of the formed mixture and hydrogen, were substantiated. Bibl. 20, Fig. 5, Table 3.

Waste to hydrogen: Investigation of different loads of diesel engine exhaust gas

In this study, green hydrogen production by utilizing diesel engine exhaust gas waste heat in steam and organic Rankine with internal heat exchanger with two thermoelectric generators and proton exchange membrane electrolyzer combined system under different load conditions is investigated. Thermo-economic, enviro-economic and exergo-environmental analyses of the maximum hydrogen production point determined for different waste heat conditions are carried out. Total and specific investment cost and levelized cost of hydrogen determined under different loads are compared. Simple and dynamic payback period, profit ratio of investment and net present value of the combined system at different selling prices of hydrogen are determined and their feasibility is analyzed. Carbon reduction and carbon credit gain amount due to green hydrogen produced in line with zero emission targets are compared under different waste heat conditions. Exergetic sustainability index of the system were determined within the scope of exergo-environmental analysis. In terms of economic and environmental performance, a hydrogen cost of 2.04 $/kg was obtained under 100% load and a carbon saving of 7211 $ was achieved depending on the hydrogen produced. Dynamic payback period and net present value were found to be 4.467 years and 404,696 $, respectively, if the hydrogen selling price was 5 $/kg under 100% load. It is found that a 50% load reduction leads to an increase in dynamic payback period and levelized cost of hydrogen by 18.6% and 13.72%, respectively, and a decrease in net present value and profit ratio of investment by 54.39% and 12.39%, respectively. On the other hand, since the exergy destruction decreases with the decrease in the load, exergo-environmental index is found to decrease by 2.03%.

Thermal Analysis of Infrared Heater as an Alternative Heat Source for Flexitank Application Using CFD

The heating pad was a mechanism for heating elements using steam as a heat source and heating the liquid inside a flexitank to liquidise for easy discharge completely. Alternative heat sources such as infrared, electric, and exothermic reactions may improve thermal performance for the heating process. Infrared heating is chosen for this study due to its efficient radiation heat transfer compared to conduction and convection. This study aims to determine the optimal infrared heater configuration to improve the time to liquidify fluid on the flexitank for easier discharge. Nine flexitank and infrared heater geometries were made using SolidWorks with different heater positions and heating element thicknesses. Each geometry was simulated using Ansys Mechanical to study the thermal performance of radiation heat transfer with three different heating element materials. The heat output and energy input obtained from the simulation were used to calculate heating time and energy efficiency, respectively. The effects of each parameter were studied to determine the best configuration of the infrared heater in terms of heating time, energy consumption and both. The results showed that the position of the heater plays the most crucial role in determining the heating time and energy consumption, as a heater position that produces a larger heated surface area on the flexitank can reduce heating time. The thickness of the heating element and its material contributes a minor impact on heating time and energy consumption. Increasing thickness would lower the heating time and increase energy efficiency if the thickness improves heat retention capabilities. Increasing material emissivity will increase the heating time. Higher conductive materials would use more energy compared to lower conductive materials. The heating time was improved by about 30% compared to a steam heating pad. Energy consumption was reduced by about 85% compared to a small steam generator. In conclusion, the infrared heater was a promising alternative as a heat source for flexitank applications.

Feasibility and recovery efficiency of in-situ shale oil conversion in fractured reservoirs via steam heating: Based on a coupled thermo-flow-chemical model

Shale oil is a type of liquid hydrocarbon obtained through the pyrolysis of organic matter such as kerogen in oil shale reservoirs. Effective extraction of shale oil can significantly alleviate the pressure on oil supply. Among the various methods proposed for shale oil extraction, in-situ conversion of shale oil through high-temperature steam heating is a promising technique. This study employs a newly developed thermo-flow-chemical numerical simulator to establish a heterogeneous geological model and provides a detailed description of the evolution of different components within the shale oil reservoir during the in-situ conversion process. Additionally, the study thoroughly analyzes the role of high-permeability channels, such as fractures, in fluid transport and heat transfer during this process. In comparison with homogeneous reservoirs, fractures play a controlling role in the transport of steam. After injection, steam forms a preferential transport path between the heating well and the production well through the fractures. Subsequent injected steam will preferentially travel through this path, leading to faster heating of the reservoir. However, the uneven distribution of fractures may result in incomplete pyrolysis of the organic matter within the reservoir. Additionally, we found that the producing pressure and the steam injection rate significantly affect the pyrolysis of kerogen and the production of oil and gas. Both excessively low producing pressure and excessively high steam injection rate are detrimental to shale oil extraction. Based on these findings, this study aims to develop more rational heating strategies for reservoirs with different characteristics.

Thermodynamic analysis of a solar-driven supercritical water gasification-oxidation system for ammonia production and heat supply from chicken manure

Faced with the dual challenges of energy shortage and environmental pollution, researchers are turning to extracting clean energy from waste resources. The coupled system of solar energy and supercritical water gasification offers a novel solution to these issues. In this study, a solar-driven supercritical water gasification-oxidation system for ammonia production and heat supply from chicken manure was simulated. Additionally, the effects of temperature of supercritical water gasification, chicken manure slurry concentration, water-dry matter ratio, and pressure of supercritical water gasification and oxidation on the system's products, efficiency, and device exergy losses were examined. Under typical working conditions (the temperature of supercritical water gasification: 750 °C, chicken manure slurry concentration: 50 wt%, water-dry matter ratio: 5, the pressure of supercritical water gasification and oxidation: 25 MPa), and the system had a treatment capacity of 5 t/h of dry chicken manure. The system yielded 2604.04 kg/h of NH3 and 23763.9 kg/h of heating steam. It demonstrated an energy efficiency of 68.38% and an exergy efficiency of 46.85%. The total exergy losses of the system amounted to 34704.73kw, with the solar collector accounting for the largest share at 49.6%. The temperature of supercritical water gasification and water-dry matter ratio significantly impacted the system efficiency. Conversely, chicken manure slurry concentration and the pressure of supercritical water gasification and oxidation exerted minimal influence. The solar collector and gasification reactor emerged as the primary contributors to exergy losses in the entire system. Notably, the lower temperatures of supercritical water gasification, chicken manure slurry concentrations, pressures of supercritical water gasification and oxidation, and water-dry matter ratios can reduce exergy losses in both the solar collector and the gasification reactor.

Evaluation of Heating Pad using Electrical Heating Element for Flexitank Transportation Application

Liquid transportation is accomplished in various ways, including the use of tankers and containers. Recently, most liquid shipments have utilized Flexitank as liquid containers, where steam heating is employed to melt frozen cargo liquids. However, due to limitations and disadvantages associated with steam-type heating pads, particularly in terms of the time taken to melt the liquid, researchers are exploring alternative methods for heating liquid within the Flexitank. This project aims to investigate the possibility of implementing electrical heating pads as an option for liquid heating in liquid transportation. Various types of electrical heating pads have been studied to explore their characteristics and operational capabilities. Experimental testing has been conducted on several electrical heating pads to compare their characteristics, especially in terms of the desired temperature requirement for specific liquid temperatures, as well as current consumption for each heating pad. This study will assist in determining the best option for implementing electrical heating pads in Flexitank. The results show a promising future for electrical heating pads in Flexitank, but further study is required to examine various heating pad arrangements in actual implementation.

Realizing the Direct Synthesis of High Silica IWS Zeolite with Improved Hydrothermal Stability.

Direct synthesis of germanosilicate zeolites with low Ge content and improved hydrothermal stability is a great challenge. Herein, we successfully achieve the direct synthesis of IWS zeolite with a Si/Ge ratio higher than 4 for the first time. High silica IWS zeolites can be prepared in a wide range of Si/Ge ratios (4-16) by utilizing bulky 1,3-bis(1-adamantyl)-imidazolium (BAdaI+) as an efficient organic structure-directing agent from the concentrated synthesis gel under fluoride conditions. It is proven by a series of characterizations that Ge atoms preferentially occupy the double-four-ring (D4R) units. Theoretical calculations reveal the preferential interactions of guest organic structure-directing agents (OSDAs) and host IWS zeolites with different Si/Ge ratios. The introduction of more Ge atoms cannot improve the host-guest interaction when the BAdaI+ molecule is accommodated within the nanopores of IWS zeolite compared to other OSDAs. The obtained IWS zeolite shows an extremely high specific surface area (905 m2/g) and pore volume (1.31 cm3/g). Due to the low Ge content, IWS zeolite exhibits outstanding hydrothermal stability and experiences high temperature steam heating with no loss of crystallinity and only a slight loss of microporosity.

Integrated processes (HPSE+scCO2) to prepare sterilized alginate-gelatine-based aerogel

Biopolymers application in biomedical areas has been limited due to the physicochemical degradation that occurs using conventional processing/sterilization methods (e.g., steam heat, γ-radiation, ethylene oxide). Aiming to avoid/minimize degradation and preserve their properties, supercritical carbon dioxide (scCO2) has been proposed as an alternative sterilization method for such materials. ScCO2 can simultaneously be used as a drying method to produce aerogels (i) and sterilize them (ii). However, a solvent exchange is required to prepare the alcogel from hydrogel, achievable through high-pressure solvent exchange (HPSE) (iii). This study integrated three processes: HPSE, scCO2 drying, and sterilization to prepare alginate-gelatine sterilized aerogels. Two scCO2 sterilization methods were tested. Results showed that sterilization did not compromise the aerogels’ chemical, thermal and swelling properties. Conversely, Young’s Modulus increased, and BET surface area decreased, due to the structural changes caused by the fast pressurization/depressurization rates applied during sterilization. Regarding the sterilization efficiency, results showed a reduction in contamination throughout the process, achieving a SAL of 10-4. The sterilized aerogels were non-cytotoxic in vitro and showed improved wound-healing properties. The innovative integrated process produced decontaminated/sterile and ready-to-use aerogels reducing process time by 75 %, from 2 days up to 12 h without compromising the aerogel’s properties.