Dry Steam Research Articles

Superheated steam drying and torrefaction of wet biomass: The effect on products characteristics

Superheated steam drying and torrefaction of wet biomass: The effect on products characteristics

Role of advanced cleaning and sanitation techniques in biofilm prevention on dairy equipment.

Biofilm formation on dairy equipment is a persistent challenge in the dairy industry, contributing to product contamination, equipment inefficiency, and economic losses. Traditional methods such as manual cleaning and basic chemical sanitation are discussed as foundational approaches, followed by an in-depth investigation of cutting-edge technologies, including clean-in-place systems, high-pressure cleaning, foam cleaning, ultrasonic and electrochemical cleaning, dry ice blasting, robotics, nanotechnology-based agents, enzymatic cleaners, and oxidizing agents. Enhanced sanitation techniques, such as dry steam, pulsed light, acidic and alkaline electrolyzed water, hydrogen peroxide vapor, microbubble technology, and biodegradable biocides, are highlighted for their potential to achieve superior sanitation while promoting sustainability. The effectiveness, feasibility, and limitations of these methods are evaluated, emphasizing their role in maintaining dairy equipment hygiene and reducing biofilm-associated risks. Additionally, challenges, such as equipment compatibility, cost, and regulatory compliance, are addressed, along with insights into future directions and innovations, including automation, smart cleaning systems, and green cleaning solutions. This review provides a comprehensive resource for researchers, industry professionals, and policymakers aiming to tackle biofilm formation in dairy production systems and enhance food safety, operational efficiency, and sustainability.

Evaluation of the effectiveness of biodisinfection in different indoor environments through dry steam using 6% hydrogen peroxide and silver ions

Evaluation of the effectiveness of biodisinfection in different indoor environments through dry steam using 6% hydrogen peroxide and silver ions

First-Principles Kinetic Monte Carlo Simulations for Single-Cluster Catalysis: Study of CO2 and CH4 Conversion on Pt/HfC.

The deposition of small transition metal (TM) clusters on transition metal carbides (TMC) gives rise to bifunctional catalysts with multiple active sites. This family of single-cluster catalysts (SCCs) offers exciting opportunities for enabling a wider range of chemical reactions owing to their strong metal-support interactions, which drastically modify the catalytic properties of the supported metal atoms. In this work, we use first-principles Kinetic Monte Carlo (KMC) simulations to investigate the conversion of CO2 and CH4 on Pt/HfC, which was identified as the most promising TM/TMC combination in a previous DFT-based high-throughput screening study. We analyze the interplay between the Pt clusters and the HfC support, evaluating the catalytic activity, selectivity, and adlayer composition across a broad range of operating conditions (p A , p B , and T) and Pt loadings. This study evaluates five different industrial processes, including the dry reforming (DRM), steam reforming (SRM), and partial oxidation (POM) of methane, as well as the water-gas shift (WGS) reaction and its reverse (RWGS). Our results demonstrate that the deposition of Pt clusters on HfC systematically enhances the catalytic performance, even at a Pt loading as low as ∼0.02 ML. This work illustrates the extensive catalytic benefits of SCCs and highlights the importance of considering diffusion steps and lateral interactions in kinetic modeling.

Heat storage for the coupling of Waste Heat Recovery and hydrogen production in a Solid-Oxide electrolyser

The dihydrogen molecule H2 is set to play a major role in future energy systems, both as a component of fuels or synthesis gases, and as an energy carrier for long-term electricity storage. Water electrolysis technologies based on renewable electricity represent a credible decarbonized alternative to current H2 production by steam reforming, which emits high levels of CO2. Among these, Solid Oxide Electrolysis Cells (SOEC) have significant potential for achieving low-cost, decarbonized production (Reytier et al., 2015). To operate efficiently, a SOEC system needs a thermal management system capable of heating incoming streams up to the SOEC operating temperature (700-850°C). For the superheating stage, between 150°C and the operating temperature, the heat from the SOEC outflows is generally recovered in high-temperature exchangers (Min, Choi and Hong, 2022). Consequently, dry steam generation represents the largest thermal energy consumption of the system and has a significant impact on the overall efficiency of hydrogen production. In this work, a thermal system is designed to generate steam from waste heat in the form of industrial gases. This thermal system is modelled using Dymola software based on the Modelica language. In this way, it is possible to dynamically simulate the thermal system response to variations in the flow rate and temperature of the industrial waste heat. In the proposed thermal architecture, the heat from the waste heat flux is extracted through a tube bundle heat exchanger to heat a primary thermal oil loop. The hot thermal oil is then used in a plate steam generator to, first, heat the secondary flow of liquid water up to the saturation temperature, and second, evaporate water to produce steam. High-temperature heat exchangers are finally used to recover heat from the SOEC system output streams. Thermocline sensible storage is added to the primary oil loop to maintain a constant secondary flow of steam to the SOEC despite the highly variable availability of industrial waste heat. An electric heater is also added to the oil loop, as a back-up. The entire thermal system is controlled by various pumps and valves located in the oil loop and at the level of the industrial exhaust. Ultimately, real temperature and flow data from the exhaust gases of an industrial plant are used to size and test the thermal architecture. The heat exchangers are modeled in 0D using the LMTD method. A 1-tank thermocline thermal storage with a rock bed is chosen in this study. The use of a rock bed reduces the total amount of expensive thermal oil contained in the thermal storage system, and therefore its total installation cost. This also influences the thermal stratification of the fluid. The thermocline storage is modeled in 1D along the vertical axis. Conductoconvective exchange between the oil and the rocks, conduction between the rocks and conduction in the oil in the vertical direction are considered. Finally, the SOEC system is represented by a stationary model based on experimental results. The thermal system is designed and controlled to maintain the hydrogen production in the SOEC constant during the operation of the industrial plant, whatever the temperature and flow rate of the recoverable industrial gases. When too little thermal power is available from the industrial gases, it is possible to switch on the electric heater or extract hot oil from the thermal storage. The sizing of the various components and the control strategy are studied with the aim of optimizing the thermal architecture according to the following criteria: energy efficiency, power consumption and cost of dihydrogen production. By implementing the steam generation system described in this work, the overall power consumption and operating costs of the hydrogen production system can be reduced by around 15%.

Analysis of Allergies and Optimization in Kamojang Dry Steam Type Geothermal Power Plant With A Capacity of 55 MW

This study aims to analyze the exergy efficiency and irreversibility of the Kamojang Unit 2 Geothermal Power Plant (GPP) in Indonesia using an exergy analysis method. The results reveal that the turbine exhibits the highest exergy loss of 11,512 kW with an exergy efficiency of 82.78%. The condenser records the second-largest exergy loss of 9,875 kW, while the inter condenser and after condenser show the lowest exergy efficiencies at 22.6% and 38.55%, respectively. The overall system exergy efficiency is 65.3%, producing 63,261 kW of electricity from an input exergy of 96,764 kW. Optimization was conducted by varying the turbine inlet pressure from 4.5 to 6.5 bar, with the optimal pressure determined to be 4.5 bar, resulting in the highest exergy efficiency and the lowest irreversibility. This research provides valuable insights for enhancing geothermal power plant efficiency through thermodynamic parameter optimization.

Solvent and Catalyst-Free Depolymerization of Polylactic Acid Waste to Lactide Enabled by Dry Steam

Solvent and Catalyst-Free Depolymerization of Polylactic Acid Waste to Lactide Enabled by Dry Steam

Thermodynamics to economic analyses of geothermal-driven hydrogen energy systems

Thermodynamics to economic analyses of geothermal-driven hydrogen energy systems

Effects of different postharvest drying processes on flavonoid content and enzymatic activity of Styphnolobium japonicum (L.) Schott flowers for industrial and medicinal use

Traditionally, fresh S. japonicum flowers (SJF) and S. japonicum flowers buds (SJFB) are dried prior to further processing and use. Here, we investigated the ways in which drying techniques, including sun drying (SD), steam drying (STD), microwave drying (MD), hot air drying (HAD, 40 °C, 60 °C, 80 °C, 100 °C), and freeze drying (FD), alter the flavonoid composition of freshly-harvested SJF and SJFB. The flavonoid content of dried samples was determined by Ultra High Performance Liquid Chromatography-Diode Array Detector (UPLC-DAD). Overall, different drying techniques had significantly different effects on the RU content, ranging from 10.63 % (HAD-80 °C) to 34.13 % (HAD-100 °C) in SJF and from 18.91 % (HAD-100 °C) to 29.16 % (HAD-40 °C) and 30.53 % (SD) in SJFB. To clarify the mechanism by which drying affects the RU content of S. japonicum flowers, we studied the activity of a rutin-hydrolyzing enzyme (RHE) isolated from SJF and SJFB using multiple separation and assay methods. According to the Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) results, the apparent molecular weight of the purified RHE was approximately 38 kDa. According to UPLC-DAD, RHE catalyzes the production of quercetin (QU) from rutin (RU), but not from other flavonoid glycosides. Drying fresh SJF and SJFB at low and high temperatures can inhibit RHE activity and prevent RU hydrolysis. Therefore, subjecting freshly-harvest SJF to HAD-100 °C, and freshly-harvest SJFB to SD or HAD-40 °C, can greatly increase the RU content. In particular, HAD is viable for large-scale application due to its simplicity and industrial feasibility.

Energy and exergy analysis of dry and steam external reformers for a power cycle based on biogas-fueled solid oxide fuel cell

Energy and exergy analysis of dry and steam external reformers for a power cycle based on biogas-fueled solid oxide fuel cell

Numerical investigation of discharge pressure effect on steam ejector performance in renewable refrigeration cycle by considering wet steam model and dry gas model

Abstract In recent times, steam ejectors have garnered significant interest among researchers due to their environmental friendliness and the utilization of low-grade energy sources. However, a key drawback of the ejector refrigeration cycle (ERC) is its relatively low coefficient of performance (COP). Understanding the behavior of ejectors under various operating conditions is crucial for addressing this concern. This study specifically focuses on investigating the flow characteristics of ejectors in the single-choking mode. Both dry steam model (DSM) and wet steam model (WSM) are employed to analyze and evaluate the performance in this study. Based on the findings, it is evident that the discharge pressure (DP) significantly influences the flow characteristics. With increasing DP, there is a decrease in the Mach number and liquid mass fraction (LMF) within the ejector, while the temperature distribution shows an upward trend. Additionally, as the DP increases, there is a notable decline in the entrainment ratio (ER) and production entropy. With an increase in the DP, both the DSM and WSM exhibit similar trends. However, in the DSM, the ER reaches zero at an earlier stage compared to the WSM. Specifically, when the DP rises from 5000 Pa to 5600 Pa, there is a 12.6 % increase in the production entropy in the WSM, while the DSM experiences a slightly higher increase of 12.9 %.

Dry reforming of methane at high temperature and elevated pressure over nickel spinellized powder catalyst and pellets prepared from a metallurgical residue

AbstractThe coke deposition on catalysts is a significant problem in the dry reforming of methane at elevated pressures. Understanding and controlling the mechanisms of such deposition is essential in developing a techno‐economically viable industrial application for the production of synthesis gas and/or hydrogen. The patent‐pending nickel‐supported upgraded slag oxide (Ni‐UGSO) catalysts, in powder form, have demonstrated excellent performance and achieved equilibrium in dry reforming, steam reforming and mixed methane reforming in a gram‐scale laboratory packed bed reactor under barometric pressure. In this extended study, Ni‐UGSO pellets were prepared using the wet impregnation method. The pelletized form of said catalyst was studied under elevated pressure to imitate the industrial operating conditions in a kilogram‐scale laboratory packed bed reactor. The characterization of the fresh and used catalytic formulation produced data allowing the investigation of the physicochemical properties of catalysts and the effects of metal dispersion, reaction pressure and crystallite size, as well as the role of side reactions on the nature of the coke. The metal support nature favored the interaction between the Ni metal and spinels (UGSO), and the presence of the clay binder (kaolinite, quartz) improved the pellet morphology, provided higher Ni dispersion, maintained the crystallite size, reduced the coke formation and achieved similar or higher performance with respect to Ni‐UGSO powder despite having 85% less surface area. The Ni‐UGSO pellet showed negligible coke deposits from 1 to 6.5 atm and operated successfully for 24 h at 5.5 atm, 800°C and gas hourly space velocity 810 L/(h kg cat). This study provides new insight into the design of a more efficient and robust catalyst for methane dry reforming at elevated pressures, which is critical for potential future transfer at the industrial level.

Emerging trends in hydrogen and synfuel generation: a state-of-the-art review.

The current work investigated emerging fields for generating and consuming hydrogen and synthetic Fischer-Tropsch (FT) fuels, especially from detrimental greenhouse gases, CO2 and CH4. Technologies for syngas generation ranging from partial oxidation, auto-thermal, dry, photothermal and wet or steam reforming of methane were adequately reviewed alongside biomass valorisation for hydrogen generation, water electrolysis and climate challenges due to methane flaring, production, storage, transportation, challenges and opportunities in CO2 and CH4 utilisation. Under the same conditions, dry reforming produces more coke than steam reforming. However, combining the two techniques produces syngas with a high H2/CO ratio, which is suitable for producing long-chain hydrocarbons. Although the steam methane reforming (SMR) process has been industrialised, it is well known to consume significant energy. However, coke production via catalytic methane decomposition, the prime hindrance to large-scale implementation of these techniques for hydrogen production, could be addressed by coupling CO with CO2 conversion to alter the H2/CO ratio of syngas, increasing the reaction temperatures in dry reforming, or increasing the steam content fed in steam reforming. Optimised hydrogen production and generation of green fuels from CO2 and CH4 can be achieved by implementing these strategies.

Combined effects of low pressure superheated steam drying and vacuum drying on sugar reduction and quality attribute in mango (Mangifera indica L.) slices

Abstract Consumers paying more attention to physical health has led to an increasing market demand for low-sugar dried fruit products. The quality of products dried via low pressure superheated steam drying (LPSSD) is not only superior to those dried via conventional hot air or vacuum drying (VD), but also has the potential to reduce sugar content. In order to elucidate the mechanism of reducing the sugar of mango slices by LPSSD and obtain low-sugar dried mango slices, the combined effect of LPSSD–VD on mango slices was studied and an evaporation experiment of a sugar solution in a low pressure superheated steam environment was performed. This study revealed that the sugar reduction of mango slices was mainly due to the superheated steam carryover phenomenon in the second half of the constant-temperature stage and the occurrence of Maillard reaction during LPSSD. The quality attributes of mango slices dried using LPSSD–VD was improved compared with LPSSD and VD. As a result, LPSSD–VD could be used to regulate the sugar content in dried fruit and provide a theoretical basis for the production of low-sugar preserved fruits.

The effects of dry heat and steam on germination of dry and imbibed seeds of the invasive garden lupine (Lupinus polyphyllus Lindl.)

AbstractRegularly mown road verges are an important habitat for conservation of grassland vegetation. Disturbance and movement of seed-contaminated soil during road construction and maintenance makes road verges susceptible to the establishment of invasive alien plants such as garden lupine (Lupinus polyphyllus Lindl.). To combat the spread of L. polyphyllus via seeds, we tested methods for seed destruction using heat. This study aimed at developing heat eradication methods for dry and imbibed L. polyphyllus seeds applying dry heat (88, 93, 98, 103 C for 1, 3, 5, 10 min) in a laboratory, steam (85, 90, 95 C for 3, 5, 10 min) in a test box steaming device, and (97 C at 10 to 17 min; dry seeds only) in a stationary soil-steaming machine (S30). To speed up water absorption and posttreatment germination, the imbibed seeds were manually scarified before the heat treatment and the dry seeds afterward. Additionally, germination of two seed batches of different ages was tested applying dry heat (88, 98 C at 3, 5 min). Steam treatments inhibited seed germination more than dry heat in both dry and imbibed seeds. Germination dropped to <5% when steamed at ≥90 C or dry heated at >100 C. Seed germination decreased with higher temperatures and longer exposure times. Imbibed seeds exhibited lower germination compared with dry seeds for dry and steam heat. Approximately 0.5% of dry seeds germinated when steamed using the S30. The seeds collected in 2022 were less sensitive to dry heat than seeds from 2020. In conclusion, hot steam is more effective in reducing L. polyphyllus seed germination than dry heat. Thus, to successfully eradicate L. polyphyllus seeds in soil masses, we recommend steaming them at 97 C for at least 10 min.

Experimental and Numerical Study of Superheated Steam Drying for Sliced Avocado

AbstractSuperheated steam drying (SSD) of sliced avocado is studied by both experiment and theory. An experimental system is built to evaluate the effects of drying temperature and gas velocity on the evaporation rate and color change of the product. Experiments are conducted for ripened Booth avocado from Daklak province of Vietnam. Experimental results show that evaporation is faster at higher temperatures and velocities, but the effect of temperature decreases at higher velocities. At temperatures below 130 °C, the product is not brown, but at a temperature in the range of 130–150 °C, the dried sample is burned. The experimental model is fitted with high accuracy to predict the moisture rate as a function of time. The evaporation processes of SSD are also compared with hot air drying at the same drying conditions. To extend the application ability of the result, the theoretical model is developed on the basis of Fick's law in which the spatial distributions of temperature and moisture are taken into account. The effective diffusivity is determined by an optimization tool with good agreement. This parameter is constant for all drying conditions, so the model can be applied to a huge range of drying conditions. The numerical results show that the temperature is almost uniform in the sample because of high thermal conductivity, but the moisture gradient is significant.

Oxidation and mechanical properties of SiC fibers after high temperature exposure in air and steam

Oxidation and mechanical properties of SiC fibers after high temperature exposure in air and steam

Effect of generator temperature on steam ejector performance in renewable refrigeration cycle considering wet steam model and dry steam model

The rise in global warming has led to an increased utilization of cooling systems. High energy consumption associated with common refrigeration cycles not only contributes to air pollution but also intensifies the consumption of fossil fuels. Consequently, the imperative to conserve energy has become paramount in today's world. One of the methods to decrease energy consumption involves employing systems capable of harnessing waste heat from industries, solar energy, and other sources. The ejector refrigeration cycle (ERC) stands as an example of such systems. In present study, the impact of elevating the generator temperature on various aspects such as flow behavior in the ejector, aerodynamic shocks, entrainment ratio (ER), and entropy production was examined. The investigation encompassed both wet steam model (WSM) and dry steam model (DSM). Based on the findings, it was observed that with an increase in generator temperature, the ER decreases while the production entropy increases. In the WSM, the liquid mass fraction (LMF) also experiences an increase. Additionally, the Mach number distribution in the DSM surpasses that of the WSM and the temperature drop in the DSM is greater compared to the WSM. With the rise in generator temperature from 388 K to 418 K, both the DSM and WSM exhibit a decrease in ER by 52.9% and 58.7%, respectively. Furthermore, the production entropy experiences a substantial increase of 180% and 206% for the DSM and WSM, respectively.

Preparation of Cr2AlC powder and its isothermal oxidation behavior in dry air and pure steam

Preparation of Cr2AlC powder and its isothermal oxidation behavior in dry air and pure steam

Development of Sustainable Dust Compression System for Coal Yard Safety

A sustainable water mist spray system for a closed coal yard. The project aims to address the need for dust suppression in the coal yard to mitigate environmental and health risks. The design specifications will be determined by considering the coal yard's size, layout, and specific requirements. The system will utilize a pneumatic air vane motor powered by residual dry steam from the plant's operation and, coupled with a fan for effective mist dispersion. Ro Reject water, a byproduct of reverse osmosis water treatment, will be used as the water source. The project will involve collaboration with mechanical engineering, fluid dynamics, and environmental studies to develop an optimized system design. Field tests will be conducted to validate the system's functionality, mist spray effectiveness, and coverage area. Safety features will be installed to ensure operator protection, and training programs will be developed to educate operators on safe system operation. The effectiveness of the mist spray system will be evaluated and monitored through regular assessments and data collection. Maintenance activities will be conducted to ensure system functionality, and safety features will be updated as necessary. The successful implementation of this sustainable water mist spray system will contribute to dust suppression, environmental sustainability, and safety in the coal yard.