Superheated Steam Research Articles

How superheated steam treatment modifies the physicochemical, functional, nutritional, and anti-nutritional attributes: A case study on guar bean flour

Guar seed flour (GSF) is a nutritionally rich ingredient that is widely available, but antinutritional factors limit its commercial use. Considering this limitation, the present study investigated the effect of superheated steam (SHS) treatment (120–150 °C, 5–15 min) on the nutritional properties, bioactive compounds, anti-nutritional factors, thermo-pasting and structural characteristics, and in-vitro digestibility of GSF. The SHS treatment influenced the carbohydrate, protein, and fat content and improved the functional properties of GSF. Similarly, an increment in total phenolic content, antioxidant activity, and a decline in total flavonoid content was observed. The maximum reduction of tannin, phytic acid, and saponin was observed in GSF samples treated at 150 °C – 15 min. The diffractogram pattern showed a decrease in crystallinity with increasing SHS temperature and duration, trypsin inhibitor activity was reduced, while the in-vitro digestibility increased. Apart from this, the SHS treatment also influenced the thermo-pasting properties of GSF, which might be due to the intermolecular interactions, cross-linking, and starch-lipid interactions. Industrial relevanceThe SHS treatment provides high energy efficiency and has the potential to be commercialized on an industrial scale in the food industry, despite its popularity in the non-food sector. The findings indicate that SHS treatment under optimal conditions improved GSF's physicochemical, functional, and digestibility properties. Furthermore, the SHS treatment was very effective at reducing anti-nutritional factors. The product developed from SHS-treated GSF has the potential to be a viable alternative for food formulations and will have a positive impact on human health.

Performance degradation analysis of a medium pressure superheater due to tube deactivation

Steam is essential in petrochemical industries for the transportation of thermal energy and usage in some reforming process. Superheaters are heat exchangers that convert saturated steam to dry steam by utilizing waste heat from the flue gas stream. Medium pressure steam superheaters are prone to tube deterioration due to service at elevated temperatures and erosion from the presence of liquid phase in the steam, leading to tube plugging after tube failure. This reduces the overall surface heating area of the superheater. Relations between the tube plugging practice and the energy dynamics of the superheaters are important for engineers to identify the responses of the superheater for operation planning, and this issue has not been extensively explored academically. This article analyses the deterioration of superheater performance due to reduction of surface heating area based on operational data of a petrochemical steam generation line. The objective is to find relations between the effect of tube plugging on the states of both steam and flue gas streams, as well as its impact on the overall energy exchange. The operating conditions of a superheater at two separate service years, before (year 2014) and after (year 2017) tube plugging, were compared through the first law energy analysis. The average steam inlet temperatures were between 248 °C and 250 °C, at flow rates between 70 and 90 ton/hour. The analysis indicated that 0.3 to 0.8 % increase in inlet energy is required for every plugged tube to compensate for the reduction of heating surface. At 3 % reduction of heating surface area, the heat exchanger effectiveness decreases by an average of 11 % that also leads to a lower steam temperature output by approximately 6% from the design operating temperature. These results would assist steam engineers to analyse changes to the energy economics of the whole plant and decide the feasibility of replacing existing superheaters with new ones. Also, another significant finding to be considered by steam engineers is that the current practice of increasing the steam flow rate does not offset the loss of energy effectiveness due to tube plugging.

Steam Generator for Hydrothermal Treatment of Agricultural Equipment

The paper highlights the importance of keeping the working surfaces of agricultural machinery clean and describes the existing modern equipment for its cleaning. (Research purpose) To develop a biofuel system for cleaning machines, equipment and tools in the field. It is proposed to apply a mobile steam generator using wood, chocks, straw and other agricultural waste as a fuel and capable of providing pressure of 5 kilograms per square centimeter and a temperature of 150 degrees Celsius. (Materials and methods) The paper describes the algorithm of the steam generator operation and presents its main technical characteristics and the design diagram. Theoretical calculations of the air consumption for the constant and adjustable air supply systems are provided. (Results and discussion) It has been established that one load of 8 kilograms of biofuel and 6 liters of water ensures 20-25 minutes of intense steam production. The steam generator was equipped with two systems for supplying air to the furnace, a safety valve for dumping steam at excess pressure. The boiler has a built-in superheater that ensures the necessary steam characteristics at the boiler outlet. (Conclusions) The developed steam generator reveals the following advantages: mobility, use of biofuel, a 20-25 minutes continuous supply of superheated steam at one load. The new unit is designed for long-term operation and it is capable of not only defrosting and cleaning a frozen manure conveyor, a manure trolley, a spreader, and loader working bodies, but also warming up larger agricultural machinery. It is also suitable for sanitizing seed harvesting and livestock equipment in the field.

Assessment of the Porous Structure and Surface Chemistry of Activated Biocarbons Used for Methylene Blue Adsorption.

In the presented research, activated carbons from wheat bran were obtained as a result of pyrolysis and physical activation (CO2 or/and steam). In addition, the obtained materials were subjected to additional modification with superheated steam using the microwave radiation as an energy source. The detailed materials characterization was performed using low-temperature nitrogen adsorption/desorption, Raman spectroscopy, X-ray diffraction, thermal analysis (TG), Boehm's titration, point of zero charge (pHpzc), scanning electron microscopy (SEM) and FT-IR/ATR methods. Moreover, the sorption capacity towards methylene blue (MB) was determined. The activated carbons were characterized with a well-developed surface and pore structure (SBET = 339.6-594.0 m2/g; Vp = 0.157-0.356 cm3/g). Activation in the presence of steam and additional modification with microwave radiation resulted in much better development of the porous structure (SBET = 600.4 m2/g; Vp = 0.380 cm3/g). The materials were shown to possess amorphous structure and thermal stability up to the temperatures of ~450-500 °C. They have good adsorption capacity towards MB varying from 150 mg/g to 241 mg/g depending on activation manner. The adsorption can be described by the pseudo-second order model (R2 = 0.99) and fitted to the Langmuir isotherm.

Slight carbonization as a new approach to obtain peat alternative

Biochar has been widely studied to replace peat in growing media due to its suitable water holding capacity, non-phytotoxicity, stability, and some nutrients. Those features are most probably generated during biomass carbonization, because raw garden waste, common feedstock for biochar, generally has plant originated phytotoxic compounds and unbefitting pH, EC and poor water holding capacity as growing media. However, most studied biochar (pyro-char/hydro-char/torrefied-char) are deeply carbonized biomass resulting in other features, e.g., rich nanopores and/or severely degraded cellulose and lignin. Those features are less found in the conventional growing media, i.e., peat. Therefore, we assume that slightly carbonized products with properties between biochar and raw garden waste might perform as peat alternatives. Superheated steam (SHS) torrefaction is a recently proposed incomplete carbonization process, which could selectively boost biomass decomposition and regulate features favoring growing media. Temperature and residence time parameters were investigated to customize product properties to remove phytotoxicity compounds, increase water holding capacity, prolong half-life, and obtain proper pH and EC. After evaluating the properties of products, an optimized product generated in 5 min at 350 ℃ was selected. Hemicellulose and extractives have been extensively removed by 99.6% and 90.2%, respectively. The product had a pH of 6.81, EC of 344 µs/cm, water holding capacity of 0.507, germination index of 96.54% and half-life of longer than 100 years. Therefore, the product was investigated to replace peat as growing media at different rates with three horticultural plants and evaluated by dry weight, plant height, SPAD value, nitrogen content, and the number of flowers. The optimized products could replace up to 40 vol% peat and benefit plant growth.

Studying the benefits of liquid hydrocarbon combustion in a high-velocity jet of superheated steam when compared with other atomizers: CO2 and air

Studying the benefits of liquid hydrocarbon combustion in a high-velocity jet of superheated steam when compared with other atomizers: CO2 and air

Анализ и оценка пожаровзрывобезопасности блочно-модульной котельной, использующей альтернативный теплоноситель

Currently, boiler installations, in which high-temperature mineral or synthetic oil is used as a coolant, are an alternative to industrial steam boilers with superheated steam as a source of process heat. The advantages of the technological and economic nature of the introduction of block-modular boilers into the energy industry with the use of alternative working bodies should be combined with the solution of issues of ensuring their safe operation. The article ranks technological advantages, as well as hazards by the type of coolant used in the thermal oil, steam, and hot water boilers. Difficulties in calculating the category of boiler room premises for explosion and fire hazards are associated with the lack of reliable data on the physico-chemical properties of diathermic oil. Calculations of the most important characteristics influencing the choice of the category of premises for explosion and fire hazard are presented, the factors influencing the fire and explosion safety of the boiler house by oil are identified. It is shown that the safety level of a thermal oil block-modular gas boiler house, tested for emergency oil spills, corresponds to the fire and explosion hazard category B or B3. Calculation of the category of the room of the thermal oil boiler room for explosion and fire hazard in case of emergency gas leaks showed that the boiler room should be attributed to the most hazardous category of explosion and fire A. When calculating the explosion and fire hazard category of the thermal oil gas boiler room, it is determined by gas.

Solar-assisted gasification of agriculture residues for green hydrogen production

The present study proposes a novel way of green hydrogen (H2) synthesis by steam – air biomass gasification assisted by solar energy. In view of environmental problems arising due to stubble burning of agricultural residues in India, bagasse, rice straw and wheat straw are selected as biomass samples. Biomass gasification process is simulated in ASPEN Plus software and then effects of gasification temperature (Tg), equivalence ratio (ER) and steam – to – air mass ratio (S/A) on molar H2 content of producer gas (MHC), higher heating value of producer gas (HHV) and cold gas efficiency (CGE) are studied. The process is optimized using Response Surface Methodology (RSM). It is found that Tg=800 °C – 900 °C, ER=0.2 and S/A=1.8–2.2 are optimum ranges to maximize MHC, HHV and CGE, yielding about 40 % MHC, 6 MJ/kg HHV with 80 % CGE. At optimum operational conditions, steam required for steam-air gasification of a 15 kWth gasifier is calculated. This steam is superheated by solar tower. Total heliostat area requirement is calculated to be 40 m2–65 m2 for different input temperatures of superheated steam (Ts) during steam-air gasification.

Superheated steam cooking improved meat quality: evidenced by water status and protein degradation

Superheated steam cooking improved meat quality: evidenced by water status and protein degradation

Influence of superheated steam treatment on physicochemical, edible, and storage characteristics of highland barley grains

AbstractBackground and ObjectivesThe effects of superheated steam (SS) processing conditions on physicochemical properties and edible qualities of highland barley (HB) grains are still not clear enough. The storage stability of SS treated HB grains is also need to be verified through long‐term storage. Effects of SS treatment on physicochemical, edible and storage properties of HB grains were investigated.FindingsSS processing significantly reduced peroxides and polyphenol oxidase activities. Pasting properties showed that SS treatment resulted in significant increase of viscosity parameters. With improved hardness, gumminess, chewiness, and decreased cooking loss, the cooking and textural qualities were improved by SS processing. Storage properties showed that SS processing inhibited the increase of free fatty acid value, peroxide value and carbonyl value during storage, indicating that the oxidative rancidity of HB grains was retarded. SS treatment also maintained the water hydration properties, pasting properties, and textural properties during 6 months of storage.ConclusionsSS treatment significantly improved the edible and storage properties of HB grains.

Multi-objective optimization of the effects of superheat degree and blade pitch on the wet steam parameters

Steam expansion in the low-pressure stages of the steam turbines, due to the supercooled flow, causes the nucleation phenomenon and the two-phase flow, which leads to an efficiency drop and severe mechanical damage to the turbine. In this research, the impacts of the inlet steam superheat degree and variation of blade pitch in the turbine blade cascade have been investigated. Then, optimizing the concurrent effects of the inlet steam superheat degree and blade pitch to keep the inlet mass flow rate fixed are studied utilizing the genetic algorithm. Moreover, wetness fraction, pressure losses, momentum, and economic cost are the objective functions of the present study. Based on the results, as the inlet steam superheat degree increases, the inlet mass flow rate of the turbine blade decreases; and the blade pitch increase can increase the mass flow rate. Case B is chosen as the optimal case in which, when the inlet mass flow rate is fixed compared to the original case, the wetness fraction, the droplet average radius, and the pressure losses decrease by 56%, 65%, and 3.4%, respectively, and the momentum increases by 5%; in addition, the economic cost is 1.5 ($/hour) in the optimal case.

Computational modeling of spatial variation in moisture content and temperature distribution in corn at different superheated steam temperatures

The Superheated steam has been shown to be more effective than hot air for drying corn. Modeling studies have been carried out in fluidized bed dryers to determine the moisture and heat transfer characteristics of corn, but there are no modeling studies for a single corn kernel. Knowledge of heat and mass transfer characteristics in a single kernel would produce a better understanding of steam characteristics needed for specific drying rates. The study sought to determine the influence of steam temperature and velocity on the drying rate of a corn kernel. It used computational fluid dynamics (CFD) to model the transfer of heat and moisture between the corn kernel and superheated steam. The simulation used cone geometry to represent the corn kernel. The kernel had characteristic dimensions and 20% initial moisture content. The condition of the steam, which was typical of that found in industry, had temperatures of 120–200°C and velocities of 0.5–1.5 m/s. There was a decrease in the duration of the initial condensation phase as the temperature of superheated steam increased from 120°C to 200°C. The highest steam temperature and velocity resulted in the shortest duration for steam condensation. Contrary to what has been reported, there was no moisture loss from the corn kernel when exposed to superheated steam at 120°C, which may be due to how heat was retained in the drying chamber. Thus, the processes of tapping steam and retaining heat are important elements in the operation of industrial steam driers.

Evaluation of Chinese Prickly Ash and Cinnamon to Mitigate Heterocyclic Aromatic Amines in Superheated Steam-Light Wave Roasted Lamb Meat Patties Using QuEChERS Method Coupled with UPLC-MS/MS

Chinese prickly ash and cinnamon contain many antioxidants, which scavenge free radicals and can reduce many harmful compounds, such as heterocyclic aromatic amines (HAAs). Modern technologies used for cooking, such as the use of superheated steam roasting, are beneficial in decreasing the development of HAAs. The current study was based on the use of these two spices in roasted lamb patties to mitigate the formation of HAAs in superheated steam roasted patties. Results exhibited significant differences (p < 0.05) in the content of both polar and non-polar HAAs as compared to control patties. In cinnamon roasted patties, polar HAAs were reduced from 23.76 to 10.56 ng g−1, and non-polar HAAs were reduced from 21.34 to 15.47 ng g−1. In Chinese prickly ash patties, polar and non-polar HAAs were 43.60 ng g−1 and 35.74 ng g−1, respectively. Similarly, cinnamon-treated patties showed a significantly higher (p < 0.05) reduction in polar HAAs (23.52 to 12.41 ng g−1) than non-polar (16.08 to 9.51 ng g−1) at concentrations of 0.5–1.5%, respectively, as compared to the control, with 45.81 ng g−1 polar and 35.09 ng g−1 non-polar HAAs. The polar HAAs tested were PhIP, DMIP, IQx, and 8-MeIQx, while the non-polar were harman and norharman. Both spices and superheated steam controlled HAAs to a significant level in lamb meat patties.

Characterization and corrosion behavior of plasma electrolytic oxidation coating on zirconium alloy in superheated steam condition

The plasma electrolytic oxidation (PEO) coating on Zirconium (Zr) alloy was employed and immersed under 400 °C/10.3 MPa steam conditions. The surface morphology, phase composition, microstructure, and element distribution of the PEO coating after corrosion were analyzed. The results indicate that the PEO coating presents lower corrosion weight gain because the compact oxide layer on the PEO coating presents few cracks and prevents the corrosion media from entering the substrate. The compact oxide layer is caused by the high compressive stress in PEO coating, which is helpful for the nucleation of t-ZrO2 grain and restricting the phase transformation from t-ZrO2 to m-ZrO2, thus reducing the volume expansion and defects. Based on the XRD, SEM, XPS, Raman mapping, and TEM results, the corrosion mechanism and phase transformation processes of the PEO coating under 400 °C/10.3 MPa conditions were summarized.

Nonlinear operational optimization of an industrial power-to-heat system with a high temperature heat pump, a thermal energy storage and wind energy

The heat demand for industrial processes is often provided in the form of steam generated by various fossil fueled equipment. In order to reduce CO2 emissions, the heat demand has to be covered by renewable energy sources. Electrified steam generation relies on complex energy systems, that can be operated according to energy availability and cost developments. However, such a multi component industrial energy system poses a challenge in modeling and determining the cost- or emission-optimal operation of the system. This study develops a methodology to model a multi component industrial energy system on the basis of a case study. By optimal system operation, either costs or emissions are minimized in response to fluctuating renewable wind energy and electricity prices.A high temperature heat pump (HTHP), a sensible thermal energy storage (TES) and a wind turbine are combined to create an electrified energy system to supply super-heated steam. During periods of low wind speed, additional grid electricity is purchased to ensure a steady heat supply. The HTHP offers a high operational flexibility and thus, enables the charging and discharging of the TES. A model of the closed reverse Brayton cycle HTHP, which is able to simulate part load behavior, is created in a process simulation software and consolidated in nonlinear surrogate models. The component behavior of a TES is represented by a combination of equations based on heat exchanger relations. Finally, the resulting algebraic nonconvex, nonlinear optimization problem based on the proposed system is solved using the local interior point optimizer (IPOPT) solver equipped with a multi-start approach to determine an optimal operation over a reference week with respect to the current wind power generation, grid emissions and electricity prices.The results of the optimization show, that optimal operating strategies enable a high potential to decarbonize future industries at minimum operational costs or emissions.

Chemical composition, antioxidant, and antimicrobial activities of P. roxburghii oleoresin essential oils extracted by steam distillation, superheated steam, and supercritical fluid CO2 extraction.

Pinus roxburghii is a rich source of high-quality oleoresin that is composed of resin acids and essential oil (EO). The present research work was planned to study and compare the yield, biological activities, and chemical profiling of P. roxburghii oleoresin EOs extracted through various green extraction methods. Steam distillation (SD), supercritical fluid extraction, and superheated SD (SHSD) at different temperatures (120, 140, and 160°C) were employed to extract EOs from P. roxburghii oleoresin. Antioxidant potential of EOs was determined by total antioxidant content/ferric-reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging activity (DPPH-FRSA), hydrogen peroxide scavenging assays, and percentage inhibition in linoleic acid. Antimicrobial activity of EOs was determined by resazurin microtiter-plate, disc diffusion, and micro-dilution broth susceptibility assays. Gas chromatography-mass spectrometry was used to determine the chemical composition of EOs. It was observed that extraction methods significantly affected the yield, biological activities, and chemical composition of EOs. The maximum yield (19.92%) was found in EO extracted by SHSD at 160°C. EO extracted by SHSD at 120°C showed the highest DPPH-FRSA (63.33%±0.47%), linoleic acid oxidation inhibition (96.55%±1.71%), hydrogen peroxide scavenging activity (59.42%±0.32%), and total antioxidant contents/FRAP (134.49%±1.34mg/L of gallic acid equivalent). The antimicrobial activity results showed that superheated steam-extracted EO of 120°C revealed the highest antifungal and antibacterial activity. It is concluded that SHSD is an alternative and effective technique for the extraction of oleoresins EO that improves the EO yield and biological activities. Further research on optimization and experimental parameters for the extraction of P. roxburghii oleoresin EO by SHSD is required.

Optimization of Efficient Development Modes of Offshore Heavy Oil and Development Planning of Potential Reserves in China

Thermal recovery is still the most important means to increase heavy oil EOR. With the increase in the recovery factor and the difficulty of exploiting new exploration reserves, the efficient utilization of offshore heavy oil reserves has attracted much attention. However, due to the challenges of high development investments, high operating costs, platform safety factors, and high economic cumulative yield, the offshore heavy oil reserves of nearly 700 million tons have not been effectively utilized. In this paper, Chinese offshore heavy oil reserves were taken as the research object. The indoor one-dimensional experiments were carried out to optimize an applicable development method, and the superheated steam huff and puff was selected as the injection medium for high-speed and high-efficiency development of offshore heavy oil, which verified the great potential of the application of superheated steam in offshore heavy oil thermal recovery. A numerical simulation model for offshore heavy oil superheated steam injection development was established, and a dynamic model considering the thermal cracking of heavy oil was established through historical matching. Through the field numerical simulation models, the whole process development mode of a single sand body, thin interbedded reservoir superheated steam huff and puff turning to superheated steam flooding, and thick layer super heavy oil reservoir with bottom water sidetracking after superheated steam huff and puff for eight cycles was established. Through the numerical simulation method and grey correlation method, the main control factors of superheated steam development of different types of heavy oil reservoirs were determined, and the cumulative oil production charts of different types of reservoirs under the influence of the main control factors were built. The economic evaluation model of superheated steam development of offshore heavy oil was established. Combining multi-specialty of geological, reservoir engineering, drilling and completion, oceanographic engineering, economics, the economic limits of steam injection development under different reserve scales, and engineering conditions of offshore heavy oilfields were clarified. At last, we planned the economic production mode of undeveloped reserves and predicted the construction profile of superheated steam capacity of offshore heavy oil using the production charts and the economic charts. The research results clarify the great potential of thermal recovery development of offshore heavy oil, provide an important basis for the economic development of offshore heavy oil undeveloped reserves, and also provide an important decision for the sustainable and stable production of global heavy oil reservoirs.

Numerical Simulation of Superheated Steam Flow and Heat Transfer in a Balanced Steam Injection Flow Control Device

Dual-string steam injection pipe is widely used in the production of superheated steam injection in heavy oil horizontal wells. Due to the nonuniform steam injection volume at the heel end and the existence of an interlayer and other factors in the reservoir, the distribution of steam cavity is not uniform, so it is necessary to control the flow of the steam injection well. Based on the basic principles of fluid mechanics and heat transfer, a three-phase nozzle outflow control device model is established in this paper. The steam flow and heat transfer law in the flow control device is numerically simulated, and the outflow dynamic law of horizontal well OCD completion in heavy oil reservoir is obtained. On this basis, the influence of OCD aperture parameters, steam injection pressure, and steam injection velocity on OCD throttling effect is studied. The results show that OCD has a good control effect on balancing pressure drop and improving steam injection uniformity. When the throttle aperture occupies 1/3 of the pipe diameter, the throttle effect is the best and the heat loss is low. Increasing the steam injection pressure can rapidly enhance the pressure reduction rate of the throttle hole. The throttling effect of increasing steam injection volume is not obvious, and the energy loss becomes higher. The study of this paper provides a reference for parameter optimization and prediction of steam distribution in the flow control device of horizontal wells.

Effects of Blanching Methods on Nutritional Properties and Physicochemical Characteristics of Hot-Air Dried Edible Insect Larvae.

Global meat consumption is increasing worldwide, however, supply remains lacking. Several alternative protein sources, such as cultured meat, plant-based protein production, and edible insects, have been proposed to overcome this shortage. Interestingly, edible insects are characterized by superior digestive and absorptive qualities that make them the ideal replacement for traditional protein production. This study aims to further the processing ability of insect protein by investigating the effects of various pre-treatment methods, such as blanching (HB), roasting (HR), and superheated steam (HS), on the nutritional properties and physicochemical characteristics of proteins extracted from Hermetia illucens larvae. The drying rate, pH value, color analysis, amino and fatty acid profile, as well as bulk density, shear force, and rehydration ratios of the above pre-treatment methods, were explored. HS was found to have the highest drying rate and pH value analysis showed that HB and HS samples have significantly higher values compared to the other modalities. Raw edible insects had the highest value in the sum of essential amino acid (EAA) and EAA index when compared to EAAs. HB and HS showed significantly lower bulk density results, and HS showed the highest shear force and the highest value in rehydration ratio, regardless of immersion time. Therefore, taking the above results together, it was found that blanching and superheated steam blanching pre-treatment were the most effective methods to improve the processing properties of H. illucens after hot-air drying.

Recovery of carbon fibers from carbon fiber-reinforced epoxy-isophorone diamine composites via step thermolysis

Thermosetting composites are widely used in various industries owing to their excellent mechanical properties, dimensional stability, and convenient formability. However, once cured with epoxy resin, the separation of thermosetting composites from carbon fibers is challenging. Industrial waste resulting from end-of-service-life carbon fiber-reinforced thermosetting plastic (CFRP) is a significant environmental problem. Thus, eco-friendly and economic processes must be developed to increase resource efficiency by converting waste CFRP into reusable materials. This study aims to find the optimal conditions for the recovery of recycled carbon fiber (r-CF) from thermoset CFRP manufactured using epoxy (EP) and isophorone diamine (IPDA). A multi-step thermolysis method using superheated steam and air was proposed. We confirmed that an oxidizing atmosphere is required to recover clean r-CF without char. The mechanical strength of the recovered r-CF was dependent on the pyrolysis temperature and time, which was due to an increase in defects from the oxidative decomposition of the r-CF surface. Finally, the recovery rate was 95%, and the tensile strength of the recycled carbon fiber was 80% higher than that of virgin carbon fiber.