Dehydration Technology Research Articles

Upcycling to a circular food system

Upcycling to a circular food system

Physical Field-Assisted Osmotic Dehydration Technology and Its Application in Fruit and Vegetable Drying

Osmotic dehydration is a non-thermal processing technology that can promote the dehydration of fruits and vegetables while maintaining their sensory and functional properties and extending the shelf life. However, the main disadvantage of osmotic dehydration technology is the low mass transfer efficiency. Physical field assisted osmotic dehydration technology can effectively improve the efficiency of osmotic dehydration. Physical field assisted osmotic dehydration technology includes ultrasonic, gamma ray, pulsed electric field, vacuum and high hydrostatic pressure assisted osmotic dehydration. Physical field assisted osmotic dehydration technologies and their application in fruits and vegetables are studied in this paper and some new research progresses and the problems are discussed. The mechanism and factors affecting mass transfer efficiency of osmotic dehydration, physical field assisted osmotic dehydration technology, dynamic model and the application of physical field assisted osmotic dehydration in fruit and vegetable drying are discussed.

Energy-efficient sorption-based gas clothes dryer systems

Standard electric resistance and fuel-driven dehydration technologies exhibit a maximum coefficient of performance of well below 1 mainly due to enthalpy losses associated with the air leaving the dehydration system. To improve energy efficiency, condensing dryer systems condense the moisture captured from a product in a closed-loop air circulation cycle. Existing condensing dehydration systems including heat pump dryers, however, need to significantly cool the air to achieve dehumidification. The added cooling and subsequent heating to return the air to a desired drying temperature consume substantial energy and thus reduce drying performance. Here, an innovative sorption-based gas dehydration system is proposed to overcome barriers deteriorating energy efficiency in existing gas, electric, or heat pump dryer systems. Decoupling latent and sensible loads, the system employs a liquid-desiccant solution to directly capture air humidity, thereby allowing circulation of the air in a closed loop to achieve high drying energy efficiency. In other words, the system captures waste latent heat from the moisture produced during the dehydration process and reuses it to improve energy efficiency. This study focuses on a comprehensive quasi-steady-state thermodynamic modeling of the proposed sorption-based dehydration concept employed for a gas clothes dryer application to predict transient response and overall drying performance (i.e., time and energy metrics). The analysis indicates the proposed sorption-based gas clothes dryer system can deliver a specific moisture extraction rate of 1.71 kg of water per kWh (i.e., a combined energy factor of 3.167 kg (6.98 lbm) of dry cloth per kWh) with a drying time of 44 min. This is a 112% energy improvement compared with state-of-the-art gas clothes dryers exhibiting a combined energy factor of 1.50 kg (3.3 lbm) of dry cloth per kWh. The technology pursued here can potentially be employed as a platform for many fuel-driven equipment to take advantage of available waste thermal energy in the environment instead of simply burning a fuel.

The Determination of Water Content in Natural Gas: Aspen Hysys Simulation and P,T Analysis

Natural gas is currently one of the most important fossil fuels in the group of non-renewable energy sources, which is used very widely due to its properties. In order to be able to use it safely, it must be adjusted in accordance with the technical-delivery conditions before use. One of the basic quality parameters of natural gas is the water content, which is set at a maximum value of 110 mg per m3 of natural gas. For this reason, it is necessary to correctly determine the water content before the gas treatment, in order to choose the right dehydration technology. In this article, three methods were used to determine the water content of natural gas.

Experimental study on biological dehydration pretreatment of kitchen waste

Aerobic fermentation treatment technology is one of the effective means of kitchen waste resource treatment at present. Due to the high moisture content of kitchen waste, dehydration pretreatment is needed before aerobic composting.At present, China usually adopts mechanical methods such as forced extrusion for dehydration treatment, which not only has high energy consumption, but also has high content of solid suspended solids (SS) and chemical oxygen demand (COD) in sewage. Sewage is difficult to meet discharge standards.In this paper, biological dehydration technology is proposed to pretreat kitchen waste. Experiments show that biological dehydration pretreatment can dehydrate kitchen waste, effectively reduce the SS and COD values in sewage, which is of great significance to the resource treatment of kitchen waste.

EXPERIMENTAL RESEARCH ON DEHYDRATION OF SOME SPECIES AND VARIETIES OF FRUITS AND VEGETABLES

A good tradition has been formed among Romanians regarding the preservation by drying of some important vegetables and fruits, such as plums, apples, bean pods, mushrooms, carrots, etc. In the peasant households the drying was done naturally, using solar heat, so that the conservation costs were quite low. The transition to the elimination of surplus water from vegetables and fruits by controlled dehydration, in highcapacity technical equipment, has proved beneficial for the possibility of storing and using products thus preserved for long periods, especially in winter and spring, when fresh products are rarer and more expensive even when the human body needs more of their contents. Technologies for preserving plant products by dehydration must be constantly improved in order to increase the quality of products, reduce nutrient losses, increase the safety and efficiency of technical equipment, etc. The experiments aimed at clearly defining the stages of dehydration technologies, with convective dryer, respectively in microwave controlled regime, of some species and varieties of fruits and vegetables, in order to eliminate the chemical processes of inactivation of oxidative enzymes and the application of strict green treatments.

Innovative Infrared Heating Technologies for Food and Agricultural Processing

Food and agricultural industries have an increasing need to develop and adopt novel and sustainable processing technologies with high processing and energy efficiency and less water usage and waste-water generation while, at the same time, delivering safe, high-quality processed food and agricultural products. The use of infrared (IR) radiation heating for food and agricultural processing represents a novel approach for various food thermal processing operations, including drying, blanching, disinfestation, disinfection, and stabilization. Relevant attributes of IR heating technology include high heat delivery rate, lack of need for a heating medium, reduced processing time, improved energy efficiency, and enhanced product quality and safety with a minimal environmental footprint. The author and his research team recently conducted systematic and innovative research on IR heating for food and agricultural product processing, which resulted in an advancement in the scientific knowledge of IR heating in food science and engineering and the development and commercialization of a series of patented processing technologies. The novel IR heating technologies improved food healthfulness, quality, and safety while saving energy and water. The focus of this article is the review of several innovative IR heating-based processing technologies that were developed, including IR dry-peeling, dry-blanching, and dehydration technologies for fruits and vegetables; IR heating technology for drying and roasting of tree nuts; and effective IR heating for simultaneously achieving multiple goals in rice postharvest processing.

Hollow Fibers with Encapsulated Green Amino Acid-Based Ionic Liquids for Dehydration

Dehydration technologies with low energy consumption using non-toxic materials are important in industrial, residential, and transport applications. Herein, nanocomposite polymeric hollow fibers wi...

Application of Integrated Technology of Ecological Dredging and Silt Disposal in Comprehensive River Management

Multi-process such as environmentally friendly cutter suction dredgers are used for river silt cleaning, pipeline pumping, coagulant (PAM) dosing, geotextile tube dehydration and solidification, leachate collection, multi-stage coagulation sedimentation treatment, residual water treatment are adopted to comprehensively control the water quality and silt of the Fu River New District in Anxin County, Xiongan New District. The treated residual water is discharged to Fu River after the test meets the standard, and the silt is solidified and then further comprehensively utilized as resources. Through the design and the whole process of tracking practice in the test phase of this project, the integrated technology of ecological dredging and silt disposal was explored for the construction technology and operation process of river dredging and sediment dehydration and volume reduction, providing reference for standardization and large-scale application of similar projects.

Flue Gas Water Recovery by Indirect Cooling Technology for Large-Scale Applications: A Review

With social development and economic enhancement, energy is facing significant worldwide demand, and fossil fuels are the prime energy sources for various energy systems over past decades. Furthermore, among fuel-consumed applications, power plants are the primary source of energy consumption. There is a lot of waste heat and steam accompanied by the latent heat produced in the exhaust flue gas. Therefore, the latent heat recovery from the flue gas plays an important role in increasing the efficiency of the system and saving water. To recover the heat and mass in power plants, three primary methods are proposed to condense the vapor based on previous studies: (1) flue gas condensation technology, (2) liquid desiccant-based dehydration (LDD) technology and (3) membrane technology. This paper mainly reviews and summaries the indirect cooling technology in flue gas condensation technology. The numerical simulation and theory of flue gas condensation are introduced. Different heat exchanger types and conducted experiments are also summarized. The performance of the indirect cooling technology is affected not only by its own configuration and design but also by the flue gas inlet temperature, velocity, water vapor mass fraction, etc. The major concerns and outlook of practical applications for further study are attributed to the heat exchanger size and cost, acid corrosion, ash accumulation in flue gas, etc.

Application Status and Prospect of Combined Treatment Technology for Oily Sludge in Domestic Oil Fields

The oily sludge has a wide range of sources and complex composition, the corresponding treatment technology and equipment also show a diversified trend, after the combined treatment of oily sludge, the oily sludge can meet the technical requirements of resource utilization and harmless treatment. Through the actual and literature research, the principle, scope, characteristics and development of the commonly used oily sludge treatment methods at home and abroad are summarized, the application status of several new oily sludge combined treatment technologies in China’s petrochemical enterprises is introduced, including sieving fluidization-tempering-mechanical dehydration technology, electrochemical bio-coupling advanced treatment technology, sludge centrifugal dewatering-superheated steam injection treatment technology, hot-washing coupling treatment technology and microbial-plant combined treatment technology, summarized whether the oil content of the residue after treatment by the existing treatment method meets the standard requirements of HJ 607-2011 “Technical Specifications for Pollution Control of Used Mineral Oil Recovery, Recycle and Reuse” and the resource utilization of the residue goes. The problems and treatment effects of the integrated oil sludge treatment technology in application have not yet been treated in a satisfactory manner to completely treat all oily sludge, and further research is needed.

Discussion on dehydration technology of coal mine low-concentration gas reciprocating internal combustion engine

Low concentration gas reciprocating internal combustion engine power generation in coal mine is one of the main ways of gas utilization. This paper aims at the technical problem of low concentration gas power generation efficiency caused by large amount of atomized liquid water carried by gas in low concentration gas pipeline. Based on the analysis of the source of low concentration gas liquid water, this paper discusses in detail research progress of dehydration technology for low concentration gas reciprocating internal combustion engine power generation, and key discusses the mechanical separation method, electric refrigeration method, electric refrigeration combined with cold air circulation method and flue gas residual heat variable temperature method for gas dehydration of low concentration gas power generation.

Effects of conventional and nonconventional drying on the stability of Bifidobacterium animalis subsp. lactis INL1

Freeze, spray, vacuum, microwave vacuum‐ and microwave freeze‐drying were applied to Bifidobacterium animalis subsp. lactis INL1. Freeze and microwave freeze‐drying showed the highest survival after drying. When a storage test (25 °C; oxygen) was performed, these cultures were the most sensitive ones at aw = 0.23, but the addition of lactose improved their stability after 8 weeks. Flow cytometry was useful to assess viability after drying but not during storage. Our results show that dehydration technologies other than freeze‐drying might be suitable alternatives that deserve further investigation for the preservation of sensitive probiotic bacteria. Microwave drying rendered cultures of comparable characteristics to their conventional counterparts, requiring significantly shorter drying times.

Effect of Drying Modes on Quality Characteristics of Dehydrated Green Leafy Vegetables

The present investigation was carried out for justifying the suitability of various dehydration techniques for desired quality of finished products. The commonly consumed green leafy vegetables viz. fenugreek leaves (Trigonella foenumgraecum) and spinach (Spinacia oleracea L.) were assessed for their commercial processing potential through dehydration technology. The selected fresh green leafy vegetables were washed and subjected to steam blanching. The pretreated vegetables were then dehydrated under different drying conditions i.e. sun, shade and tray drying to safe moisture level. The dried samples were evaluated for their dehydration process features, nutritional and sensory characteristics. The data on the dehydration technology revealed that tray dried green leafy vegetables found comparatively more wholesome, palatable and reported maximum retention of nutrients like vitamin C (35–47%), minerals (96%), with minimum drying time (2.30–3.30 hrs) and equilibrium moisture content (6%) as compared to rest of drying methods. The rate constant for drying of fenugreek and spinach leaves were found to be 0.0105 min−1 and 0.0088 min−1, respectively in tray drier. The tray drying method was found comparatively superior in retention of sensory quality parameters (color, texture and overall acceptability) over sun and at par with shade drying.

Changes in the psysical-chemical composition, total polyphenols and antioxidant activity of fresh celery (Apium graveolens L.) dehydrated by hot air and by lyophilization

The food industry aims at offering food that provides not only nutritional but also functional properties. Celery has been used for a long time, but its bioactive compounds have remained unknown. The objective of this research is to measure the changes in the physical and chemical characteristics, total polyphenols (TP) and antioxidant activity (AA) after applying hot air dehydration (DA) and lyophilization (LF) with two different cut types: rod-shaped (R) and sliced (S). It was found that dehydration treatments can enhance some characteristics in celery. When comparing the results, the treatment of (LF-S) presented the best characteristics with less water activity, 46 % of total dietary fiber constituted by 41 % of insoluble fiber and 5 % soluble fiber, 377.69 mg GAE/100g in total polyphenol content and an antioxidant activity of 82.17 μmol TE/100g. These results allow to conclude that celery is a raw material with functional attributes and that it can be industrialized with dehydration technologies, which will enable a long useful life for its bioactive compounds.

Effect of steaming and dehydration on the nutritional quality and functional properties of protein isolates produced from Lablab purpureus (L.) Sweet (hyacinth bean)

The study conducted was focused on investigating the effect of steaming and dehydration on the nutritional quality and functional properties of protein isolates produced from hyacinth bean. This was for obtaining value-added legume-derived protein ingredients for potential food applications. Protein isolates prepared by isoelectric precipitation from legume grains subjected to steaming and dehydration prior to soaking, respectively, displayed traits of high-quality proteins. The major protein polypeptides present among samples were vicilin (7S) and legumin (11S). Steaming was identified useful for producing protein ingredients for nutritional intervention with potential health benefits. Samples recorded improved Fischer's ratio (1.57–1.78), BCAA to tyrosine ratio (3.51–4.28), predicted biological values (44.84–54.70), foaming, and emulsion properties. Dehydration extensively preserved the nutritional qualities and functionality of steamed samples. Findings have the potential to diversify the use of hyacinth bean and help improve the competitiveness of the legume grain sector. Practical applications This study presents how processing strategies (soaking, steaming, and dehydration) may be employed for obtaining legume-derived protein ingredients with improved nutritional quality and functional properties for potential food applications. The underutilization of many indigenous crops is mainly attributed to both limited research and marketing. Thus, research findings could potentially improve the value of hyacinth bean by diversifying its use and help improve the competitiveness of the legume grain sector. This could be achieved through demand for possible food applications that require protein enrichment. Furthermore, results may assist in broadening dehydration technology preferences in existing markets for obtaining legume grain-based ingredients or products with maximum quality.

Cores Produced by Geopolymer Technology and Impact to Casting Quality in Comparison with PUR Cold Box Amin

The article deals with geopolymer binder system for core production, especially by dehydration technology and comparison with PUR cold box amin technology. A sodium-potassium type of geopolymer binder is the subject of the research. The goal of the article is the core production and observing of technological properties, storing cores, usage of refractory coating evaluating of properties during the pouring and decoring of casting. The main target of the experiment is casting quality. It was stated that the final surfaces are much more better than PUR cold box amin technology and the internal casting quality is the same, it means without inadmissible internal defects. Worse decoring times were observed. It has been confirmed, that neither emissions, fumes nor unpleasant odours are generated during the production procedure nor during pouring.

Primary dehydration of peat on floating mining platforms

The use of peat as a local type of fuel is advisable for many remote areas of our country. Improving the efficiency of peat resources makes it possible to ensure energy security of the country and reduce emissions to the atmosphere, as compared to the use of hydrocarbon energy sources. Autonomous floating platforms utilized for peat extraction and further treatment call for a scientifically sound selection of their parameters, which is specified by the equipment and dehydration technology applicable for the extracted raw peat materials. A study of filtration properties and chemical composition of impurities in aqueous solutions or peat pulps enables a rational approach to water separation and improvement through a short-term magnetic exposure. The identified outputs form the cornerstone of innovative technologies for primary peat dehydration.

CO<sub>2</sub> Rich Natural Gas Processing: Technical, Power Consumption and Emission Comparisons of Conventional and Supersonic Technologies

Supersonic separator is investigated via process simulation for treating CO2 rich (>40%) natural gas in terms of dew-points adjustment and CO2 removal for enhanced oil recovery. These applications are compared in terms of technical and energetic performances with conventional technologies, also comparing CO2 emissions by power generation. The context is that of an offshore platform to treat raw gas with 45%mol of CO2, producing a lean gas stream with maximum CO2 composition of ≈20%mol, suitable for use as fuel gas, and a CO2 rich stream that is compressed and injected to the oil and gas fields. The conventional process comprises dehydration by chemical absorption in TEG, Joule-Thomson expansion for C3+ removal, and membrane permeation for CO2 capture. The other alternatives use supersonic separation for dew-points adjustment, and membranes or another supersonic separation unit for CO2 capture. Simulations are carried out in HYSYS 8.8, where membranes and supersonic separation are modeled via unit operation extensions developed in a previous work: MP-UOE and SS-UOE. A full technical and power consumption analysis is performed for comparison of the three cases. The results show that the replacement of conventional dehydration technology by supersonic separators decreases power demand by 8.5%, consequently reducing 69.66 t/d of CO2 emitted to the atmosphere. The use of supersonic separation for CO2 capture is also superior than membranes, mainly due to the production of a high-pressure CO2 stream, that requires much less power for injection compression than the low-pressure permeate stream from membranes. Therefore, the case with two supersonic separator units in series presents the best results: lowest power demand (-23.9% than conventional case), directly impacting on CO2 emissions, which are reduced by 2598 t/d (-27.82%).

Experimental study on the dehydration performance of synergistic effect of electric field and magnetic field

Electromagnetic synergistic oil-water separation is a promising technology for deep dehydration with higher efficiency, shorter dehydration period and flexible control of field parameters. In this paper, non-conductive silicone oil without colloid and asphaltene was used as the continuous phase. The effect of magnetization and Lorentz force on the continuous phase can be excluded to explore the mechanism of the electric field and magnetic field synergistic dehydration. Firstly, the particle size of droplets was characterized. The results showed that the dispersed phase was uniformly distributed and the average particle size was 18.24 um. Then the dehydration performance of different types of outfields was compared. The experimental results showed that the dehydration performance of AC electric field combined with magnetic field was better than that of single AC electric field. The dehydration performance of AC electric field and magnetic field was better than that of DC electric field and magnetic field. On this basis, the theory of AC polarization-electromagnetic force was proposed. Finally, the influence of magnetic field intensity on dehydration performance was explored, including dehydration depth and dehydration speed, and the optimal magnetic field intensity range in this experiment was obtained, and its value was [0.269, 0.355] T.