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The paper drying process has the highest level of energy consumption in the pulp and paper production process. Analysis and optimization of the energy system during the paper drying process is critical for improving the energy efficiency of the entire paper mill. In the existing model for the paper drying process, the solution requires accurate boundary conditions such as the air temperature and humidity of the pocket area and the cylinder surface temperature, which are very difficult to obtain in the papermaking process. This can result in significant deviations between the model solution and the actual production process. This paper focuses on the single-tier dryer cylinder-based paper drying process that has been widely used with high-speed papermaking machines in recent years. A mathematical model is proposed based on real-time data. The verification via industrial production demonstrates that the proposed model is reliable for the paper drying process. Based on the simulation results, two optimization operations have been proposed. The energy consumption decreases from 1.51 t steam/t paper to 1.44 t steam/t paper, 4.6% of the steam and 1.26 × 106 RMB can be saved for a medium-scale paper mill with the annual production capacity of 105 t paper.

The drying performance of multicylinder dryer section in a paper machine was investigated under various operating parameters: Inlet paper solid content (48–50%), inlet paper temperature (45–50°C), supply air temperature (100–90°C), and exhaust air humidity (75–85 g H2O/kg dry air). The variation in environmental conditions was also considered. In this study, an improved static model was utilized to study the influence of these operating parameters on paper drying. The model was constructed using sequential modeling approach based on the drying techniques of multicylinder dryer section of a paper machine. The calculated paper solid content leaving each paper drying module and energy use is in agreement with the measured results. The simulation results showed that higher paper solid content and temperature entering the dryer section, lower supply air temperature, and higher exhaust air humidity were favorable for drying performance within the studied range of these parameters.

A custom experimental apparatus is designed to perform through air drying under well-controlled drying conditions such as air temperature and mass-flowrate. Using a novel optical measurement technique, the spatial distribution of moisture content in paper during through air drying is quantified as a function of time. The technique is capable of measuring the moisture content distribution with high spatiotemporal resolution while air flows through a paper mat sitting on a permeable dryer fabric. Four commercially available fabrics with different structural design and properties are used in the investigations. The effect of the fabrics’ structural properties, which are characterized using optical coherence tomography (OCT), is studied under various drying conditions. It is shown that the geometry of the contact spots of the fabrics has a significant impact on the drying time at high drying intensities. However, at low rates of drying (i.e., low air temperature and flowrate), no correlation between d...

Heat Recovery Ventilator (VHR) is widely used nowadays as it is capable to maintain high Indoor Air Quality (IAQ) while minimizing the energy loss of indoor air through air-to-air heat exchanger principle. The main component that enables VHR to perform air-to-air heat exchange is known as Paper Heat Exchanger (PP-HEX). Hence, the objective of this research is to study and analyse the performance of a PP-HEX under different return and outdoor air temperatures as well as their effect on both enthalpy and temperature exchange efficiency. Moreover, some numerical models of VHR have been developed to optimize some complex cases and the numerical models are meant to reduce the physical experiments to analyze or improve complex cases in the future. To the best of the authors knowledge, there is no experimental data available from any sources to validate the numerical models. To address this issue, two different supplies of PP-HEX are tested with an actual VHR, and both PP-HEXs will be referred to as PP-HEX-A and PP-HEX-B due to confidentiality. Furthermore, the testing is conducted in a temperature-controlled testing laboratory and the testing conditions are set according to the ISO standard. The preliminary testing results show that the temperature exchange efficiency and enthalpy exchange efficiency of the PP-HEXs have the same trends while the outdoor air temperature is fixed and varying the temperature of indoor air. In contrary, the temperature exchange efficiency and enthalpy exchange efficiency of the PP-HEXs have the same trends while the indoor air temperature is fixed and varying the temperature of outdoor air as well. With the default voltage supplies (240V) to VHR and the setup conditions (according to the ISO Standard) of return air to be 27°C and outdoor air to be 35°C, the testing results show that PP-HEX-A has a temperature exchange efficiency and enthalpy exchange efficiency with a range of (37.97 – 40.28) % and (30.77 – 57.81) % respectively. While PP-HEX-B has a temperature exchange efficiency and enthalpy exchange efficiency with a range of (35.29 – 42.5) % and (39.6 – 55.93) % respectively.

One of the most problems for achieving thermal comfort in buildings is disregarding the impact of different types of building use. They are differ depending on the activity style they perform inside. In residential buildings, for instance, variations in indoor temperature is more acceptable than the case in hotels or hospitals. This review is leading to seek a solution for this problem which usually found neglected. Consequently, the selection of the reviewed papers was based on building use. Main factors affecting thermal comfort will be discussed. In addition, focus on the effect of building's function on thermal comfort such as residential buildings, office buildings, heath care buildings and educational buildings. As far as environmental aspects affecting thermal comfort, air temperature was found to be the most effective one among the rest. Moreover, the effect of building function on adaptive thermal comfort has been discussed with reference to residential, office, healthcare and educational buildings. It has to be considered that there is a noticeable effect on the different types of building in terms of its impact on the users.

Desiccant materials are recently discovered as a viable alternative in dehumidification technology due to their naturally hygroscopic qualities and minimal energy requirement. This paper discusses the performance of four brand samples of selected desiccants used for dehumidification. In this study, dehumidification ability and indoor air quality (IAQ) tests were carried out. The dehumidification ability test was conducted in a controlled environmental chamber at a temperature of 25°C, relative humidity of 70%, and air velocity of 2 m/s for 45-minute session. Meanwhile, the IAQ test was carried out in a naturally ventilated test room, and six IAQ parameters (relative humidity, air velocity, air temperature, particulate matter (PM10), airborne bacteria and carbon dioxide (CO2) were studied. The IAQ test was performed for five different conditions: control, application of brand samples A, B, C and D in the test room. From this study, it was found, brand A (0.6823 g/kg) and brand B (0.6849 g/kg) had a relatively good dehumidification ability during the 45-minute dehumidification ability test compared to brand C (0.3108 g/kg) and brand D (0.3982 g/kg). The IAQ test revealed that brand A had the biggest variation in indoor-outdoor relative humidity of 13.12%, while brand D had the smallest difference of 11.83%. Brand B had the highest average PM10 concentration of 0.037 μg/m3. The airborne bacterial count for all conditions had no statistical significance, indicating the application of desiccants were not effective in reducing airborne bacteria. From this study, it can be concluded that calcium chloride (brand A and B) samples performed better than silica gel (brand C and D) samples in terms of dehumidification ability and IAQ profile.

Liquid smoke increased in demand by the community because it is made from environmentally friendly waste can directly reduce environmental pollution. The smoke condensing process that is carried out conventionally using water can be continuously replaced using a refrigeration system, the smoke condensation process can be carried out using controlled low-temperature air, this can minimize machine space and energy. In this study, an analysis of variations in air temperature will be carried out to maximize the productivity of liquid smoke. The raw material for palm kernel shell is -4 + 5 mesh with cabin temperature variations of 10-15°C, 5-10°C, and 0-5°C and pyrolysis temperature of 300-400°C. Based on the research results obtained maximum results at a temperature of 0-5°C with 23.6% liquid smoke, 3.7% tar, 63.8% charcoal, and 8.9% gas. The test results of chemical compounds, liquid smoke has an average phenol value of 56.59%. The lower the air temperature used to condense the smoke, the maximum liquid smoke will be and the less gas escapes to the air. It can directly reduce air pollution in the process of making liquid smoke.

This article performed various analysis on Red chilli by hybrid collector with solar dryer (HCSD). This study was carried out forced convection solar dryer which performed better in all aspects such as drying time, moisture removal rate, electrical efficiency, electrical thermal efficiency, thermal efficiency and overall thermal efficiency. In general, solar radiation was provided a sources of generating energy to drive a solar dryer. Hybrid collector has been provided the electrical and thermal energy to run a solar dryer. The solar dryer was tested by drying 12 kg of red chilli in the drying air temperature in the range of 32 0C – 56 0C. The initial moisture content of the red chilli was 71.5 % (weight basis) and was reduced to the final moisture content of 16.2 % (weight basis) in 6 consistent days with clear sunny days. The HCSD was operated between 9 hrs to 16 hrs. Finally, comparative study was also handled for better understanding in HCSD, in which solar dryer drying made better outcome than open sun drying.

A prototype hybrid Photovoltaic Thermal (PV – T) solar dryer aided with Evacuated Tube Collector (ETC) is presented for drying of cassava slices under the meteorological conditions of Thanjavur, Tamilnadu, India. Further the morphological, structural and physical properties of thin layer drying kinetics are studied and compared with natural sun drying. The designed dryer reduces the moisture content of cassava from 91.5% (wb) to 10.67% (wb) which is considered to be a safe level for storage in 8 h. There is a wide scope to save the conventional fuel by adopting the designed solar dryer as the air temperature inside the chamber rise is 30–40 °C than the ambient temperature. Non – linear regression analysis is performed to find out the drying kinetics of cassava using IBM SPSS 23 statistical package. Two - term model is proved to be the most suitable model for predicting thin-layer drying behaviour of cassava slices with R2 = 0.982, χ2 = 0.017553 for hybrid dryer and R2 = 0.998, χ2 = 0.001247 for open sun drying. XRD results exhibit ‘A’ type crystalline pattern that indicates semi–crystalline nature of cassava for both hybrid and sun dried cassava. Structural, morphological and proximate composition analysis reveals that the quality of hybrid dried cassava is better in terms of physical and chemical compositions than sun dried cassava. The proposed hybrid dryer is capable of producing high standard dried products for exporting and can make a good profit.

Cyclic drying has been reported as an innovative drying technique for the drying of food materials in terms of drying time, energy cost and product quality. In this study, drying characteristics and product quality of continuous and cyclic drying of Mytilus galloprovincialis in a convective solar dryer were investigated. A two-stage increasing–decreasing drying air temperature (sinusoidal pattern) of the solar dryer was used to obtain the desired cyclical variation of the drying temperature while keeping other drying air parameters constants. The advantages of employing cyclic heating on the drying kinetics, energy consumption are demonstrated. Analytical results illustrated an effective drying time of mussels by a reduction of 1.5% and optimum energy consumption does not exceed 23 kWh of drying process by applying cyclic drying technique compared to continuous drying of air temperature. Furthermore, According to the proximate composition of AOAC method and following Total viable count (TPC) of the dried mussels, it was observed that cyclic air temperature allows to yield higher retention of protein, glycogen, reduce significantly the effect of stresses compared to the constant conditions of drying, and it is possible the reduce the overall color change as well as an accepted texture. Several empirical and semi-empirical models were used to fitting drying curves of experimental data. It was found that the Page model seems to be most suitable to describe the drying curves of Mytilus galloprovincialis. The second law of Fick’s was used to determine the effective moisture diffusivity at different conditions of drying. As results, the values of effective diffusivity obtained by applying cyclic drying were in the margin with the drying at constant conditions that was reached 2.84 × 10−9 m2/s.

The storage of high moisture crop for longer duration is not possible because of its faster degradation due to the presence of excess moisture. The drying of crops makes them suitable for storage without getting spoiled. The hybrid active greenhouse dryers are suitable for drying such high moisture products. In this greenhouse dryer, the hot water from evacuated tube solar collector is supplied to the heat exchanger kept in the drying chamber which also acts as the drying bed for the products to be dried. In our experimentation, ginger has been dried from 92.8% (wb) to 10% (wb) moisture content in 21 h. The maximum air temperature inside the greenhouse is 55.33 °C. The economic and environmental feasibility of the dryer is tested in the paper. The dryer is capable of producing 232 kg of dried ginger annually with payback time of 1.15 years only. In its entire lifetime, the dryer will mitigate 16.41 tonnes of CO2 that prove it as a sustainable solution for drying purpose.

A combined conventional and microwave drying process for Ximeng lignite was investigated in this paper. Samples were firstly dehydrated by hot air to achieve a conversion moisture content, and then were managed to final moisture content by microwave drying. Results showed that the drying rate was significantly improved in the decreasing rate period by microwave drying, approximately 3–5 times faster than that of conventional drying. Finally, the orthogonal test was used to clarify the effects of each factor on the energy consumption, and the magnitude ranking order was conversion moisture content > microwave power > hot air temperature.

Drying is a very important stage in the treatment of spent coffee grounds destined to biofuels production. The mass transfer during the convective drying of spent coffee grounds generated in the soluble coffee industry is analyzed. An experimental design from sixteen isothermal drying experiments for different sample thicknesses (5 mm, 10 mm, 15 mm and 20 mm) and drying air temperatures (100 °C, 150 °C, 200 °C and 250 °C) using a drying air velocity of 1 m s−1 was proposed. Drying times, drying rates and effective diffusivity coefficients were obtained. Drying curves were fitted with the main mathematical model proposed in the literature, and the drying rates were studied from the moisture ratio and the drying air temperature. Constant and time-dependence effective diffusivity was evaluated using polynomial surface models. Drying times range between 18 min (test at 5 mm and 250 °C) and 3 h (test at 20 mm and 100 °C). Drying rate and effective diffusivity values were found between 0.0000226 and 0.001722 s−1 and 1.79 × 10−9 and 29.1 × 10−9 m2 s−1, respectively. The main differences between these experiments and those carried out by the same authors about the drying of spent coffee grounds obtained in the services sector were studied and analyzed.

The purpose of this study is to test and evaluate the effect of drying temperature on the behavior of moisture content and relative humidity of the drying air and drying time of orchid plants at four different levels of temperature. An experimental dryer was designed and installed with local components, which can control the temperature under study to the levels of (35, 40 , 45 and 50 oC) with a corresponding relative humidity of to the levels of (32.2, 28.3, 24.5 and21.2) respectively. The air speed was adjusted at (1.5 m / s) to achieve maximum utilization of energy used in drying. The average primary moisture content of the rosemary was 80% on a wet basis. There is an inverse relationship between the temperature and relative humidity of the air inside the dryer where the relative humidity of the air decreases from 32.2% to 21.2% when the temperature increased from 35 to 50 oC . There is an inverse relationship between temperature and final moisture content values ​​where the final moisture content is reduced from 80 to 32.65% on a dry basis with temperatures increasing from 35 to 50 ° C. There is a difference between the temperature in and out of the drying air and the difference is greater at the beginning of the drying process has decreased to reach the lowest value at the end of the drying process. The highest value of the relative humidity outside of the air was at the beginning of the drying process and it was reduced during the drying process until it reaches its lowest value at the end of the drying process. There is an inverse relation between temperature and drying time, the higher the temperature the lower the drying time.

Drying of black pepper has been investigated in a lab-scale conventional spouted bed dryer. Spouting behavior of black pepper was studied, and the minimum spouting velocity was determined. The effect of operational conditions; drying temperature, air velocity and stagnant bed height on drying kinetics was analysed. The higher values of drying rates were achieved when the dryer was operated with moderately high temperatures, high airflow rates and shallow beds. The results show an increase in effective moisture diffusivity with increasing drying temperature. The highest effective moisture diffusivity of 2.03 × 10-10 m2/s was obtained at a hot air temperature of 75 °C. Extraction and analysis of essential oil from dried black pepper showed that the variation of oil yield with drying temperature is significant for drying temperatures from 45 °C to 75 °C 65 °C was selected as the best drying temperature for black pepper drying in the conventional spouted bed dryer.

The increasing consumption of animal products will give rise to a huge demand of animal feed. Meeting this demand will be a challenge, given the scarcity of natural resources such as land and water. The major waste produced includes the organic waste such as peel, stem, core, seeds and pomace. In case of aonla pomace sample, drying time at 45, 55 and 65 °C was 210, 180 and 165 min respectively. Moisture loss was found to be temperature dependent and slow at lower temperature and took more time as compared to drying at higher temperatures. It can also be observed from these curves that the drying time decreased with increase in drying air temperature.

Drying is an important step in the preparation of white noodles popular as sohun. The process aims to remove moisture content.in wet sohun up to 14.5% referring to Industry National Standard of Indonesia. White noodles were commonly dried with direct sunlight in which was weather dependency both for process continuity and product quality. The paper discusses the effect of air dehumidification with several solid moisture adsorbents such as natural zeolite and synthetic zeolite on the thermal efficiency of sohun drying. At this point, the sohun was dried under air temperature 50 °C, 60 °C, and ambient temperature. The moisture content in sohun was observed every 15 minutes for operational drying time 150 minutes. As a comparison, the conventional drying without heating the air was also evaluated. Results showed that the higher air temperature resulted in faster drying time. With adsorbents, the performance of the dryer can be improved where the synthetic zeolite was the most superior compare to the others.

The aim of this paper is to present the influence of convective drying of organic pear pulp and adding ascorbic acid on changes in color, the difference in vitamin C content and also show the kinetics of convective drying. It was a two-factor experiment. The first factor was the air temperature needed for drying, between 45 °C and 65 °C, with a constant speed of drying air of 1.5 m/s; the second factor of the experiment was the adding of ascorbic acid to the pear pulp in the amount of 1 % and 2 % of the full mass of the prepared pulp. The lowest change in color was achieved by adding ascorbic acid in the amount of 2 % of the full mass of the pulp and drying air temperature of 45°C (ΔE= 23.981). The highest change was accomplished at the air temperature of 65 °C and by adding ascorbic acid in the amount of 1% (ΔE= 30.039). With samples where ascorbic acid was added reduction of vitamin C was over 99 % with all samples. By examining the kinetics of convective drying based on statistical indicators R, X2, RMSE, models Page and Logarithmic are the best in representing convective drying of pear pulp at air temperatures of od 65 °C and 45 °C respectively.

In order to avoid perishable characteristics and secure long shelf life of liquid milk, it is mostly converted into more stable derivatives such as butter, cheese, yogurt and milk powder. Amongst them, milk powder contains highest shelf life at ambient conditions and accounts for 76% of global annual trade of milk and milk derivatives. The milk powder production and its qualitative features are often characterized by huge amount of high- and low-grade energy requirements depending upon the number of stages employed for drying, e.g. single, two or three. In the present work, comparative thermodynamic analysis of two- and three-stage milk drying units has been executed. Both the units have been extensively explored on the grounds of parameters such as exergy efficiency (72.01%/43.67%), drying efficiency (67.50%/65.71%), drying chamber efficiency (57.77%/53.51%), exhaust air temperature (346.15 K/353.15 K), overall specific exergy destruction (3081.64 kJ/kg/5006.28 kJ/kg), overall specific exergy consumption (0.74 kWh/kg/1.34 kWh/kg) and sustainability indices (3.57/1.78) so as to establish the fact that the thermodynamic behaviour of two-stage spray dryer was far better than its three-stage counterpart, at the cost of slightly higher specific steam consumption (3.53 kg/kg/2.77 kg/kg).

Gasification is a potential technology to convert municipal solid waste into energy in the form of syngas. Addition of air to the pyrolysis zone and oxidation was carried out by modifying a single-stage downdraft gasifier into a multistage air inlet. The results showed an increase in the syngas heating value and decreased tar content. To determine the performance, the effects of equivalent ratio, preheated air temperature, and air ratio were studied. When the equivalent ratio is increased, the flammable gas and LHV decrease. The optimum conditions were obtained for the equivalent ratio (ER) of 0.4, where the percentage of CO and H₂ increased at an oxidation temperature of 902 °C. The variation of the air ratio has a stronger influence than the effect of the equivalent ratio because at the same equivalent ratio an increase in pyrolysis temperature of 674 °C is favorable to reforming tar from primary tar to secondary tar. The CO percentage increased significantly from 18.17% to 22.51%. Air preheating is useful to improve gasification performance, which was characterized by an increase in LHV from 5254 to 5976 kJ/kg. The optimum equivalent ratio and air ratio were 0.4 and 40:60, respectively, and effectively reduced the tar content from 50.02 to 27.82 mg/Nm³. The results of this study can be used to optimize multistage gasifier performance using air preheating and a multistage air inlet.

Among the various species of microalgae, Spirulina platensis has recently attracted attention from food and pharmaceutical industries due to its high contents of protein and bioactive compounds. Due to its high moisture content, a major challenge in the use of this microalga is its perishability. In this work, we investigated the use of a non-conventional rotary dryer (with an inert bed) for drying microalga Spirulina platensis. We quantified the effects of air temperature, feed rate, rotation speed, and filling degree of the inert particles on process performance. We then performed an optimization study using the Differential Evolution algorithm to identify the operating conditions that maximize process yield. We also performed a DEM simulation to gain a better understanding of the fluid dynamics. The results prove that this non-conventional system offers an interesting alternative for expanding use of this biomass, when performed under appropriate operating conditions.

Drying method that is applied in flour manufacturing industry, one of which is pneumatic drying. Variable types of both the properties of the dried material and the conditions of the drying process greatly affect the quality of the results of drying. Water content is an important variable in determining the quality of flour. The purpose of this study was to find the effect of drying air temperature on the moisture content of cassava flour under the conditions of the pneumatic drying process. Drying of cassava flour at desiccant air temperatures of 145oC and 160oC with 2 drying cycles produced a moisture content of 11.3 and 8.7% wb and had fulfilled SNI for flour water content, which was a maximum of 12% wb. The higher the temperature of the drying air, the lower the moisture content.

Transgenic ever-bearing strawberry (Fragaria×ananassa Duch. ‘HS 138’) was cultivated in a closed plant production system to produce functional proteins that can enhance human immune functions. We investigated the effects of air temperature before harvest on fruit growth and the concentration of human adiponectin (hAdi) at harvest in transgenic strawberry. During the different stages of maturity (mature white and immature green stages), hAdi-expressing plants were exposed to four air temperature treatments (15, 20, 25, and 30°C) under 24-h illumination provided by fluorescent lamps. Fruits were harvested at the mature red stage. The number of days to the mature red stage decreased with increasing air temperature, being the least at 30°C. Fruit total soluble protein (TSP) concentration increased with decreasing air temperature, particularly at 15°C, whereas fruit hAdi concentration tended to be higher under the 30°C treatment than under any other of the temperature treatments. There was no significant relationship between fruit fresh weight at harvest time and hAdi concentration within treatments, nor between the number of days to harvest and hAdi or TSP concentration. Although there were no significant differences in fruit hAdi content among treatments, hAdi production rate was the highest at 30°C because of the shortest duration to harvest. These results indicate that a higher air temperature promoted fruit maturation and accelerated the production of functional hAdi proteins in the fruit. For hAdi-expressing strawberry plants, exposure to 30°C may reduce energy consumption (lighting and air conditioning) for functional protein production under controlled environments.

The five most widely used mathematical models, which were additionally extended with a dimensionless coefficient (i.e. the drying air temperature), were examined for the best approximation of strawberry pulp convective drying in a thin stagnant layer. Furthermore, the effects of the drying air temperature and ascorbic acid on changes in the color of strawberry pulp during the drying process were examined. The statistical parameters of the mathematical models (namely R, X2 , RMSE) indicated that the Extended Modified Page model had the best fit for the convective drying of strawberry pulp. The changes in the color of the dried control sample, without the addition of ascorbic acid, were ΔE = 22.95 and ΔE = 25.71 at air temperatures of 45 °C and 65 °C, respectively. The greatest change in the sample color (ΔE = 14.66) was observed at an air temperature of 45 °C and an ascorbic acid additive value of 0.5 %. However, the smallest change in the sample color (ΔE = 12.57) was observed at an air temperature of 65 °C with the addition of 1 % ascorbic acid.

This study examined the performance of different combined infrared (IR) and hot-air drying (HAD) strategies for sweet potato. Experiments were conducted for simultaneous infrared and hot-air drying, two-stage sequential hot-air and infrared drying, two-stage sequential infrared and hot-air drying, and intermittent infrared and hot-air drying in a laboratory scale combined infrared and hot-air dryer. The drying air temperature varied between 50 and 70 °C, the infrared intensity was 1100 W/m2, the air-velocity was 1.5 m/s, and the pulse ratio (PR) ranged from 1 to 3. Results indicated that the drying rate, drying time, effective moisture diffusivity, shrinkage, specific energy consumption (SEC), colour attributes and phytochemical compounds of sweet potato were affected by the different drying combination strategies. The drying kinetics, product shrinkage, and sample temperature were also influenced by drying time and air temperature. The two-term exponential model adequately explained the drying behaviour of sweet potato for all the different combination strategies. The intermittent IR and HAD combination strategy proved to be the most suitable based on the combined effect of total drying time (113–120 min), SEC (27.67–41.44 kWh/kg), total colour change (17.15–26.48) and bioactive compounds.

In this research, the effects of intermittent drying variables on some quality properties of parboiled rice were investigated, then a mathematical model was applied to predict the value of quality features non-destructively using response surface methodology (RSM). The intermittent drying variables consisted of hot air temperature (40, 50 and 60?C), radiation intensity (0.21, 0.31 and 0.41 W/cm2) and microwave power (100, 200 and 300 W). The intermittent drying was performed at two stages with a tempering time between drying steps using a hybrid drying of hot air?infrared radiation and microwave drying at the first stage and second stage, respectively. According to RSM results, the effect of drying variables on the quality properties of parboiled rice were significant (p < 0.01). Also, the best mathematical model for prediction of quality properties of samples was the quadratic equation (R2 = 0.96-0.98). The HRY (61.8-73.2%), hardness (118.63-215.27 N) and color value (17.28-19.22) increased, while the lightness (64.17-59.51) decreased during drying. RSM can be able to predict the optimization parameters for the best quality properties (i.e., HRY = 72.42%, lightness = 59.47, color value = 19.25 and hardness = 213.91 N) based on temperature of 60?C, radiation of 0.41 W/cm2 and power of 300 W.

The present investigation was carried with the objective of developing kiwi fruit leather using different hydrocolloids. Hydrocolloids like xanthan gum (XG), guar gum (GG), and pectin (P) in three different concentrations, that is, 0.2%, 0.5%, and 1% were blended with kiwi pulp and were dried at 60°C for around 7 hr. The developed kiwi fruit leathers were analyzed for physicochemical, color, textural and organoleptic properties. The leather samples prepared with 0.5% XG, 0.5% GG, and 0.5% P showed the highest sensory score and desirable physicochemical properties. The effects of air temperature (50, 60, 70°C) and hydrocolloids (0.5% of XG, GG, and P) on the drying kinetics of kiwi fruit leather were investigated. The mathematical modeling was performed by seven thin layer drying models. The Midilli‐Kucuk model was found to satisfactorily describe the thin layer drying kinetics of kiwi fruit leather. PRACTICAL APPLICATIONS: Kiwifruit is a rich source of vitamins, minerals, antioxidants, phytochemicals, and fiber content. It offers specific health benefits and has great potential for industrial exploitation. However, this fruit and its products are not reachable to all consumers. Fruit leathers are an economical and convenient substitute for natural fruits with high nutritional values. But leather making from kiwifruit and leather drying is a challenging task. Hence, it was hypothesized that xanthan gum, guar gum, and pectin could be effective for providing desirable textural, and organoleptic properties. Thus, the objectives of this study were to evaluate the effects of xanthan gum, guar gum, and pectin and their concentrations on the characteristics of kiwi fruit leather and to investigate the effect of drying air temperature on the drying kinetics of kiwi fruit leather. This study will provide an opportunity to food industries for the effective utilization of kiwifruit.

Fluidized bed drying of rough rice in the U.S. has not been utilized to its full potential due to the lack of research to address quality reduction and higher energy consumption. Not much research was done to analyze the energy and exergy of the rough rice's fluidized bed drying. Drying air temperature (40°C, 45°C, 50°C), drying bed condition (fluidized and fixed), drying duration (30 min, 45 min, 60 min), and ambient air dehumidification (yes, no) were the factors of this study. Lab-scale dryer units designed by Sadaka et al. (2018) were used. Three replicates were performed to eradicate any bias or human errors. All factors did significantly affect the energy and exergy of the drying except dehumidification and replication. The minimum and maximum EU values were 0.01 kJ/s and 0.55 kJ/s for drying at fixed bed drying at 40°C for 30 min with dehumidification and at 50°C for 60 min under fluidized bed condition without dehumidification, respectively. Minimum and maximum exergy efficiency values were 13.46% and 49.14%, achieved at 45°C air temperature for fixed bed with dehumidification for 45 min duration, and fluidized bed drying using 40°C air temperature for 60 min with dehumidification, respectively. At the drying process's primary stages, fluidized bed drying had higher exergy efficiency, energy utilization, and energy utilization ratio than the fixed bed drying method. 40°C air temperature using fluidized bed drying with or without ambient air dehumidification worked best as per the energy and exergy utilization in the drying system.

Tea has become an important crop in a many regions of the world. India is one of the best quality tea producers in the world. Despite of being an important cash crop, much research has not been made on tea, due to which modern drying technologies have not been employed in this regard. This work reflects the drying characteristics for tea in a bubbling conical bed dryer. Fresh Assam tea leaves have been processed into crush, tear, and curl (CTC) tea initially, followed by fermentation and drying in a conical bubbling fluidized bed dryer. The effect of various parameters, such as drying air temperature, superficial air velocity, inventory, and cone angle, on moisture removal rate from CTC tea in the conical bed dryer has been experimentally investigated and analyzed in this present work. Drying temperature and superficial air velocity are found to be the major parameter that affects the moisture removal rate from tea. The moisture removal rate from tea varies proportionally with the increase in drying temperature, but the quality deteriorates after a certain limit of temperature. Different cone angles of 0°, 5°, and 10° for the conical bubbling fluidized bed dryer are also inquired into for a static inventory bed height of 15 cm. It is found that moisture removal rate is highest for the case 10° cone angle of the dryer.

Crude oil entering the sea will be caused change in tension, viscosity, volume and etc. This process is called emulsification of crude oil. This paper found that the density of crude oil with asphalt content 7% increase with the increase of emulsification and decreases gradually with temperature increment during emulsification through experiments in laboratory. Tension and viscosity of crude oil increase with emulsification, but it decrease with temperature rise. The study found that the wind speed > 3.5 m/s is conducive to crude oil volatilization, and also found that the continuous volatilization of thick oil film is greater than that of thin oil film under the same wind speed in laboratory. Under natural conditions, it was found that when the wind speeds was less than 2 m/s, the temperature had greater effect on evaporation (air temperature >32 °C ) and the volatilization increased with the increase of air temperature for crude oil. Emulsification and weathering characteristics of crude oil with different content of asphalt content are studied; it is helpful to monitor offshore oil leakage by remote sensing.

Pomegranate juice processing produces a large amount of peel as a by-product or waste which is a potential source of raw material for food and other bioprocessing industries, such as(fights acne, pimples and rashes, helps in detoxification of body, cures sore throats and coughs, arrests hair loss and prevents dandruff, improves dental hygiene). Drying the peel offers opportunities for value addition into novel products, thus reducing amount of produced waste from the fruit processing operations. The dry parameter was drying air temperature (65, 75 and 85°C) and drying air velocity (1, 2 and 3 m/s) at layer thickness of 7mm. The results indicated that the initial moisture content of 244% (d.b) decreased to a range between 6 and 4% (d.b) at the end of drying process depending on the drying conditions. The results obtained show that moisture content of the by-product decreases with time and temperature. Two thin-layer drying models were selected to describe experimental drying kinetics data. The models were compared based on their coefficients of determination (R2), reduced chi square (χ2) and root mean square error (RMSE) between Observed and predicted moisture ratios. On the other hands, the calculated operation cost of the dryer approaches about 5.5 E/kg, while the price of 1 kg of dried pomegranate peel is 35 LE in the market.

PT Petrokimia Gresik is the Complete Fertilizer Manufacturer in Indonesia which produces various kinds of fertilizers and chemicals for agro-industrial solutions. Ammonia (NH3) is one of the results of chemical production at PT Petrokimia Gresik which poses a risk to the health of ammonia factory workers at PT Petrokimia Gresik. The purpose of this study is to analyze the risk of exposure to ammonia (NH 3 ) gas in ammonia I factory workers of PT Petrokimia Gresik. This study is a descriptive survey using Environmental Health Risk Analysis approach. The data analysis method used was risk analysis to determine the risk characterization of PT Petrokimia Gresik ammonia (NH 3 ) I workers. The level of risk is said to be safe if RQ ≤ 1, and the level of risk is said to be unsafe if RQ> 1. The results showed that the average concentration of ammonia (NH 3 ) gas was 6.6 mg / m 3 , the highest concentration was 9.2 mg / m 3 , the lowest concentration was 4.3 mg / m 3 . The physical air environment obtained at an average air temperature of 36 o C, the average air humidity was 43%, the average wind speed was 0.85 m / s and the wind direction when the measurements blew from the West and East. Agents at risk of causing health problems to workers at ammonia I factory of PT Petrokimia Gresik were ammonia (NH 3 ) gas in the work environment air sourced from the ammonia (NH 3 ) gas production process, and 57% of the ammonia I factory workers of PT Petrokimia Gresik had a history of respiratory disorder. The response dose of ammonia (NH 3 ) gas was 5x10-1 mg / m 3 . All ammonia I factory workers at PT Petrokimia Gresik obtained a minimum concentration, average concentration and maximum concentration of RQ

Rice is one of the important food crops in Indonesia. It is known as a staple food of Indonesian society. The consumption patterns of rice are slowly but surely increase with increasing income, education and access to information. Increasing demand for rice in the country reaches 1.6% per year. One of the problems that arise in the process of rice production is the drying process. Generally, the unhulled rice drying process in Indonesia is carried out directly in the sun. This method has many limitations. In this study, the drying method used is a fluidized bed. The purpose of this study is to determine the effect of the intake air temperature and unhulled rice mass on drying time. The intake air temperatures used were 40, 45, 50 °C. The results show that the fastest drying process to obtain the final moisture content of 13.1% from the initial moisture content of about 22% is achieved using the intake air temperature of 50 °C. The drying process takes about 40 min; however, the increased drying process speed is not linearly with the increase in the intake air temperature.

An integrated solar system was examined and worked for drying chamomile during the summer season 2013 in Germany. The system consisted of collector, heat exchanger, reflector, main drying chamber below collector, additional drying chamber and supplementary electric heaters immersed in water tank. It could also storage of solar energy into water during the time of sun-shine and reuse this energy at cloudy weather or off sunshine time to raise the temperature of drying air inside the system. The capacity of main drying chamber ranged 32–35 kg of fresh chamomile and 10–12 kg for the other separate drying chamber. Air temperature inside the dryer could be maintained as desired range for drying chamomile using a temperature controller. The integrated dryer was operated about 30–33 h to reduce the moisture contents of chamomile from 72-75%–6% (wb) compared to 60 h to reduce it to 9–10% (wb) using open sun drying method. Nine mathematical models for drying kinetics of chamomile were tested to determine the parameters of the best suitable models for those plants. It is found Midili model was the best model to define drying kinetics of chamomile for the main and additional drying chambers in solar system.

Sugarcane juice (JCP) and whey protein concentrate (WPC) are products of great interest due to their contributions of carbohydrates and proteins, respectively, and they have the ability to be transformed into powdered products. In this work, the influence of spray drying conditions on the processing performance and physicochemical properties of the JCP and WPC combined system were evaluated through applying a response surface methodology by central composite design. The independent variables were as follows: inlet air temperature (130–180 °C), outlet air temperature (75–90 °C), atomizer disk speed (21,000–26,000 rpm) and WPC contribution in the feed (40–90% d.b.). The results indicated that the drying process conditions had a significant statistical effect (p

Water removal is one of the main objectives of sewage sludge composting to reduce the volume and mass of sewage sludge. In this study, the effect of aeration strategy and ambient temperature (summer and winter) on composting pile temperature, moisture content, and volatile solid (VS) change were studied during sewage sludge composting processes in a well-operated sludge composting plant. The results showed that the temperatures of the composting pile could remain above 55°C for more than 3 days under all conditions, which was sufficient to meet the requirement of harmless treatment. Moisture content of composting material decreased from 65%–69% to 39.2%–52.6% within 20 days, and VS decreased to about 77%. In the end of the composting process, cumulative water removal was 0.45–0.47 kg/kg in summer, which was significantly higher than that in winter (0.35–0.36 kg/kg). When the average aeration rate was fixed, aeration strategy with a smaller aeration rate and higher on/off time ratio showed more wat...

Sliced fruits (apple and kiwi) were dried under atmospheric freeze-drying (AFD) and/or low-temperature drying (LTD) conditions, and the drying kinetics, resultant degree of shrinkage, and vitamin C retention were evaluated. The air temperature programs were set in the range of −20 to 10 °C, and the impact of the sub-zero temperature setting was investigated. As expected, shortening the sub-zero temperature time and increasing the air temperature led to a shorter total drying time. Notably, the application of freezing had an effect to reduce the drying time. The application of the LTD condition without freezing significantly increased the total drying time compared with that of the drying condition with freezing. When the temperature was increased stepwise from −20 to 10 °C, the total drying time was effectively reduced when the sub-zero temperature was maintained for a relatively long time. This was the most practical drying program for maintaining product quality. It was found that drying at sub-zero temperatures has advantages in reducing product shrinkage; however, the impact was not remarkable. The application of sub-zero temperature conditions was advantageous for vitamin C retention for both apple and kiwi drying. However, if the negative effect of freezing on quality is significant, simple LTD conditions may be a good compromise for balancing total drying time and product quality.

Heat pump drying is an energy-saving method for drying sludge. However, the existing research on sludge drying characteristics is not consistent with the operating temperature of a heat pump. In particular, the effect of relative humidity is often neglected. To comprehensively investigate the effects of air parameters, sludge drying characteristics were investigated under the conditions of air temperature 40–70 °C, air velocity 1.0–2.0 m/s and relative humidity 20–40%. The results showed that the effect of relative humidity on the sludge drying characteristics cannot be neglected under low-temperature conditions. Specifically, the drying time was extended by 10–60 min for every 10% increase in relative humidity. Moreover, the sensitivity indicators of temperature, air velocity, and relative humidity on the drying time were 0.470, 0.232 and 0.025, respectively. Furthermore, the relative humidity was introduced into the drying model coefficients to improve prediction ability. Under the verification conditions, the prediction deviation of the drying time of the multiple linear regression was 14.1%, while the least square support vector machine reduced the deviation to 5.5%.

In the present study, we applied and improved a model to describe the behavior of a spouted bed dryer with intermittent feeding for suspension drying, considering suspension accumulation inside the device. This model is important in macroscopic heat and mass balances, represented by a system of ordinary differential balances, implemented and resolved numerically using Fortran routines, in which the influence of process variables on drying dynamics were assessed. The results obtained in modeling and mathematical simulations were compared with experimental data, indicating that the model fits the process well, based on outlet air temperature and moisture.

This paper presents experimental performance of the greenhouse solar dryer for drying of cassumunar ginger (Plai). The dryer consists of a parabolic roof structure covered with polycarbonate plates on a concrete floor. The base of the dryer is a concrete floor with an area of 9 × 12.4 m2. Nine DC fans powered by three 50-W PV module were used to ventilate the dryer. The dryer was installed at Sa Kaeo province (13.49°N, 102.21°E), east of Thailand. To investigate the experimental performances, 300 kg of cassumunar ginger was dried in the solar greenhouse dryer. The drying air temperature varied from 30 °C to 55 °C during drying. The drying time in the solar greenhouse dryer was 1 day to dry cassumunar ginger from an initial moisture content of 90% (wb) to a final moisture content of 10% (wb), whereas it required 1 day of natural sun drying under similar conditions to reach a moisture content of 40% (wb). A system of partial differential equations describing heat and moisture transfer during drying of cassumunar ginger in the solar greenhouse dryer was developed and solved numerically using the finite difference method. Good agreement was found between experimental and simulated moisture contents.

A double-sided solar collector dryer was designed to be installed on both sides of a drying chamber. The solar collector was tilted at an angle of 15° to the ground and had a total receiving area of 7 m2. After drying banana from an initial moisture content of 68.5% (w.b.) for 5 days, the banana final moisture contents in the dryer and from open sun drying were 17.4% (w.b.) and 27.3% (w.b.) respectively. The highest air temperature in the drying chamber was 62.7 °C and the average temperature was 54.1 °C, which was 13.6 °C higher than from natural sun drying. The high drying rate of the solar collector dryer reduced the banana moisture content 1.3–1.5 times faster than by sun drying. The average thermal efficiency for the dryer and solar collector were 13% and 21.9%, respectively.

The main phenomena involved in the food refrigeration process are heat and mass transfer. In this context, the aim of this study was to evaluate the influence of refrigeration system parameters on food quality during postharvest storage. Experiments were conducted where the mean air temperature, air temperature fluctuation, air velocity, thermal oscillation period and humidity ratio were controlled, to quantify the food mass transfer, cooling rates and sensorial acceptance. The food sample under evaluation was lettuce packed in perforated polyethylene bags. A standardized test (IEC 63169:2020) was performed under the same experimental conditions for comparison. Food cooling rate was influenced by air velocity and a gradual increase (0.1–1.1 °C) in food temperature was observed during storage. A temperature increase from 3.0 to 7.0 °C, raised the mass loss of the food by 8.8%, which was directly influenced by the driving force provided by the humidity. Higher temperature fluctuations led to negative results in the sensorial analysis, with less freshness and higher consumption rejection.

This research work aimed to obtain blackberry pulp powder by spray drying and, by an experimental design, evaluated the effect of inlet air temperature (100-150 °C) and blackberry pulp solids:arrowroot starch/gum arabic solids ratio of 1:0.5-1:2 on the physicochemical properties of the powders. Arrowroot starch and gum arabic present glass transition temperature (Tg) values above 100 °C; hence it was possible to employ them as carriers in blackberry pulp spray drying in order to increase Tg of the system. Powder yield and solubility increased with increasing blackberry pulp solids:arrowroot starch/gum arabic solids ratio of 1:0.5-1:2, whereas hygroscopicity decreased. Yield, solubility and hygroscopicity of the powders increased and water activity decreased, with increasing inlet air temperature. The powders presented low moisture content and water activity. Temperature of 143 °C and blackberry pulp solids:arrowroot starch/gum arabic solids ratio of 1:1.78 were the optimal conditions to obtain high yield and blackberry powders that are soluble in water and less hygroscopic.

In the present paper, the performances of a solar desiccant air conditioning system coupled with the condenser for distillate water production are numerically investigated. The aim of the present study condensed the water vapor from the regeneration air out from a solar desiccant air conditioning by feeding it to the condenser to production the distillate water. Production the distillate water, air conditioning, and energy saving represent the objective of this study. The results show that (i) as process air discharge increases from 150–450 m3/h, supply air temperature increases from 18.5–21.6 °C, distillate production decreases from 1.635–0.105 l/h, cooling COP increases from 0.406–0.724, and overall COP decreases from 0.918–0.873 (ii) as the regeneration air discharge increases from 75–225 m3/h, supply air temperature decreases from 21.8–18.4 °C, distillate production increases from 0.009–3.024 l/h, cooling COP decreases from 0.714–0.431, and overall COP increases from 0.718–1.029 (iii) as the regeneration temperature increases from 75–100 °C, supply air temperature decreases from 21.2–18.9 °C, distillate production increases from 0.285–1.41 l/h, cooling COP decreases from 0.704–0.555, and overall COP increases from 0.815–0.926.

Drying harvested microalgae from an average moisture content of 80% wet basis to a safe moisture content of 10% is challenging. Removing this high amount of water from microalgal biomass is time-co...