Using of exhaust gas heat from a condenser to increase the vacuum freeze-drying rate

Ansar, Ansar; Sukmawaty,; Murad,; Ulfa, Maria; Azis, Atri Dewi

doi:10.1016/j.rineng.2021.100317

Cited by 9 publications

(5 citation statements)

References 29 publications

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“…The spray drying method is generally carried out by spraying the material in the form of fine droplets into a stream of hot air [ 25 , 26 ]. The drying process occurs very quickly, so this method is very suitable for heat-resistant materials at high temperatures [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

A new innovative breakthrough in the production of salt from bittern using a spray dryer

Ansar

Yahaya²,

Kamil³

et al. 2022

Heliyon

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Section: Introductionmentioning

confidence: 99%

A new innovative breakthrough in the production of salt from bittern using a spray dryer

Ansar

Yahaya²,

Kamil³

et al. 2022

Heliyon

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“…Optimization of the VFD to be more efficient is necessary to support sustainable energy use. Various efforts have been made to reduce the energy consumption of VFD such as utilizing the residual heat of the condenser exhaust [4,5], pre-treatment material before drying [6,7], combining VFD with other drying methods [1,8]. Design single or cascade VFD cooling systems can also affect its energy consumption.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Simulation of Cascade Cooling System for Vacuum Freeze Drying

Buana,

Kosasih

2024

J. Phys.: Conf. Ser.

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Vacuum freeze drying (VFD) is a drying method carried out at pressures and temperatures below the triple point of water. Drying occurs by sublimation. The results of the VFD method are able to maintain the quality of dry ingredients (taste, colour, nutrient, etc.). To achieve a condition below the triple point of water, it is conditioned so that the pressure is under a partial pressure of 6.11657 mbar at a temperature of 0.01°C. The refrigeration system is simulated using refrigerants R-134a and R-22. The purpose of the simulation is to obtain the optimum system conditions. The variables varied were the saturated temperature of the LTC (Low-Temperature Circuit) evaporator, the saturation temperature of the HTC (High-Temperature Circuit) evaporator, the difference in the temperature of the pinch point between the LTC condenser and the HTC evaporator and the temperature of the HTC condenser. The simulation results are the saturated temperature of the LTC evaporator -30°C, the saturation temperature of the HTC evaporator -15°C, the difference in the temperature of the pinch point between the LTC condenser and the HTC evaporator 10°C and the temperature of the HTC condenser 40°C. The highest Coefficient of Performance (COP) of the cascade cooling system with these parameters is 2.55 using a combination refrigerant R22 in HTC and R134a in LTC.

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“…Apart from that, the heating method in the drying chamber also affects the evaporation rate. Heating materials using infrared rays, microwaves, utilizing condenser waste heat and a combination of heating methods has an effect on the evaporation rate and energy consumption [9][10][11][12]. For example, Jia et al, [13] which compared the evaporation rate using the hot air heating method, hot air-microwave combination and vacuum freezing for drying persimmons including analysis of the physical-chemical properties of the dried product.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Effect of Air Humidity Ratio in the Drying Room on the Rate of Material Evaporation in Vacuum Freeze Drying

Indra Buana,

Engkos Achmad Kosasih

2024

ARFMTS

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In the drying process there are several parameters that influence the evaporation rate. Apart from pressure and temperature, air humidity in the drying room has been shown to influence the evaporation rate. To find out how much influence air humidity has on the evaporation rate in a Vacuum Freeze Dryer (VFD) system, calculations and simulations need to be carried out. Evaporation in a VFD occurs by sublimation at evaporation conditions below the triple point of water. Ice weighing 2x10-2 kg was used as dry material to characterize the VFD process at a temperature of -10oC. The ice temperature and operating pressure are selected at conditions below the triple point so that sublimation evaporation occurs. The temperature of the drying room for heating was varied, namely (20, 25, 30)(oC) and pressure (0.5, 0.4, 0.3)(kPa). Air humidity ratio, varies at (300, 200, 100, 10, 1, 0.1, 0.01, 0.001) (kg H2O/kg dry air). The simulation is carried out in a drying room, the ice receives heat due to the temperature difference with room temperature, heat transfer occurs by radiation and diffusion. Heat is used to evaporate the ice through sublimation. The temperature of the ice upon sublimation is close to the wet bulb temperature and remains constant until the ice has completely evaporated. From the simulation it is known that changing the air humidity ratio in the drying room from 300 (kg H2O/kg dry air) to 0.001 (kg H2O/kg dry air) will increase the evaporation rate between 6.2% - 9.5%. The evaporation rate increased by 6.2% was obtained at P∞=0.3kPa, T∞=30oC. This increase in evaporation rate shortened the drying time by 0.42 hours. The evaporation rate increased by 9.5% at a pressure of P∞=0.5kPA, T∞=20oC thereby shortening the drying time by 1.03 hours. Simulations show that increasing the evaporation rate and shortening the drying time has the potential to increase the energy efficiency of the VFD. The increase in evaporation rate is influenced by operating temperature and pressure. Simulations confirmed that the evaporation rate increased when the drying chamber temperature was increased and the air pressure was decreased.

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Using of exhaust gas heat from a condenser to increase the vacuum freeze-drying rate

Cited by 9 publications

References 29 publications

A new innovative breakthrough in the production of salt from bittern using a spray dryer

A new innovative breakthrough in the production of salt from bittern using a spray dryer

Thermodynamic Simulation of Cascade Cooling System for Vacuum Freeze Drying

Simulation of the Effect of Air Humidity Ratio in the Drying Room on the Rate of Material Evaporation in Vacuum Freeze Drying

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