Studying the Sublimation of Carbon Dioxide

Abstract

Background: The utilization of dry ice in cooling and storage units requires adjusting the intensity of sublimation due to the requirements of prudently using CO2 to maintain preset thermal conditions. Aim: When designing a carbon dioxide cycle, it is essential to consider the influence of thermal gradients on the adsorption and desorption of carbon dioxide. Methods: tests were conducted to study the production and sublimation of carbon dioxide. The testes were aimed to define the temperature relation of the dry ice sublimation period, the density of pressed СО2, and the humidity of the environment and concentration. Results and Discussion: According to the obtained test data, there was a linear relationship between the sublimation intensity and the ambient air temperature in the specified conditions. The effect of moisture condensation on the sublimation rate appeared weaker than expected, for the amount of moisture on the surface of the specimens was insignificant. The heat exchange was intensified by the fall of hoarfrost and the related surface expansion. However, much moisture froze out without reaching the dry ice surface, and the formed layer of ice formed a heat insulation surface, and the sublimation under that layer was less intensive. The direct influence of sublimation came from the pressure at which a specific specimen was formed; however, 75 kN pressure was optimal. Conclusion: Despite higher weight losses during the storage, the difference in spent energy is more critical than 90 kN. The factor no less important was the carbon dioxide storage temperature. The maximal sublimation time of a 55 g cylinder formed at 75 kN and stored at – 80°С was 135 hours, much higher than at similar parameters but at -60°С. That said, the amount of energy spent on operating a low-temperature chamber was almost identical.

Study of Rabbit Carcasses Cooling With Carbon Dioxide During Transportation

“…Также существенное влияние оказывает попадание сублимированных паров диоксида углерода в мясо в процессе диффузии, которая приводит к перераспределению и охлаждению жидкости в мясе. опыт (в упаковке) Исходное сырье 0,79×10 3 0,79×10 3 0,79×10 3 0,31×10 1 0,31×10 1 0,31×10 1 1 0,61×10 4 0,69×10 3 0,64×10 3 0,18×10 2 0,14×10 1 0,10×10 1 2 0,182×10 4 0,78×10 3 0,73×10 3 0,59×10 4 0,44×10 2 0,36×10 2 3 0,49×10 6 0,89×10 3 0,82×10 3 0,50×10 7 0,29×10 4 0,24×10 4 5 -0,324×10 4 0,219×10 4 -0,85×10 4 0,78×10 4 6 -0,58×10 5 0,401×10 4 -0,27×10 5 0,16×10 5 7 -0,91×10 6 0,82×10 6 -0,51×10 5 0,31×10 5 8 --0,147×10 6 --0,43×10 5 При дальнейшем хранении мяса наблюдается увеличение кислотности у всех образцов независимо от способа их охлаждения из-за развития окоченения, но больше всего это происходит у опытного образца, охлажденного диоксидом углерода. Как и в случае с другими аналогичными мясными продуктами, хранящимися охлажденными в воздушной среде, рН крольчатины увеличивается по мере хранения.…”

“…В качестве источника холода в последние годы используется диоксид углерода. Его применение обусловлено тем, что на данном этапе в мире остро стоит вопрос о защите окружающей среды от вредного воздействия различных веществ, фторсодержащих хладагентов и токсичных газов [5].…”

Effect of Low Temperatures on the Brittle Fracture of Hazelnut Shell

“…Most industrial nut crackers crush nuts between two rotating rollers, or between a roller and an unmoving surface. However, their efficiency remains below 1-1.5% [25,26].…”