Effect of Temperature and Pressureo on Moisture Diffusion Characteristics of Paddy (Cv. MTU 1075)
Uticaj temperature i pritiska na difuziju vlage u pirinču (Cv. MTU 1075)
Pregled/ Otvaranje
Autor
Bakhara, Chinmaya
Dash, Sanjaya
Pattnaik, Aditya
Panda, Manoj
Ključne reči
parboilinghydrostatic soaking
steaming
diffusion coefficient
predkuvanje
hidrostatičko natapanje
parenje
koeficient difuzije
Metadata
Prikaz svih podataka o dokumentuApstrakt
Parboiling is an important and energy intensive unit operation in rice
processing. Proper management of parboiling can reduce the energy requirement during
parboiling and the associated cost. Soaking and steaming are the two major steps in
parboiling. Soaking of paddy is usually carried out under atmospheric pressure, which
takes more time. The temperature of soak water affects the rate of moisture adsorption
and diffusion. The pressure during soaking and steaming also affects the process and
consequently, affects the overall economics of parboiling. The hydration characteristic of
paddy (Cv. MTU 1075) was studied at different conditions with the basic objective to
standardize parameters for these unit operations. Soaking was carried out at four levels
of soaking temperature under atmospheric pressure. Similarly hydrostatic soaking at
pressure levels of 2.0, 4.0 and 6.0 kg·cm-2 was studied at a constant soak water
temperature of 70°C. Steaming was carried out at 0.5, 1.0, 1.5, 2.0 and 2.5 kg·cm-2
pressure levels. The initial moisture content of paddy was varied at three levels. It was
observed that the soaking temperature and pressure and steaming pressure affected the
rate of moisture absorption by the grain and thus the time requirement. The diffusion
coefficient was independent of initial moisture content and showed Arrhenius type
relationship with temperature of soaking and steaming. The diffusion coefficient of
paddy ranged between 8.939 x 10-5 to 2.678 x 10-4 cm²·min-1 for steaming under
pressure, 7.01 x 10-6 to 1.399 x 10-5 cm²·min-1 for hydrostatic pressure soaking at 70°C
and 1.898 x 10-6 to 1.11 x 10-5 cm²·min-1 for soaking under atmospheric pressure at
different temperature. The diffusion constant was calculated as 0.01345 m²·min-1 and
activation energy for moisture diffusion was 35.19 kJ·g-mol-1. Predkuvanje je važan i energetski intenzivan postupak u preradi pirinča.
Pravilan postupak može da smanji potrošnju energije i prateće troškove. Natapanje i
parenje su dva glavna koraka u ovom postupku. Natapanje pirinča se obično izvodi pod
atmosverskim pritiskom, što traži više vremena. Temperatura vode utiče na adsorpciju i
difuziju vlage. Pritisak pri natapanju i parenju takođe utiče na process, a time i na
ukupne ekonomske efekte. Karakteristike hidriranja pirinča (Cv. MTU 1075) su
ispitivane pod različitim uslovima sa osnovnim ciljem da se standardizuju parametri za
ove operacije. Natapanje ke izvođeno pri četiri temperature pod atmosverskim pritiskom.
Hidrostatičko natapanje je izvođeno pri pritiscima od 2.0, 4.0 i 6.0 kg∙cm-2 na
konstantnoj temperature od 70°C. Natapanje je izvođeno pod pritiscima od 0.5, 1.0, 1.5,
2.0 i 2.5 kg∙cm-2. Inicijalni sadržaj vlage pirinča varirao je na tri nivoa. Uočeno je da
temperatura i pritisak natapanja i pritisak parenja utiču na adsorpciju vlage u zrno, a time
i na vreme trajanja postupka. Koeficijent difuzije je bio nezavistan od inicijalne vlažnosti
i pokazao je Arrhenius odnos sa temperaturom natapanja i parenja. Koeficijent difuzije
pirinča varirao je u interval 8.939 x 10-5 do 2.678 x 10-4 cm²∙min-1 za parenje pod
pritiskom, 7.01 x 10-6 do 1.399 x 10-5 cm²∙min-1 za hidrostatičko natapanje na 70°C i
1.898 x 10-6 do 1.11 x 10-5 cm²∙min-1 za natapanje pod atmosverskim pritiskom pri
različitoj temperature. Izračunata vrednost difuzione konstante je bila 0.01345 m²∙min-1,
a aktivaciona energija za difuziju vlage 35.19 kJ∙g-mol-1.