Study on drying characteristics of chemical treated slit green chillies under hot air oven

Chilli (Capsicum annuum L.) is one of the important commercial crops of India. It is a crop of tropical and subtropical regions and requires a warm humid climate. Chilli is a highly perishable vegetable with a short shelf-life and commonly encounter postharvest problems; to deal such problems, drying was done using hot air oven. Three different temperatures (50, 60 and 70 °C) use in hot air oven. Before drying chillis were slitted and treated with Butylated Hydroxy Anisole and Potassium Carbonate solution. Overall drying rate increased with temperature in hot air oven. Drying of dipsol green chilli took place in falling rate period. Initial moisture content of the green chilli was an average of 84.20±1 % w. b.

Kajian ulang transfer massa disertai reaksi kimia pada absorpsi reaktif gas CO2 pada packed column

This article reviewed researches have been carried out concerning simulation of enhancement factor for absorption accompanied by second order chemical reaction under non-isothermal condition and modeling of packed column for CO2 absorption in K2CO3 solution. The value of enhancement factor was predicted using eddy diffusivity model (King model) for describing interface mass transfer phenomena. System of differential equations developed in this modeling was solved with Orthogonal Collocation method. The value of E predicted from this research agrees very well with that predicted using Penetration model (Higbie model) by Vas Bhat (1997). The researches concerning packed column modeling was carried out experimentally and theoretically. Experimental works were carried out to validate theoretical prediction. Material studied in this research was CO2 –air mixture and potassium carbonate solution. Potassium carbonate solution was fed into top of the column and the solution was contacted counter currently with rising CO2-air mixture stream. The liquid leaving the column was analyzed by titration. Theoretical studies were carried out by developing microscopic mass and energy balance model on the packed column. The resulted system of first order differential equations were solved using Forth order Runge Kutta method. The solution of this model requires information concerning rate of gas-liquid interface mass transfer where King model was used in this study. Mass transfer, CO2, solubility, kinetics, and reaction equilibrium data required in this theoretical study were obtained from literatures (Danckwertz, 1970; Kohl and Riesenfeld,1985; and Treyball, 1981). In this research, the effect of absorbent flow rate and the concentration of K2CO3 in the inlet absorbent on percent recovery of CO2 gas was studied.Deviation between simulation prediction results and experimental data was below 10% for absorbent flow rate of 3 to 5 liter/menit and for absorbent flow rate of 5 to 7 liter/ menit the deviation was between 10 and 30%. Key words: mass transfer, eddy diffusivity, absorption, non-isotermal, packed column AbstrakArtikel ini mengkaji ulang penelitian-penelitian yang telah dilakukan mengenai simulasi enhancement factor absorpsi disertai reaksi reversible order dua kondisi non-isotermal dan pemodelan packed column untuk absorpsi gas CO2 kedalam larutan K2CO3 pada packed column. Harga enhancement factor diprediksi dengan menggunakan model eddy diffusivity (model King untuk perpindahan massa antar fasanya). Sistim persamaan diferensial yang dibentuk dari pemodelan ini diselesaikan dengan metoda Kolokasdi Ortogonal. Hasil prediksi harga E dari penelitian ini sangat mendekati hasil prediksi menggunakan model Penetrasi oleh Vas Bhat (1997). Penelitian pemodelan packed column dilaksanakan secara eksperimen dan simulasi. Penelitian secara eksperimen dilaksanakan untuk validasi hasil simulasi. Bahan yang digunakan adalah campuran CO2 dan udara serta larutan potasium karbonat. Larutan potasium karbonat dialirkan kedalam packed column dari atas dan dikontakkan secara berlawanan arah dengan aliran campuran CO2-udara dari bawah. Cairan keluar kolom dianalisa dengan titrasi. Sedangkan percobaan simulasi dilaksanakan dengan mengembangkan model neraca massa dan energy mikroskopik pada kolom. Sistim persamaan diferensial order satu yang dihasilkan diselesaikan dengan metoda Rung Kutta order empat. Solusi model ini memerlukan informasi mengenai laju transfer massa antar fasa gas-liquid yang dalam hal ini menggunakan model King. Data kelarutan CO2, data perpindahan massa, data kinetika dan kesetimbangan reaksi yang diperlukan pada penelitian ini diperoleh dari literatur (Danckwertz, 1970; Kohl and Riesenfeld,1985; dan Treyball, 1981). Pada penelitian ini dipelajari pengaruh laju alir absorben dan konsentrasi K2CO3 dalam larutan absorben masuk terhadap persen penyisihan gas CO2. Deviasi antara hasil prediksi simulasi dan data percobaan pada penelitian ini dibawah 10% untuk laju alir absorben dari 3 sampai dengan 5 liter/menit dan untuk laju alir 5 sampai dengan 7 liter menit deviasi nya antara 10-30%.Kata kunci: perpindahan massa, eddy diffusivity, absorpsi, non-isotermal, packed column

Pengaruh Ukuran Partikel Arang Sekam Padi Dan Waktu Refluks terhadap Kadar Abudan Daya Serap Karbon Sekam Padi

The highest content in rice husk is ash with its main component of silica. Silica in ash causes the low adsorption capacity. Activated carbon from rice husk can be obtained by lowering the ash content. The aim of this study is determine the effect of particle size of charcoal and reflux time the ash content using a solution of potassium carbonate. The activation of rice husk char was carried out by using reflux methods with a potassium carbonate solution. The resulted carbon was washed using hydrochloric acid tested using iodine and methylene blue to examine of its adsorbance. The particle size of rice husk and reflux time decrease ash content in rice husk. In general, husk with the size of 80 mesh can produce carbon with low ash content and high absorption using reflux time at least for 120 minutes. Rice husk size of 100 mesh refluxing with potassium carbonate for 150 minutes can reduce the ash content as 91.85% and adsorptivity of the iodine at 331 mg.g -1 .