February 22, 2024

# Construction of drying curves (for calcium carbonate and starch)

## Construction of drying curves (for calcium carbonate and starch)

### AIM:

To determine the construction of the drying curve for calcium carbonate.

### REQUIREMENTS:

• Petri dish
• hot air oven
• calcium carbonate
• weighing balance
• spatula

### PRINCIPLE:

To behaviour of drying of solid is explained by the drying curve. The time required for drying a batch of the weight of martial in dry air can be estimated with the help of the drying curve.

Drying is a mass transfer process consisting of the removal of water or another solvent by evaporations from a solid, semisolid or liquid. This process is obtained and used as the final production step before, packing products.

### PROCEDURE:

• Take a clean Petri dish without a Lid and consider its weight as W1gm
• Note the area of the Petri dish
• Take 10gm calcium carbonate in a clean Petri dish and consider its weight as W2 gm
• Prepare slurry by adding water consider its weight as W3 gm
• Heat Petri dish in a hot air oven at a temperature of 70°C
• Note down the weight of the sample after every 15 minutes.
• Continue drying until there is no change in weight of the sample is obtained
• Determine percentage moisture content and drying rate by using the following formula

Percentage moisture = W3-W2/W3-W1 × 100

Drying content =W3-W2/area of Petri dish ×100

### REPORT:

• The construction of drying curves of calcium carbonate was determined
• The percentage moisture content is =

### Calculation:

• Weight of empty Petri dish (w1) gm =
• Weight of empty Petri dish + sample (w2) gm =
• Weight of empty petridish + sample + water (w3) gm = Weight of empty petridish + sample + water + (w4) gm = (After drying at different time interval)
• MC1 (moisture content at 0 time) =
• MC2 (moisture content at 15 minutes time) =
• Average moisture content =
• Rate of drying =

Pharm Engg Chapterwise MCQ: UNIT-I MCQ * Flow of fluids * Size reduction * Size separation UNIT-II MCQ *Heat transfer *Distillation *Evaporation UNIT-III MCQ *Drying * Mixing UNIT-IV MCQ * Filtration * Centrifugation * UNIT-V MCQ Materials of construction * Corrosion