SECTION A – Short Answer Section
This section contains short conceptual questions related to size reduction, mixing, filtration, drying, corrosion, and basic pharmaceutical engineering principles used in manufacturing processes.
Question 1: Describe Attrition and Impact.
Answer:
Attrition:
Attrition is the process of size reduction caused by friction between particles when they rub against each other.
Impact:
Impact is the size reduction caused when particles are struck by moving objects such as hammers or balls in mills.
Both mechanisms are widely used in pharmaceutical milling operations.
Question 2: Define Entrainment and its Prevention.
Answer:
Entrainment is the carrying away of fine particles of liquid or solid by vapor or gas during evaporation or distillation.
Prevention methods:
Use of entrainment separators
Reducing vapor velocity
Installing baffles or demisters.
Question 3: Define Corrosion and Effect of pH on Corrosion.
Answer:
Corrosion is the gradual destruction of metals due to chemical or electrochemical reactions with the environment.
Effect of pH:
Acidic conditions (low pH) increase corrosion rate.
Neutral or alkaline conditions (high pH) reduce corrosion in many metals.
Corrosion control is important in pharmaceutical equipment and plant construction.
SECTION B – Long Answer Section
This section requires detailed explanations of pharmaceutical engineering equipment such as mills, dryers, and filtration systems used in drug manufacturing.
Question 1: Explain Hammer Mill.
Answer:
Principle:
Hammer mill works on the principle of impact between rapidly moving hammers and the material.
Construction:
A metal chamber containing rotating hammers.
A screen through which smaller particles pass.
Working:
Material enters the mill and is crushed by high-speed rotating hammers. The smaller particles pass through the screen.
Applications:
Grinding of pharmaceutical powders
Size reduction of crude drugs.
Question 2: Explain Freeze Drying (Lyophilization).
Answer:
Freeze drying is a process used to remove water from frozen materials by sublimation under vacuum.
Steps involved:
Freezing of the product
Primary drying (sublimation of ice)
Secondary drying (removal of residual moisture)
Applications:
Preservation of vaccines
Storage of antibiotics
Stabilization of biological products.
Question 3: Explain Plate and Frame Filter Press.
Answer:
Principle:
Filtration occurs due to pressure difference across a filter medium.
Construction:
Alternate plates and frames
Filter cloth placed between them
Hydraulic press for pressure
Working:
Slurry is pumped into the frames. Solid particles remain on filter cloth forming cake, while liquid filtrate passes through.
Applications:
Used for clarification of liquids and separation of solids in pharmaceutical industries.
SECTION C – Descriptive Section
This section tests deeper knowledge of fluid flow, mixing systems, filtration theories, centrifugation, and distillation techniques.
Question 1: Define Centrifugation and Explain its Theory.
Answer:
Centrifugation is the process of separating particles from a liquid by applying centrifugal force.
Theory:
When a mixture rotates at high speed, particles with higher density move outward due to centrifugal force while lighter particles remain closer to the center.
Applications:
Separation of blood components
Clarification of suspensions
Separation of crystals from liquids.
Question 2: Explain Fractional Distillation.
Answer:
Fractional distillation is used to separate liquids with close boiling points.
Principle:
It is based on repeated vaporization and condensation using a fractionating column.
Working:
Mixture is heated in a flask.
Vapors rise through the fractionating column.
Components condense at different temperatures and are collected separately.
Applications:
Separation of solvents
Purification of chemicals in pharmaceutical industries.
Question 3: Types of Stainless Steel and its Uses.
Answer:
Common types of stainless steel used in pharmaceutical industries:
Stainless Steel 304:
Contains chromium and nickel; used for equipment manufacturing.
Stainless Steel 316:
Contains chromium, nickel, and molybdenum; more resistant to corrosion.
Uses:
Pharmaceutical reactors
Storage tanks
Pipes and processing equipment.
