(SEM III) THEORY EXAMINATION 2022-23 PHARMACEUTICAL ENGINEERING

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.