Module 2 – Mechanical & Instrumentation Basics

Objective:
By the end of this module, a trainee will be able to:

1. Understand the basic mechanical equipment used in petrochemical plants.

2. Recognize the purpose and function of pumps, compressors, valves, heat exchangers, and strainers.

3. Understand basic instrumentation concepts and operator interfaces.

4. Learn safe operating practices and observation tips for mechanical equipment.

2.1 – Introduction to Mechanical Equipment

Definition:

• Mechanical equipment in a petrochemical plant transports, compresses, heats, cools, and separates chemicals.

• Operators must understand how equipment works conceptually, safety concerns, and basic troubleshooting methods.

Key Principles:

1. Energy Transfer: Equipment moves or converts energy (mechanical, thermal, pressure).

2. Flow Control: Valves and instruments control flow, level, and pressure.

3. Safety First: Mechanical failure can lead to leaks, fire, or explosions.

2.2 – Pumps

Purpose:

• Pumps are used to move liquids from one location to another.

Types:

1. Centrifugal Pump:

   • Uses rotating impeller to increase liquid velocity.

   • Common for low-viscosity fluids.

2. Positive Displacement Pump:

   • Moves a fixed amount of fluid per rotation.

   • Used for viscous liquids or precise flow control.

Basic Operating Concepts:

• Pumps may be standby or duty pumps; operators may switch pumps to balance usage.

• Monitoring: flow rate, pressure differential, vibration, noise.

• Observation Tips: unusual noise or vibration may indicate cavitation or blockage.

Safety Notes:

• Never run a pump dry (no liquid).

• Ensure suction and discharge valves are in the correct position before start.

Analogy for Beginners:

• Centrifugal pump = a spinning waterwheel pushing water forward.

• Positive displacement pump = a piston pushing fixed volume of water through a pipe.

2.3 – Compressors

Purpose:

• Compressors increase the pressure of gases for transport or reaction.

Types (Basic Conceptual):

1. Centrifugal Compressor: Uses a rotating impeller.

2. Reciprocating Compressor: Uses pistons to compress gas.

3. Rotary Screw or Lobe Compressor: Uses meshing rotors.

Basic Operation Concepts:

• Monitor suction/discharge pressure, temperature, lubrication.

• Ensure no vibration or abnormal noise.

• Use standby compressors to allow maintenance without shutdown.

Safety Notes:

• Gas compression creates heat; cooling and lubrication are critical.

• Always follow ESD (Emergency Shutdown) procedures in abnormal situations.

2.4 – Valves & Actuators

Purpose:

• Valves control flow, pressure, and level of fluids or gases.

• Actuators automate valve movement.

Common Valve Types:

• Gate Valve

On/off flow

Isolate a line

• Globe Valve

Flow control

Adjusting flow to reactor

• Check Valve

Prevent backflow

Pump discharge line

• Control Valve

Automated regulation

Maintaining pressure or flow

• Ball Valve

Quick on/off

Emergency isolation

• Butterfly Valve

Large flow, fast operation

Cooling water lines

Actuators:

• Pneumatic, electric, or hydraulic devices that operate valves automatically.

Observation Tips for Operators:

• Verify valve position matches control panel indication.

• Look for leaks or unusual vibrations around actuators.

Analogy for Beginners:

• Valves = faucets, controlling flow of water (or chemical) through the pipes.

2.5 – Heat Exchangers & Cooling Systems

Purpose:

• Heat exchangers transfer heat between two fluids without mixing them.

• Cooling systems remove heat to maintain safe process temperatures.

Common Types:

• Shell & tube

• Plate-type

• Air-cooled

Operator Concepts:

• Monitor inlet/outlet temperatures and pressure drop.

• Signs of fouling: reduced heat transfer, higher pressure drop, unusual noise.

• Routine maintenance: tube cleaning, checking gaskets, monitoring leaks.

Safety Notes:

• Never open a heat exchanger under pressure or high temperature.

• Wear PPE when inspecting for leaks or cleaning.

Analogy for Beginners:

• Like a radiator in a car: hot water flows in one side, cooler air or water removes heat.

2.6 – Strainers & Filters

Purpose:

• Strainers remove solid particles from fluids to protect pumps, compressors, and valves.

Operator Concepts:

• Inspect regularly for clogging.

• Clean manually or via backwash depending on design.

• Monitor pressure drop across the strainer: high differential = blocked strainer.

Safety Notes:

• Ensure system is depressurized before opening strainer.

• Follow LOTO procedures if maintenance required.

Analogy for Beginners:

• Strainer = a tea strainer catching leaves while letting liquid pass.

2.7 – Refrigeration / Cryogenic Systems (Conceptual)

Purpose:

• Used to cool process streams or liquefy gases in butadiene and other petrochemical plants.

Basic Concepts:

• Coolant circulates in a closed loop.

• Refrigeration removes heat from process fluid.

• Operators monitor temperature, pressure, and flow.

Safety Notes:

• Low temperature can cause frostbite or brittle fractures.

• Pressure relief systems must be functional.

Analogy for Beginners:

• Like a home refrigerator, but on a much larger scale and with industrial chemicals.

2.8 – Instrumentation Basics

Definition:

• Instrumentation measures, monitors, and controls process variables like temperature, pressure, level, and flow.

Common Instruments:

• Pressure gauge for Monitor line pressure

Check for abnormal high/low readings

• Thermocouple / RTD for Measure temperature

Trend over time

• Flow meter for Measure fluid flow

Compare with expected value

• Level sensor for Detect tank level

Avoid overfill or dry-run

• Alarm / Indicator for Warn of abnormal condition

Respond according to SOP

Operator Concepts:

• Always verify instruments are reading plausibly.

• Learn to distinguish normal fluctuations from abnormal trends.

• Understand interlock function: alarms can prevent unsafe operation.

Analogy for Beginners:

• Instruments = “sensors in your car” (speedometer, fuel gauge, engine temp).

2.9 – Safe Observation & Basic Troubleshooting Tips

1. Listen and Observe: unusual noise, vibration, leak, smell, or color change.

2. Check Panels & Alarms: do not ignore any abnormal indication.

3. Compare Trends: flow, temperature, and pressure changes can indicate problems early.

4. Follow SOPs & Notify Supervisor: don’t attempt repairs beyond operator scope.

Analogy:

• Operator acts like a “mechanical doctor”: detects early symptoms before they become serious problems.

2.10 – Quiz / Knowledge Check

1. Name two types of pumps and explain when each is used.

2. List three common types of valves and their function.

3. What is the main purpose of a heat exchanger?

4. Why must strainers be checked regularly?

5. Give two key observations an operator should make on mechanical equipment.

6. Name four process variables measured by instruments in a plant.

2.11 – Media Sites Integration

• Video Tutorials:

  • Demonstration of pump operation (duty vs standby).

  • Valve operation & actuator animation.

  • Strainer cleaning demo (generic).

  • Conceptual animation of refrigeration cycle.

• Diagrams / Infographics:

  • PFD showing pumps, compressors, valves, heat exchangers.

  • Instrumentation layout on panels.

• PDF Downloads:

  • Checklist for pump, compressor, and heat exchanger observation.

  • Valve operation and safety checklist.

• Interactive:

  • Embedded quizzes and reflection questions.

2.12 – Summary & Key Takeaways

1. Mechanical equipment moves, compresses, heats, cools, or separates chemicals.

2. Pumps, compressors, valves, heat exchangers, and strainers are core equipment for operators.

3. Observation of mechanical equipment, instrument readings, and alarms is critical.

4. Always follow safety practices, SOPs, and report abnormal conditions.

5. Basic understanding of instrumentation helps operators monitor plant performance safely.