Instrumentation - Design of Plant Components

This set of flashcards covers key vocabulary terms and definitions that are essential for understanding the concepts discussed in the 'Design of Plant Components' section of Instrumentation.

Piping Design

The planning and arrangement of pipes in a chemical plant to ensure efficient fluid transport.

Pressure Drop

The reduction in pressure as a fluid moves through a pipe due to friction and other factors.

Flow Rate

The volume of fluid that passes through a given surface per unit time, typically measured in cubic meters per second (m³/s).

Bernoulli Equation

A principle that relates pressure, velocity, and height in a fluid flow.

Nominal Diameter (DN)

A way to express the diameter of pipes or fittings, standardized across industries for compatibility.

Net Positive Suction Head (NPSH)

The minimum pressure required at the suction port of a pump to avoid cavitation.

Drag Coefficient

A dimensionless number that describes the resistance of an object in a fluid environment, affecting pressure drops in fittings and valves.

Centrifugal Pump

A type of pump that uses rotational energy to move fluids through a system.

Valve Characteristic

The relationship between valve lift and flow rate, which can vary by design (linear, equal percentage).

Laminar Flow

A flow regime characterized by smooth and orderly fluid motion, typically occurring at low velocities.

Turbulent Flow

A chaotic flow regime characterized by irregularities and swirls, typically occurring at high velocities.

Friction Factor

A dimensionless quantity that represents the resistance to flow in pipes due to friction.

Energy Streams

The flow of energy in a system, particularly in relation to mechanical work, fluid motion, and pumps.

Pump Efficiency

The ratio of the useful work performed by a pump to the energy supplied to it.

Drag Coefficient for Valves

A measure of the resistance that valves provide to the flow of fluid, which impacts the pressure drop across the valve.

Flow Control

The process of regulating the flow rate of fluids in piping systems, often achieved through valves.

Piping System Characteristics

The performance attributes of a piping system, including how it responds to varying flow rates and pressure drops.

Cavitation

The formation of vapor bubbles in a fluid, which can occur when the pressure drops to below the fluid's vapor pressure, potentially damaging pumps.

Mechanical Energy Balance

An accounting of energy in a system that considers inputs, outputs, and losses due to friction and other factors.

Pressure Drop in Valves

The additional pressure loss experienced as fluid flows through a valve, influenced by its design and opening.

Continuous Stirred Tank Reactor (CSTR)

A type of reactor where reactants are continuously fed, stirred, and product is continuously removed, often used for level control in process systems.

Bernoulli Equation (Energy Balance Form)

\frac{P1}{\rho} + \frac{v1^2}{2} + g z1 + ws = \frac{P2}{\rho} + \frac{v2^2}{2} + g z2 + F where P is pressure, \rho is density, v is velocity, g is gravity, z is elevation, ws is shaft work per unit mass, and F is friction loss per unit mass.

Darcy-Weisbach Equation for Frictional Head Loss

hf = f \frac{L}{D} \frac{v^2}{2g} where hf is head loss, f is Darcy friction factor, L is pipe length, D is pipe inner diameter, v is average fluid velocity, and g is acceleration due to gravity.

Reynolds Number (Re) Formula

Re = \frac{\rho v D}{\mu} = \frac{v D}{\nu} used to predict flow patterns, where \rho is fluid density, v is velocity, D is characteristic linear dimension (e.g., pipe diameter), \mu is dynamic viscosity, and \nu is kinematic viscosity.

Volumetric Flow Rate (Q)

Q = A v where A is the cross-sectional area of the pipe and v is the average fluid velocity.

Hydraulic Power (P_h) delivered by a pump

P_h = Q \Delta P where Q is the volumetric flow rate and \Delta P is the total pressure increase across the pump.

Mass Flow Rate (\dot{m}) Formula

\dot{m} = \rho Q = \rho A v where \dot{m} is mass flow rate, \rho is fluid density, Q is volumetric flow rate, A is cross-sectional area, and v is average fluid velocity.

Pump Efficiency (\eta) Formula

\eta = \frac{P{out}}{P{in}} = \frac{Q \Delta P}{W{shaft}} where \eta is pump efficiency, P{out} is hydraulic power delivered to the fluid, P{in} is mechanical power input to the pump shaft, Q is volumetric flow rate, \Delta P is pressure increase across the pump, and W{shaft} is actual shaft work input.

Minor Losses (Fittings/Valves) Formula

hL = K \frac{v^2}{2g} where hL is the minor head loss, K is the loss coefficient (specific to the fitting/valve), v is the average fluid velocity in the pipe, and g is acceleration due to gravity. This accounts for losses due to changes in flow direction or cross-section.

Net Positive Suction Head Available (NPSH_A) Formula

NPSHA = \frac{P{atm}}{\rho g} + \frac{P{static}}{\rho g} - hf - \frac{P{vap}}{\rho g} Where P{atm} is atmospheric pressure, P{static} is static head (e.g., from tank level), hf is frictional head loss in suction line, P{vap} is vapor pressure of the fluid, \rho is fluid density, and g is acceleration due to gravity. NPSHA must be greater than NPSH_R (required) to prevent cavitation.