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What is a unit operation?

A fundamental step in an industrial process transforming flows of mass, energy, and information.

 Name three components of an industrial site.

Raw material pipelines, auxiliary utility flows, and data transfer networks.

What are three types of process diagrams used?

Block Flow Diagram (BFD), Process Flow Diagram (PFD), Piping and Instrumentation Diagram (P&ID).

What is the phase rule for degrees of freedom in flows?

F = 2 - π + N + 1

List five types of unit operations.

Transport, Storage, Mixing, Separation, Chemical Conversion

 What drives physical adjustments like heating or pumping?

Thermal gradients, mechanical forces, or electromagnetic forces.

What are the four main treatment levels in WWTPs?

Primary (mechanical), Secondary (biological), Tertiary, Quaternary.

What is the role of sludge treatment?

To reduce volume and remove harmful components before disposal or reuse

What are the main sources of drinking water?

 Groundwater, surface water, seawater.

What is the final step in preparing drinking water from seawater?

Membrane purification (reverse osmosis)

When was the first oil refinery built?

1881 by Alfred Nobel

What does API gravity measure?

The density of crude oil relative to water

What is the Watson Characterization Factor used for?

To indicate the paraffinic or aromatic nature of crude oil.

What is a topping refinery?

A basic refinery that performs atmospheric distillation

What is the purpose of a hydrotreater?

To remove sulfur and nitrogen from hydrocarbon streams.

What is chemical equilibrium?

A state where the rate of the forward reaction equals the rate of the reverse reaction

State Raoult’s Law

The partial vapor pressure of a component in a mixture is proportional to its mole fraction

 What is the purpose of trays in a distillation column?

To create contact stages for mass transfer between vapor and liquid phases.

How do you calculate the number of trays needed?

Using an x-y diagram, stepping between equilibrium and operating lines.

What is the main focus of petrochemistry?

Processing intermediate refinery products into useful chemicals.

 List five types of organic reactions.

Substitution, Addition, Condensation, Elimination, Isomerization.

What is the function of a steam cracker?

To break down hydrocarbons into smaller, more valuable molecules like ethylene and propylene.

What is a key constraint when balancing equations in integer form?

Variables must be whole numbers, often found using linear algebra.

Define reaction rate.

The change in concentration of a reactant or product per unit time

What are the three main types of reactors?

Batch Reactor, Continuous Stirred Tank Reactor (CSTR), Plug Flow Reactor (PFR)

 Why is process control essential?

To maintain desired operating conditions and ensure safe, efficient operation.

What are the three basic components of a control system?

Sensor, Controller, Actuator.

What are the key steps in sugar refining?

Washing, cutting, extraction, coagulation, filtration, crystallization, drying

What is the main reaction in biodiesel production?

Base-catalyzed transesterification of fats/oils with methanol.

What is a key difference between batch and continuous processes?

Batch processes are time-dependent and discrete; continuous processes are steady and ongoing

When are batch processes preferred?

For small-scale, flexible, or seasonal production like pharmaceuticals or specialty foods.

What are the two main output streams from a distillation column?

The distillate (top product) and the bottom product.

What is the reflux ratio (R) in distillation?

The ratio of the liquid returned to the column to the distillate withdrawn.

How does a higher reflux ratio affect separation?

It generally improves separation but increases energy usage.

What is the role of sieve trays in a distillation column?

To enhance contact between vapor rising and liquid descending.

Where is the feed stream introduced in a distillation column?

At an intermediate point, creating rectifying and stripping sections

What is the mole fraction of the lightest component in the feed called?

zFz_F

 What does the x-axis represent in the x-y diagram?

 Mole fraction in the liquid phase.

What does the y-axis represent in the x-y diagram?

 Mole fraction in the vapor phase

How do you determine the number of equilibrium trays graphically?

 By stepping between the equilibrium curve and operating lines.

What is the function of the condenser at the top of the column?

It condenses the vapor stream to form liquid reflux and distillate

What is the q-line in distillation?

 A line that represents the thermal condition of the feed.

What is the main equation for the distillate mass balance?

 VyD=LxD+DxDVy_D = Lx_D + Dx_D

 What happens at the reboiler?

 Part of the bottom liquid is vaporized and returned to the column.

What is the significance of the intersection point of operating lines and feed line?

 It ensures all mass balances are satisfied.

What is xDx_D?

 Mole fraction of the lightest component in the distillate

What is xBx_B?

 Mole fraction of the lightest component in the bottom product.

Why is condensation needed at the top?

To recycle part of the liquid as reflux for better separation.

Why must trays operate at equilibrium?

To maximize the efficiency of component separation.

What does increasing the number of trays do?

Improves separation performance

What does the feed composition determine in design?

The required operating conditions and number of trays.

 What is the core discipline at the heart of (petro)chemistry?

Organic chemistry

Name five product groups made by (petro)chemical industry.

Solvents, resins, fragrances, pharmaceuticals, adhesives.

What are the five main base chains in (petro)chemistry?

C1 (methane), C2 (ethylene), C3 (propylene), C4 (butenes), BTX (aromatics).

 What is a steam cracker?

 A unit that converts hydrocarbons into smaller valuable components.

 What reaction converts alkanes to alkenes?

Dehydrogenation

What reaction forms aromatics from cyclic structures?

Dehydrocyclization

What is dealkylation?

 Removal of side chains from aromatics

Why is steam used in steam cracking?

 To minimize soot and aid reaction control.

What does radical polymerization form?

 Long-chain polymers from small unsaturated molecules.

 What is the key input for steam crackers in Europe?

Naphtha

 What happens immediately after steam cracking?

Rapid quenching to prevent secondary reactions.

What are common products of steam cracking?

 Ethylene, propylene, butadiene, aromatics.

 What is substitution in organic reactions?

One atom or group replaces another

What is an elimination reaction?

Formation of a double bond by removing atoms.

 What are BTX compounds?

Benzene, Toluene, Xylene

 How are C1–C4 base chains categorized?

 By number of carbon atoms and structure.

What is cracking in steam crackers?

Breaking long hydrocarbons into smaller ones.

Where are Dutch steam crackers located?

Moerdijk, Terneuzen, Geleen.

 What are major reaction types in petrochemistry?

 Substitution, addition, condensation, elimination, isomerization.

What is the difference between refining and (petro)chemistry?

Refining focuses on separation, petrochemistry on transformation.

 What is the general formula for a reaction rate?

 Rate = (1/stoichiometric coefficient) × d[concentration]/dt

What causes a runaway reaction?

Exothermic feedback loop due to insufficient cooling

What does the Arrhenius equation relate?

Reaction rate to temperature.

 What is the effect of a catalyst?

 Lowers activation energy, increasing reaction rate.

 What is a batch reactor?

A closed vessel where reactants react over time.

What is a CSTR?

A reactor where contents are continuously stirred and fed.

What is a PFR?

 A reactor where flow is unidirectional with no back-mixing.

What is the mole balance equation?

 Accumulation = Inflow - Outflow + Formation

What are parallel reactions?

Reactions that occur simultaneously with different products.

How is concentration related to reaction rate?

 Higher concentration generally increases the rate.

What effect does pressure have in gas reactions?

Similar to increasing concentration

What is residence time in a PFR?

 τ=VR/v˙in\tau = V_R / \dot{v}_{in}

What is the exponential term in the Arrhenius equation?

 e−Ea/RTe^{-E_a/RT}

 What is the rate constant k?

Proportionality constant in reaction rate equations.

 What is used to solve for coefficients in complex reactions?

 Systems of linear equations.

What is the primary goal of balancing chemical equations?

Ensuring mass conservation.

What does increasing temperature by 10°C do to rate?

 Approximately doubles the reaction rate.

What is the impact of incomplete reactions in CSTRs?

 Can lead to temperature spikes and unsafe operation.

 What is the formation term in mole balance?

Change due to chemical reaction.

What is important for reactor design?

Reaction kinetics, residence time, heat transfer.

 What are the three main components of a control loop?

Sensor, controller, actuator.

 What does a sensor do?

Measures a physical quantity

What does a controller do?

Compares measured value with setpoint and calculates correction.

What does an actuator do?

Executes the control action.

What is the goal of process control?

Maintain system at desired operating conditions.

What is a setpoint?

Desired value of a process variable.

What is feedback control?

Correction based on measured deviation from setpoint.

 What is feedforward control?

Anticipates disturbances before they affect the system.

 What does a control valve regulate?

Flow of fluids like steam or coolant.