CPI MODULE 1

Chemical Process Industries

Raw materials undergo chemical conversion during their processing into finished products, as well as the physical conversions common to industry in general.

Interdependent Principles:

Mass and Energy Balances

Thermodynamics and Kinetics

Unit Operations and Chemical Reactions

Instrumentation and control

Economics

Chemical Conversions

Combustion, Calcination, Cracking/Pyrolysis, Dehydrogenation, Halogenation, Hydrolysis, Oxidation, Polymerization, Reduction

Combustion

This involves the burning of a fuel and oxidant to produce heat and/or work.

Calcination

The process of heating a substance to a high temperature but below the melting or fusing point, causing loss of moisture, reduction or oxidation, and dissociation into simpler substances

Cracking or Pyrolysis

thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible.

Dehydrogenation

This is a reaction in which hydrogen is detached from a molecule. The reaction is strongly endothermic, and therefore heat must be supplied to maintain the reaction temperature. (used in the manufacture of synthetic rubber)

Halogenation

A chemical reaction or process which results in the formation of a chemical bond between a halogen atom and another atom. (used in themanufacture of organic chemicals)

Hydrolysis

A chemical reaction in which water is used to break down a compound; this is achieved by breaking a covalent bond in the compound byinserting a water molecule across the bond (used in the manufacture of organic chemicals)

Oxidation

This is a chemical reaction involving the addition of oxygen, the removal of hydrogen, or the removal of an electron from a substance. (used in themanufacture of organic chemicals)

Polymerization

A chemical reaction in which two or more molecules combine to form larger molecules that contain repeating structural units (used in themanufacture of plastics, elastomers and synthetic rubbers)

Reduction

This is the complete transfer of one or more electrons to a molecular entity (also called "electronation"),

Reduction

the reverse of the processes described under oxidation (used in polymer catalyst manufacture)

Physical Conversions

Distillation, Filtration, Adsorption, Diffusion, Crystallization

Distillation

This is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture.

Filtration

The mechanical or physical operation which is used for the separation of solids from fluids (liquids or gases) by interposing a medium through which only the fluid can pass.

Adsorption

This is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface.

Diffusion

The spread of particles through random motion from regions of higher concentration to regions of lower concentration.

Crystallization

Crystallization is the (natural or artificial) process for the formation of solid crystals from a uniform solution. Crystallization is in general the last chemical purification step in the production of ingredients.

FUNCTIONAL AREAS/ FIELDS OF CHEMICAL ENGINEERING

Process, Production, Maintenance, Administration, Design, Consultancy, Project Management, Research and Development, Product Engineering, Education, Environmental Engineering, Quality Control, Others

Chemistry

basic science on which chemical industries rest

Yield

the fraction of the raw material recovered as the main (desired) product

The goal of the chemical engineer is…

to have the conversion equal to the yield

Conversion

the fraction changed to something else (by – products)

Kinetics

the study of reaction speeds

Material Balance

a study showing the origin the ultimate disposition of all materials used, is an essential first step in any processing study.

Thermodynamics

is widely used for providing useful data on all phases of technical reactions

BATCH

all mass is charged to the process and nothing is withdrawn until the operation is complete

BATCH

usually for small-scale processing, more expensive, tendency of producing non-uniform products.

CONTINUOUS

the input and output streams are flows that move continuously through the equipment

CONTINUOUS

large-scale processing, less expensive, uniformity of products may be maintained.

FLOWCHARTS

a set of boxes interconnected to one another by arrows to show the flow of steps involved in the conversion of raw materials into finished products.

Types of Flowcharts

Rough-block diagram (simple)

Complex-flow diagram

Rough-block diagram (simple)

for the purpose of studying the process, often show only material and energy flows and operating conditions

Complex-flow diagram

for actual plant construction, show such details as fire lines, instruments and control systems, air lines, drains, etc.

Process Engineer

a specialist in current aspects of chemical process design

Factors to consider in planning a plant

Pilot plant

Equipment

Corrosion, Materials of Construction

Automatic and instrument

Pilot plant

a small-scale unit designed to allow experiments that obtain design data for larger plants and sometimes to produce significant quantities of a new product to permit user evaluation.

Instruments

their function is to assure consistent quality, usually by sensing, controlling, recording, and maintaining desired operating conditions.

Instrument types:

Indicating instruments, Recording instruments, Indicating/recording and controlling instruments

Analog instruments

show results by mechanical movement of some type of device which is proportional to the quantity being measured

Digital devices

utilize a “transducer”

transducer

a device to convert the quantity being measured into some type of signal.

Engineers are distinguished from scientists by their consciousness of _____ and _______.

costs, profits

Competing Processes

Different technical process are available in the production of a certain product, choosing the one from among many that is best for a particular location or time is an economic decision.

Material Balances

Yields and conversions of the chemical process form the basis for the _________ __________, which in turn are the foundation for cost determination.

Energy

is frequently a major cost in chemical plants, but it is often possible to reduce energy use by altering processing procedures.

Labor

Skilled operators contribute as much to a plant’s success as excellence in design. The chemical process industries have moved rapidly into labor – saving techniques

The single largest cost is usually ___ ________, with energy, labor, overhead, and depreciation all being significant.

raw material

Purity and Uniformity of Product

The physical condition of the products has a great influence on marketability

Packaging

are expensive and should be avoided whenever possible.

Sales and Customer Service

form the major contact between buyer and seller.

Prudent and proper location for a chemical plant is determined largely by:

Availability of raw materials, Energy, Transportation, Markets, Environmental constraints, Water supply, Availability of efficient labor, Cost of Land, Waste disposal facilities

Nothing is so destructive to a plant as ____.

Fire

3 types of standards (safety)

Initial standards

Emergency temporary standards

Permanent standards

Emergency temporary standards

issued to protect employees from serious danger from toxic or harmful substances or from new hazards

Permanent standards

can be set only after formal proceedings where interested persons have a chance to submit their views and objections

Patents

A form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention.

Patents

provides the right to exclude others from making, using, selling, offering for sale, or importing the patented invention for the term of the patent, which is usually 20 years from the filing date