Transcript EDPS - Chemistry

Introduction to
Process Technology
Unit 5
Applied Chemistry
Agenda
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Organic and Inorganic
Chemical and Physical Properties
Terminology
Reactions
Chemical Formulas, Calculating Mass
Acid, Base, pH
Hydrocarbons
Other chemical families
Review
Chemistry in Process Industry
• How Chemistry Applies to Process Tech
– Turning raw materials into products
– Proper management of waste
– Understand chemistry concepts that occur
during manufacturing process
– Understand terminology
– Understand concepts to troubleshoot
problems and improve quality, efficiency
Structure of Matter
• Atoms – smallest particle of an element that retains the
properties of that element
– Protons – positively charged subatomic particle
found in the nucleus of an atom
– Neutrons – subatomic particle found in the nucleus
of an atom that has no charge
– Electrons – negatively charged subatomic particle
found in orbiting the nucleus of an atom
-- Valence Electrons – outermost electrons which
provide links for bonding
• Ions – charged particles
– Anion – atom or group of atoms with
negative charge
– Cation - atom or group of atoms with
positive charge
• Molecule – neutral chemically bonded
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groups of atoms that act as a unit
Isotope – element that has same
number of protons but different number
of neutrons
Structure of Matter (Continued)
• Atomic Number – the number of protons in the
nucleus of an atom of an element
• Atomic Mass (Molecular Weight) – weighted
average of the masses of the isotopes of an element
predominantly from masses of protons & neutrons
• Determining Molecular Weight –
– Add all masses of each element. Remember to
multiply if more than 1 present.
Organic and Inorganic
• Chemistry – science that deals with the composition,
behavior, and transformation of matter
• Organic – carbon based
– Hydrocarbon – contains only hydrogen and carbon
• Inorganic – no carbons
– Such as salts, acids, bases, metals
– Many agricultural products
Physical Properties
• Density – mass (weight) per unit volume
• Specific Gravity – comparison of density to that of
water for solids and liquids and to air for gases
• Hardness – ability of one substance to scratch/mark
another
• Odor – smell of substance
• Color – optical sensation produced by effect of light
waves stiking surface
Reactivity of a Chemical
• The ability of a substance to form new
substances under given conditions
• A listing of all chemical reactions of a
substance and the conditions under which
the reactions can occur
Types of Bonds
• Ionic – metal and non-metal. Electrons
are transferred
• Covalent – non-metals. Electrons are
shared
• Metallic – metal to metal. Electrons free
flow
Terminology
• Matter – anything occupying space that has mass
• Element – simplest form of matter
• Compound – pure substance made up of elements
that are chemically combined
• Mixture - mixed together, but no chemical reaction
• Solution - a homogenous mixture of 2 or more substances in
a single phase (usually liquid). Solute and solvent.
Terminology (Continued)
• Solvent – substance that dissolves
• Solute – substance that is dissolved
– Solubility : how well solvent dissolves the
solute
– Insoluable: solute will not dissolve in the
solvent
• Freezing Point – temp. to change liquid to solid
• Melting Point – temp. to change solid to liquid
Terminology (Continued)
• Boiling Point
– When vapor pressure of liquid equals
system pressure
– As vapor pressure increases, boiling point
decreases
– As system pressure increases, so does
boiling point
– The higher the vapor pressure the more
easily a material evaporates
Terminology (Continued)
• Homogenous
– Same throughout
– Can’t tell one part of mixture from another
• Heterogeneous
– Different
• Equilibrium
– Rate of reactants forming products = rate of
products forming reactants
Chemical Reactions
• Chemical Reactions
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Endothermic – needs/absorbs heat
Exothermic – gives off heat
Neutralization – acid + base
salt + water
Combustion –
• fuel + oxygen
combustion products + energy + light
– Replacement – removes minerals from water
Chemical Reactions are
Affected By
• Heat --- increases molecular activity and
reaction rate (rates double with each 10°)
• Pressure – slows molecular movement and
changes boiling point
• Surface Area – solids
• Concentration of liquid and gas
components
• Flow Rates of reactants and products
Chemical Reactions
• Catalyst
– Helps a reaction start, go at a lower temp,
or increases rate of reaction
– Is not consumed in the reaction
Types of Catalysts
• Adsorption – solid that attracts and holds
reactant molecules so more collisions
can occur. Also stretches bonds of
reactants making them easier to break,
which requires less energy.
Types of Catalysts
• Intermediate – attaches to reactant
molecules and slows it down so
collisions can occur
• Inhibitor – decreases reaction rate
• Poisoned / Spent – no longer functions
due to contamination or has been used
up
– Some can be regenerated
Chemical Equations
• Like a recipe
• Must be balanced (same number of
atoms of each element in reactants as
products
2H2 + O2
2H2O
reactants
products
Mass Relationships
• Allows us to take a balanced equation
and use it to determine the actual
mass/weight needed for reactants and
how much product can be produced
Mass Relationships - Steps
• Find molecular weight of each element on
periodic table (AMUs, but represent grams,
pounds, etc.)
– Example H = 1.008 O = 16.00
• Multiply by number of atoms (if > 1)
– Example
H x 2 = 2.016
• Total these up to determine actual weight of
entire molecule
– Example H2O = 2.016 + 16.00 = 18.016
• Note how reactant mass = product mass
Mass Relationships - Steps
• Determine how many moles (amounts) of
a reactant are needed to produce a set
amount of product
– Example
N2 + 2O2  2NO2
– So you need 1 mole of N2 and 2 moles of O2 to
make 2 moles of NO2
Mass Relationships - Steps
• Determine the relative volume of
reactant or product you have
– Example if you only have 16 pounds of O, you
only have 0.25 volume (16/64)
• Multiply the relative volume by the
amount of product you can make
– Example – 0.25 x 2NO2 = 0.5 volume of NO2
Mass Relationships - Steps
• Multiple the volume you can make by the
molecular weight of material
– Example – 0.5 volume x 46 * = 23 kg, lbs, tons
N=
14.00 kg, lbs, tons
O = 16.00 x 2 = 32.00 kg, lbs, tons
* 46.00 kg, lbs, tons
Material Balances
• Method used to determine the exact
amount of reactants needed to produce the
specified products in the quantity desired
• Steps
– Determine the weight of each molecule
– Ensure reactant total weight equals product
total weight
– Determine relative number of reactant atoms
or ions
Percent by Weight Solutions
• Weight of solute (material that is
dissolved) is taken in relationship to
entire solution
• 650 pound barrel has 10% catalyst
solution
– 650 lb x 0.10 (percent as decimal) = 65 lbs
Acid, Base and pH
• pH – measurement of hydrogen ions in solution
• Acid (pH > 0 and < 7)
– Sour taste
– Vinegar, Hydrocholoric Acid, Hydrofluoric Acid
• Base (pH > 7 and < 14)
– Bitter taste, slippery
• Alkaline
• Caustic –pungent odors
– Lye, sodium hydroxide, caustic soda
• Neutral – pH = 7
• The stronger the acid or base the more hazardous to
body tissue and metal
Hydrocarbons
• Compound that contains both hydrogen
and carbon
• Fossil fuels – oil & natural gas, and their
refined products (gasoline, ethylene)
Hydrocarbons
• Major groups
– Alkanes – single covalent bond (methane, propane,
ethane, etc)
– Olefins – not naturally occurring. Produced by
cracking oil. At least one double bond (hence the
high energy when used)
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Alkenes – double bonds (ethylene, propylene)
Alkyne – triple bonds (acetylene – only one used widely)
Cycloalkane – contains a ring or cycle of carbons
Aromatic – contains at least one highly unsaturated sixcarbon ring
Aromatic Hydrocarbons
• Include both hydrocarbons and
compounds that cannot be classified as
hydrocarbons
• Most common - benzene
Alcohols
• Compounds that contain OH goups
connected to an alkyl carbon.
– Ethanol – commonly referred to as grain
alcohol since often produced from corn, rye,
wheat, molasses (from sugar cane), grapes
and potatoes.
• Becoming popular as gasoline additive or main
fuel.
Alcohols
• Methanol – referred to as wood alcohol,
because it was originally derived from
wood.
– Now produced by subjecting H to CO3 at high
temp. in presence of catalyst.
– Used as solvent in paints, varnishes,
production of formaldehyde, cleaners.
Alcohols
• Isopropyl Alcohol – most common is
rubbing alcohol used externally for
cooling skin, disinfect cuts, cosmetic
solvent
Phenols
• Similar to alcohols, but have an OH group
connected directly to an aromatic ring.
• Used in antiseptics, dyes, aspirin, and at
one time throat lozenges
Ethylene Glycol
• Highly reactive ethylene oxide is reacted with water
• Commonly used as antifreeze in vehicle radiators
because of unique abiltiy to lower freezing point of
water.
• Also has higher boiling point than water so better
suited to high and low temp. variations due weather
extremes.
• Because of toxicity when ingested there is a move to
switch to less toxic propylene glycol – which many
countries in Europe have already done
Applied Concepts
• Distillation – separation of various
fractions in a mixture by individual
boiling points
• Reactors – designed to break or make
chemical bonds which changes
reactants into products
Applied Concepts
• Catalytic Cracking – splits side stream of
fractionating column into smaller, more
useful molecules – for example, kerosene
into hexane and hexene
• Hydrocracking – process used to boost
gasoline yield
• Alkylation – uses a reactor to make one
large molecule out of smaller ones. For
example isobutane and olefins into high
octane alkylates
Review
• List importance of applied chemistry to
process technicians
• Re-write all vocabulary words and their
definitions
• Understand difference between the following:
– Organic and inorganic
– Endothermic and exothermic
– Acids and bases
• Define the 4 basic chemical reactions most
common to process industry
Work
• Read CAPT Chapter 11 (pages 158 – 169)
– Do questions 1 – 13 on pages 170 & 171)
• Read Thomas Chapter 13 (pages 281 – 302
– Do questions 1 – 21 on page 303
• Module 5, Exercise 1 – Chemistry Supplement
• Major Grade
• In class example worked by group
Independent Project
• Internet or literature search
• Write a paper on the importance of chemistry
to 2 different process industries
• List raw materials, products
• List what chemical reactions, terms apply
• Identify associated safety and environmental
measures and/or concerns