Chemical Engineering
Summer@Brown2012
Announcements
• Ethics of Synthetic Biology Paragraph Due Today– Please email to [email protected] by the end
of the day.• Bridge Competition will take place Friday,
August 10 at 9 am in CIT 219.
Overview
• What is Chemical Engineering?• Mass Balance Problems• Case Study: High Fructose Corn Syrup• Lab Tour
Two types of chemical engineers
• Chemical “Process” Engineers– Design, manufacture and operate
plants and machinery on industrial scale
• Chemical “Product” Engineers– Develop or improve large-scale
production of various products
Scaling-up Production Process
• Ammonia Production• Haber Process– 3H2(g) + N2(g) 2NH3(s) (DH = -92.22 kJ/mol)
Fertilizer Plant produces 760,000 tonnes of ammonia each year.
Chemistry vs. Chemical Engineering
How are they different?• Chemists: Design new molecules
and synthesizes new formulas– Small scale: Work in grams of
materials
• Chemical Engineers: Design equipment and processes for large-scale chemical manufacturing– Large scale: Work in tonnes of
materials
What is Chemical Engineering?
• A. Designing a landfill• B. Testing a large scale mixing blade for mixing
bread dough• C. Designing a new chemical formulation for a
fertilizer• D. Planning an assembly line for lithium ion
batteries
All of the above except for C
What is Chemical Engineering?
Basic sciences PLUS engineering fundamentalsTwo Main Goals:
• Convert raw materials into valuable products• Design and manufacture devices
Tools of the Trade:• Chemical reactions (making and breaking of bonds)• Catalysis (accelerating chemical reactions)• Separation, purification of complex chemical mixtures
Goal 1: Convert Raw Materials into Valuable Products
• Crude Oil Gasoline, Jet Fuel, Monomers
• Monomers Polymers (ethylene polyethylene) Plastics
• Silicon crystals Semiconductors, integrated circuits
• Inorganic Precursors Ceramics• Corn Starch High Fructose Corn
Syrup
Goal 2: Design and Manufacture Devices
• Novel materials processes – Kevlar, Gore-Tex, Carbon
fiber, Spider silk• Energy devices – Li ion batteries, fuel cells,
solar devices• Waste treatment
solutions– Treating septic waste, oil
spills
August 28, 1859 - Titusville, Pennsylvania
Lubbock, Texas
Oil Refinement: The start of Chemical Engineering
Large Scale ProductionHaifa, Israel - Oil Refinery
9 million tons (66 million barrels) of crude oil/ year
Chemical Engineering; In a Modern World
How Chemical Engineering is Affecting our World Today
• Fuel– Creating and stretching supplies of fossil fuels
• Cleaner Energy – Non-petroleum energy supply
• Lithium ion batteries,• Solar panels• Nuclear
• “Plastics make it possible” – creating plastics for EVERYTHING. Bottles, bags, styrofoam,
clothing, medical devices….. – And now plastics made from plant starch (bio degradable)
Plastic Continent
How Chemical Engineering is Affecting our World Today
• Large Scale Production– making products and materials more
efficiently for a growing population (diapers, laundry detergent, tires)
• Convenient and abundant food– Processing it more efficiently
• Powering Computers – Innovating materials for computer parts to
make them work better and faster– Computer chips, to thin film liquid crystal
displays• Healing Diseases & Extending life
– Large scale production of penicillin, flu vaccine, insulin, creating safer sun screen
Chemical Engineers are in Demand
• Top 10 College Degrees by Starting Salary– #2 behind petroleum engineering
• With growing demand for – Oil– Green energy– Medical devices and medicine– Pollution treatment
• Along with a growing # of retiring baby boomers
Many new developing positions for Chemical Engineering
Chemical Engineering: The gateway engineering
• Opportunities for:– Management, Marketing, Business
Examples• Linus Pauling – Nobel Prize in Chemistry, 1954, Nobel Peace Prize,
1962• Jack Welch – Former CEO of GE• Lee Raymond – ExxonMobile chairman and CEO• Victor Mills – Invented first disposable diaper• Robert Gore – Inventor of Gore-Tex• Samuel Bodeman – Former United States Secretary of Energy
(2005-2009)
A Chemical Engineer’s Curriculum
• Lots of Math, Chemistry and Physics• Fundamental Classes– Heat and Mass Transfer– Chemical Thermodynamics– Chemical Kinetics– Fluid Mechanics– Unit Operations: chemical reactors, bioreactors,
distillation columns, heat exchangers– Design Chemical Process – integrate process units with
regard to economics, safety and environmental impact
Job Opportunities
And many more…
Chemical Engineering:The Fundamentals
Time is Money
• Chemical Engineers are usually trying to make a process faster, cheaper, sustainable and more economical– Examples• Mixing Soap with sound instead of mixing blades• Less hazardous waste
– Green plastics (biodegradable)– Less toxic by products from Battery manufacturing
Tricks of the Trade: Black Box Theory
• Device, system or object which can be viewed solely in terms of its input, output and transfer characteristics with little to no knowledge of its inner workings
• Examples:– Computer programming; software testing– Finance: market prediction– Climate change: weather prediction– Physics: Particle Physics Hadron Collider– Human mind: fMRI Biological systems…
• Black box theory has been used in many fields of science and engineering: Including Chemistry
A + B A - B
Soap Mixing
Vat
Input/Feed: Ingredients A, B
Output: Soap
Process: Mixing A + B (SEPARATED) A + B (mixed)
Process: HeatingA(75C) A(30C)
Blackbox
Looking at your Input and Output
• Input/Output: Process Streams• Mass flow rate, m, (kg/h)
• Volumetric flow rate, V, (L/min)
.
.
mmass
time.
V volume
time
.
mV. .
Measurement Gauges
What is ρ?A.DensityB.Molar massC.Atomic weight
Relate these two equations with…
Blackbox
m1, V1
Measure
. .m2, V2
Measure
. .
Soap Mixing
Vat
Input/Feed: Ingredients A, B Output: Soap
Process: Mixing A + B (SEPARATED) A + B (mixed)
Process: HeatingA(75C) A(30C)
Unit Operations
Min
Measure
.Mout
Measure
.
Min ≠ Mout
. .
Why?Trouble Shooting?1. Incorrect measurement: Broken Gauges2. Leaks3. Soap stuck to the sides of the Vat
Soap Mixing
Vat
Input/Feed: Ingredients A, B Output: Soap
The volumetric flow rate of CCl4 ( = 1.595 g/cm3) in a pipe is 100.0 cm3/min. What is the mass flow rate of the CCl4?
mV. .
min/33/ 0.100595.1 cmcmgm .
min/5.159 gm .
A. 15.95 g/min B.15.95 cm3/min C. 159.5 g/min D. 159.5 cm3/hr
Conservation of Mass
What goes in must come out!!
At steady state, accumulation in system = 0:
No reaction:
Input + Generation - Output - Consumption = Accumulation
Input - Output = 0
Input + Generation - Output - Consumption = 0
Each year 50,000 people move into a city, 75,000 people move out, 22,000 are born and 19,000 die. Write a balance on the population of the city.
City50,000 People/year
75,000 People/year
22,000 People/year
19,000 People/year
Write a mass balance equation for the city
City50,000 People/year 75,000
People/year
22,000 People/year
19,000 People/year
yearpeople /000,22000,19000,22000,75000,50
Is this a Black Box Question?A. YesB. No
Input
Generation
Consumption
Output
Input + Generation - Output - Consumption = 0
A feed stream of pure liquid water enters an evaporator at a rate of 0.5 kg/s. Three streams come from the evaporator: a vapor stream and two liquid streams. The flow-rate of the vapor stream was measured to be 4 X 106 L/min and its density was 0.004 kg/m3. The vapor stream enters a turbine, where it loses enough energy to condense fully and leave as a single stream. One of the liquid streams is discharged as waste, the other is fed into a heat exchanger, where it is cooled. This stream leaves the heat exchanger at a rate of 0.1893 kg/s. Calculate the flow rate of the discharge and the efficiency of the evaporator.
Question 3: Mass Balance
One thousand kilograms per hour of a mixture of benzene (B) and toluene (T) containing 50% benzene by mass is separated by distillation into two fractions. The mass flow rate of benzene in the top stream is 450 kg B/h and that of toluene in the bottom stream is 475 kg T/h. The operation is at steady state. Write balances on benzene and toluene to calculate the unknown component flow rates in the output streams.
Question 4
Question 5
Two methanol-water mixtures are contained in separate flasks. The first mixture contains 40.0 wt% methanol, and the second contains 70.0 wt% methanol. If 200 g of the first mixture is combined with 150 g of the second, what are the mass (m) and composition of the product?
m (g)
x (g CH3OH/g)1-x (g H2O/g)150g
200g
Case Study: High Fructose Corn Syrup
From Corn to your… Everything
High Fructose Corn Syrup
• Milestones– 1957 – Process
developed by Richard O. Marshall and Earl R. Kooi
– Up until 1970: sucrose used as a main sweetener
– 1975 – 1985 – HFCS introduced to processed foods and soft drinks
– Common forms: HFCS 42 and HFCS 55
High Fructose Corn Syrup in our Food
• Beverages: Soft Drinks, Juice, Gatorade, Milk, Vitamin Water
• Baked goods: Bread, Pastries, Crackers, Granola bars• Breakfast Cereal• Fruit: Canned, Fruit cups• Condiments: Salad Dressing, Ketchup, Peanut butter
Soft Drinks 95%Baked Goods 25%Diary 30%Processed Foods 45%
High Fructose Corn Syrup and Our Health• Health Concerns
– Links to• Obesity• Cardiovascular disease• Diabetes
– Studies show weight gain in rats who consume HFCS is higher than in rats consuming the same amount of calories of natural sugar
Sold in a bushel: 56 pounds of wet corn(48.1 lb of dry corn + 7.9 lb of water)
Milling Process
Corn Oil 1.6 lb
Cornmeal 2.5 lb
Animal Feed 12.5 lb
Starch 31.5 lb
Water 7.9 lb
Processing Corn
Extract Weight/Bushel Cost/Pound Cost/BushelCorn Oil 1.6 lb $0.27/lb $0.43/bushel
Cornmeal 2.5 lb $0.132/lb $0.33/bushel
Animal Feed 12.5 lb $0.044/lb $0.55/bushel
Starch 31.5 lb ? ?
Water 7.9 lb --- ----
$1.31/bushel
Raw Material Weight/Bushel Cost/Pound Cost/BushelWet Corn 56 lb $0.047/lb
Cost Analysis of Harvesting Corn
What is the Cost to produce one bushel of Wet Corn: Units Conversion
56 lbs $0.0471 lbs
X =$2.631 Bushel1 Bushel
X
$2.63/bushel
A. $0.26 B.$2.63 C. $2.36D. $3.84
Corn Starch High Fructose Corn Syrup
• Liquefication (Mash)– G-G-G-G-G-G G, G-
G, G-G-G• Saccharification– G-G, G-G-G G, G,
G, G, G• Isomerization– Glucose
Fructose
α-amylase
Glucoamylase
Glucose isomerase
Corn Starch
Other ExtractsStarch Purification
Liquefaction
Saccharification
Isomerization
Separator
55% HFCS42% HFCS
α-amylaseplant
glucoamylaseplant
glucoisomeraseplant
3 hrs, pH 6-7, Initial: 300F, 30 min, Heat: 185F, 30 min, Cool: 140F, 30 min
40-90 hours, pH 4, 140F
30 min process, pH 7, 140-150F
Composition % Fructose % Glucose % Solid
HFCS 42 42 58 70
HFCS 55 55 45 70
Raw Material Weight/Bushel Cost/lb Cost/Bushel
HFCS 42 31.5 lb $0.18/lb $5.67
HFCS 55 31.5 lb $0.20/ lb $6.30
Extract Weight/Bushel Cost/Pound Cost/Bushel
Corn Oil 1.6 lb $0.27/lb $0.43/bushel
Cornmeal 2.5 lb $0.132/lb $0.33/bushel
Animal Feed 12.5 lb $0.044/lb $0.55/bushel
Starch 31.5 lb $0.18/lb $5.67/bushel
Water 7.9 lb --- ----
$7.42/bushel
Raw Material Weight/Bushel Cost/Pound Cost/Bushel
Wet Corn 56 lb $0.047/lb $2.63/bushel
Cost Analysis of Harvesting Corn