Chemical Engineering

Summer@Brown2012

Announcements

• Ethics of Synthetic Biology Paragraph Due Today– Please email to vince_siu@brown.edu 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