Notes on Chemical Engineering Calculations 1 with input

 There’s no need to memorize cubed or
Notes on CheCal 1 with input squared conversion factors
1 𝑔∙𝑐𝑚/𝑠2
Collab on 08/12/21  gc = 𝑑𝑦𝑛𝑒
32.174 𝑙𝑏𝑚 ∙𝑓𝑡/𝑠2
=
𝑙𝑏𝑓
1 𝑘𝑔∙𝑚/𝑠2
 Difference of Units and Dimensions: = 𝑁
o Units: standard way of
Not on collab notes:
describing physical quantity
o Dimensions: physical quantity
 Conversion Factor: gives the relationship  1 Btu = 3.93 x 10-4 hp-hr
of the two units involved; in fraction
form
 SI Units: Collab on 08/17/20
o Greek prefixes
o In powers of 10
o Base unit + Greek prefix (also  Density as conversion factor
called multiplier) o 1 g/cm3 = 62.4 lb/ft3
 Format for solution: o 1 cP = 0.01 g/cm•s
o Given, required, solution:  For dimensional analysis/consistency;
conversion factors then solution changing the units of the components:
 For answers: o Do it reverse, use the goal units
o Usually 5% difference or then convert back to the original
deviation from calculated unit –new units back to original
answer for engineering students units
but only 0.1% for sir o Work only on one side of the
 “No particular rule for rounding off”, as equation
long as it is reasonable and not too long o The resulting unit of the
**use exponential form if possible to be equation is added at the end and
safe will be converted to the
 Exponential and logarithmic shouldn’t desired/goal unit
have units  Try checking the method in SIM, the one
 gc is a conversion factor to relate mass that tackles temperature etc.
and force
**it’s referred to as the “C” in
Himmelblau’s where it is defined as a Collab on 08/19/21
constant with a value of one to balance
the units and is dependent on the units
of the dimensions used in the equation  Mole unit
 Dyne: is force used for small objects o Amount of particles (molecules,
 In writing exponential form: x 10n as en atoms, electrons)
o 0.012 kg of C-12

, 
1000𝑔
 𝑚𝑐 = 0.012 𝑘𝑔 × = 12 𝑔 Usual density used as reference for
1 𝑘𝑔
𝑚 12 𝑔
 𝑛= = = 1𝑚𝑜𝑙𝐶 solids and liquids is density of water at
𝐹𝑊 12 𝑔/𝑚𝑜𝑙

o Etymology > mole > Latin > heap 4˚C >> 1.00 g/cm3
o 20°
Amount of substance  𝑆𝐺 = 0.72 4°
o 1 mole = 6.022x1023 o Numerator: temperature of
atoms/molecules/ions substance when measured
 Avogadro’s number of o Denominator: temperature of
elementary reference when measured
units/entities
 ˚API
𝑚 𝑖𝑛 𝑙𝑏
o 1 𝑙𝑏𝑚𝑜𝑙 =𝑀𝑊 𝑖𝑛 𝑙𝑏/𝑙𝑏𝑚𝑜𝑙 o American Petroleum Institute
𝑚 𝑖𝑛 𝑔 141.5
o 1 𝑔𝑚𝑜𝑙 = 𝑀𝑊 𝑖𝑛 𝑔/𝑔𝑚𝑜𝑙 o °𝐴𝑃𝐼 = 60℉ − 131.5
𝑆𝐺
60℉
𝑚 𝑖𝑛 𝑘𝑔
o 1 𝑘𝑔𝑚𝑜𝑙 = 𝑀𝑊 𝑖𝑛 𝑘𝑔/𝑘𝑚𝑜𝑙 o Hydrometric scale based on
 Also kgmol petroleum products
o Measure of the density of
 Density
petroleum liquid in relation to
o Mass of substance per unit
density of water
volume
o Gravity or density of crude oil
o Kg/m3, lb/ft3, g/mL, g/cm3
and liquid petroleum products
 Specific volume is reciprocal of density
o Devised by American Petroleum
 Density of water, at 80-100
Institute and NIST – National
temperature, density changes (it goes
Institute of Standards and
down)
Technology
 Relative density = specific gravity
o Oil with the least specific gravity
 SG
has the highest API gravity
o A universal reference scale
o API gravity is directly
o Has two major drawbacks:
proportional with temperature
 Laboratory precision
(SG is inversely proportional to
 Limited range of scale
T)
o Often expressed to an accuracy
 Volume of petroleum
of 2 or 3 decimal places
liquid is directly
 Reference density for SG:
proportional to
o For liquids and solids, water
temperature
o For gases, air
o Crude oil quality standard
 Comparing the density-temperature
adopted worldwide
graph of NH3 and water, the former has
o Indicate oil quality
apparent changes in density depending
o One of the important factors in
on the temperature
deciding the price of various
 Solutions assume no changes in density varieties of crude oil
as temperature changes o ˚API > 45, extra light crude oil
𝜌𝑠𝑢𝑏𝑠𝑡𝑎𝑛𝑐𝑒
 𝑆𝐺 = o ˚API (33,45), light crude oil
𝜌𝑟𝑒𝑓𝑒𝑟𝑒𝑛𝑐𝑒

, o ˚API (22, 33), medium crude oil 𝑆𝐺−1
o °𝑇𝑊 = 0.0005
o ˚API (10, 22), heavy crude oil o Scale for SG of solutions, first
o ˚API ≤ 10, extra heavy crude oil two digits to the right of the
o Light crude oil is more expensive decimal point multiplied by 2
than heavy crude oil o Reports the measured SG of a
 Higher percentage of liquid relative to water
gasoline and diesel fuel o Only used for liquids with SG
 Baumé scale greater than that of water
o ˚Be  Usually ranges between
145
o °𝐵𝑒 = 145 − 𝑆𝐺 1.00 and 1.85
 Heavier than water o Used in the British dye and
145 bleach manufacturing industries
o °𝐵𝑒 = 𝑆𝐺
− 130
o W. Twaddell Glasgow/ Thomas
 Lighter than water
Twaddell > coined after
 Some sources say it’s
o Charles Macintosh > person
140/SG
behind
o Antoine Baumé
o Used philosophical bubbles or
o Devised for making
SG beads
hydrometers
o Used in heavy industries to
o Used to determine the sugar
determine strength of solution
content of must
of various substances such as
o Used to calculate what the
brine, sugar solutions (syrup,
wine’s alcohol content will be
juice, honey, brewers, must) and
after fermentation
acids
o Used as a measure of density or
o Scale little known outside of UK,
concentration
mainly in England and Scotland
o SG of a sugar solution has a good
o Used for acids in tanning
correlation to sugar
industry and alkaline lye in
concentration
papermaking
 In brewing >> wine
o Uses:
making and sugar beet
 Tanning industry
processing
o A traditional description of a  Determine
solutions concentration strength of
o A number of acids has its synthetic
concentration measured in tanning agents
˚Baume >> also called heaviness  Easier to
scale determine the
o Strength of acids is expressed by extra water
their relative weight needed to
 Twaddell scale dilute mixture
to desired
o ˚TW