Chemical ManufacturingChemical Manufacturing
By: Robert McVicar & Brenna Lindsey-SweckerBy: Robert McVicar & Brenna Lindsey-Swecker
Main customers of chemical manufacturers are:• Auto industry• Agricultural industry• Housing industry, and • Product manufacturing industry
2The Chemical Industry is a principle contributor to the US economy
2Environment: Industry emits more than 1.5 million tons of categorized air pollutants
CHEMICAL MANUFACTURING: 1Raw materials from environment to industry and consumer useful products*Commodity = Large quantities, single chemical*Specialty = Small scale, “made to order”
Sulfuric Acid Sulfuric Acid 33The Most Important ChemicalThe Most Important Chemical
• Has been manufactured for more than 400 years• 150 million tons of sulfuric acid is produced
annually• A nation’s level of sulfur production can be used
to indicate the nation’s industrial compactly. • Surprisingly inexpensive ($150/ton)
– Each step is an exothermic process– Heat is sold as energy
• Average daily production of sulfuric acid produces 7x106 watts of electric power.
Uses of Sulfuric AcidAmazing number of applications…
Sulfuric Acid Production Process1. Obtaining sulfur: modern contact
process is used.
• Claus process utilized: H2S in natural gas is chemically separated then oxidized:
• 2H2S(g)+2O2(g) 1/2S8(g)+SO2+2H2O(g)
• 2H2S(g)+SO2(g) 3/8S8(g)+2H2O(g)
Sulfuric Acid Production ProcessSulfuric Acid Production Process• When natural gas is not readily available but there
are natural underground deposits the Frasch process is utilized:
• A hole is drilled, superheated water melts the sulfur.• A combination of hydrostatic pressure and the
pressure of condensed air force the sulfur to the surface.
• Produces a very pure substance.
Sulfuric Acid Production ProcessSulfuric Acid Production Process2. From sulfur to sulfur dioxide.
• Sulfur is burned in air to obtain SO2
• 1/8S8(s) + O2(g) SO2(g)
• ΔH° = -297 kJ
Sulfuric Acid Production ProcessSulfuric Acid Production Process3. From sulfur dioxide to trioxide: the
contact process oxidizes SO2 with O2 to form SO3
• SO2(g) + 1/2O2 SO3(g)
ΔH° = -99 kJ
• Reaction is exothermic and occurs very slowly at room temperature.
Sulfuric Acid Production ProcessSulfuric Acid Production Process• Le Chatelier’s principle plays major role in third step.
Yield of SO3 Affected by…
Temperature
T Rate
TYield of SO3
Exothermic reaction therefore
shift to products
Catalyst used to maximize Rate & Yield
Pressure *small effect
ConcentrationDouble O2, Shift to Products. Remove SO3 as produced to encourage more production.
Sulfuric Acid Production ProcessSulfuric Acid Production Process
4. From sulfur trioxide to acid
• First a hydration step:
SO3(g) + H2O(l) H2SO4(l)
SO3(g) + H2SO4(l) H2S2O7(l)
H2S2O7(l) + H2O(l) 2H2SO4(l)
http://www.ism.ws/pubs/EmailNewsletters/ChemicalsNewsletter/eDigestChemicalDetail.cfm?ItemNumber=4640
ChlorineChlorineRanked in top ten chemicals produced in the United StatesRanked in top ten chemicals produced in the United States
4Used in over 50 percent of all industrial chemical processes: • 90 percent of pharmaceuticals• 96 percent of crop protection chemicals.
http://www4.uwm.edu/shwec/publications/newsletters/pills.jpg
ChlorineChlorineThe chlor-alkali process electrolyzes NaCl(aq) to produce Cl2 (and other important chemicals)
• Asbestos Diaphragm• Mercury-Cell • Membrane-Cell
http://www.bayertechnology.com/uploads/pics/chlorine_electrolysis_references_01.jpg
Electrolysis Plant
Chlor-alkali Process
Anode: Cl- oxidixedCathode: H20 reduced
Half-Reaction2Cl-(aq) Cl2(g) + 2e- Eo = 1.36v
2 H20 + 2e- 2OH-(aq) + H2(g) Eo = -1.0vTotal Ionic2Na+(aq) + 2Cl-(aq) + 2 H20 2Na+(aq) + 2OH-(aq) + H2(g) + Cl2(g)
Cathode compartment is a mix of NaCl and NaOH - NaCl removed by fractional crystallization
Electolysis of NaCl salt yields Cl2, H2 and NaOH
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Chlor-alkali ProcessAsbestos Diaphragm
Diaphragm separates half cell compartments
* Cl2 and H2 kept apart to prevent explosive combination
Chlor-alkali Process
Mercury-Cell
Mercury replaced at cathode(favors Na+ reduction) 2Cl-(aq) Cl2(g) + 2e-
2Na+(aq) + 2e- +Hg 2Na(Hg)
Sodium Amalgam treated with water2Na(Hg) + 2 H20 -Hg 2Na+(aq) + 2OH-(aq) + H2(g)
Being phased out due to water contamination - 200 g Hg per ton of Cl2 produced!
http://www.geneticmaize.com/2009/02/whats-in-the-corn-syrup-guest-post-by-renee-dufault/
Chlor-alkali Process
Membrane-CellReplaces Diaphragm with polymeric membrane - Allows cations to move through
Cl- removed at anode to form Cl2
Na+ ions travel through membrane
to cathode
Na+ ions form NaOH
*Uses less electricity and purity of NaOH
greater
Information ReferencesInformation References
1http://www.libraries.psu.edu/psul/business/industry_guides/chemical.htm
2http://www.epa.gov/ispd/chemical/index.html3Chemistry Textbook4http://worldchlorine.com/products/index.html