Title: United Arab Emirates University College Of Engineering Chemical Engineering Department Graduation Pr
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2United Arab Emirates UniversityCollege Of
EngineeringChemical Engineering
DepartmentGraduation Project I
The Design of Formaldehyde Production Plant
Group Members
Abrar Abdalla Ahmed 200002089 Ayisha
AL-Marzouqi 200002243 Huda Tag Hamza
200004386 Noora Al-Mulla 200002122 Supervisors
Advisor Dr. Mohammed Nounou
3Objectives
- First formaldehyde plant in UAE.
- Economical, Environmental safety.
4Presentation layout
1- Formaldehyde background.
2- Process selection.
3- The description of the silver catalyst
process .
5- Material and energy balances calculations.
6- Safety and environmental impact.
7- Preliminary cost estimation.
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6Formaldehyde background
1- Definition.
2- History .
3- Physical and chemical characteristics.
4- Availability and market.
5- Uses and applications.
7Definition
Simplest form of aldehyde
Chemical formula
HCHO
8History
Butlreov
USA
1859
1901
9 Availability and market
Japan
Canada
America
10Availability and market Gulf region
Saudi Arabia
11Uses and applications
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13Formaldehyde Production Process
1- Oxidation of dimethyl ether
2- Partial oxidation of methane
3- Dehydrogenation and/or Oxidation of methanol
14Dehydrogenation and/or oxidation of methanol
Methanol processes
Silver catalyst 75
Metal Oxide catalyst 25
15Process selection
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1788oC
35oC
Tail gas
water
Water
145 oC
Converter
Distillation Column
Cooling Water
Absorber
Air washer
88oC
145 oC
Air
110 oC
160oC
Methanol superheater
64.7oC
35oC
Methanol vaporizer
37 CH2O1 CH3OH
Fresh methanol
Recycled methanol
18Water steam
145 oC
145 oC
Air fed
Methanol superheater
160 oC
64.7oC
Methanol vaporizer
Fresh methanol
Recycled methanol
19Tail gas
Water
Recycled methanol
Reactor effluent
Product
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21(Material balance)Objective
- Amount of raw materials
- Compositions flow rates
22Degree of freedom
Ndf Nunknowns Nindependent equations
Nunknowns 12
Msteam MH2O MTail gas Mmethanol Mair
Compositions in tail gas HCHO, CO2, CO, H2,
H2O, C2H4O2, N2
MH2O
MTail gas
Msteam
Mair
Nindependent equations 4
Mmethanol
Mproduct
atomic balance equations (H, N, C, O).
23Degree of freedom
Ndf 12 4 8
Ndf 12 12 0
20 Tail gas H2 0.1Tail gas C2H4O2
EPA - HCHO - CO2 - CO
Yield 0.92
Ratio of air to methanol
30 of the feed entering the reactor is steam
24Assumptions and specifications
30 of the reactor feed is steam
Plant yield 92
25Distillation Column
Top product
Basis Product 5,707,762 kg/hr
From absorber
Bottom product
26 Fresh methanol 2,448,547 Kg/hr
88oC
35oC
Tail gas
Yield 92
water
Water
145 oC
Converter
Distillation Column
Cooling Water
Absorber
Air washer
88oC
145 oC
Air
110 oC
160oC
Methanol superheater
64.7oC
35oC
Methanol vaporizer
37 CH2O1 CH3OH
Fresh methanol
Recycled methanol
27 Recycled stream /Fresh methanol 1 / 3
Recycled stream 812,611 Kg/hr
88oC
35oC
Tail gas
water
Water
145 oC
Converter
Distillation Column
Cooling Water
Absorber
Air washer
88oC
145 oC
Air
110 oC
160oC
Methanol superheater
64.7oC
35oC
Fresh methanol
Methanol vaporizer
37 CH2O1 CH3OH
Recycled methanol
28Air / Methanol 0.9/1
Air fed 2,656,138 Kg/hr
Water
145 oC
Cooling Water
Air washer
145 oC
Air
160oC
Methanol superheater
64.7oC
Fresh methanol
Methanol vaporizer
Recycled methanol
2930 of reactor feed is steam
Water steam 2,529,704 kg/hr
Reactor feed 8,432,346 kg/hr
Mixing point
Mass in Mass out
Water steam
145 oC
Cooling Water
Air washer
145 oC
Air
160oC
Methanol superheater
64.7oC
Fresh methanol
Methanol vaporizer
Reactor effluent 8,432,346 kg/hr
Recycled methanol
30Distillation Column
Recycled stream Top Product 812,611 kg/hr
Feed 6,520,374 kg/hr
88oC
Product 5,707,762 kg/hr
35oC
37 CH2O1 CH3OH
31Tail gas 100,409 kmol/hr
Tail gas
water
Overall carbon atomic balance
Water steam
145 oC
Converter
Distillation Column
Cooling Water
Absorber
88oC
145 oC
Air
110 oC
160oC
Methanol superheater
64.7oC
Product
Methanol vaporizer
Fresh methanol
Recycled methanol
32N2 0.72
Neglect (H2O) in tail gas MWav. 22.8 Kg/Kmol
Tail gas
water
Tail gas 2,249,102 kg/hr
Water steam
145 oC
Converter
Distillation Column
Cooling Water
Absorber
88oC
145 oC
Overall Nitrogen balance
Air
110 oC
160oC
Methanol superheater
64.7oC
Product
Methanol vaporizer
Fresh methanol
Recycled methanol
33 XN20.75
XH2O0.009
Water 337,129 kg/hr
Tail gas
water
Water steam
145 oC
Converter
Distillation Column
Cooling Water
Absorber
88oC
Overall mass balance
Overall hydrogen atomic balance
145 oC
Air
110 oC
160oC
Methanol superheater
64.7oC
Product
Methanol vaporizer
Fresh methanol
Recycled methanol
34(Energy balance)Objectives
- Amount of energy power requirements
35Energy balanceDistillation Column
TD 64.85oC
HD
HD 0 kJ/hr
Hf
Tw 91.5 oC
Hw Hf - HD Hw Hf 5.7108 kJ/hr
Hw mw Cpw (Tw-Tref)
Hw
36Reboiler condenser duties
Condenser duty Qc Hv 2.7109 kJ/hr mH2O
3.2107 kg/hr
HD
Reboiler duty Qrb Qc Hw HD - Hf Qrb
2.7109 kJ/hr mH2O 1.2106 kg/hr
Hf
Hw
37Cooler
1- Amount of cooling water mw Cpw (Tw 35)
mH2O CpH2O (Tout Tin)
HD
mH2O 6.77106 kg/hr
Hf
Hw
35oC
91.5oC
38Energy balanceAbsorber
88 oC
35 oC
Qrb H15- HH2O - Hf
Water
, TH2O 20 oC
Qrb 6.56108 kJ/hr
Hf
Qc HH2O Qrb Hf H15 Hw
TR 110 oC
Qc 1.61108 kJ/hr
Hw
39Methanol vaporizer superheaterduties
Q1QR mm Cpm (Tm-Tref) Tm 56 oC
QA
QA msteam?H2O mair ?Cpair?T QA 5107
kJ/hr msteam2.21104
Qv mm? mm cpm ?T 3.64109 kJ/hr msteam
1.61E06 kg/hr
Qs
Qv
Q1
Qs msteam?H2O mm ?Cpm?T 5107 kJ/hr msteam
1.67E06 kg/hr
T 1 30oC
T m
, QR
T R 64.85oC
40Energy balanceReactor
145 oC
?HR -2.1108 kJ/hr
mH2O 9.26107 kg/hr
Cooling water
Qc 1.6109 kJ/hr
Qc
110 oC
160 oC
mH2O 1.9107 kJ/hr
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42Where does formaldehyde exist?
43Sources of exposure
Tobacco smoke
Oil refineries
Engine exhaust
44Limits of exposure
- Acute duration (0.04 ppm)
- Intermediate duration (0.03 ppm)
- Chronic duration (0.008 ppm)
45Environmental Impact
Formaldehyde in nature
Air
Soil
Water
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47Plant Capital Cost
Capital cost definition
Step counting method
Timms Correlation
C' 13000 N Q0.615
N 3 Q 50,000,000 tonne/ year
C' 2.12E09
Cost in year 2004 2.5E09
48Conclusion
- Tasks achieved
- Plan for next semester
49References
- 1- Robert H. Perry, Don W. Green, Perry Chemical
Engineers Handbook, seventh edition, McGRAW
international, 2003. - 2- K.Weissermel, H.-J.Arpe, Industrial Organic
Chemistry, Third compeletely revised edition, VCH
A wiley company, 1997. - 3- R. Norrris shereve, Chemical process
industries, fourth edition, McGRAW Hill book
company,1977. - 4- Kirk-othmer, Encyclopedia of chemical
technology, fourth edition, volume 11, A wiley
interscience publication, New York, 1992. - 5- Sybil P. Parker, Encyclopedia of chemistry,
second edition, McGRAW Hill book company, 1993,
pages 408-410, 637-638. - 6- Douglas M. Considine, Chemical and process
technology encyclopedia, McGRAW Hill book
company, 1974.
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