Unit 2 Chemical Technology 1.pdf coal and chicial

Syllabus
• Petrochemicals: Manufacturing processes of formaldehyde,
acetaldehyde, acetic acid, acetic anhydride, maleic anhydride,
nitrobenzene, ethylene oxide, ethylene glycol.
• Pesticides: Processes for manufacturing of insecticides, fungicides and
herbicides.
• Fuel and Industrial Gases: Technology options of producing producer
gas, syn gas, pyrogas, nitrogen, oxygen and carbon dioxide
1

Petrochemicals: Overview
Part of Chemical Technology-Unit II

Petrochemicals: An Introduction
• Chemicals which are derived directly/indirectly from petroleum or
natural gas or from hydrocarbons.
• Important group of petrochemical products: Plastics, Polymers,
Synthetic Rubber, Synthetic Fiber, Detergents, Fertilisers etc.
• Not more than 5% of the total oil and gas consumed each year is
required to produce all the photochemical products. (2014)
3

Petrochemicals and Daily Life
4

Classification of Petrochemicals
5
Petrochemicals
Olefins
(Alkenes)
Aromatics Synthesis gas
• Mainly Ethylene, Propylene
and Butadiene.
• Mainly Benzene, Toluene
and Xylene isomers
• A mixture of Carbon
Monoxide and Hydrogen

Olefin Petrochemicals
• Includes Ethene, Propene, Butene and Butadiene.
• Produced by fluid catalytic cracking of petroleum products in Oil
refineries.
• Whereas in chemical plants steam cracking of natural gas liquids
produce olefins.
• Basis for polymers, oligomers to be used in plastics, resins, fibers,
elastomers, lubricants and gels.
• Butadiene is used in synthetic rubber production.
6

Aromatic Petrochemicals
• Includes Benzene, Toluene and Xylene (Di-methyl Benzenes) isomers
(BTX)
• Produced by fluid catalytic cracking of petroleum products in Oil
refineries.
• Also produced by catalytic reforming of naphtha.
• Benzene used as a raw material for dyes, synthetic detergents. (textile,
hygiene)
• Toluene used in production of Polyurethanes. (Dish wash scubber)
• Xylenes used in making of plastics and synthetics fibers.
7

Synthesis Gas
• A mixture of Carbon Monoxide and Hydrogen.
• Mainly used as bottled fuel or raw materials for other organic
materials
• Utilised to produce Ammonia and Methanol.
• Ammonia used as a raw material for Urea. (Helping Agriculture)
• Methanol used as solvent and chemical intermediate. (Hygiene,
Industrial application)
8

Petrochemical Industry
• Part of Chemical Industry but different from petroleum industry.
• Utilize petroleum refinery products as raw material.
• Serving as an energy source for domestic, industrial, transport sectors.
• Provide feedstock for fertilizers, synthetic fibers, synthetic rubbers,
polymers, intermediates, explosives, agrochemicals, dyes, and paint
industries etc.
• A highly technological and capital intensive industry.
9

Evolution of Petrochemical Industry
• Prior to 1919, organic chemicals manufactured from coal, wood and
agricultural raw material.
• With progressive civilization demands were growing but raw materials
were stagnant.
• Problem lead to birth of synthesis of organic material using alternative
raw material source.
• Industries using petroleum products using as a raw material for
synthetic organic material production were born.
10

Growth of Petrochemical Industry
• 1918 Petro-alcohol process for making isopropyl alcohol from
Propylene obtained from petroleum refining.
• 1926 Methanol (CH3OH), Acetaldehyde (CH3CHO) and
Formaldehyde (HCHO) synthesized from petroleum sources.
• During world war II, demands of explosives, synthetics rubber and
other chemicals led to the development of synthetic Ammonia (NH3).
• Synthetic Ammonia production leaded the higher production of Nitric
Acid , Nitroglycerin explosive and Tri-Nitro Toluene (TNT).
• Petrochemical plants which were only 10 nos. in 1930 reached to 372
nos. in 1957 post world war II.
11

Growth of Petrochemical Industry
• Before 2014, Global chemical industry was reported to be valued at
$360 billion, which was 6% of global GDP. Petrochemicals was
valued 40% of that global chemical industry valuation.
• India’s petrochemical industry was valued $9 billion in that survey.
• India consumption of petrochemicals was estimated to 12-14% of
global production per year.
12

Indian Petrochemical Industry: Early days
13
Year Name Place Capacity Compound
1963 Union Carbide Mumbai 20,000 TPA Ethylene
1968 National
Organic
Chemical
Industries
(NOCIL)
Thane 60,000 TPA Ethylene
1968 Chemical and
Fibers India
Ltd. (CAFI)
Thane N/A Polyster staple
fibre (PSF)
1970 Indian
Petrochemical
Corp. Ltd.
(IPCL)
Vadodara 1,30,000 MT Petrochemical
Complex

Indian Petrochemical Industry
14

Structural hierarchy of Petrochemical
Compounds
15
Second generation
intermediates
First generation
intermediates
Target Products
• Hydrogen, Ammonia, Methanol,
Ethylene, Propylene, Benzene,
Toluene, Xylenes
• Unit processes: Dealkylation,
hydrogenation etc.
• Unit Operation: Distillation,
crystallization, adsorption
solvent extraction, membrane
separation etc.
• Introduction of various hetro
atoms in the last intermediates
like Oxygen, Nitrogen, Chlorine,
Sulfur.
• Unit processes: oxidation,
Hydrogenation, Chlorination,
Nitration etc.
adsorption solvent extraction,
membrane separation etc.
• Examples: Styrene, Dimethyl
terephthalate, Ethylene glycol etc.
• Plastics, Synthetic fibre,
Fertilizers, Solvents,
Elastomer, Drugs, Dye,
Detergent, Pesticides etc.
• Unit processes: oxidation,
Hydrogenation, Chlorination,
Nitration etc.
adsorption solvent extraction,
membrane separation etc.

Petrochemicals and end products
16

Petrochemicals feed stock
• Feedstock were the major concern which led the development of petrochemical
industries and replaced the natural feedstock like coal, fats etc. with the petroleum
fractions.
17

Petrochemicals feed stock
18
Natural gas and Petroleum fractions as petrochemicals feedstock

Alternative Petrochemicals feed stock
19
Alternative feedstock Source path
Synthesis gas Methane, coal and biomass
Methanol Conversion of synthesis gas
Olefin Methanol to Olefin
Ethanol Direct fermentation of sugar rich biomass, hydrolysis of lingo-
cellulosic biomass
Liquid fuel Reduction of CO2 using engineered bacteria, photocatalysis etc.
Naphtha Methane from natural gas liquefaction process
Coal via direct liquefaction or indirect liquefaction
FT naphtha from Biomass
Liquefaction, pyrolysis and separation processes of plastic waste

Petrochemicals feed stock in early days
20

Integration of refinery with petrochemical
• With addition of few petrochemical processes within refinery, both
petroleum and petrochemical industries can be integrated at a single
working site.
• Some of the processes listed below:
• Fluid catalytic cracking (FCC)
• Steam cracking
• Catalytic cracking
• Catalytic reforming
• Gasification
21

Summary
22
(Petrochemical lecture end)

Petrochemical Products
Compound properties, Application, Manufacturing processes, Indian
Scenario

Quoted Compounds
(as per Syllabus)
24
Compounds Book reference page number
(Dryden’s outlines of Chemical
technology)
Formaldehyde 420
Acetaldehyde 457
Acetic Acid 461
Acetic Anhydride
Maleic Anhydride 530
Nitrobenzene 536
Ethylene Oxide 449
Ethylene Glycol

Symbols used in Flow sheets
25
Type of Reactors and respective common representation

26
Columns and respective common representation Heat transfer equipment and respective common
representation

27
Miscellaneous

Formaldehyde (HCHO)
28
IUPAC Name Methanal
Common names Methyl Aldehyde
Formalin
Carbonyl Hydridde
Oxomethane
CAS Number 50-00-0
(Chemical Abstract Service
Registry Number)
Grades CP Gas (Commercial Pure)
37% aqueous
Trioxane Polymer (CH2O)3
(Solid form)
Paraformaldehyde,
(CH2O)n*nH2O (n=10-50) (Solid
form)
Chemical properties Property Value
Molecular Weight 30.026
Melting Point - 1180 C (decomposes at 1640 C into
CO2 and H2O)
Boiling Point -190 C
Density 0.1853 gm.cm-3 (-200 C)
Color Colorless (Gasseous, Liquid phase)
White solid crystalline
Odor Pungent, suffocating smell
Flash point 640 C
Explosive Limits 7-73 vol% in air
Solubility Water, alcohol and polar solvents
Slightly soluble in hydrocarbons,
chloroform,ether
Toxicty limit 10 ppm

29
Commercial applications of Formaldehyde
Production of Formaldehyde: Indian Scenario (till 2004)
• 17 formaldehyde production units.
• 1.89-2.72 lakhs tonnes per annum

Production of Formaldehyde: Methods
• Catalytic Oxidation – Dehydrogenation of Methanol (Methanol may
be obtained from Synthesis gas or food stock fermentation)
Chemical reactions
1. Catalytic Oxidation
𝐶𝐻3𝑂𝐻 +
1
2
𝑂2 → 𝐻𝐶𝐻𝑂 + 𝐻2𝑂; ∆𝐻 = −37 𝑘𝐶𝑎𝑙
2. Dehydrogenation of Methanol (Pyrolysis)
𝐶𝐻3𝑂𝐻 → 𝐻𝐶𝐻𝑂 + 𝐻2; ∆𝐻 = +19.8 𝑘𝐶𝑎𝑙
3. Complete combustion (Side reaction)
𝐶𝐻3𝑂𝐻 +
3
2
𝑂2 → 2𝐻2𝑂 + 𝐶𝑂2; ∆𝐻 = −162 𝑘𝐶𝑎𝑙
• Separation from oxygenated hydrocarbons co-products produced
from Oxidation of Methane or LPG
30

Production of Formaldehyde: Flow sheet
31
To be pre-heated and feed
quantity maintained 30-50% of
methanol feed
Mixing of
raw
materials
Catalyst: Ag or Cu or
their oxides
450-
6000 C

Production of Formaldehyde: Process
Description
32
Indian industries producing Formaldehyde
1. Aegis Chemical Industries Ltd., Vapi (Gujrat)
2. Assam Petrochemicals Ltd., Dibrugarh (Assam)
3. Hindustan Organic Chemicals Ltd., Raigad
(Maharashtra)
4. Pentasia Chemicals Ltd., Kudikadu (Tamilnadu)
5. Bakelite Hylam Ltd., Hyderabad (Telangana)

Acetaldehyde (CH3CHO)
33
IUPAC Name Ethanal
Common names Ethyl Aldehyde
Acetic Aldehyde
Acetylaldehyde
CAS Number 75-07-0
Registry Number)
Grades CP (Commercial Pure)
50% aqueous
Melting Point - 123.370 C (decomposes at 1640 C
into CO2 and H2O)
Boiling Point 20.20 C
Density 0.784 gm.cm-3
Color Colorless (Gasseous, Liquid phase)
Odor Pungent, Fruity smell
Flash point -400 C
Solubility Water, alcohol, organic solvents and
polar solvents
Slightly soluble in chloroform
Toxicity Carcinogenic

34
Commercial applications of Acetaldehyde
Production of
Acetaldehyde: Indian
Scenario (2008-09)
• Installed capacity:
238000 MT
• Production (2009-
10): 59,200 MT

Production of Acetaldehyde: Flow sheet
35
1. Previously made only by hydration
of acetylene in the presence of
liquid HgSO4
𝐶2𝐻2 + 𝐻2𝑂 → 𝐶𝐻3𝐶𝐻𝑂
2. In early 1960’s ethylene was started
to be used as starting raw material,
as it was lower in cost and higher in
availability. Hence preferred method
𝐶2𝐻4 +
1
2
𝑂2 → 𝐶𝐻3𝐶𝐻𝑂
• Above process operates in the
presence of liquid copper salt
catalyst promoted by metal e.g.
Palladium.
• Reactor pressure < 50 atm
• 50 < Reactor Temperature < 1000 C
Compressor
Reactor
Cyclone
separator
Stripper
Catalyst
regenerator
𝑪𝟐𝑯𝟒 + 𝟐𝑪𝒖𝑪𝒍𝟐 + 𝟐𝑯𝟐𝑶 → 𝑪𝑯𝟑𝑪𝑯𝑶 + 𝟐𝑪𝒖𝑪𝒍 + 𝟐𝑯𝑪𝒍
𝟐𝑪𝒖𝑪𝒍 + 𝟐𝑯𝑪𝒍 +
𝟏
𝟐
𝑶𝟐 → 𝟐𝑪𝒖𝑪𝒍𝟐 + 𝑯𝟐𝑶
Reactor reaction
Catalyst regeneration reaction

Acetic Acid (CH3COOH)
36
IUPAC Name Ethanoic Acid
Common names Vinegar (In dilute form)
Hydrogen Acetate
Ethylic Acid
Glacial
CAS Number 64-19-7
Registry Number)
Grades CP (Commercial Pure)
50% aqueous
Melting Point 16-170 C
Boiling Point 118-1190 C
Color Colorless (Liquid phase)
Odor Vinegar smell
Flash point 400 C
Solubility Water, alcohol, organic solvents
Toxicity Hazardeous

37
Commercial applications of Acetic Acid
Various production routes
of Acetic Acid
• Methanol carboxylation
(Most used route)
• Acetaldehyde oxidation
• Ethanol
dehydrogenation/oxidation
• Butane/naphtha oxidation

Production of Acetic Acid: Global Scenario
38

Production of Acetic Acid: Indian Scenario
39

Ethylene Oxide (C2H4O)
40
IUPAC Name Epoxyethane
Common names Oxirane
Dimethylene Oxide
Epoxide
CAS Number 75-21-8
Registry Number)
Melting Point -111.70 C
Boiling Point 10.70 C
Colour Colourless
Odor Ether like
Flash point -150 C
Solubility Water, alcohol, organic solvents
Toxicity Carcinogenic, 25-100 ppm

41
Commercial applications of Ethylene Oxide

Production of Ethylene Oxide: Method
42
𝑪𝟐𝑯𝟒 +
𝟏
𝟐
𝑶𝟐 → 𝑪𝟐𝑯𝟒𝑶; ∆𝑯 = −𝟐𝟗. 𝟐 𝒌𝑪𝒂𝒍
(𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 𝑐𝑜𝑛𝑑𝑖𝑡𝑖𝑜𝑛𝑠 =
𝐴𝑔𝑂
250 − 3000 𝐶, 4 − 5 𝑎𝑡𝑚𝑠
)

Production of Ethylene Oxide: Flow sheet
43
(𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 𝑐𝑜𝑛𝑑𝑖𝑡𝑖𝑜𝑛𝑠
=
𝐴𝑔𝑂
250 − 3000 𝐶, 4 − 5 𝑎𝑡𝑚𝑠
)

Production of Ethylene Oxide: Process Description
44

Ethylene Glycol (CH2OH)2
45
IUPAC Name Ethane-1,2-diol
Common names Ethylene alcohol
Monoethylene glycol (MEG)
Glycol
1,2-Ethanediol
CAS Number 107-21-1
Registry Number)
Melting Point -12.9 0C
Boiling Point 197.3 0C
Colour Colourless
Odor Odorless
Flash point 111 0C
Explosive Limits 3.2-15.2 vol% in air
Solubility Organic solvents
Toxicity Harmful

46
Commercial stats of Ethylene Glycol: Global scenario
• List of Global production plants
Shell, Equistar SABIC, INEOS,
LyondellBasell, Reliance Industries Ltd,
Akzo Nobel, BASF, Clariant, Dow
Chemical, Huntsman, LG Chem, Mitsubishi
Chemical Corp, Mitsui Chemicals, Sasol,
Shanghai Petrochemical, Sinopec etc.
Application
1. Antifreeze in heating and cooling
systems
2. De-icer
3. Solvent for paint and plastic industries.
4. Batteries
5. Synthetic fibers, like Dacron
6. Printer ink and ink for that ballpen
7. Polymers, namely Polyethylene
Terephthalate (PET).
8. Fibre glass
Production capacity of Ethylene Glycol worldwide from 2014 to 2024
(in million metric tons)
https://www.statista.com/statistics/1067418/global-ethylene-glycol-production-
capacity///

Production of Ethylene Glycol: Method
47
Non-catalytic thermal Hydrolysis of Ethylene Oxide in presence of excess
water
Chemical reactions
1. Ethylene Glycol as principal product (CH2OH)2
𝑪𝟐𝑯𝟒𝑶 + 𝑯𝟐𝑶 → 𝑯𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑯; ∆𝑯 = −𝟐𝟐 𝒌𝑪𝒂𝒍
2. Bi-products (Side Reaction)
• Di-ethylene glycol (DEG) {(HOCH2CH2)2O}
𝑯𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑯 + 𝑪𝟐𝑯𝟒𝑶 → 𝑯𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑯; ∆𝑯 = −𝟐𝟓 𝒌𝑪𝒂𝒍
• Tri-ethylene glycol (TEG) {H(CH2CH2O)3OH}
𝑯𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑯 + 𝑪𝟐𝑯𝟒𝑶
→ 𝑯𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑪𝑯𝟐𝑪𝑯𝟐𝑶𝑯; ∆𝑯 = −𝟐𝟒 𝒌𝑪𝒂𝒍

Production of Ethylene Glycol: Flow scheme
48

Production of Ethylene Glycol: Process Description
49
1. Finished (purified) ethylene oxide (EO): water mixture is the principal feed to the process.
2. Subsequently, the pressure is boosted on this feed via a high head pump, and it is then heated to reaction
conditions.
3. The glycol reactor is of tubular construction, usually arranged in a vertical serpentine-like layout for
reasons of space and heat insulation.
4. Back mixing is avoided by establishing fully-developed turbulent flow through the reactor. Back
mixing, favors the side reactions by enabling reaction between unreacted EO and produced EG.
5. Reactor length is set to provide three minutes residence time, which allows 99.99% of the ethylene
oxide to be reacted.
6. Excess water (some water is consumed in the hydrolysis reaction) in the glycol reactor product is
removed in evaporator, with final reduction of water content achieved in vacuum column, the
dehydrator.

Production of Ethylene Glycol: Process Description
50
7. Vacuum column completes the recovery of the glycols. This column reduces the water content of the
crude glycols stream to less that 100 ppm (by weight).
8. Last three vacuum columns in turn, separate the MEG, DEG, and TEG products into the required
purities needed for sales.

Nitrobenzene (C6H5NO2)
51
IUPAC Name Nitrobenzene
Common names Nitrobenzol
Oil of mirbane
CAS Number 98-95-3
Registry Number)
Melting Point 5.7 0C
Colour Pale Yellow
Odor Pungent
Flash point 88 0C
Explosive Limits 1.8- vol% in air
Solubility Slightly in CCl4, highly soluble in
Ethanol, diethyl ether, acetone.
Toxicity Harmful

52
Commercial stats of Nitrobenzene: Indian scenario
List of production plants
1. Tirupati Chemical Industries. Mumbai-
400097 ,India
2. Minda Petrochemicals P. LIMITED,
India
3. Pragati Chemicals Ltd. Mumbai-
400093 ,India. ...
4. Pyramid Chemicals. Mumbai- 400075
,India
Application
1. Aniline Production
2. Dyes and Pigments
3. Pesticides
4. Intermediate in Pharmaceuticals
5. Other Applications (including Solvent,
Explosives, etc.)
Production volume of Nitrobenzene in India from financial year 2013 to
2020 (in 1,000 metric tons)
https://www.statista.com/statistics/727809/india-nitrobenzene-production-volume//

Production of Nitrobenzene: Method
53
Nitration of Benzene in the presence of Sulphuric Acid
Chemical reactions
1. Benzene Nitration (main reaction)
𝑪𝟔𝑯𝟔 + 𝑯𝑵𝑶𝟑 → 𝑪𝟔𝑯𝟓𝑵𝑶𝟐 + 𝑯𝟐𝑶; ∆𝑯 = −𝟐𝟕 𝒌𝑪𝒂𝒍
2. Role of H2SO4
𝑯𝑵𝑶𝟑 + 𝟐𝑯𝟐𝑺𝑶𝟒 → 𝟐𝑯𝑺𝑶𝟒
−
+ 𝑯𝟑𝑶+
+ 𝑵𝑶𝟐
+
;
𝑪𝟔𝑯𝟔 + 𝑵𝑶𝟐
+
→ 𝑪𝟔𝑯𝟓𝑵𝑶𝟐 + 𝑯+
Catalyst: H2SO4

Production of Nitrobenzene: Flow scheme
54
Na2SO4
H2CO3

Production of Nitrobenzene: Process Description
55
1. The production of nitrobenzene by subjecting benzene to isothermal nitration with a mixture of nitric
acid and sulfuric acid.
2. Concentrated sulfuric acid has two functions: it reacts with nitric acid to form the nitronium ion, and it
absorbs the water formed during the reaction, which shifts the equilibrium to the formation of
nitrobenzene.
3. Feeding of benzene into Nitrator (a slight excess of benzene is added to avoid nitric acid in the spent
acid), then slowly feeding the mixed nitrating acid (60 wt.% H2SO4, 25 wt.% HNO3, 15 wt.% H2O), and
thereafter digesting the reaction mixture in the same vessel.
4. The temperature in the Nitrator held at 50 0C, governed by the rate of feed of Benzene.
5. It then entered into a separator tank from which a portion of spent acid removed from bottom, and the
crude nitrobenzene drawn off the top of the separator.

Production of Nitrobenzene: Process Description
56
6. The removed spent acid (sulfuric acid & water) enters to evaporator in order to concentrate the sulfuric
acid with fresh sulfuric acid (98 wt.%) and then with fresh nitric acid (64 wt.%) fed again to the nitrator.
7. The crude nitrobenzene (nitrobenzene, benzene, sulfuric acid &water) drawn from the top of the
separator and washed with the Sodium Carbonate in order to remove Sulfuric Acid from crude
nitrobenzene, followed by final washing with Calcium Sulfate (anhydrite) to remove the water.
8. The product topped in still to remove benzene and give pure product (96-99 wt. %).

Acetic Anhydride [ (CH3CO)2O ]
57
IUPAC Name Ethanoic anhydride
Common names Acetic acid anhydride
Acetyl acetate
Acetyl Oxide
Acetic Oxide
CAS Number 108-24-7
Registry Number)
Melting Point -73.1 0C
Colour Colourless
Odor Strong vinegar like smell
Flash point 49 0C
Solubility Low solubility in water forming Acetic
acid (2.6 gm/100 ml water). Forming
ethyl acetate with alcohol. Soluble in
Chloroform, Ether.
Toxicity Flammable

58
Commercial stats of Acetic Anhydride: Indian scenario
1. Jubilant Organosys Limited
2. Luna Chemicals Industries Pvt. Ltd.,
etc.
Application
1. Cellulose Acetate production (Cigarette
industry)
2. Tetraacetylethylenediamine (TAED) for
detergent
3. Aspirin production (Health sector)
4. Flavours, fragrances, dyes and
sweeteners
5. IED’s
Production volume of Acetic anhydride in India from financial year
2013 to 2020 (in 1,000 metric tons)
https://www.statista.com/statistics/727739/india-acetic-anhydride-production-volume/

Production of Acetic Anhydride: Method
59

Production of Acetic Anhydride: Flow scheme
60
Acetic acid

Production of Acetic Anhydride: Process Description
61
1. In this process the esterification step is carried out continuously in the kettle of a single distillation
column 1, with n-butyl acetate as internal entrainer and side decantation to remove water by line 4.
2. Internal entrainer is recycled to the column. Recycle acetic acid is fed to the kettle by line 2,
together with an at least equimolar quantity of methanol by line 3, and a mixture of methyl acetate
with some water and unreacted methanol is removed as head product by line 5 and passed directly
to the carbonylation reactor 6.
3. In the carbonylation reactor 6 the esterification product is reacted with carbon monoxide, fed to the
reactor by line 7, in the presence of a rhodium carbonylation catalyst recycled by line 13, a
promoter of methyl iodide recycled by line 12, and a co-promoter of N-methyl imidazole recycled
as quaternary ammonium salt by line 13.
4. The initial catalyst components are charged by line 8, which is also used for any subsequent make-
up.

Production of Acetic Anhydride: Process Description
62
5. The product of the carbonylation reaction consisting of predominantly acetic anhydride, acetic
acid, unreacted methyl acetate and some methyl iodide is passed by line 10 to the separation zone
11 in which it is separated into a low boiling overhead fraction containing carbonylation feed and
volatile promoter components which is recycled by line 12 to the carbonylation reactor 6, a high
boiling base product containing carbonylation catalyst components which is recycled by line 13 to
the carbonylation reactor 6, and a mixed acetic acid/acetic anhydride fraction which is withdrawn
as a liquid sidestream by line 14 and passed to the separation zone 15.
6. In zone 15 the acid/anhydride product is separated by fractional distillation into an impure acetic
acid overhead fraction, which is recycled by line 16 to the esterification reactor 1, and an acetic
anhydride product fraction which is withdrawn as a base product by line 17. The net acetic acid
product from line 16 may be further purified is desired.

Maleic Anhydride (C4H2O3)
63
IUPAC Name Furan-2,5-dione
Common names Maleic acid anhydride
2,5-Furandione
Cis-Butenedioic anhydride
CAS Number 108-31-6
Registry Number)
Melting Point 53 0C
Density 0.934 gm.cm-3 (at 20 0C)
Colour Colourless
Odor Irritating, choking smell
Flash point 102 0C
Solubility 16 wt% in Water, acetone, ether,
chloroform and petroleum
Toxicity Corrosive

64
Commercial stats of Maleic Anhydride: Indian scenario
Production volume of maleic anhydride in India from financial year
2013 to 2020 (in 1,000 metric tons)
https://www.statista.com/statistics/727852/india-maleic-anhydride-production-volume/
1. Thirumalai Chemicals Ltd
2. IG Petrochemicals Limited.
3. Huntsman International LLC
4. LANXESS
During FY2020, in India, the import
was more than 50 thousand tonnes,
which is almost 32 percent higher
compared to import in FY2019.
Application
Unsaturated Polymer Resin, Coatings,
Lubricant, Plastic Additives, Copolymers,
Malic Acid, Succinic Acid and Fumaric Acid
etc.

Production of Maleic Anhydride: Method
65
Oxidation of Benzene or n-Butene
Chemical reactions
1. Benzene Oxidation
𝑪𝟔𝑯𝟔 + 4
𝟏
𝟐
𝑶𝟐 → 𝑪𝟒𝑯𝟐𝑶𝟑 + 𝟐𝑯𝟐𝑶 + 𝟐𝑪𝑶𝟐; ∆𝑯 = −𝟒𝟐𝟐 𝒌𝑪𝒂𝒍
Reaction conditions Catalyst: V2O5
Temperature: 400-500 0C
Pressure: 0.8-1 atm
2. Butene Oxidation
𝑪𝟒𝑯𝟖 + 𝟑𝑶𝟐 → 𝑪𝟒𝑯𝟐𝑶𝟑 + 𝟑𝑯𝟐𝑶; ∆𝑯 = −𝟐𝟕𝟏 𝒌𝑪𝒂𝒍
3. Fumaric acid (Side reaction)
60 0C
→
+ +
→
Maleic Anhydride Maleic Acid Fumaric Acid
→
→
H2O H2O
Isomerisation
HCl

Production of Maleic Anhydride: Flow sheet
66
Plant Stats:
Plant capacity = 8-30 tons/day
a) Benzene basis
For 1 ton of Maleic Anhydride
(60% yield)
Benzene feed = 1.33 tons
Air = 20-22 tons
b) Butene basis
For 1 ton of Maleic Anhydride
(50% yield)
Butene feed = 1.07 tons
Air = 38-40 tons
1-1.5 atms
Fixed bed catalytic reactor
with contact time of 0.1 sec
Gravity
settler
40%
Azeotropic distillation
using Xylene as agent

Production of Maleic Anhydride: Process Description
67
Petrochemical product ends.

Pesticide Industry
Pesticide Market, Manufacturing processes of Pesticides

Pesticides
• Synthetic chemical compounds, dominantly used in agriculture sector to protect
crops, foods from insects, pests, weeds etc. at various stages in the sector.
• Part of agrochemical market.
• Agrochemicals
Need of the agriculture sector to meet the day-by-day increasing food demand of growing
population.
Help agriculture sector by increasing crop yield in the form of synthetic fertilizers.
Help to reduce crop yield loss because of insects, pests, weeds etc.. In the form of
pesticides.
Hazardous to human beings but at the same time boosted green revolution. 69

Indian Pesticide Industry
• Contributing significantly in Indian and World economy.
• Agriculture and public health sector.
• Industry’s Indian monetary valuation was already $3.8 billion in 2011 but reduced to $3
billion in 2020.
• Indian industry exports pesticides to USA, EU and African countries.
• 60 technical grades
• Minimum 125 producers including 10 multinational companies.
• First application of pesticides started for malaria control in 1948.
• First agricultural application was started in 1949.
70

Indian Pesticide Industry: Production
• First dedicated and indigenous production unit
was installed in 1954 for DDT
(Dichlorodiphenyltrichloroethane) and BHC
(Benzene Hexachloride - Lindane Isomer)
pesticides.
• Produces fungicides, herbicides, rodenticides,
miticides and nematicides.
• Initially produced as technical grade but later
converted into approved formulations (powder,
emulsions, concentrates etc.).
• Industry suffers from high inventory owing to
seasonal and irregular demands. 71
https://www.statista.com/statistics/726938/india-pesticides-production-volume/

Indian Pesticide Industry: Market
72

Indian Pesticide Industry: Influence
73
Pesticide consumption in
India is lower (600 g/ha)
than the global
consumption average
(3000 g/ha)
Area: Million hectares
Production: Kg/hectare

Pesticides: Classification
• The technical grade basis
74

• Based on Target
75

• Based on Chemical Groups
76

Pesticides: Manufacturing processes of few
77
Compounds Pesticide
Technical
grade
Book reference page
number
(Dryden’s outlines of
Chemical technology)
Dichlorodiphenyltrichlor
oethane (DDT)
Insecticides 546
Parathion Insecticide 548
2,4-
Dichlorophenoxyacetic
acid
Herbicide 548

Dichlorodiphenyltrichloroethane (DDT)
(C14H9Cl5)
78
IUPAC Name 1,1′-(2,2,2-Trichloroethane-
1,1-diyl)bis(4-chlorobenzene)
Common names DDT
CAS Number 50-29-3
Registry Number)
Technical Grade Insecticide
Melting Point 108.50 C
Boiling Point 260 0C
Density 0.99 gm.cm-3 (-200 C)
Color Colorless
Odor Odorless
Flash point 72-77 0C
Solubility Water 25 μg/L (25 °C)
Toxicty limit Dangerous, Carcinogenuc

Production of DDT
Ethanol and Benzene are the raw materials for DDT production.
Ethanol converted to Chloral first by either of following method:
• Oxidation of Ethanol to acetaldehyde followed by chlorination.
• Direct Ethanol chlorination using Chlorine.
 Chemical reaction
𝑪𝑪𝒍𝟑CHO + 𝟐𝑪𝟔𝑯𝟓𝑪𝒍 → (𝑪𝟔𝑯𝟒𝑪𝒍)𝟐𝑪𝑯𝑪𝑪𝒍𝟑 + 𝑯𝟐𝑶;
79
Chloral Chlorobenzene

Production of DDT: Flow sheet
80

Production of DDT: Process Description
 Ethanol converted to Chloral first by following method:
• Direct Ethanol chlorination using Chlorine.
 Chloral and Chlorobenzene are condensed using strong sulphuric acid (100%) or oleum as a
catalyst.
 Steel reactor (1000 gallons typically) providing reaction temperature of 15-30 0C for 5-6 hours.
 After condensation, spent acid is withdrawn, organic layer is water washed and neutralised by
soda ash.
 Produced DDT and unreacted chlorobenzene is then dried and separated in distillation column.
 Molten DDT then solidified and ground to powder.
81

Parathion (C10H14NO5PS)
82
IUPAC Name O,O-Diethyl O-(4-nitrophenyl)
phosphorothioate
Common names E605
CAS Number 56-38-2
Registry Number)
Technical Grade Insecticide
Melting Point 6 0C
Color Pale yellow to brown
Odor Faint odor
Flash point 120 0C
Solubility Water 24 mg/L (25 °C), high in Xylene
and Butanol
Toxicty limit Dangerous, Carcinogenuc

Production of Parathion
Diethyl Phosphorochlorido-Thionate and Sodium p-nitro Phenoxide are
the raw materials.
Phosphorus containing reactant is obtained from PSCl3 and Ethanol.
Chemical reaction
(𝑬𝒕𝑶)𝟐PSCl + 𝑵𝒂𝑶𝑪𝟔𝑯𝟒𝑵𝑶𝟐 → (𝑬𝒕𝑶)𝟐𝑷𝑺𝑶𝑪𝟔𝑯𝟒𝑵𝑶𝟐 + 𝑵𝒂𝑪𝒍;
83
Diethyl Phosphorochlorido-Thionate
(𝑬𝒕𝑶)𝟐PSCl
(𝑬𝒕𝑶)𝟐𝑷𝑺𝑶𝑪𝟔𝑯𝟒𝑵𝑶𝟐

Production of Parathion: Flow sheet and process description
84
 Reaction takes place into a jacketed and well
stirred reactor.
 Benzene, alcohol or chlorobenzene can be used
as solvent.
 Copper powder used as catalyst. Or reaction
vessel made of carbon can be used.
 90% or higher yield Parathion can be obtained.
 Gummy impurities removed at precoated filter
from the product crude.
 Filter then separated into aqueous and heavy
oil layer.
 Oil layer then washed and distilled to remove
unreacted materials.
 Final product dried under vacuum and wwhich
is a yellowish liquid Parathion.

2,4-D (C8H6Cl2O3)
85
IUPAC Name 2-(2,4-dichlorophenoxy)acetic acid
Common names Hedonal, trinoxol
CAS Number 94-75-7
Registry Number)
Technical Grade Herbicide
Melting Point 140.5 0C
Color White to yellow powder
Odor Odorless
Flash point Nonflammable
Solubility Water 900 mg/L (25 °C)
Toxicty limit Dangerous

Production of 2,4-D
Dichlorophenol and Monochloroacetic acid are the raw materials.
Chemical reaction
𝑪𝒍𝟐𝑪𝟔𝑯𝟑𝑶𝑯 + 𝑵𝒂𝑶𝑯 → 𝑪𝒍𝟐𝑪𝟔𝑯𝟑𝑶𝑵𝒂 + 𝑯𝟐𝑶;
𝑪𝒍𝑪𝑯𝟐𝑪𝑶𝑶𝑯 + 𝑵𝒂𝑶𝑯 → 𝑪𝒍𝑪𝑯𝟐𝑪𝑶𝑶𝑵𝒂 + 𝑯𝟐𝑶;
𝑪𝒍𝟐𝑪𝟔𝑯𝟑𝑶𝑵𝒂 + 𝑪𝒍𝑪𝑯𝟐𝑪𝑶𝑶𝑵𝒂 → 𝑪𝒍𝟐𝑪𝟔𝑯𝟑𝑶𝑪𝑯𝟐𝑪𝑶𝑶𝑵𝒂 + 𝑵𝒂𝑪𝒍;
𝑪𝒍𝟐𝑪𝟔𝑯𝟑𝑶𝑪𝑯𝟐𝑪𝑶𝑶𝑵𝒂 + 𝐇𝐂𝐥 → 𝑪𝒍𝟐𝑪𝟔𝑯𝟑𝑶𝑪𝑯𝟐𝑪𝑶𝑶𝑯 + 𝑵𝒂𝑪𝒍
86
2,4-D

Production of 2,4-D : Flow sheet and process description
87
 Reaction takes place into a jacketed and well
stirred reactor.
 Sodium Hydroxide was fed to the reactor with
the reactants.
 Reaction carried out at 60-80 0C and for the
duration of 6-8 hours.
 Reaction products pass from reactor to the
holding tank.
 Then enamle-lined ph regulator tank regulate
the pH.
 Next stage is brick lined still where products
enteract with steam to remove unreacted 2,4-
dichlorophenol.
 Then a sequence of holding tank, filter and
dryer followed and finally a crystalline
herbicide product produced.
Pesticides lecture end

Fuel and Industrial Gases
Application and Manufacturing processes

Syllabus
89
Gases Technical grade Book reference page
number
(Dryden’s outlines of
Chemical technology)
Producer Gas Fuel Gas 71
Synthetic Gas Fuel Gas 80
Pyro Gas Fuel Gas
Nitrogen Industrial Gas 100
Oxygen Industrial Gas 100
Carbon Di-Oxide Industrial Gas

Fuel Gases
• Gaseous fuels at ordinary conditions.
• Main constituents: Hydrocarbons (Methane or Propane), Hydrogen, carbon monoxide
or mixtures of these gases.
• Source of heat energy or light and can be easily transported through dedicated
pipelines.
• Industrial use of fuel gasses: Energy or Synthesis of some inorganic and organic
chemical compounds.
• Water, air, coal, natural gas and petroleum are the main sources to obtain these fuel
gases.
90

Fuel Gases: Classification
91
Fuel Gases
Types Producer Gas Water Gas Coke Oven Gas Carburetted or
Oil Gas
Natural Gas and
LPG
Constituents CO, N2, H2, with
steam
CO, H2 H2, CH4, CO Water gas and
Pyrolyzed Oil
Liquefied
Petroleum Gas
kCal.m-3 1,200-1,600 2,500-2,700 4,500-8,000 4,000-9,000 6,000-14,000
Application Steel industry’s
heating
requirements
(heat treat, coke
ovens)
Heating,
Chemical
Synthesis
Heating,
Chemical
Synthesis
Heating Heating,
Chemical
Synthesis

Fuel Gases: Chemical reactions
92
1. 𝑪 𝒔 + 𝑶𝟐 𝒈 𝒆𝒙𝒄𝒆𝒔𝒔 𝒂𝒊𝒓 → 𝑪𝑶𝟐 𝒈 ; ∆𝑯𝟎
= −𝟗𝟔. 𝟓 𝒌𝑪𝒂𝒍
2. 𝟐𝑪 𝒔 + 𝑶𝟐 𝒈 𝒍𝒊𝒎𝒊𝒕𝒆𝒅 𝒂𝒊𝒓 → 𝟐𝑪𝑶 𝒈 ; ∆𝑯𝟎
= −𝟓𝟕. 𝟖 𝒌𝑪𝒂𝒍
3. 𝑪 𝒔 + 𝑪𝑶𝟐 𝒈 → 𝟐𝑪𝑶 𝒈 ; ∆𝑯𝟎
= +𝟑𝟖. 𝟕 𝒌𝑪𝒂𝒍
4. 𝑪 𝒔 + 𝑯𝟐𝑶 𝒍 → 𝑪𝑶 𝒈 + 𝑯𝟐 𝒈 ; ∆𝑯𝟎
= +𝟑𝟖. 𝟗 𝒌𝑪𝒂𝒍
5. 𝑪𝑶 𝒈 + 𝑯𝟐𝑶 𝒍 → 𝑪𝑶𝟐 𝒈 + 𝑯𝟐 𝒈 ; ∆𝑯𝟎
= +𝟎. 𝟒 𝒌𝑪𝒂𝒍

Producer Gas (CO, N2, H2 with steam )
93
Applications: Steel Industry, Heat Treat, Coke ovens
Raw materials
 Coal or blast furnace coke
 Air
Quantitative requirements
 Basis: 100 Nm3 of producer gas
Coke 20-25 Kg or Coal 25-30 Kg
Steam 8-10 Kg
Air 60-80 Nm3
 Plant capacities: 25,000-250,000 m3/day

Producer Gas: Process description and Major
Engineering problems
95
Process Description
Steam and air mixture injected in bottom
of water-cooled jacketed steel furnace
equipped with a rotating grate to remove
fusible ash.
Solid fuel is added from hopper valve on
top of furnace.
Producer gas is cooled by passing through
a waste heat boiler.
Major Engineering problem
 Design of suitable gas producer furnace to:
• Keep uniform fuel surface.
• Provide adequate gas-fuel contact time at
high temperature.
• Avoid clinkering and provide for proper
fused ash removal.
 Addition of correct steam quantities to supply
net heat of reaction near zero on a continuous
once-through process

Synthesis (Syn) Gas (CO, H2 and may be CO2 )
96
Applications: Heat and Chemical synthesis
Different from Water gas which does not contain any CO2.
In special cases CO is replaced/removed by particular gases as following
: Ammonia synthesis gas (3H2 + N2)
: Hydrogenation of Coal (H2 only)

Synthesis (Syn) Gas: Application in chemical
synthesis
97
 Other major
products:
• Ammonia
• Hydrogenation
compounds
 Over 90%
produced H2 used
for NH3
production.

Synthesis (Syn) Gas: Methods of Production
98
 Can be classified in two types of processes
 From petroleum hydrocarbons
Reforming (Method I)
Partial Combustion (Method II)
 From coal or coke
Water Gas
Coke Oven Gas
 Chemical Reactions (Steam reforming process)
 Reforming reactions
𝑪𝒏𝑯𝟐𝒏+𝟐 + 𝒏𝑯𝟐𝑶 ՞
𝑵𝒊
𝒏𝑪𝑶 + 𝟐𝒏 + 𝟏 𝑯𝟐; ∆𝑯𝟎
= ቊ
𝟓𝟐 𝐤𝐂𝐚𝐥 𝐟𝐨𝐫 𝐧 = 𝟏
𝟐𝟑𝟖 𝐤𝐂𝐚𝐥 𝐟𝐨𝐫 𝐧 = 𝟔,
𝐂𝐎 + 𝟑𝑯𝟐 ՞ 𝑪𝑯𝟒 + 𝑯𝟐𝑶; ∆𝑯𝟎= −𝟓𝟐. 𝟎 𝐤𝐂𝐚𝐥
 Water gas shift reaction
𝐂𝐎 + 𝟑𝑯𝟐
𝑭𝒆𝑶
𝑪𝑶𝟐 + 𝑯𝟐𝑶; ∆𝑯𝟎
= −𝟗. 𝟖𝟎𝟔 𝐤𝐂𝐚𝐥

Synthesis (Syn) Gas: Method I
99
Raw materials (Steam reforming process)
 Refinery naphtha or off-gases
 Air (Optional)
 Steam
 Small makeup quantities of nickel and promoted iron oxide catalyst,
ethanolamines and ammoniacal cuprous formate
 Basis: 100 Nm3 of H2 of 99+% purity
Naphtha 21.9 kg
Steam 560 Kg
Fuel (as naphtha) 22.3 kg
Cooling water 6.5 tons
 Plant capacities: 10-200 tons/day of H2
80,=3000-1,680,000 Nm3/day of Synthesis gas

Synthesis (Syn) Gas: Flow sheet (Method I)
100

Synthesis (Syn) Gas: Process Description
(Method I)
101
1. Hydrocarbon feed and steam fed to the reforming furnace. Reformer is Ni catalysed packed in
vertical tubes (3-4 inches dia * 20-25 ft length).
2. Combustion gasses is supplied to the furnace to support endothermic reactions.
3. Reaction temperature maintained at 700-1000 0C, in high temperature alloy steel tubed and
refaractory lined steel walled furnace.
4. Space velocity maintained at 500-600/hr.
5. After the reformer, all 3 synthesis gases can be produced as following:
i. For CO-H2 synthesis gas
The effluent gas from reformer is cooled at 35 0C and pumped to a hot potassium
carbonate scrubbing system to remove CO2.

Synthesis (Syn) Gas: Process Description
(Method I)
102
5. After the reformer, all 3 synthesis gases can be produced as following:
ii. For H2 gas
A water-gas shift converter is used to remove CO and form more H2 as per water-
gas shift reaction. Reformer effluent gas quenched with steam fed to catalytic
converter using iron oxide as catalyst promoted with chromium oxide at 350 0C.
Space velocity maintained at 100-200/hr. After CO2 removal, traces of CO are
removed by methanation reaction. For high purity hydrogen (99.9%) one or more
additional stages of shift converter, CO2 absorber can be added.
iii. For NH3 synthesis gas
Correct amount of Nitrogen for NH3 synthesis gas is added via air and O2 is burned
out by hydrogen in a Ni catalysed combustion chamber inserted immediately after
reformer. Effluent gases are cooled to 350 0C by a water quench tower and then
passed to the shift converter. Except for the additional N2 which passes through
remainder of the process is same as H2 preparation

Synthesis (Syn) Gas: Major engineering
problem (Method I)
103

Synthesis (Syn) Gas: Methods of Production
104
Raw materials (Partial Combustion)
 Lower purity natural gas than required for steam reforming; can use cheap liquid
hydrocarbon also
 Tonnage Oxygen (Low-purity grade)
 Steam
 Small makeup quantities of nickel and promoted iron oxide catalyst,
ethanolamines and ammoniacal cuprous formate
 Basis: 100 Nm3 of H2 of 99+% purity
Naphtha 29.2 kg or Methane 35 Nm3
Steam 104 Kg
Oxygen 26 Nm3
Cooling water 8 tons
 Plant capacities: 10-200 tons/day of H2
10,000-1,600,000 Nm3/day of Synthesis gas

Synthesis (Syn) Gas: Flow sheet Method II
105
Chemical Reactions
𝑪𝑯𝟒 + 𝟐𝑶𝟐 → 𝑪𝑶𝟐 + 𝟐𝑯𝟐𝑶;
𝑪𝑯𝟒 + 𝑯𝟐𝑶 → 𝑪𝑶 + 𝟑𝑯𝟐;
𝑪𝑯𝟒 + 𝑪𝑶𝟐 → 𝟐𝑪𝑶 + 𝟐𝑯𝟐
Net reaction
𝟑𝑪𝑯𝟒 + 𝟐𝑶𝟐
→ 𝟑𝑪𝑶 + 𝑯𝟐𝑶 + 𝟓𝑯𝟐; ∆𝑯 ≅ 𝟎

Synthesis (Syn) Gas: Process Description (method II)
106

Synthesis (Syn) Gas: Major engineering
problems (method II)
107

Pyro Gas
Manufacturing processes and Application

Pyrolysis
• Pyrolysis is a thermo-chemical decomposition of
organic material into liquid (bio-oil), gases (pyro
gas) and char (bio char) at elevated temperature in
the absence of Oxygen (or any Halogen).
• Changes in chemical, physical composition and
changes are irreversible.
• Pyrolysis does not involve reactions with Oxygen,
Water, or any other reagents.
• A small amount of oxidation occurs because in any
pyrolysis system, complete Oxygen-free
environment is not possible.

Pyrolysis raw material
• Biomass: Obtained directly from plants-animals,
and indirectly from industrial, commercial,
domestic or agricultural products.
• Specifically
Agricultural waste (Eg. Crop and vegetable residuals,
rice husk, straw)
Livestock: Butchery waste, bone material, dead animals
Forestry: Sawdust, processing waste
Fishery
Industrial and house hold organic residuals (Sewage
sludge, waste food etc.)

Pyro gas
Mainly a form of Syn gas,
consisting of Carbon Monoxide and
Hydrogen (85%) and with smaller
amounts of CO2 and Methane.
High in calorific value
Possess less than half the energy
density of natural gas.
Pyro gas: Production
method
Depending upon the thermal
environment and the final temperature,
pyrolysis will yield:
1. Mainly biochar at low temperatures,
less than 450 0C, when the heating rate
is quite low.
2. Mainly gases (Pyro gas) at high
temperature, greater than 800 0C, with
rapid heating rates
3. At an intermediate temperature and
under relatively high heating rates, the
main product is bio-oil.

Pyro gas is a form of Syn gas.
Chemical reactions involved: "𝑠𝑖𝑚𝑖𝑙𝑎𝑟 𝑡𝑜 𝑺𝒚𝒏 𝑮𝒂𝒔"
Application: "𝑠𝑖𝑚𝑖𝑙𝑎𝑟 𝑡𝑜 𝑺𝒚𝒏 𝑮𝒂𝒔"
Pyro Gas: Chemical Reaction and
applications

Carbon Di-Oxide (CO2) (M.W.= 44.01)
115
A colorless gas in environment with trace amount presence of 0.04 vol% (412 ppm).
A Gree House Gas with sharp acidic odor generates soda water taste in mouth
Jan Baptist Van Helmort first observed this non-flammable gas during burning of
charcoal in the closed vessel and termed it “wild spirit”.
Properties of this gas was studied by Joseph Black in 1750.
Humphry Davy and Michael Faraday first liquefied CO2 at elevated pressure in
1823.
In 1834, Charles Thilorier solidifies CO2, in pressurized container of liquid carbon
dioxide.
Melting point = -56.5 0C; Boiling Point = -78.48 0C; Density = 1.799 g/L

Carbon Di-Oxide: Natural
116
CO2 is an end product in organisms (mostly all living beings) that obtain energy from
breaking down sugars , fats and amino acids with oxygen as part of their metabolism,
in a process known as cellular respiration. (Production)
𝐶6𝐻12𝑂6 + 6𝑂2 → 6𝐶𝑂2 + 6𝐻2𝑂 + 𝑒𝑛𝑒𝑟𝑔𝑦
 Also produced by fermentation of liquids, breathing of animals, volcanoe emissions,
hot springs and from carbonate rocks by dissolution. (Production)
 Present in atmosphere, ground water, rivers, lakes, icecaps, sea water and deposits of
petroleum and natural gas. (Storage)
 Plants, algae and Cyanobacteria consume CO2 to produce carbohydrate energy for
themselves and O2 as a waste product. (Application)

Carbon Di-Oxide: Industrial production
117
1. By burning of carbonaceous materials
𝑪 + 𝑶𝟐 → 𝑪𝑶𝟐 + 𝒆𝒏𝒆𝒓𝒈𝒚
2. In the production of H2 by steam reforming of methane or other hydrocarbons (16%
purity)
𝑪𝑯𝟒 + 𝟐𝑯𝟐𝑶 → 𝑪𝑶𝟐 + 𝟒𝑯𝟐
3. In manufacture of alcohol (ethanol) by the fermentation process (99.9% purity)
𝑪𝟔𝑯𝟏𝟐𝑶𝟔 → 𝑪𝑶𝟐 + 𝑪𝟐𝑯𝟓𝑶𝑯
4. In calcinations of CaCO3 at 1000 0C (40% purity)
𝑪𝒂𝑪𝑶𝟑 → 𝑪𝑶𝟐 + 𝑪𝒂𝑶
5. Sodium phosphate manufacturing
𝟑𝑵𝒂𝟐𝐂𝑶𝟑 + 𝟐𝑯𝟑𝑷𝑶𝟒 → 𝟑𝑪𝑶𝟐 + 𝟐𝑵𝒂𝟑𝑷𝑶𝟒 + 𝑯𝟐𝑶

Carbon Di-Oxide: Manufacturing
118
1. By burning of carbonaceous material: Cake or Coal (10-18% purity)
𝑪 + 𝑶𝟐 → 𝑪𝑶𝟐; ∆𝑯 = −𝟐𝟑. 𝟏𝟔 𝒌𝑪𝒂𝒍𝒔

Carbon Di-Oxide: Process description
119
1. Coke, coal, fuel or gas is burned under a standard water- tube boiler for the production of 200-250 psig steam.
2. The flue gases containing 10-18% CO2 are taken from the boiler at 345 oC and passed through two packed
towers where they are cooled and cleaned by water.
3. After passing through the scrubbing towers, the cooled flue gases pass through a booster blower and into the
base of the absorption tower in which CO2 is absorbed selectively by a solution of ethanolamines passing
countercurrent to the gas stream.
5. The CO2 bearing solution passes out of the bottom of the absorption tower are sprayed from the top of a
reactivation tower.
6. Where CO2 is stripped from the amine solution by heat and the reactivated solution returns through the heat
exchanger equipment to the absorption tower.
7. CO2 and steam pass out through the top of the reactivation tower into a gas cooler in which the steam
condenses and returns to the tower as reflux.
8. CO2 gas is stripped out at the pressure of about 300 psig. If liquid or solid CO2 is desired, it may be further
purified for odor removal before compression.

Carbon Di-Oxide: Recovery option
120

Carbon Di-Oxide: Purification
121
 Recovered CO2 are always in the impure state often mixed with CO, N2,water vapours and
other flue gases.
 Purification of CO2 can be classified in following two categories
1. Purification of low% CO2 containing gas
2. Purification of high% CO2 containing gas

Carbon Di-Oxide: Purification
122

Carbon Di-Oxide: Industrial application
123
 As solid CO2 in refrigeration process
 Liquid CO2 in carbonated beverages
 In creating inert atmosphere
 As fire extinguisher
 Gaseous CO2 as a neutralizing agent (alkaline solution)
 As a basic raw material for the production of Methanol, Urea, Na2CO3 and
NaHCO3

Oxygen (O2) and Nitrogen (N2)
125
O2 N2
Chemical structure
Molecular weight 32 28.02
Boiling Point -183 0C -195.8 0C
Melting Point -218.8 0C -210 0C
Density 1.429 g/L 1.2506 g/L
Commercial Grades High purity (99.5% O2, 0.5%
Ar)
Low Purity (90-95% O2, 4-5%
Ar, rest N2, CO2)
Technical (99% N2, rest Ar and
O2)

Oxygen (O2): Introduction
126
 A pale blue, odourless, tasteless gas present in the air in vol% of 20.95.
 A strong oxidizing agent, boasting second highest electro negativity.
 Discovered by Carl Wilhelm Scheele and Joseph Priestley in 1773 and 1774 with forst work publication
by Priestley.
Nitrogen (N2): Introduction
 A colorless, odourless, tasteless gas present in the air in vol% of 78.09.
 Human body contains about 3% of N2 by weight in forms of amino acids, protiens and nucleic acids.
 Discovered by Daniel Rutherford in 1772 and called it Noxious air or fixed air.

127
Oxygen (O2) and Nitrogen (N2): Methods of
production
 All major production methods are based on liquefaction of air and subsequent fractional distillation of
liquefied air.
 Liquefaction of air is the application of either of following two basic thermodynamic basic cycles
1. Linde Cycle: Uses refrigeration by Joule-Thompson cooling (Low purity)
2. Claude Cycle: Obtains refrigeration by adiabatic expansion of compressed air in a turbo-
reciprocating or rotating expansion machine.
 Method to be discussed here is using Linde and Linde-Frankl cycle.

130
Oxygen (O2) and Nitrogen (N2): Methods of
production
Linde-Frankl Cycle (Low purity)
 Chemical Reaction involved
CO2 scrubbing reaction: 𝟐𝑵𝒂𝑶𝑯 + 𝑪𝑶𝟐 → 𝑵𝒂𝟐𝑪𝑶𝟑 + 𝑯𝟐𝑶
 Raw Materials
1. Air (of usual composition)
2. NaOH, NH3 and silica gel in small quantities
 Quantitative requirements
a) Basis: 1 ton of 95% O2 in 300 tons/day plant
Air: 3,600 Nm3
Steam: 1.75 tons
Cooling water: 5 tons
b) Plant capacity: 50-500tons/day

131
Oxygen (O2) and Nitrogen (N2): Flow sheet (low purity)

132
O2 and N2: Process Description (low purity)
1. Compressed air (4-5 atms) cooled with H2O passed to regenerative exchangers.
2. Regenerative exchangers are cylindrical pressure vessels packed with aluminium spirals operating in
pairs.
3. Air is cooling in one vessel while cold product gas (O2 or N2) is removing sensible heat from packing in
the other.
4. After 2-4 minutes cycle is reversed by automatic valves.
5. Air entering the cold exchanger contains both H2O and CO2 which must be removed before entering
fractionation section operating at -183 to -195 0C to prevent plugging.
6. These impurities are removed on the cold packing throughout the exchanger and then product gas which
starts with zero concentration of H2O and CO2 and thus provides an equilibrium driving force for the
vaporization process.
7. Both the O2 and N2 product gas necessarily contain H2O and CO2 impurities in this type of cycle design
and only low purity O2 can be obtained.

133
8. The air leaving the regenerative heat exchangers is cooled at -170 0C and fed to the reboiler section of
the double column where further cooling takes place.
9. The double column is in fact two distillation columns with a low pressure (1.4 atms.) column standing
on the top of the high pressure (5.7 atms.) column, the reboiler of the upper column working as the
condenser for the vapors from lower column.
10. In the high pressure section, the more volatile Nitrogen works its way to the top of the column and is
condensed inside of the tubes of the reboiler section of the low pressure column by the liquid oxygen
surrounding the tubes.
11. This is accomplished because the temperature of liquid oxygen at 1.4 atms. Is lower than the
condensation temperature of the saturated nitrogen vapor at 5.7 atms.
12. This condensed nitrogen is then sprayed into the ytop of the low pressure column for reflux.
13. The less volatile O2 still containing 50% N2 is pumped to the middle of the low pressure column where
final rectification takes place.

134
14. The removal of Ar which boils 2.9 0C lower than O2 requires a much larger number of plates in columns.
Such designs used only for high purity O2 product.
15. To provide heat balance and flow control, a 3-6% side stream is drawn from the compressed air before
entering the regenerators.
16. This air is dried and freed of CO2 by the NaOH scrubbing tower.
17. The purified air is next compressed to 200 atms. cooled by H2O, NH3 refrigeration and N2 product heat
exchange before entering a turbo-expander operating on the Claude principle.
18. This balancing stream of cold air is fed near the bottom of the low pressure column.

Oxygen (O2) and Nitrogen (N2): Method of production
(High Purity)
Cycle for producing high purity O2: Kellogg cycle
 The major difference between this cycle and Linde-Frankl cycle is the use of a recuperative-
reversing heat exchanger.
 These are built in aconcentric triple-tube design with high purity oxygen moving through the inner
tube, never contacting the incoming air; known as recuperative heat exchange.
 The reversing principle is used to remove CO2 and H2O from the incoming air stream by switching
the flow of the N2 product stream and the air stream in the outer two annuli.
 A catalytic oxidation chamber inserted after the initial compression to 70 psig to convert
hydrocarbons to CO2 and H2O
 Silica gel filter ahead of the double column
135

Oxygen (O2) and Nitrogen (N2): Flow sheet(High
Purity)
136
Unit 2 has been completed here.

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