Petroleum and Petrochemicals Children’s Club lecture T. Nithya

Introduction to Petroleum  M Modern Industrial organic chemistry UUses are restricted, unless it is refined to several products Formed Earth’s surface, millions of years ago Major source for fuels and various raw materials

Almost 90% is used for transportation and heat generation and electricity and remaining is feedstock's for chemical industry

What is Petroleum? Petra - rock & Oleum - Oil is called Petroleum Greenish Brown viscous liquid Volatile, flammable liquid Lower to higher molecular weights hydrocarbons and various hydrocarbons Trace amounts of metals (Fe, Ni, Cu & V) Divided into three parts Light distillates (LPG, Gasoline and naphtha) Middle distillates (Kerosene, diesel) heavy and residuum (wax, asphalt, heavy fuel oil)

What are hydrocarbons? Organic compounds that contains only hydrogen and carbon Have single (alkanes), double(alkenes) and triple(alkynes) bonds The most common example : methane Easily burns in air and produce CO 2, water and also produce heats Methane + 2O 2  CO 2 + 2H 2 O + heat CH 4 gases C 5 H 12 liquids C 4 H 10 C 17 H 36 C 18 H 38 solids

Alkanes

Structure of Alkanes  C-C and C-H single bonds  General formula C n H 2n+2 Straight chain alkanes All carbons connected in a row Branched chain alkanes Branching connection of carbons Alkanes forms constitutional isomers : Same molecular formula but different arrangement of atoms

Alkenes  Also called olefins  C=C double bonds  General formula C n H 2n constitutional isomers Example is ethylene Cis-butene Trans-butene

Saturated and unsaturated Compounds  S Saturated - No double or triple bonds  Alkanes are belongs to saturated compounds  U Unsaturated - degree of unsaturation defines the amount of hydrogen that a compound can bind.  Contains double and triple bonds  Alkenes and Alkynes are unsaturated compounds

Hydrocarbon Rings  Alkanes and alkenes also forms ring structure  For example cyclopentane (C 5 H 10 ), cyclopentane (C 5 H 8 ), cyclohexane (C 6 H 12 ), cyclohexene (C 6 H 10 ), benzene (C 6 H 6 ). (C 6 H 6 )(C 6 H 12 ) (C 6 H 10 )

How were fossil fuels formed? Oils were formed more than hundred million years ago under the ocean or lakes - plankton When the plankton died, it sank to the bottom of sea or lake Died plankton mixed with mud in the sea or lake-Oxygen deficiency the plankton did not decompose fully Organic matters buried deeper and deeper – temperature and pressure increased Due to high temp. and press. Buried organic compounds to shorter chain HC(Oil). After formation, oil starts to migrate from source rock to upword when the migration stopped, the oil fields created.

Extraction of Petroleum Locating oil fields - Seismic surveys, gravimeters & magnetometers Drilling a hole into the earth. The oil is thicker or heavier then steam is applied ( °C ) to force the oil to the surface

Petroleum Refining  An industrial process  Refined into useful products  Involves three major process  S Separation : petroleum into simpler fractions after the removal of unwanted materials by distillation  C Conversion : separated fractions are further converted into useful products by cracking, reforming, alkylation and Isomerization.  F Finishing : purification of the products from all fractions

Properties of Crude oil NameMajor productApproximate boiling range (°C) LPG; liquified petroleum gas C 4 and some C 3 hydrocarbons below 0 Petrol (gasoline)C 5 to C 9 aromatic rich30 to 160 Kerosene/ Aviation turbine fuel (ATF) C 10 to C 15 alkane rich150 to 270 DieselC 14 to C 19 alkane rich260 to 360 Lubricating oilsC 20 to C 40 non aromatic300 to 550 Non n-paraffinic Was C 20 to C 40 n-alkanes> 300

Distillation of Crude oil Principle : difference in the boiling points of the various fractions of petroleum. Method : Fractional distillation. a l l o w t h e v a p o r s t o r i s e u p a n d n o t d e s c e n d d o w n

Uses of Petroleum products The obtained petroleum products are used for various applications.  Domestic fuel (LPG)  Production of H 2  Production of carbon block  F u e l f o r H M v e h i c l e s  G e n e r a t i n g e l e c t r i c i t y r e a s e, w a x e s, v a s e l i n e ( l u b r i c a t i n g m a c h i n e p a r t s )  t a r f o r r o a d s u r f a c e  A v i a t i o n f u e l ( a i r p l a n e )  D o m e s t i c f u e l s t o v e s  i l l u m i n a t i o n l a m p s

Uses of Petroleum products  Energy production  fuel burns produce heat (Exothermic)  To produce electricity (heat is used to convert water into steam, it helps to runs turbine that generates electricity)  F For example, LPG & CNG burns Chemical energy Heat Mechanical energy Electricity

Cracking Product may contain C=C bonds also Further alkylated or isomerizes in order to get desired product. Mainly, catalysts have used for this process. The catalysts mostly Zeolite Z e o l i t e s ( C o n t a i n s S i, A l & O a t o m s ) Cracking: larger and heavier hydrocarbons to smaller and useful products.

Thermal crackingCatalytic cracking Hydro cracking MModern cracking CCatalysts - alter the rate of reaction without affecting the reaction. ZZeolites catalyst (alumino silicates)  T & P ( °C & low P) RResults : LPG, Petrol, etc.,  presence of H2 & also catalysts  catalyst Ni-W on silica- alumina support or Pt or Pd on zeolites RResults : increase the yield of Petrol.

Cracking AAncient method of cracking. HHigh T ( °C) & P (70 atm) RResults distillate fuels and petrol Free radical mechanism Thermal Cracking

Reforming llow octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline OOctane number - measure of its resistance to knock. DDetermined by comparing the characteristics of a gasoline to isooctane (2, 2, 4-trimethylpentane) and heptane. Octane number  p presence of a catalyst and a high partial pressure of hydrogen.  T (495 to 525 °C ) and pressures ( 5 to 45 atm)

Reforming RReformation also done by catalysts contain platinum or rhenium on a silica or silica-alumina support base, and some contain both platinum and rhenium  Results low-octane naphtha into a high-octane reformate for gasoline blending and/or to provide aromatics (benzene, toluene, and xylene) for petrochemical plants. D e h y d r o g e n a t i o n : c o n v e r s i o n m e t h y l c y c l o h e x a n e ( a n a p h t h e n e ) t o t o l u e n e ( a n a r o m a t i c )

Reforming I s o m e r i z a t i o n : c o n v e r s i o n o f n o r m a l o c t a n e t o 2, 5 - D i m e t h y l h e x a n e ( a n i s o p a r a f f i n ) A r o m a t i z a t i o n : c o n v e r s i o n o f n o r m a l h e p t a n e t o t o l u e n e

Petrochemicals Introduction  Feed stocks for petrochemicals are gas and light to middle petroleum liquids  Nearly all the petrochemicals are produced over catalysts  Primary petrochemicals are divided into three types depending on their chemical structure

Petrochemicals Chemicals from methane

MeOH  acetic acid  Vinyl acetate Ethylene  ethylene oxide  ethylene glycol Ethylene  acetic acid Ethylene  ethyl alcohol Ethylene  vinyl chloride Propylene  propylene oxide  Propylene glycol Propylene  acrylic acid ; acrylonitrile Propylene  allyl chloride  epichlorohydrin  propylene oxide Butenes  Maleic anhydride

Petrochemicals (uses of benzene) Nitrobenzene Cyclohexane Cumene Ethylbenzene Benzene  Maleic anhydride Benzene  Chlorination; nitration etc. p-Xylene  Terephthalic acid o-Xylene  Phthalic acid

Petrochemicals (uses of toluene)

Petrochemicals Cyclohexane  cyclohexanol + cyclohexanone Cyclohexanone  Cyclohexanoneoxime  Caprolactam  Nylon-6 Cyclohexanol  adipic acid  Nylon-6,6 Cumene  Phenol + acetone Ethylbenzene  styrene  Many polymers are derived from the above petrochemicals  Hundreds of other chemicals are derived from olefins, BTX, phenol, acetic acid, methanol etc. Benzene + propylene  Cumene

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