PETROLEUM & NATURAL GAS

CHEMICAL PROCESSES & SUSTAINABILITY

Course Outcome:CO1:

The ability to describe the process and utility requirements in major chemical engineering industries and identify its importance.

Course Learning Outcome:Define petroleum, hydrocarbon and non-

hydrocarbonDiscuss the principal forms of petroleumIdentify the major constituents of petroleumIdentify the activities in petroleum industryExplain the purpose of refiningIdentify the process of refiningExplain the purpose and the process of

petroleum refiningIdentify the products of refining

HISTORY OF OIL AND GAS INDUSTRY

Development of energy sources:

From Industrial Revolution to today’s energy

What is the major energy source in the world?

HISTORY OF OIL AND GAS INDUSTRY

• Machineries invented

• Limiting factor: continual power source to run them

1700s

• Steam engine invented – major fuel firewood

• Power source for steamships, locomotives and textile mills

Late 1700s

• Coal replace firewood

• Coal replace firewood

• Coal also used for heating, cooking, industrial process

• Limiting factor: Environmental problem

• Invention of internal combustion engine (cars)

• Oil-well drilling

Late 1800s

•Fuel and natural gas dominant

1940s•Wind power•Hydroelectric•Solar enery•biofuels

Today

HISTORY OF OIL AND GAS INDUSTRY IN MALAYSIA

1909 – Oil was first discovered by Shell1974 - PETRONAS1975 – Petroleum Development Act

615,000 square km of available oil36% are covered by production sharing

contracts

DEFINITION: PETROLEUM

Petroleum: A form of bitumen composed principally of hydrocarbons which exists in the gaseous or liquid state in its natural reservoirs.

Petroleum = Hydrocarbon Compound + Non-Hydrocarbon Compound

COMPOSITION

Hydrocarbon (HC)

Organic Compund

O2, N2, Sulphur

H2, C

HYDROCARBON

Hydrocarbon can be found as:

(i) Natural gases. e.g. methane, ethane

(ii) Liquid. e.g. liquid crude, medium crude and heavy crude

(iii) Semi-solid. e.g. asphalts, waxes

Principal forms of petroleum are:

(i) Crude oil

(ii) Natural gas

(iii) Condensate

(iv) Asphalt

ORIGIN OF PETROLEUM

What is the process involve in formation of oil and gas?

THEORY

ORGANIC INORGANIC

Principle form of petroleum

Crude Oil

A mixture of hydrocarbons that exists in the liquid phase in natural underground reservoirs and remain liquid at the atmospheric pressure after passing through surface separating facilities.

under the sea

Atmosphere

Remain liquid

Drill

Principle form of petroleum

Natural gas

A mixture of hydrocarbon compounds and small quantities of various non-hydrocarbons existing in the gaseous phase or in solution with oil in natural underground reservoirs at reservoirs conditions.

NGV

CH4

Dry & Wet gas

Sweet & Sour gas

Principle form of petroleum

Natural gas

Associated gas

Non-associated gas

Principle form of petroleum

Condensate

The hydrocarbons which are in the gaseous state under reservoir conditions but become liquid either in passage up the hole or at surface due to the reduced pressure condition.

- gaseous at subsurface temperature and become liquid when cooled to surface temperature

under the sea

Gas

Atmosphere

Liquid

Drill

Principle form of petroleum

Asphalt

- Hydrocarbon which is sticky, black and highly viscous liquid or semi-solid

- Difficultly salable material, is by product of the refining process

- Difficult to dispose and relatively unprofitable

- The properties can be changed by heating it and partly oxidizing it by blowing air through it.

CONSTITUENTS

ALKANES

ISO-ALKANES

ALKENESCYCLO - ALKANES

AROMATIC

Activities in Petroleum Industries

EXPLORATION

PRODUCTION

APPRAISAL

DEVELOPMENT

Acquisition of Right

Refining & Distribution

Sequence of activities in petroleum industry.

commercial significance

install the platform to drill

bring oil/gas from subsurface to surface

TRANSPORTATION

PETROLEUM REFININGPetroleum refineries - separate crude oil

into a wide array of petroleum products through a series of physical and chemical separation techniques.

Purpose of refining- The refinery is designed to process several

different types of crude oil to produce useful petroleum product.

MAIN STEPS

CONVERSION PROCESS

TREATMENT POCESS

SEPARATION PROCESS

To split the crude oil into groups of HCUsing distillation process

Cracking or breaking down large HC molecules to smaller molecules at temperature higher than distillation

To remove impurities

(1) Separation

- split the crude oil into groups of hydrocarbon- size of different molecules - according to the number of carbon atom - the larger the molecules, the higher the boiling point of the compound

and the higher the temperature it vaporizes.- the lightest hydrocarbons boil first become vapours and are cooled, they

then condense back to liquid in reverse order; this technique known as distillation (used to separate the hydrocarbons into fractions or groups having similar boiling points).

- Inside fractionators, the column is divided at intervals by horizontal trays (perforated or valve trays).

- Valve trays - common type since can accommodate a wider range of loading

- As the vapour load in the column increases, so does the number of valves which open on each tray.

- Each tray is cooler than the one below it, thus providing a temperature gradient on which separate vapours can condense.

Distillation Process:

Heating - boiling

Vaporize – rise up through valve trays

Condense – change back to liquid – drawn off

Heater

Crude oilVapor rise up

Condense

Liquid

Liquid

CONVERSION PROCESS

a)Cracking, reforming are conversion processes used to break down large longer chain molecules into smaller ones by heating or using catalysts.

b) These processes allow refineries to break down the heavier oil fractions into other light fractions to increase the fraction of higher demand components such as gasoline, diesel fuels or whatever may be more useful at the time.

Catalyst cracking Method of operation: carried out in presence of catalyst

and H2 at high pressure. Also called as hydrocracking

Products: high-octane motor gasoline, gases used as raw material in petrochemical industry

Thermal cracking Method of operation: Using heat and pressure alone

Products: heavy fuel oils, coke, diesel oil components

Steam cracking Method of operation: Presence of steam at high temperature

and low pressure

Products: LPG and other light distillates

Reforming Method of operation: reformed by heat and pressure into

more useful molecules of the same size and boiling range, use of catalyst (platinum)

Products: motor gasoline, jet fuel

Reforming use heat, pressure and a catalyst (usually containing platinum) to bring about

chemical reactions which upgrade naphthas into high octane petrol and petrochemical feedstock.

The naphthas are HC mixtures containing many paraffins and naphthenes. It comes from thermal cracking and hydrocracking processes.

Reforming converts a portion of these compounds to isoparaffins and aromatics, which are used to blend higher octane petrol.

aromaticsnaphthenes

paraffins naphthenes

paraffins isoparaffins

Other conversion process

Alkylation refers to the chemical bonding of light molecules with isobutane to form

larger branched-chain molecules (isoparaffins) that make high octane petrol. Olefins (propylene and butylene) and isobutane are mixed with an acid

catalyst and cooled. They react to form alkylate, plus some normal butane, isobutane and propane. The resulting liquid is neutralised and separated in a series of distillation columns. Isobutane is recycled as feed and butane and propane sold as liquid petroleum gas (LPG).

Isomerisation chemical rearrangement of straight-chain HC, so that they contain branches

attached to the main chain. This is done for two reasons:they create extra isobutane feed for alkylation they improve the octane of straight-chain HC.

Isomerisation can be used to improve petrol quality by converting HC to higher octane isomers.

TREATMENT PROCESS

a) Purpose: remove impurities.b) Why?- can damage the equipment, the catalysts and

the quality of the products. c) Major impurities: SULPHUR – MERCAPTANTSd) Other impurities: nitrogen, oxygen and various metallic

compounds, all which have to be removed at a certain extent.

Hydrogen sulphide gas is also found dissolved in crude oil and is produces by the thermal decomposition of some mercaptants.

How to remove? - Remove sulphur by passing the untreated product with a stream of hydrogen through a bed of catalyst. Sulphur converted to hydrogen sulphide which the aid of chemicals, is extracted and converted into liquid or solid sulphur for sale to chemical industry.

MAJOR PRODUCTS OF OIL REFINERIES Crude oil distillation is the first stage of series of complex

petroleum processing process

Example of the product:

Liquid petroleum gas (LPG) mixture of mostly propane and butane Gasoline (petrol) liquid mixture consists most of aliphatic hydrocarbon with iso-

butane Naphtha Kerosene and related jet aircraft fuels is a combustible hydrocarbon liquid. Diesel fuel Fuel oils Lubricating oils Paraffin wax Asphalt and Tar Petroleum coke

PRODUCT OF OIL

REFINING

Light distillate

Middle distillate

Heavy distillate

residuum

Most products of oil processing are usually grouped into three categories: light distillates, middle distillates, and heavy distillates and residuum.

consists liquid petroleum gas(LPG), gasoline(petrol), motor gasoline (automobile), naphtha, jet fuel and kerosene. form such as gas oil, light and heavy domestic furnace oils, diesel fuel and distillate that used for cracking to produce more gasoline.

converted into lubricating oils, heavy oils for a variety of uses, waxes and cracking stock. includes asphalt, residue fuel oil, coke and petroleum.

Light distillate

Middle distillate

Heavy distillate

residue

Product using

petroleum

detergent

Vaseline Plastic

Recap:

What is petroleum, hydrocarbon and non-hydrocarbon?

What are the principal forms of petroleum?

List the major constituents of petroleum.State the purpose of appraisal in

petroleum industry’s activitiesIdentify the process of refiningExplain the purpose Explain the process of petroleum refiningIdentify the products of refining

NATURAL GAS

What is Natural Gas?

- A mixture of hydrocarbon compounds and small quantities of various non-hydrocarbons (e.g. nitrogen and carbon dioxide) existing in the gaseous phase or in solution with oil in natural underground reservoirs at reservoirs conditions.

Natural gas may be classified as:

i. Associated Gas: Free natural gas commonly known as gas-caps which overlies and in contact with crude oil in the reservoir

ii. Dissolved Gas: Natural gas which is in solution with crude oil in the reservoir at the reservoir condition.iii. Non-associated Gas: Free natural gas not in contact with crude

oil in the reservoir.

NATURAL GAS- terminologies

LNG = Liquefied Natural GasLPG = Liquefied Petroleum GasNGL = Natural Gas Liquids

NATURAL GAS- terminologies

NATURAL GAS PROCESSINGLNG PROCESS CHAIN:

NATURAL GAS PROCESSINGBlock Scheme - LNG Plant

EXTRACTION

ACID GAS REMOVAL

LIQUEFACTION

SCRUBBING

MERCURY REMOVAL

DEHYRATION

TRANSPORTATION

FRACTIONATION C3, C4 LPG

Hg on sorbent

Water

CO2, H2S

C2, C3 Refrigerant

C5+ Gasoline

RE-INJECTION

C2, C3, C4

Liquid

Gas

PETRONAS MLNG

NATURAL GAS PROCESSINGNatural gas is processed through the following stages.

Extraction : Natural gas is gather at the main production platform which is located offshore. It is then piped via trunk lines and enters the processing plant onshore

NATURAL GAS PROCESSINGAcid gas removal : To remove the main contaminants, carbon dioxide (CO2) together with traces of sulphur compounds.

2 methods of removal process: solvent absorption & adsorption

Solvent absorption: acid gas dissolve in the liquid followed by chemical reaction with alkali compound to produce soluble salt

Adsorption: physical adsorption on synthetic zeolites (solids)

NATURAL GAS PROCESSINGDehydration Unit : Moisture is taken down to reduce pipeline corrosion and eliminate pipe blockage caused by hydrate formation. The water dew point should be below the lowest pipeline temperature to prevent free water formation.

Methods: Physical absorption & physical adsorption

Physical Absorption process:In physical absorption process, the gas containing water is contacted with a liquid that absorbs the water vapour.

Physical Adsorption process:Physical adsorption is an equilibrium process in which the water is adsorbed onto a solid phase by means of adsorbent. In this process, the wet gas is passed through two-bed adsorbers system. One bed dries the gas while the other one, the gas goes through regeneration cycle. Regeneration involves heating the bed, removing the water and cooling.

NATURAL GAS PROCESSINGPhysical Adsorption process:

NATURAL GAS PROCESSINGMercury Removal Unit : To remove mercury in order to prevent corrosion of pipe work and equipment made from Aluminium.

Removal process: Generative and non-generative process

Nongenerative process:Utilizes sulphur sulphur-impregnated carbon for mercury removal. The mercury reacts with the sulphur to form a stable compound on the adsorbent surface. Regenerative process:Utilizes silver on molecular sieve to chemisorb mercury while providing dehydration at the same time. The silver-impregnated sieve is added to the standard molecular sieve dehydration bed, and the basic dehydration process remains unchanged. Consequently, the mercury condenses with the water on regeneration and forms a separate phase, which easily can be decanted and sold.

NATURAL GAS PROCESSINGScrubbing :To remove heavy hydrocarbons (liquid phase) by partial condensation and fed to the fractionation unit. Lighter components (gaseous phase) fed into liquefaction unit.Fractionation Unit : Pentane and heavier hydrocarbons is separated and run down as gasoline, the butanes and lighter components are re-injected into the liquefaction unit as make up.

LIQUEFACTION

SCRUBBING

MERCURY REMOVAL

TRANSPORTATION

FRACTIONATION

Hg on sorbent

RE-INJECTION

C2, C3, C4

Liquid

Gas

C3, C4 LPG

C2, C3 Refrigerant

C5+ Gasoline

NATURAL GAS PROCESSINGLiquefaction: One common method in engineering practices to produce low temperature is Joule-Thomson liquefaction cycle:

NATURAL GAS PROCESSINGLiquefaction:• The liquefaction cycles begins with natural

gas being compressed and sent through the heat exchangers and expansion valve. Upon expansion, the gas cools (approximately 47°C) if the gas is principally methane and the expansion is from 101 to 1 bar.

NATURAL GAS PROCESSINGLiquefaction:• Thus, all of the chilled low-pressure gas is

recycled through the heat exchanger for recompression. This cold low-pressure gas lowers the temperature of the high-pressure gas stream ahead of the expansion valve, which result in a lower temperature upon expansion.

NATURAL GAS PROCESSINGLiquefaction: continued:• As long as all of the gas being expanded is recycled through the

counterflow heat exchanger to cool the high-pressure gas stream, temperatures will be progressively lower upon expansion.

• The process continues until liquid is formed during the expansion from high to low pressure. The liquid formed is separated from the low-pressure gas stream in the liquid receiver.

• The liquid is withdrawn as LNG.

NATURAL GAS PROCESSINGTransportation:The LNG product is stored at temperature of -162°C and atmospheric pressure at the tank farm. The LNG is transported by three options:• Truck transport• LNG Pipelines• Marine carriers

NATURAL GAS: PRODUCT & APPLICATIONMethane (CH4)- Fuel for residential, commercial and industrial heating- Chemical feedstock, ammonia, fertilizer, methanol- For export as LNG or by pipeline as fuel or feedstock application

Ethane (C2H6)- Conversion material to ethylene (end product is plastic goods,

packaging, synthetic fibre, cloth)

Propane (C3H8) and Butane (C4H10)- Fuel for residential, commercial and industrial heating, automotive fuel- Chemical feedstock for plastic and synthetic material- Export as LPG for fuel and feedstock

Condensate (C5~C10)- Fuel for industrial heating- Chemical feedstock for plastic and synthetic material- Refinery feedstock for fuel

ENVIRONMENTAL IMPACTS

Environmental Hazards of Petroleum RefineriesRefineries-a major source of pollutant in

areaswhere they are located and are regulated by a number of environmental laws related to air,land & water.

Effect to the environment

a) Air pollution hazards -petroleum refineries are a major source of

hazardous and toxic air pollutant -major sources of criteria air pollutant -release less toxic hydrocarbon and other light

volatile fuel -health effect: -asthma -cough

b) WATER POLLUTION HAZARDS -potential major contributors to ground water

and surface water contamination -wastes are regulated under the safe drinking

water act -wastewater in refineries may be highly

contaminated during the refinery process

c) SOIL POLLUTION HAZARDS -include hazardous waste and sludges from the

treatment processes can occur from leaks

Impact of oil spills

Marine life>include the type and amount of oil and its behaviour once spilled

>effects on marine organisms Eg: birds mortality occurs

seabirds vulnerable inhabitant productivity of plankton is less

Economic - directly damage the boats and gear

used for catching or cultivating marine species

- economic loss to fishermen is

interruption to their activities