LPG

Liquefied petroleum gas

Mohamed AbdElRahman Hamed

Hussain Yaqop Behzad

Abdul Aziz Ali Suhail

Fatma Habib

introduction1

• Liquid petroleum gases were discovered in 1912 when Dr. Walter Snelling, an American scientist, realized that these gases could be changed into liquids and stored under moderate pressure. From 1912 and 1920, LP-gas uses were developed

• The first LPG cook stove was made in 1912, and the first LPG -fueled car was developed in 1913. The LPG industry began sometime shortly before World War I. At that time, a problem in the natural gas distribution process popped up.

Introduction2

• LPG is the abbreviation or short form for liquefied petroleum gas.

• LPG is a gas at atmospheric pressure and normal ambient temperatures, but it can be liquefied when moderate pressure is applied or when the temperature is sufficiently reduced.

Introduction3

• Normally, the gas is stored in liquid form under pressure in a steel container, cylinder or tank.

• When you start using LPG, some of the pressure in the container is released. Some of the liquid LPG then boils to produce vapor.

Introduction4

• LPG is highly flammable and must therefore be stored away from sources of ignition and in a well-ventilated area, so that any leak can disperse safely.

• Although LPG is non-toxic, its abuse –(like that of solvents)– is highly dangerous

What is LPG?1

• LPG is the generic name for commercial propane and commercial butane. These are hydrocarbon products produced by the oil and gas industries. Commercial Propane predominantly consists of hydrocarbons containing three carbon atoms, mainly propane (C3H8).

What is LPG?2

• Commercial Butane predominantly consists of hydrocarbons containing four carbon atoms, mainly n- and iso - butanes (C4H10).

What is LPG?3

• They have the special property of becoming liquid at atmospheric temperature if moderately compressed, and reverting to gases when the pressure is sufficiently reduced. Advantage is taken of this property to transport and store these products in the liquid state, in which they are roughly 250 times as dense as they are when gases.

• Butane is usually supplied to customers in cylinders. Propane can be supplied in cylinders or in bulk for storage in tanks at the customers premises.

• IF A CYLINDER IS NO LONGER NEEDED IT SHOULD BE RETURNED TO A LOCAL DEALER.

Application1

• IN THE HOME– Space-heating – Central heating– Air-conditioning – Hot-water supply – Barbeques– Cooking – Patio Heaters

Application2

• AT WORK – Gas and chemicals– Ferrous and non-ferrous metals– Engineering equipment and ships– Heavy clay and ceramics– Glass– Food and drink– Mechanical handling equipment (FLTs)– Textiles, leather and clothing– Paper and print

Why is it called Liquefied Petroleum Gas?

• This is because these gases can be liquefied at normal temperature by application of a moderate pressure increase, or at normal pressure by application of cooling using refrigeration.

Where does LPG come from?

• LPG comes from two sources. It occurs naturally in oil and gas fields and is separated from the other components during the extraction process from the oil or gas field. LPG is also one of the by-products of the oil refining process.

WHAT IS LNG?

• When natural gas is cooled to a temperature of approximately -260°F at atmospheric pressure it condenses to a liquid called liquefied natural gas (LNG). One volume of this liquid takes up about 1/600th the volume of natural gas at a stove burner tip. LNG weighs less than one-half that of water, actually about 45% as much. LNG is odorless, colorless, non-corrosive, and non-toxic. When vaporized it burns only in concentrations of 5% to 15% when mixed with air. Neither LNG, nor its vapor, can explode in an unconfined environment.

COMPOSITION

• Natural gas is composed primarily of methane (typically, at least 90%), but may also contain ethane, propane and heavier hydrocarbons. Small quantities of nitrogen, oxygen, carbon dioxide, sulfur compounds, and water may also be found in "pipeline" natural gas. The liquefaction process removes the oxygen, carbon dioxide, sulfur compounds, and water. The process can also be designed to purify the LNG to almost 100% methane.

WHAT IS CNG?

• Compressed natural gas (CNG) is natural gas pressurized and stored in welding bottle-like tanks at pressures up to 3,600 psig. Typically, it is same composition of the local "pipeline" gas, with some of the water removed. CNG and LNG are both delivered to the engines as low pressure vapor (ounces to 300 psig). CNG is often misrepresented as the only form natural gas can be used as vehicle fuel. LNG can be used to make CNG. This process requires much less capital intensive equipment and about 15% of the operating and maintenance costs.

What are the advantages of LPG?1

• Because if its relatively fewer components, it is easy to achieve the correct fuel to air mix ratio that allows the complete combustion of the product. This gives LPG its clean burning characteristics.

• Both Propane and Butane are easily liquefied and stored in pressure containers. These properties make the fuel highly portable, and hence, can be easily transported in cylinders or tanks to end-users.

• LPG is a good substitute for petrol in spark ignition engines. Its clean burning properties, in a properly tuned engine, give reduced exhaust emissions, extended lubricant and spark plug life.

What are the advantages of LPG?2

• As a replacement for aerosol propellants and refrigerants, LPG provides alternatives to fluorocarbons which are known to cause deterioration of the earth's ozone layer.

• The clean burning properties and portability of LPG provide a substitute for indigenous fuels such as wood, coal, and other organic matter. This provides a solution to de-forestation and the reduction of particulate matter in the atmosphere (haze), caused by burning the indigenous fuels.

What are the Properties of LPG?

• Colorless.• Odorless. (It is normal to odorize LPG by adding

an odorant prior to supply to the user, to aid the detection of any leaks).

• Flammable.• Heavier than air.• Approximately half the weight of water.• Non toxic but can cause asphyxiation.• LPG expands upon release and 1 litre of liquid

will form approximately 250 litres of vapour.

Properties of LPG

LPG Composition ( % by volume ) as Automotive Fuel in Europe

• Country Propane Butane• Austria 50 50• Belgium 50 50• Denmark 50 50• France 35 65• Greece 20 80• Ireland 100 ---• Italy 25 75• Netherlands 50 50• Spain 30 70• Sweden 95 05• UK 100 ---• Germany 90 10

Process description and discussion

• A gas stream coming from East Kuwait oilfields that contains the following composition is proposed to be treated to reduce the amount of the sour gas:

• The gas stream was entering at 300C and 6895 kpa and with flow of 1000 Kgmole/h.

Component Composition

Nitrogen 0.001901

Carbon dioxide 0.077625

Hydrogen sulfide 0.025008

Methane 0.764945

Ethane 0.050416

Propane 0.017406

Iso-Butane 0.006402

n-Butane 0.007202

Iso-Pentane 0.004301

n-Pentane 0.003701

n-Hexane 0.006602

n-Heptane 0.03081

Water 0.003681

Process Description1

• The gas stream was fed to a separator to remove any liquids in it. Where the vapor fraction in the feed was 92% and it was having liquid about 8%

Process Description2

• Then the gas stream out of the separator (V1) was fed to the absorber to clean it from sour gases using the solvent that contained 90% water and 10% Diethyl-amine. The inlet vapor (V1) flow was 923.5 Kgmole/hr and the solvent (S) amount used for cleaning was 2001.4 Kgmole/hr. The fraction of hydrogen sulfide in the outlet gas stream (abs V) was below 0.00001 which was the first objective.

Process Description3

• The outlet liquid stream from the absorber (abs L) is rich in Diethyl-amine so it will be generated.– First its pressure needs to be lowered to 620 KPa by using a throttling

valve.

– Then its gases content will be separated by a second separator.

Process Description4

– The liquid stream out of the second separator will be heated to 95 C and its pressure will be lowered again to 205 Kpa for this case another valve will be used and a heat exchanger using the bottom outlet stream from the distillation tower as a heating stream.

– This was to make the distillation process much easier.

Process Description5

• The distillation process took place in a ten trays distillation tower. The feed (toDist) was in tray number five

• The aim of this distillation is to achieve the larges possible recovery of Diethyl-amine which was easy because the feed contained hydrogen sulfide, carbon dioxide, water and Diethyl-amine it is possible with a mixture like this to get 100% recovery of Diethyl-amine.

Process Description6

• The top stream (D) contains all of hydrogen sulfide from the feed, most of carbon dioxide, some water and no Diethyl-amine

• The bottom stream (W) contains all of the Diethyl-amine and it is at high temperature so it was the best one to heat the feed of the distillation tower.

• After losing some energy the stream was pressurized using a pump and cooled using a cooler.

• The stream is then mixed with a make up stream that contains only water to recover the water loss in different units like the second separator and the distillation tower.

LPG Production line1

• The pressure gas coming out of the absorber was reduced using a valve from 6895 KPa to 4137 KPa and the temperature also reduced from 30.5oC to 15.0oC using a heat exchanger and the cold gas stream containing methane and ethane from the distillation tower

LPG Production line2

• The cold stream was fed into a separation vessel to remove all liquids contents

LPG Production line3

• The vapor stream was fed into the bottom of a 10 trays distillation tower to separate the methane and ethane from the other content of the sweet gas.

LPG Production line4

• The reflux ratio in the tower was 3• The recovery of methane and ethane was almost 100 %• The recovery of the other gases was 100%

LPG Production line5

• The bottom stream out of the first tower was fed into a second distillation tower from its bottom to finally separate the LPG

LPG Production line6

• The reflux ratio was 5• The recovery of propane was 99%• The recovery of iso-butane was 90%• The recovery of normal butane was 50%