Srimonto Roy Petroleum and Mining Engineering

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Acknowledgement
At first we are grateful to our Almighty Creator who is most beneficent and merciful. We would
like to thank our head of our department, DR. H M Zakir Hossain for granting us permission to
perform this plant visit. We express our deepest and profound respect to our teachers Md.
Moklesur Rahman and Farzana Yeasmin Nipa. We are indebted to them for helping us by
providing the necessary guidance, encouragement, valuable suggestions, strong inspection and
advice to perform the work successfully. We give special thanks to lecturer of the Kailashtilla
gas field for helping us on our site visit and completing it without any obstacles. We also want to
thank all the people of Kailashtilla Gas Field Ltd. for their assistance, encouragement and
support.

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CHAPTER-1:
Introduction

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1.1 Study area Background
Mineral Resources mineral reserves plus all other deposits that may eventually become available
- either known deposits that are not economically or technologically recoverable at present, or
unknown deposits, rich or lean, that may be inferred to exist but have not yet been discovered.
Geologically, Bangladesh occupies a greater part of the bengal basin and the country is covered
by Tertiary folded sedimentary rocks (12%) in the north, north eastern and eastern parts; uplifted
Pleistocene residuum (8%) in the north western, mid northern and eastern parts; and Holocene
deposits (80%) consisting of unconsolidated sand, silt and clay.
Figure -1:Bangladesh maps.

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1.2 Plant Definition & Objectives
A natural gas processing plant is a facility designed to process raw natural gas by separating
impurities and various non-methane hydrocarbons and fluids to produce what is known as
pipeline quality dry natural gas.
The objective of the report is to-
 1.Design a natural gas processing plant located at Kailashtilla, Sylhet in Bangladesh.
 2.Sylhet 1.4 gas Blowout.
 3.Tamabil Port.
1.3 Definition of Natural Gas
Natural gas is a mixture of Methane, ethane, propane, butane, pentane, carbon dioxide, Nitrogen
etc. is the most important fuel belonging to this class & is found mainly in the vicinity of coal
mines or oil fields. The natural gas is also found associated with petroleum in Nature. It is not
only used as fuel or domestic or industrial purposes but also used as a chemical raw material for
various syntheses. Most of the natural gas used as fuel is derived from oil fields. However
sometimes the gas evaporated from the oil & diffused through rocks is trapped by impervious
dome shaped structure which may be far off from the original oil deposit. This constitutes a gas
field which may be under high pressure. Due to earth movement or pressure it may suddenly
escape out through fissure. This may result in ignition on its emergence to the atmosphere,
because of the static electricity produced by the rushing gas or because of increased temperatures
caused by friction. This gas is collected from the mine by drilling well & after some processing it
reaches to the consumers.
The global use of natural gas is growing rapidly. This is primarily attributed to the environmental
advantages it enjoys over other fossil fuels such as oil and coal. There is worldwide drive
towards increasing the utilization of natural gas and the need to minimize energy consumption
and increase profit associated with the process. These objectives can be achieved by reducing
time required to get products to market, increasing the quantity and quality of product produced
and designing plants for an optimum performance along their life cycle.
In Bangladesh this resource is controlled by the Bangladesh Oil gas & mineral Corporation
(PetroBangla). It has different departments to control different sections.

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1.4 Classification of Natural Gas
The natural gas derived from wells are divided into three types, according to consisting of
different kinds of Hydrocarbon.
1. Dry Gas: If the lower hydrocarbons like methane ethane etc. are present at large amount &
small amount of water in well gas is called dry gas.
2. Wet Gas: If higher hydrocarbons are present with natural gas then it is called wet gas. It is also
called “marsh gas”.
1.5 Key Definitions
Methane:
Methane is the predominant component of natural gas typically forming of 70% -99% of bulk
gas. It is colorless, odorless flammable gas. It is chemically inactive sparingly soluble in water &
is lighter than air.
Condensate:
It refers to the portion which condenses and separates out from NG as liquids when the gas is
produced at the surface. This liquid is composed of heavier hydrocarbon that exists as vapor
dissolved in NG in underground pressure temperature condition but turned to liquid at the
surface wellhead condition. Condensate is a valuable product & is processed to use commercially
as fuel.
Natural Gas Liquids (NGL):
NGL refers to a mixture of all hydrocarbons except methane which can be extracted by
compression and cooling in separator. After extraction NGL is distilled to be separated into
ethane, propane, butane & natural gasoline.
Liquefied Petroleum Gas (LPG):
LPG refers to mixture of essentially propane and butane which is extracted from wet natural gas.
LPG is also available during of crude oil. It is used as fuel to run automobiles.
Liquefied Natural Gas (LNG):
LNG refers to liquid form of natural gas that is produced by special liquefaction process in a
plant surface. LNG is suitable for transportation.

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Compressed Natural Gas (CNG):
It refers to the NG made available in compressed form for the use as fuel in vehicles. Usually
NG is compressed to 300 pounds per square inch gauge in refining station and put in cylinder for
CNG run vehicles cooling the gas to 160oC.
Hard Rock
Hard rock is a loosely defined subgenre of rock music that began in the mid-1960s, with the
garage, psychedelic and blues rock movements. It is typified by a heavy use of aggressive vocals,
distorted electric guitars, bass guitar, drums, and often accompanied with keyboards.
Limestone
Limestone is a carbonate sedimentary rock that is often composed of the skeletal fragments of
marine organisms such as coral, foraminifera, and molluscs. Its major materials are the minerals
calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). A closely
related rock is dolomite, which contains a high percentage of the mineral dolomite,
CaMg(CO3)2. In fact, in old USGS publications, dolomite was referred to as magnesian
limestone, a term now reserved for magnesium-deficient dolomites or magnesium-rich
limestones.

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CHAPTER-02:
Kailashtila Silicagel
Plant

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2.1 Kailashtila silicagel plant
Kailashtila Field was discovered by Pakistan Shell Oil Company (PSOC) in 1961. A gas well
(Kailashtila-1) was completed in June 1983 with the initial production of 30 MMCFD. Later,
three more wells namely KTL-2 (1988), KTL-3 (1988) & KTL-4 (19996) were drilled in this
field. Gas of Kailashtila has a very high condensate ratio in comparison to Haripur Gas Field.
The well KTL-5 added to the field with a production capacity of 15 MMSCF per day with a
condensate ratio 40 bbl/MMCF. Another well KTL-6 started producing from 8th August 2007.
Production of KTL-5 ceased on 22 October 2009 due to excessive water production and
reduction of well head pressure. The well KTL-7 added to the field with a production capacity of
6 MMSCFD. The production ceased from KTL-7 on 01-11-2016 due to reduction of well head
pressure.
A 30 MMSCFD capacity solid desiccant (silicagel) plant started operation since 1983 at the
location of KTL-1. Presently gas production from wells KTL-1 and KTL-5 is being processed
through this silicagel plant.
Silica gel
Silica gel is silicon dioxide (SiO2), manufactured as small round beads with a large pore surface
area onto which the water, contained in the vapor phase in the gas, is adsorbed by the desiccant
at relatively low temperatures. The affinity for water is temperature dependent, and the affinity
for water is broken at high temperatures, such as 390°F. It is necessary to avoid liquid water
droplets from contacting the silica gel, as liquid water damages the desiccant. Thus, it is
important to have effective gas/liquid separation ahead of a dry desiccant unit.
2.2 Design Basis
Natural gas is considered 'dry' when it is almost pure methane, having had most of the other
commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural
gas is 'wet'. Raw natural gas co mes primarily from any one of three types of wells: crude oil
wells, gas wells, and condensate wells
Crude oil wells raw natural gas that comes from crude oil wells is called associated gas. This gas
can exist separate from the crude oil in the underground formation, or dissolved in the crude oil.
Condensate produced from oil wells is often referred to as lease condensate.
Dry gas wells these wells typically produce only raw natural gas that does not contain any
hydrocarbon liquids. Such gas is c alled non associated gas. Condensate from dry gas is extracted
at gas processing plants and, hence, is often referred to as plant condensate.

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Condensate wells these wells produce raw natural gas along with natural gas liquid. Such gas is
also called associ ated gas and often referred to as wet gas.
Figure-2: Gas well
2.3 Process Description
1.Oil and Condensate Removal
In order to process and transport associated dissolved natural gas, it must be separated from the
oil in which it is dissolved. This separation of natural gas from oil is most often done using
equipment installed at or near the wellhead.
The actual process used to separate oil from natural gas, as well as the equipment that is used,
can vary widely. Although dry pipeline quality natural gas is virtually identical across different
geographic areas, raw natural gas from different regions may have different compositions and
separation requirements. In many instances, natural gas is dissolved in oil underground primarily
due to the pressure that the formation is under. When this natural gas and oil is produced, it is
possible that it will separate on its own, simply due to decreased pressure; much like opening a
can of soda pop allows the release of dissolved carbon dioxide. In these cases, separation of oil
and gas is relatively easy, and the two hydrocarbons are sent separate ways for further
processing. The most basic type of separator is known as a conventional separator. It consists of
a simple closed tank, where the force of gravity serves to separate the heavier liquids like oil, and
the lighter gases, like natural gas.
Gas well

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In certain instances, however, specialized equipment is necessary to separate oil and natural gas.
An example of this type of equipment is the Low-Temperature Separator (LTX). This is most
often used for wells producing high pressure gas along with light crude oil or condensate. These
separators use pressure differentials to cool the wet natural gas and separate the oil and
condensate. Wet gas enters the separator, being cooled slightly by a heat exchanger. The gas then
travels through a high pressure liquid „knockout‟, which serves to remove any liquids into a low-
temperature separator. The gas then flows into this low-temperature separator through a choke
mechanism, which expands the gas as it enters the separator. This rapid expansion of the gas
allows for the lowering of the temperature in the separator. After liquid removal, the dry gas then
travels back through the heat exchanger and is warmed by the incoming wet gas. By varying the
pressure of the gas in various sections of the separator, it is possible to vary the temperature,
which causes the oil and some water to be condensed out of the wet gas stream. This basic
pressure-temperature relationship can work in reverse as well, to extract gas from a liquid oil
stream.
2.Water Removal
In addition to separating oil and some condensate from the wet gas stream, it is necessary to
remove most of the associated water. Most of the liquid, free water associated with extracted
natural gas is removed by simple separation methods at or near the wellhead. However, the
removal of the water vapor that exists in solution in natural gas requires a more complex
treatment. This treatment consists of „dehydrating‟ the natural gas, which usually involves one of
two processes: either absorption, or adsorption.
Absorption occurs when the water vapor is taken out by a dehydrating agent. Adsorption occurs
when the water vapor is condensed and collected on the surface.
3.Solid-Desiccant Dehydration
Solid-desiccant dehydration is the primary form of dehydrating natural gas using adsorption, and
usually consists of two or more adsorption towers, which are filled with a solid desiccant.
Typical desiccants include activated alumina or a granular silica gel material. Wet natural gas is
passed through these towers, from top to bottom. As the wet gas passes around the particles of
desiccant material, water is retained on the surface of these desiccant particles. Passing through
the entire desiccant bed, almost all of the water is adsorbed onto the desiccant material, leaving
the dry gas to exit the bottom of the tower.

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Figure-03: Dehydration.
Solid-desiccant dehydrators are typically more effective than glycol dehydrators, and are usually
installed as a type of straddle system along natural gas pipelines. These types of dehydration
systems are best suited for large volumes of gas under very high pressure, and are thus usually
located on a pipeline downstream of a compressor station. Two or more towers are required due
to the fact that after a certain period of use, the desiccant in a particular tower becomes saturated
with water. To „regenerate‟ the desiccant, a high-temperature heater is used to heat gas to a very
high temperature. Passing this heated gas through a saturated desiccant bed vaporizes the water
in the desiccant tower, leaving it dry and allowing for further natural gas dehydration.
3.1 The dynamics of adsorption bed
Fig. 2 illustrates the basic behavior of an adsorbent bed in gas dehydration service. During
normal operation in the drying (adsorbing) cycle, three separate zones exist in the bed:
(i)Equilibrium zone
In the equilibrium zone, the desiccant is saturated with water; it has reached its equilibrium water
capacity based on inlet gas conditions and has no further capacity to adsorb water.
(ii)Mass transfer zone (MTZ)
Virtually all of the mass transfer takes place in the MTZ, a concentration gradient exists across
the MTZ.
Dehydration

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(iii)Active zone
In the active zone the desiccant has its full capacity for water vapor removal and contains only
that amount of residual water left from the regeneration cycle. When the leading edge of the
MTZ reaches the end of the bed, breakthrough occurs.
Figure-04 : Three zones of adsorption.
4.Fractionation
The particular fractionators are used in the following order:
 Deethanizer – this step separates the ethane from the NGL stream.
 Depropanizer – the next step separates the propane.
 Debutanizer – this step boils off the butanes, leaving the pentanes and heavier
hydrocarbons in the NGL stream.
 Butane Splitter or Deisobutanizer – this step separates the iso and normal butanes.

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Figure-:Fractionation unit.
Fractionation unit

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CHAPTER-03:
Kailashtilla
Molecular Sieve
Turbo Expander
(MSTE).

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3.1 Kailashtilla Molecular Sieve Turbo Expander Plant
A 90 million cubic feet/day capacity Molecular Sieve Turbo Expander (MSTE) Plant situated at
the location of KTL-2 was installed in 1992-95 by Press Construction (UK) Ltd. MSTE Plant
went into commercial operation in September 1995. This plant, first of its kind in Bangladesh,
employs modern cryogenic mechanism to recover liquefiable hydrocarbons. The advantage of
employing this mechanism is that an additional amount of Natural Gas liquids (NGL) in the
range of 8-10 bbl/MMSCF is being recovered which would have otherwise remained
unrecovered had conventional plant been used.
Figure:Plant Layout.
The present average condensate/NGL recovery from the MSTE Plant is around 18 bbl/MMSCF.
The gas delivered from the MSTE Plant is fed through the 24 inch diameter National Gas Grid
Line and JGTDSL. NGL recovered at the MSTE Plant is supplied as feed to LPG Plant of
RPGCL to fractionate the NGL into LPG and MS (Motor Spirit). LPG is subsequently marketed
by BPC in LPG Bottle/Cylinder. The condensate is Supplied as a feed to distillation unit of
Kailashtilla Field and remaining condensate is sold to private refineries through tank lorries.
Molecular sieves
Molecular sieves are usually installed in applications in which very low residual water content is
required, such as ahead of a low temperature hydrocarbon extraction process. Molecular sieves
are suitable for drying very sour natural gas that also contains aromatic compounds.[1] The
heavier hydrocarbons might be difficult to remove from the silica gel during the regeneration
step.

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3.2 Necessity of Natural Gas Processing
 Removal of unwanted and corrosive components (water, sludge, dust, H2S, CO2 etc.) to
meet the pipeline quality gas.
 Recovery of the valuable components(liquid hydrocarbons).
 Maintaining the delivery pressure and temperature .
3.3 Process Description
 Firstly raw natural gas is collected from the well heads and then sent to gas processing
plant also named.
 Molecular sieves are used for gas dehydration
 Turbo expander/ J-T valve (cryogenic process) used for natural gas liquid (NGL)
recovery.
3.4 Molecular Sieve – Turbo Expander (MSTE) Plant
In Kailashtilla gas field raw natural gas is collected from the well heads which is a mixture of
natural gas, water, natural gas condensate etc. In natural gas process plants these different
components are separated and pipeline quality natural gas is extracted. In this plant Molecular
Sieves are used for gas dehydration and Cryogenic process (Turbo expander / J-T Valve) is
applied for Natural Gas Liquid (NGL) recovery. The process units of the plant are described
below:
1. Inlet heater:
It is a double pipe type heat exchanger. Gas from the wells is fed to three separate inlet heaters to
raise the temperature above 26°C. It is done to prevent hydrate formation when inlet gas pressure
is reduced to 88bar from 150bar. Gas is passed through the tubes and hot oil (Therminol-6, 6) on
the shell side.
2. Inlet separator / Three Phase Separator:
Gases from three inlet heaters are fed to three corresponding inlet separator. In these separators
components are separated by specific gravity and a pressure of 88bar is maintained. Feed is
separated into Gas, water and Condensate. Water level in the separator is maintained at a certain
level and excess is drained, gas is fed to inlet filter and condensate is charged into Stabilizer at 7
bar and 20°C.

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PFD Diagram:

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PFD Diagram: (with utility)

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3. Inlet Filter Separator:
Feed gas from the three-phase separator is further filtered here to protect the molecular sieve in
the dehydrator tower. There are two units, one is always on duty and another is spare. This unit
consists of filter area with replaceable filter element and a vent type mist extractor.
4. Molecular Sieve Type dehydrator:
There are different types of gas dehydrator based on desiccants such as silica-gel type, TEG
(Glycol) type, Molecular sieve type etc. In this plant Molecular sieves are used in dehydration of
gas stream. Two dehydrators are used; one is on duty and another in regeneration for time cycle
of 8 hours.
Molecular sieve has porous cavities to entrap moistures. Feed gas at 88bar pressure and 29°C are
fed to one online dehydrator from the top in a down flow pattern for 8 hours. When desiccants
are exhausted the unit is turned into regeneration cycle and the other one is made online.
Regeneration of Molecular sieves:
Regeneration is done by passing hot gas through the bed; this gas is fed from the bypass of the
residue gas. The steps in regeneration are:
 Depressurization:
First the flow of gas to the tower to be regenerated is cut off by closing the valve and
depressurized slowly from 88bar to 32bar over a time period of 30 minutes to avoid high gas
velocity that can damage the bed. The residue gas from expander-compressor or J-T valve is
passed through a heat exchanger and gas temperature is raised to 276°C. The hot gas is then
passed through the bed for 4 hours, bed temperature become 180°C and water in the molecular
sieves are vaporized and flow with hot gas.
To make the bed ready for dehydration residue gas is passed through a bypass line instead of the
heat exchanger and then passed through the bed for 3 hours. Bed temperature is decreased to
42°C.
 Pressurization:
The tower is pressured back to 88bar from 32bar in a period of 30min. Then the inlet gas is
bypassed to this tower for dehydration and the other one starts regeneration.
5. Regeneration gas heater:
It is a shell & tube type heat exchanger. Hot oil at 276°C passes through the tube side and gas is
passed through the shell side and gas is heated for using in regeneration of bed.

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6. Regeneration gas cooler:
This is an air cooled heat exchanger. It is used to condense the water and hydrocarbon vapor
produced during the regeneration heat cycle. The outlet temperature is 16 to 49°C.
7. Regeneration Gas scrubber:
In this unit gas is passed to separate gas and any liquid contents. Gas leaves this vessel at the top
and passes through a mesh screen so that any residue is collected.
8. Dust Filter:
Dusts maybe present in the gas and also can be the cracked particles of molecular sieves. Dusts
are removed by passing the gas stream through a dust filter. Water molecules present after
dehydration are also entrapped here. Outlet stream of this unit is then passed to the Gas to gas
heat exchanger (97%) and De-ethanizer feed heater (3%).
9. Gas to Gas heat exchanger:
It is a shell and tube type heat exchanger which is used to cool the gas. The cooling gas is the gas
stream from the top of the De-ethanizer column which is at a temperature of - 47°C as a result of
going through the cryogenic process. The hot stream is at 29°C that is to be cooled down.
10. Cold separator:
In gas-gas heat exchanger the inlet gas is cooled down to -18°C, as a result liquid is formed by
condensation. Cold separator extracts this condensed liquid.
Inlet gas then flows through the 3 expanders or their bypass J-T (Joule Thomson) valves. Then
flows to the expander separator. Liquid formed in this unit also flows to the expander separator.
11. Turbo expander:
A turbo expander, also referred to as an expansion turbine, is a centrifugal or axial flow turbine
through which a high pressure gas is expanded to produce work that is often used to drive a
compressor. Turbo expanders are very widely used as sources of refrigeration in industrial
processes such as the extraction of ethane and natural gas liquids (NGLs) from natural gas.
Inlet gas from the cold separator flows through the 3 expanders at 88bar. The expansion of the
gas releases energy and provides work. As a result gas stream is cooled down to - °C and as the
temperatures of the gases drop below the dew point, they condense out as liquid and higher
hydrocarbon such as propane, butane is recovered as NGL.

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12. J-T (Joule-Thomson) valve:
It is an alternative to the turbo expander, also when turbo expander is overloaded JT valve is
used to expand the excess gas stream.
The use of turbo expanders, however, does not eliminate the need for the Joule Thompson valve.
This is typically referred to as the expander bypass valve but operates under the Joule Thompson
effect. The valve is used to enable a more efficient startup and shutdown of the turbo expander. It
is also used to continue the process when the expander goes offline or if flow increases beyond
the full speed capacity of the turbo expander.
Inlet gas flows through the 3 expanders or their bypass J-T (Joule Thomson) valves. Then it
flows to the expander separator.
13. Expander / Cold separator:
It is designed to separate the NGL liquid from the gas stream which is coming from turbo
expander / JT valve. This separator has to inlet, one from cold separator bottom and another from
expander outlet. The gas from this unit is passed through a mist extractor to recover residual
NGL. Separated NGL from this unit is then fed to the De-ethanaizer.
14. De-ethanizer feed heater:
This heat exchanger is used for pre heating the De-ethanizer feed. Process gas from dust filter is
used as heating media. The feed is heated so that ethane recovery becomes easier.
15. De-ethanizer:
It is a fractionation column. The purpose of de-ethanizer is to remove ethane and trace amount of
methane from NGL that contains propane, butane etc. It consists of number of trays with bubble
caps. Lighter components are stripped from NGL and these gases leave the tower at the top. De
ethanized NGL is then stored in NGL storage tanks.
16. De ethanizer Reboiler:
It is a kettle type reboiler that supplies sufficient heat to the bottom liquid to produce enough
vapors to strip the lighter components from NGL feed. Hot oil flows through tube bundle. The
reboiler shell has spillover internal weir that keep the tube bundle submerged in liquid.
17. Residue Gas Compressor:
There are five gas compressors which are identical and separate self-contained packaged unit.
Each unit has lube oil and cooling systems. These compressors work in parallel. Gas from
expander compressor common discharge header in cryogenic section is fed to these compressors
after compression gas pressure is increased to 55 bar and fed to the pipeline.

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18. Gas Cooler:
Temperature of the gas raise as the pressure increased. So gas needs to be cooled. Compressed
gas cooled at 300C by a gas cool and fed to the pipeline.
Final Gas pressure and temperature in the pipeline is 55 bar at 300C.
3.5 Liquid Hydrocarbon (Condensate) Processing
1. Liquid Stabilizer:
The stabilizer with 16 trays to handle hydrocarbon Liquid that drops out in the three inlet
separators. Liquid from the inlet separator is flashed to 12.1bar and is feed into the top of the
stabilizer. The stabilizer operates at 200C on the top tray and 1800C on the bottom tray. The
stabilizer reboiler outlet temperature is controlled at 2120C at 7 bar. The liquid is cooled to 350C
and then pumped to NGL surge drum. The vapor product is fed to fuel gas system at a rate of
500 m3/hr. 97% of the ethane & 62% propane plus heavier components exit the bottom as a
stabilized NGL product. In this process all of the N2 & CO2 from the feed stream is removed.
The total liquid stream from tray number 8 is routed through the separator where the water settles
out of the hydrocarbon. The hydrocarbon is then returned to the stabilizer on to tray no 9.
The tower feed is saturated with water; therefore a water separator is required to remove the
undesired water. The separator is fed from a draw-off tray below tray-8 & returns hydrocarbon
condensate must flow through the mesh pad mater molecules are coalesced to from larger
droplets of water. In the separator section water is separated from the hydrocarbon condensate &
accumulated in the separated boot. Water accumulated in the separated boot must be drained
manually at regular intervals to prevent flooding in the stabilizer, which may reduce the
efficiency of the stabilizer.
Heat is added to the bottom of the tower by the stabilizer reboiler. The reboiler is a kettle type
with hot oil circulated through the tube bundle. The hot oil flow is temperature controlled to
maintain a constant tower bottom temperature. The reboiler shell is equipped with a spill-over
weir which ensures that the tube bundle is completely submerged in liquids at all times. The weir
forms a reservoir on the down streamside where NGL product is collected. The excess NGL
product is level controlled from the reservoir section through the stabilizer product cooler.
2. Stabilizer Product Cooler:
The 1750C NGL product from the stabilizer is cooled to 300C by to identical forced draft air-
cooled exchanger. One air cooler is spare & appropriate isolating valves are provided. Each air
cooler has three fans driven by 1.6KW electric motors. After cooling, NGL product is pumped to
the surge drum.

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CHAPTER-04:
Kailashtilla Gas Field
Safety and Hazards

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4.1 Plant Safety Issues
Safety is a term consists of some precautionary measures that are observed by the people at the
time of performing a job inside the factory with the help of some machines & equipments.
The ultimate aim of safety is the complete prevention of personal injury, loss of life &
destruction of property. Effective plant safety & fire protection are essential for every phase of
operation and maintenance of equipment& machines. Equipments & other individual items must
be examined time to time for normal service and also for emergency demand. All buildings,
workshops, installation & equipments must be furnished and maintained so as to protect the
workers against accidents & professional diseases.
4.2 Hazards in Plant
Incidents occur in natural gas processing due to
Properties of medium handled
-Toxic, Reactive, Flammable, Explosive
Process upset
-Temperature, Pressure, Level, Composition etc.
Safety hazards associated with gas extraction activities are-
1. Vehicle Collision
2. Struck-By/Caught-In/Caught-Between
3. Explosions And Fire
4. Falls
5. Chemical exposure
6. Confined Spaces
7. Ergonomic Hazard
8. High Pressure lines And Equipment
9. Electrical And Other Hazardous Energy
10. Machine Hazard
11. Gas Flare

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1. Vehicle Collisions
Workers and equipment are required to be transported to and from well sites. Wells are often
located in remote areas, and require traveling long distances to get to the sites. Highway vehicle
crashes are the leading cause of gas extraction worker fatalities. One of the main reasons for
these reckless accidents has been carelessness and less alertness or exhausted drivers. Many a
time‟s trucks were found to be in disrepair and in a bad condition.
OSHA's Motor Vehicle Safety and NIOSH's provide Prevention Strategies for Employers which
give sufficient guidance and safety regulations to prevent vehicle collisions for oil rig workers.
2. Struck-By/Caught-In/Caught-Between
Three of every five on-site fatalities in the oil and gas extraction industry are the result of struck-
by/caught -in/caught-between hazards. Workers might be exposed to struck-by/caught-in/caught-
between hazards from multiple sources, including moving vehicles or equipment, falling
equipment, and high-pressure lines. The following OSHA and NIOSH documents provide
guidance on recognizing and controlling these hazards.( Crane, Derrick, and Hoist Safety,
Struck-By Guidelines on the Stability of Well Servicing Derricks).
Figure:PPE

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Relevant OSHA standards applicable to these hazards include:
 Eye and face protection 1910.133
 Head protection 1910.135
 Foot protection 1910.136
 Hand protection 1910.138
 Handling materials - General 1910.176
 Powered industrial trucks 1910.178 App A
 Crawler locomotive and truck cranes 1910.180
 Slings 1910.184
 Machinery and machine guarding 1910 Subpart O
 General requirements for all machines 1910.212
 Mechanical power-transmission apparatus 1910.219
3. Explosions and Fires
Oil and gas rigs house a lot of highly combustible chemicals and gas, which means there is
always a chance of a fire breaking out or explosions. Most of the times these occur without the
slightest warning and so are difficult to prevent. You need to be ready with all possible
preventive measures to face such hazards.
A detailed firefighting plant:
 need to have equipment, extinguishers and suppression agents ready in case of an
emergency
 Most of the accident prone areas like gas chambers, oil tanks and electricity rooms are
under continuous threat of fire and explosion; it is important that all the machinery and
equipment susceptible to fire should be inspected on a regular basis.
 Placing adequate amount of extinguishers and safety equipment in and around such
places.
 Offering proper safety training to the employees working in such hazardous areas.
 Regular inspection and maintenance of such places and equipment can reduce the risks of
such hazards.

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Figure :Fire Safety Appliances
Fire Hydrant
A fire hydrant is a connection point by which firefighters can tap from a water supply. It is a
component of active fire protection. The user attaches a hose to the fire hydrant, then opens a
valve on the hydrant to provide a powerful flow of water.
4. Falls
Workers might be required to access platforms and equipment located high above the ground.
OSHA requires fall protection to prevent falls from the mast, drilling platform, and other
elevated equipment.
 It is important that the floor is kept clear of unnecessary tools, ropes or cords. Also make
it a point to clean oil or chemical spills immediately.
 Making use of slip resistant and waterproof boots to reduce slips and trips.
5. Confined Space
Workers are often required to enter confined spaces such as petroleum and other storage tanks,
mud pits, reserve pits and other excavated areas, sand storage containers, and other confined
spaces around a wellhead. Safety hazards associated with confined space include ignition of
flammable vapors or gases. Health hazards include asphyxiation and exposure to hazardous
chemicals. Confined spaces that contain or have the potential to contain a serious atmospheric

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hazard must be classified as permit-required confined spaces, tested prior to entry, and
continuously monitored.
 Avoid entering confined spaces, e.g. by doing the work from outside.
 If entry to a confined space is unavoidable, develop and implement a safe system of
work.
 And devise an appropriate emergency plan before the work start.
6. Chemical Exposure
Most of the gas rigs release high concentrations of H2S (Hydrogen sulfide). Pipeline operator
faces maximum risks caused by dangerous levels of H2S. It can cause paralysis, leukemia and
other cancers or even death. Other side effects of toxic exposure that have been reported are
headaches, nausea, dizziness, eye and skin irritation and chemical burns. It is important that
proper eye, face and respiratory protection masks are used on gas plant.
7. Ergonomic Hazard
Oil and gas workers might be exposed to ergonomics-related injury risks, such as lifting heavy
items, bending, reaching overhead, pushing and pulling heavy loads, working in awkward body
postures, and performing the same or similar tasks repetitively. Risk factors and the resulting
injuries can be minimized or, in many cases, eliminated through interventions such as pre-task
planning, use of the right tools, proper placement of materials, education of workers about the
risk, and early recognition and reporting of injury signs and symptoms.
8. High Pressure Line and Equipment
Workers might be exposed to hazards from compressed gases or from high-pressure lines.
Internal erosion of lines might result in leaks or line bursts, exposing workers to high-pressure
hazards from compressed gases or from high-pressure lines. If connections securing high-
pressure lines fail, struck-by hazards might be created.
 Ensure the regulator and pipework is appropriate for the type of gas and pressure regime.
 Do not use grease or PTFE tape on threads - this can present an explosion risk and
indicates unsatisfactory seal being made which could leak.
 Ensure the cylinder is secured in a trolley or securely chained/strapped to the wall or
bench.
 Do not store flammable gases near any source of ignition.
9. Electrical and Other Hazardous Energy
Workers might be exposed to uncontrolled electrical, mechanical, hydraulic, or other sources of
hazardous energy if equipment is not designed, installed, and maintained properly. Further,

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administrative controls such as operating procedures must be developed and implemented to
ensure safe operations.
 Have only licensed electricians install, repair and dismantle jobsite wiring.
 Do a thorough check for electrical wiring before cutting through any wall, floor or
ceiling.
 Inspect power tools on a regular basis.
 Check insulated tools for damage before each use.
 Ensure that all electrical components stay dry.
10. Machine Hazard
Oil and gas extraction workers may be exposed to a wide variety of rotating wellhead equipment,
including top drives and Kelly drives, draw works, pumps, compressors, catheads, hoist blocks,
belt wheels, and conveyors, and might be injured if they are struck by or caught between
unguarded machines.
 Machines used for drilling activities generally cause a lot of noise and vibration
which can harm the operator. While using such equipment the operator should
make it a point to wear protective gear like gloves and earplugs.
 It is important to follow OSHA regulations to guard machinery, update equipment
and keep them in good working condition to ensure safe use.
The following OSHA and NIOSH documents provide guidance on recognizing and controlling
these hazards: (Barrier Guard for Draw works Drum at Oil Drilling Sites, Caught-Between
Machine Safety).
11. Gas Flare
A gas flare alternatively known as a flare stack, is a gas combustion device used in industrial
plants such as Gas plant. Fire stacks are primarily used for burning off flammable gas released
by pressure relief valves during unplanned over-pressuring of plant equipment, during plant or
partial plant starts and shutdowns.
When industrial plant equipment items are over pressured, the pressure relief valve is an
essential safety device that automatically releases the gases. The released gases and liquids are
routed through large piping systems called flare headers to a vertical elevated flare.

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Figure :Gas Flare
4.3 Hazard Mitigation Planning & Prevention
 Identification & Evaluating the hazards at the worksite is very important. Many
companies within the oil and gas industry use the Job Safety Analysis Process (also
referred to as a JSA, Job Hazard Analysis, or JHA) to identify hazards and find solutions.
 Establishing ways to protect workers, including developing and implementing safe
practices for:
 Confined space; excavations
 Chemical handling; exposure
 Chemical storage
 Electrical work
 Emergency response
 Equipment/machine hazards
 Fall protection
 Fire protection
 Hot work, welding, flame cutting operations
 Personal protective equipment use
 Power sources (lockout/tag out provisions, safe distance from power lines)

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 Working in the heat, long shifts
 Providing personal protective equipment (PPE). When engineering controls alone
cannot protect worker overexposure to chemicals, noise, or other hazards, the
employer must provide PPE.
 Training of the workers & planning for contractor safety and their training also.

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CHAPTER-05:
Coal and Hard Rock
Import At Tamabil
Port

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5.1 Tamabil Port
Tamabil is a hilly area in Sylhet on the border between Bangladesh and the Indian state of
Meghalaya about 5 km from Jaflong.
It stands on the Sylhet-Shillong Road some 55 km from Sylhet town in Bangladesh.It is well
known for the Bangladesh Last House, which is located on the Bangladesh–India border, and the
Jointa Hill Resort.
5.2 Coal import at Tamabil Border
Coal is s a variety of sedimentary,combustible,solid,organic rocks that are composed mainly of
carbon and different amounts of other components which includes hydrogen, oxygen, sulphur
and moisture.After the decomposition of organic materials that have been subjected to geologic
heat and pressure over millions of years, coal is formed. As it cannot be replenished on a human
time frame,coal is considered as non-renewable resource. Currently 40% of the world‟s
electricity needs is provided by coal. After oil, it is the second source of primary energy, and the
first source of electricity generation in the world. Irrespective of its economic benefits for the
countries, the environmental impact of coal use, especially that coming from carbon dioxide and
sulphur dioxide emissions, should not be overlooked. However, the energy infrastructure of
Bangladesh is changing from a gas based mono-energy to a multiple energy system in which
coal is going to play a vital role. In the country for more than two decades there are significant
coal deposits known to occur, but the development of the coal resources is too little and delayed.
In 2011 in Bangladesh, 2.5% of the electricity generated was supplied by coal and almost 80%
by gas. The country's overall coal production was around 3,000 tons a day in May 2011, from the
only producing state-owned coal mine in Barapukuria, Dinajpur. To cope with the rapid increase
in electricity demand and insufficiency of gas for power generation, the Bangladesh government
is in search for both domestic and imported coal sources to satisfy a momentous portion of its
ambitious power generation expansion plans. The Bangladesh Power Development Board
flagged that the government wanted an additional 12,000 MW in capacity installed by the end of
2016, 24,000 MW by 2021 and 39,000 MW by 2030 in its annual report (2010-2011). To meet
these demands, the country imports 0.8 to 0.85 million tons of coal through Sylhet border from
India every year .
5.3 Hard Rock import at Tamabil Border
Hardrock a term used loosely for igneous and metamorphic rock, as distinguished from
sedimentary rock. These are consolidated rocks like granite or marble. An unlimited reserve of
hard rock consisting of granodiorite, quartzdiorite and gneiss of the Pre-Cambrian has been

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discovered at a shallow depth of 128 m in Maddhapara in the Dinajpur district. Pegmatite, pyrite,
chalcopyrite and siderite have been observed in the vicinity of granodiorite, quartzdiorite and
gneiss. Hard rock deposits are also recorded in Ranipukur and Pirganj inRangpur district at a
depth of 171 m and 265 m respectively, and from Bogra, Joypurhat-Jamalgonj, and Kansat of
Rajshahi district at depths of 2,150 m, 600'667 m and 615 m respectively (Rahman,1997).
Besides these, there are surface deposits of construction materials such as boulders, gravels etc.
at Tetulia-Panchagarh in Dinajpur district; Kaptai-Alikadam-Ukhia-Teknaf-St. Martin's Island in
greater Chittagong district and some other places in greater Sylhet district.
Figure:Hard rock
Imported
Haedrock

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CHAPTER-06:
Blowout in Sylhet
(Sylhet -1 and Sylhet -
4)

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6.1 Blowout:
Blowout is sudden, uncontrolled flow of fluids from the subsurface, when the fluid is gas then it
is known as gas blow out. At overpressure oil, gas or water zone at the subsurface, while the drill
string is penetrated, may cause the forceful flow of fluid (gas, oil or water) into the drill string.
These fluids (gas, oil or water) may come up to the surface and kick the rig floor violently and
create blowout.
6.2 Classification of Blowout:
Blow out can be classified into three broad categories and they are surface, subsea and
underground blowout.
Surface blowout: When the blowout takes place on the surface, it is known as surface blowout.
It can eject the drill string out of the well. The force of the escaping fluid can be strong enough to
damage the drilling rig. In addition, the output of a well blowout might include sand, mud, rocks,
drilling fluid, natural gas, water, and other substances. Again, it can often be ignited by an
ignition source, from sparks or from rocks, or simply from the heat generated by friction.
Sometimes, this incident can be so forceful that they cannot be directly brought under control
from the surface, particularly if there is so much energy in the flowing zone that it does not
deplete significantly over the course of a blowout. In such cases, other wells (relief wells) may
be drilled to intersect the well or pocket, in order to allow killing-weight fluids to be introduced
in depth. The accident of Chattak-2 (Tengratila) occurred on 17 June, 2005; was this kind of
blowout.
Subsea blowout: Subsea wells have the wellhead and pressure control equipment located on the
seabed varying from depths of 10 feet (3.0 meter) to 8,000 feet (2,400 meter). It is very difficult
to deal with a blowout in very deep water because of the remoteness and limited experience with
this type of situation.
Underground blowout: An underground blowout is a special situation where fluids from high
pressure zones flow uncontrolled to lower pressure zones within the wellbore. Usually this is
from deeper higher pressure zones to shallower lower pressure formations. There may be no
escaping fluid flow at the wellhead.

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Figure:Underground Blowout
Causes of Blowout:
Reservoir pressure:Because most hydrocarbons are lighter than rock or water, they often
migrate upward through adjacent rock layers until either reaching the surface or becoming
trapped within porous rocks (known as reservoirs) by impermeable rocks above. However, the
process is influenced by underground water flows, causing oil to migrate hundreds of kilometers
horizontally or even short distances downward before becoming trapped in a reservoir. When
hydrocarbons are concentrated in a trap, an oil field forms, from which the liquid can be
extracted by drilling and pumping. The down hole pressures experienced at the rock structures
change depending upon the depth and the characteristic of the source rock
Formation kick:
 The downhole fluid pressures are controlled in modern wells through the balancing of the
hydrostatic pressure provided by the mud used. If the balance of the drilling mud pressure
be incorrect then formation fluids (oil, natural gas or water) begin to flow into the
wellbore and up the annulus (the space between the outside of the drill string and the
walls of the open hole or the inside of the last casing string set), or inside the drill pipe.
This is commonly called a kick.
 If the well is not shut in, a kick can quickly escalate into a blowout when the formation
fluids reach the surface, especially when the influx contains gas that expands rapidly as it
flows up the wellbore, further decreasing the effective weight of the fluid.

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6.3 Blowout in Sylhet (Sylhet -1 and Sylhet -4)
Haripur Gas Field is known as Sylhet Gas Fields limited. It is a sister concern of PETRO Bangla
under the Ministry of Power, Energy and Natural Resource. It primarily started production of
natural gas and mineral gas in the country.
In quest of natural gas, the then Pakistan Petroleum Limited (PPL) in 1955 commenced drilling
activities at Haripur, a small village of Jaintapur police station in Sylhet district of the former
East Pakistan. As drilling of a well in the structure was progressing, the first discovery of gas in
the country took place in the same year. Unfortunately their effort did not succeed as blow out
occurred in the very first well of the country because of abnormal high pressure. Before the
independence of Bangladesh, 6 wells were drilled in Haripur. Of the six wells, only two wells,
well no. 3 and well no. 6 became operative and the rest were abandoned for various technical
reasons. Haripur structure consists of four layers. These are Tipam, upper Boka Beel, second
Boka Beel and lower Boka Beel.
After the liberation war, Sylhet-7 well, the much discussed well in the history of Bangladesh as
this was the single oil producing well of the country, was drilled at Haripur in 1986. However,
with time a gradual production declining trend had become apparent. After 07 years of more or
less uninterrupted production of total 560869 barrels of crude oil, the well ceased its production
on 14th July, 1994. The well head pressure was zero at that time.
In March 2005 the work over was done on the well and was completed as a gas producer with an
initial production capacity of 15 MMCFD.
The last well, which was drilled in Haripur gas field by Scimitar Exploration Ltd. in 1989, is
Surma 1A well. This well was an appraisal well for oil discovery but oil was not found. Now this
well is producing gas. Recently 3D Seismic Survey has been completed in the field of Sylhet-7
well.
1X30 MMscfd Silicagel type solid desiccant dehydration plant and 68 bbl/day capacity
condensate fractionation plants have been set up in the field to process the gas and condensate
produced from the wells.
6.4 Reasons of blowout in Sylhet (Sylhet -1 and Sylhet -4):
The Sylhet-1 well was drilled to a depth of 2377 meters and then encountered gas, after casing
was set, the blowout got out of control, was ignited and the total rig was destroyed. A large crater
was formed, into which the rig sank. The Sylhet-4 well had a similar blowout when drilled to
only 314 meters below the surface.

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6.5 Effect of blowout in Sylhet:
Owing to the blowout at Sylhet-1 well, a crater was formed and filled with water, creating a large
pond which is still there today and vent gas from the subsurface into the year. The effect of
blowout at Sylhet-4 is more dangerous as well was abandoned then and gas is still venting out
from the fissures in the well site and nearby hill side which often cause fire.
Figure: Blowout in Sylhet (Sylhet -1 and Sylhet -4)
6.6 Precaution of blowout:
To prevent blowout, following steps should be performed:
 The first response to detecting a kick would be to isolate the wellbore from the surface by
activating the blow-out preventers and closing in the well as kick is the first sign of
blowout.
 Sudden change in drilling rate should be monitored.

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 Sudden change in surface fluid rate and sudden change in pump pressure should be
monitored.
 The drilling crew or mud engineer should keep track of the level in the mud pits and/or
closely monitor the rate of mud returns versus the rate that is being pumped down the
drill pipe.
 An increasing mud return rate should be noticed as the formation fluid influx pushes the
drilling mud to the surface at a higher rate.
 The formation pressure should be always kept under mud pressure.
 Automatic blowout preventer should be used.
 Automated drilling rig should be used.

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CHAPTER-07:Jaflong
Quarry Mining

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7.1 Basic information of Rocks in Bholaganj-Jaflong
Hard rock a term used loosely for igneous and metamorphic rock, as distinguished from
sedimentary rock. Hardrocks in Bangladesh are of four types. (i) Maddhyapara subsurface hard
rock (ii) Bholaganj-Jaflong hard rock concretions (Companiganj) (iii) Tetulia-Patgram-
Panchagar hard rock concretions and (iv) Chittagong hilly track sedimentary concretions. The
terms (ii), (iii) and (iv) are usually considered as gravel deposits. The Bholaganj (under
Companiganj Upazilla) hard rock project is approximately 850 km2. The hard rock is mined
following the open pit technique. The worker extracts hard rock by using their hand operating
tools. In so far as the Dupitila formation, this immediately overlies the hard rocks in the region.
The hard rocks are to be extracted from a depth of 2.5 meter to 10meter below the surface.
The Sona Tila gravel bed is equivalent to the lower Pleistocene series and belongs to the
Madhupur clay formation while the Bholaganj gravel bed is equivalent to the upper Pleistocene
to Holocene series. Similarly, the former is weathered and the latter is fresh, hard and high
quality derived from the Khasi-Jaintia hill ranges. The gravels of both beds are of igneous and
metamorphic origins. They have high sphericity and roundness values and as such suggest long
transportation and long time abrasion of the gravel sediment. They are made of river borne
deposit.
7.2 Quarry Mining
A quarry mine is a type of open-pit mine from which rock or minerals are extracted. Quarries are
generally used for extracting building materials, such as dimension stone, construction aggregate,
riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the
requirement for large amounts of aggregate in those materials. The word quarry can include
underground quarrying for stone, such as Bath stone.
Quarries in level areas with shallow groundwater or which are located close to surface water
often have engineering problems with drainage. Generally the water is removed by pumping
while the quarry is operational, but for high inflows more complex approaches may be required.
For example, the Coquina quarry is excavated to more than 60 ft (18 meter) below sea level. To
reduce surface leakage, a moat lined with clay was constructed around the entire quarry. Ground
water entering the pit is pumped up into the moat. As a quarry becomes deeper water inflows
generally increase and it also becomes more expensive to lift the water higher during removal -
this can become the limiting factor in quarry depth. Some water- filled quarries are worked from
beneath the water, by dredging.

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Figure: Quarry Mining
Quarries in level areas with shallow groundwater or which are located close to surface water
often have engineering problems with drainage. Generally the water is removed by pumping
while the quarry is operational, but for high inflows more complex approaches may be required.
For example, the Coquina quarry is excavated to more than 60 ft (18 meter) below sea level. To
reduce surface leakage, a moat lined with clay was constructed around the entire quarry. Ground
water entering the pit is pumped up into the moat. As a quarry becomes deeper water inflows
generally increase and it also becomes more expensive to lift the water higher during removal -
this can become the limiting factor in quarry depth. Some water- filled quarries are worked from
beneath the water, by dredging.
7.3 Crusher
A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust.
Crushers may be used to reduce the size, or change the form, of waste materials so they can be
more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in
rock ore), so that pieces of different composition can be differentiated. Crushing is the process of
transferring a force amplified by mechanical advantage through a material made of molecules
that bond together more strongly, and resist deformation more, than those in the material being
crushed do. Crushing devices hold material between two parallel or tangent solid surfaces, and
apply sufficient force to bring the surfaces together to generate enough energy within the
material being crushed so that its molecules separate from (fracturing), or change alignment in
Quarry
Mining

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relation to (deformation), each other. The earliest crushers were hand- held stones, where the
weight of the stone provided a boost to muscle power, used against a stone anvil. Querns and
mortars are types of these crushing devices. There are two types of crushers (small and large) are
found in Bholaganj area. Small size crusher are named “Tom tom” by local people.
7.3.1 Production of Small Size Crusher: The production of a small size crusher is 700-800
ft3/day. The number of total small size crushers is 160, so according to this the total production
by small size crushers are 45000 ft3/day and the annual production of crushed rock is 1.65 x 107
ft3.
7.3.2 Production of Large Size Crusher: The production of a large size crusher is 2500-3000
ft3/ day. The total number of large size crushers is 350, so according to this the total production
by large size crusher is 962500 ft3/ day.
7.4 Hard Rock
Hard rock is known as the building material which usually used in construction. Bholaganj is one
of the main sources of hard rock and are used in construction all over the Bangladesh. But no
appropriate engineering technology is used here to extract this hard rock. Local people are
extracting this hard rock by using hand operating tools. At least 9,000 people including 3000
women and 1000 children is working as stone laborer, on the bank of the Dholai River, in
Bholaganj, Companianj, Sylhet. The average income of the stone laborers is less than 150 taka
per day. Stone extraction goes on in the area for about eight months a year, except the rainy
season. On an average 300 truck load of stones are sent to Sylhet and other parts of Bangladesh
every day. Based on this, local people get involve in rock business and crushing business.
Maximum labors in crusher mills and workers who working in quarry for extraction purposes are
local people of Sylhet district. Not only local people but also people of other districts involve
here. An unemployed people can get involve here easily. So it is clearly visible that a great
working place has been created here. These rocks of Companiganj are assets of local area of
Bangladesh. Future study is required to extract these economically valuable rocks by
environment friendly way using the modern mining technology.
7.5 Sylhet Limestone
The term Sylhet limestone as a rock unit was first used by F.H.Khan(1963).The formation is
exposed on the left bank of Dauki river near the Bangladesh-Meghalaya border. (Lat N251053.5
Long E920105.5)The outcrop forms an inlier surrounded by recent deposits and rock of the

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Barail group. It is the oldest (Eocene) rock of the investigated area. Limestone is a hard friable
rock, thus are sometime fosiliferous.
Figure: Outcrop of Sylhet Limestone.
The grey coloured, fossiliferous highly compacted limestone offers a variety of fossils from disk
shaped. The hard limestone is highly jointed and fractured .The brecciated limestone occurs due
to large Dauki Fault.The assemblages of dominantly large microfossils indicate shallow water,
continental shelf zone. Fault bractia, formation missing, topographic change and different deep
direction are indicating the presens of Dauki Fault.
Figure :Fault Bractia, Dauki Fault
Sylhet
Limestone

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Figure: Sudden Topographic change due to Dauki Fault
The lithologic description of Sylhet limestone indicates it was formed in a warm, shallow marine
environment of deposition. The Eocene was a period of stable slowly subsiding shelf condition
in the Bangladesh area and was not yet strongly influenced by the continental collision of India
and Asia that began in Late Paleocene. As a result there was no disturbance of any river and that
quite environment was favorable for the inhabitation of marine organisms which we found as
fossils in Sylhet limestone.
Sudden
topographic
change

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Conclusion
Energy sector may be defined as the key of the world economy. Natural resources like natural
gas play an important role in this regard. Natural gas is main energy source of our power
generation and another chemical industry. It is also used as raw material in several industries.
Petrobangla has excellent consequences in survey exploration, drilling and gas processing.
Different kinds of processing plants exist in our country. Molecular Sieve Turbo Expander
(MSTE) plant is one of the modern technologies of the world. Another conventional technology
like silica gel and glycol extraction plant is used. We have used ASPEN HYSIS, Auto CAD and
MS Visio in different parts of this report. Plant training is like a bridge between academic and
practical knowledge. As plant trainee we have been introduced with the different processing
plants, fractionations, maintenance, utilities, metering and also with drilling. From this sessional
course we have learned application of basic engineering courses in actual field of process
designing, development of a clear concept on real plant scenario, process optimization-selection
of best suitable process for the plant and designing a new plant that meets economic feasibility.

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References
1) Datasheet from SGFL, Kailashtilla field
2) www.petrobangla.com
3) www.bapex.com.bd
4) Donald L. Kaltz and Robert L. Lee; Natural Gas Engineering: production
and storage
5) Plant Design & Economics For Chemical Engineers (Max Peters).pdf
6) https://www.osha.gov/SLTC/oilgaswelldrilling
7) Sam Mannan (Editor) (2005). Lee's Loss Prevention in the Process
Industries: Hazard Identification, Assessment and Control, Volume 1 (3rd
ed.)

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