ARL Boiler House Report

ARL Boiler House Report

INTRODUCTION:Attock Refinery Limited (ARL) was incorporated as a Private Limited Company in November, 1978 to take over the business of the Attock Oil Company Limited (AOC) relating to refining of crude oil and supplying of refined petroleum products. It was subsequently converted into a Public Limited Company in June, 1979 and is listed on the three Stock Exchanges of the country. The Company is also registered with Central Depository Company of Pakistan Limited (CDC).

Original paid-up capital of the Company was Rs 80 million which was subscribed by the holding company i.e. AOC, Government of Pakistan, investment companies and general public. The present paid-up capital of the Company is Rs 454.896 million.

ARL is the pioneer of crude oil refining in the country with its operations dating back to 1922. Backed by a rich experience of more than 80 years of successful operations, ARL’s plants have been gradually upgraded/replaced with state-of-the-art hardware to remain competitive and meet new challenges and requirements.

It all began in February 1922, when two small stills of 2,500 barrel per day (bpd) came on stream at Morgah following the first discovery of oil at Khaur where drilling started on January 22, 1915 and at very shallow depth of 223 feet 5,000 barrels of oil flowed. After discovery of oil in Dhulian in 1937, the Refinery was expanded in late thirties and early fourties. A 5,500 bpd Lummus Two-Stage-Distillation Unit, a Dubbs Thermal Cracker, Lubricating Oil Refinery and Wax Purification facility and the Edeleanu Solvent Extraction unit for smoke-point correction of Kerosene were added.

SERIES OF FIRSTFirst refinery of the region (1922) First to start dispensing major products through pipeline using computerized metering system (1987) First to produce low sulfur furnace (less than 1%) (1998) First to produce low sulfur diesel (less than 0.5%) (1998) First to achieve ISO 9002 certification for quality control laboratory (1999) First to produce low lead premium gasoline direct from refinery process (1999) First to produce polymer modified asphalt (2001) First refinery/first petro-chemical plant / first major industry to get ISO 9001:2000 certificate (2001)

M.ABID SHARIF (TEO-331649) 1


First refinery / first petrochemical plant/first major industry to get ISO 14001 certificate (2002) First major industry to get OHSAS 18001 certification (2006).

There were subsequent discoveries of oil at Meyal and Toot (1968). Reservoir studies during the period 1970-78 further indicated high potential for crude oil production of around 20,000 bpd. In 1981, the capacity of Refinery was increased by the addition of two distillation units of 20,000 and 5,000 bpd capacity, respectively. Due to their vintage, the old units for lube/wax production, as well as Edeleanu, were closed down in 1986. In 1999, ARL commenced JP-1 pipeline despatches, and in 2000, a Captive Power Plant with installed capacity of 7.5 Megawatt was commissioned. Another expansion and upgradation project was completed in 1999 with the installation of a Heavy Crude Unit of 10,000 bpd and a Catalytic Reformer of 5,000 bpd. ARL’s current nameplate capacity stands at 40,000 bpd and it possesses the capability to process lightest to heaviest (10-65 API) crudes.

ARL MILESTONES1910 Beginning of operations by AOC 1915 First discovery of oil at Khaur District by AOC 1922 Commissioning of two small refining units at Morgah near Rawalpindi with the capacity of 2,500 BPD 1937 Discovery of oil in Dhulian and installation of Dubbs and Lummus Plants with the capacity of 5,500 BPD 1968 Discovery of oil at Meyal and Toot oilfields 1978 Incorporation of ARL 1979 Conversion of ARL into a Public Limited Company and its listing on three stock exchanges of the country 1981 Refining capacity was increased by the addition of two distillation units of 5,000 & 20,000 BPD capacity each 1987 Commissioning of dispatches of petroleum products through pipeline to Oil Marketing Companies (OMCs) withcomputerized metering 1996 Effluent Treatment Plant 1999 Expansion and upgradation project with the installation of Heavy Crude Unit of 10,000 BPD and CatalyticReformer Complex of 5,000 BPD 2000 Commissioning of Captive Power Plant with the capacity of 7.5 MW 2001 ISO-9001: 2000 certification 2001 Production of Polymer Modified Bitumen (PMB) 2002 ISO-14001 certification 2005 ARL's current nameplate capacity is 40,000 BPD and has the capability to process heaviest to lightest



(12-65 API) crudes 2006 OHSAS - 18001 certification

ARL has vast range of operation therefore it needs versatility of process. This flexibility can’t be achieved without utilities operations. Utilities are the backbone of any process industry and in these utilities operations steam generation got the key importance. Steam is generated for variety of purposes. In case of refinery, steam is used mainly for stripping purpose. Other facilities of utilities operations here in ARL are instrument air, service air, plant water, soft water, drinking water, raw water, firewater, cooling water, fuel oil for plants and soda plant facility.

A boiler is an enclosed vessel that provides a means for combustion heat to be transferred into water until it becomes heated water or a gas (steam). The steam or hot water under pressure is then usable for transferring the heat to a process. Water is a useful and cheap medium for transferring heat to a process. When water is boiled into steam, its volume increases about 1,600 times, producing a force that is almost as explosive as gunpowder. This causes the boiler to be an extremely dangerous item that must be treated with utmost respect. Boilers were used in crude fashions for several centuries but development was slow because construction techniques were crude and the operation was extremely dangerous. However, by the industrial revolution of the mid 1800’s boilers had become the main source of energy to power industrial operations and transportation. The use of water as a heat transfer medium has many advantages. Water is relatively cheap, it can be easily controlled, the gas in invisible, odorless, and extremely high purity. The process of heating a liquid until it reaches it's gaseous state is called evaporation. Heat is transferred from one body to another by means of (1) radiation, which is the transfer of heat from a hot body to a cold body through a conveying medium without physical contact, (2) convection, the transfer of heat by a conveying medium, such as air or water and (3) conduction, transfer of heat by actual physical contact, molecule to molecule. The heating surface is any part of the boiler metal that has hot gases of combustion on one side and water on the other. Any part of the boiler metal that actually contributes to making steam is heating surface. The amount of heating surface a boiler has is expressed in square feet. The larger the amount of heating surface a boiler has the more efficient it becomes. The measurement of the steam produced is generally in pounds of water evaporated to steam per hour.



Gallons of water evaporated x DENSITY OF WATER i.e. (8.3 pounds/gallon water) = Pounds of steam In fire-tube boilers, the term boiler horsepower is often used. A boiler horsepower is 34.5 pounds of steam. The measurement of heat is in British Thermal Units (Btu’s). A Btu is the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit. When water is at 32 oF it is assumed that its heat value is zero. The heat required to change the temperature of a substance is called its sensible heat.

To change the liquid (water) to its gaseous state (steam) an additional 970 Btu’s would be required. This quantity of heat required to change a chemical from the liquid to the gaseous state is called latent heat. The saturation temperature or boiling point is a function of pressure and rises when pressure increases. When water under pressure is heated, its saturation temperature rises above 212 oF. This occurs in the boiler. For example the boiler is operating at a pressure of 100 psig, which gives a steam temperature of 338 oF or 1185 Btu’s. When heat is added to saturated steam out of contact with liquid, its temperature is said to be superheated. The temperature of superheated steam, expressed as degrees above saturation, is referred to as the degrees of superheat.

BOILER TYPES:There are virtually infinite numbers of boiler designs but generally they fit into one of two categories: (1) Fire-tube or as an easy way to remember "fire in tube" boilers, contain long steel tubes through which the hot gasses from a furnace pass and around which the water to be changed to steam circulates, and (2) Water-tube or "water in tube" boilers in which the conditions are reversed with the water passing through the tubes and the furnace for the hot gasses is made up of the water tubes. In a fire-tube boiler the heat (gasses) from the combustion of the fuel passes through tubes and is transferred to the water, which is in a large cylindrical storage area. Fire-tube boilers typically have a lower initial cost, are more fuel efficient and easier to operate but they are limited generally to capacities of 12T/H and pressures of 250 psig. Vertical tubeless boilers are used for small loads but really do not fit into either category as they do not have tubes. Boilers and pressure vessels are built under requirements of the American Society of Mechanical Engineers or ASME referred to as the "ASME Code."



STEAM BOILER SYSTEMS: The feed water system provides water to the boiler and regulates it automatically to meet the demand for steam. Valves provide access for maintenance and repair. The steam system collects and controls the steam produced in the boiler. Steam is directed through piping to the point of use. Throughout the system steam pressure is regulated using valves and checked with steam pressure gauges. The steam and feed water systems share some components. The fuel system includes all equipment used to provide fuel to generate the necessary heat. The equipment required in the fuel system depends on the type of fuel used in the system. All fuels are combustible and dangerous if necessary safety standards are not followed. Fuels commonly used are nuclear fusion, electricity, the wastes of certain processes and fossil fuels. The approximate heat value of certain fossil fuels:

Natural Gas 1,000 Btu/Cubic foot F Oil 18,750Btu/lb Coal 12,500Btu/ton Wood (Dry) 8,000Btu/ton Wood (Wet) 4,000Btu/ton

In a fuel oil fired boiler plant, fuel oil leaves the tank through a suction line and duplex strainer traveling then to the fuel oil pump. The fuel oil is then forced through the pump and then through the discharge line. From the discharge, line some fuel oil is burned and some returned to the tank through a regulating valve. In a natural gas, fired plant gas is supplied at a set pressure, which varies depending on the gas source. Gas systems are low pressure or high pressure. Through the regulator, gas is drawn into the burner and mixed with air supplied by a blower. This mixture is directed to the burner where it is ignited with the pilot light. In a high gas pressure system, gas passes through the regulator and gas is reduced to the proper pressure for the burner. Some boilers have combination burners, which can burn gas or fuel oil or a combination of both gas and fuel oil. Coal fired boilers use mechanical feeders or stokers to feed fuel to the burner at a consistent rate. For example, in a chain grate stoker coal is fed through the hopper and regulated before passing under the ignition arch. The coal continues on a conveyor, which carries the ignited coal slowly under the heating surface. Ash, slag and unburned parts or clinkers are discharged at the other side of the conveyor.



The draft system regulates the flow of air to and from the burner. For fuel to burn efficiently the right amount of oxygen must be provided. Air must also be provided to direct the flow of air through the furnace to direct the gases of combustion out of the furnace to the breaching. A forced draft system uses a fan to force (or push) air through the furnace. An induced draft system uses a fan to draw (or pull) air through the furnace. A combination or balanced draft system uses forced and induced draft fans. Gases of combustion enter the stack from the breaching and are released to the atmosphere. Combustion may be defined as the rapid chemical combination of oxygen with the combustible elements of a fuel. Only three combustible, chemical elements are of any significance: carbon, hydrogen and sulfur. The boiler combustion furnace in which the fuel burns provides a chamber in which the combustion reaction can be isolated and confined so that it can be controlled. The convection surfaces are the areas to which the heat travels that are not transferred in the combustion furnace. Here additional heat is removed. The burner is the principal device for the firing of oil and/or gas. Burners are normally located in the vertical walls of the furnace. Burners along with the furnaces in which they are installed, are designed to burn the fuel properly.

STEAM TO WATER CYCLE:In a steam heating system, steam leaves the main steam line and enters the main steam header. From the main header piping directs the steam to branch lines. Branch lines feed steam through a riser to the steam heating equipment. At the heating equipment, heat is transferred to the building space. As the steam releases heat to the building space and is cools it turns back to water or condensate. The condensate is separated from the steam by a steam trap. The steam trap allows condensate to pass but not the steam. The condensate passes through the condensate return line and is collected and directed back to the boiler to repeat the steam to water process. Separation of solids in the water occurs in the boiler but since it is operating continuously and at higher temperatures this "buildup" can occur very rapidly. When this occurs the heat transfer cannot be achieved, as readily which requires more fuel to produce the steam. If continued unchecked damage to the metals in the boiler shell and tubes will result. Pretreatment equipment such as softeners, de-mineralizes, etc. are used to remove as much of the dissolved solids as possible before they get to the boiler. To remove the solids that continue to the boiler chemicals are added to react with the solids creating sludge. This



sludge is then periodically removed by opening valves from the bottom of the boiler and relieving it to the drain. This process is called blow-down. Waterside problems can also shorten boiler life from corrosion brought on by the oxygen content in the feed-water. Pretreatment for the removal of oxygen is performed in a deaerator but here again the removal is not complete and chemical additions are made to aid in improving the oxygen removal process. The water supplied to the boiler that is converted into steam is called feed-water. The two sources of feed-water are: (1) Condensate. Or condensed steam returned from the processes and (2) Makeup water (usually city water), which must come from outside the boiler room and plant processes. For higher boiler efficiencies, the feed-water can be heated, usually by economizers.

PROCESS DESCRIPTION OF ARL BOILER HOUSE:Raw water for steam production is drawn from Reservoir # 3 contains both the suspended and dissolved impurities. Thus hard in nature, cannot directly be admitted into the Boiler until treated physically & chemically. The details of reservoir no. 3 is as follow

Name Reservoir No.03

Shape L-Shape

Depth 16'

Capacity 1920000 gal

SourceShahpur Well No.02, 03, 04, 06; Sawan

Type Well & River Water

Quantity 1" = 10,000

Quality Dated: 26-02-07

PH 7.21

TH 400

TDS 451

Turbidity 0

Cl 59.64

Ca-H 310

M-Alkalinity 390

Mg-H 90



Drinking Water standard @ WHO

PH 6.5-8.5

TH <500

TDS <1000

Turbidity <3.25

Cl <600

Ca-H

M-Alkalinity

Mg-H

Fe <1.0

Cl <1.0

The quality of the reservoir water is checked weekly on Monday and maintained according to WHO standards for drinking water. Chemical laboratory personals are responsible for the tests and submit these results to shift engineer of boiler house.

In ARL Boiler House (Utility Section), Four centrifugal pumps each with 100 Psi discharge pressure are housed, three standbys while one is in operation. From these pumps water is distributed as plant water, cooling water for merox and C-101 compressor, cooling of ID fan of Boilers 3 & 4, cooling of steam compressor, powerhouse and as make-up water for steam generation through water header distribution. Specification and other details of these pumps are as follow

No. Of Make up Water Pumps 4

Name B, C

Manufacturer KSB Pumps

Type Centrifugal EIA-100/33

P out 96 Psi or 3.5 Kg/cm2

RPM 1450

Capacity 500 gpm

Head 100 ft

H.P 19.4

Motor Specification

Type ILA4183-4 AA 90

Motor ampere 34

Motor Horse Power 25

RPM 1460



Voltage 400/440

No. Of Make up Water Pumps 4

Name A,D


Type Centrifugal EIA-80/26

P out 96 Psi or 3.5 Kg/cm2

RPM 2900

Capacity 150 gpm

Head 243 ft

H.P 23.01

Motor Specification

Type ILA4206-2 AA 60

Motor ampere 57

Motor Horse Power 40

RPM 2950

Voltage 380-400

The raw feed water being pressurized is allowed to enter the sand-filter-tank top after a strainer in-line of make-up water supply line. We have facility of one in service and other standby line for make-up water supply. Any maintenance or other jobs in water lines allow the smooth operation by other. A connection is also given to brine water pump for its priming and to soda plant facility for dilution and operational need. All the three sand filter tanks remain in operation/ running. The bottom furnishes the turbidity-free or much lowered TSS (Total Suspended Solids) feed water. A hosepipe taken from filters discharge serves in brine solution preparation by supplying raw water to the brine pit. Details of filters are as follows

NamePermutit Filters

No of Items 3

Volume

Filter Media Anthracite

Mesh Size

Volume of Filter Media

Operational Duration before Backwash

P in 70 Psi



P out 50 Psi

Temperature Ambient Softener receives hard water from top, where Amberlite IR 120 Resin granules through ion exchange method, make water soften by accepting the hardness-producing –ions (Mg+2 & Ca+2) respectively, leaving the system water with soft ions (Na+1). Regeneration of exhaust Resin bed is carried out with 11w/w NaCl brine solution. Brine solution is supplied to softeners for regeneration from brine solution tanks via brine solution pump. Filtered water is taken from the inlet of softner-B line for ammonia solution preparation, which is used in deaerator for PH control. Specifications of softners are as follows

Name Na-zeolite softnersNo of items 3Type Gel type strongly acidic cation exchange resinP in 46 Psi or 3 barP out 35 Psi or 2 barDesign Temperature 100 FVol of Vessel (Capacity) 3.5 m3Vol of Media 1826 Liter eachType of Filter Media Sulphonated Polystyrene ResinResin Size 0.64 mmSize of Nozzle 0.25 mmOperational Duration 370 tons of Water before exhaustionRegenerationChemical Used BrineQuantity 8.2 m3/hrQuality 11 w/w of NaClDesign Pressure 72.6 PsigCorrosion Allowance 0Empty weight of Vessel 1600 KgMaterial Shell HR 275Thickness 6 mmSize (mm) ID 1400 X 2200 LGTest Pressure 95 PsigRadiography Spot

Basis for softner DesignApperance ClearPH 7.5TS 412 ppmOdour/Taste Odourless/tastelessChlorides 36 ppm



Sulphates 10 ppmTotal Hardness 247 ppmAlkalinity as CaCO3 270 ppmIron 0.2 ppmCalcium 190 ppmMg 57 ppmLead NilZinc NilP-Alkalinity NilM-Alkalinity 275 ppmTSS 50 ppm

Salt SpecificationPurity 97%Water Content NilInsoluble Matter 0.10%Sulphate SO4 -- 1%Ca ++ and Mg ++ 0.50%Soluble Iron UndetectableSand or Clay NilSoluble Alkalinity as CaCO3 Nil After the softening of the raw water one line goes to Tanks 152,153,154 for the storage of soft water whose level are maintained at 100%. From the same line of soft water a connection is taken for the process of producing steam. Low lift pumps are installed to increase the pressure up to system requirement. Specification details of these pumps are as follow.

Name Low Lift pumps

No of Items 2

Manufacturer KSB

Type Centrifugal Pump ETA 40/20 AR

Capacity 38 TPH

Head 91 m

Total Head 4 BarG

Pump Input HP 10.35

RPM 2900

Suction 30 Psi

Discharge Pressure 6.3 Bar or 88 Psi

Temperature 45 C



Permissible Suction Lift 10 feet

Liquid Soft Water free from sand & Chemicals

Motor Specification

Manufacturer Siemens

Drive Rating 15 HP

V 400

RPM 2940

PF 0.86

Rotor KL 16

A pressure regulating assembly is attached with low lift pumps to regulate the system pressure and works on the system set pressure settings. After the low lift pumps the soft water is distributed into three branches one goes directly to deaerator which acts as bypass line for the heat exchangers train, one to Heavy Crude Unit HCU for the steam production in Kettle re-boiler for the system requirement and one to the heat exchangers train. The two low-lift pumps (~ 6 kg/cm2 discharge pressure each), one working while other being standby, takes the soft water after passing through angle-type strainer & pre-heats it in the heat exchangers no.02 & 03 with the exhaust of Lummus steam. The heating media of heat exchanger no.01 comes from flash vessels that receive CBD and IBD of Descon Boilers system. There are three parallel heat exchangers installed with no pressure and temperature gauges. There details should be taken from Technical Services Department.

From the pre-heaters train soft water goes to mechanical deaerator where the oxygen and other dissolved gases are stripped off the water by steam. Here condensate is also showered along with soft water to make the condensate recovery system water and energy efficient. For this purpose a pump with a stand by arrangement is installed which showers the recovered condensate whose specifications are as follows.

Name Condensate pumps

No of Items 2

Type ETA 50/16

Head 80 feet

BHP 2.86

RPM 2800

Flowrate 65 GPM



Motor Specification

HP 5

V 400

A 7.1

PF 0.88

RPM 2895

Temperature 40 C

We have facility of pumping condensate back to plants on their demand through pumps whose specifications are as follows. Also if plants need low temperature condensate, the condensate to plants pump pumps the condensate to heat exchanger no.01 and after achieving required temperature condensate are sent to plants.

Name Condensate to Plants Pumps

No of Items 2


Type MOVI 32/5

Capacity 15 IGPM

Head 345 feet

HP 3.35

RPM 2870

Motor Specification

Rotor KL 16

A 11.2

V 380-400

HP 7.5

PF 0.88

RPM 2950

Temperature 40 C

The pressure in deaerator is slightly above the atmospheric pressure and maintained at 0.06 Kg/cm2 gauge. This serves as the mechanical de-aeration system to remove oxygen and carbon-di-oxide in boiler feed water. Specifications of deaerator is as under

Type Mechanical Deaerator System



Manufacturer Descon Engineering Limited

Design Temperature 120 C

Design Pressure 150 PsiG

Hydrotest Pressure 187 PsiG

Capacity 39.6 T/H

Diameter 2200 mm

Shell Thickness 10 mm

Head Thickness 10 mm

Only oxygen scavenger i.e. Na sulphite (19P) is used into the Deaerator. All the rest chemicals (scale inhibitor—Nalco 72210—phosphate based & alkaliner NH3 gas) are injected as per demand into the discharge of Feed Water Pump whose specifications are as follow

Name Feed Water Pumps

No of Items 3

Capacity 30 TPH

Total Head 16 barG

Pump Input 27.66 HP

Drive Rating 40 HP

Liquid Soft water

Temperature 105 C

RPM 2900

Discharge Pressure 17 Kg/cm2

Motor Specifications

V 400

A 53.8

HP 40

PF 0.87

RPM 2950

Rotor KL 16

Temperature 50 C

Boiler Feed Water



General Specification Clear, Color less and free of mud

PH Value at 25 C < 9

Hardness < 0.02 meq/Kg

Oxygen as O2 < 0.02 mg/Kg

Carbon Dioxide as CO2 < 25 mg/Kg

Total Iron as Fe < 0.1 mg/Kg

Total Copper as Cu < 0.005 mg/Kg

Oil < 1 mg/Kg

Boiler Water

PH at 25 C > 9

P-Alkalinity < 0.1-1 meq/Kg

Oxygen as O2 < 0.02 mg/Kg

Carbon Dioxide as CO2 < 25 mg/Kg

Total Iron as Fe < 0.1 mg/Kg

Total Copper as Cu < 0.01 mg/Kg

Oil < 1 mg/Kg

At ~ 16 kg/cm2, the feed water pump discharge directs to all the five Boilers (Descon & B&W). This soft water then passes through the economizer, absorbing the much valuable energy contents from the flue gases. Details of Descon system are as under but no information is gathered on B & W Boilers.

Type Fire Tube Boiler

Manufacturer Descon Engineering Works

No of Items 3

Boiler Data

Continous Steam Output 12 T/H

Design Pressure 15 BarG

Operating Pressure 12.5 BarG

Saturated Steam Temperature 193.3 C

Feed Water Temperature 105 C

Water Content at NWL (Normal Water Level) 22.5 m3

Water Content for Hydraulic Test 35.8 m3

Normal Water Level NWL above the Center 657 mm



line of Boiler

High Water Level HWL above the NWL 120 mm

Low Water Level LWL below the NWL 50 mm

Low low Water Level LLWL below the NWL 70 mm

Drum Safety Valve Set Pressure 14.0 BarG and 16.5 BarG

Efficiency Of Boiler

Oil Firing 90 +- 2%

Gas Firing 90 +-2 %

Boiler Dimensions

Diameter Outer 3200 mm

Length 6400 mm

Height 3480 mm

Furnance Volume 8.56 m3

Thickness of Main Boiler Drum 20 mm

Thickness of End Plates 27 mm

Thickness of Fuel Duct 13-15 mm

Man Hole size 320 X 420 mm

Type of Flue Duct Corrugated

Heating Surfaces

Convection Heating Surface 259.86 m2

Radiant Heating Surface 30.65 m2

Economizer Heating Surface 23.70 m2

Total Heating Surface 314.28 m2

Temperatures

Flue gas Temperature at Furnance Outlet 120.7 C

Flue Gas Temperature After Boiler 232.5 C

Flue Gas Temperature After Economizer 150 C (On Gas)

175 (On Oil)

Type Water Tube Boiler

Manufacturer Bobcock & WellCock Company

No of Items 2



Boiler Data

Continous Steam Output 7 T/H

Boiler HydroTest Pressure 20 Kg/cm2

Operating Pressure 13 Kg/cm2

Saturated Steam Temperature 195 C

Feed Water Temperature 105 C

High Water Level HWL Alarm 80%

Low Water Level LWL 40%

Drum Safety Valve Set Pressure 218.5,219,220 Psi

Super Heater Safety Valve 217 Psi

Efficiency Of Boiler

Oil Firing

Gas Firing

Economizer Hydro Test Pressure 19 Kg/cm2

Boiler Dimensions

Diameter Outer

Length

Height

Furnance Volume

Thickness of Main Boiler Drum

Thickness of End Plates

Man Hole size

Heating Surfaces

Convection Heating Surface

Radiant Heating Surface

Economizer Heating Surface

Total Heating Surface



Temperatures

Flue Gas Temperature After Boiler

Flue Gas Temperature After Economizer 165 C

220 C

The total average steam production is ~ 17-18 T/H. CBD (Continuous Blow Down) from the Boilers ~ 3 T/H, is forwarded to flash vessel where the steam enters the heat exchanger as discussed earlier, & the bottom is sent to condensate tank. Condensate from the plants also comes to the condensate tank where soft water is showered to recover the treated water. This recycled water is used in de-aerator. The steam from combined header is distributed to all the units.

The complete PFD of the ARL boiler house with water, steam, fuel oil, fuel gas, service and instrument air is drawn and delivered to the Mr. Muhammad Anwar as future assistance and helpful material for newcomers trainees.

WATER PUMP HOUSE FACILITY:There are 09 pumps provided for lummus vacuum creation, cooling of lummus return in spray pond and maintaining pressure for the firewater network. Usually one pump is in service for all these operations and remaining is standby and used when needed. Reservoir no. 01 is used for lummus cooling water supply that is a open re-circulating cooling system. Reservoir no.02 is used for maintaining pressure in fire network. One pump is used for circulation of eye wash water within the refinery with one standby pump too. These pumps take water from a tank just outside the water pump house building. In case of emergency or shut down of cooling tower no.01 ARL has facility of providing cool water to HBU-1 and HBU-2 taken from reservoir no.02. Three pumps are provided for maintaining 45 Psi pressure in firewater network continuously. One is in service while the rest of two are standby. Diesel engine are also for the same job of firewater in case of emergency and the increase the pressure to 80 Psi. The complete flow diagram of pumping water network is drawn in the water pump house. Instead of these pumps there are three compressors running namely C-1, C-10 and C-15. Main objective of these compressors is to supply service air for the whole refinery.

DRINKING WATER TREATMENT PLANT:Potable water for the whole refinery and the attached colony is treated and provided under the responsibilities of drinking water treatment plant. The water coming from the same water line of shahpur is



delivered to the three clarifiers where alum and chlorine is added for coagulation/flocculation and disinfectant purposes. The sludge from the clarifiers in regularly drained by opening the mud valves. Water is then sent to three sand filters that receive water and remove any turbidity. Usually one sand filter is in service. Clear water is passed through charcoal filter and through a tank where again chlorine is added. Water is then stored in reservoir no.04 and pumped in the whole drinking network for usage.

SUGGESTONS FOR ARL BOILER HOUSE OPERATION:I. Newcomer trainees should be provided with the previous work of

Trainee Engineer and should be encouraged to work on the same basis with the innovation in learning procedure for the next trainee.

II. For example, Firstly the immediate next trainee should draw all the PFD and P&ID on computer then the next trainee should check and modify it where needed then the next trainee should cascade the instruments and respective actions through control assemblies.

III. Also missing data of facilities and equipments should be searched and maintained on the foundation laid by me and improve data management for example making tables and charts in interpolating data like all the plant’s pump on one chart/table with all specification and critical parameters.

IV. Then focus on process parameters and try to add as much options as one can for the smooth operation. For example note down in report all the actions that can be taken in case of level drop of de-aerator.

V. Preventive maintenance should be adopted rather on-demand maintenance which I have seen in boiler house. For instance if two feed pumps are running then maintenance of all the instruments (gauges), filters/strainers and control assemblies of the third one should be done. Similarly for filters, make-up water pumps, low-lift pumps, brine pumps, soda pumps and corrosion of soda tanks etc.

VI. Majority of gauges and instruments are out of order also too much critical places don’t have even one gauge like heating train of soft water with no temperature and pressure gauge, even the readings mentioned in log sheet are written with no presence of any gauge at all.

VII. Permutit filters should be regularly backwashed after every three days as chocking and pressure drop problem is seen very often.

VIII. Turbidity test should be conducted in every shift for the assurance of smooth operation of permutit filters.

IX. Na-zeolite resin has spent its life. The problem of pressure drop is very often, which is due to chocking of the softners. Reduction in



size of resin and low quality raw water after permutit filters is responsible for chocking of softners and their nozzles.

X. One feed pump can handle three boilers in operation as its design capacity match the system requirement. Also softners should be attended on priority basis instead of looking for other options like running two low-lift pumps with condensate to de-aerator pump etc.

XI. Can adopt graphical representation of data of daily log.XII. Softners performance curves from the softners daily operational

parameters to overcome any disturbance in the system.XIII. Should maintain and build technical data sheets of all the facilities

and equipments in the vicinity.XIV. Method to control combustion air for B&W boilers as dampers are

stuck and atomizing steam can’t do it. Also ID fan damper is fully open or close.

XV. Na-phosphate is added in minimum flow line but it will form sludge and possibility of blocking line.

XVI. All gauges and instruments should be in one system of units.XVII. View the possibilities of installing solar energy boilers for steam

generation.


ARL Boiler House Report

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