VOCATIONAL TRAINING REPORT ON INSTRUMENTATION

SUBMITTED BY:

GAURAV RAI (2 nd Yr)

IET, BUNDELKHAND UNIVERSITY, JHANSI

BRANCH- INSTRUMENTATION ENGG.

I am highly thankful to KRIBHCO SHYAM FERTILIZER Ltd., piprola, shahjahanpur which gives me an opportunity to complete my vocational training successfully.

I express my deepest sense of gratitude and humble regards to my honourable and esteemed guides Mr. K.K. Rana (Ammonia

Inst.) and Mr. Dhananjaya Singh (Urea Inst.) under whose regular guidance, constant supervision and inspiring encouragement I completed my training.

I wish to record warm regards to Mr. S.C. Nayak (H.O.D Inst.), Mr. R.K. Shrivastav (Offsite Inst.), Mr. R.C. Shukla (Amm. Inst.), Mr. R.K. Hooda (Urea Inst.) and Mr. Tilak Dey (Inst. Workshop)

for educating us with adequate knowledge and providing adequate facilities during training.

I extend my sincere thanks to Mr. Avinash Jha, R.K.S. Yadav, Mr. S.N. Singh, Mr. Deepak Dutt, Mr. Kamlesh Bhandari, Mr. Shivanshu Pathak and Mr. Sharad Tripathi for providing me their able guidance.

CONTENTS1. Introduction About KSFL

2. Description of

Urea plant

Offsite plant

Ammonia plant

3. Introduction to instrumentation

4. Measuring instruments

Pressure

Temperature

flow

level

5. Transmitters

6. Control valve

7. I/P signal converter

8. Distributed communication system

9. Environmental policy at KSFL

10. Conclusion

THE COMPANYThe Company was incorporated on December 8, 2005 pursuant to a joint venture agreement between KRIBHCO and Shyam Group to acquire the urea manufacturing facilities at Shahjahanpur from Oswal Chemicals & Fertilizers Ltd. in the share holding ratio of 60:40. Effective March 30, 2009 the shareholding ratio of KRIBHCO and Shyam group is 85:15. The management control of the Company rests with KRIBHCO, a cooperative society engaged in manufacturing nitrogenous and bio-fertilizers since 1980. KRIBHCO’s long and valuable experience in fertilizer sector provides the Company the advantage of their management expertise and business know-how. The Company leverages on the extensive marketing and distribution network of KRIBHCO, under which our products are marketed. The Company also has access to ’, ‘ ’ brand, which is a well established and respected brand amongst farmers and co-operative societies across India.

UREA ...

FERTILIZERS:-Any material which supplies one or more

of the chemical elements required for the plant growth is called a fertilizer.

Urea is an important fertilizers used by farmers for proper growth of the crops.

PROPERTIES OF UREA

It is a white crystalline chemical.

It is saline in taste.

It is readily soluble in water.

Urea is diamine of carbonic acid.

USES OF UREA It is used as a fertilizer and

It can be used as a cattle feed.

It can be used as raw material for different products like melamine, urea formaldehyde etc.

1. First commercial urea plant was established in GERMANY in 1920.

2. In India first urea plant was established in Sindri, Dhanbaad, Bihar in 1959.

UREA PLANTTECHNOLOGY-Snam progetti

MAIN CONSULTANT- PDIL (Project and Development India Ltd.)CAPACITY-2*1310 MTPD

No. OF UNITS- Urea plant is divided into two units namely-

1. 21 UNIT- commissioned on 23rd nov,1995

2. 11 UNIT- commissioned on 14th dec,1995

UREA PROCESSRAW MATERIALS- Ammonia (liquid) + carbon- dioxide (gaseous)

The steps involved in urea production are:-

1. Urea synthesis and high pressure recovery.

2. Urea purification and low pressure recovery.

3. Urea concentration.

4. Urea Prilling.

5. Waste water treatment.

UREA SYNTHESIS AND H.P. RECOVERY:- Urea is synthesised from liquid ammonia and gaseous carbon dioxide obtained from ammonia plant at 17 kg/cm2 and 0.65 kg/cm2 respectively.

2NH3+CO2-> NH2COONH4 (Ammonium carbamate)

NH2COONH4-> NH2CONH2+H2O (Urea + water)

1. Compressor K-1 compresses CO2 coming from ammonia plant at 0.65 kg/cm2 to 157 kg/cm2 pressure.

2. Ammonia is received in V-1 and its pressure is boosted by means of pump P-5(up to 25 kg/cm2).

3. Part of ammonia is sent to M.P. absorber C-1 & remaining is sent to pump P-1 to a pressure of 240 kg/cm2g.

4. In reactor R-1 ammonia and CO2 react to form ammonium carbamate which further dehydrates to form urea and water.

5. The urea obtained here is only 33%, its concentration needs to be increased.

6. The reaction product goes to stripper E-1, where CO2

content is reduced by the stripping action of ammonia as it boils out of solution.

M.P. PURIFICATION AND RECOVERY1. E-1 bottom solution which contains around 23% NH3, 5% CO2

and 45% urea is expanded to a press. Of 17 kg/cm2 and enters the M.P. separator (MV-2) where flash gases are removed.

2. Next it goes to exchanger E-2 where most of the residual carbamate is decomposed required heat is supplied by stem coming from stripper.

3. NH3 and CO2 rich gases leaving the top of MV-2 are sent to M.P. condenser (E-7) and then the mixture goes to M.P. absorber(C-1).

4. NH3vapours leaving the top of C-1 are condensed in ammonia condenser E-9 before entering ammonia receiver (V-1).

L.P. PURIFICATION AND RECOVERY

1. The solution which now contains 62% urea leaving the bottom of M.P. decomposer (E-2) is expanded to a press. Of 3.5 kg/cm and enters L.P. separator/decomposer (MV-1/E-3).

2. The vapours leaving the top of separator are condensed in L.P. decomposer E-8.

3. The solution from E-8 is sent to carbonate solution tank (V-3), to be recycled to M.P. section by pump P-3.

SOLUTION CONCENTRATION AND PRILLING

1. Vaccum section is in two stages to get 99.7% melt for Prilling.

2. The 70% urea leaving the bottom of E-8 is sent to 1st stage Vaccum separator MV-6(operating at 0.3 ata).

3. After 1st stage 95% urea is sent to 2nd stage vaccum concentrator (E-15) and separator (MV-7) working at 0.03 ata. , heat required is met by L.P. section.

4. Urea melt is sent to Prilling spinning bucket which distributes

the urea melts in small droplets over the cross section of natural draught circular Prilling tower.

5. Cold air entering from bottom of the tower causes urea droplets solidification and is discharged from the top with urea dust.

6. Urea prills are collected at the bottom of tower and sent to bagging plant for further activity.

PROCESS CONDENSATE TREATMENT1. The water coming from vaccum system containing NH3

(5%),

CO2 (2%) and urea (1%) is collected in buffer waste water tank (V-6).

2. From there it is pumped to waste water distillation tower (C2)

3. Column C-2 is divided into two parts. From the upper part solution containing water, urea and small amount if NH3 and CO2

is to hydrolyser(R-2) where urea is decomposed into CO2 and NH3.

OFFSITE PLANTThe offsite plant meant to supply power to all utilities required for production of ammonia and urea. The plant consists of following sub plants:-

Power Generation Unit

Steam Generation Unit

D.M. Water Plant

Cooling Tower

Instrument Air Section

Effluent Treatment Plant(ETP)

Heat Recovery Steam Generator(HRSG)

Gas Turbine Generator(GTG)

Emergency Diesel Generator Set(EDG)

Ammonia Storage Unit

POWER GENERATION UNIT

The gas turbine generator is used for power generation. The gas turbine like any other heat engine is used for converting part of a fuel’s energy into useful available mechanical energy.

Gas Turbine Generator (GTG):2NOS (running & 1 standby)

Manufacturer: M/S BHEL, Hyderabad

Capacity: 26.4MW at ISO base rating

Net Output: 20.7MW

STEAM GENERATION UNITSteam required for plant is supplied by SGP .The plant consists

of a gas/naptha fired service boiler and HRSG whose specifications are as follows:-

SERVICE BOILERS

Capacity: 100 Te/Hr

Pressure: 115 kg/cm2

Temperature: 5150oC

HRSG (Heat Recovery Steam Generator)

There are 2 HRSG, each having capacity to generate 100 MTPH superheated steam at 515oC and 115 kg/cm2 pressure based on exhaust gases.

HRSG units have been supplied by M/s THERMAX BABCOCK & WILCOX, POONA.

It consists of following arrangements in the same casing:-

Supplementary firing gas burners (8 nos.)

Super heaters

Evaporators with steam drum

Economizer also a bypass duct and a vent stack.

PERFORMANCE OF HRSG:

Pressure: 115 kg/cm2at battery limit

Temperature: 515oC at battery limit

Capacity: 100 MTPH each

Steam Quality: silica<0.02ppm & total solids<0.05ppm

D.M. PLANT Demineralisation refers to the process of removal of all

minerals present in the raw water by using ion exchange resin. Demineralisation uses ion exchange as the method of purification.

Ion exchange is actually a chemical reaction in which mobile hydrated ions of a solid are exchanged for ions of like charge in solution. Thus the process is effective in removing impurities and obtaining most pure boiler feed water.

DM plant consists of provision for treatment of raw water received from tube wells and return condensate from Ammonia and urea plants. There are different sections in DM plant:-

i. Filteration section

ii. DM section

COOLING TOWERS

In the different sections during some processes heat is generated which is to be removed before the product is sent for other processes. Water is used as a cooling media for proper and efficient operation because

It is normally plentiful.

It is readily available and inexpensive.

Water can carry large amount heat per unit volume and doesn’t decompose.

During different processes cooling water gets heated up and must be cooled before it is used again. For this process cooling tower is used.

Cooling tower is one type of heat exchanger which cools hot water with air i.e., by the contact b/w hot water and air, water gets cooled.

In plant “INDUCED DRAFT CROSSED FLOW TYPE” cooling tower is used.

INSTRUMENT AIR COMPRESSOR

Instrument air is used for operating pneumatic valves and other processes. Three reciprocating compressors are used with following specifications:

Capacity: 200 mm3/hr

Pressure: 10.5 kg/cm2

(ETP) EFFLUENT TREATMENT PLANT

Different types of effluents are being generated in the plant during different processes. These can’t be disposed of unless the quality of effluents is within the permissible limits. Treated sewage water is used for the irrigation of plants developed in the surrounding for green belt.

EDG (EMERGENCY DIESEL GENERATOR)

This is a unique feature of plant, a source of power supply other than GTG. During any failure in GTG the minimum requirement for safe shutdown of the plant and GTG restart up is met by EDG. It is 2.2 MW diesel generating power at 415 KV. Provision

has been made such that in case of power fail the engine starts automatically and will supply power within 15-20 seconds.

AMMONIA STORAGE

As ammonia is produced in ammonia plant and consumed in

Urea plant. Sometimes it is not necessary that all ammonia produced is consumed therefore a storage tank of 5000 MT capacity is made to store ammonia and supply it to urea plant.

AMMONIA PLANT

The raw materials used for producing urea are ammonia and carbon dioxide. These raw materials are produced in this plant.

The commercial production of ammonia is done by Haber’s Process.

N2+3H2-> 2NH3+HEAT

Hence raw materials for ammonia are nitrogen and hydrogen. Source of nitrogen on atmosphere and hydrogen is produced from different fuels like:

NAPTHA

NATURAL GAS

WOOD

FUEL OIL

KSFL uses Natural Gas as feed stock and also as fuel in furnace. Natural gas is supplied by GAIL via HBJ pipeline from Bombay High.

TECHNOLOGY: Haldor Topsoe, Denmark

BASIC ENGINEERING: PDIL

DESIGN CAPACITY: 1529MTPD

The plant is divided different areas some important areas as follows:

11 Area: NG distribution area

12 Area: Reformer section

13 Area: CO2 removal section

14 Area: Compressor section

15 Area: Ammonia refrigeration section

16 Area: Steam n/w and utility section

AMMONIA PROCESSThe process flow diagram of ammonia is as follows:

Following are the main process steps for the manufacturing of ammonia:

DESULPHURISATON

In this process sulphur content is reduced to 0.05 ppm since it is poisonous for primary reformer catalyst.

Firstly hydrogenation is done by following reaction:

H2+S->H2S

After hydrogenation the process gas is passed through the absorption vessels where the H2S is absorbed on ZNO as follows:

ZnO+H2S->ZnS +H2O (Catalyst ZnO)

PRIMARY REFORMER

Here natural gas is reformed with steam to produce a mixture of hydrogen, carbon monoxide and methane.

The steam reforming of hydrocarbons can be described by following reactions:

CH4 + 2H2O -> 4H2 – HEAT (catalyst Ni)

CO2 + H2 -> CO + H2O – HEAT

SECONDARY REFORMER

It is to reform the primary reformer exit and to add nitrogen to the process gas. It is done by mixing process air to the primary reformer exit gases. Now the outlet contains H2, N2, CO, CO2 and CH4 (0.3%).

WASTE HEAT BOILER

The temperature of secondary reformer exit is very high (>11000C). This temperature is used to produce H.P. steam which is utilised as process steam and as a driving force for major rotator equipments.

CO2 REMOVAL

GV (giammarco vetrocoke) solution is used to absorb CO2 from the process gas thus reducing CO2 content from 17.72% to 0.05% in the gas mixture in CO2 absorber. GV solution rich in CO2

is regenerated in HP & LP regenerators by giving heat. The CO2 is sent to urea plant.

METHANATION

Oxides being harmful for converter catalyst, CO and CO2 are converted into methane.

CO + 3H2 <-> CH4 + H2O + HEAT (catalyst Ni)

CO2 + 4H2 <-> CH4 + 2H2O + HEAT

The exit synthesis gas contains mainly of hydrogen and nitrogen.

SYNTHESIS GAS COMPRESSION

The mixture is compressed to 220 kg/cm2 in synthesis gas compressor for the synthesis of nitrogen and hydrogen.

AMMONIA SYNTHESIS

Conversion of this gas mixture into ammonia takes place in TOPSOE-S200 radial flow converter according to the following reaction:

3H2 + N2 <-> 2NH3 + HEAT

REFRIGERATION SYSTEM

Gas mixture containing ammonia is cooled down to separate liquid ammonia from the gases by providing ammonia refrigeration. Separated liquid ammonia is sent to urea plant at 120C. In case urea plant is not in operation, product ammonia is sent to ammonia storage.

AMMONIA RECOVERY SECTION

This section consists of an absorber operating at 14.5 kg/cm2, a distillation column operating at 19 kg/cm2g. Purge gas enters to the absorber where ammonia is absorbed in DM water. The ammonia free gas is used as fuel in primary reformer. Ammonia rich DM water is pumped to distillation column where ammonia is stripped, condensed and sent to storage.

PURGE GAS RECVOERY

This section consists of a scrubber operating at 120 kg/cm2, prism separators operating at 24 kg/cm2. Scrubber absorbs ammonia, the ammonia free gas is fed to prism separator where hydrogen is permeated through separator membrane and is fed to syn gas compressor suction. Non permeated gas is used as fuel in primary reformer.

AMMONIA CONTROL ROOM SYSTEMS

DISTRIBUTED CONTROL SYSTEM (DCS): YOKOGAWA CS3000

EMERGENCY SHUTDOWN SYSTEM (ESD): YOKOGAWA prosafe

VIBRATION MONITORING SYSTEM (VMS): BENTLY NEVADA 35000 SERIES

BURNER MANAGMENT SYSTEM (BMS)

WOODWARD GOVERNING SYSTEM

INSTRUMENTATION

Since the industrial processes are complicated, it is not possible to control them without instrumentation. Thus primary objective of instrumentation is to control plant processes rationally and safely.

The term instrumentation refers to the design and installation of a measuring and controlling instrument system for an industrial process.

At the design and construction stage of the plant rationally designed instrumentation system affects the capacities of plant equipments and costs.

At the running stage, good instrumentation system provides effective utilisation of raw materials ensures highest and uniform quality of products and reduces running costs.

In addition it greatly economises manpower. It also releases workers from routine toils. It also safeguards the plant against hazards.

To plan an effective instrumentation system it is essential to study in detail and consider following points:

Operating principle and capacity

Characteristics of instruments

Standard methods for start and stop of operation

Actions to be taken in case of strategy.

The characteristics of instruments can be divided into:

Static characteristics

2. Dynamic characteristics

STATIC CHARACTERISTICS:

These are those characteristics that must be considered when the system or instrument is used to measure a condition that is not varying with time. The static characteristics consist of following:

Accuracy

Sensitivity

Reproducibility

Drift

Dead zone

DYNAMIC CHARACTERISTICS:

These characteristics are considered when measuring conditions are varying with time.

MEASURING INSTRUMENTSThere are different instruments for measuring different process parameters (pressure, temperature, flow and level). There are instruments in field area for local indication and then transmitting the measured signal to the control room for controlling process.

There are four main equipments for measuring and maintaining the process parameters:

GAUGES

TRANSMITTERS

SIWTCHES

CONTROL VALVES

PRESSURE: Pressure= Force/Area

There are different types of pressure namely:

Gauge pressure

Vaccum pressure

Atmospheric pressure

Absolute pressure

Different units for pressure measurement are:

Kg/cm2

mmH2O

mmHg

inH2O

inHg

psi

KPa

The relation between these units can be stated as:

1 kg/cm2=1000 mmH2O

=14.27 psi

=98.02 KPa

=393.67 inH2O

MEASUREMENT OF PRESSURE:

Instruments used in the plant for local pressure measurement are bourdon tubes, diaphragms gauges and bellows. Other than this transmitter is there for transmitting pressure signal to the control room in form of current signal (4-20 mA).

BOURDON TUBE PRESSURE GAUGE:

It is the most frequently used pressure gauges because of its simplicity. There are different types of bourdon tubes used namely:

1. C-type

2. Spiral

3. Helical etc

Construction

As the name suggests C-type bourdon tube consists of a alphabet C shaped long thin walled cylinder made of materials such as phosphor, bronze, steel and beryllium copper. The tube is fixed to one end from here the pressure to be measured is exerted, other end is free and pointer is attached to this free end.

Operation

When pressure is applied from the fixed end, the free end deflects due this pressure; hence the pointer attached through suitable linkage also deflects indicating pressure on the calibrated scale or this pressure may be transduced to an electrical signal by one means or another.

DIAPHRAGM TRANSDUCER GAUGES:

A diaphragm is a thin circular sheet made mainly of rubber like neoprene. It is clamped firmly around its edges. The diaphragms

can be in the form of flat corrugated plates and the choice depends on the value of pressure and amount of deflection required. There can be different types of diaphragm elements namely:

METALLIC DIAPHRAGMS: they consist of a thin flexible diaphragm made of metals like brass or bronze.

NON-METALLIC DIAPHRAGM: It is more difficult to measure pressure below atmospheric pressure because changes are

Small. Hence diaphragms are made of rubbers like neoprene etc. for the measurement of such small values of pressure.

The diaphragm gets deflection in accordance with the pressure differential across the sides, deflection being towards the low pressure side.

For low pressure or Vaccum measurement manometers, bourdon gauges or diaphragm gauges cannot be used effectively. For such values of pressure measurement Mc. Leod gauge, Knudsen gauge, thermal conductivity gauge.

CAPACITIVE PRESSURE TRANSDUCER:

The principle of operation of capacitive pressure transducers is based upon the capacitance equation of the parallel plate capacitor.

C= (K*A)/D

Where, C, K= capacitance, dielectric constant

A,D= area of the plate, distance b/w the two plates.

TEMPERATURE: Temperature is defined as the degree of hotness or coldness as referred to a specific scale of temperature measurement.

There are different temperature scales namely:

Kelvin scale(K)

Celsius scale(0C)

MEASUREMENT OF TEMPERATURE

There are different methods for temperature measurement. Some of them are as follows:

BIMETALLIC TEMPERATURE GAUGES:

Construction :

Two metal strips of metal A and B having different thermal expansion coefficient αA and αB at the same temperature are firmly bonded together. B metal is generally made of invar, nickel steel with a nearly zero expansion coefficient; expansion coefficient of A is comparatively greater.

A wide range of configurations have been made for different applications. Mainly spiral and helical are used.

Operation:

Since the two metal strips joined together are having different expansion coefficient, a temperature change causes differential expansion and the strip deflects into a circular arc and if a pointer is attached, it will also deflect.

The accuracy of bimetallic element varies greatly depending on the requirement of the application. The normal working range is from -1000 to10000F

THERMOCOUPLES

Thermocouples have been the choice of instrumentation engineers for many years.

Construction:

Two different material wires A and B are connected to form in a circuit with one junction at T1 temperature and other at T2. The circuit formed is a closed one. A voltmeter can also be connected to detect the emf produced

Working:

Thermocouples work on two basic principles namely Seeback and Peltier effects.

Seeback effect states that when the two junctions are at differential temperature, the colder junction is the reference junction and the hotter junction is the measuring junction. Due to this temperature difference and emf is detected in the circuit by the voltmeter.

Peltier effect states that if one of the junctions is heated and other is cooled and if a current is allowed to flow in the circuit, the amount of temperature rise in one junction and the amount

of temperature fall in the other will depend on the current intensity and direction. i.e.

Hf = πI where Hf =heat across the circuit

π = deflection coefficient

There are different types of thermocouples used namely:

J type- Iron and Constantan

K type- Chromel and Alumel

T type- Copper and Constantan etc.

Out of which K type is generally used with measurement range

-9000C to 13750C

RTD (RESISTANCE TEMPERATURE DETECTOR):

Electrical resistance of some materials changes with temperature, such materials can be divided into two classes i.e., Conductors and semi conductors. The conducting materials are called RTD and the semiconducting are known as thermistors.

The variation of resistance with temperature is given by the relation:

R = R0 (1+a1T+a2T+........anT)

Where R0 is the resistance at temperature T=0.

They are mainly made of platinum, nickel and copper. Out of which platinum RTDs are mostly used.

Construction :

The platinum wire usually 0.025 mm OD or less is wound into a coil and inserted into a multicome high purity ceramic tube or

may be directly wound on the outside of a ceramic tube. The winding is completely embedded and fused within or on the ceramic tube utilizing extremely granular powder.

The intimate contact between the platinum winding and the ceramic encapsulation permits rapid speed of response with the thermal conductivity of ceramic adequate for heat transmission.

Following are the three RTDs:

Platinum RTDs

Thin – Film Platinum RTDs

Wire wound Platinum RTDs

Range of measurement of platinum RTDs is from -300 to 100F.

MEASUREMENT OF FLOWThere are numerous means of measuring the flow rate of fluids, including liquids, slurries, gas and vapours as these materials transit through pipelines, conduits and open channels. Due to the differences in the properties of industrial fluids, numerous flow measurement methods have been developed over the years. Some flow meters determine mass directly, but the majority of systems measure some quantitative dimensions from which the flow rate can be inferred.

CONSTANT AREA VARIABLE PRESSURE DROP METER:

Widely used flow metering principle involves placing a fixed area flow restriction of some type in the pipe or duct carrying the fluid. This flow restriction causes a pressure drop by means of a suitable differential pressure pick up allows flow rate measurement.

Commonly used restriction element is ORIFICE. There are different types of orifice namely:

Eccentric

Concentric

Segmental

Due to its simplicity and low cost it is most widely employed flow metering element. The orifice has the largest permanent pressure loss;

this is one of its disadvantages since it represents a power loss.

Orifice discharge coefficient is quite sensitive to the conduction of upstream edge of the hole.

If one dimensional flow of a fluid is assumed then volume flow rate Q1 is given as:

Q1 = {Cd A2/Г (1-(A2/A1)2)}*{Г (2(P1-P2)/ρ}

Where A1= pipe cross section area

A2= orifice cross section area

ρ= fluid mass density

Cd= discharge coefficient

P1, P2= pressure

Other than this other flow measuring practical devices are FLOW NOZZLE, VENTURI TUBE, DALL FLOW TUBE etc.

ROTAMETER:

A rotameters consists of a vertical tube with tapered bore in which a float held in vertical position corresponding to each

flow through the tube. For a given flow rate the float remains stationary since the vertical forces of differential pressure

Gravity, viscosity and buoyancy are balanced. This balance is self maintaining since the meter flow area or the annular area between the float and tube varies continuously with vertical displacement. The tapered tube used in rotameters provides variable area.

Fluid enters from the bottom of the tube and exerts upward force on the float, hence the float displaces from its position. The float position is the output of the meter.

Accuracy of rotameters is typically 2% full scale with repeatability of about 0.25% of full scale reading.

MEASUREMENT OF LEVELDifferent methods are in use for level measurement and transmission. Following are some of them:

Capacitance type

Differential pressure type

Radiation level detector

Capacitance type level detector:

The capacitor with concentric cylindrical electrodes can be used to measure level of liquids that are non-conducting or insulating.

The capacitance due to the columns of liquid and its vapour is given by:

C= 2πϵ0{(ϵ1h1+ϵ2h2)/[log(r2/r1)]}

Where, ϵ1= dielectric constant of fluid

ϵ2= dielectric constant of remaining space

h1= height of fluid

h2= height of remaining space

This is the basic capacitance type level indicator:

A typical capacitance switch is used practically; normally the unit attached to the tank gives the output of 4 to 20mA range for connecting to digital microprocessor based equipment.

Diaphragm level detector:

All diaphragm detectors operate on the simple principle of detecting the forces exerted by the process material against diaphragm.

Differential pressure type level detector:

Liquid level can be measured by measuring a DP caused by the

weight balanced against a reference. This method of level detection is often referred as hydrostatic tank gauging especially in the bulk liquid industries.

Differential pressure can be detected by sensing two pressures separately and taking the difference to obtain liquid level.

The extended diaphragm version is designed to both directly to the vessel nozzle the protrusion can be sized to fill the space in the nozzle, placing the diaphragm flush with or slightly inside the vessel wall.

This design eliminates dead end cavities and is used specially on material that can freeze at high temperature.

Radiation level sensors:

The principle of measurement is based in irradiation method. It utilises the physical law of absorption of radiation passing through the matter. Resulting effect is the ratio of I and I0 i.e. attenuated radiation and un-attenuated radiation respectively.

Radioactive source used is 60Co as it has relatively high energy of 1.17MeV and half life of 5.27 years.

Radioactive substance is tightly welded into a stainless steel capsule, so that it can’t leak out.

TRANSMITTERS

Above explained were gauges. Now the signal measured by these gauges needs to be sent to the control room for analysing and controlling purpose.

It consists of two functional units namely:

Primary unit

Secondary unit

Primary unit:

This unit includes the process interface and sensor. The process fluid exerts pressure into the sensing unit i.e. the diaphragm. As the measuring diaphragm deflects in response to input pressure changes, it produces vibrations in the gap between the magnetic disk and core of the coil mounted rigidly into primary body. As a result the inductance of coil changes, which is compared to that of reference inductor. The two inductance values are combined to provide a proportionally standard signal.

Secondary unit:

Here a microprocessor compares precisely primary output compensating the combined effect of sensor non linearity and temperature changes.

CONTROL VALVESControl valves manipulate a flowing fluid such as gas, steam, water or chemical component to compensate for the load disturbance and keep the regulated process variable as close as possible to the desired set point.

The control valve assembly typically consist of:

Valve body

Internal trim part

Actuator

Positioner

Transducer

Pressure supply

Regulator

Limit switch

The functional or block diagram of control valve is as follows:

Output signal from control room is sent to the I/P converter. Output of I/P converter goes to the Positioner of the valve where it works as signal for relay. Then according to the percentage signal relay is operated. Air goes to the actuator through relay where the diaphragm is displaced hence valve opens.

I/P SIGNAL CONVERTER

The electro-pneumatic signal converter is used as a linking component between electric and pneumatic system. It converts standard electric signals (4-20mA) respectively into standard pneumatic signal 0.2-1Bar.

Due to its innovative construction, principle based on fixed coil and a low mass moving permanent magnet the I/P signal converter is highly resistant to shocks and vibration.

Input current signal through coil armature arrangement acts on a beam. The flapper positions itself against a nozzle creating a back pressure which provides feedback via a resistance orifice to position the flapper accurately. The result is a pneumatic signal proportional to the current.

DISTRIBUTED CONTROL SYSTEM

A DCS is a microprocessor based control and acquisition system comprising of multiple modules over a network. The system functions can be geographically and functionally distributed.

Operator interface to a system is through a console with CRT display and keyboards.

Typical DCS are as follows:

PID CONTROL

DISCRETE CONTROL

ADVANCED CONTROL

GRAPHICAL AND SCHEMATIC DISPLAY

COMMUNICATION WITH OTHER SYSTEMS AND SUB SYSTEMS

DATA AQUISITION

REPORT GENERATION

A DCS system has following properties:

1. Measurement, control and communication are performed by groups of modules that are distributed in function and location.

2. The control of the process by the plant operator is performed in centralized control room.

3. Local operating control stations may be scattered over the plant.

4. A communication channel runs through the plant and connects to all parts of the DCS.

5. A distributed control system can start small and expand as need requires and circumstances permit.

6. It provides improved control of the plant by the plant operator.

7. It provides greater flexibility to the control system with easy changes of control plan.

In KSFL control room DCS used is of YOKOGAWA.

SAFETYThe plant has a highly structured housekeeping scheme, a fire and safety department and an excellent accident-prevention program. Highest priority is accorded to maintain high safety standards. Apart from holding regular fire drills, periodical emergency mock drills are conducted onsite. Safety audits are regularly undertaken by external experts and their recommendations are meticulously implemented. Gas monitoring and detection systems have been installed at toxic gas handling areas. Approved personal protective equipment of international standards is utilized for safe working. The Plant Safety committee and the Central Safety committee are very active. There is a widely publicized “Safety, Health & Environment Policy” being diligently followed. 

ENVIROMEMTAL POLICY (ISO-14001-2004)

KRIBHCO SHYAM FERTILIZERS Ltd. Is committed to continually improve its environmental performance and to prevent pollution due to its activities associated with manufacturing and supply of urea. Company is also committed to comply with relevant environmental legislations and regulations.

OUR COMMITMENT SHALL BE FULLFILLED BY:

1. CONSERVATION OF NATURAL RESOURCES

2. REDUCING THE SPILLAGES AND EMISSIONS TO AIR

3. MANAGING THE WASTE GENERATED

4. MAINTAINING THE QUALITY OF TREATED EFFLUENT AND MINIMISING THE DISCHARGE QUANTITY.

WE SHALL INVOLVE ALL EMPOLYEES IN CREATING CLEAN AND GREEN KSFL.

CONCLUSION KSFL project is one of the leading fertilizer producers in U.P.

having capacity to produce around 2600 MTPD of urea.

KSFL is environmental friendly following the norms of Uttar Pradesh Pollution Control Board (UPCB).

The working principle is based on modern techniques which have provision for recycling the unutilised elements and by products.

KSFL provides an encouragement to the budding technocrats by providing a brilliant platform to enhance their skills.

KSFL is producing its own power which is supplied to the township also.

IN ADDITION RECENT FOCUS IS ON THE DEVELPOMENT OF NEEM COATED UREA.

THANK YOU