A

Project report on

Measurements and Control At

HINDUSTAN ZINC LIMITED,

DARIBA, RAJSAMAND, RAJASTHAN.

Submitted in partial fulfillment of requirements for the degree of

BACHELOR OF TECHNOLOGY

by

Akhil Sodani

ID-11EJCEC301

Under the supervision of

Mr. H.K.Gupta

Manager, Instrumentation

Hindustan Zinc Ltd., Dariba

           

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

JAIPUR ENGINEERING COLLEGE AND RESEARCH CENTRE, JAIPUR

ACKNOWLEDGEMENT

It’s a great pleasure to present this report of summer training in HINDUSTAN ZINC LIMITED

(DARIBA) in partial fulfillment of B-TECH Program under Jaipur Engineering College and

Research Centre, affiliated to Rajasthan Technical University, Kota. At the outset, I would like to

express my immense gratitude to my training guide Mr. H.K.Gupta. For guiding me right from the

inception till the successful completion of the training.

I am falling short of words for expressing my feelings of gratitude towards him for extending his

valuable guidance about technology, equipments and support for literature, critical reviews of

project and the report and above all the moral support he had provided me with all stages of this

training.

I would also like to thank my friends and all my group members for their help and cooperation

throughout the training.

Akhil Sodani

(IV year, ECE Dept)

(JECRC, Jaipur)

PREFACE

The summer training of a engineering student pays an important role in developing has as a well-

groomed professional. It allows a student to give theoretical concepts a practical stand in the

field of application. It gives the candidate an idea of dynamic & versatile professional world as

well as exposure to the intricacies and complexities of corporate world.

Doing the summer training at HINDUSTAN ZINC LIMITED was a great experience. An

opening experience to the concepts of engineering which helped me lot in understanding the

concepts that are applied in the organization. This organization since its inception has progressed

a lot & is walking on the guidelines of success .As the organization is marching with the

tenacious speed towards the horizon.

In a period of 45 days exposure to the corporate environment, I got a learning of organizational

structure, its protocols, etc. Real learning places its worth only when it gives sweet fruits in

future. Summer training is one way to learn at work. I enjoyed the interesting experience and

every part of it.

INDEX

1. Introduction

2. History

3. Market strength

4. About Hindustan Zinc Limited, Dariba

5. Zinc Plant

Roasting Plant

Leaching Plant

Cell House

6. Instrumentation

Temperature Detectors

Pressure Transducers

Level Detectors

Flow Detectors

7. Level Transmitter

Principle of operation

Specifications of level transmitter

Lab Results

8. Industrial Automation

PLC

DCS

SCADA

9. Conclusion

10. References

INTRODUCTION

India is a country of large dimension. It spreads over a geographical area of 3.29 million Square

Kilometers, which is about 2.5% of the globe and makes the country the seventh largest in the

world. India is Asia’s third and worlds eleventh largest economy.

India produces as many as 84 minerals compromising 4 fuels, 11 metallic, and 49 non-metallic

industrial and 20 miner minerals. Their aggregate production in 2004-2005 as about 600 million

tones, contribution by over 3,100 mines (reporting mines) producing coal, lignite, limestone, iron

ore, bauxite, cooper lead, zinc etc. the aggregate value of mineral production in 2004-2005 was

more than Rs. 450 billion ( app. $10 billion ).

The minerals policy opened the gates of Indian minerals industry to domestics and foreign

investment, much of which was earlier reserved for the public sector. It aims to boost the

country’s exploration and mining efforts and render the mineral industry more competitive.

There are following player’s deals in mineral and mining sector-

HINDUSTAN ZINC LIMITED

HINDUSTAN COPPER LIMITED

INDIAN ALUMINUM COMPANY

STERLITE INDUSTRIES LIMITED

HINDUSTAN ALUMINUM COMPANY

HISTORY

Hindustan Zinc Limited was incorporated from the erstwhile Metal Corporation of India on 10

January 1966 as a Public Sector Undertaking.

In April 2002, Sterlite Opportunities and Ventures Limited (SOVL) made an open offer for

acquisition of shares of the company; consequent to the disinvestment of Government of India's

(GOI) stake of 26% including management control to SOVL and acquired additional 20% of

shares from public, pursuant to the SEBI Regulations 1997. In August 2003, SOVL acquired

additional shares to the extent of 18.92% of the paid up capital from GOI in exercise of "call

option" clause in the share holder's agreement between GOI and SOVL.

With the above additional acquisition, SOVL's stake in the company has gone up to 64.92%.

Thus GOI's stake in the company now stands at 29.54%.

MARKET STRENGTH

Our sustainable strategy aligns with the overall business strategy and reflects a clear

understanding of the needs and expectations of our key stakeholders.

The key drivers of our approach are: proactive engagement with our stakeholders; attracting and

retaining the best talent; our provision of a safe and healthy working environment; focus on

using environmentally friendly technologies and drive to conserve natural resources. We have a

set of ambitious targets to optimize our natural resources usage. Water and energy conservation

performance has been promising and has exceeded our targets in some instances.

Our people are our valued asset and our vision is to build a flexible, agile and flat organization

with world-class capabilities and a high-performance culture.

We are committed to achieving the best practices in health safety and environment at all of our

sites. Our systems are well established and are regularly reviewed and monitored taking into

account our own experiences and industry best practices. We believe we have a responsibility to

engage with the communities in which we operate and to foster their social and economic

development. These principles are embedded across the organization and are a key element of

our employee training, development and performance at all levels.

Through this strategy we are dedicated to meeting our sustainable development challenges. We

have a well defined sustainable development framework that comprises of governance structures

and policies, that act as pillars and supports our sustainable development endeavor.

ABOUT HINDUSTAN ZINC LTD. DARIBA

Hindustan Zinc Limited (HZL) is an integrated mining and resources producer

of zinc, lead, silver and cadmium. It is a subsidiary of Vedanta Resources PLC. HZL is the

world's second largest zinc production.

HZL operates the world's third largest open-pit mine, and World's largest Zinc Mine in Rampura,

Agucha in Rajasthan. Other mines with HZL are located in Sindesar Khurd, Rajpura, Dariba,

Kayar and Zawar, all in Rajasthan. HZL is also the world's lowest cost zinc producer. HZL

operates Zinc and Lead smelters and refineries at Chanderiya (Chittorgarh), Debari (Udaipur) &

Dariba (Rajsamand) in Rajasthan and at Vishakhapatnam in Andhra Pradesh.

Hindustan Zinc Limited was incorporated from the erstwhile Metal Corporation of India on 10th

January 1966 as a Public Sector Undertaking. In April 2002, Sterlite Industries (India) Limited

made an open offer for acquisition of shares of the company consequent to the disinvestment of

Government of India’s stake (26%) including management control to Sterlite and pursuant to the

regulations of SEBI Regulations 1997 acquired additional 20% of shares from public.

HZL is India’s only integrated Zinc Company, operating from mine to finished metal and

supplied around 73% of India’s zinc requirements in 2005-06. At the base of the company is the

Rampura Agucha mine with its low cost and consistently high grade ore. The Smelter complex in

Dariba was started in 2009.

Dariba smelter Complex (DSC) is divided as following

1. Zinc Plant

2. Lead Plant

3. Captive Power Plant(CPP)

ZINC PLANT

Zinc Smelter Complex (Zinc Plant) is further divided into three areas:

• Roaster

• Leaching

• Cell House

ROASTING PLANT

In Roasting Plant, oxidation of zinc sulfide concentrates at high temperatures into an impure zinc

oxide, called "Calcine". The chemical reactions taking place during the process are:

Approximately 90% of zinc in concentrates is oxidized to zinc oxide, but at the roasting

temperatures around 10% of the zinc reacts with the iron impurities of the zinc sulfide

concentrates to form zinc ferrite. A byproduct of roasting is sulfur dioxide, which is further

processed into sulfuric acid. Zinc oxide obtained is then sent in leaching plant for further

processing.

Firstly, zinc sulphide after ore concentration process is sent to furnace .There at 920-950 degree

temperature zinc sulphide combustion takes place producing calcine. Further oxidation of SO2

maintains the temperature range, and then SO3 is sent to acid plant for production of sulphuric

acid. HZL, Dariba has 2 roaster units R4 and R5. Zinc Sulphide Concentrate is introduced

directly into the roaster and roasted in a turbulent layer, largely consisting of roasted material

especially Zinc Oxide (ZnO). This layer has been heated to ignition temperature by thee

preheating device. The desired reaction is maintained by an exothermic reaction of Sulfide

Concentrate and air in the turbulent layer.

The surplus reaction heat is taken out of the roaster bed by cooling elements installed in the

turbulent layer in the form of evaporator heating surfaces connected to the Waste Heat Boiler.

The waste heat is further utilized to generate electricity of about 9.6MW which is used in the

plant.

Roaster part of plant also divided as follows:

1. Raw Material Handling (RMH)

2. Roaster

3. Waste Heat Recovery Boiler (WHRB)

4. Hot Gas Precipitator (HGP)

5. Gas Cleaning Plant (GCP)

6. Sulphuric Acid Plant (SAP)

7. Acid Loading Plant

ACID PLANT

The utilization of sulphur containing gases after zinc concentrate roasting is carried out at the

sulphuric acid plant resulting in marketable sulphuric acid.

For the treatment of Sulphur Dioxide (SO2) in the roasting off-gas, by passing through the Gas

Drying Tower, the Sulphur Dioxide (SO2), cooled and saturated with water vapor, comes in

direct contact with concentrated acid. Sulfuric Acid (H2SO4) of this concentration is very

hygroscopic (absorbs waters) and the gas is practically free from water vapor after leaving the

Drying Tower.

After the Drying Tower, the Sulphur Dioxide (SO2) has to be converted into Sulfur Trioxide

(SO3) to allow the production of Sulphuric Acid (H2SO4) according to the following reactions:

SO2 + 1/2 O2 → SO3

SO3 + H20 → H2SO4

Gas coming out of hot gas precipitator has 7-8%of SO2 at 330 degree Celsius.SO2 gas is passed

through scrubbing tower, which has sedimentation tank and SO2 stripper & wet gas precipitator.

In presence of V2O5, oleum is formed which further gives H2SO4.

LEACHING PLANT

The calcine is first leached in a neutral or slightly acidic solution (of sulphuric acid) in order to

leach the zinc out of the zinc oxide. The remaining calcine is then leached in strong sulfuric acid

to leach the rest of the zinc out of the zinc oxide and zinc ferrite. The result of this process is a

solid and a liquid; the liquid contains the zinc and is often called leach product. There is also

iron in the leach product from the strong acid leach, which is removed in an intermediate step, in

the form of jarosite. Jarosite is a waste therefore it is sent to Effluent treatment plant. There is

still cadmium, copper, arsenic, antimony, cobalt, germanium and  nickel in the leach product.

Therefore it needs to be purified.

The basic leaching chemical formula that drives this process is:

ZnO +H2SO4→ZnSO4 + H2O

MeO + H2SO4→MeSO4+ H2O

Me→ Metals other than Zinc present in concentration

Leaching Area is distributed in following buildings:

1. Weak acid leaching building

2. Jarosite precipitation building

3. Purification building

4. Gypsum removal building

PURIFICATION

It uses zinc dust, Potassium Antimony Tartarate (PAT) and steam to remove copper, cadmium,

cobalt, and nickel, which would interfere with the electrolysis process. After purification,

concentrations of these impurities are limited to less than 0.02 milligram per liter Purification is

usually conducted in large agitated tanks called Pachukas. The process takes place at

temperatures ranging from 40 to 85 °C (104 to 185 °F). The zinc sulfate solution must be very

pure for electrolysis to be at all efficient. Impurities can change the decomposition voltage

enough to where the electrolysis cell produces largely hydrogen gas rather than zinc metal.

That’s the reason zinc sulphide is passed through various thickeners and then hot filter beds

where the zinc sulphate goes with the solution as it is soluble. This ZnSO4 solution has pH of 5

which is then sent to electrolysis process.

Zinc calcine, leach solutions and cell house acid are mixed in 11 agitated tanks which are

controlled to varied pH, from 2 to 5, by additions of cell house acid or calcine. Continuous pH

monitoring is facilitated by submerged pH cells in controlled tanks.

After leaching, the acid leach slurry is distributed to four 24-m thickeners where the leach

residues are separated from the clear zinc sulphate solution. The residues are filtered and washed

before being pumped to the Lead Smelter for further processing to recover zinc and other metals.

These recovered metals are recycled as a fume to the zinc circuit through the Oxide Leach Plant.

Clear zinc sulphate solution flows continuously from the thickeners to the zinc dust purification

circuit. Solution flow rate from this circuit is approximately 450 m/h. An increase in acid

concentration from 3 to 4% resulted in a 5% increase in recovery. The higher the concentration

of the acid the better the dissolution of the zinc, so zinc is recovered mostly.

CELL HOUSE

Zinc is extracted from the purified zinc sulfate solution by electro winning, which is a

specialized form of electrolysis. The process works by passing an electric current through the

solution in a series of cells. This causes the zinc to deposit on the cathodes (aluminum sheets)

and oxygen to form at the anodes. Every 24 to 48 hours, each cell is shut down, the zinc-coated

cathodes are removed and rinsed, and the zinc is mechanically stripped from the aluminum

plates.

A portion of the electrical energy is converted into heat, which increases the temperature of the

electrolyte. A portion of the electrolyte is continuously circulated through the cooling towers

both to cool and concentrate the electrolyte through evaporation of water. The cooled and

concentrated electrolyte is then recycled to the cells. This process accounts for approximately

one-third of all the energy usage when smelting zinc.

Zinc contained in the purified Zinc Sulphate (ZnSO4) is recovered as metal in the Electrolysis

Plant. Zinc Electro-Winning is a method of depositing Zinc Metal (Zn) on the surface of

Aluminum Sheet (Al) in cell by passing electric current through the cell. The thickness of Zinc

Plating depends on the time spent in the electrolysis cell, the amount of current, and the chemical

composition of the cell.

The electrolysis cells are arranged in one electrical circuit of two rows of cells each. The circuit

is serviced by two transformer rectifiers that are connected in parallel by Aluminum (Al) and

Copper (Cu) bush bars. The cells are connected in series while the Anode/Cathode System in

each cell is in parallel.

Principle electrolysis reaction:

ZnSO4 + electricity →Zn++ + SO4 --

Zn++ + 2e- →Zn

INSTRUMENTATION

Temperature Detectors

The hotness or coldness of a piece of plastic, wood, metal, or other material depends upon the

molecular activity of the material. Kinetic energy is a measure of the activity of the atoms which

make up the molecules of any material. Therefore, temperature is a measure of the kinetic energy

of the material in question.

Resistance temperature detectors (RTD)

The resistance of an RTD varies directly with temperature:

- As temperature increases, resistance increases.

- As temperature decreases, resistance decreases.

RTDs are constructed using a fine, pure, metallic, spring-like wire surrounded by an insulator

and enclosed in a metal sheath.

A change in temperature will cause an RTD to heat or cool, producing a proportional change in

resistance. The change in resistance is measured by a precision device that is calibrated to give

the proper temperature reading.

Thermocouples

Thermocouples will cause an electric current to flow in the attached circuit when subjected to

changes in temperature .The amount of current that will be produced is dependent on the

temperature difference between the measurement and reference junction; the characteristics of

the two metals used; and the characteristics of the attached circuit.

Heating the measuring junction of the thermocouple produces a voltage which is greater than the

voltage across the reference junction. The difference between the two voltages is proportional to

the difference in temperature and can be measured on the voltmeter (in mill volts). For ease of

operator use, some voltmeters are set up to read out directly in temperature through use of

electronic circuitry.

Pressure Transducers

Bellows-Type Detectors

The need for a pressure sensing element that was extremely sensitive to low pressures and

provided power for activating recording and indicating mechanisms resulted in the development

of the metallic bellows pressure sensing element. The metallic bellows is most accurate when

measuring pressures from 0.5 to 75 psig. However, when used in conjunction with a heavy range

spring, some bellows can be used to measure pressures of over 1000 psig.

Basic Metallic Bellows

The bourdon tube consists of a thin-walled tube that is flattened diametrically on opposite sides

to produce a cross-sectional area elliptical in shape, having two long flat sides and two short

round sides. The tube is bent lengthwise into an arc of a circle of 270 to 300 degrees. Pressure

applied to the inside of the tube causes distention of the flat sections and tends to restore its

original round cross-section. This change in cross-section causes the tube to straighten slightly.

Since the tube is permanently fastened at one end, the tip of the tube traces a curve that is the

result of the change in angular position with respect to the center. Within limits, the movement of

the tip of the tube can then be used to position a pointer or to develop an equivalent electrical

signal to indicate value of the applied internal pressure.

Level Detectors

Gauge Glass

Gauge glasses made from tubular glass or plastic are used for service up to 450 psig and 400°F.

If it is desired to measure the level of a vessel at higher temperatures and pressures, a different

type of gauge glass is used. The type of gauge glass utilized in this instance has a body made of

metal with a heavy glass or quartz section for visual observation of the liquid level. The glass

section is usually flat to provide strength and safety.

Gauge Glass

Ball Float

The operation of the ball float is simple. The ball floats on top of the liquid in the tank. If the

liquid level changes, the float will follow and change the position of the pointer attached to the

rotating shaft.

Ball Float Level Mechanism

Flow Detectors

Head Flow Meter

Head flow meters operate on the principle of placing a restriction in the line to cause a

differential pressure head. The differential pressure, which is caused by the head, is measured

and converted to a flow measurement. Industrial applications of head flow meters incorporate a

pneumatic or electrical transmitting system for remote readout of flow rate. Generally, the

indicating instrument extracts the square root of the differential pressure and displays the flow

rate on a linear indicator.

Electromagnetic flow meter

The electromagnetic flow meter is similar in principle to the generator. The rotor of the generator

is replaced by a pipe placed between the poles of a magnet so that the flow of the fluid in the

pipe is normal to the magnetic field. As the fluid flows through this magnetic field, an

electromotive force is induced in it that will be mutually normal (Perpendicular) to both the

magnetic field and the motion of the fluid. This electromotive force may be measured with the

aid of electrodes attached to the pipe and connected to a galvanometer or an equivalent. For a

given magnetic field, the induced voltage will be proportional to the average velocity of the

fluid. However, the fluid should have some degree of electrical conductivity.

LEVEL TRANSMITTER

Level measurement technology based on the non-contacting ultrasonic principle is especially

suited for applications where, for any reason, no physical contact can be established to the

surface of the material to be measured.

Such reasons may include corrosive attack by the process medium against the measuring device

material (acids), possible contamination (sewage) or particles of the process medium adhering to

the measuring device(adhesive materials).

Principle of Operation

The ultrasonic level metering technology is based on the principle of measuring the time required

for the ultrasound pulses to make a round trip from the sensor to the level to be measured and

back. The sensor emits an ultrasonic pulse train and receives the echoes reflected. The intelligent

electronic device processes the received signal by selecting the echo reflected by the surface and

calculates from the time of flight the distance between the sensor and the surface which

constitutes the basis of all output signals of the EchoTREK.

The beam angle for level transmitter is 5° to 7°.

Ultrasonic Level Transmitter

Data logger of Level Transmitter

The logger of the device can store 12288 events. The registry is in a non-volatile (FLASH)

memory, so the registry will retain its contents even in case of a power failure. The on-board

clock of the device is protected against short power-outs, and keeps working for at least 15 days

after the device is switched off. The battery protecting the clock needs at least two hours to be

recharged.

The logger operates in two basic ways.

Linear logging, where by an entry is logged after every time period is configured.

Event-controlled logging, where by an entry is logged after an internal event occurs or condition

is fulfilled.

Specifications of EchoTREK SBB-49N-1 level transmitter:

Power supply: 85.255V AC

Output: 4 to 20mA

Ambient temperature: -25 °C to +75°C

Medium temperature: -30°C to +90°C

This level transmitter can be calibrated to output 4mA to 0% level of tank and 20mA to when

100% tank is filled and all corresponding values are calculated according to level of tank.

Lab results of ultrasonic level transmitter (LT)

This lab test is done considering ground level as level of liquid and moving the LT on the 2m

scale and measures the distance, level of liquid and current output. This study is about the

ultrasonic Level Transmitter and uses it in the 2 meter long tank for level measurement, distance

and output current according to the level of tank.

Power Supply →110 volts

Maximum measuring distance of device → 2.0 meters

Maximum measuring range of device →1.8 meters

Blocking distance →0.2 meters*

Damping time → 60 seconds

Minimum measuring distance →0.2 meters

Lab results of SBB-49N-1 level transmitter

Distance (m) Level(m) Current(mA)(output)

1.196 0.605 8.06

1.101 0.698 8.99

1.001 0.798 9.97

0.901 0.898 10.99

0.803 0.996 11.96

0.798 1.001 12.01

0.607 1.192 13.92

0.402 1.397 15.97

0.300 1.499 16.99

0.297 1.502 17.02

0.258 1.541 17.41

0.203 1.696 17.96

0.200 1.601 18.01

0.191** - FAIL

0.150** - FAIL

0.102** - FAIL

*after this distance i.e. 200mm no result is found out as shown in table.

**these distance are measured mannually.

When this level transmitter is touched to ground LCD displays no Echo and FAIL.

All these results are taken in the lab.

INDUSTRIAL AUTOMATION

PLC (Programmable Logic Controller)

Digital electronic device that uses a programmable memory to store instructions and to

implement specific functions such as logic ,sequencing, timing etc to control machine and

processes.

Salient features

• Cost effective for controlling complex systems.

• Flexible and can be reapplied to control other systems quickly and easily.

• Computational abilities allow more sophisticated control.

• Trouble shooting aids make programming easier and reduce downtime.

• Reliable components make these likely to operate for years before failure.

Step 1- CHECK INPUT STATUS-First the PLC takes a look at each input to determine if it is on

or off. In other words, is the sensor connected to the first input on? How about the second input?

How about the third... It records this data into its memory to be used during the next step.

Step 2- EXECUTE PROGRAM-Next the PLC executes your program one instruction at a time.

Maybe your program said that if the first input was on then it should turn on the first output.

Since it already knows which inputs are on/off from the previous step it will be able to decide

whether the first output should be turned on based on the state of the first input. It will store the

execution results for use later during the next step.

Step 3- UPDATE OUTPUT STATUS-Finally the PLC updates the status of the outputs. It

updates the outputs based on which inputs were on during the first step and the results of

executing your program during the second step. Based on the example in step 2 it would now

turn on the first output because the first input was on and your program said to turn on the first

output when this condition is true.

DCS (Distributed Control System)

A distributed control system (DCS) refers to a control system usually of a manufacturing

system, process or any kind of dynamic system, in which the controller elements are not central

in location (like the brain) but are distributed throughout the system with each component sub-

system controlled by one or more controllers. The entire system of controllers is connected by

networks for communication and monitoring.

DCS is a very broad term used in a variety of industries, to monitor and control distributed

equipment.

Electrical power grids and electrical generation plants

Environmental control systems

Traffic signals

radio signals

Water management systems

Oil refining plants

Metallurgical Process Plants

Chemical plants

SCADA

It stands for Supervisory Control and Data Acquisition. It generally refers to an industrial control

system: a computer system monitoring and controlling a process.

Features of SCADA

1. Supervisory Control-Generally speaking, a SCADA system usually refers to a system that

coordinates, but does not control processes in real time.

2. Redundancy-When any device turns out to faulty the SCADA software will automatically

transfer the control to the redundant systems

3. Historical and Real Time Trends

4. Alarm-Alarms can set when a particular hi or low value is breached.

5. LAN Connectivity-It should have good LAN connectivity as it is necessary for connecting to

the ERP.

6. Dynamic Process Graphic-This has brought about revolution in automation as previously

people would not what was going in the system visually.

CONCLUSION

It was a great experience to be there in HZL for my practical training. During training period, I

certainly learnt a lot about every aspect of this field, right from the working environment to

the technical details of various equipments and process. Every industry functions with the help of

every branch individual whether computer science, mechanical, electronic etc. Relating to my

branch, I certainly learnt a lot about the instruments like ultrasonic level transmitter,

thermocouples, electromagnetic flow meters, pressure transmitters, etc and control systems like

DCS and PLC. To conclude, I would say that it actually showed the practical side of what I have

learnt in my curriculum. Also, it has helped to enhance my sense of professionalism and team

work.

REFERENCES

Training material provided by the Hindustan Zinc limited

en.wikipedia.org

google.com