I

Annexure A

PRODUCTIVITY AND QUALITY IMPROVEMENT IN

7-SERIES GRADES

BITS ZG629T: Dissertation

By

AMIT KUMAR VERMA

ID NO: 2011HZ79637

Dissertation work carried out at

M/s Hi-Tech Carbon (Birla Carbon) (Aditya Birla Group)

Renukoot, Distt Sonebhadra, UP (INDIA)

BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE

PILANI (RAJASTHAN)

November 2013

II

Annexure B

PRODUCTIVITY AND QUALITY IMPROVEMENT IN

7-SERIES GRADES

BITS ZG629T: Dissertation

By

AMIT KUMAR VERMA

ID NO: 2011HZ79637

Dissertation work carried out at

M/s Hi-Tech Carbon (Birla Carbon)

(Aditya Birla Group)

Renukoot, Distt Sonebhadra, UP (INDIA)

Submitted in partial fulfillment of M.S.Manufacturing Management degree

programme

Under the Supervision of R.K.RAGHUVANSHI (AGM-Production & Utility)

M/s Hi-Tech Carbon (Birla Carbon)

(Aditya Birla Group)

Renukoot, Distt Sonebhadra, UP (INDIA)

BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE

PILANI (RAJASTHAN)

November, 2013

III

IV

V

ABSTRACT

This project is related to innovation & break through step which has been carried out by student of this

dissertation who is the Employee of M/s Hitech carbon (Birla Carbon) Renukoot, (located in the

District of Sonebhadra,UP) under the Guidance of Mr R.K.RAGHUVANSHI who is supervisor of this

project. Objective of this study is to reduce the grit level of 7-series grade by application of systematic

approach of quality improvement. By performing systematic analysis of problem and implementing the

best possible solution we able to meet out our customer requirement and also retained our company

image as well.

In India, only Renukoot is producing this grade among the all three unit of Birla carbon in India, We

producing this grade since year 2000 for non-tyre segment only where the grit range was acceptable up

to 900 ppm.In January 2013, suddenly the demand came for Tyre-segment also for low grit 7-series

production i.e. 500 ppm max while our process capability was 700 to 800 ppm only. So this becomes

the challenge for Renukoot team because we had various problems in 7-series grades production, Like-

frequent coke formation, high cost, short run hrs, high grit and low photo.

By review of each and every process condition step by step, work out the probable and vital causes of

coke formation in Rx, made some new action plan and SOP. And by this way, we started closely

monitor the flame pattern, vertex formation and oil atomization pattern in Rx. Beside this, based on

pareto analysis, we found that our conventional “jacket position set up for production of 774”, which

was @ -250 mm distance from flush point of ring (ring which is located in combustion chamber)

creating big hindrance for proper oil atomization. Then we decide to change the jacket position and to

take the trial at new setup of Rx.

The first trial taken with jacket position @+50 mm and found that there is drastic change in product

quality. Grit level comes down in the range of 300 to 400 PPM from 800 PPM.After getting this result it

has been decided to take some more trial with same jacket position. Then we have taken 7-8 run and it is

the beauty of success that Renukoot plant able to achieve almost same range of grit level in “all runs”

without any coke flushing in Rxs.Finally we able to meet out our customer requirement and also

retained our company image as well.

VI

ACKNOWLEDGEMENT

First I offer my sincerest gratitude to my Supervisor Mr. R.K.RAGHUVANSHI

(AGM-Production & Utility), Hi-Tech Carbon, Renukoot, who has not only given me an opportunity to carry out this project but also extended the support throughout

my thesis work and allowing me the suitable time to work on this project. I attribute the level of my Masters degree to his encouragement and effort and

without him this thesis, possibly could not be completed. I also like to thanks Project Guide Prof. BK Rout (Faculty of BITS Pilani) and Dr S.Ganguly (AGM-

Quality control & ware house), Hi-Tech Carbon, Renukoot, for time to time guidance and support.

Finally, I would like to thanks all team of production dept and Quality control for

supporting me throughout the study and analysis related to quality improvement of 7-Series grade.

Date : 31.10.2013 AMIT KUMAR VERMA Place : Renukoot

VII

VIII

TABLE OF CONTENTS Ch no DESCRIPTION

Page no

1 Introduction 1-7

1.1- Introduction of the organization 2

1.2- Product Introduction (CARBON BLACK) 2

1.3- Classification of Carbon Black 3

1.4- Physico-chemical properties of carbon black 5

2 PROCESS DESCRIPTION 8-11

3 Objective, Scope and background the project 12-16

3.1- Objective 12

3.2- Scope of the work/project 12

3.4- Back ground of 7-series (N774/762) Grades 13

3.5- Key focused area 15

3.6- Methodology, Activity schedule and result target 15

4 Defining of problem and Data collection 17-21

4.1- Defining of problem 17

4.2- Quality performance before modification (Data collection) 19

5 Problem analysis and Root cause identification 22-25

5.1- Identification of causes 22

5.2- validation of causes 24

5.3- Root cause identification 25

6 Exploring of alternate solution 26-28

6.1- Analysis of Reactor flame and condition 26

6.2- Action plan made for execution of trial run 26

6.3- Execution of trial run 27

6.4-Result after implementation of solution 28

7 Regular implementation 29-32

7.1- Data collection after modification 29

7.2- Graphical presentation of Before-After performance 30

8 Productivity improvement and savings 33-35

8.1- Productivity improvement 33

8.2- Productivity gain 33

8.3- Saving in Auxiliary fuel oil 34

8.4- Other Tangible/Intangible benefits 34

IX

9 Standard operating procedure (after implementation of solution) 35

10 Conclusion and Summary of the project 36-38

10.1- Conclusion 36

10.2- Summary 37

10.3- Scope for future work 37

11 References 39

Check list 40

LIST OF FIGURE Fig no DESCRIPTION

Page no

1 Plant overview 2

2 Carbon Black 4

3 Structure of Carbon Black 4

4 Mechanism of Carbon Black formation 7

5 Process flow sheet 8

6 Background: Low grit N774 13

7 Defining of problem 17

8 Average grit (Before modification) 20

9 Average CpK (Before modification) 20

10 Why-Why analysis 22

11 Causes analysis by pareto diagram 25

12 Reactor picture 29

13 Graphical presentation of Before-After performance 30

14 Performance Comparison for grit level 31

15 Reactor peabody setting: Before-After (Cross sectional view) 31

16 Reactor peabody setting: Before-After 32

X

LIST OF TABLES Table no DESCRIPTION Page no

1 Background: Activities carried out 15

2 Action plan: Activity Schedule 16

3 Oil Quality 18

4 Quality Parameter of Product before modification 19

5 Data collection-Before 21

6 Root cause identification 25

7 Result after implementation of solution 28

8 Data collection after modification 29

9 Change in operating parameters (Before-After) 32

1

1 Introduction

Globalization and liberalization of Indian economy have led to Indian industries

to a highly competitive environment in the global market. The expectations of customers are quite high and choices are wide. Indian industries especially

manufacturing industries are facing challenges in competing with the multinationals due to dumping of material and opening of facilities in India. As

many foreign companies are setting up their base in India, suppliers to these multinationals have to meet their high procurement standard on quality without

any compromise and hence in this way the Indian manufacturing industries are always in pressure to improve the product quality, reduce cost and to make

customer delight. To survive in this highly competitive & customer oriented market, manufacturers should consider the following activities-

� Offer their products with distinct features and services

� Tracking & satisfy the changing taste of the customers

� Reach the market in time

� Be economical

The above activities lead to transform the Industry by

� Cost reduction

� Quality Enhancement

� Elimination of NVA (non value added activity)

� Productivity enhancement

� Delivery enhancement

2

1.1- Introduction of the organization

M/s Hitech Carbon, Renukoot (An Aditya Birla Group company)firmly known as “BIRLA CARBON”

as its Brand name, located in Sonebhadra Distt of Uttar Pradesh (INDIA), commenced operation in

1988, is a pioneer in the Carbon black industry. Present capacity of plant is 61,200 MT/Anuum.Capacity

of plant strategically increased by phase wise expansion from initial capacity of 20,000 MT/Annum at

inception. Birla Carbon is the world’s largest producer of carbon black with total 17 plants across the

world. The Unit is certified by BSI Management Systems India for the quality systems-TS16949:2009,

ISO14001:2004, OHSAS18001:2007, ISO27001:2005 & SA 8000:2008.The quality control laboratory

of the company is also accredited for ISO17025:2005 certification by National Accreditation Board of

Laboratories (NABL), Govt. of India for its carbon black testing facilities.

Fig no-1 PLANT OVERVIEW

1.2- Product Introduction (CARBON BLACK)

Carbon black is used as filler in rubber compound for making the tyre. Besides

giving the various physico-chemical properties Carbon black provide the

reinforcing ability to rubber compound and hence life of tyre increased

significantly. Apart from wide consumption in Automotive Industry, Carbon black

also used in other industries like- Paint, pigment, specialty and fine chemical

industries. At Renukoot, beside various ASTM grades, Carbon black is also

produced as customized grade based on specific customer requirement. Carbon

3

black being produced by thermal cracking of highly aromatic feed-stock (known as

conversion oil and it is the key raw material for production of carbon black) at high

temp and pressure in specially designed Reactors (Refractory lined, long tubular

reactor).

1.3- Classification of Carbon Black

Major classification of Carbon Black as Hard Black and Soft Black (also known as

Trade and Carcass respectively). For producing both kinds of blacks, two different

kinds of reactors are used. In Soft Black Reactors the heat required is supplied by

partial burning of CBFS while in case of Hard Black heat is supplied by complete

combustion of auxiliary fuel oil and partial burning of CBFS. Hard Black grade

particles are finer and gives higher abrasion resistance where as soft black grades

are coarser and exhibits better flexibility.

Common Hard Black grades:-

N110/115, N220, N234, N231, N326, N330, N347/N339, N375

All these grades of Carbon Black are used in the treads of tyres as these are highly

abrasion resistant.

Common Soft Black grades: -

N550, N650, N660, N774/N762 (7-SERIES)

All these grads are general purpose or fast extruding Carbon Blacks and find their use in the side walls of tyres and in the manufacture of tubes also.

First digit of the number denotes particle size. For example, N774 grade Carbon

Black particle diameter around 70 NM i.e. 70x10-9

M/s Hitech Carbon, Renukoot is producing more than 18 ASTM grades. Name of the some key grades

are N115/N220/N234/N330/N550/N660/N774 etc

4

Fig no-2 Carbon Black

Fig no-3 Structure of Carbon Black

5

1.4- Physico-chemical properties of carbon black

hysical and Chemical Properties

Primary Particle Size Arithmetic mean diameter calculated

by electron microscope.

Nitrogen Absorption Surface Area

Specific area characteristics calculated by using low-temperature

nitrogen absorption method. Generally, the larger the value, the

smaller the particle size.

Tinting Strength

Carbon black is milled together with zinc oxide to make a paste, the color

of which is compared with a standard specimen.

Using and absorpometer, the

amount of oil (DBP) absorbed per 100g is measured when DBP is

added to carbon black. Oil Absorption

The higher the structure, the higher the value.

Volatile Content

Percent by weight which is reduced

when carbon black is heated to 950°C for 7 minutes. The more the

surface functional groups, the larger

the value.

pH Value Value measured with glass electrode

pH meter when carbon black is mixed with distilled water.

Ash Content Remaining percentage by weight

when carbon black is burned at 750°C.

Surface Area

Very important in carbon black because it defines how much surface is available

for interactions with other materials present in a rubber compound. Small particle-

size black will have higher surface area, but the texture or nature of the surface

area can also influence the surface area.

BET method (ASTM D3037) being used to determine surface area of particles.

Adsorption of a gas, usually nitrogen, on the surface. Surface area can be

6

measured from electron micrographs also. Specialty furnace blacks require a

devolatilization step to remove residual oils present on the surface of the blacks.

Volume of void space between aggregates per unit weight of carbon black

increases with the number of particles per aggregate. Average particle size can be

estimated from statistical equations that relate tint strength and structure to

particle size as measured from electron micrographs.

Chemical Properties

Chemical nature of a carbon black is variable. Evidence for the presence on the

surface of at least four oxygen containing groups, carboxyl, phenol, quinone, and

lactone. Chemical surface groups affect the rate of cure with many vulcanization

systems. Physical adsorption activity of the filler surface is of much greater overall

importance for the mechanical properties of the general-purpose rubbers than the

chemical nature. Oxygen content influences the cure rate. Increased oxygen gives

longer scorch period, a slower rate of cure, and a lower modulus at optimum cure.

Amount of oxidation during the pellet drying operation can affect the cure rate and

modulus of rubber compounds. Carbon blacks are generally electrically conductive

because of the highly conjugated bonding scheme in crystalline regions.

7

Fig no-4 Mechanism of Carbon Black formation

Mechanism of Carbon Black formation in Reactor

Thermal Cracking of CBFS

(In the stream of high temp & high Velocity hot gases)

Carbon-Hydrogen gets decomposed

Carbon atom gets released (Also called tiny particle)

(size 1-2nm) (A0)

Primary Particle formed (Also called CB particle) (size 10-100nm)(A0-nm)

Primary Particle Fused together (with the help of K+ ion and hence

Aggregation started)

Carbon Black Aggregates formed

(Also called CB Structure)

Structure became stable after application of quench

Agglomeration started (Size 500-1000nm) (micron-mm)

Carbon black in pallet form (Size 0.5mm-1.5 mm)

8

2 PROCESS DISCRIPTION

In carbon black manufacturing process following are the key sections:

• Feedstock storage and pumping

• Reactor Section

• Bag Filter Section

• Pelletisation and drying Section

• Purge gas filter Section

• Conveying and Storage Section

• Packing and dispatch Section

Fig no-5 PROCESS FLOW SHEET

REACTOR MBF MICRO PCB

CYCLONE TANK

CYCLONE R / V

SURGE TANK

WET MIXER R / V

WET MIXER

SCREW FEEDER

DRYER

BUCKET ELEVATOR

CONVEYER SILO PGF

PGB

PACKING

9

A brief description of each section is given to understand the process-

Feedstock storage and pumping:

Carbon Black feedstock and auxiliary fuel received from the refineries are

unloaded in the storage tanks separately. Since the feedstock is quite viscous in

nature, special type of pumps and steam heating of the fluid is required for ease of

handling and pumping. Temperature of storage tanks maintained at about 60 - 80

°C temp. In the tank through external steam heating through steam coil.

Feedstock and auxiliary fuel supplied to the plant at high pressure of 25 - 30 kg/

cm² through pumps suitable for handling high viscosity fluids. The feedstock is

filtered through a fine mesh strainer/ filters to remove extraneous materials before

injecting to Reactors. Feedstock header pressure is maintained by automatic

controls by means of suitable control valves and controlling stations.

Reactor Section:

Since various types of Carbon Black can be produced by FURNACE BLACK

PROCESS under varying reaction conditions, two different designs of reactors are

employed for manufacturing of all grades of CB which are required by rubber,

plastic and pigment Industries. Preheated feedstock at about 170 - 240°C is finally

atomized and sprayed inside the reactor through specially designed nozzles made

of special material and water cooled guns. The reaction chamber which is lined

with high temperature chrome - alumina refractory is at a temp. Of approx. 1500 -

1900°C.

Partial burning of feedstock in case of SB Reactors, in presence of Air inside the

reactor raise the temperature about 1500°C and provide the endothermic heat for

thermal cracking reaction. The reaction products moving at very high velocities

are quenched with water sprays at predetermined locations inside the reactor to

about 700- 950°C. Sufficient length of refractory lined tunnel downstream of the

reactors is provided for complete vaporization of quench water. Energy from this

hot stream is recovered by heat transfer from product gasses laden with Carbon

Black particles to Cold air in a specially designed Air Preheater. The hot air at 650

- 800°C is used in the reactor thereby making substantial savings in the fuel

10

requirements in the reactor operation (Reactor is hereafter denoted as

Rx).Feedstock oil passed through the heat exchanger known as oil pre heater for

raising its temperature in the range of 170- 240 °C for better atomization of

feedstock and hence increasing the process efficiency and reduction in grit level

also. Product gases laden with Carbon Black particles ( now here after referred as

smoke) are cooled down to 280 - 290°C in a stainless steel quench tower and they

enter the MBF (Main bag filter) section for separation of Carbon Black from smoke

( a mixture of CO, CO2, CH4,C2H2,N2,H2, Air and water vapours).

Main Bag Filter Section:

Bag filter house is a large rectangular house having 7 compartments and a

hopper. Each compartment has 492 bags made of graphite + silicon treated fiber

glass bags. The bags have only bottom opening and are fixed securely to the

bottom thimbles and the top closed ends are secured to the hangers.

Smoke coming from reactor section at 270 - 290°C enters through the bottom of

bags and CB particles are deposited inside the bags. Clean gas filters off and goes

to "off gas header”. Cleaning of filter bag is done by reverse flow technique in

which each compartment is subjected to reverse flow of clean off gas through the

bags causing the deposited CB particles inside the filter bags to drop down into the

hopper. The reverse flow of off gas is achieved by sucking off gas from off gas

header and charging into each compartment by a repressure blower installed on

the ground. To keep the filter bags clean in all the compartment and continuous

separation and collection of Carbon Black, the reverse flow cleaning of each

compartment is done at regular intervals. The opening / closing of valves in each

compartment are regulated by a timer and through automatic control systems for

efficient utilization of bag filters.

CB material collected in the hopper section of bag filter is recovered through a

pneumatic blower and cyclone system to a surge tank (fluppy carbon holding tank)

for pelletizing and drying section. Before conveying, the material passes through

a Micropulverizer which crushes some hard carbonaceous particles and lumps. Off

gases collected in the off gas header are sent to pelleting and drying section and

11

energy conservation section for their 100 % utilization and thus eliminate the risk

of Atmospheric pollution.

Pelletizing and Drying section:

Carbon Black material collected in a large surge tank is sent to a pelletiser at a

constant rate through rotary valve to a pelletiser where it is mixed with water and

molasses solution to form wet pellets. Specially designed pelletiser is equipped

with a rotating shaft fixed with sharp edge pins in a double helix configuration. The

close gap between the pins and the inner smooth surface of pelletiser

accompanied by the conveying and rotating action of pins converts the mixture of

floppy CB powder and water into wet and strong spherical pellets. These wet

pellets are fed into a long rotary dryer through a dryer feeder. Pellets are dried

inside the hot rotating dryer by slow tumbling and falling action without damaging

the pellets. Dryer shell is enclosed in a refractory lined box all along its length and

the heat is supplied by burning of off gases received from the MBF section in a

specially designed refractory lined combustor furnace. Dry pellets with moisture

less than 0.5 % exit at the other end of the dryer for storage in the silos.

Purge gas filter section:

Water evaporated due to drying of wet pellets in the dryer along with some fines

material is removed by a purge gas blower at the feed end of the dryer. These

dust & moisture loaded hot gases are sent through a cylindrical bag filter house

called purge gas filter to remove and collect the CB particles and let out into the

atmosphere very clean, purge gases. Carbon Black collected in the conical hopper

is fed to the surge tank through a rotary valve and no carbon black loss is there in

the drying operation.

Conveying and storage section:

Dried pellets coming out at the exit end of the dryer are fed into a bucket elevator,

made of SS buckets to carry the material to the top of the silos. There are

numbers of silo to store the various grades of products.

Packing & Dispatch section: Material stored in the silos is packed through an

automatic packing machine. Packed bags are stacked on steel pellets for storage

and subsequent dispatch materials in truck to the consumers.

12

3 Objective, Scope and background the project

3.1- Objective

The objective of this project is to meet out the customer requirement in terms of

low grit, Productivity enhancement and reduction in cost of production by

elimination of NVA (non-value added activities), with the help of following measure

� Detail analysis of problem

� Probable and root cause identification

� Finding out of solutions

� To make the customized action plan to eliminate coke flushing activity

� Tracking of desired quality parameters of feed stock

� To make the customized SOP based on performance

3.2- Scope of the work/project

One of our key & valuable customer (name is not disclosed) beside other

customers, we have very stringent quality spec mainly sieve residue- less than

500 ppm (0.0500 in #325 mesh size with 100 gm sample).Since a long time we

are facing frequent coke formation problem in Rx during the N774/762 production

(Coke is undesired carboneous material formed inside the Rx which is the result of

un-decomposed oil droplet due to poor atomization and hence grit level increases

as impurity in finished product) and we need to do the coke flushing in both Rxs

(Unit has two nos of Soft black Rxs) at least once in each 24 hrs run result in high

off spec, quality variation and low CpK mainly in grit and Iodine/DBP beside other

tangible-intangible losses like-productivity loss and unwanted fuel oil consumption

etc due to frequent Rx inert(term “Rx Inert ” is referred as Rx is not under

production and only auxiliary fuel is being used in place of conv oil).For grade

N774 we are able to produce only about 20 % of total production volume in each

run for our said specific customer which meeting the sieve residue- less than 500

ppm and hence it is the big challenge for Hitech Carbon Renukoot to maximize the

production of low girt N774.Concerend student has taken this challenge as scope

13

and opportunity for taking this problem as a project for Quality & productivity

improvement.

3.4- Background of 7-series (N774/762) Grades

In 7 series grade N774 is one of most valuable product because only Hi-Tech

carbon, Renukoot is producing this grade among the all three unit of Birla carbon

in India. Though competitors In India are producing this grade but they are

producing with jumbo Rx only but Renukoot unit do not have jumbo Rx.N774 is

one of the typical grade in carcass black due to low iodine no, low photolemtric

value and high grit formation problem (Iodine no. is one of the key quality

parameters of carbon black denoting surface area while photolemtric value

indicating presence of un-decomposed oil in carbon black) and grit level (sieve

residue) is impurity which are present in traces amount in the finished product and

it is undesirable as it affecting end product by various ways. Minimization of grit

level in finished product is one of the key indicators for sound process operation

and performance of the Rx also.

BACKGROUND : LOW GRIT N774

GRIT @ 325 MESH

P

P

M

CHALLENGES

•NEW TYRE APPROVAL CAME IN FEB

2013 (<500 PPM GRT)

•RKT IS THE ONLY ERSTWHILE BC PLANT PRODUCING N774 IN INDIA

•PROCESS CAPABILITY WAS FOR NON

TYRE (>500 PPM GRT)

•ONLY 15-20% OUT PUT < 500 PPM :

MEETING NEW APPROVAL

•FREQUENT COKE FORMATION

•FREQUENT INERT : HIGH COST

•SMALLER RUN 12-16 HRS : MAX 40 MT

IN EVERY RUN

•BULK SUPPLY OF LOWER GRIT

MATERIAL TO NEW CUSTOMER?

Fig no-6 Background: Low grit N774

14

At Renukoot plant N774 being produce since year 1996 for non-tyre segment only

where the grit range (average total grit level in 325 mesh size) was acceptable up

to 1000 ppm .In January 2013, suddenly the demand came for Tyre-segment also

for low grit 774 i.e. 500 ppm max while process capability of HTC-R was 700 to

800 ppm only. So this becomes the challenge for Renukoot team because of

various problems in 774 production like- frequent coke formation, high cost, short

run hrs, high grit and low photo. Coke is undesired carboneous material formed

inside the Rx which is the result of un-decomposed oil droplet due to poor

atomization and hence grit level increases as impurity in finished product) and we

need to do the coke flushing in both Rxs (Unit has two nos of Soft black Rxs) at

least once in each 24 hrs run result in high off spec, quality variation and low CpK

mainly in grit and Iodine/DBP beside other tangible-intangible losses like-

productivity loss and unwanted fuel oil consumption etc due to frequent Rx

inert(term “Rx Inert ” is referred as Rx is not under production and only auxiliary

fuel is being used in place of conv oil).For grade N774 we are able to produce only

about 20 % of total production volume in each run for our new customer of tyre

segment which meeting the sieve residue- less than 500 ppm.

3.4.1-Various activities carried out to reduce grit level

Before taking this problem as project by the student of this Dissertation, various

effort and activities has been carried out by Renukoot team which is listed in

bellow mentioned table. Though the reduction in grit level observed but it was not

consistently in the range

15

Table no-1 Background: Activities carried out

Background-Activities carried out

PARAMETERS ACTION RESULT

FEED STOCK Changed the Oil Blend of CBFS: FO from

20:80 to 10:90

Marginal

improvement

BLEND

PREPARATION

Increased Blend Circulation time from 2

days to 4 days

Marginal

improvement

CLEANED OIL Used Centrifuge Showed

improvement, no

consistency

INCREASED

ATOMIZATION

PRESSURE

Increased Atomizing steam Pressure from

20 – 22kg/cm2g

Marginal

improvement

AIR TEMP Reduced Air Temperature up to 350 deg C Marginal

improvement

NEW NOZZLE Used TCB Nozzle No Change

STEAM FLOW Increased Steam Flow through by pass Line Marginal

improvement

Chronic problem taken as project

Student of this course has taken initiative to take this project and to fix the target

for at least 60% volume to produce N774 grade with grit level less than 500 ppm

in 325 mesh.

3.5- Key focused area

� To bring down the sieve residue below 500 ppm

� To maximize low grit production volume up to 70% in every run.

� To meet the internal & external customer requirements in time.

3.6- Methodology, Activity schedule and result target

A- Techniques & Methodologies:

� Data collection and compilation.

� Feasibility study

16

� Studying the present system being followed

� Exploring the alternative ways of Rx setup & operating condition

� Project Proposal preparation and approval for implementation

� Action plan/Process parameters/Feed stock Quality

� Work force /Investment (If any)

B-Action plan: Activity Schedule Table no-2

C- Result Target:

� 5% increase of productivity in N774 by reducing Rx inert hrs for coke flush.

� Up to 75% reduction of fuel consumption in N774 due to coke flushing

� Production of more than 70 % low grit material in each run to cater specific

customer requirement.

� 50% reduction of non-value added activities (Reprocessing of non-

conformance product).

� Target to improve product CpK of key quality parameters

(Iodine/DBP/Grit/Photo) by two fold.

1-15 16-31 1-15 16-28 1-15 16-31 1-10 10-20

1 Data Collection

2 Feasibility Study

3 Explore the alternative

Solution

4 Develop the new

process

5 Evaluation &

Implementation

Sl. No Activity Aug-13 Sept-13 Oct-13 Nov-13

17

4 Defining of problem and Data collection

4.1- DEFINING OF PROBLEM

Fig no-7 DEFINING OF PROBLEM

4.1.1- Data Collection (Before solving the problem)

In the way of data Collection first need to take the parameter at different stage of

process like Raw material Quality (conversion oil), Reactor Condition (Jacket

setup, flame condition), and Operating Parameter etc.

Current Scenario

Oil Temperature in Tank – 55-60 deg C

START

Change Peabody gun,

nozzle & fire the reactor

On smoke the reactor at 600 deg

smoke to APH

Is test

result

OK?

Take carbon sample from

dryer end & send for testing

Is test

result

OK?

Divert material to on

spec silo

END

YES

NO

YES

NO

Is grit in

permissible

limit?

NO

YES

Change jacket position as per

requirement & check alignment

Maintain input parameters

(oil, air, additive etc.)

Take carbon sample from

reactors & send it for testing

PROBLEM

AREA

18

4.1.2- Oil Quality

Table No. 3 (Oil Quality)

Parameter Range

Blend oil ratio 80% FO (furnace oil) & 20% CBFS

(Carbon black feed stock-Imported)

Sp Gravity @

(15.56 deg C) 1.0182-1.0184

Viscosity 93-98

BMCI 90-95

API 5.0 to 6.0

Moisture 0.5-0.7

4.1.3- Reactor Setup

Jacket Position- -225 mm (minus Distance from Ring)

Atomization Media- Steam or compressed Air (Pressure 12.0 kg/cm2,

Temperature 50-60 deg C)

Quench Water Gun Position- Co-current/counter current of Stream Flow

Operating Parameter

Oil Temperature 160-175 deg C

Reactor Inlet Air Temp 480-510 deg C

Flow of Atomization Media (steam/Air) 150 kg/hr

Quantity of Additive (KNO3) used as per requirement

(Additive is a potassium compound solution with water of Sp. gravity 1.10, which

used in reactor to maintain the desired structure of carbon black)

19

4.2- Quality performance before modification (Data collection)

To analyze quality parameter, data has been collected for 3 month of various run-

Table No. 4 (Quality Parameter of Product before modification)

Avg. Oil

ratio

Avg. Grit Level at Diff.

Mesh Size

CpK

Lot No.

Rx

A Rx B #325 #100 #35 Iodine DBP #325 #100 #35 photo

R041A2C 7.8 8.2 0.049 0.0109 0.0002 -0.13 0.55 1.65 1.81 0.67 0.56

R043A2C 8.5 8.2 0.068 0.0129 0.0006 0.01 0.65 0.7 0.81 0.44 1.31

R046A2C 7.6 8 0.096 0.0219 0.0013 -0.04 0.78 0.04 0.06

-

0.06 2.59

R051A2C 8.4 8.1 0.103 0.0166 0.0005 0.2 0.92 0.03 -0.52 0.42 4.77

R054A2D 8.3 8.2 0.0801 0.0191 0.001 0.14 0.93 0.29 0.22 0.00 1.14

R062A2D 7.3 8.05 0.0855 0.0166 0.0011 0.35 0.64 0.17 0.31

-

0.03 0.69

R064A2D 8 7.7 0.111 0.0236 0.0025 0.33 1.17 -0.14 0.05

-

0.25 2.79

R066A2D 7.6 7.5 0.0844 0.019 0.0023 0.07 0.57 0.22 0.33

-

0.29 2.34

R068A2E 7.4 6.5 0.0671 0.0112 0.0007 0.42 1.04 0.65 2.3 0.17 1.71

R072A2E 7.8 7.7 0.089 0.015 0.002 0.09 0.44 0.16 0.39

-

0.11 1.22

R075A2E 7.0 7.8 0.085 0.015 0.001 0.03 0.66 0.27 0.54 0.06 -0.16

R077A2E 6.5 7.0 0.063 0.017 0.001 0.35 0.7 1.03 0.58 0.17 0.35

R079A2E 6.9 7.2 0.087 0.026 0.002 0.2 0.63 0.15 -0.03

-

0.21 2.14

R081A2E 6.8 7.3 0.071 0.017 0.002 0.14 0.47 0.46 0.37

-

0.33 0.42

20

Average Grit Level

Avg grit level-Dryer stage (#325 mesh)

0.049

0.068

0.096

0.103

0.08010.0855

0.111

0.0844

0.0671

0.0890.085

0.063

0.087

0.071

0

0.02

0.04

0.06

0.08

0.1

0.12

R041A2C R043A2C R046A2C R051A2C R054A2C R062A2D R064A2D R066A2D R068A2D R072A2E R075A2E R077A2E R079A2E R081A2E

Lot No.

grit le

vel

Fig no-8 Average Grit (Before modification)

CpK of All Parameter

CpK-Iodine/DBP/grit- Dryer

-0.13

0.01-0.04

0.20.14

0.35 0.33

0.07

0.42

0.090.03

0.35

0.20.14

0.550.65

0.78

0.92 0.93

0.64

1.17

0.57

1.04

0.44

0.66 0.70.63

0.47

1.65

0.7

0.04 0.03

0.29

0.17

-0.14

0.22

0.65

0.16

0.27

1.03

0.15

0.46

1.81

0.81

0.06

0.220.31

0.05

0.33

2.3

0.39

0.54 0.58

-0.03

0.37

-0.5

0

0.5

1

1.5

2

2.5R041A2C R043A2C R046A2C R051A2C R054A2C R062A2D R064A2D R066A2D R068A2D R072A2E R075A2E R077A2E R079A2E R081A2E

CpK

Iodine DBP #325 #100

Fig no-9 Average CpK (Before modification)

21

Quality performance-grit level

Table no-5

Data Collection before Problem Solving

Lot NoGrit @325 mesh

Avg Grit(ppm) Cpk

R075A2E 850 0.27

R077A2E 630 1.03

R079A2E 870 0.15

R081A2E 710 0.46

Overall Average 765 0.48

Lot NoGrit @325 mesh

Avg Grit(ppm) Cpk

R075A2E 850 0.27

R077A2E 630 1.03

R079A2E 870 0.15

R081A2E 710 0.46

Overall Average 765 0.48

22

5 Problem analysis and Root cause identification

Study has been carried out at different stages of process & finish Product quality

parameter which found from 14 runs of N774 production. During why-why analysis

numbers of probable causes of Coke formation in reactor were emerged out.

5.1- Identification of causes

( Why Why Analysis )

WHY?

Oil accumulation on

surface

Coke formation in Reactor

Poor flame pattern

WHY?

Jacket

position is

-250mm

Improper

Jacket

Alignment

Secondary air flow

is not proper

Peabody nozzle

chokage

WHY?

WHY?

Low oil

temperature

Flame striking

the 500mm ring

Wrong indication of

secondary air flow or

leakage from damper

Insufficient flow of

atomization media

WHY?

High grit level in N774

Improper

atomization of oil

WHY?

WHY?

Foreign

contamination in

oil

Choked or damage

oil strainer

High air

temp

High

additive flow

Fig no-10 Why-Why analysis

23

So potential causes were emerged out by why-why analysis are-

1. Low oil temperature

2. Low pressure & insufficient flow of atomization media

3. Choked or damage oil strainer

4. Jacket position is -250mm

5. Improper Jacket Alignment

6. High air temp

7. Wrong indication of secondary air flow or leakage from damper

Role of some of the causes has been discussed here-

1- Low oil temperature

Low oil temperature may be a cause of Coke formation in reactor, because due to

low temp oil is not getting atomized properly due to higher viscosity of oil.

In current Scenario Peabody jacket position was -225 mm from ring. It may be a

cause of Coke formation, because in this case spray of atomized oil gets hindrance

with 500 mm dia ring which is located inside the Rx.

2- Low pressure & insufficient flow of atomization media

If atomizing media pressure & flow is not sufficient oil will not get atomize which is required for

proper cracking of oil and result in formation of coke.

3- Choked or damage strainer

Choked strainer will cause the insufficient oil flow while damage strainer will cause the passing of

foreign contamination along with oil and result in chokage of Peabody gun tip (nozzle) and hence

poor spray of oil which is responsible for coke formation.

4-Jacket position is -250mm

Since beginning (when the 7-series production started at Renukoot plant) we are running jacket

position with this setup i.e. in the range of -200 to -250 mm. So we have to further analyze that

whether this position of jacket is responsible for coke formation or not and for its analysis we have

to closely monitor the flame pattern and reactor condition after the completion of 7-series

production for each and every run.

5- Improper Jacket Alignment

Improper Jacket Alignment will cause of heating the spray on the wall of ring or/and shell hence

instead of cracking it stick on the surface and result in formation of coke. However this cause is

not the reason of coke formation as in current scenario jacket has been tightened with tie rod

which will always keep the jacket remain intact on the properly aligned position

24

6- High air temp

During production of N774, when very high grit level started coming in dryer sample When we

analyzed the grit nature (physical appearance of grit) we found that in most of the run grit was very fine,

powdery and ash type material. One of the major reasons of such type of grit formation is possible

only, when the oil droplet will get burn in maximum amount in place of desired partial combustion

which is important for thermal cracking of atomized oil. Inlet air temperature plays an

important role in carbon black production. Desired temperature for cracking is

provided by the preheated air which is coming in Rx through APH (Air Preheater).Different grade of carbon black will produce at different cracking temperature. In combustion chamber higher % burning of conversion oil (before the minimum

required time to get oil droplet atomized with atomizing media) is due to oil droplet get interact with

very high temp air flow than desired air temp for 7 series grade.

7-Wrong indication of secondary air flow or leakage from damper

In case there is insufficient flow of secondary air due to wrong indication or leakage from damper

flame will not established properly which is important for forming the proper vertex & whirling

effect for getting better flame profile.

5.2- Validation of causes

We reviewed each and every process steps start from raw material unloading in oil

storage tanks to atomization of oil in Rx based on potential causes emerged out

from why-why analysis except one causes that is jacket position -250 mm,

because if there is any contribution of existing jacket position we have to work out

that where we have set the new position of jacket. For this we have decided to

take some reference from old CFD (computational fluid dynamics) study. We

followed to adopt all possible activities to eliminate the effect of all potential

causes one by one for observing the improvement contribution. We analyzed the

result and observed that there was considerable improvement in grit level

reduction but we still not able to get desired quality range for low grit production.

Then we decided to take the advantage of 80-20 principle by doing the Pareto

Analysis to work out that out of all identified potential factor/causes from why-why

analysis, which factor is giving maximum % of impact.

25

5.3- Root cause identification (Table no-6 )

Finding of Root cause by pareto analysis

Causes Observation Cum

observation percentage

Cumulative percentage

Jacket position is -250mm 11 11 55 55

Low oil temperature 3 14 15 70

High air inlet temperature 3 17 15 85

Insufficient flow of atomization media 2 19 10 95

Wrong indication of secondary air flow 1 20 5 100

Damage oil strainer 0 20 0 100

Improper Jacket Alignment 0 20 0 100

Total 20

Cause analysis by Pareto Diagram

11

3 3

2

1

0 0

55

70

85

95100 100 100

0

2

4

6

8

10

12

Ja

ck

et

po

sit

ion

is

-25

0m

m

Lo

w o

il

tem

pe

ratu

re

Hig

h a

ir t

em

p

Ins

uff

icie

nt

flo

w

of

ato

miz

ati

on

me

dia

Wro

ng

in

dic

ati

on

of

se

co

nd

ary

air

flo

w

Da

ma

ge

oil

str

ain

er

Imp

rop

er

Ja

ck

et

Ali

gn

me

nt

Causes

Fre

qu

en

cy

-10

10

30

50

70

90

110

Cu

mu

lati

ve

%

Vital few Useful many

Fig no-11 cause analysis by pareto diagram

26

6 Exploring of alternate solution

6.1-Analysis of Rx flame and location

Based on the finding of vital cause i.e. Jacket position “-250 mm’ emerged out

from Pareto analysis which was contributing more than 55% , we have started

close monitoring of flame pattern and location of coke formation in every run for

finding the solution of above mentioned “vital cause”. We found that flame is

striking on the ring and coke is forming near the area of secondary air inlet point.

Beside this we have taken the reference of old CFD result as we planed in

“validation of causes” These observation is now validated the list out of probable

causes under the head- “poor flame pattern’ during the why-why analysis

exercise.

So we decided to keep the jacket position at +50 mm (i.e. placing jacket at just

outer edge of ring) and make a robust action plan to take one trial run.

6.2- Action plan made for execution of trial run

Besides taking the action on high contributing factor i.e. jacket position we have

decided to take in consideration of other contributors- Oil temperature and high air

temperature which are having each one 15% impact to get the maximum benefit

for successful production of low grit material.

Following action plan made for trial run-

1. Keep both Rx jacket Position “+50” mm

2. Maintain Air Temp – between 425- 450 in both Rx (Start reduce air temp

before grade change in such a way that during on-smoke temp should not

more than 450 deg

3. Blend sample to be check and try to maintain viscosity around 80-85 which

will help in better atomization.(this viscosity may achieve with 70/30 blend

ratio)

4. Based on the Rx grit, proactively disturb the jacket position in the range of

“+25” to “+75 mm“(avoid to cross this limit) for half an hour and again

27

revert to original position “+50”. Use this activity only when dryer grit going

above 0.04/0.05

5. If grit level touching to 0.07 skip step #4 activity and based on Rx girt result

(in 100 gm sample), do the coke flushing of the Rx which is having high grit

to avoid silo contamination

6. Initially, Start production with low rating i.e. 5000 air flow in both Rx.To

increase rating instead of increasing in one shot, increase 250 nm3 rating in

both Rxs at once and next increase in 2 hrs gap to maintain grit level.

7. Tank temp to be maintain between 75-80 (earlier it was running 60 deg

approx in N774) it will help in increase of TIC temp as N774 TIC normally

running quite low specially in RxA.

8. After on-smoke, If desired girt level not achieved set jacket position

+75mm instead +50 mm

9. Increase strainer cleaning frequency of blend tank when tank circulation

started.

10. Ensure there is no any air leakage form 2ndry air damper

6.3- Execution of trial run

The first trial taken with jacket position @+50 mm and found that there is drastic change

in product quality. Grit level comes down in the range of 300 to 400 PPM from 800

PPM.After getting this result it has been decided to take some more trial with same jacket

position. Then we have taken 7-8 run and it is the beauty of success that Renukoot plant

able to achieve almost same range of grit level in “all runs” without any coke flushing in

Rxs.Finally we able to meet out our customer requirement and also retained our company

image as well.

28

6.4 Result after implementation of solution

Table no-7

Lot No Grit @325 mesh

Avg Grit (ppm) Cpk

R111A2G 321 3.84

R122A2G 373

3.80

Overall Average 347 3.82

29

7 Regular implementation

Fig no-12 Reactor picture

7.1 Data collection after modification (Table no-8)

Data collection after regular implementation of solution

Avg Grit CpK

Avg Oil

ratio Lot no

RxA RxB

#325 #100 #35 Iodine DBP #325 #100 #35 photo

R086A2F 6.40 6.40 0.041 0.010 0.000 1.08 0.91 2.41 1.9 0.78 0.87

R095A2F 6.90 6.80 0.036 0.012 0.001 0.62 0.98 2.48 1.1 -0.04 2.02

R099A2F 7.04 7.00 0.039 0.012 0.000 0.71 0.91 4.4 2.12 0.78 3.13

R102A2F 7.30 7.20 0.0297 0.0086 0.0004 1.28 1.59 4.78 2.73 0.5 3.78

R104A2F/R105A2G 7.20 7.00 0.0323 0.0097 0.0002 1.305 1.305 4.91 3.845 1.78 3.845

R111A2G 7.00 7.15 0.0321 0.0091 0.0005 0.66 0.66 3.84 1.96 0.42 1.62

R117A2G 7.25 7.25 0.0443 0.0101 0 0.78 1.31 2.99 2.07 0 0.62

R122A2G 7.10 7.03 0.0373 0.0106 0.0004 0.75 0.8 3.8 2.82 0.67 0.63

R142A2I 7.19 7.16 0.0425 0.0095 0.0004 0.55 0.89 2.15 2.15 0.33 0.04

Solution implemented in all runs of 7-series grade

SOP: - Change Peabody jacket position to +50 in 7-series production

30

7.2 Graphical presentation of Before-After performance

CpK Trend - Iodine/DBP/GRIT-#325 MESH

0.03

0.350.2 0.14

1.305

0.660.78 0.750.66 0.7 0.63

0.47

1.305

0.66

1.31

0.8

0.27

1.03

0.15

0.46

4.91

3.84

2.99

3.8

0

1

2

3

4

5

6

R075A2E R077A2E R079A2E R081A2E R105A2G R111A2G R117A2G R122A2G

Lot no

CpK

Valu

e

CpK Iodine CpK DBP CpK #325

performance after

implimentation of solution

BEFORE

AFTER

Avg Grit #325 mesh (retained in grams out of 100 gm sample)

0.085

0.063

0.087

0.071

0.0323 0.0321

0.0443

0.0373

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

R075A2E R077A2E R079A2E R081A2E R105A2G R111A2G R117A2G R122A2G

Lot no

gri

t ra

nge

R075A2E R077A2E R079A2E R081A2E R105A2G R111A2G R117A2G R122A2G

performance after

implimentation of solution

(0.085 gm means 850 PPM)

BEFORE

AFTER

Fig no-13 Graphical presentation of Before-After performance

31

7.1- Follow-up and review

Fig-14 Performance Comparison for grit level

7.2- Changes after modification

ModificationModification

Fig no-15 Reactor peabody setting: Before-After (Cross sectional view)

performance Comparison for grit level

765

500347

0

200

400

600

800

1000

Before Target After

Average grit level @ 325 mesh in N774

32

2424

BEFORE

AFTER

Soft Black Reactor

Soft Black Reactor

Jacket position

-250 mm

Jacket position

-250 mm

Jacket position

+75 mm

Jacket position

+75 mm

Fig no-16 Reactor peabody setting: Before-After

Table no-9 change in operating parameters (Before-After)

Before-After details for change in operating parameters for low grit production

ACTIVITY BEFORE AFTER REMARK

1 Jacket position -200 to -250 mm from

ring +50 to

+75mm For hindrance free oil atomization

2 Tank oil temperature in charge tank 55-60 C 75-80 ºC

To reduce oil viscosity for easy atomization

3 Oil temperature after oil pre heater 160-175 C 185-210 C

To reduce oil viscosity for easy atomization

4 Air inlet temperature to Reactor 470-510 425-460

To control high % of early combustion of conv oil so that oil get time to atomized

33

8 Productivity improvement and savings 8.1- Productivity improvement by elimination of coke flushing activities-

Hitech carbon, Renukoot having two nos Soft black Rxs. Maximum/allowable run

hrs in each run of N774/N762 is 24 hrs.In each run we have to flush the Rx due to coke formation for at least 1.0 hr one by one for both Rx.Daily production rate (in

case of 24 hrs run) is 58 MT.Renukoot unit is producing 4 runs of 24 hrs in every month on an average basis.

Amount of production in 1 hr = 58/24

= 2.416 MT So, every month production enhancement = 2.416*4

= 9.66 MT Annual production enhancement (expected) = 9.66*12 = 115.968 MT

Annual production @ 58 MT/DAY = 58*4*12= 2784 MT

Hence % of expected productivity improvement every year by elimination of coke

flushing activity = (115.968*100)/2784 = 4.16%

% productivity improvement in 7-series grade = 4.16%

8.2- Productivity gain (Monetary benefit due to extra production):

Annual production enhancement (expected) = 9.66*12 = 115.968 MT

Productivity gain (Realization) with 1.0 MT of N774/762 = Rs 6950 (Approx)

So Annual productivity gain (Realization) with total 115.968 MT production enhancement = 115.968*6950

= Rs 8, 05,977 (Approx)

34

8.3- Saving in Auxiliary fuel oil due to elimination of coke flushing

activity:

Numbers of Reactors= 2 Each run coke flushing time= 60 min* 2 Rxs = 120 min

Auxiliary fuel oil flow during coke flushing = 4.5 liter/min So, total non productive fuel oil consumption = 4.5*120

= 540 liter Or, each run non productive fuel oil consumption = 0.540 KL

Approx numbers of run annually = 12*4 = 48 runs

So, expected saving in Auxiliary fuel oil due to elimination of coke flushing activity

= 48*0.540 = 25.92 KL

Average price of fuel oil = Rs 42,000/KL

So, expected money saving in Auxiliary fuel oil due to elimination of coke flushing

activity = 25.92*42000 = Rs 10, 88,640.00

So, Total annual saving (expected) = productivity gain + saving in auxiliary fuel = 8, 05,977+10, 88,640

= Rs 18, 94,617.00 (Approx)

8.4- OtherTangible/Intangible benefits by Innovation in N774 production

Customer satisfaction

1 100 % delivery of required volume (earlier we able to seggrigate only 15-20% low grit material)

2 100% meeting of Quality as per customer spec

3 On-time dispatch (zero delay due to quality and volume)

5 Uninterrupted gas supply to internal customer i.e. Utility Dept

Off-spec reduction

1 Significant reduction in off spec in high grit both at dryer stage and FG stage

3 Elimination of silo contamination and off spec due to inert-down for coke flushing

Saving of fuel oil

1 Saving of fuel oil in Boiler also which was incurred in earlier case due to frequent coke flushing

Run hrs increased

1 Able to increase run hrs (from 24 hrs to 27 hrs)

Better House keeping

1 Able to maintain better house keeping and 5S activity as there is no oil spillage during Peabody gun changeover and pocking rod requirement in every run of N774

35

9 Standard operating procedure (after implementation of solution)

Based on performance study and follow-up observation, action plan made for trial

run has been reviewed with some changes and following SOP has been made for flaw less execution of 7 series production in every run. SOP’s are as follows-

1. Keep both Rx jacket Position “+50” mm

2. Maintain Air Temp – between 425- 450 in both Rx (Start reduce air temp before grade change in such a way that during on-smoke temp should not

more than 425 for low grit material (for nomal grit 450c is ok). 3. Keep atomizing steam and 2ndy air damper in both Rxs full open

4. Blend sample to be check and maintain viscosity around 80-85 which will help

in better atomization.(this viscosity may achieve with 70/30 of oil blend ratio) 5. For low grit production if dryer grit level increases above 400/500 PPM

immediately check the Rx grit (in 100 gm minimum) & photo. 6. Based on the Rx grit, proactively disturb the jacket position in the range of

“+25” to “+75 “(avoid to cross this limit) for half an hour and again revert back at “+50”. Use this activity only when dryer grit going above 400/500

7. During low grit production if dryer grit level touching to 700 skip step #6 activity and based on Rx girt result (in 100 gm sample), do the coke flushing

of the Rx which is having high grit to avoid silo contamination which normally happen due to continuous 0.1 grit during Rx inert activities at high girt level.

8. Initially, Start production with low rating i.e. 5000 air flow in both Rx (This is much important if we are producing low grit material).To increase rating

instead of increasing in one shot, increase 250 nm3 rating in both Rxs at once and next increase in 2 hrs gap to maintain grit level.

9. Tank temp to be maintain between 75-80 it will help in increase of TIC temp

as N774 TIC normally running quite low specially in RxA (It observed that tank temp is increasing very slow even after opening of bypass valve, so start

increasing temp 2-3 days before to get desired temp during production) 10. L-2 Oil cooler keep stop if required to get desired tank temp.

11. Increase the photo & grit testing at Rx end throughout the N774 run. 12. After on-smoke, If desired girt level not achieved set Rx-A jacket position

+75mm instead +50 mm 13. Quench gun to be kept co current and avoid end location guns (towards

APH) to prevent APH fouling (at 425-450 deg air temp there is possibility of quick fouling of APH)

14. Change Rx strainer one by one during Rx inert and get maximum oil flow through off smoke valve.

15. Increase 20 kg steam pressure (21/22) from utility when production start. 16. Increase strainer cleaning frequency of blend tank when tank circulation

started.

17. After following all above mentioned SOP, if there is coke formation problem. Check the atomizing steam flow and 2ndry air flow indication.

36

10 Conclusion and Summary of the project

10.1- Conclusion

Uninterrupted atomization of conversion oil inside the Rx mainly in carcass Rx is

prime condition which is responsible for proper cracking of oil droplet for getting

desired quality and to avoid coke formation. Production of 7 series grade

(N774/762…) required utmost care for “hindrance-free” oil atomization as it is the

most typical grade in carcass black due to low iodine, low photo and high grit

formation problem.

Methodology/ Approach adopted to solve this chronic issue of coke formation by

concerned student was application of different problem solving tools and technique

like- why-why analysis, pareto diagram, adopting of best practices and break

through action.

Why “+50 to +75” is best jacket position for N774/N762

“+50 to +75” mm jacket position will provide hindrance-free best mixing rate

(instead +100/ +150 and so on…) because in this setting of jacket, main air just

at exit point of outer face of ring (also known as choke/orifice, provided for

increasing air velocity and turbulence for getting better air temp and better mixing

respectively) will have maximum whirling and it will decrease as jacket go away

from ring (towards ring discharge) while at flush position or at any minus position

of jacket setting (up to the edge of inlet face of ring) main air will create

hindrance for oil atomization however in this zone air oil mixing rate will be

maximum and hence oil ratio will also increase but due to hindrance in atomization

coke formation will occur rapidly.

37

10.2- Summary of the project

This project has resulted in major benefits in terms of Productivity, Quality and

Cost. Enhanced the Internal and External Customer delightness in terms of on-time delivery of right quality & quantity product and elimination/reduction of

rework & reprocessing of non-conformance material respectively. Beside this, out come of this project also greatly reduce the mental stress of shift team of both

production and Utility dept due to significantly reduction in frequent reactor inert-down and coke flushing activities.

Based on the experiments conducted, it is clearly evident that the Process

optimization, modification and deep study/analysis resulted in “ZERO” defects in product.

10.3- Scope for future work

Step wise future plan can be made for further benefit in 7-Series production 1) - Use of Tank no-1283 as charge tank for 7-series production after circulation line modification. Explanation (Why) - Tank no-1283 & 1284 circulation line connected

with drain line of tank. Accumulated/settled foreign material or slurry

will mixed in tank through tank circulation and hence all the time oil in Rx comes with this suspended material. Suggestion- For tank no- 1283 one suction point available at 500 mm

height from base but this point is normally not in use for circulation so

to avoid mixing of bottom oil we should use this point for circulation

(there is no issue for using this point, same is already checked) Benefit- Bottom oil/accumulated foreign material if any at the tank

bottom can be prevent to mix in tank via tank circulation during the

N774 production and hence probability of coke formation can be

eliminated.

2) - Trial to be taken with 60:40 blend (FO: Imp) in place of 70:30 for

yield gain

3)- Trial to be taken with atomizing air initially in one Rx (to be done after steam coil tracing in atomizing air line to increase temp of

38

atomizing air so that better atomization can be achieved which will

contribute in further quality enhancement and yield gain)

5) - It has been observed that oil temperature of existing charge tank

is increasing very slowly (probably due to scaling on steam coil, tube

cleaning plan can be made as futue plan). So to get the desired

temperature in the range of 75 deg C to 80 deg C, plan to open the

steam control valve 2-3 days before of actual production plan Note- a) For better performance we should use GA-9.5W or 14W

nozzle as wide angle will give maximum distribution/coverage on WHB

tube)

b) Tracking of Rx back pressure consistency will helpful in taking alert

for coke formation symptoms

39

11 References

1- J. B. Donnet, R.P. Bansal, and M. J. Wang. Carbon Black: Science and Technology. New

York: Marcel Dekker Inc, 2003.

2- J.M.Juran. Juran on Planning for Quality. The Free Press, 9th Impression edition, 1988

40

41