This company has two types of dryers âSteam bed ... Vacuum bed dryer is rarely used; generally steam bed drier .... The sludge is sent to drying beds where.
A Project Report on Summer Industrial Training (Six Weeks) June-July (2016) Subject code: UCH591
Submitted to: Dr. Neetu Singh Assistant Professor Department of Chemical Engineering Thapar University, Patiala-147004, Punjab, INDIA
Submitted by: Tarun Jain Roll number- 101401083 BE Chemical Engineering - 2 ND Year
1
DECLARATION
I hereby declare that this project work is an authentic record of my own work done under the supervision of my mentor Mr.Vibhor Jain at Indswift laboratories, Dera Bassi, Punjab.This project work is only meant for submission to the Chemical Engineering department, Thapar University as the requirement of 6 week industrial training. All the data used in calculations is correct to best of my knowledge and observed practically in the plant.
Tarun Jain 101401083
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ACKNOWLEDGEMENT
I would like to take this opportunity to express my gratitude and sincere thanks to my mentor Mr. Vibhor Jain who offered me the chance to explore each and every plant in the industry. He helped me in coordinating and getting information from various departmental heads. I would also like to thank my teachers, Dr. Jai Prakash Kushwaha and Dr. Avinash Chandra for helping me throughout the course of internship, guiding me and being a constant source of motivation. Last but not the least, a word of thanks to the management of Ind-swift laboratories Limited for selecting me in their summer internship program.
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ABSTRACT
This report contains detailed information about each and every single process, equipment, plant investigated by me during the internship. In this report all the types of equipment are mentioned and the ones being used in the industry are especially distinguished. All the operating parameters of a specific plant are specified. A brief s tudy on the flow path of shell and tube heat exchanger is also expressed and thermal design of shell and tube heat exchanger is also provided using LMTD method and NTU effectiveness method. Second phase of the internship contains landfill and solid waste treatment techniques used in the Punjab State.
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INDEX Chapter no.
1.
2.
3.
4.
Content
Page no.
Introduction to company
6
Equipment in the Solvent recovery plant
7
1.1 Reactor
7-8
1.2 Distillation column
8-11
1.3 Agitator
12
1.4 Collector/Receiver
13
1.5 Phase separator
13
1.6 Level Indicator
14
1.7 Rotameter
14
1.8 Pumps
15
1.9 Valves
16
Solvent Recovery Plant
17
2.1 Systems and Processes
17-18
2.2 Azeotrope distillation(Batch and Continuous)
18-21
3.1 Reboiler
22
3.2 Safety and precaution measurements
23-25
Pilot Plant
26
4.1 Reaction
27
4.2 Distillation
27
4.3 Crystallization
27
4.4 Centrifuge/Filtration
27
4.5 Drying
27
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4.6 Finishing of the product
28
Environmental plant
29
5.1 Multi-effect evaporator (MEE)
30-32
5.2 Effluent treatment plant (ETP)
32-33
5.3 Reverse Osmosis (R.O)
33-34
5.4 Incinerator
35-36
6
Quality control and Quality assurance department
37-38
7
Nimbua Greenfield Punjab ltd
39-40
7.1 Landfill/CHWTSDF
40-41
Shell and tube heat exchanger
42
5.
8
8.1 Thermal design of Shell and tube heat exchanger-a mini project
43-47
Conclusion
48
References
49
Appendices
50
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ABOUT THE COMPANY
Established in 1986 by
the Jains,
the
Mehtas
and
the
Munjals, Ind-Swift is
a
leading pharmaceutical manufacturing and marketing company in India, based in Chandigarh. Its strength lies in innovative pharmaceutical products. Ind -Swift has been ranked 35th in the Indian pharma industry and is the second largest among the drug manufacturers in India (north India). It has spread its network across 45 countries. It is an ISO 9001-2008, WHO GMP certified company. It is also listed on the Bombay Stock Exchange and National Stock Exchange. It has 5 plants in India which include multi purpose, multi-location facilities spread across northern India.
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CHAPTER 1 Equipment used in the plant:
Reactor Distillation columns Agitators Collectors/Receivers Phase separators Level Indicators Rotameters Pumps Valves
1.1 Reactors Batch Reactors Stainless steel tank reactor (SSTR) Glass Lined Reactor (GLR)
Reactors used in Solvent Recovery Plant (SRP) Stainless steel tank reactor (SSTR) Kettle type reactor (one in each SRP) Notes: 1. Stainless steel reactors are mostly used for basic solutions acid may corrode steel. 2. Glass lined reactors are used for acidic solvents and acidic mixtures. 3. Reactors are provided with a jacket outside for heating and cooling the reactor, we cannot burn the reactor from the bottom, that’s the reason we provide a jacket. 4. Reactors contain disc like openings on the top surface to connect various lines for charging the reactor. 5. Kettle type reactors are different types of reactors. There is a minute difference in kettle type and stainless steel type reactors. The difference is that kettle type reactors do not contain agitator. 6. Outside coating of reactor is done with Aluminum which helps in prevention from corrosion.
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Fluids used for heating and cooling the reactors 1. Fluids for heating the reactors To Moderate Temperature- Hot Water To High Temperature- Steam 2. Fluids for cooling the reactor or cooling fluids in Shell and tube heat exchanger Chilled water- 5-10 0 C Brine- -5-00 C Liquid Nitrogen- (-50 0 C) -(-100 0 C) 3. Simple water is used for washing the reactor along with mixing via agitator. Notes: 1. Steam used for heating the reactor is always passed from the top, if passed from the bottom contact time will be less and it will condense very soon. 2. Condensate is collected from the bottom of shell and tube heat exchanger as well as reactor’s jacket
1.2 Distillation Distillation is one of the most common liquid-liquid separation processes, and can be carried out in a continuous or batch system. It works by the application and removal of heat to exploit differences in relative volatility. The heat causes components with lower boiling points and higher volatility to be vaporized, leaving less volatile components as liquids. Mixtures with high relative volatilities are easier to separate. This makes separations of close-boiling and azeotrope feeds difficult, so special distillation techniques have to be used to separate these mixtures.
Columns: Batch- Column is connected with batch reactor and is used to recover product whose feed is charged batch wise at intervals. Continuous- No reactor is associated; feed is continuously charged into the column.
Column types: 1. Packed column Although packed bed columns are used most often for absorption, they are also used for the distillation of vapor-liquid mixtures. The packing provides a large surface area for vapor-liquid contact, which increases the column's effectiveness. Differences in BE CHEMICAL-2nd Year
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concentration cause the less-volatile components to transfer from the vapor phase to the liquid phase. The packing increases the time of contact, which increases the separation efficiency. The exiting vapor contains the most volatile components, while the liquid product stream contains the least volatile components. Type of packing1. Raschig / Structured sheet metal Packing This company has all the packed bed columns of structured sheet metal type due to its greater efficiency.
Honey comb like structured sheet metal packing/ Raschig rings.
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Outside of every distillation column is covered with glass wool which acts as insulation and prevents heat loss. Average height of each column used in industry was about 30 m (approx.). Solvent recovery plant had one continuous distillation system which used bubble cap column (tray/plate column). Each column had a glass on surface to view inside the column so as to maintain the level of liquid inside the column for distillation.
Tray/Plate column
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Bubble cap trays A bubble cap tray has riser or chimney fitted over each hole, and a cap that covers the riser. The cap is mounted so that there is a space between riser and cap to allow the passage of vapor. Vapor rises through the chimney and is directed downward by the cap, finally discharging through slots in the cap, and finally bubbling through the liquid on the tray.
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1.3 Agitators Connected to almost all the reactors except kettle reactors. It is used in solvent recovery because
For keeping homogeneous liquid bulk during storage.
It increases heat transfer
There are 4 types of agitators mainly1. Anchor 2. Turbine 3. Propeller 4. Gas induction In solvent recovery plant reactors were having propeller type agitators. In pilot plant glass lined reactors had anchor type agitators. The choice of agitator depends on the phase that has to be mixed (one or several phases).Depending on type and viscosity of the phase agitators can be named.
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1.4 Collectors/Receivers These are cylindrical tanks for storing the product or they can act as feed storage tanks too.
1.5 Phase separators These are semi-cylindrical conical tanks which are used to separate to liquids on the basis of difference in specific gravities of two liquids. It has good application in azeotropic distillation. Heavy liquid settles at the bottom and lighter one remains at the top and both can be separated by connecting lines at top and bottom of the phase separator.
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1.6 Rotameters It is a device used to measure the flowrate of a fluid.It regulates the flow rate in different lines.It works on the principle of buoyancy force.It has a cone shaped body know as float inside it which rotates contonuously.The top of the float reads the flow rate on the caliberated scale on the rotameter.
1.7 Level indicator It is simply used to measure the level of water inside a tank .It works on the principle that pressure is same on the same level for an incompressible fluid.
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1.8 Pumps Pumps are devices used to transport fluid from one place to another. There are many kinds of pumps used in this pharmaceutical industry based on their applications at different places. Centrifugal pumps It uses impellers to push fluid from one place to another. It is most common used pump in the industry. Vacuum pump It is used to create vacuum or suction by removing the gas molecules from the sealed volume. It is used at all places where product recovery is under vacuum. Rotary pump This pump is being used in this industry in tube settler in Effluent treatment plant (ETP).
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1.9 Valves It is a device that regulates directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Different types of valves were used in the different plants as per the requirement.
Ball valve It was the most common used valve in the plant. Almost all the lines were monitored by ball valve in the solvent recovery plant. It offers very good shut -off capabilities. Butterfly valve I saw butterfly valve in multi effect evaporator plant and R.O. plant. It has a lever and flow is regulated through a disc-type element held in place in center of the valve by a rod. Globe valve It is S-shaped valve. These were rarely seen in the industry (hardly one).It is used just for the flow rate control. Gate valve Most of the lines coming from utility block had gate valves. Steam lines had gate valves. Flow is controlled by raising or lowering the valving element. Their operation time is longer as compared to the others.
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CHAPTER 2 Solvent Recovery Plant
This plant is designed to extract the valuable and useful chemicals from the mother liquor obtained from various sites.
Separation of pure compounds and sending them back to their site of application.
2.1 Operation/ProcessDMSO Recovery (Dimethyl sulphoxide) PropertiesDensity=1.1 g/cm 3 Molecular mass= 78.13 gm Boiling point= 189 0 C
Procedure 1. Feed is charged into the reactor via lines and the feed is a mixture of DMSO, toluene and water. Toluene-water is recognized as impurity and we have to extract DMSO from the mixture as it is valuable and costly too. 2. Separation technique employed here is distillation in which separation is done on the basis of difference in boiling points of different liquids in the mixture. 3. Feed is now heated via steam. Now, for low boiling liquids steam is enough to vaporize the liquid but for very high boiling liquids we require very high amount of steam which may cause problems like bursting of reactor. So the concept of negative pressure is applied.
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4. Negative pressure - Recovery of DMSO is done under vacuum as it is a high boiling liquid, we create vacuum inside the reactor using vacuum pump which results in increased boiling rate. Condition for boiling is: Vapor pressure > Atmospheric pressure So when the vacuum is created, there is no air and atmospheric pressure is zero h ence vapor pressure increases automatically and boiling takes place at lower temperatures. 5. Toluene-water is low boiling as compared to DMSO, so they vaporize together and the vapors flow through column and enters shell and tube heat exchanger to get con densed. The condensate contains toluene-water and DMSO both as DMSO vapors are also present during vaporization. So reflux line is started to increase the purity of product or to allow the molecules of only one type to vaporize. So, only the molecules of t oluene-water vaporize not DMSO. This is determined by the top temperature of the column when reflux is started. Top temperatures determine whose vapors are being vaporized and according to that the process is monitored. After the steady state is achieved r eflux is shut off and condensate is collected via collector line. 6. In this recovery toluene-water is collected first in a phase separator. Toluene and water has different specific gravities, hence they are separated in the phase separator. Toluene remains at top and water settles at the bottom. Both can be separated this way. 7. Now only DMSO is left in the reactor which is again vaporized, condensed and collected in the recovery tank in the same fashion. Residual mass from the bottom of the reactor is collected through the line at bottom of the reactor. 8. In this SRP, recovery of other products like Methylene dichloride (MDC), Methanol also takes place in the exactly similar way, the difference is that few of them are low boiling liquids so there is no need for vacuum in the reactor, steam is sufficient to vaporize the liquid. 9. This kind of distillation can be placed under the category of vacuum distillation.
2.2 Azeotropic Distillation
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1. Azeotrope - a mixture of two liquids which has a constant boiling point and composition throughout distillation. 2. Azeotropic distillation is technique used to separate azeotropes which is very difficult job by other methods. 3. In this SRP, they have two kinds of azeotropic distillation - batch and continuous and they separate IPA-water by using both the ways. IPA (isopropyl alcohol)
Water
Cyclohexane
C3H8O
H2O
C 6 H12
786 kg/m 3
1000 kg/m 3
779 kg/m 3
B.P- 82.6 0 C
B.P- 100 0 C
B.P- 80.74 0 C
4. In this process addition of another substance takes place to produce low boiling azeotrope to facilitate easy separation. 5. In this plant, since there is separation of only IPA-Water, this is achieved by forming low boiling azeotrope by adding cyclohexane.
Azeotrope data
IPA-Water
B.P = 80.4 0 C
CHN-Water
B.P = 69.8 0 C
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Batch system 1. Feed is charged into a reactor which is driven with the help of propeller -type agitator and steam is passed into the jacket. 2. Feed contains IPA-water mixture and CHN is added along with feed. Cyclohexane lowers the water from IPA and makes a low boiling azeotrope with water. 3. Reboiler is connected along with the reactor to increase the vapor load. Vapors flow through column into STHE and get condensed .These are the vapors of CHN -Water as it is a low boiling azeotrope and IPA is left behind in the reactor. Condensate is collected in a phase separator in which CHN and water separate as they have different densities. Water settles at the bottom and CHN is collected in a different tank. 4. During vaporization there are vapors of IPA along with CHN-Water azeotrope, so to increase the purity of the product CHN is refluxed back into the reactor so that only CHN-Water vaporize. After this the reflux is shutoff and collector line is turned on and CHN-Water is collected and separated. 5. Only pure IPA is left in the reactor which is vaporized and collected in the recovery tank in the same manner. Residual mass is collected from bottom of the reactor and is disposed.
Continuous system 1. This system is divided on the four floors in the SRP. It is operated for at least 20 hours a day. There is feed tank present at the top floor which contains IPA-Water mixture. It is charged in the reactor using four inlets 2. Bottom of the column is connected with a reboiler to increase vapor load or rate of vaporization. Feed is vaporized and vapors flow through column at second floor to condensers present at the top floor. Currently two condensers were functioning. Finally
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condensate i.e. IPA-Water mixture falls in the decanter placed at second floor which is connected by a feed line of Cyclohexane which comes from CHN tank placed at top floor. 3. Reflux is provide from top of column into decanter and top temperatures tells the time for which reflux has to be maintained. Once the reflux is complete, it is proved that only pure IPA is present at the bottom of the column and a line from bottom of the column is given into STHE which is referred to as product cooler and then pro duct after cooling is collected in recovery drums or collection tanks. 4. IPA-Water mixture present at the bottom of decanter is collected in different tank which can be again used for recovery of pure IPA. 5. Column used in the continuous system here is bubble cap tray column. Reflux is shut off when temperature at top is 60-650 C and temperature at the bottom is 82.5-82.7 0 C.
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CHAPTER 3 3.1 Reboiler 1. Reboilers are basically Shell and tube heat exchangers which are placed vertically. 2. Reboilers are connected to increase the vapor load which results in fast distillation or fast rate of vaporization. 3. Solvent is sent into the tubes of Reboiler and steam is passed into the shell which vaporizes the solvent in the tubes. 4. Condensed steam is sent back to the utility block for applications like use in cooling tower etc. Top line of reboiler is connected with column to allow vapors to flow together. 5. Vapors are produced from both reactor and reboiler resulting in greater concentration of vapors and make the process less time consuming.
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3.2 Safety and Precaution Measurements 1. Working in an SRP in a very risky and dangerous. Lots of things have to be kept in mind while operating a solvent recovery plant. 2. Accessories which have to be worn by workers while charging/discharging the tanks are I.
Gloves
II.
Nose mask
III.
Eye glasses
IV.
Face sheet
V.
Helmet
VI.
Apron
3. When the solvent is recovered in the recovery tank, its earthing has to be done so as to remove the static charge from the solvent which may cause fire and result in an explosion. Static charge: It is imbalance of electric charges within or on the surface of material. The charge remains until it is able to move away by means of electric discharge. It is created when two surfaces come in contact and separate and at least one of them has high resistance to current. 4. Earthing of solvents is done to discharge the entire static charge with the help of a green wire through which all of the charge is discharged into ground.
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Cause of fire Fire is caused on completion of this triangle. If any one of these is absent fire will not be caused and if by mistake three of them are simultaneously available, it will cause an explosion which destroys everything.
In case there is fire in the plant then there are various saf ety measures which can be taken: 1. Using Fire extinguisherNow there are five types of fire extinguishersFire extinguisher
Contents
Type of fire
A
H2 O,CO 2
Clothing fire, wood etc.
B
Foam DCP, CO 2
Solvent fire
C
DCP, CO 2
Gaseous substances
D
Sand, DCP, CO 2
Metal fire (K,Mg,Al)
E
DCP, CO 2
Electrical appliance
DCP-Dry chemical powder
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2. AFFF (Aqueous film forming foam) can also be used to suppress fire. Its role is to cool the fire, coat the fuel, preventing its contact from oxygen resulting in suppression of combustion. 3. Fire hydrant system These are very large diameter piper which contain gallons of water and release water at extremely high pressure which helps in suppression of fire. These pipes are of red color and are very lengthy. 4. Fire alarm system When fire alarm is turned on, immediately the industry gets to know that in which plant fire has occurred. As soon as they know fire brigade is called immediately to that plant site. 5. Sand (Silica) Sand is kept in the buckets at the plant site so that it can easily be put in case of any fire.These are called fire buckets. Sand cuts the supply of oxygen to fire.
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CHAPTER 4 Pilot plant
Process/Plant Overview
Reaction
Distillation
Crystallization
Centrifuge/Filtration
Drying
Finishing of product
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4.1 Reaction The reaction was taking place in a glass lined reactor as solvents were acidic in nature. Agitator used in the reactor was anchor type agitator. The process I mention in my company is actually patented by them and no other pharmaceutical company can use th is recipe. Reaction is done by charging the feed which contains –Toluene, XYZ, Tetra butyl, Bis-trimethyl, Acetic acid. These chemicals are feeded into the reactor and are agitated for at least 3 hrs with help of anchor type agitator.
4.2 Distillation Toluene is distilled out and collected in a separate tank whereas other chemicals are left behind in the reactor as thick residual mass in which solvents are added to liquefy it. Isopropyl alcohol, sulphuric acid and water are added which keeps the pH 2 -3, again it is agitated and the temperature of the reactor is lowered to 5-10 0 C.
4.3 Crystallization Crystallization takes place which results in two things- Mother liquor and crystals mass. Mother liquor is again sent to SRP for solvent recovery and the crystals are further processed.
4.4 Centrifugation/Filtration Material is sent for centrifugation from where mother liquor and solid mass are separated. Centrifuge is rotating at the speed of 1440 RPM and it contains a bag filter basket at the top which is 5 µm (microns). This helps in collecting the weight materi al and liquid is sent to SRP.
4.5 Drying These crystals are now sent for drying. This company has two types of dryers –Steam bed dryer and vacuum bed dryer. Vacuum bed dryer is rarely used; generally steam bed drier is used for drying the crystals. Once the crystals are dried product stage XYZ is achieved .After this final finishing is done.
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4.6 Finishing Finishing results in production of final stage i.e. ABC which is sent to market or customers. Finishing consists of many steps as followsI. Blending: It is mixing of other chemicals to enhance desired properties of the product. II. Carbon treatment: It is done to remove undesired color from the product. III. Sparkle filter: It is used to remove left contaminants in the product. IV. Humidity, Moisture content, pH, Air content are maintained in special chambers so that quality of product does not change. V. Micronizing: It is done to reduce the size of product into finer particles. N ow currently the company is producing the product at X microns in the pilot plant. The size reduction takes place with the help of mesh which they call milling.
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CHAPTER 5
MEE-Multi effect evaporator ETP-Effluent treatment plant RO-Reverse Osmosis
Notes: 1. When the processes complete in all the plants of the industry, they are left with mother liquor which might be contaminated water or water-solvent mixture. 2. If mother liquor contains useful chemicals which can be extracted are sent to solvent recovery plant and the left contaminated water is sent to Environmental plant. 3. Environmental plant classifies water on two parameters which are TDS (Total dissolved solids) and COD (Chemical oxygen demand).
Feed (Contaminated water)
Low TDS
ETP
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High TDS
MEE
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5.1 Multi-Effect Evaporator (MEE) 1. It is used to treat high TDS water. Feed is charged into a balanced tank. This plant operates about 100kl of water every day. 2. This company has 5 effects but normally 3 are in use, if load is more other 2 can also be operated simultaneously. 3. Effects are also known as calandria and each calandria is provided with preheater to preheat the feed and a vacuum pump as entire recovery is under vacuum. 4. MEE works on the principal of less usage of steam, only few Kiloliters of steam can be used to treat many kiloliters of water. 5. Steam is only fed to first calandria, the vapors of the feed travel to jacket of second calandria as they are hot. The vapors have sufficient heat to vaporize the feed in second calandria, similarly the process is continued till last effect. 6. Concentrate from the bottom of each effect is fed to consecutive effect by lines. This way all the concentrated liquor goes to last effect and the vapors of feed present in the jacket of last effect are sent to a shell and tube heat exchanger and the condensate is further sent to stripping section. The vapors that get condensed in the jacket of each effect are also sent to stripping section. 7. Condensate from all effects has very less TDS i.e. in the desired range but it has high COD, which is removed with the help of a stripper. Stripping is done in the column where all the COD is evaporated using steam and the COD free water is collected in the tank and sent to utility block for use in cooling towers, toilets etc. 8. Now the last effect contains all the concentrated liquor from all the previous effects. This slurry is fed to ATFD (Agitated thin film drier). ATFD is a semi-cylindrical conical shaped machine in which feed enters and evaporates the water and dries the concentrate with constant agitation and left residual mass is converted into powder or flakes. 9. This company has done a time savage effort in MEE by installing a reactor nearby ATFD. As ATFD requires time for cleaning so by the time reactor can be utilized. The BE CHEMICAL-2nd Year
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feed is put in the reactor, reactor evaporates the water and the residual mass is collected from the bottom and sent to ATFD for drying. 10. The solid waste or the powder obtained from ATFD is non-incinerable. There is no process to treat that solid waste and all this type of non-incinerable. solid waste from the entire industry is packed in the polybags and sent to NIMBUA plant (a landfill). I have also covered Nimbua plant as a part of my internship.
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5.2 Effluent treatment plant (ETP) Low TDS water is sent to ETP for treatment and water is processed here in many steps one by one. There are three stages –Primary, secondary and tertiary. Primary Treatment I.
Oil and Grease trap- These are tanks which contain metallic traps on which effluent is flown. They are used to reduce the amount of fats, oils and greases from the effluent.
II.
The water from grease trap is sent to three tanks which work on shift basis. Here manual addition of chemicals takes place: i.
Caustic is added to take the pH of water to 9-9.5 and there is a reactor placed on side of tank when solution of caustic and water is prepared and then it is charged in the tank.
ii.
Alum is added to reduce the pH to 8-8.5 as reduction of pH helps in breaking of bonds in the water and create flocs. This helps in separation of suspended impurities from water.
iii.
Polyelectrolyte is added to water which settles all the flocs and clear water is above. Air is passed in the tank through bottom to facilitate proper mixing.
Note: The water free from suspended impurities is sent into thickener (settler) which results in formation of two zones- Clear water and Sludge. The sludge is sent to drying beds where drying takes please in the open atmosphere. The dried sludge is packed in drums and sent to Nimbua plant for solid disposal. Clear water from thickener is sent for secondary treatment or biological treatment into bio towers.
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Secondary Treatment 1. Clear water from thickener is now sent into bio towers where most of the BOD/COD is removed. Bio towers have packing in them which have bacterial growth culture in it. This bacterium eats all of COD/BOD. Here bio tower functions in two ways – i. ii.
Low volatile solvents are reduced as they get vaporized in the air. Removes BOD/COD from the effluent.
2. Water from bio tower is sent to the two aeration tanks one by one where aerobic oxidation takes place that degradation of contaminants present in water with the he lp of bacteria in the presence of sunlight. There are two aeration tanks of capacity 450 and 250 liters respectively. The slurry from both the aeration tanks is sent to thickener from where clear water is sent to anaerobic tank and sludge from bottom of thickener is sent to sludge drying beds. Now the water is sent to anaerobic tank which is covered from outside and degradation by bacteria takes place in the absence of sunlight. This is known as anaerobic treatment. 3. Finally the water is collected in the tank and sent to R.O. (Reverse Osmosis) plant for tertiary treatment.
5.3 R.O. (Reverse Osmosis) Plant To meet the strict requirements by pollution board and to control the parameters tertiary treatment has to be provided to water after the biological treatment. Tertiary Treatment1. The water after aerobic and anaerobic treatment contains bacterial sludge in which bacteria keeps on multiplying, so undesired parameters are increased. For this reason tertiary treatment is given. 2. There are two tube settlers in which the bacteria is killed and removed by addition of chemicals. Alum acts as antibacterial and flocculent.
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3. Polyelectrolytes are added to settle the flocs in the tube settlers and the remaining water is passed through multi-grade filter and carbon filter to remove other impurities and color from water. 4. From the filters, the water is sent to ultrafilter for ultrafiltration which contains tubes of diameters in microns. From here water goes to feed tank and finally into RO. 5. R.O. works on the principle of reverse osmosis and contains semi-permeable membranes and this plant had three cylindrical RO’s and water from these is very clean and colorless which meets the requirements of pollution board too. Still this water is not used for drinking purpose in the industry as it may have ppm concentration of harmful chemicals. So it is rather used in cooling towers, toilets, utility block etc. 6. The sludge collected from all the tube settlers or thickeners is sent to sludge drying beds for drying but this is a very time consuming process. So, they have installed a filter press to facilitate fast drying .
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Solid waste treatment The solids left as waste from various plants of the industry can be broadly classified in two categoriesIncinerable and Non –Incinerable The solid waste which can be burnt is known as Incinerable waste and the waste which cannot is known as non incinerable waste. The waste from industry which cannot be burnt is packed into bags and sent to Nimbua plant for disposal and rest which can be burnt is sent into Incinerator.
5.4 Incinerator 1. Solids which have high heat capacities give high amount of heat on burning, so to control the heat they are mixed with solid material of low heat capacity. 2. This mixture is the feed and it is kept in a pit which is connected to a conveyor belt which has cup like cavities used for transporting material from bottom to top. 450kg/hr. of solid can be transported by conveyor belt. 3. The solid is fed into primary combustion chamber (PCC) which is at 850 -8600 C. Air is pumped from the side to distribute the solids in entire furnace for combustion of solid. First furnace is connected to second furnace in which fumes from first furnace en ter. Diesel is used to heat the second furnace and the temperature is 1100 0 C. 4. The fumes from second chamber go to a 5 ton boiler in which cooling lines are attached from the utility block. Cooled fumes now pass through a dust collector which collects dust into a bag at bottom and fumes through top goes to scrubbers. Cooling fluid used here is soft water as it prevents scaling in heat exchanger (boiler). 5. There are two scrubbers placed simultaneously and each scrubber has a caustic tank with it. Caustic tank consists of caustic-water mixture which is sprinkled from top of
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scrubber. Scrubbers consist of packing which facilitate efficient vapor -liquid contact. Fumes enter the first scrubber through bottom since fumes contain NO X and SO X gases, these are neutralized by caustic water and condensate is collected at bottom. Left fumes go to second scrubber where same process takes place. 6. The fumes from second scrubber are free of harmful gases, it is very clean. These fumes are sucked up by Induced Draft Fan and are sent out in the atmosphere through chimney. Length of chimney was around 30m. 7. The condensate present at the bottom of the scrubber tanks is sent to collection tanks from which it is sent to ETP for treatment and the left sludge is dried in beds , packed in polybags
and
sent
to
Nimbua
plant
for
disposal.
8. There was one more furnace which was meant for charging the solvents, which were charged with a material which melts easily and it is kept in the tray. Ash is collected from left hand side opening of the furnace and this furnace is connected to first furnace too. 9. Each furnace was connected to Forced Draft Fan which sucks air and provides oxygen for combustion. Ash is collected from each furnace from bottom opening and this ash is packed in polybags and sent to Nimbua plant for disposal. NoteSTHE or Boiler contains that fluid inside tubes which cause scaling because it is easier to clean tubes as compared to shell.
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CHAPTER 6 Quality Control and Quality Assurance Department
1. Quality control is one of the key departments in the pharma industry. After R&D large number of people works in QC dept. 2. A chemist executing a qualitative analysis seeks to identify the substances in the sample. A quantitative analysis is an attempt to determine the quantity or concentration of a specific substance in the sample. 3. This department takes care of the quality of the product and assures the desired product to the customers. Instruments use in the QC department of this company are
HPLC (High performance liquid chromatography)
XRD (X-Ray Diffractometer)
IR (Infrared Spectrophotometer)
Polari meter
UV spectrophotometer
Stability chambers (Humidity control)
G-C (Gas chromatography)
Karl Fischer Apparatus
AAS (Atomic absorption spectrophotometer)
IC (Ion chromatography)
UPLC (Ultra performance liquid chromatography)
Potentiometer, pH meter, Conductivity meter, dissolution operator, Mill -q water purification system.
Cold lab chamber
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Note:
The solid waste generated from any company in the end has to be disposed somewhere, it cannot be just thrown out anywhere in the society because that solid contains hazardous and toxic chemicals which will disturb the neatness and biological system of the environment.
That solid waste coming out from any industry goes to a Common Hazardous Waste Treatment Storage Disposal Facility (CHWTSDF).
Each state has one CHWTSDF for taking care of all the hazardous solids coming from various sources.
At the facility, all directions of CPCB (Central pollution control boa rd) and SPCB (State pollution control board) are being followed in letter and spirit to ensure a cleaner environment by proper handling and disposal of hazardous waste.
Since my internship was in Ind-Swift laboratories ltd which is a Punjab based company, so I visited the CHWTSDF of Punjab state which is second phase of my internship program .
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CHAPTER 7 Nimbua Greenfield Punjab Limited (NGPL)
It is a project promoted by nine companies of Punjab in collaboration with Punjab pollution board and government of India.
Project was implemented for developing a hazardous waste management facility to treat and dispose hazardous waste generated by various industries in Punjab.
The facility is located at Nimbua village, district Mohali, Punjab.
The facility is provided and installed by the nine companies in collaboration with Punjab pollution control board and government but it is operated by some contractor. Punjab government issues the tender to a contractor which will run the treatment facility.
Presently the facility is operated by Ramky Enviro Engineers Ltd. It is a Hyderabad based environmental company which has presence in industrial, biomedical and municipal waste management all over the India. It was selected to design, operate, execute project at Nimbua by a Technical committee.
Presently there are 1889 industries from Punjab which are registered at Nimbua plant for solid disposal.
Procedure 1. Waste is transported from the industry to the plant by following transportation norms. 2. Waste is categorized on different basis-like Incinerable and Non-Incinerable. 3. Now, waste is sent for comprehensive analysis by which the procedure for waste treatment is determined. 4. Different kinds of wastes are stored in different sheds in suitable conditions as per CPCB guidelines.
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5. Incinerator was functioning in the same way as I explained above. They mix high heat capacity solids with low heat capacity solids and then they feed it in the incinerator. 6. Wastes which do not contain much harmful chemicals or they are as per pollution norms are sent directly to the landfill. 7. Wastes which are not as per pollution norms are pretreated so as to put parameters in control before landfill. 8. After treatment the waste is sent to landfill for disposal. 9. Each sample of waste by any company is preserved by the lab operators so as to claim the same results after years of disposal, in case company complaints about the method of disposal.
7.1 LANDFILL
Landfill is a big ground or place where all the solid waste after treatment is dumped.
There are two types of landfills- Open landfill and Secure landfill. This facility has secure landfill.
Bottom of landfill is few meters above the groundwater so as to prevent groundwater from contamination.
At the bottom of landfill, there is gravels and soil, when solid waste is completely dumped, if there is any liquid, it passes from the bottom and gets collected in the sumps provided in the landfill.
Sumps in the landfill are connected to Multi-effect evaporator, where the water from bottom of landfill is transported via lines, evaporated and solids are collected separately.
Water from MEE is reused for cleaning transport vehicles etc. and this way all the water is removed and only solids remain in the landfill.
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The landfill is covered with the help of a Polyliner which is imported from Saudi Arab and this liner has perforated structure inside which helps the water to go in the sump.
Presently there are 4 pits where solids are dumped. Two of them are completely filled and two of them are being filled and probably these two will be filled in upcoming 15 years.
A pipe is connected as an open line to the landfill after covering it with polyliner so as to remove all the gases generated by the solid.
Landfills are very efficient and cost effective methods for treatment of solid waste generated from the society or industries.
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CHAPTER 8 Shell and Tube Heat Exchangers Shell and tube heat exchangers are most common type of heat exchangers used in the industry. They contain large number of tubes and a shell in which heat transfer takes place. One fluid flows through shell and the other through tubes. They contain baffles for uniform distribution of fluid across the shell. Shell and tube heat exchangers are further classified according to the number of shell and tube passes involved. Heat exchangers in which all the tubes make one U -turn in the shell, for example, are called one-shell-pass and two tube-passes heat exchangers. Likewise, a heat exchanger that involves two passes in the shell and four passes in the tubes is called a two-shell-passes and four-tube-passes heat exchanger. In this industry there were all the types of heat exchangers and luckily I found a heat exchanger open and it helped me to analyze the flow of fluid in the tubes and shell which is discussed below. The reason that maintenance people had to open the condenser was that one of the tubes was leaking from the condenser. Solution of the problem was that they inserted an iron rod in the tube so as to block the leaking tube. There were total 108 tubes divided by four passes, 27 in each pass. Flow in the heat exchanger can be categorized in two ways -parallel and counter flows. Flow in which cooling fluid and product flow in the same direction is called parallel flow and if in the opposite direction, then it is called counter flow. Efficiency of parallel flow is less as compared to counter flow, so STHE have counter flow generally. The STHE which I analyzed was fixed tube type heat exchanger.
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8.1 Shell and Tube Heat Exchanger Analysis- a mini project
It is a calculation based analysis of shell and tube heat exchanger placed in SRP. I have used LMTD method and NTU effectiveness method for obtaining and comparing results. Outcome will not be accurate but fairly approximate which gives us an idea about applying theoretical concepts in real systems.
Hot fluid- Cyclohexane-Water azeotrope Cold fluid- Cooling Tower Water TemperaturesTHot in =65 0 C
THot out =45 0 C
TCold in =34 0 C
T Cold out =38 0 C
Volume flow rate of hot fluid= 1000 l/hr Azeotrope fraction- 0.3 CHN 0.7 Water C p of H 2 O at 55 0 C = 4.0658 J/gK C p of Cyclohexane = 1.5 J/gK C p of Azeotrope mixture = (4.0658)0.3 + (1.5)0.7= 2.26974 J/gK So, C p hot fluid = 2.26974 J/gK C p cold fluid = 4.0682 J/gK (at 36 0 C average temperature) using fluid property calculator
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DensityCHN- 779 kg/m3 H2O – 985.3 kg/m3 Azeotrope =(779)0.7+(985.3)0.3 = 840.89 kg/m3 Mass flow rate becomes= 840.89 kg/hr Q̇ hot = M . C P (T Hot in - T Hot out ) Q̇ hot = 840.89 *2.26974*(65-45)=10.603 kilowatts. For heat balance, Q̇ hot = Q̇ cold So, Q̇ cold =M c C P (Tcold out - Tcold in ) 10.603= M C (4.0682)(38-34) M C =2345.68 kg/hr Now, according to LMTD method Q̇ = U*AS*(F*T diff ) Tlm = (T2 -T1 )/ln(T 2 / T1 ) R = (t 1 -t 2 )/(T 2 -T1 ) = 0.200 P = (T2 -T1 )/ (t 1 -T1 ) = 0.6452 F = 0.9546 LMTD = 17.8185 Corrected LMTD = (0.9546)*( 17.8185)= 17.0091 Since, Q̇ = U*A S*(F*T diff) Q̇ = U*AS*(17.0091)
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10.603= U*A S*(17.0091) Now, we don’t have AS and U, so we have to find a method. According to cleaning worker of STHE, this STHE had 48 tubes, 20 mm diameter of each, 5ft height of the HE. Based on this information we can find A S. So, AS = 48*(2*3.14*0.01*1.524)= 4.5939 m 2 Curved surface area is used i.e. = n*2*pi*r*L n= number of tubes for heat transfer r=radius of each tube L=length of HE Now, 10.603= U*4.5939*(17.0091)
U=135.69 W/m2K
Verification of results obtained using NTU effectiveness method Finding the heat capacity rates C h =M Hot Cp= (840.9)*(2.26974) =530.17 W/K C c =M cold Cp= (2345.68)*(4.0682) =2650.7 W/K C min =min (C h , C c ) C min = 530.17 W/K Q̇
max
= C min (THot in - Tcold in )
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Q̇
max
= (530.17)*(65-34)= 16.435 kilowatts
Now to find the effectivenessTwo values are required = NTU and c NTU (number of transferred units) = (U*A S )/ C min C (capacity ratio) = C min / C max NTU = (135.69*4.5939)/530.17 = 1.17 C = (530.17/2650.7) = 0.2 Expression for calculating effectiveness –
Substituting these values in the expression, we get effectiveness as e=0.7527 Now, Q̇ So, Q̇ But Q̇
actual
actual
= e* Q̇
max
= (0.7527*16.435) = 12.37 kilowatts
actual
obtained from LMTD method was 10.603 kilowatts, hence there is error in
calculation.
% Error = {(12.37–10.603)/10.603}*100 % Error = 16.67 %
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According to a website on internet, if in a shell and tube cooler, cooling fluid is water and hot fluid is organic solvent, then the values of U lies among 250-750 W/m 2 K Now suppose the U= 700 W/m 2 K for the same heat exchanger then, after this equation10.603= U*A S*(17.0091) Substituting U as 700 W/m 2 K, We get AS =0.89 m 2 Now, Area of one single tube = 2*pi*r*L As for one tube comes out to be = 0.0957 m 2 So, for this value of U, number of tubes required in the same HE for same rate of heat transfer will beN= (AS,total / A S,one tube ) N= (0.89/0.0957) = 9.29
Number of tubes required at least = 10
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CONCLUSION
This summer internship was most amazing time of my career as a chemical engineering student till now.
It helped me to get the overview of an industry.
Familiarity with industrial culture, working, record maintenance, documentation work etc.
In depth knowledge of equipment used and skills of operating a plant whether it is an SRP, Pilot plant, ETP, MEE, RO, Incinerator, QC or CHWTSDF etc.
A comprehensive study on the working of shell and tube heat exchanger was also offered during the course by the mentor.
Basic necessities were taught here which are important for a person to follow while visiting a plant.
This company specifically provided me a chance of understanding each and every plant working/processing in detail.
After this internship, I am pretty much confident to go out in any kind of industry and work there as a chemical engineer.
This internship taught me important things like discipline, time management and communication.
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REFERENCES
[1]Cengel, Yunus A. (2010). Heat Transfer: A Practical Approach, 7th ed. McGrawHill.
[2]Seader, J.D. & Henley, Ernest J. (2006). Separation Process Principles (2nd ed.). John Wiley & Sonstahm. [3]Fogler, H. Scott (2006). Elements of Chemical Reaction Engineering (4th ed.). Prentice Hall. [4]"Midden". Merriam-Webster. Retrieved 18 May 2014. [5]"Alternative Daily Cover (ADC)". Retrieved September 14, 2012. [6]"LFG Energy Projects". United States Environmental Protection Agency. RetrievedFebruary 21, 2015.
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APPENDICES
Appendix A1- Azeotrope data VLE-Calc.com Appendix A2- Azeotrope data by Dortmund data bank Appendix A3- Azeotrope data by chemistry.mdma.ch Appendix B1-Molar heat capacity by Dortmund data bank Appendix C1-Overall heat transfer coefficient values by engineeringpage.com Appendix C2- Overall heat transfer coefficient values by Blackmonk.co.UK
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