De-Dusting System.

In this presentation i have made the design and development of De-Dusting system for the reduction of dust and chemical emission from the atmosphere of the steel industry (Electrotherm India Ltd.) [Final Semester project Mechanical Engineering 8th sem]

1. Major Project Final Review Name : Vivek Mitra Roll NO: 14bme160 Guided by : Prof. shebaz memon

2. Content Literature review Identification of problem Emission of dust and chemicals What is De-dusting system Calculations Fan Efficiency RMHS System Checking of the ID fan capacity

3. Project Title Design and Development of De-dusting system.

4. Literature review Development in the dust reduction technique have been done by many engineers and how to reduce the dust from the plant is continuously improving. At first the dust from the foundries and the steel industries were removed or minimized with the help of the exhaust fan or blower or huge fans. A nd with this the development of the bag filter dust collection carried out, with day by day increasing the demand for higher efficient dust removal.

5. Literature review This system works on the basis of bag filter dust collection, where the induced draft fan Is used for the suction of the dust from various dust generating points. The different points are provided for the suction of dust and the header and the suction pipe from the main point is connected to the header and thus that dust than goes to the bag filter dust collection chamber. Now when the dust and the fine particles are there in the chamber then there are different filter bags provided in which the long cage around 2500 mm length is there.

6. Literature review The cage is provided with the fiber cloth mostly used material is P.T.F.E (polytetrafluoroethylene) whose resisting temperature is 326.8  °C. N ow when dust enters the chamber then it goes to the filter bag and sticks there. below these bags the hoper section is there and beneath the hopper there is valve which discharges the dust and the other particles.

7. What is De-Dusting System. The De-dusting system works on the basis of the induced draught fan. The ID fan is connected with the ducting system. The ducting system/header is generally 250-300 mm diameter pipe and that is connected through the different suction points. The different suction points are the one which are situated over the different discharge points over there the raw material is discharged. Further the ID fan outlet is connected through the chimney for the exhaust of gases to the atmosphere.

8. Identification of problem The process discussed above is for BF2 and the same process is for BF1 but the RMHS system is open to atmosphere for BF1. In BF1 the material from ground is discharged to the RMHS building which is at 4 th floor (12.58m) height. The raw material is discharge at top floor through belt conveyor. The building consist of 4 big hopper and these hopper consists of different raw material according to the requirement of every day. The hopper generally 2 hopper of COKE and other two are iron ore.

9. Identification of problem The material is discharged at the top floor and that contains the shuttle trolley. The trolley is moved according to material onto which it is to be discharged. At the time of discharge the dust which is generated from the material when it falls is very high and the visibility is zero at this time. And due to this the discharge is done at morning, then at noon, and at night.

10. Emission of dust and chemicals Picture of RMHS D ust and Chemical emission while charging the material in Hopper

11. Identification of problem And when the hopper is fully filled then it is further discharge through the vibro-feeder which is at 2 nd floor and due to vibration the dust and chemical emission is very high and technician can not stand near there. Beneath the vibro-feeder there is screen which separates the undersize and oversize material and the required size material to the bottom conveyor which is ground floor. And the fines are generated so that is discharged to the fines centre which is done through conveyor (the dust from the fines is also high).

12. Front View of Raw Material Handling System

13. Identification of problem Now as discussed earlier the two hopper are for Coke. And the coke is preheated for this the section is made in the coke hopper section and the hot air at temperature of 250 degree Celsius. And which is running 24 hrs due to this the dust and fines of coke are generated very high and the temperature is very high at this time. So this is the problem which is required to minimized or controlled. After discussing this problem with concerned guide in industry we have decided to develop the De-dusting system for the raw material handling system for BF-1 plant.

14. Different Components of De-Dusting System Bag Filter Header (Pipe) Chamber containing Bag Filter Chimney Centrifugal fan/ Induced Draft Fan Butterfly valve

15. The working principle of bag filter Dust contained gas will enter into the upper side path hopper. In the screen board action of air flow up, reduce the flow velocity the part of the big particle inertia force due to the role of dust be separated into hopper. Dust contained gas enters into the bag filter in the filtration purification, dust sticks in the outer surface of the filter bag. As the filter bag dust surface increases and filter import and export with differential pressure rise.

16. The working principle of bag filter As the filter bag dust surface increases and filter import and export with differential pressure rise. Pulse is a key components of pulse bag filter. Its service life is the user of the concerns of problems.

17. Air Purification Principle

18. Calculations. The darcy-weisbach equation is used for calculating the pressure loss in a cylindrical pipe of uniform diameter D, ΔP =Pressure Drop. F =Pipe friction Co-efficient. L =Length of pipe V =Mean Velocity. D =Pipe Diameter. ΔP= flV 2 /2gd.

19. Calculations. f =2.738 L =20.650 m V = 30 m/s (taken by organization) D =0.3 m ΔP = 8645.214 Pa ΔP = 0.0864 bar ΔP = 2.738 x 20.650 x (30) 2 / 2 x 9.81 x 0.3

20. Calculations. Now, the capacity of ID fan which is there in the Electrotherm is 20,000 Nm 3 /hr The fan power requirement is to be calculated P = dp x q Now, P = 0.5 x 10 5 x 5.555 P = 277,777.77 (W) P = 277.77 (kW) Where P i = power consumption (W) Dp = total pressure loss (Pa) Q = air volume flow (m 3 /s)

21. Calculations. The motor HP required is obtained from the manual of the supplier [Rajdeep Engineering] is 40HP motor.

22. Fan Efficiency μ f  = dp x q / P   μ f = 0.958 or 95.8 % efficiency. Where, μ f   = fan efficiency (0-1) Dp = pressure (Pa) Q = air volume delivered by fan (m 3 /s) P = power used by the fan (W) μ f = 0.5 x 10 5 x 5.55/ 277.77 x 10 3

23. Front view Of plant Of RMHS System.

24. Checking of the ID fan capacity. There are in all 11 suction points from where the air and dust is to be sucked and they are not operating at the same time. Thus, the calculation is based on that, the simultaneous operation is 4 suction points at the same time. The suction points are as follows. Two at the top of the storage building from where the charging is done i.e. above the shuttle conveyor trolley there will be 2 suction points. Below the trolley there are 4 bunkers among them 2 bunkers are of coke and the other 2 bunker are of iron ore.

25. Checking of the ID fan capacity. From the shuttle trolley the material is discharged in the bunker and during this the dust emission is very high and so 4 suction points above the bunkers (these all are at 4th floor of the building i.e. at 11m from the ground). Then below that there is screen and vibrofeeder are installed in this area the required size is sent to the conveyor no 3 and the rest are sent to the fines conveyor which are under size

26. Checking of the ID fan capacity. The vibro-feeder and the screen section is located at the 4.30m from the ground and here also the dust emission is very high as the vibro-feeder shakes and separates oversize and undersize material therefore the dust emission is very high therefore here also 4 suction points are required to be given. Below that there is belt conveyor in which the material is discharged and that material goes to the belt no 4 this material is sent to the Blast furnace-1 and is discharged at the top of the furnace. And when the material is discharge in the B.C-4 then there is also emission of dust thus there also the suction point is to be give therefore in all total 11 suction points are provided.

27. Checking of the ID fan capacity. (velocity is assumed to be 25 m/s) Area= 3.14 x (0.3) 2 /4 (m) Area= 0.07065 m 2   Now, Q= Area x velocity Q= 0.07065 x 25 Q= 1.766 m 3 /s   And the calculated Q= 6358.5 m 3 /hr.

28. Checking of the ID fan capacity. Area= 0.8 x 1 Area= 0.8 m 2 And calculated Q= 2880 m 3 /hr .

29. Checking of the ID fan capacity. Therefore, the total simultaneous suction points are (Volume flow rate) Q= 6358.5 + 2880 + 6358.5 + 2880 Thus the required ID fan capacity i.e. 20,000 Nm 3 /hr. is justified. Total = 18,477 Nm 3 /hr.

30. The layout of the De-dusting system. 5 5

31. Design of Column and Hopper

32. Design of Chamber and air filter bag.

33. Design of Chamber and air filter bag.

34. Summary and future work

35. Summary of work After the first review the calculations and the required consideration for the De-dusting system have understood and concerned with the Internal guide about the things to consider for this system. Then the calculation of pressure drop and required fan capacity were carried out. After doing the calculation then according to the values the design consideration the layout of De-dusting System is made.

36. Future Work The organization Electrotherm Steel and Engineering India Ltd. have given assurance that they have accepted the design which I have made after considering various parameters and based on that design they are finding the supplier and the company who can fabricate this De-Dusting System.

37. Future Work The company have finalized the design and when I visited to the company the Mechanical Department of the Blast Furnace plant were deciding when to start the work on De-Dusting System for Blast Furnace-1 for Raw Material Handling System. The I.D fan Capacity is finalized and how much dust will be there in the air after this implementation of this system that work is in progress.