DESIGN MODIFICATION OFGAS CLEANING PLANT VENT SYSTEM

DEPARTMENT OF

MECHANICAL ENGINEERING

Submitted by :

MALLICHETTI.M (080111804026)

SATHISH KUMAR.C (080111804055)

SRINIVASAN.R (080111804059)

SHANKAR.P (090411804006)

GUIDE: CO-GUIDE:

E.JAMUNA S.MANIKANDAN

Asst. Professor Lecturer

OBJECTIVE

The making of iron in blast furnace, the impure gases coming from this process will

be poisonous. So that impure gases purified in the gas cleaning plant

During the purification of impure gases, the rupture disc on a gas cleaning system

get affected and burst because of top pressure.

The problem will be overcome with the help of pressure relief valve modification.

The pressure relief valve to be designed with materials compatible with many

process fluids from simple air.

The pressure relief valve will be modeled by PRO-E and performance of pressure

relief valve analyzed by ANSYS.

METHODOLOGY

SELECTION OF PROJECT

Company and area of the project chosen

PVT LTD Pottaneri, Mecheri, Salem.

STUDY ABOUT PROJECT

Overall view Blast Furnace plant

EXISTING SYSTEM

RUPTURE DISC

A rupture disc, also known as a bursting disc or burst diaphragm, is a non-

reclosing pressure relief device that, in most uses, protects a pressure vessel,

equipment or system from over pressurization or potentially damaging vacuum

conditions

IDENTIFICATION OF FAILURE

When top pressure of furnace exceeds the rupture disc burst (causes-Furnace slip).

Rupture disc get explode to relieve the excess pressure in the silos of the Gas Cleaning

Plant.

Once rupture disc failed it cannot be reused. New one has to be replaced

Hence we focus to replace the rupture disc into pressure relief valve

PROPOSED SYSTEM

PRESSURE RELIEF VALVE

Pressure Relief Valves is also know as safety valves, which is used to release the

excess steam when the pressure of steam inside the closed vessel exceeds the rated

pressure.

TYPES OF PRESSURE RELIEF VALVE

Hydraulic Pressure Relief Valve

Pneumatic Pressure Relief Valve

Spring Loaded

Dead Weight Pressure Relief Valve

DEAD WEIGHT PRESSURE RELIEF VALVE

DESIGN CALCULATION

1.Counter weight calculation by using free body diagram.

2.Design calculation for

lever

Pin

Shaft

COUNTER WEIGHT CALCULATION

From right angle triangle CDB, shown in fig

tan θ = BD/CD

tan45 = BD/275

1 = BD/275

BD = 275mm

Then using Pythagoras theorem, we get

CD2 + BD2 = CB2

2752 + 2752 = 388.92

Therefore…..

CB = BC = 388.9mm

From right angle triangle ABC, shown in fig

tan θ = BC/AB

tan45 = 388.9/AB

1 = 388.9/AB

AB = 388.9mm

Then using Pythagoras theorem, we get

AB2 + BC2 = AC2

388.92 + 388.92 = 5502

Therefore…..

AC = 550mm

Pressure (P) = Load/Area (Refer [1], P.G - 573)

Load (w) = Pressure × Area

Area (A) = (π/4) D2

= (π/4) × 2502

Area (A) = 49.09×103mm2

Load (w) = 0.13× 49.09 ×103

W = 6381.36 N = 638 Kg

Primary input data’s

Diameter of relief valve (D) = 250mm

Maximum pressure (P) = 1.3bar = 0.13N/mm2

Pin length (Lp) = 600mm

Assuming pin diameter (dp) = 60mm

From the above diagram

From the above diagram is represented by the length of pin = 600mm, then taking

momentum about the center point of the pin

Momentum (M) = 550Sin45×6381.36

= 2.48 × 106 Nmm

From the above diagram is represented by the length of the lever = 1300mm, then taking

moment about the point at P

P×1300 = 2.48×106

P = (2.48×106)/1300

=1909.05

P =190Kg

Finally the counter weight was calculated using above steps as P = 190kg

MODELING & ASSEMBLY

– Bottom reducer

– Seat

– Rubber gasket

– Bottom MS ring

– Top MS ring

– Cover

– Arm

– Arm pin

– Pin

– Lever

– Plummer Block

– Counter weight shaft

– Counter weight

MODELING

Modeling of Dead weight pressure relief valve components was developed by

using modeling software’s Pro-E.

The components are:

BOTTOM REDUCER

SEAT

RUBBER GASKET

BOTTOM MS RING

TOP MS RING

COVER

ARM

ARM PIN

PIN

LEVER

PLUMMER BLOCK

COUNTER WEIGHT SHAFT

COUNTER WEIGHT

ASSEMBLY

Components of dead weight valve was modeled and assembled by

using PRO-E software with proper dimension.

Assembled dead weight valve was developed and indicated with different

views.

Exploded view of dead weight pressure relief valve

3D view of dead weight pressure relief valve

Front view of dead weight pressure relief valve

Top view of dead weight pressure relief valve

Side view of dead weight pressure relief valve

ANALYSIS OF DEAD WEIGHT PRESSURE RELIEF VALVE

A suitable Finite Element was identified and selected.

Then finite element model of Dead Weight Pressure Relief Valve developed with

proper procedure in Ansys.

Finite Element Model of

Dead Weight Pressure Relief Valve

RESULT DISCUSSION

Dead weight Pressure relief valve with diameter 250mm was modified for changing

rupture disc.

The design of Dead weight pressure relief valve will be verified by some design

steps.

The shear stress and bending stress of lever was calculated.

The resultant value was verified with theoretical standard values of respective

material. The material was selected as Mild Steel.

Represents the contour plot of total distribution of von mises stress

S.NO

MECHANICAL

PROPERTIES

OF MILD STEEL

(Theoretical values)

DESIGNED VALUES OF PIN AND

LEVER(Dead weight pr.relief valve)

(as per calculation)RESULT

FOR PIN FOR LEVER

1Shear Stress

= 60Mpa

 

0.79Mpa

 

2.11MpaSAFE

2Bending Stress

= 80Mpa26.36Mpa

 

76.44MpaSAFE

CONCLUSION

Rupture disc in the Gas cleaning plant is affected by blast furnace top pressure

and also by gas reaction during cleaning process.

Once open, they cannot reseal and must be replaced.

Cost of rupture disc high because of shifting every time.

Replacement of rupture disc by Dead weight pressure relief valve will solve

the disc failure problem & replacement time.

When the pressure is high the valve is opened automatically and valve closed

with the aid of self weight, when the pressure is below the set value. So dead

weight pressure relief was selected .

BIBLIOGRAPHY

[1] R.S.KHURMI & J.K.GUPTA, Machine Design (First Multicolor Edition).

 

[2] R.K.BANSAL, Strength Of Materials (Fourth Edition)

 

[3] Southern African Pyrometallurgy 2011, Edited by R.T. Jones & P. den Hoed, Southern African Institute of Mining and Metallurgy, Johannesburg, 6–9 March 2011

[4] HARDARSHAN S. VALIA, Scientist, Ispat Inland Inc, Coke Production for Blast Furnace Iron making.

 

THANK THANK YOUYOU