WELCOME

HEAD OF DEPARTMENT. REVIEW PANNEL MEMBERS.

SUPERVISORS.

REDESIGN OF SHELL AND TUBE HEAT EXCHANGER

GUIDED BY : Prof. Mr. M.JOHN IRUTHAYA RAJ

Rinu cherian : 961411114074Sanju Jacob : 961411114078Sreenath P : 961411114086Vivek George Mammen : 961411114100

GROUP MEMBERS

ABSTRACT. AIM. DIAGRAM OF SHELL AND TUBE HEAT EXCHANGER. COMPONENTS OFSHELL ANDTUBE HEAT.

EXCHANGER. DESCRIPTION . DIMENSION OF SHELL ANDTUBE HEAT

EXCHANGER. COMPANY REQUIREMENTS. METHODS ADOPTED. EFFECTIVENESS OF EXISTING & NEW HEAT

EXCHANGER. PERCENTAGE CHANGE IN EFFECTIVENESS.

TABLE OF CONTENT:

Heat exchanger plays a prominent role in the field of engineering, especially in chemical and petrochemical field.

Heat exchanger exchanges the heat between to process streams.

The concept behind the heat exchanger is the use of pipes or vessel to heat or cool one liquid.

Shell and tube heat exchanger is used to establish heat transfer from hot fluid based on the requirement.

In this project we have enhanced the efficiency of the heat exchanger by increasing the number of tubes inside the shell surface i.e from (184-235).by increasing the number of tubes we have concluded that the effectiveness has been enhanced from 5.70 to 8.87.the overall effectiveness is 34.4%.

ABSTRACT

The aim of the project is to redesign a shell and tube heat exchanger to accommodate an enhanced thermal load of 65% in the process line.

AIM

DIAGRAM OF SHELL AND TUBE HEAT EXCHANGER:

It is essential for the designer to have a good working knowledge of the mechanical features of STHEs and how they influence thermal design. The principal components of a shell and tube heat exchanger are: Shell, shell cover. Tubes. Tube sheet. Baffles Nozzles.

COMPONENTS OF SHELL AND TUBE HEAT EXCHANGER

SHELL AND SHELL COVER: Shell is the container for the shell fluid and the tube bundle is placed inside the shell. Shell diameter should be selected in such a way to give a close fit of the tube bundle.Shells are usually fabricated from standard steel pipe with shell thickness of 3/8 inch for the shell ID of 12-24 inch can be satisfactorily used up to 300PSI of operating pressure. TUBE: Tube OD of ¾ and 1 are very common to design a compact heat exchanger. The most efficient condition for heat transfer is to have the maximum number of tubes in the shell to increase turbulence

DESCRIPTION:

The tube thickness is expressed in terms of BWG (Birmingham Wire Gauge) with tube length of 6, 8, 12, 16, 20 and 24 ft are preferably used.TUBE SHEET: The tubes are fixed with tube sheet

that form the barrier between the tube and shell fluids. The tubes can be fixed with the tube sheet using ferrule and a soft metal packing ring. The tubes are attached to tube sheet with two or more grooves in the tube sheet wall by “tube rolling”. BAFFLES: Baffles are used to increase the fluid velocity by diverting the flow across the tube bundle to obtain higher transfer co-efficient. The distance between adjacent baffles is called baffle-spacing.

DESCRIPTION CONTINUED:

The baffle spacing of 0.2 to 1 times of the inside shell diameter is commonly used. Baffles are held in positioned by means of baffle spacers. Also shows two other types of baffles. The single segmental baffles. Double segmental baffles. Triple segmental baffles.

DESCRIPTION CONTINUED:

Tube Length -4.94m Tube Diameter-0.0254m

Shell Diameter-0.485 Mass flow rate of TiCl4-3.47kg/s

Pipe lyout-60o triangular Baffle spacing-0.274m Shell thickness-0.01m Flow configuration-counter

Pipe layout angle-60o

Number -184 Tube pitch-0.013125

DIMENSION OF THE EXISTING HEAT EXCHANGER:

Must cool chemical from 150oc to40oc Heat exchanger height cannot exceed 6m Heat exchanger shell diameter should not

exceed Minimize heat exchanger weight and hence

cost No variation in pressure

 

COMPANY REQUIREMENTS:

We are planning to design, By keeping two shell and tube heat exchangers in

parallel. By increasing the number of tubes. By increasing the length of the heat exchanger.

METHODS ADOPTED TO ENHANCE THE THERMAL LOAD

Methods Adopted

By keeping two shell and tube heat

exchangers in parallel.

By increasing the number of tubes.

Simpler design.Can withstand

outdoor conditions.

The mass flow rate of TiCl4 is increased.

More heat transfer area than required quantity.

Easy installation.

BY KEEPING TWO SHELL AND TUBE HEAT EXCHANGERS IN PARALLEL:

On enhancing the capacity of the plant, the mass flow rate of TiCl4 is increased.

The new mass flow rate = 20625 kg/hr = 5.73 kg/sec. Considering the two heat exchangers of tubes in a parallel to

satisfy the requirements.

METHOD:1

1. More heat transfer area than required quantity.2. Easy installation.

ADVANTAGE:

BY INCREASING THE NUMBER OF TUBES:

On enhancing the capacity of plant, the mass flow rate of TiCl4 (pure 99.98%) increase by 65%.

Method : 2

Simpler design. Can be easily manufactured and purchased in local market. Can withstand outdoor conditions. Cleaning can be normally done. A spare heat exchanger can balance the production line while

cleaning or maintenance. Even though it satisfies interior design requirements that of plate heat

exchanger and twisted tube heat exchanger which are readily available.

Easiness in controlling the equipment.

ADVANTAGES:

€= (mhch/cmin)*(T1-T2)/ (T1-t1)

Where mh- mass flow rate of hot fluid.

Ch-specific heat of hot fluid.

Cmin-smaller value of mhch and mccc.

mh=3.47kg/sec

ch=146.2kJ/kg

cmin=87.906W/K

T1=150oc

T2=40oc

t1=40oc

Therefore effectiveness €=(3.47*146.2/87.906)*(150-40)/(150-40)€=5.77

EFFECTIVENESS OF EXISTING HEAT EXCHANGER:

€= (mhch/cmin)*(T1-T2)/ (T1-t1)

Where mh- mass flow rate of hot fluid.

Ch -specific heat of hot fluid.

Cmin-smaller value of mhch and mccc.

mh=5.73kg/sec

ch=146.2kJ/kg

cmin=87.906W/K

T1=150oc

T2=40oc

t1=40oc

Therefore effectiveness €= (5.73*146.2/87.906)*(150-40)/(150-40)€=8.80

EFFECTIVENESS OF NEW HEAT EXCHANGER:

Percentage change in effectiveness= ((€new exchanger-€old exchanger)/€ new exchanger ) Percentage change in effectiveness = ((8.80-5.77)/8.80)*100 Percentage change in effectiveness =34.4%

PERCENTAGE CHANGE IN EFFECTIVENESS:

So far the existing design of shell and tube has been studied comprehensively. A detailed study of modifying the existing one to increase the effectiveness of the plant by increasing the number of tubes from 184 to234.By increasing the number of tubes we have, identified a considerable improvement on the effectiveness of heat exchanger which has been found out to be 34.4%.

CONCLUSION

THANK YOU