Design of Heat Exchanger in HCL in production heat transfer operation conduction convection shell and tube heat exchanger

1. BANSILAL RAMNATH AGARWAL CHARITABLE TRUST’S
VISHWAKARMA INSTITUTE OF TECHNOLOGY
PUNE- 411037
(An Autonomous institute Affiliated to University of Pune)
Project Report
On
Design Of Heat Exchanger for Manufacturing
of Hydrochloric Acid
Under The Guidance of
Prof. Dr. Hemlata Uday Karne
Presented By: CH-B2- Group 9
12020121 30 Patil Rushikesh
11910969 33 Parth Patle
12020195 36 Puri Ashutosh
12020172 42 Rankhamb Shubham
12020015 48 Sanap Rajkumar

2. Contents
1. Introduction
2. Literature Survey
3. Manufacturing process
4. Design
5. Conclusion
6. References

3. Introduction
Hydrogen chloride (HCl), a compound of the elements hydrogen and chlorine,
a gas at room temperature and pressure. A solution of the gas in water is
called hydrochloric acid. Hydrogen chloride may be formed by the direct
combination of chlorine (Cl2) gas and hydrogen (H2) gas; the reaction is rapid at
temperatures above 250 °C (482 °F). The reaction, represented by the equation
H2 + Cl2 → 2HCl, is accompanied by evolution of heat and appears to be
accelerated by moisture. Hydrogen chloride is commonly prepared both on a
laboratory and on an industrial scale by the reaction of a chloride, generally that
of sodium (NaCl), with sulfuric acid (H2SO4). It is also produced bythe reaction
of some chlorides (e.g., phosphorus trichloride, PCl3, or thionyl chloride, SOCl2)
with water and as a by-product of the chlorination of many organic substances
(e.g., methane or benzene).
Hydrochloric acid is prepared by dissolving gaseous hydrogen chloride in water.
Because ofthe corrosivenature of the acid, ceramic, glass, orsometimes tantalum
apparatus is commonly used. Hydrochloric acid is usually marketed as a solution
containing 28–35 percent by weight hydrogen chloride, commonly known as
concentrated hydrochloric acid. Anhydrous liquid hydrogen chloride is available,
but because heavy and expensive containers are required to store it, the use of
hydrogen chloride in this form is limited.
Hydrochloric acid is present in the digestive juices of the human stomach.
Excessive secretion of the acid causes gastric ulcers, while a marked deficiency
of it impairs the digestive process and is sometimes the primary cause of
deficiency anemias. Exposure to 0.1 percent by volume hydrogen chloride gas in
the atmosphere may cause death in a few minutes. Concentrated hydrochloric
acid causes burns and inflammation of the skin.
Hydrochloric acid (HCl) is a versatile chemical that has a number of different
industrial uses. Some examples are hydrometallurgical processing (e.g.,

4. production of alumina and/or titanium dioxide), chlorine dioxide synthesis,
hydrogen production, activation of petroleum wells, and miscellaneous
cleaning/etching operations including metal cleaning (e.g., steel pickling). Also
known as muriatic acid, HCl is used by masons to clean finished brick work.
Hydrochloric acid is also a common ingredient in many reactions and is the
preferred acid for catalyzing organic processes. One example is a carbohydrate
reaction promoted by hydrochloric acid, analogous to thosein the digestive tracts
of mammals. Hydrochloric acid may be manufactured by several different
processes; however, over 90 % of the HCl produced in the U.S. is a by-product
of the chlorination reaction. Some examples of chlorination reactions are the
production of dichloromethane, trichloroethylene, perchloroethylene, and vinyl
chloride.
Chlorine and hydrochloric acid works are taken together becausechlorine is often
generated as an intermediate in the manufacture of hydrochloric acid. The classis
mercury cell electrolysis produces bothchlorine and hydrogen and these are then
mixed and burnt to form hydrochloric acid gas, hydrochloric acid gas can also be
formed from the use of chlorides in chemical processes, especially when a
chloride and an acid react together. In all cases, the hydrochloric acid gas is
absorbed in water to form liquid hydrochloric with an acid strength of 33-35
percent. Air pollution problems can also arise when chlorine orhydrochloric acid
are used in other processes. Chlorine works are defined as works in which
chlorine is made or used in any manufacturing processes. Hydrochloric acid
works are defined as works where hydrogen chloride gas is evolved either during
the preparation of liquid hydrochloric orfor use in any manufacturing process,or
as the result of the use of chlorides in a chemical process.

5. Literature Survey
Transfer of heat from one fluid to another is an important operation for most of
chemical industry. To achieve a particular engineering objective, it is very
important to apply certain principles so that the product development is done
economically. This economic is important for the design and selection of good
heat transfer equipment. Such equipment’s for efficient transfer ofheat are called
as heat exchangers. Thus heat exchangers facilitate the exchange ofheat between
the fluids that are different temperature while keeping them from mixing with
each other. Heat exchangers find widespread use in power generation, chemical
processing, electronics cooling, air-conditioning, refrigeration, and automotive
applications. These heat exchangers had become the essential requirement of the
current society as they do not cause any harmful effects to the environments. The
costinvolved in this energy extraction is also very less and economical. There are
different types ofheat exchangers with different designs, materials and have been
customized to meet specific needs. Out of this Shell and Tube heat exchanger
without doubt, one of the most widely used heat exchanger. Shell and tube heat
exchangers are commonly used in the chemical and process industries. These
devices are available in a wide range of configurations as defined by the Tubular
Exchanger Manufacturers Association (TEMA). The applications of single-phase
shell-and-tube heat exchangers are quite large because these are widely in
chemical, petroleum, power generation and process industries. In essence, a shell
and tube exchanger is a pressure vessel with many tubes inside of it. One process
fluids flows through the tubes of the exchanger while the other flows outside of
the tubes within the shell.
I. Classification:-
This TEMA-type designation comprises three capital letters. The letter describes
the stationary head type at the front end of the apparatus, according to the first
column of Fig 1: five different alternatives are possible. The second letter

6. describes the heat exchanger shell, selected from the seven types shown in the
middle column of Fig. 1. Finally, the third letter, chosen from the eight
alternatives shown in the third column of Fig. 1, describes the stationary or
floating head type at the rear end. For example, an AES TEMA-type S&THX is
an exchanger with a channel and removable cover front head, a one-pass shell,
and a floating head with backing device rear end. The three most common types
of shell-and tube exchangers are Fixed tube-sheet design (L, M, and N type rear
header) This is a very popular version as the heads can be removed to clean the
inside tubes.
Fig. 1 Shell & Tube Heat Exchanger
The front head piping must be unbolted to allow the removal of front head, if this
is undesired this can be avoided by applying a type a front head. It is not possible
to clean the outside surface of the tubes as these are inside the fixed part.
Chemical cleaning can be used. B. U-tube design (front header and M type rear
header) It permits unlimited thermal expansion the tube bundle can be removed
for cleaning and small bundle to shell clearance can be achieved C. Floating-head
type (P, S, T, W type rear headers). A floating head is excellent for applications
where the difference in temperature between the hot and cold fluid causes
unacceptable stresses in the axial direction of the shell and tubes. The floating
head can move.

7. Manufacturing Process:
Hydrochloric acid is manufactured by following methods:
1) From various chlorination reaction: C6H6 +Cl2 → H6H5Cl + HCl
2) From salt and sulphuric acid: 2 NaCl + H2SO4 → 2 HCl + Na2SO4
3) From Synthesis process: H2 + Cl2 → 2 HCl
From Salt and Sulphuric Acid:
Fig. 1 Manufacturing of HCl from Salt & Sulphuric Acid
ProcessDescription:
Reactions: NaCl + H2SO4 → NaHSO4 + HCl
NaHSO4 + NaCl → Na2SO4 + HCl
 Both reactions involve the displacement of volatile acid from salt. The
equilibrium can be displaced in desired direction by choice of condition i.e.
promoting volatilization of HCI.

8.  The high temperature process is superior to vacuum for this purpose. To
promote reaction rate, it is desirable to have temperature sufficiently high to
keep at least one of the reacting component in liquid condition.
 There is no difficulty in first stage ofdecompositionbut second stage required
temperature of about 400°C to liquefy NaHSO4. The higher limit to
temperature is the attack of corrosiverelative mass on furnace. The sludge i.e.
Na₂ SO4 is collected from bottom of the furnace.
 The product and unconverted H₂ SO4 is send to further processing in which
there is recovery of H₂ SO4 by cooling tower and HCI is recovered as main
product from absorber.
Synthesis Process:
 The process generates hydrogen chloride byburning chlorine in a few per cent
excess ofhydrogen, chlorine and hydrogen are obtained as by-products during
the manufacture of caustic soda (electrolysis of NaCl solution).

9. Process Description:
 Dry hydrogen is made to bum in acid-resisting burner fitted in a combustion
chamber lined with silica bricks. Dry chlorine is passed into the combustion
chamber when hydrogen burns in an atmosphere of chlorine to give to give
HCl.
 The gas is passed through a Cooler cooled by water spray and then through
Absorber through which water flows down in controlled quantities.
 The absorber is also cooled by a spray of cold water to remove the heat of
absorption of HCI in water. The solution of HCI flows into Storage tank
below.
 An exhaust fan on the extreme right pumps out the waste gases which escape
in the atmosphere.

10. Design :-
 Calculation
Shell Side
Temperature Tube Side Temperature
Temperature Unit Temperature Unit
T1 280 °C t1 25 °C
T2 195 °C t2 75 °C
Mass flow rate of sulphuric acid + Salt = 100000 kg/hr 27.77777778 kg/sec
Mass flow rate of steam = 37665.34 kg/hr 10.46259553 kg/sec
T1= T1 - t2 205 °C
 t1 170 °C
Pressure Unit Pressure Unit
P2 4.3 Bar P1 2.3 Bar

11. Assume
Outer diameter = 20 mm 0.02 m
Inner diameter= 16 mm 0.016 m
Length
= 4.88 m
Radius= 0.01 m
Cp for sulphuric acid = 1.34 KJ/Kg.°C
Cp for H20 = 4.2 KJ/Kg.°C
Q = M* CP * 
Q= 3163.889 W
Coolong Water flow = Q/Cp * 
37665.34 Kg/Hr
Tlm= ()/LN(T1/T2)
Tlm= 186.9543 °C
Q = U*A*Tlm*Ft
A= Q /( U*(Tlm*Ft))
A = 914.1403588 m2
Assuming,
U = 550
W/K
m^2
Ft = 0.85
R = 1.7
S = 0.588235294

12. Tubes
Outer diameter = 20mm 0.02 m
Inner diameter=16mm 0.016 m
Tube length = 4.88 m
Actual Available Length
= 4.83 m
0.05 m would be in the tube
sheet
No. of tubes = 3013.742 3014
Tringular pitch
Pt= 1.25 pitch
Tube bundal
dia Db = Dod (NT/K1)^(1/n1)
Db = 1.415883 m 1415 mm
Shell
Additional Clearance = 68 mm
Total Dia. of Shell = 1483 mm
K1 = 0.249
n1 = 2.207

13. Simulation in DWSIM
Heat exchanger1-
Fig. 3 Feed Inlet (First Heat Exchanger)
Fig. 4 Hot Water Inlet

14. Fig. 5 Hot Water Outlet
Fig. 6 Feed Outlet

15. Fig. 7 Heat Exchanger Specification

16. Fig. 8 First Heat Exchanger
Table No. 1

17. Fig. 9 Second Heat Exchanger
Table No. 2

18. Fig. 10 Third Heat Exchanger
Table No. 3

19. Conclusion
In the manufacturing process, heat exchangers are used to recover heat from two
process fluids. Shell-and tube heat exchangers are the most commonly used heat
exchangers in process industries due to their comparatively quick productionand
adaptability to diverse operating conditions. Nowadays, however, a variety of
companies are looking for more competitive and less time Consuming
alternatives for building heat exchangers for shells and tubing. According to
literature and industrial studies, there is a need for successfuldesign solutions for
manufacturing HCL. The construction of exchanger requires a vast number of
geometric and operational variables as part of the quest for an exchanger
geometry that satisfies the necessity for heat duty and a series of design
constraints. Typically the reference geometric configuration of the equipment is
selected first and the permissible pressure drop value is set. The values of the
design variables are then specified on the basis of the design requirements and
the assumption of certain mechanical and thermodynamic parameters in order to
provide a satisfactory coefficient of heat transfer leading to an acceptable use of
the heat exchanger surface.
The construction of heat exchanger, i.e. thermal and mechanical design, was
carried out by means of DWSIM specifications, both manually and using
software. It is noticed that the construction of exchanger accomplished by both
methods is very straightforward, basic advancement and time-consuming as a
modern heat exchanger.

20. References
1. Dryden's Outlines Of Chemical Technology by Rao
2. Nptel, “Lecture 1: Heat Exchangers Classifications,” Chem. Eng. Des. - II,
2006.
3. I. Horvath, “HEAT EXCHANGER DESIGN.,” Glas. Int., 1983, doi:
10.13182/nse66-a12015184.
4. K. Thulukkanam, Heat Exchanger Design Handbook. 2013.