FIELD OF INVENTION

The presently claimed invention relates to a heat exchange device and a method of exchanging heat.

BACKGROUND OF INVENTION

Heat transfer is an important part of many processes in varied industries. In general, heat transfer involves at least one stream which is at high temperature and at least one other stream which is at low temperature, brought in contact with each other either in a direct manner or in an indirect manner to heat or cool, through heat transfer.

Heat exchangers are equipment typically used for indirect heat exchange between, at least two streams. The choice of a particular type of heat exchanger is dependent on the temperature difference between the two streams, the chemical nature of the streams, and the available installation space. Nevertheless, the most widely used heat exchangers are generally described as double pipe heat exchangers, shell and tube heat exchangers, and/or plate heat exchangers. Of these, shell and tube heat exchangers find wide application in almost all industries. A shell and tube heat exchanger majorly comprises a shell which contains a plurality of tubes disposed on the interior of the shell and wherein at least one of the streams flows around the tubes, while the plurality of tubes is bundled together in the form of tube bundles and wherein at least one of the other streams flows through the tubes. The streams, in the shell side as well as the tube side, may flow in a direction parallel, counter-current, or cross-flow to each other.

JP 11013551 discloses an EGR (exhaust gas recirculation) cooler for cooling the exhaust gas using a coolant of an engine. TheFIG. 10discloses the EGR cooler. The chamber21in the EGR cooler is having an inlet25and an out let26for the continuous flow of a coolant in order to suppress the boiling of the inlet fluid. Therefore, a continuous heat exchange process is involved between the continuous flow of coolant in chamber21and the inlet fluid. JP 11013551 further discloses that the chamber21can be used for introducing a higher boiling liquid such as lubricating oil, or light oil etc having a higher boiling point in order to increase the efficiency of the cooling.

US 2013/112381 A1 describes a heat exchange device comprising plurality of tubes arranged parallel to one another to form one or more tube bundles inserted axially in a cylindrical shell. A first fluid supplied through one or more first inlet holes at a first end of the cylindrical shell and oriented axially, flows inside the tubes and a second fluid, supplied through a second inlet hole, flows inside the cylindrical shell to effect heat transfer with the first fluid through the tube walls.

One end of the tubes is connected to a tube plate at first inlet hole(s), which separates the second fluid from the first fluid. At least two impingement plates, each provided with plural through holes, are placed in succession between each first inlet hole and the tube plate. The impingement plates are parallel to one another and orthogonal to the cylindrical shell central axis to distribute the first fluid inside the tubes.

GB 2 126 116 A describes an evaporator including a plurality of vertical heat transfer tubes, a liquid inlet plenum enclosing the lower ends of the tubes, a distributor plate located within the inlet plenum and having a multiplicity of orifices therethrough, said distributor plate being spaced apart from the inlet ends of the tubes to define a manifold, which interconnects said inlets to allow cross flow.

EP 1 586 370 A2 describes a reactor arrangement for carrying out catalytic gas phase reactions, comprising a jacket tube reactor (2), a bundle of tubes and a separate, after cooler (3) directly connected to the side outlet, where the cross sectional area in the after cooler is essentially congruent with the cross sectional area in the jacket and both the cross sectional areas are oppositely paired in large numbers.

While almost all kinds of streams, irrespective of their temperature, can be cooled or heated in the shell and tube heat exchanger, there are some conditions where these heat exchangers do not result in an efficient heat exchange between the streams. One such condition arises when the stream on one side of the exchanger, say in the tube side, is near its boiling point. In such conditions, the stream on the other side of the exchanger, here the shell side stream, can excessively heat the tube side stream to its boiling point, thereby causing violent disruptive boiling of the tube side stream. This causes a non-uniform distribution of the tube side stream inside the tube, thus, resulting in an inefficient heat exchange between the shell side and the tube side streams. Additionally, this also results in loss of the tube side stream due to vapor formation, thereby increasing the operational cost of the exchanger.

Thus, it is an objective of the presently claimed invention to provide a heat exchanger which does not result in violent disruptive boiling of the tube side stream, thereby resulting in the uniform distribution of the tube side stream with minimal or no loss.

SUMMARY OF THE INVENTION

Surprisingly, it has been found that the above defined object is achieved by inserting an insulation tube sheet between the distributor assembly and the shell side outlet of a heat exchanger. The insertion of the insulation tube sheet creates an inlet insulation space between the distributor assembly and insulation tube sheet. The creation of the inlet insulation space not only resolves the problems associated with the overheating of the tube side stream at the distribution assembly, but also reduces the amount of the shell side stream required for heat exchange between the tube side stream and the shell side stream, thereby resulting in additional cost saving and rendering the heat exchange process economic.

Accordingly, in one aspect, the presently claimed invention is directed to a heat exchanger (100) comprising:

a shell (101);

a tube side inlet (106) and a tube side outlet (107);

a shell side inlet (105) and a shell side outlet (104);

a plurality of tubes (102);

a distribution assembly (108);

an inlet tube sheet (114) and an outlet tube sheet (112); and

an insulation tube sheet (103);

wherein,

the insulation tube sheet (103) is arranged between the distributor assembly (108) and the shell side outlet (104) to create an insulation space (109) there between; and

the tubes (102) are fitted inside the shell (101) between the distributor assembly (108) and the outlet tube sheet (112) and are in communication with the tube side inlet (106) through the distributor assembly (108) and the tube side outlet (107).

In another aspect, the presently claimed invention is directed to a method of exchanging heat using the above heat exchanger, comprising the steps of:i. feeding a tube side stream through said tube side inlet (106) to said distributing assembly (108),ii. passing the tube side stream through said plurality of tubes (102),iii. feeding a shell side stream through said shell side inlet (105) andiv. exchanging the heat between the tube side stream in the plurality of tubes (102) with the shell side stream,

wherein the temperature of at least one of the liquid components of the tube side stream entering through the tube side inlet (106) to the distributing assembly (108) is near its boiling point; and the temperature of the shell side stream entering through the shell side inlet (105) is higher than at least one of the liquid components of the tube side stream at distributing assembly (108).

In another aspect, the presently claimed invention is directed to a method of concentrating a liquid using a falling film heat exchanger as described herein comprising the steps of:i. feeding a tube side stream through said tube side inlet (106) to said distributing assembly (108),ii. passing the tube side stream through said plurality of tubes (102) having an inner wall and forming a film of the tube side stream along the inner wall,iii. feeding a shell side stream through said shell side inlet (105),iv. exchanging the heat between the tube side stream in the plurality of tubes (102) with the shell side stream, andv. obtaining a concentrated stream through said tube side outlet (107) of the shell; wherein, the temperature of the tube side stream entering through the tube side inlet (106) to the distributing assembly (108) is near its boiling point; and

the temperature of the shell side stream entering through the shell side inlet (105) is higher than the tube side stream at the distributing assembly (108).

