What is the difference between a heat exchanger and a reboiler

What are the two types of heat exchangers? There are two main types of regenerative heat exchangers —static heat exchangers and dynamic heat exchangers. Dacio Sagarribay Teacher. What is a reflux drum? Reflux drum. Reflux is that portion of a tower's condensed overhead liquid product that is cycled back to the top of the tower where it flows downward to provide cooling and condensation of the upflowing vapors.

Phebe Nosihin Supporter. How does a distillation column work? The distillation column is made up of a series of stacked plates. A liquid feed containing the mixture of two or more liquids enters the column at one or more points. The liquid flows over the plates, and vapor bubbles up through the liquid via holes in the plates. In essence, the hot mixture is pumped into the bottom. Saqib Bicheiro Supporter. What is double pipe heat exchanger?

In its simplest form, the double pipe heat exchanger , also known as a concentric pipe , hairpin, jacked pipe and jacketed U-tube heat exchangers , consists of a single tube mounted inside another.

One fluid flows in the inner pipe , while a second fluid flows in the outer pipe annuals. Janice Aretxaga Beginner. What is floating head heat exchanger? They are recommended in place of fixed plate heat exchanger for high pressure and temperature operation.

Ehab Prantl Beginner. Where are shell and tube heat exchangers used? A more complex type of reboiler is the thermosyphon, which comes in two primary types: vertical and horizontal. The type of thermosyphon that is used will depend on the orientation of the heating fluid tubes and the flow of the liquid.

Aside from that, operative principles are the same as with kettle reboilers. Thermosyphons operate by passing liquid from the bottom of the tower to the reboiler by gravity, which is then passed through the inside of the heated tubes in order to create a two-phase liquid-vapor product. The liquid-vapor product is transferred through a pipe back into the tower, where separation occurs before the non vaporized liquid is passed back into the reboiler.

Thermosyphons are also able to provide their own liquid head, meaning that the use of pumps is usually not necessary. Pump around reboilers are forced circulation heat exchangers that create two phase flow on the outlet that goes back to the column and creates the necessary vapor traffic in the column. From where you got the information that LMTD is not applicable in case of kettle reboilers?

Just the boiling curve and you will come to know delta T is essential for boiling and is a governing factor in reboiler designs. Kettle reboiler - K type shell shell side boiling with very high re-circulation of shell side fluid.

In case of boiling, the dominant coefficient is boiling hence less effect of circulation rate and boiling coefficient is function of wall super heat delta T or MTD , boiling liquid critical pressure and surface tension etc. Keep in mind that vapor fraction in case of kettle is 1 at exit nozzle however it's always less than 1 at exit of tube bundle, any entrainment of liquid drops is taken care by vapor space provided above bundle.

If the boiling is for a single component at constant temperature, the standard LMTD can be used. For a mixture boiling over a temperature range,it gets complicated. To be safe, use the outlet temperature of the boiling mixture in order to calculate the LMTD. Community Forum Software by IP.

Sign In Create Account. Featured Articles Check out the latest featured articles. File Library Check out the latest downloads available in the File Library. New Article Product Viscosity vs. Featured File Vertical Tank Selection. A whole variety of forms of reboiler have been used in practice, some of which are described briefly below. General reviews of the forms and design of reboilers are given by McKee , by Ploughman and by Whalley and Hewitt The simplest approach is to mount the reboiler in the distillation tower itself as is illustrated in Figure 1.

Here, boiling takes place in the pool of liquid at the bottom of the tower, the heating fluid being inside the bundle of tubes as shown. The major problem with internal reboilers is the limitation imposed by the size of the distillation column. This limits the size of the reboiler. Another problem sometimes encountered is that of mounting the bundle satisfactorily into the column.

The problem of size restriction can be overcome if compact heat exchangers are used. Thus, Plate-Fin Exchangers are used commonly as internal reboilers in the distillation towers of air separation plant.

Another form of compact heat exchanger which has been used for this type of duty is the printed circuit heat exchanger which has an even higher heat transfer surface area per unit volume.