Design of rectification plant

Contents

Introduction

1 Analytical Overview

1.1 Periodic rectification of binary mixtures

1.2 Continuous rectifiers

for separation of binary mixtures

2 Design part

2.1 Material Balance

2.2 Hydraulic calculation

2.2.1 Determination of steam velocity and column diameter

2.2.2 Determination of column diameter

2.2.3 Calculation of light liquid layer height

2.2.4 Calculation of gas-liquid (bubble) liquid layer height

2.2.5 Calculation of relative free section of tray

2.2.5 Calculation of splashdown

2.2.6 Calculation of tray hydraulic resistance

2.2.7 Check of overflow device operation

2.3 Column height calculation

2.3.1 Determination of mass output coefficients

2.3.2 Determination of kinetic parameters

2.3.3 Determination of the number of trays

2.3.3 Height calculation

2.3.4 Calculation of hydraulic resistance of the column

2.4 Thermal calculation of the plant

2.4.1 Heat Balance

2.4.2 Approximate calculation of heat exchangers

2.4.3 Detailed reflux calculation

Conclusions

List of literature

Application

Course Design Assignment

Variant No. 13

Design a distillation plant to separate ethanol-chlorobenzene at atmospheric pressure.

Make detailed calculation of rectification column and reflux condenser. Cubic evaporator, source mixture heater, distillate cooler and bottom residue, calculated approximately.

Select standard sets. Make a general dephlegmator drawing and a sketch of the process diagram of the unit.

Initial data for calculation

Column with sieve trays.

The capacity of the unit according to the initial mixture is 4.28 kg/s.

The concentration of the volatile component in the starting mixture was 0.517 mol.

The concentration of the volatile component in the distillate was 0.873 mol.

The concentration of the volatile component in the bottoms was 0.0524mol.

The temperature of the feed mixture is 22 ° C.

Cooling water temperature 14 ° С.

List of issues to be developed

1 Analytical Overview

Review and substantiation of rectification plant design selection.

2 Main part

2.1 Description of the process diagram of the rectification plant.

2.2 Detailed calculation and selection according to catalogs of rectification column and dephlegmator (heat carrier flow mode). Evaporator, bottom residue cooler, distillate cooler and initial mixture heater shall be calculated approximately.

Graphic Material List

1 Process diagram of rectification plant

2 Dephlegmator general view drawing

Hardware and Software Requirements

Hardware requirements are not required.

Software: Microsoft Windows operating system, Microsoft Windows Word word processor, Mathcad 14, COMPASS 3D graphics program.

Introduction

In this course work, the rectification process is considered, which is carried out continuously at atmospheric pressure. Rectification is a process of multiple partial liquid evaporation and vapor condensation. The process is carried out by contacting streams of steam and liquid having different boiling points and is carried out usually in column apparatuses. At each contact, a substantially low boiling component evaporates from the liquid, and a high boiling component passing into the liquid condenses from the vapors.

This two-way interchange of components is repeated many times, allowing the final pairs of almost pure NC to be radiated. These vapors, after condensation in a separate apparatus, give distillate and reflux returned to reflux the column and react with the rising vapors. Vapors are obtained by partial evaporation from below a column of residue that is almost pure HC.

Rectification has been known since the beginning of the 19th century as one of the most important technological processes mainly in the alcohol and oil industries. Currently, it is increasingly used in a wide variety of chemical technologies, where the release of components in pure form is very important (the production of polymers, semiconductors and various other high purity substances).

Analytical Overview

Rectification processes are carried out periodically or continuously at various pressures: atmospheric, under vacuum (to separate mixtures of high-boiling substances), as well as under pressure higher than atmospheric (to separate mixtures that are gaseous at normal temperatures).

Conclusion

During the operation, columns and 5 heat exchangers were calculated.

Their characteristics:

Rectification Column

Diameter for top column -1.2m

Height-8m

Number of trays-11

Distance between trays-0.5m

Total column resistance 1922 Pa

Evaporator Cube

-cucumber;

-shell diameter D 800mm

- pipe diameter 20 × 2mm;

- number of pipes 717;

- heat exchange area 180;

- length of pipes is 4 m.

Bottoms cooler

-cucumber;

-shell diameter Dnar 325mm

- pipe diameter 20 × 2mm;

-number of pipes 100;

- heat exchange area 25;

- pipe length is 4 m.

Feed preheater

-cucumber;

-shell diameter D 800mm

- pipe diameter 25 × 2mm;

-number of pipes 257;

- heat exchange area 40;

- pipe length 2m.

Dephlegmator

-cucumber;

- double-thread

-shell diameter Dnar 600mm

- pipe diameter 25 × 2mm;

-number of pipes 240;

- heat exchange area 38;

- pipe length 2 m.

Distillate Cooler

.

-cucumber;

-shell diameter Dnar 325mm

- pipe diameter 20 × 2mm;

-number of pipes 100;

- heat exchange area 19.5;

- pipe length 3 m.