Evaporation flow diagram (2 housings)

Contents

Contents

Leaf

Task

Introduction

1 Description of evaporator flow diagram

2 Evaporator design

3 Process calculation of evaporator

3.1 Purpose of calculation

3.2 Initial data

3.3 Material Balance

3.4 Boiling points of solutions

3.5 Useful temperature difference

3.6 Definition of heat loads

3.7 Selection of structural material

3.8 Calculation of heat transfer coefficients

3.9 Distribution of useful temperature difference

3.10 Refined Heat Transfer Surface Calculation

3.11 Determination of thermal insulation thickness

4 Calculation of barometric capacitor

4.1 Cooling water flow

4.2 Capacitor diameter

4.3 Barometric pipe height

4.4 Vacuum Capacity Calculation - Pump

5 Strength calculation of evaporator main elements

5.1 Purpose of calculation

5.2 Initial data

5.3 Separator shell

5.4 Separator Bottom

5.5 Heating chamber shell

5.6 Tubesheet

Conclusion

List of literature used

Introduction

Evaporation is the concentration of solutions of substantially non-volatile or few volatile substances in liquid volatile solvents.

Solutions of solid substances (aqueous solutions of alkalis, salts, etc.), as well as high-boiling liquids with very low vapour pressure at the evaporation temperature - some mineral and organic acids, polyhydric alcohols, etc. are subjected to evaporation.

Evaporation typically removes the solvent partially from the entire solution at its boiling point. Therefore, evaporation is fundamentally different from evaporation, which is known to occur from the surface of the solution at any temperatures below the boiling point. In some cases, the evaporated solution is subjected to subsequent crystallization in evaporators specially adapted for this purpose.

Production of highly concentrated solutions, practically dry and crystalline products makes their transportation and storage easier and cheaper.

Heat for evaporation can be supplied by any heat transfer agents used in heating. However, in the vast majority of cases, water vapour, which is called heating or primary, is used as the heating agent during evaporation.

The primary steam is either steam obtained from the steam generator or spent steam, or steam from the intermediate extraction of steam turbines.

The steam generated by evaporation of the boiling solution is called secondary.

The heat required to evaporate the solution is usually supplied through the wall separating the heat carrier from the solution. In some industries, concentration of solutions is carried out with direct contact of the evaporated solution with flue gases or other gaseous heat carriers.

Evaporation is carried out in single evaporators (single-hull evaporators). However, the most common are multi-body evaporators, consisting of several evaporators, or housings in which the secondary steam of each previous housing is sent as heating to the subsequent housing. At the same time, the pressure in the bodies connected in series (in the course of the evaporated solution) is reduced so as to provide a temperature difference between the secondary steam from the previous body and the solution boiling in this body, that is, to create the necessary driving force of the evaporation process. In these installations, only the first housing is heated with primary steam. Consequently, in multi-hull evaporators, significant primary steam savings are achieved compared to single-hull evaporators of the same capacity.

In the chemical and related industries, liquid mixtures, the concentration of which is carried out by evaporation, are characterized by a wide variety of both physical parameters (viscosity, density, boiling point, critical heat flux, etc.) and other characteristics (crystallizing, foaming, non-thermo-resistant solutions, etc.). The properties of the mixtures determine the basic requirements to the process conditions (vacuum - evaporation, direct - and counter-current, one - and multi-body evaporators), as well as to the design of evaporators.

This variety of requirements eliminates certain difficulties when choosing the right evaporator scheme, type of apparatus, number of stages in a multi-body evaporator. In general, such a selection is an optimal search task and is performed by technologically and economically comparing various variants using computers.

Conclusion

In this course work, a double-hull evaporator was calculated, consisting of forced circulation evaporators and a heating chamber for evaporating the sugar syrup solution.

The design of the evaporator meets a number of general requirements. These include:

High efficiency and heat transfer intensity at min volume of the apparatus and metal consumption for its manufacture;

- Simplicity of the device;

- Reliability in operation;

- Easy cleaning of the heat exchange surface;

- Easy inspection, repair and replacement of individual parts.

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