Ascending film evaporators

Contents

Contents:

Introduction

1. Status of the question

2. Technical descriptions and calculations

2.1.Process diagram operation principle description

2.2.Material calculation of the unit

2.3. Thermal calculation of the unit

2.4.Structural calculation of the apparatus

2.5.Compute Component Equipment

2.6.Hydraulic calculation of the product line and

selection of injection equipment

Conclusion

List of sources used

Introduction

Evaporation - the process of concentration during boiling of solutions of solid non-volatile substances - is carried out at one- and multi-shell evaporation stations. Single-body evaporation is used in small-scale industries where the simplicity of the device is important. The heat consumption in such plants is high, since about 1 kg of steam is consumed for the evaporation of 1 kg of water. By the nature of the work, single-hull evaporation stations are periodic and continuous.

Single-hull stations of periodic action most often operate on the principle of "with a falling solution level." This saves evaporation time, but the evaporator is used as a preheater and evaporator, which is impractical since the cost per surface of the evaporator is many times greater than the preheater. In a continuous apparatus (as opposed to batch), evaporation of the solution proceeds at a constant process mode, which allows you to automate the process and improve the quality of the product.

The concentration of solution in the apparatus during continuous evaporation is closer to the final one, so the heat transfer coefficient is lower than the average heat transfer coefficient during the periodic process. This is a disadvantage of continuous evaporation, which results in the time required to remove the same amount of water at an equal heating surface in the continuous apparatus being longer than in the periodic apparatus.

Repeated evaporation is a process in which secondary vapors are used as heating steam and, therefore, significant heat savings are achieved. The essence of multiple evaporation is that the process is carried out in several series-connected apparatuses in which the pressure is maintained such that the secondary steam of the previous apparatus can be used as heating steam in a subsequent apparatus in which, due to the reduced pressure, the solution boils at a lower temperature. When the two machines work together, the fresh steam introduced into the heating chamber of the first evaporator allows to evaporate approximately double the amount of water, that is, the steam flow per unit of evaporated water is reduced by half, compared to evaporation in one apparatus.

Conclusion

In the process of calculating the evaporator for concentrating meat-bone broth, we calculated a evaporator with an ascending film.

A shell-tube heater and a barometric condenser were calculated, a pump for pumping and a vacuum pump were selected.

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