Split type tubular falling film evaporator

Abstract

The invention relates to a split type tubular falling film evaporator. The split type tubular falling film evaporator comprises a tubular falling film heater, the upper end of the tubular falling filmheater is connected with an upper cover which is provided with a solution inlet, the lower end of the tubular falling film heater is connected with a liquid trap, the side wall of the liquid trap isconnected with a communicating pipe, one end of the communicating pipe is connected with a separator, both the inner diameter and the volume of the separator are greater than those of the liquid trap,and the separator is provided with a secondary steam outlet which is arranged above the connector between the communicating pipe and the separator. According to the split type tubular falling film evaporator, the lower end of the tubular falling film heater is connected with the liquid trap for collecting heated solution and second steam generated during a film heat transferring process, the secondary steam and the solution enter into the separator with larger flashing area and greater space through the large-diameter communicating pipe to improve the flashing effects.

Description

Technical field: [0001] The invention belongs to the technical field of evaporators, in particular to a split tube type falling film evaporator. Background technique: [0002] In recent years, with the successful promotion and application of the domestic tubular falling film evaporator technology, technical problems such as high steam consumption, low cycle efficiency, easy fouling, and substandard evaporation capacity of the old-fashioned natural circulation evaporator have been effectively solved. The production capacity design of the multi-effect tube falling film evaporator group has gradually increased from the initial 150T / H, 200T / H, etc. to 400T / H, 450T / H. At present, the design capacity of the largest evaporator group in China has reached 500T / H. With the continuous improvement of the evaporation design capacity, some deficiencies in the structural design of the original tubular falling film evaporator have brought some difficulties to the design, manufacture and ope...

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Problems solved by technology

[0003] (1) Insufficient space for solution flash evaporation: With the increase of evaporation design capacity, the evaporation capacity of single-effect equipment is also increasing, and the heating chamber inserted into the separation chamber occupies a part of the flash evaporation space, and the contradiction affecting the evaporation efficiency is highlighted;

[0004] (2) The lower part of the heating chamber is prone to damage: the lower part of the heating chamber is inserted into the inside of the separation chamber, so that the lower tube plate and the lower cylinder are soaked in lye and alkali vapor. Under the working conditions of high temperature and high alkali concentration, the lower part of the heating chamber In particular, the welds of the tube sheet and the heating chamber cylinder are prone to stress corrosion, resulting in alkali embrittlement, affecting the operating rate of the equipment and shortening the service life of the equipment;

[0005] (3) The condensed water outlet pipe is prone to leakage: the condensed water outlet pipe of the heating chamber is led out from the lower part of the heating chamber through the separation chamber, and the condensed water pipe is welded to the heating chamber and the separation chamber cylinder. Under the harsh conditions of alkali liquid and alkali vapor corrosion and the expansion and deformation of the heating chamber shell and the heat exchange tube, it is very easy to cause leakage of the fillet weld connecting the condensate outlet pipe and the heating chamber shell, which is extremely inconvenient for maintenance. The effect of maintenance is not good, which affects the normal operation of the equipment; the leakage of the weld seam of the condensate pipe may easily cause the steam condensate to carry alkali, affect the subsequent use of condensate, and increase the cost of production and operation

[0006] (4) Secondary steam is prone to alkali-carrying problems: the integrated structure allows the vapor-liquid separator to be arranged only in the annular space formed by the heating chamber and the separation chamber, and the arrangement area is insufficient, resulting in an increase in the workload of the vapor-liquid separator , the escape speed of the secondary steam increases, and it is easy to cause the secondary steam to carry alkali

[0007] (5) Increase the difficulty of installation and steel structure design: the equipment specifications and loads of the evaporator increase more, and the integrated structure is likely to cause a greater increase in the local loads of the steel structure, which increases the difficulty of equipment installation and steel structure design , while increasing the installation cost

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