DE2016908A1 - Multi-stage flash evaporator - Google Patents

Description

April 6, 1970 ipat / 1578 / Y / Pr

Multi-stage flash evaporator

The invention "relates to a multi-stage flash evaporator, "consisting of an elongated housing with vertical to the longitudinal axis of the housing, the individual steps delimiting partition walls, in the upper area of each step Condenser tubes through which the raw liquor flows and weirs overflowing from the evaporating liquor in the lower area are provided are. Flash evaporators of this type are used in particular the production of fresh water from seawater, to the extent due to the advancing civilization and the population explosion to be able to meet the increasing demand for fresh water.

The raw liquor (e.g. sea water) flows through the Condenser tubes in the individual stages, each of which has a slightly higher temperature than the previous stage prevails. Then the warmed up raw liquor is further heated up by an external heat source and in the opposite direction (falling pressure and falling temperature) through the lower areas of the individual stages. The fresh water vapors (vapors) produced in the individual stages are combined down on the condenser tubes. The distillate produced in this way drips into bowls located under the condensers and is removed from there from the stage with the lower pressure and finally pumped out into a common distillate tank. With previously known Relaxation evaporator systems are located on the condenser forming tube bundle either perpendicular to the longitudinal axis of the housing (DAS 1 258 559; short tube design) or - to costly Avoid diverting the bundle through both side walls of the individual steps, which would cause pressure losses - parallel to the longitudinal axis of the housing (long tube design). The weir in each step is at both

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Embodiments arranged perpendicular to the longitudinal axis of the housing, so that the length of each weir is the width of the housing is equivalent to. The main disadvantage that adheres to these previously known flash evaporators "is that the plant costs are very high compared to the performance, so that high water prices result.

The invention is based on the object in multi-stage expansion evaporators, consisting of an elongated housing with lying perpendicular to the longitudinal axis of the housing, the individual Partition walls delimiting steps, with one in the upper area Condenser tubes through which the raw liquor flows in each stage and weirs overflowing with the evaporating liquor in the lower area are intended to improve the ratio of performance to investment costs.

This object is achieved according to the invention in that in a flash evaporator of the type described, at least two Weirs are provided at each stage. The main advantage the invention consists in that a trained according to the invention Flash evaporators of the best order of magnitude Provides performance that was previously only provided by much larger and therefore more expensive flash evaporators could.

For the performance of a flash evaporator, the is as specific The characteristic value referred to as the lye load, which is the quotient of the amount of lye flowing through the system every hour (in tons) and the total length of the weirs (in meters). The maximum power of a flash evaporator is at a certain specific alkali load, i. H. the power has its maximum at a certain layer height the lye when overflowing over the weirs. The extension the weirs in the manner according to the invention thus enables one Increase in the amount flowing through the system in the unit of time

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Amount of lye, without the specific lye load or the Layer height of the lye when overflowing the weirs above "the value addition, in which the evaporator has its maximum capacity, to have to enlarge. This is a significant increase in performance connected, so that significantly more fresh water can be poduziert with approximately the same system costs.

For flash evaporators with perpendicular to the longitudinal axis of the housing arranged condenser tubes, it can be advantageous in each stage two also perpendicular to the longitudinal axis of the housing to provide horizontal weirs, whereby a substantial increase in the length of the weir is achieved.

With expansion evaporators with parallel to the longitudinal axis of the housing lying condenser tubes, in which the individual stages are made relatively narrow, is within the scope of the invention proposed at least one weir parallel to the longitudinal axis to arrange the housing. This also increases the Weir length achieved, which brings the advantages already described.

The diameter of the pipe sections forming the capacitor has hitherto been the same in all stages for manufacturing reasons chosen large. In the case of flash evaporators that are made from process engineering and for cost reasons with combined throughput, operation of the cooling water and circulation of the lye work, however, other condensation surfaces are often required in the flow section than in the circulation section. Nevertheless, one has in all levels the same condenser tube bundle, i.e. the same condensation area, and the resulting oversizing of the condensation surfaces in a few stages. in purchase taken. In the context of the invention it is therefore proposed that that in the studies in which smaller condensation areas than in the other stages are required, condenser tubes with larger diameters than in the other stages are provided. : ■■■■■■. ■■ .-. _ 4 -

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This measure also brings about a significant reduction in costs Flash evaporator systems.

Further advantages and details are to be found with reference to in the figures 1 to 6 illustrated embodiments are explained. Show it:

1 shows a plan view of part of an expansion evaporator designed according to the invention with perpendicular to the Longitudinal axis of the housing lying condenser tubes,

FIG. 2 shows a longitudinal section through the expansion evaporator according to FIG. 1,

3 shows a plan view of a part of one designed according to the invention Relaxation evaporator with parallel to Longitudinal axis of the housing lying condenser tubes,

FIG. 4 shows a cross section through the expansion evaporator according to FIG. 3,

5 shows a plan view of part of a flash evaporator as in Fig. 3 with a modified arrangement of the honor and

FIG. 6 shows a cross section through the expansion evaporator according to FIG. 5.

In the part of the expansion evaporator shown in FIGS. 1 and 2 1, the partition walls 4 are arranged within the housing 2 perpendicular to the longitudinal axis 3 of the housing 2, which the Divide housing 2 into individual stages 5a to 5e. In the upper area of the steps 5a to 5e are each a perpendicular to The condenser tube bundle 6 lying along the longitudinal axis 3 of the housing 2 and a moisture separator 7 are arranged. To a sufficient To accommodate a large capacitor area, the steps 5a to 5e are relatively wide and not very deep. the

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The condenser tube bundle 6 is connected to one another via collector 8 and lines located outside the housing 2

In the lower area of the individual steps 5a to 5e there are two weirs that are perpendicular to the longitudinal axis 3 of the housing 2 and 11 provided. Together with one arranged above the weirs Baffle plate 12, weirs 10 and 11 form a tunnel, whose inner part is in connection with the previous stage = This connection is either through outside the housing 2 guided pipes 13 (see connection of stages 5a and _5b) or pipes lying inside the housing H (see e.g. the connection between stages 5b and 5c). The weirs 10 and 11 are thus in the direction of the arrows 15 Overflowed by the raw liquor. To achieve favorable flow conditions the guide plates 16 are also provided. By installing throttle devices 13a in the pipelines 13 external control processes (such as water level control in the stage or bypassing a relaxation stage) be made possible.

In the embodiments shown in Figures 3 to 6, the condenser tubes 6 are each parallel to the longitudinal axis 3 of the housing 2. To accommodate the condenser tube bundle section located in the individual stages 5a to 5e, the stages are relatively long, but not very wide, according to requirements. In order to achieve the necessary large weir length in these stages, the weirs 17 are arranged parallel to the longitudinal axis 3 of the housing 2 according to the exemplary embodiment according to FIGS. The weirs 17 each form, with the baffle plate 18 and the side wall of the housing 2, a tunnel with an upper slot opening on one side. The weirs are each arranged offset in the steps so that the interior of the tunnel can be connected to the preceding step in a simple manner via an opening, not shown, near the floor in the partition 4.

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In the exemplary embodiment according to FIGS. 5 and 6, one is parallel to the longitudinal axis 3 of the housing 2 lying tunnel arranged centrally. This tunnel is formed by the two weirs 19 and 20 and from the baffle plate 21. This results in a considerable increase in the length of the weir. With this arrangement the guide plates 16 are also provided to achieve favorable flow conditions. In addition, this can also be used for the purpose of improved Level control ability between the relaxation levels a pipeline arranged outside as in the exemplary embodiment be provided according to Figures 1 and 2

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Claims (11)

2018 308 co φ m - 7 - April 6, 1970 Tpat / 1578 / Y / Fr PATENT CLAIMS 1. Multi-stage flash evaporator, consisting of an elongated Housing with partitions which are perpendicular to the longitudinal axis of the housing and delimit the individual steps, wherein in the upper area of each stage the raw liquor flows through the condenser tubes and in the lower area of the evaporating one Weirs overflowing with lye are provided, characterized in that at least two weirs (10, 11; 19, 20) are provided in each stage (5a to 5e). 2. Flash evaporator according to claim 1 with arranged perpendicular to the longitudinal axis of the housing condenser tubes, characterized characterized in that in each stage (5a to 5e) two also perpendicular to the longitudinal axis (3) of the housing (2) horizontal weirs (10, 11) are arranged. 3. Flash evaporator according to claim 2, characterized in that that the weirs (10, 11) together with a baffle plate (12) arranged above the weirs ^ (10, 11) create a tunnel 4. Flash evaporator according to claim 3, characterized that the inside of the tunnel with the previous stage over outside of the housing (2) of the relaxation Evaporator (1) guided pipes (13) connected is. 5. Flash evaporator according to claim 4, characterized that by installing throttle devices (13a) in the pipelines (13) to be operated from the outside Control processes (such as water level control in the stage or bypassing a relaxation stage) are made possible. 109843/1540 201 (5308 OO OD ITJ BABC <Ä> CK - 8th 6. Multi-stage flash evaporator, consisting of an elongated Housing with partition walls that are perpendicular to the longitudinal axis of the housing and delimit the individual steps, being in the upper part of each stage of the raw liquor condenser tubes through which there is a flow and weirs overflowing with the evaporating liquor are provided in the lower area, with condenser tubes lying parallel to the longitudinal axis of the housing, characterized in that in each stage (5a valley 5e) at least one also in parallel provided weir (17) lying to the longitudinal axis (3) of the housing (2) is. 7 · Expansion evaporator according to claim 6, characterized in that the weirs (17) in the individual, successive stages (5a to 5e) staggered ο rdne t are ind. 8. expansion evaporator according to claim 6, gekennzei chnet by two centrally arranged weirs (19, 20). 9 «expansion evaporator according to claim 8, characterized in that the weirs (19, 20) together form a tunnel with a baffle plate (21). 10. Flash evaporator according to claims 4 or 5 and 8, characterized in that for the purpose of improved Step regulating capability between the expansion stages (5) is provided by an outside pipeline (13) is. 11. Flash evaporator according to one of the preceding claims , characterized in that guide plates (16) are provided within the individual steps (5a to 5e) are. 1-09843 / 1540 12; Relaxation vaporizer make one of the preceding claims, characterized in that the capacitors (6) in the individual stages (5a to 5e) are formed from ears, which depending on the in a certain Level required area of communication different diameters exhibit. 109843/1540 Blank page