JPS58177105A - Method for promotion evaporation in multi-stage flash evaporation apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for promoting evaporation in a multi-stage flash evaporator.

Multi-stage Fukusch evaporation equipment is used as a means of seawater desalination. It is often used. In addition to seawater desalination, it is also used to obtain clean steam from heated wastewater or hot waste water that contains impurities, and to extract clean steam from hot water that contains toxic components such as geothermal water. In particular, when used for seawater desalination, there are restrictions on flash evaporation temperature due to the problem of scale precipitation in seawater and the temperature of seawater as cooling water, and flash evaporation temperature is generally relatively low at 110°C to 30°C. .

Incidentally, multi-stage flash evaporators used as seawater desalination devices tend to become larger year by year, and as a result, the amount of seawater to be collected, ie, the flow rate of the prine, is also increasing. As the pline flow rate increases, the pline level in the multi-stage flash evaporation chamber also tends to increase, and at this time, a difference in evaporation rate occurs between the prine upper layer and the prine lower layer. However, according to conventional multistage flash evaporators, the difference in evaporation rate is not large when the evaporation temperature is 80°C or higher, but as the temperature decreases, the difference increases.
At temperatures below 50°C, the difference becomes so large that it causes the problem of suppressing evaporation. The reason for this is that the #''i evaporation pressure is small at low temperatures, so the evaporation of the lower layer grains that receives the liquid head of the upper layer grains is significantly suppressed. This is because plines with evaporation ability sink into the lower layer plines.

The present invention aims to solve such problems by promoting evaporation by means of a raised bottom or a base provided over a predetermined length in the flow direction on the downstream side of the interstage orifice of a multistage flash evaporation chamber. By providing a method for accelerating evaporation in a multi-stage evaporation device characterized by can promote the evaporation of Note that prine refers to a liquid used in a cooling system, and generally contains soluble substances.

The method of the present invention will be explained in detail below based on the drawings showing one embodiment thereof. FIG. 1 shows the main parts of a multi-stage flash evaporation device used for seawater desalination according to the method of the present invention. Evaporation chamber (2) (3) (
4) is formed. (5) is a crotch orifice provided at the lower end of the partition plate (1).

(6) is a rectangular raised bottom part provided at the bottom of each evaporation chamber (2), (3), and (4), located downstream of the interstage orifice (5), and in the flow direction of the pline (7). It is made to have a predetermined length. In addition, in the drawing, upstream evaporation chamber 2
) and the raised bottom part (6) provided in the downstream evaporation chamber (4).
) was omitted by 1°.

Strictly speaking, the position and size of the plow-shaped raised bottom part (6) in the evaporation chamber (3) are related to process conditions such as the flow rate of the guffin (7) and the steam temperature, so it is difficult to make a simple regulation. However, in this example, it was set within the following range. In other words, the flow rate is 600 to 1000t.
/m, h, evaporation temperature is 80~35℃, the location is upstream from the center of the evaporation chamber (3), and the size is 1~3 times the length of the evaporation chamber (3). The range and height ranged from 40 to 70% of the outlet brine (7) level of the evaporation chamber (3). Generally speaking, it is said that the optimum height is about 7 degrees of the length of the evaporation chamber (3), and the optimum height is about 55 degrees, which is the level of the outlet brine (7) of the evaporation chamber (3).

With this configuration, when the pline (7) is flowed as shown by the arrow in the figure, the pline (7) passes through the lower opening of the upstream partition plate (1) and is regulated by the interstage orifice dog (5). The liquid flows into the evaporation chamber (3) so as to be discharged therein, where it collides with the raised bottom (6) and a part of it evaporates. The steam is cooled and condensed by appropriate means and then used.

After the remaining prine (7) climbs over the Fi raising bottom (6), it passes through the lower opening of the downstream partition plate (1) and proceeds to the downstream evaporation chamber (4), where it is further evaporated.

Next, an experiment was conducted to determine the degree of completion of evaporation when the raised bottom part (6) was provided and when the raised bottom part (6) was not provided, and the results will be explained based on FIG. 2. FIG. 2 shows the effect of varying the evaporation temperature while keeping the pline flow rate (expressed as flow rate per unit width of the evaporation chamber) constant at 800'/m-h.

In the figure, NETD is an index indicating the degree of completion of evaporation, and is defined as the difference between the temperature of the gouffin (7) exiting the evaporation chamber (3) and the steam temperature. A smaller NETD indicates more complete steaming. As is clear from FIG. 2, the product provided with the raised bottom portion (6) according to the present invention is more comfortable than the product provided with the raised bottom portion (6).NE
TD can be made smaller. Although the difference is noticeable even around 80°C, it is clear that it is particularly noticeable at evaporation temperatures of 50°C or lower. From this, in the present invention, even when the evaporation temperature of the grains (7) becomes low and a difference in evaporation rate occurs between the upper layer and the lower layer, the grains (7) in the lower layer whose evaporation is suppressed It is clear that it is possible to prevent the infiltration of the pline (7) having evaporation ability.

3 to 5 show other embodiments in which the shape of the raised bottom portion (6) is changed. The arrows shown in the figure each indicate the flow direction of the gouffin (7). The one in Figure 3 has a slope (9) on the downstream end of the raised bottom 5 (8), and the one in Figure 4 has a slope (B) on the upstream end of the raised bottom aO. , and the one in Figure 5 has a raised bottom @
A slope Q3 is provided at both ends of the upstream side and the downstream side, and these configurations allow the grains (7) to flow smoothly and reduce flow resistance. This makes it possible to more effectively prevent the grains (7) having evaporation ability from penetrating into the grains (7) in the lower layer where evaporation is suppressed.

In FIGS. 6 to 9, a rectangular base is provided in place of the raised bottom (6). The one in Figure 6 is base Q4.
A through hole (to) is provided at the lower end of the downstream end surface for, for example, water drainage, measurement, reinforcement, etc., and the structure of the through hole (to) is such that a large amount of prine (7) and nails can pass through it. It is made impossible to do so. Even if some through holes are provided in this way, the pline (7) will not flow into the through holes in large quantities, so the same effect as the above-mentioned raised bottom part (6) can be obtained. On the other hand, the purpose can be achieved by using a through hole (G). The base (to) in Fig. 7 is constructed by removing part of the member (b) on the downstream end face at appropriate intervals in the width direction, as shown in Fig. The base part in the figure is constructed by completely removing the members on the downstream end surface. By reducing or eliminating some of the members of the base Qfe in this way, it is possible to obtain the same effects as the above-mentioned raised bottom part (6), while reducing costs.

Although each of the above embodiments has been described with a focus on desalination of seawater, it is clear that the invention can be similarly applied to geothermal water, other hot wastewater, or hot wastewater.

As described above, according to the method of the present invention, even when the evaporation temperature of the prine is high, and even when the evaporation temperature of the gouffin is low, the prine with evaporation ability sneaks into the liquid wood head of the upper layer gouffin and into the lower layer pudine whose evaporation is suppressed. Since it is possible to prevent the prine from evaporating, the evaporation of the prine can be promoted very well.

[Brief explanation of the drawing]

The drawings show an embodiment of the method of the present invention; FIG. 1 is an enlarged longitudinal sectional side view of the main parts of a multi-stage flash evaporation device according to the present invention, FIG. 2' is a diagram showing the relationship between NETD and evaporation temperature, and FIG.
5 to 5 are longitudinal side views showing other embodiments of the raised bottom, FIGS. 6 to 7 show embodiments of the base, and FIGS. 6 and 7 are longitudinal sectional side views of a rectangular base. 8 is a sectional view taken along the line AA in FIG. 7, and FIG. 9 is a longitudinal sectional side view of the rectangular base. (5)...groin orifice, (6) (s) Q(e
(6)...Raised bottom, (7)...Pline, Q10
(to)... Weir agent Yoshihiro Morimoto Figure 3 7 Figure 4 Figure 5 Figure 7, Figure β 6 2nd drawing and construction procedure amendment (1980 6) April 4th, 2017, Mr. Commissioner of the Japan Patent Office, 1. Indication of the case, Patent Application No. 60090 of 1982, 2. Name of the invention, Method for promoting evaporation in a multi-stage flash evaporator, 3. Person making the amendment. Relationship with the case. Name of the patent applicant. (511) Hitachi Zosen Co., Ltd. 4, Agent 5, Date of (Shipping date) Showa year
Day 6, Number of inventions increased by amendment 7, Column for detailed explanation of the invention in the specification subject to amendment Contents of the amendment ■ Column for detailed explanation of the invention in the specification (1) Page 2, line 19 It says "to be in the lower layer" and "to be in the lower layer" K
correct. (2) Delete the line 10th to 12th page of page 3 that says, "Grinds include...". (3) On page 3, line 16, ``principal part'' should be corrected to ``principal part.'' (4) On page 5, lines 18 to 19, "steam" is corrected to "evaporation." (5) On page 6, lines 7 to 8, the phrase "in the lower layer pline (7)" is corrected to "the lower layer K". (6) In the first line of page 7, the phrase ``in the lower layer of grain (7)'' is corrected to ``in the lower layer to be done''. (7) In the 10th line of page 8, the phrase "in the lower grain" is corrected to "in the lower layer". (2)

Claims (1)

[Claims] 1. A method for promoting evaporation in a multi-stage flash evaporation device, characterized in that evaporation is promoted by a raised bottom or a base provided over a predetermined length in the pline flow direction on the downstream side of the crotch orifice of the multi-stage flash evaporation chamber.