CN-122006277-A - Multistage vapour-liquid separation system of horizontal pipe falling film evaporator

CN122006277ACN 122006277 ACN122006277 ACN 122006277ACN-122006277-A

Abstract

The invention discloses a multistage vapor-liquid separation system of a horizontal tube falling film evaporator, which belongs to the technical field of multi-effect distillation and comprises an evaporator and a multistage vapor-liquid separator, wherein a condensation side end socket of the evaporator is arranged at the condensation side of the evaporator, the multistage vapor-liquid separator is embedded in the upper part of the condensation side end socket of the evaporator and comprises an end socket baffle plate, a corrugated baffle plate, a defoaming screen and a vapor-liquid baffle plate which are sequentially arranged from inside to outside, the end socket baffle plate divides the condensation side end socket of the evaporator into an upper part and a lower part, the upper part is a secondary vapor outlet area output by the evaporator, secondary vapor carrying liquid drops output by the evaporator is sequentially separated by turbulent flow and foldback separation in a cylinder of the evaporator, the corrugated baffle plate separation and the defoaming screen, and then enters the next-effect evaporator, and the lower part is a condensed water collecting outlet area output by the evaporator. The invention can realize the high-efficiency optimal vapor-liquid separation effect under the working condition that the vapor flow speed is 1-5.5 m/s.

Inventors

SUN WENXU
LIU CHANGCHAO
ZHANG HAILUN
ZHANG YUANMIN
JIA LEI

Assignees

山东大学

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. The multistage vapor-liquid separation system of the horizontal tube falling film evaporator is characterized by comprising an evaporator and a multistage vapor-liquid separator; The multi-stage vapor-liquid separator comprises an end enclosure partition plate and a corrugated baffle plate, a defoaming silk screen and a vapor-liquid baffle plate which are sequentially arranged from inside to outside, wherein the end enclosure partition plate divides the evaporator condensation side end enclosure into an upper part and a lower part, the upper part is a secondary vapor outlet area output by the evaporator, and the lower part is a condensed water collecting outlet area output by the evaporator; the pressure difference exists between the inside of the evaporator cylinder and the outlet area at the condensation side, so that the secondary steam carrying liquid drops enters the secondary steam outlet area after turbulent flow and foldback separation in the evaporator cylinder, and then sequentially passes through the corrugated baffle separation and defoaming screen separation of the multistage vapor-liquid separator and enters the next-effect evaporator.
2. The horizontal tube falling film evaporator multistage vapor-liquid separation system as set forth in claim 1 wherein said evaporator condensation side head comprises a head cylinder, a condensation side flange, a vapor inlet side flange, the evaporator cylinder is connected with said condensation side flange, said condensation side flange and said vapor inlet side flange are respectively disposed on two sides of said head cylinder, said vapor inlet side flange is connected with the next effect evaporator cylinder; The multistage vapor-liquid separator is of an arc arch structure and is embedded into the upper part of the interior of the seal head cylinder of the condensation side seal head of the evaporator, a reinforcing rib is arranged in the condensation side flange, a seal head baffle plate of the multistage vapor-liquid separator is welded with the upper side surface of the reinforcing rib of the condensation side flange, two side surfaces of the seal head baffle plate are respectively welded with the inner wall surface of the seal head cylinder, and an inclination angle alpha exists between the seal head baffle plate and a horizontal plane.
3. The multistage vapor-liquid separation system of a horizontal tube falling film evaporator according to claim 2, wherein the minimum value calculation formula of the inclination angle alpha between the end enclosure partition plate and the horizontal plane is: ; Wherein, the The minimum value of the inclination angle is represented by m, the equivalent mass of liquid drops separated from the vapor-liquid separation is represented by R, the radius of spherical liquid drops is represented by R, the pressure difference between the inlet and the outlet of the vapor-liquid separator is represented by P, the shearing force correction coefficient is represented by k=0.5-1, For the viscosity of the secondary steam, the viscosity of the secondary steam is the same as that of the primary steam, G is gravity acceleration, which is the secondary steam flow rate.
4. The multistage vapor-liquid separation system of the horizontal tube falling film evaporator according to claim 2, wherein the corrugated stainless steel folded plate is used as baffle blades of a corrugated baffle plate, is a cambered plate with a convex surface formed by a convex in the middle and inclined surfaces on two side surfaces of the convex, all baffle blades are sequentially and uniformly arranged in sequence according to a set interval, and the heights of the baffle blades from two sides to the middle are sequentially and symmetrically increased, so that the upper end and the lower end of all file blades are respectively connected with the inner wall of a seal head cylinder and the upper surface of the seal head baffle plate; the arc surface at the top of the defoaming screen is tangent to the inner wall of the seal head cylinder, and the defoaming screen adopts a DP efficient screen with a set wire diameter and a set hole pitch.
5. The multistage vapor-liquid separation system of the horizontal tube falling film evaporator of claim 4, wherein the secondary vapor carrying liquid drops output by the evaporator is subjected to first-stage vapor-liquid separation through turbulent flow and foldback separation in an evaporator cylinder, wherein the secondary vapor carrying liquid drops forms air flow in the process of flowing to a condensing side outlet, and the liquid drops are separated from the vapor under the action of air flow disturbance and liquid drop gravity by pressure difference existing in the interior of the evaporator cylinder and the condensing side outlet area, so that the first-stage vapor-liquid separation is completed; After entering the corrugated baffle plate, the secondary steam carrying liquid drops sequentially impacts three impact surfaces, the liquid drops are separated from the steam after impact, and the separated liquid drops flow back to the evaporator along the inclined end socket baffle plate to finish the second-stage steam-liquid separation; The secondary steam after passing through the corrugated baffle plate enters a defoaming screen, tiny liquid drops mixed in the secondary steam are subjected to vapor-liquid separation through the defoaming screen, and the separated liquid drops flow back to the evaporator along the inclined end socket baffle plate, so that third-stage vapor-liquid separation is completed.
6. The multistage vapor-liquid separation system of a horizontal tube falling film evaporator according to claim 4, wherein the corrugated baffles are used for separating and removing large purified water drops, the optimal working flow speed range is 3.5-5.5 m/s, the spacing between the baffle blades correspondingly arranged is 30-50 mm, and the optimal spacing between the baffle blades in the corrugated baffles is determined according to the secondary steam flow speed.
7. The multistage vapor-liquid separation system of the horizontal tube falling film evaporator according to claim 4, wherein the defoaming screen is used for separating and removing small purified water drops, the optimal working flow speed range is 1-3.5 m/s, the corresponding wire diameter is 0.15-0.25 mm, the hole pitch is 150-200 μm, and the wire diameter and the hole pitch parameters of the defoaming screen are determined according to the secondary steam flow speed.
8. The horizontal tube falling film evaporator multi-stage vapor-liquid separation system as set forth in claim 4 wherein determining the thickness of the corrugated baffle and the defoaming screen in the multi-stage vapor-liquid separator based on the secondary vapor flow rate comprises: when the flow rate of the secondary steam is 1-3 m/s, ; When the flow rate of the secondary steam is 3-4 m/s, ; When the flow rate of the secondary steam is 4-5.5 m/s, ; Wherein, the Is the thickness of the vapor-liquid separator, 、 The thickness of the corrugated baffle and the defoaming screen are shown respectively, 。
9. The horizontal tube falling film evaporator multi-stage vapor-liquid separation system of claim 1, wherein the corrugated baffles and demister screens provide a liquid droplet removal efficiency All are calculated by an inertial collision efficiency model, wherein the inertial collision efficiency model is as follows: ; Wherein, the The stokes number is represented by the number, In order to achieve a drop density, In order to be of the equivalent diameter of the droplet, For the flow rate of the steam, For the viscosity of the steam, Is the corrugated baffle blade spacing or the defoaming screen aperture.
10. The multistage vapor-liquid separation system of the horizontal tube falling film evaporator according to claim 1, wherein the vapor-liquid baffle is in a strip shape, the length of the vapor-liquid baffle is consistent with the inner diameter of the seal head cylinder, the width of the vapor-liquid baffle is adjustable, and the vapor-liquid baffle is arranged at the tail end of the defoaming screen and is used for preventing separated liquid drops from being blown into the next evaporator by airflow.

Description

Multistage vapour-liquid separation system of horizontal pipe falling film evaporator Technical Field The invention belongs to the technical field of multi-effect distillation, and particularly relates to a multistage vapor-liquid separation system of a horizontal tube falling film evaporator. Background The hot-pressing multi-effect distilled water machine is a new-type high-effective preparation equipment for medical injection water, and its horizontal tube falling film evaporator is used as an important component of said equipment, mainly includes pure steam inlet system, purified water liquid-distributing system, vapour-liquid separation system, distilled water system and distilled water system, etc. the main working principle of said evaporator is that the high-temperature high-pressure pure steam can be fed into the interior of heat-exchange tube of evaporator, at the same time the pure water can be sprayed into the exterior surface of heat-exchange tube to form uniform liquid film, the pure steam in the interior of tube can be heat-released and condensed into distilled water, the purified water outside the tube can be heat-absorbed and evaporated to produce secondary steam, the secondary steam with liquid drop can be passed through vapour-liquid separation system, separated out liquid drop into pure steam, then fed into next-effect evaporator. The indexes such as conductivity, bacterial endotoxin and the like of the injection water are core indexes for evaluating the water quality of a distilled water machine aiming at the prepared medical injection water, and the indexes are closely related to a vapor-liquid separation system in an evaporator. Based on the working principle, the secondary steam generated by the evaporator can carry a large amount of purified water droplets, because the indexes of the conductivity, bacterial endotoxin and the like of the purified water can not meet the requirement of injection water, if the purified water droplets enter distilled water of the next-effect evaporator along with the secondary steam, the quality of water produced by equipment can be seriously influenced. Therefore, it is necessary to remove the droplets of purified water carried by the secondary steam before it leaves the effect evaporator using a vapor-liquid separation system. The vapor-liquid separation system is an important component in a horizontal tube falling film evaporator, and is a device for separating vapor and liquid mixture by a physical mechanism by utilizing the density difference of vapor-liquid two phases. In addition, the single wire mesh demister has higher flow speed requirement on the secondary steam, the optimal vapor-liquid separation effect can be achieved only when the flow speed of the steam is 1-3 m/s, the fluctuation of the flow speed of the steam is easy to be caused due to the fluctuation of working conditions and the like in actual conditions, the flow speed of the steam is more than 3m/s, the vapor-liquid separation effect is obviously reduced, the fluctuation of the conductivity of water produced by the system is larger, and the production quality, the equipment operation stability, the industry compliance and the like of the subsequent medical injection water are negatively influenced. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a multistage vapor-liquid separation system of a horizontal tube falling film evaporator, which is characterized in that through designing turbulent flow and foldback separation in an evaporator cylinder and multistage separation modes of a multistage vapor-liquid separator, simultaneously optimizing parameters of each component, improving vapor-liquid separation effect, realizing high-efficiency vapor-liquid separation under the working condition of 1-5.5 m/s of steam flow rate, improving the quality stability of water for injection and solving the problems of limited separation effect and poor adaptability to flow fluctuation of a single silk screen demister in the prior art. In order to achieve the purpose, the invention provides a multistage vapor-liquid separation system of a horizontal tube falling film evaporator. A multistage vapor-liquid separation system of a horizontal tube falling film evaporator comprises an evaporator and a multistage vapor-liquid separator; The multi-stage vapor-liquid separator comprises an end enclosure partition plate and a corrugated baffle plate, a defoaming silk screen and a vapor-liquid baffle plate which are sequentially arranged from inside to outside, wherein the end enclosure partition plate divides the evaporator condensation side end enclosure into an upper part and a lower part, the upper part is a secondary vapor outlet area output by the evaporator, and the lower part is a condensed water collecting outlet area output by the evaporator; the pressure difference exists between the inside of the evaporator cylinder and the outlet area at the condensation sid