SU899049A1 - Contact tray for mass-exchange apparatus - Google Patents

Description

I

The invention relates to contact devices designed for heat and mass transfer processes, for example, rectification processes, absorption, heat exchange, liquid gas with direct contact, especially for large diameter columns.

Sieve plates are known with various forms of overflow devices and partitioning elements: triangular, rectangular, hexagonal, circular, etc. or combinations of overflow devices and elements of various configurations. ,

The disadvantage of these plates is that, since the column section has the shape of a circle, none of the proposed configurations of the sectioning elements allows the VPI-JQ to cross section of the column without dead zones around its walls. Filling these dead zones with sectioning elements of another configuration

leads to a different distribution pattern of the fluid in the near-wall region, which accounts for a significant proportion of the entire cross-section of the dish.

A known design of a sieve tray for a large diameter column with slotted overflows of rectangular cross section. I its construction and partitioning is ensured by the overflow partitions themselves, and only in the direction of one coordinate, the slotted overflows of the adjacent plates are mutually perpendicular 2.

The disadvantage of this construction is the presence of elongated perforated sectional elements in which a wave of liquid can move from one wall of the column to another, i.e. here the principle of longitudinal-cross sectioning is not provided. On the other hand, such a constructive solution does not ensure equal conditions from the point of view of the residence time of the liquid on the plate and

its contact with gas. Moreover, for a certain part of the liquid in the area close to the overflow of overflows, the residence time on the plate is very mapo.

Closest to the invention is a plate for contacting liquids and gases, consisting of a base with contact elements, partitioned by annular and radial partitions into several elements, in the center of which overflow devices are installed, having reflective disks 3.

However, the movement of the fluid in the bubbling zone within the element from the partitioned partitions to the central web does not ensure its sufficiently good distribution due to the accepted configuration of the partitioning elements. The design feature of the well-known dish is the large height of the overflow device, and, consequently, the long inter-dish distance. The impact of the liquid on the reflective disk and the vertical partitions cause additional splash guards, which leads to a decrease in efficiency. - In addition, the known plate works in a narrow range of loads, in fluid: from choking to fluid flow, at which the fluid stops filling the entire overflow section, i.e. at low loads, the gas can go through the overflow device, and the liquid falls through a part of the holes, in addition, the plate will not work the entire surface. So the length

liquid paths in this CONSTRUCTION 5

therefore, the residence time depends on its consumption. It also reduces the efficiency of the plate.

The purpose of the invention is to intensify the process by improving the distribution of liquid and reducing its gradient across the plate.

The goal is achieved by the fact that the overflow pipes are located on the border of adjacent sections and the radial partitions pass through their center.

It is advisable to supply overflow pipes with perpendicularly arranged radial partitions with additional perforated partitions.

It is advisable to supply each overflow pipe with a hydraulic lock, made in the form of a glass, and a conical baffle, perforated in the upper part and installed relative to the hydraulic lock glass at a distance of (0.1–1.0), where d is the diameter of the overflow device, d, outer diameter of the bump stop.

FIG. 1 shows solid lines in the plan of the overlying plate, and dotted lines show the underlying plate with correspondingly displaced overflow structures (the streaks indicate the direction of fluid motion in the elements); Fig, 2 adjacent plates installed in the housing of the apparatus, a general view.

The plate contains a base 1, annular partitions 2, overflow radial perforated partitions 3, overflow pipes 4, perforated by partitions 5. Overflow pipes 4 have baffle cones 6 and end with cylindrical hydraulic locks 7, in the form of glasses, excluding gas breakthrough through overflow. The plate can be equipped with contact elements, holes, valves, caps, etc.

The plate works as follows.

The liquid flowing from the top plate through the overflow pipe 4 enters the hydraulic lock 7, flows out onto the underlying plate and spreads into two streams.

Further, the whole process is repeated from plate to plate. The gas moves through the apparatus in counterflow, bubbling through a layer of liquid onto the dish.

Example: The proposed plate design passes hydrodynamic tests in a column of 2000 mm with perforated plates having 30 overflow devices, the path length of the fluid in separate cells is 210 mm. The tests are carried out at an OS of 70 m / m HW of 1.8 m / s and show that the proposed plate design works evenly over a wide range of loads. The buildup of foam on the plate and the gradient of the cloth are almost completely absent.

Claims (3)

Example 2: Kinetic tests are carried out on a column of 0900 mm on a methanol-water system, Oigcha-tmr plates have nine overflow devices, d: the path of the well; 1, 180 mm. With loads of fluid up to 150 m / m h, the efficiency of the plate is stable,, 85-0.95 according to Murphy. The study of fluid distribution shows that there is practically no flow of fluid between the elements and complete modeling is observed. In the proposed plate, the fluid is evenly distributed, its gradient is absent on the plate and foam build-up, the same residence time of the fluid in all sections is provided, the intertrail distance decreases and reduced entrainment. Overflow pipes can be displaced in adjacent plates along the circumference connecting the centers of the respective overflow devices by an angle not exceeding 90. The advantage of the proposed construction is also that, given the value of the length of the fluid path, you can create a plate with any necessary the degree of mixing, which makes it possible to use this device quite widely for various processes and devices with almost no restriction on their size, since the efficiency of the column as a whole reproduces the efficiency individual elements, i.e. the scaling factor is close to one. In addition, the throughput capacity of the saucer plate for liquid is 45% compared with the known value. This is achieved by locating in the overflow device a perforated partition perpendicular to the radial partition. The presence of conical chippers in the overflow pipes eliminates the entrainment of fluid from the water seal, allowing an increase in the gas load by 25%. The presence of perforations in the upper part of the cones for gas outlet improves the overflow operation. Compared with the known inter-tray entrainment, it is reduced by 18%. In addition, these constructive methods allow to reduce the distance between the plates to 200 m versus 600 mm and is well known because the mode of operation of the plate does not depend on the level of liquid D on the overflow device, and hence on its height. This makes it possible to reduce the size and intensity of expensive heat and mass transfer equipment, which is especially important for cryogenic apparatuses, which are mainly made from alloyed steels. Claim 1. A contact plate for mass exchangers in the system gas (vapor) -liquid containing bases with contact elements, perforated partitions arranged around the ring and radially, dividing the base into sections, equipped with overflow pipes, characterized in that In order to intensify the process by improving the distribution of the liquid and reducing its gradient across the plate, the overflow pipes are located on the border of adjacent sections and the radial partitions pass through their center. 2. The plate according to claim 1, which is designed to increase the liquid load on the overflow pipes, improve its degassing in it and eliminate stagnant zones on the plate, the overflow pipes are provided with perforated perpendicular to the radial partitions partitions. 3. The plate according to claim 1, characterized in that, in order to eliminate the hydraulic oil discharge and increase the load on the gas, each overflow pipe is equipped with a water seal, made in the form of a glass, and has a conical chipper punched in the upper part, the diameter of the overflow pipe dj, established with respect to the water seal cup at a distance equal to (0.1–1.0), d is the outer diameter of the bump stop. Sources of information taken into account in the examination 1. Report MIKM number 2386, 1974. 2.Prospekt firm Union Carbide, M., 1974. 3. The author's certificate of the USSR If 511958, cl. B 01 D 3/30, 1971.