MXPA00004715A - Liquid dispenser for oscillating distilling column, and corresponding distilling column - Google Patents

Abstract

The invention concerns a liquid dispenser comprising:a primary dispenser (13) comprising liquid dispensing openings defining N1 first compartments (22) each provided with means (10, 11) for supplying liquid;and a secondary dispenser (14) arranged beneath the primary dispenser (13) comprising a basin with an open-worked perforated base taking up substantially the whole section of the distilling column (2), said basin being subdivided by partitions (25) into N2 second compartments (24), with N2>N1. The invention is useful for producing oxygen on offshore floating terminals or drilling platforms.

Description

LIQUID DISTRIBUTOR FOR OSCILLATING DISTILLATION COLUMN, AND ITS CORRESPONDING DISTILLATION COLUMN Field of the Invention The present invention relates to a liquid distributor for oscillating distillation column. It applies in particular to air distillation columns shipped on floating structures such as offshore oil rigs or vessels. Background of the Invention Oil rigs in the sea produce residual bases. For economic and environmental reasons, it is increasingly necessary to recover these gases. One method is to convert them into heavier hydrocarbons, in liquid form and therefore more easily transportable, through the Fis cher-Trops ch procedure, which consumes large amounts of oxygen. It would therefore be interesting to be able to ship an air distillation column on a platform or a vessel, but the proper functioning of such equipment faces REF 120240 serious difficulties. For example, a first imperative is that the liquid be evenly distributed in the upper part of the column over the entire section of the column, despite the oscillations of its axis caused by the waves.

Description of the invention The object of the invention is to provide a liquid distributor whose operation is very insensitive to such oscillations. For this purpose, the object of the invention is a liquid distributor for oscillating distillation column, characterized in that it comprises: a primary distributor with liquid distribution openings and delimiting NI first compartments, with N _> 2; liquid-balanced feeding of each of the first compartments, and - a secondary distributor arranged under the primary distributor and comprising a bucket with perforated bottom openings that occupies almost the entire section of the distillation column, this tank being subdivided by partitions in N2 second compartments, with N2> NI; - the ratio of the area of each second compartment to the sum of the sections of the primary distributor openings that feed it almost constant from one second compartment to another. the invention may comprise one or more of the following characteristics: - all seconds c The compartments have almost the same area and the same drilling rate; - the number NI is less than 5 and the number N2 of the order of several tens; the primary distributor comprises a primary cuvette whose perforated bottom has the same configuration as that of the secondary cuvette and is superimposed on the latter; said feeding means comprise a phase separator and a supply conduit connected upwards with the lower part to this separator and downwards with tubes that are perforated to lead from each of the first compartments, being the ratio of the area of a first compartment with the sum of the sections of the corresponding perforations of the tubes constant from one first compartment to another; - the tubes are punched at adjacent points of the supply duct and contain holes adjacent to the central axis of the distributor; - said feeding means comprise a phase separator and perforated tubes connected to adjacent points of the lower part of the separator. The invention also relates to a distillation column comprising a distributor as defined above. In an embodiment of the distillation column, said liquid distributor is disposed at a first level of the column, in particular at the top thereof, which comprises, on at least a second level, a second level. liquid distributor as defined above.

Description of the Figures In the following, an embodiment of the invention will be described with reference to the appended drawing, in which: - Figure 1 schematically represents an oscillating distillation column equipped with two liquid distributors according to the invention, shipped on a floating structure; Figure 2 represents schematically, on a larger scale and in section according to line I-I of Figure 3, the distributor of the upper part of the distillation column of Figure 1; Figure 3 is a plan view of this distributor, and - Figure 4 is a sectional view taken along the line IV-IV of Figure 2. The distributor 1 shown in the Figures 2 to 4 is intended to be mounted on top of a distillation column 2. of air, schematized in Figure 1 as a pressure column of a double column of distillation of air. The column 2 is fixed to a floating structure 3, schematized in Figure 1, like the medium pressure column of the double distillation column (not shown). In Figure 1 only the elements useful for the understanding of the present invention are represented, but the double column comprises all the classical elements in the art. More particularly, the column 2 is subdivided into an upper section of distillation 4 and a lower section of distillation 5, both constituted by corrugated-crossings. As it is well known, such a coating comprises a superposition of sections or packages 6 of corrugated-corrugated coating, each with the shape of a cylindrical disc that occupies the entire section of the column. Each pack 6 is constituted by a stack of corrugated bands with oblique waves. Each band comprises a vertical general plane, all the bands have the same height and the waves are alternately inclined in one direction and the other from one band to the next. In this way, the waves of the adjacent bands touch on a large number of intersection points. In addition, the packages 6 are angularly offset by 90 ° from one package to the other with respect to the general axis of the column. Above the upper section 4, the column contains a distributor 1 as described above, which is the distributor of the upper part A of the column. Below the section 4 and above the distillation section 5 there is arranged a second analogous distributor constituting an intermediate distributor IB. In service, the "lean liquid" (almost pure nitrogen removed at the top of the medium pressure column) coming through a feed line 7, and released at the pressure of column 2 on a release valve 8, is introduced into a phase separator 9. The liquid collected in the latter is introduced, by means of a supply manifold 10 connected to the lower part of the separator, into two parallel tubes 11 each containing two lower holes 111. • These two The tubes are arranged in the upper dome 102 of the column and constitute the liquid feeding means of the distributor IA. The distributor 1A distributes this liquid in the entire sec- tion of the upper package 6 of the distillation section 4, in a manner that will be described later. The liquid coming from this section 4, enriched in oxygen, falls, over the entire lower surface of this section, on the intermediate distributor IB. In addition, the "rich liquid" of the same composition (air enriched in oxygen, collected in the bucket of the medium pressure column) from the medium pressure column through a duct 12, is added to this liquid by means of a valve assembly of release 8-phase separator 9-collector 10-tubes 11 identical to that described above. The whole of the liquid is redistributed by the distributor IB in the entire section of the column, to form the. reflux of the lower distillation section 5. The structure of the distributors ÍA and IB will be described below with reference to Figures 2 to 4. The distributor IA is constituted by two parts, namely a primary distributor 13 and a secondary distributor 14. arranged below and feeding means 9 to 11 already mentioned.The primary distributor 13 is constituted by an open-topped basin, with a horizontal bottom 15 and a cylindrical peripheral wall 16 that rises on this bottom. six lights 17 of elongated shape according to the direction parallel to the tubes 11, which leave free on the one hand a peripheral annular crown and on the other hand, five bands parallel to said direction.This crown and these bands are perforated by a large number N of holes 18, with a sufficient diameter to avoid any risk of plugging by impurities contained in the liquid to be distributed. The number N is typically of the order of 1000 to 3000 for a column of 4 m in diameter. Each light 17 is entirely bordered by an upward vertical wall 19, which delimits with the peripheral wall 16 five rectilinear gutters 20 of the aforementioned strips, and a peripheral annular gutter 21 communicating with all the gutters 20. In addition, the basin it is subdivided into four compartments 22 of the same area by "two vertical partitions 23 perpendicular to each other, which are cut according to the central axis XX of the tray, which coincides with the central axis of column 2. One of the partitions 23 It passes through the middle gutter 20. The tubes 11 are adjacent to each other and are arranged at the lead of the third gutter 20, on both sides of the partition 23 that divides it, with a hole 111 for each one that opens into each of the walls. corresponding compartments 22, next to the intersection of the partitions 23. In a variant, there could be several trades per compartment and possibly more than two tubes 11, being essential for a The sum of the sections of the orifices that open into each compartment is the same, and, on the other hand, that all the holes are close together to remain at close levels when the column is inclined. The secondary distributor 14 is identical to the primary distributor 13, with two differences. On the one hand, partitions 23 are suppressed. On the other hand, the gutters 20 and 21 are subdivided into a number of secondary compartments 24 much greater than four by a set of vertical partitions 25 extending between the walls 19 and between these and the peripheral wall 16. The number and the The arrangement of the compartments 24 are chosen so as to have all the same area and the same perforation rate, as well as a maximum size equal to approximately 300 mm. The primary distributors 13 and secondary 14 are directly superimposed, that is to say that each wall 16 or 19 of one of these is in the vertical extension of the corresponding wall of the other. The upper edge of at least some of the walls of the secondary distributor is fixed to the bottom 15 of the primary distributor, such that they form a monobloc assembly. The distributor IB is identical to the distributor IA, but in the primary distributor 13 the pairs of parallel walls 19 bordering adjacent gutters 20 are joined at their upper end by double-ceilings 26 and comprise a horizontal row of openings 27 just below of these ceilings, as indicated in mixed traces in Figure 2. In service, the liquid descending in column 2 is in heat and material exchange ratio with the gaseous oxygen obtained by liquid oxygen heating, collected in the bucket of the medium pressure column. This gas is enriched progressively in nitrogen when ascending to column 2. The gaseous circulations have not been represented in Figure 1 for clarity. However, it is understood that the ascending gas passes through the distributors IA and IB without difficulty through the lights 17 and the openings 27, as is schematized with arrows in Figure 2. When the structure 3 is in the sea, the axis of the column 2 oscillates around its • normally vertical position. The terms "horizontal" and "vertical" previously used to describe the distributor 1, should be understood for this median position of the column, but, when it is inclined, the layer of tubes 11, the bottoms 14, the walls 16 and 19 and partitions 23 and 25 are inclined at the same angle. Thanks to the pressurization of the liquid in the secondary distributor in multiple compartments 24 of small size, the difference in level between the holes 18 of each compartment 24 remains very low in all positions of the X-X axis., whose maximum inclination is typically between 5 and 10 °. As a result, the height of liquid that the corona varies little from one hole to the other. It is also observed that at all times the strongly-fed orifices are adjacent to the poorly fed orifices of an adjacent compartment, so that both flow rates are easily compensated in the same region of the upper package 6 of the immediately underlying distillation section. The influence of the inclination on the uniformity of the distribution of the liquid is further reduced, on the one hand by the balanced feeding of the compartments 24 by the four primary compartments 22, whose areas are four times smaller than that of the column 2, and by another side because, by varying the inclination periodically, with a relatively short period generally of the order of 20 s, the average level in each compartment 24 does not have time to vary considerably. Also, the proximity of the tubes 11 and the holes 111 ensures a balanced feeding of the compartments 22 despite the inclination of the X-X axis. This result could also be obtained, in a variant, by means of four tubes starting from four adjacent points of the bottom of the separator 9 and each of an orifice 111 that leads to lead from a respective compartment 22. In total, a distribution of the liquid with a satisfactory uniformity is obtained in the entire section of the column.

If desired, each compartment 22 of liquid remixing means can be equipped, for example inclined walls descending from the wall 16, as already known. The application WO-A-90/10 497 describes, inter alia, a coating analogous to the aforementioned corrugated-crimped coatings, but perforated differently. The term "corrugated-crimp coating" used herein also comprises such a coating, as well as any analogous coating. It is noted that with regard to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which the isina refers. Since the merits of the merger as above, the property contained in the following is claimed as property:

Claims (11)

R E I V I N D I C A C I O N S

1. Liquid distributor for distillation column, characterized in that it comprises; in its use position: - a primary distributor comprising liquid distribution openings and delimiting NI first compartments, with NI > 2; - Means of liquid balanced feeding of each of the first compartments; and - a secondary distributor arranged under the primary distributor and comprising a basin with perforated perforated bottom which occupies almost the entire section of the distillation column, this basin being subdivided by partitions • in N2 second perforated bottom compartments, with N2 > NEITHER; being the ratio of the area of each second compartment to the sum of the sections of the openings of the primary distributor that feed it almost constant from a second compartment to another.

Distributor according to claim 1, characterized in that all the second compartments have almost the same area and the same perforation rate.

3. Distributor according to claim 1 or 2, characterized in that the number Ni is less than 10 and the number N2 of the order of several tens.

Dispenser according to any one of claims 1 to 3, characterized in that the primary distributor comprises a primary cuvette whose perforated bottom has the same configuration as that of the secondary cuvette and is superimposed on this last one.

Dispenser according to any one of claims 1 to 4, characterized in that said feeding means comprise a phase separator and a supply conduit connected upwards with the lower part of this separator and downwards with tubes that are perforated to lead of each of the first compartments, the ratio of the area of a first compartment to the sum of the sections of the corresponding perforations of the tubes being constant from one first compartment to the other.

Distributor according to claim 5, characterized in that the tubes are punctured at adjacent points of the supply conduit and contain holes adjacent to the central axis (X-X) of the distributor.

Dispenser according to any of claims 1 to 4, characterized in that said feeding means contain a phase separator and perforated tubes connected to adjacent points of the lower part of the separator.

8. Distillation column, characterized in that it comprises a liquid distributor according to any of claims 1 to 7.

9. Distillation column, characterized in that said liquid distributor is arranged in a first level of the column, specifically in the part above, and in that the column comprises, on at least one second level, a second liquid distributor according to any of claims 1 to 7.

Distillation column according to claim 9, characterized in that The primary distributor of the second liquid distributor occupies almost the entire section of the column and is directly fed by the liquid coming from the distillation section that crowns it.

11. Distillation column according to any of claims 8 to 10, characterized in that it is shipped on a floating structure such as an oil platform in the sea or a vessel.