Untitled record

full description

hidden invention

The present invention delves into the field of gas and liquid distribution in fixed bed type catalytic reactors operating in a co-current gas/liquid downflow mode.

5 The main is the hydrotreatment of gas oil or other oil stocks, and generally any processes using one or more reactors operating in a gas/liquid flow method.

.downflow)

The vast majority of existing distributors consist of a plate with distribution elements such as those described, for example, in the article:

Gas-liquid distributors for trickle bed reactors: A Review”, by RN Maiti “ 10

6182-6464, 46, 2007and KDP Nigam, IndEngChem Res

These chimneys (chimneys) may be of various types and are placed in various shapes on the plate, as described in the patents:

American No. 0127160(a)/1/2002, American No. 6093373, American No.

15th 01972451(A) 1/ 2004, American No. 0241467(A) 1/ 2007, British No. 721247,

American No. 658738, American No. 145610/2007 and American No. 594216.

Previous art distribution plates with perforated chimneys operate on the basis of gravitational flow. The liquid is distributed by passing the liquid through holes generally distributed parallel to the side walls of the chimneys.

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The gas is distributed through the hole at the top of the chimney. However, a lack of horizontal parallelism may arise in this salt due to the bending of the salt due to its weight or the transformation of the mentioned salt with respect to the horizontal plane when it is installed.

5 In the presence of a deficiency in the horizontal parallel of the plate, the height of the retained fluid is not the same above the distributor plate, and this results in an imbalance of the distribution of the fluid over the subsequent catalytic bottom, especially when the fluid level is close to the row of holes.

Prior art distributor plates with 'bell-cap' type chimneys are also sensitive to the lack of horizontality of the plate. The bell-cap chimney consists of a central cylinder crowned with a bell-cap provided With many cracks Gas and liquid pass through the cracks and through the bottom of the bell cap, and also in an empty space between the bell cap and the master cylinder. Various other forms of bell hood flue exist, such as “vapour-lift” flues (US Patent No. 145610/2007, US No. 5942162), but the principle of operation remains the same.

The operation of the chimneys of the bell hood is based on the withdrawal of liquid by gas through the gap between the bell cap and the cylinder. However, in the presence of a lack of horizontal parallelism in the salt, the height of the liquid bulkhead 15 becomes asymmetric over the distribution plate. Thus, the distance between the opening of the surfaces of the gases between two parallel chimneys becomes relatively large and the fluid withdrawal does not become homogeneous between the chimneys, which causes a fundamentally wrong distribution of issues. The main aggravating factors of this phenomenon are the opening at the bottom of the bell cover and the large number of cracks.

If this is not controlled, this misdistribution fundamentally reduces the performance of the reactor.

20 General description of the invention

The impeller is from a distribution plate placed before a catalytic bed in the

Combined flow reactor

of gas and liquid is the distribution of the mixture of the two phases of

Gas

The liquid is as homogeneous as possible above the catalytic bottom located beyond. At the exit of the chimneys of El Mouh, it forms

Generally, the flow of a two-phase mixture is a concentrated jet.

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Brief explanation of drawings

Figures 1a and 1b represent a schematic view of the distributor plate from the invention, showing the outer cylinder 2 and the inner cylinder 1 robustness forming the distribution element where the outer cylinder 2 rises by 3h relative to the level of the distributor plate base.

5 Figure 2 represents a plot of the inequality of the fluid imbalance coefficient (defined below in the description) as a function

(function of the surface velocity of the liquid

(Vsl), which means that the invention plate can be compared to a smoked instrument from earlier art.

Figure 3 represents a graph of the variance in the fluid imbalance coefficient (defined below in the description) as a function of the surface motion velocity of the problems (Vsl), which means that the invention plate can be compared to a chimney device 10 from prior art commonly known as a 'chimney-bell-cover' device cap chimney(".

Description:

The purpose of the invention is to improve the quality of the distribution of the distribution panels of the previous art by providing them with distribution elements with less sensitivity to lack of horizontal parallel than the perforated stacks and chimneys of the bell cover of the previous art, as well as with better flexibility in operation.

15th The distributor plate of the present invention consists of many elements

Distribution elements are evenly distributed over the aforementioned source in a rectangular, square or triangular pattern.

The distribution element is composed of

from

The distributor plate of the current invention is made of two cylindrical tubes

The cylindrical tubes are approximately concentric and acoustic, and the outer cylindrical tube provides one

20 One or more slots for the passage of gas and liquid.

The two concentrator tubes are prepared to define an annular mixing zone for gas and liquid and to allow the resulting gas/liquid mixture to be reintroduced at different points of the reactor section in as homogeneous manner as possible.

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The outer cylindrical tube rises in relation to the level of the salt, and this means the possibility of determining the height of 3h, to form a protection for the slit or cracks of the entry of the liquid against a possible blockage due to impurities that may be present in the liquid feeding, especially when the feeding of the liquid is Heavy hydrocarbon The height of the outer cylinder also means that the blockage can be reduced at the slug level, with the advantage of better fluid distribution over the distributor plate.

In contrast to the operation of the plates of the previous art, the operation of the distribution elements of the invention depends mainly on drawing the fluid into the high part of the annular space separating the two coaxial cylinders in the axle under the influence of the gas phase flow. On the side wall, this ensures better control of the dry slit (10 section open for gas flow) and thus makes the invention plate less sensitive to lack of horizontal alignment.

One advantage of the present invention is that the height of the dry slot is always sufficient to allow homogeneous admission of gases in the annular (zone) and in fact allow parallel intake of fluids between the stacks.

In practice, the use of this new distribution element means that, on average, over a large fluid range of 15, the sensitivity can be reduced for a wave's lack of horizontal alignment.

More specifically, the present invention may be defined as a diffuser plate for a gas-liquid flow

Topic (gas-liquid flow in downflow co-current mode) in a co-current mode

At various levels of a reactor which may include several catalytic beds, in order to ensure a homogeneous distribution of the resulting gas-liquid mixture over a catalytic bed located beyond said sludge, 20 said slater is provided with distribution elements uniformly distributed over the surface of the slater in a square or patterned pattern. octagonal.

The distribution element consists of two cylinders united in the intrinsic axis (substantially coaxial cylinders) called the inner cylinder (1 (inner cylinder with a diameter of 1d and a height).

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1h, the outer cylinder (2) with a diameter of 2d and a height of 2h, the lower horizontal surface (5) dividing the two cylinders darkened.

The lateral wall of the outer cylinder 2 provides at least a vertical slit

One substantially vertical slot 4 for gas and liquid entry into the zone

5 In the annular zone (3), the gas-liquid mixture in the annular zone 3 is drawn as an upward flowing current, then passes into the inner cylinder 1 through the upper opening (6) from it and descends into the inner cylinder 1, then exits through the opening (7) located at lower end of the inner cylinder 1.

According to the invention, the darkened horizontal surface (5 closed horizontal surface) is located from

10 The distribution element is above the base of the distributor plate at a height of 3h in the range 10 to 100 mm, preferably in the range 20 to 60 mm.

The number of bed slits should be 4 with a height of 4h in the range 1 to 3, and more preferably in the range 1 to 2.

Preferably the degree of inclination between the distribution elements according to a square or triangular pattern in the range 15 100 to 300 mm, more preferably in the range 100 to 200 mm.

The quantitative height of the distribution elements, computed from the base of the distributor plate, is in the range 100 to 500 mm, preferably in the range 200 to 400 mm.

The main dimensions of the distribution elements are symbolized as follows:

Outer cylinder height: 2h;

20 Outer cylinder diameter: 2d;

Inner cylinder height: 1h;

inner cylinder diameter: 1d;

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Gas-liquid mixture incision height: 4h;

Width of the gas-liquid mixture entry slit: ef;

Height of the outer cylinder relative to the plane of the base of the stirrer, 3h;

The values ​​of these main dimensions are in the following range:

5 2h is in the range 100 to 500 mm, preferably in the range 200 to 400 mm;

2d is in the range 15 to 300 mm, preferably in the range 50 to 200 mm;

1h is in the range 100 to 500 mm, preferably in the range 200 to 400 mm;

1d is in the range 10 to 100 mm, preferably in the range of 25 to 75 mm;

4h is in the range 10 to 500 mm, preferably in the range 100 to 300 mm;

10 ef is in the range 1 to 5 mm, preferably in the range 1 to 3 mm;

3h is in the range 10 to 100 mm, preferably in the range 20 to 60 mm.

The gas and liquid inlet slits may have a wide variety of shapes, the simplest and preferred shape is a rectangle (ef, 4h), or a triangular shape, also characterized by the dimensions 4h and ef, and the top of the triangle is directed up or down.

15th The distributor plate of the current invention may in some cases have a certain gradation between the axes

The two cylinders, the inner and the outer, form its structure. The expression “significantly” or “approximately” in a common axis should be interpreted in its broad sense, given that the distance between the two axes may be in the range of zero to (2d - 2d).

.4)/1d

The diffuser plate of the present invention may be completed by a set of conical chars

20 (conical deflectors), each deflector is placed below a distribution element, and the wide section is

Cone waves down.

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In general, any type of graph known to skill in the art may be used in the context of the present invention.

5 The diffuser panel of the present invention may also be completed by a set of screen elements placed after the salt with a space in the range 20 to 300 mm, preferably in the range 50 to 150 mm of the aforementioned salt, and the various barrier elements are also placed at different levels. If present, these edges or barrier elements form an integral part of the invention plate.

The distributor plate of the present invention is mainly used in reactors for hydrotreatment, hydrogenation or oxidation reactors 10 for oil rations with a number of carbon atoms from 4 to 30, preferably 8 to 20.

In general, the distributor plate of the invention is used in reactors that use a combined current flowing from

Gas and liquid in the “trickle bed” style, meaning with the speed of surface movement of problems

In the range 0.1 to 1.5 cm/sec. The invention can be defined as a distributed panel prepared for streams

It is a gas-liquid phase with a flowing combined stream method. This salt is intended to be installed in reactors used

15th This type of two-phase current, more specifically by the "trickle bed" method, which

Determines

that is a stream

Where the continuous phase is the gas phase and the discontinuous phase is the liquid phase,

The fluid exists in the form of nearly regular droplets, with the velocity of the fluid's surface movement in the range of 0.1 to

1.5 cm/sec.

The dispensing elements are evenly distributed over the dispenser board in a pattern that may be rectangular, square or triangular.

20 The distribution element consists of two roughly coaxial cylinders, the inner cylinder with a diameter of

d1 and the outer cylinder with a diameter of d2.

The two coaxial cylinders essentially define an annular zone (3) where

Gas and liquid move in a blind flow manner. In fact, gas and liquid enter the 3 . ileal zone

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Through one or more longitudinal slot 4 Penetrating the length of the outer cylinder wall

.2 (outer cylinder)

The lower section of the slit generally allows liquid to enter, and the upper section of the slit generally allows gas. Thus, it is essential that this upper part of the slit, called the slit, be

5 "dry", sufficient to let the gas in at the desired flow rate. One of the advantages of the distribution elements of the present invention is that they have a low sensitivity to any decrease in horizontal parallel due to the height of the dry slit which is always sufficient to allow gas to enter the annular region 3.

The outer cylinder 2 is not bolted to the base of the stirrer and stops at height 3 h. The longitudinal slit 4 starts at the height h3 mentioned above the platen and extends to the height h3+h4.

10 The horizontal surface (5 (horizontal surface) separating the outer cylinder is 2

The inner cylinder 1 is closed.

The number of 4 longitudinal slits is limited to 2 or 3 for each distribution element. These various characteristics mean that the function of the distribution elements is substantially improved, especially in the presence of a lack of horizontal parallel. The fact that the number of cracks is low and the bottom of the distribution element is darkened means that

15th The height of the liquid trap is better controlled, so that we ensure a sufficient dry slit height, so that in the case of lack of horizontal parallelism, the distance between the open surfaces of the gases between the two distribution elements with a certain contrast is small.

In contrast to US Patents No. 2007/145610 and 5941261, the system does not need to determine the two-phase current in the section between the center tubes where the current is of a type

20 Lifting the gas, unlike gas and liquid at the slit, and forms a two-phase emulsion that occupies each annular void defined by the two essentially concentric cylinders.

the sinners

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The two comparative examples below depict the advantages of the distribution system of the present invention in comparison with the tools of earlier art.

Example 1 compares the distribution efficiency of a spreader of the invention with a standard spreader panel with flues.

When the inspiration (from a previous art or from an invention) is subject to a decrease in horizontal parallel by an amount

5 1 = ΔH cm, the sensitivity of the decrease in the horizontal parallel of the wave is quantified by defining the non-parallel function

The fluid balance is as follows:

IqL(%) = QL.chimney1 - QL.chimney2 x 100

(QL.chimney1 + QL.chimney2)/2

where:

10 QL.chimney1,2 is the flow rate of the volume of fluid leaving the two chimneys with function 1 and 2 of

Molars are located at a difference in height corresponding to a decrease in the horizontal parallel by ΔH = 1 cm.

A low value of the fluid imbalance function indicates a low sensitivity to lack of horizontal parallelism. In contrast, a high value for IqL indicates a significant imbalance in the distribution.

The standard stirrer is provided with perforated stacks for the passage of the distributed liquid through several 15 rows.

The main characteristics of standard chimneys are as follows:

triangular slope of 200 mm between chimneys;

rows of perforations at a height of 150/100/50 mm from the base of the spur;

Chimney height: 250 mm;

20 Chimney diameter: 50 mm;

Number and size of holes per row: 3 holes by 7 mm.

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The shape of the flue perforation is determined for a range of motion velocities of issues in the range of 0.2 to 1.3 cm/sec and for a gas movement velocity of 15 cm/sec.

The distribution elements of the invention have the characteristics specified in Table 1 below.

Function 1 refers to the inner cylinder and function 2 refers to the outer cylinder.

5 Table 1

<tr><td><p>150</p></td><td><p>H4 (mm)</p></td></tr><tr><td><p>25</p></td><td><p>H5 (mm)</p></td></tr><tr><td><p>320</p></td><td><p>H2 (mm)</p></td></tr><tr><td><p>40</p></td><td><p>H3 (mm)</p></td></tr><tr><td><p>50</p></td><td><p>d1 (mm)</p></td></tr><tr><td><p>110</p></td><td><p>d2 (mm)</p></td></tr><tr><td><p>2</p></td><td><p>ef (mm)</p></td></tr><tr><td><p>1</p></td><td><p>number of incisions</p></td></tr>

Figure 2 represents the variance of the fluid imbalance function IqL (top L coordinate) as a function of

Surface motion velocity of VSL problems (with x-coordinate length) for prior art (solid line curve) and invention palette (dashed line curve).

To suggest from prior art, the fluid imbalance varies between 5: and 40: across the range

10 The full VSL in question (from 0.1 to 1.3 cm/sec) with peaks corresponding to the VSL that necessitates the opening or obstruction of the hole.

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Thus, there is the effect of large defects on the peaks connected with discontinuities in the holes for the passage of gas and liquid.

In contrast, the tablet shows stable performance with an approximately 13:IqL fluid imbalance function across the full functional range of VSL.

5 This example shows the possibility of using the invention tool to obtain a significant increase in flexibility

and distribution efficiency with a lack of horizontal parallelism.

Example 2 compares the efficiency of the wave distribution of the invention with that of a flue-mounted fan with a bell-hood according to the previous model, in order to decrease the horizontal parallel by ΔH = 1 cm.

Secondly, the efficiency of the distribution is quantified by means of the fluid imbalance function IqL; Speed ​​varies

10 The kinetics of the liquid surface is 0.1 to 1.3 cm/sec.

The characteristics of a chimney slab with a bell hood are mentioned in Table 2 below.

Table 2

<tr><td><p>150</p></td><td><p>Bell Cover Height (mm)</p></td></tr><tr><td><p>40</p></td><td><p>Height of the bell hood relative to the level of the wave base (mm)</p></td></tr><tr><td><p>65</p></td><td><p>Gas-liquid mixture incision height (mm)</p></td></tr><tr><td><p>50</p></td><td><p>Inner cylinder diameter (mm)</p></td></tr><tr><td><p>100</p></td><td><p>Bell cap diameter (mm)</p></td></tr><tr><td><p>22</p></td><td><p>Gas-liquid inlet slot width (mm)</p></td></tr><tr><td><p>3</p></td><td><p>number of incisions</p></td></tr>

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In Table 3 below, the characteristics of the waveform equipped with the distributing elements are specified according to the invention.

Second, function 1 refers to the inner cylinder, function 2 refers to the outer cylinder.

Table 3

<tr><td><p>150</p></td><td><p>H4 (mm)</p></td></tr><tr><td><p>25</p></td><td><p>H5 (mm)</p></td></tr><tr><td><p>320</p></td><td><p>H2 (mm)</p></td></tr><tr><td><p>40</p></td><td><p>H3 (mm)</p></td></tr><tr><td><p>50</p></td><td><p>d1 (mm)</p></td></tr><tr><td><p>110</p></td><td><p>d2 (mm)</p></td></tr><tr><td><p>2</p></td><td><p>ef (mm)</p></td></tr><tr><td><p>1</p></td><td><p>number of incisions</p></td></tr>

Figure 3 shows the variance in the fluid imbalance function IqL as a function of the VSL surface movement velocity for the two inductors.

The results show a high sensitivity to the lack of horizontal parallelism for “bell-hood smoked” panels (steel line curve).

In fact, the degree of misdistribution is more than 100: across the entire career range of

.VSL

10 On the other hand, the invention plate was less sensitive to a deficiency located on the horizontal parallel, which is a function of

Fluid imbalance across the VSL range is practically constant around a value of 13: (dashed line curve).

The two examples clearly demonstrate the advantage of the current invention, the latter allowing a significant reduction in the effect of deficiency

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Horizontal paralleling during distribution board installation, over a range of fluid surface motion velocity from 0.1 to

<p>1.3 cm/sec, i.e. against the “low-flowing bottom” method appropriate to the atmosphere of the invention plate.</p>

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