JPH0127772B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reactor feed distributor useful in upflow reactors for mixed phase feed streams. This distributor is particularly useful in catalytic coal liquefaction reactors which must be able to accept feeds consisting of gases, liquids and solids.

For many processes, upflow reactors are superior to conventional downflow reactors. This is especially true if the liquid feed also contains solids. Because solids tend to agglomerate,
In the downflow method, it becomes an obstacle. This problem becomes even more pronounced if the feed stream consists of gases as well as solids and liquids.

Upflow reactors are widely used in coal liquefaction systems, such as the liquefaction process disclosed in US Pat. No. 4,083,769 to Hildebrand et al., issued April 8, 1975. As taught in the literature, hydrogen, powdered coal and solvent are preheated and fed into a cracker where the coal is heated to a temperature in the range of 750 to 900㎓ (379 to 482°C) and 3100 to 5000 psi (217 to 350Kg/
cm ² ). The cracker is an empty upflow reactor that provides sufficient residence time for dissolution of powdered coal particles to occur. Solvent, cracked coal, coal residue and hydrogen are removed from the decomposer at a temperature of 25° to 150° (13.9 to
83.3°C) into an upflow catalytic hydrogenation reactor operated at a lower temperature.

Because hydrogen is mixed into the coal slurry prior to the preheating step to avoid coking in the heater, there is little or no control over the degree of mixing of liquid and gas that occurs in the cracker or catalytic reactor. is not carried out. In the case of multiphase flow, gas channeling and/or slugging can occur within these devices. It is undesirable for either of these conditions to exist, since both result in poor contact of the reactants, and slugging can also generate vibrations that can damage the equipment. Furthermore, insufficient mixing of hydrogen can cause reactant coking and equipment fouling under the above process conditions.

It is therefore clear that there is a need for a distributor that accepts a feed stream consisting of liquids, gases and solids and that evenly distributes each phase without blockage or undue abrasion.

US Patent No. 3524731; 4111663; 3146189;
Although a number of mixed phase distributors are known in the art, such as those described in 3195987 and 4187169, there remains a need to solve this problem effectively and economically.

According to the invention there is provided a distributor for a rising reactor of gas-liquid or gas-liquid-solids feed with an inlet in the lower part and an outlet in the upper part. The distributor consists of a plate disposed substantially horizontally within the vessel between the inlet and the outlet. The plate has a plurality of holes extending therethrough and at least one tube extending downwardly, the tube being in open communication with the reaction vessel space below the plate and with the reaction vessel space above the plate. ing. The overall cross-sectional area of the perforations in the plate and the cross-sectional area and length of the tubes are such that, under conditions of feed equilibrium, a gas pocket of a height less than or substantially equal to the length of the tubes is formed in the plate. Designed to occur downwards. Substantially all, i.e. at least 75%, preferably 95%
More feed gas passes through multiple holes in the plate,
Also, substantially all of the feed liquid or feed liquid and solids will pass through the tube, ie at least 75% and preferably more than 95%.

The distributor of the invention is preferably used in a reactor having a fixed or moving bed of particulate catalyst to uniformly distribute gases and liquids or gases, liquids and solids over the catalyst bed. However, distributors can be advantageously used in non-contact vessels, such as decomposers, to bring the hydrogen gas into good contact with the liquids and solids to prevent coking within the vessel.

It is also desirable to provide means for preventing feed gas bubbles from entering directly into the lower end of the tube. If the distributor is used in a catalytic reactor, it should be positioned far enough below the bottom of the catalyst so that any fingering that occurs is completely contained within the liquid space directly below the catalyst. It should be. Although one distributor may be sufficient in some types of reactors, in commercial practice generally multiple distributors will be vertically spaced within the reactor.

Furthermore, the distributor of the invention is particularly suitable for applications in gas quenching or gas withdrawal.

FIG. 1 shows an upflow fixed bed catalytic reactor with one distributor.

FIG. 2 shows an upflow fixed bed catalytic reactor having multiple distributors and suitable for injecting gas between the distributors.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a vertically oriented reaction vessel 10 having a lower feed inlet 20 and an effluent outlet 30 is schematically shown. porous granular catalyst 40
is a lower support grid 5 attached to the inner wall of the tank 10.
0 and may be provided if desired. It is also housed between a catalyst holding net 60 fixed to the inner wall of the tank.

The distributor of the present invention, designated generally by the reference numeral 70, is fixed to the inner wall of the vessel 10 between the inlet 20 and the catalyst support grid 50. The distributor may be secured to the interior wall of the vessel in any convenient or conventional manner, such as by welding or bolting.

The distributor 70 consists of a plate 80 extending over the entire cross-sectional area of the tank 10. This plate has a plurality of perforations or holes 90 passing through it. The hole is 1
Preferably, they are uniformly distributed over the entire cross-sectional area of the plate at a rate of about 20 to 250 or more preferably about 40 to 250 per square meter. An open ended tube 100 is secured in the conventional manner to plate 80 and extends downwardly from a central opening in the plate. Although only one tube is shown in the drawings, it is within the scope of the invention to provide more than one tube if required by feed conditions or reactor dimensions. Approximately 10 or 20 pieces per square meter of board surface area
A book tube will be used.

A cap 110 is provided at the lower end of the tube 100 to prevent gas in the feed from rising directly through the tube. Although cap 110 is shown secured to the end of tube 100 in the conventional manner by extension 120, it may be replaced with an equivalent baffle secured to the wall of the tank. The inlet can be connected to the tube 100 in a manner that solves this problem.
It is also possible to pull it away from the edge. If a cap is used as shown, it is preferably about 20% larger than the diameter of the tube. If multiple distributors are used within the vessel, the upper distributor will not require a cap to prevent significant gas from entering the tube.

In operation, a mixed phase feed stream, preferably consisting of liquids, gases and solids, which will be introduced into the cracker or catalytic reactor of the coal liquefaction unit is pumped or otherwise pumped into the bottom of vessel 10 via inlet 20. introduced in a method.

In accordance with the invention, a gas pocket or vapor space 130 has a height h substantially equal to or less than the length of the tube 100 extending below the plate.
occurs under steady-state conditions and almost all of the gas and vapor components of the feed, i.e. at least
75% passes through hole 90 and almost all of the feed liquids and solids, at least 75%, enters tube 1.
The distributor is designed corresponding to the state of the feed so that the feed passes through 00.

The pressure drop of the steam flow passing through the plurality of holes 90 is
If the pressure drop of the liquid and solid through the tube 100 is balanced by the static differential pressure between the liquid and solid and the gas pocket at height h, plus the static pressure head of the liquid and solid through the tube. For example, it has been confirmed that the necessary flow paths for gas and liquid are secured.

The pressure drop due to the gas flow passing through the perforation plate can be estimated using the orifice equation. If the liquid and solid pressure drops in the tube are negligible, the gas pressure drop is (ρ ₁ − ρg)h, where ρ ₁ is the density of the liquid and solid flow in the tube and ρg is the density of the gas. ) may simply be balanced with a static differential pressure equal to

Therefore, in the present invention, the total cross-sectional area of the number of holes relative to the cross-sectional area of the tube is such that the pressure drop for the gas and the liquid passing through the holes and the tube at a height h is (ρ ₁ −ρg). It is set equal to h.

Preferably, the distributor is designed with a minimum value for h of about 5 to 10 centimeters. More preferably, h should be set to about 10 to 20 centimeters and the design length of the tube should be selected to be about 20 centimeters. These values will allow for significant changes in steam flow rate and therefore gas pocket height. At the design flow rate, these values also ensure that the lower end of the tube is substantially at or below the liquid level, thus preventing significant flow of gas from the tube upon disturbance of the liquid surface. Make it certain.

The upper surface of the horizontal perforated plate is preferably located about 3 to 10 centimeters below the lower grid 50, depending on the growth of the gas bubble.

Although preferred embodiments have been specifically described in connection with a feed to a coal liquefaction unit, the distributor of the present invention may be used in any system having a gas-liquid or gas-solid-liquid feed. Furthermore, when the device is used as a gas quenching device, it is necessary to transfer the gas to the plate 80 for uniform and complete distribution.
All you have to do is inject it below.

FIG. 2 shows a plurality of distributors 70 and a plurality of catalyst beds 4.
0 shows a device according to the invention with 0 and 0; Catalyst bed 40 is drawn to scale to show details of the distributor.
A quench gas, such as a hydrogen-containing cycle gas for a catalytic coal liquefaction process, is charged into the steam space 130 through an inlet 150. Inlet 150 may also be used to vent gas from vapor space 130. If desired, tube 100 may extend into the upper portion of catalyst bed 40, preferably so that the catalyst within the tube is substantially flush with the rest of the catalyst bed. The gas pocket can also contain a portion of the catalyst if desired.

[Brief explanation of drawings]

FIG. 1 shows an upflow fixed bed catalytic reactor with one distributor. FIG. 2 shows an upflow fixed catalytic reactor with multiple distributors.

Claims (1)

[Claims] 1. Feed mixture inlet means in the lower part of the tank;
There is also an effluent mixture outlet means in the upper part of the tank;
a substantially horizontally disposed feed fitted within said vessel, between said inlet means and said outlet means, associated with a gas-liquid mixture or gas-liquid-solids mixture reaction vessel in which the feed is ascending; a material distributor, the plate comprising at least one material distributor extending downwardly from an aperture passing through the plate;
The upper surface of the plate has a number of straight holes extending therethrough, spaced regularly apart from the main tubes and in open communication with the reaction vessel space below the plate; The gas and the liquid are in open communication with the reaction vessel space on the distribution plate, and the total cross-sectional area of the plurality of holes relative to the cross-sectional area of the tubes is such that the gas and the liquid pass through the holes and the tubes at a height h. set such that the pressure drop over the tube is set equal to (ρ ₁ −ρg)h (ρ ₁ = density of said liquid or said liquid and solid, ρg = density of said gas), and said pressure drop is substantially shorter than the length of said tube. Under the plate, gas pockets are such that under equilibrium feeding conditions of gas-liquid or gas-liquid-solid mixtures, a substantial portion of the gas in said mixture fed to said distributor is all of which passes through the plurality of holes, and substantially all of the liquid in the mixture supplied to the distributor passes through the tube. 2. The distributor of claim 1, wherein the reaction vessel further comprises a bed of solid particles located below the effluent outlet means and above the distributor. 3. The distributor of claim 1 further comprising means for preventing direct vertical passage of gas bubbles from the feed mixture inlet means into the tube. 4. The distributor according to item 1, comprising a plurality of vertically spaced distributors within the reaction vessel. 5. The distributor of claim 4, wherein the reaction vessel further comprises at least one bed of solid particles located below the effluent outlet means and above the distributor. 6. The distributor of claim 4, further comprising means for preventing direct vertical passage of gas bubbles from the liquid feed mixture inlet means into the tube. 7 said first, second, third, fourth, fifth or sixth further comprising means for independently introducing the gas of said feed mixture into one or more of the gas pockets;
Distributor as described in section. 8. The distributor of claim 1, 2, 3, 4, 5, 6, or 7, further comprising means for withdrawing gas from one or more of the gas pockets. 9 said first, second, third, fourth, fifth, wherein said horizontally disposed plate is fixedly installed in said reactor;
Distributor according to item 6, 7 or 8.