Apparatus and process for spraying liquids and producing very fine mist

Abstract

An apparatus and process for spraying liquids and producing very fine mist with the apparatus, the apparatus including: a needle injector that includes a capillary line (1) and an outer tube (8); a liquid supply (5); and a gas supply (4), where: the capillary line (1) is arranged in the interior space of the outer tube (2); the internal diameter of the capillary line in the needle injector is in the range of 2-1000 m; the capillary line is in active communication with a gas supply (4); and the outer tube (2) is in active communication with a liquid supply (5).

Claims

1. An apparatus for spraying liquids, comprising: a needle injector; a liquid supply; and a gas supply, wherein: the needle injector comprises a capillary line and an outer tube; the internal diameter of the capillary line of the needle injector is in the range of 2-400 m; the capillary line is coaxially arranged in the interior space of the respective outer tube; the capillary line is in active communication with the gas supply; the outer tube is in active communication with the liquid supply; and a tip of the needle injector is configured such the capillary line is longer than the outer tube.

2. The apparatus of claim 1, wherein the apparatus is joined to a housing.

3. The apparatus of claim 1, wherein the tip of the needle injector is configured such that a length difference between the capillary line and the outer tube is in the range of 1 to 10 mm.

4. The apparatus of claim 1, wherein the apparatus is configured for operation in conjunction with a catalyst testing setup for examining FCC catalysts and/or an aging or impregnation unit for FCC catalysts.

5. A process for spraying liquids with the apparatus of claim 1, wherein the process comprises: (i) controlled introduction of a gas via the gas supply into the capillary line; (ii) controlled introduction of a liquid via the liquid supply into the interior space of the outer tube; and (iii) contacting of the liquid conveyed through the outer tube with the gas conveyed through the capillary line at a tip of the apparatus.

6. The process of claim 5, wherein the liquid which is conveyed through the outer tube has a volume flow in the range of 0.1-10 ml/min, and/or the gas which is conveyed through the capillary line has a volume flow in the range of 10-300 ml/min.

7. The process of claim 5, wherein the apparatus is joined to a housing, and wherein the housing, the gas supply and/or the liquid supply are heated, with the temperature of the gas supply being in the range of 50-300 C.; the temperature of the liquid supply being in the range from 50-300 C.; and the temperature of the housing being in the range of 80-700 C.

8. The process of claim 5, comprising spraying a heavy oil.

9. The process of claim 5, comprising spraying an oil, wherein the oil is introduced in pulses or continuously and the pulses have a duration in the range of 1-400 seconds.

10. The process of claim 5, wherein the needle injector comprising the capillary line and the outer tube is arranged vertically.

11. The process of claim 5, wherein a very fine mist is produced by the process, having a mass flow ratio of gas to liquid of <0.1.

12. The process for of claim 5, wherein the process is controlled by a PC.

13. The apparatus of claim 1, wherein the tip of the needle injector does not comprise an internal mixing chamber.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1: Schematically shows the apparatus of the invention for spraying liquids having a capillary line (1) and outer tube (2), with the apparatus being arranged in a tubular housing (3). The tubular housing is surrounded by a heating device (6).

(2) FIG. 2.a: Schematically shows the cross section through the injector of the apparatus of the invention, with the injector having a capillary line (1) and an outer tube (2).

(3) FIG. 2.b: Schematically shows the cross section through the injector of the apparatus of the invention, with the injector having two different capillary lines (1) and (1) and also an outer tube (2).

(4) FIG. 2.c: Schematically shows the cross sections of variously configured capillary lines having a hexagonal shape (1), a square shape (1) and a triangular shape (1).

(5) FIG. 3: Shows a photograph of the injector tip (8) in the operating state, with a colored solution being sprayed by means of the apparatus of the invention. The spray cone has an opening angle of 14. Individual droplets cannot be resolved optically.

(6) FIG. 4: Schematically shows the apparatus of the invention for spraying liquids in an arrangement having a plurality of apparatuses. In the present case, the apparatuses for spraying liquid are used in a setup for impregnating catalysts, with the setup having three apparatuses (d1, d2, d3) at the top and two lateral apparatuses (d4, d5).

DETAILED DESCRIPTION OF THE INVENTION

(7) In a preferred embodiment, the apparatus of the invention is joined to a housing, preferably a tubular housing (3), with preference being given to the housing being in active communication with a heating device (6).

(8) The tip (8) of the apparatus is preferably configured in such a way that the length difference between the capillary line (1) and the outer tube (2) is in the range of 0-10 mm, with the length difference preferably being in the range of 1-5 mm and the capillary line (1) preferably being longer than the outer tube (2).

(9) In the apparatus of the invention, the tip (8) of the needle injector does not have an internal mixing chamber. The mixture of liquid and gas thus goes directly into the outer region of the needle injector without entering a mixing chamber. The absence of a mixing chamber is advantageous since the configuration of the apparatus without mixing chamber is associated with a smaller engineering outlay than an injection apparatus equipped with a mixing chamber. In addition, the apparatus of the invention is also very robust.

(10) In addition, preference is given to the apparatus being operated in conjunction with a catalyst testing setup for examining FCC catalysts and/or an aging or impregnation unit for FCC catalysts.

(11) In this preferred embodiment as catalyst testing setup or as impregnation apparatus, the apparatus according to the invention is connected to a tubular housing (3).

(12) The invention also provides a process for spraying liquids, which is carried out by means of the apparatus of the invention, wherein the process comprises the following steps: (i) controlled introduction of a gas by means of the gas supply (4) into a capillary line (1), (ii) controlled introduction of a liquid by means of the liquid supply into the interior space of an outer tube (8), (iii) contacting of the liquid conveyed through the outer tube (8) with the gas conveyed through the capillary line (1) at the tip (8) of the apparatus.

(13) Furthermore, in the process for spraying liquids, the liquid which is conveyed through the outer tube (2) has a volume flow in the range of 0.1-500 ml/min, preferably in the range of 0.5-250 ml/min, and/or the gas which is conveyed through the capillary line (1) has a volume flow in the range of 10-10 000 ml/min, preferably in the range of 20-2000 ml/min.

(14) In a preferred embodiment, the supply or introduction of gases or liquids is carried out with these being heated. For the heating, regions of the housing, the gas supply and/or the liquid supply are heated, with the temperature of the gas supply being in the range of 50-300 C., preferably in the range of 100-250 C.; the temperature of the liquid supply being in the range from 50 to 300 C., preferably in the range from 100-250 C.; and the temperature of the housing (3) being in the range of 80-700 C., preferably in the range of 100-650 C., more preferably in the range of 150-550 C.

(15) In the process of the invention, the atomization of the liquid, preferably the oil, is effected without a nozzle. The needle injector preferably has a tubular or stump-like tip as shown in FIG. 1. The needle injector will hereinafter also be referred to as coaxial needle injector. In a preferred embodiment, heavy oils such as VGO, HVGO are sprayed by means of the process of the invention.

(16) The longitudinal axis of the coaxial needle injector comprising at least the capillary line (1) and the outer tube (2) is preferably arranged vertically.

(17) In a preferred embodiment, the process of the invention is carried out using an apparatus in which a plurality of apparatuses (d1, d2, d3, . . . ) for the injection of liquids are installed.

(18) In the process of the invention, the gas is conveyed with a high linear velocity through the inner tube and at the exit point has a linear velocity of >170 m/s (i.e. greater than or equal to 170 m/s) given by the ratio of volume flow to cross-sectional area of the inner tube and is greater than mach 0.5, preferably greater than mach 0.7, in particular greater than mach 1.0. The mach number is a mathematical parameter which is derived from the volume flow through the cross-sectional area at the upper end of the capillary (i.e. the exit area).

(19) The high linear velocity of the gas is an essential element of the process of the invention. The high linear velocity can be achieved by the inner tube being formed by a capillary line. The capillary also has to be controlled by means of an appropriate admission pressure in order to convey a sufficient amount of gas through the capillary. One parameter of the process of the invention is given by the ratio of the volume flow of the gas stream to the volume flow of the liquid, with a preferred gas volume flow having a volume flow of 80 ml/min and a preferred liquid volume flow being 5 ml/min. The ratio of gas volume flow to liquid volume flow is thus 16, the ratio of gas volume flow to liquid volume flow preferably being in the range of 500-1, more preferably in the range of 10-200, particularly preferably in the range of 12-100.

(20) It can be seen from the technical parameters that, in a preferred embodiment of the process of the invention, the very fine mists produced by means of the process have a very low mass flow ratio of gas to liquid. The mass flow ratio of gas to liquid is preferably <0.1, more preferably the mass flow rate of gas to liquid is <0.04. The mass flow is here reported (by way of example) in kg/h, with the units in the reported mass flow ratio being abbreviated and becoming redundant. This process aspect or parameter produces a significant difference compared to the processes described in the prior art. Another advantage here is that the very fine mists produced have low flows and very small amounts of gases and of liquids are consumed.

(21) It is also possible to use alternative embodiments of capillaries. These consist, for example, of thin tubes which are provided at the ends with orifice plates and micropins. The use of capillaries is, however, particularly preferred. Capillaries having various diameters and lengths can be purchased. In particular, capillaries having small internal diameters are also available. In the context of the invention, high gas exit velocities are of great importance and these can be achieved particularly readily by means of capillaries. For the purposes of the present invention, high gas exit velocities are, in particular, exit velocities which are greater than or equal to mach 1.5, preferably greater than or equal to mach 2.0. (The mach number is determined as indicated above.)

(22) It should be mentioned that in the process of the invention, the amount of gas which is conveyed through the inner tube is, on a mass basis, 18 times smaller than the amount of gas used in coaxial two-phase atomizers as are known in the prior art or are commercially available.

(23) As regards the volume flow, this means that the gas conveyed through the inner tube has a volume which is a factor of 16 smaller than in the case of the two-phase atomizers known in the prior art. In relation to the process of the invention, it can also be said that an important characteristic of the invention is that a spray mist which firstly has only a low flow rate and secondly contains an extremely fine dispersion of liquid droplets is produced.

(24) The combination of the apparatus of the invention and the process of the invention for the injection of oils results, in connection with use in conjunction with agitated catalyst beds, in synergy effects, by means of which particularly homogeneous wetting of the catalyst particles which cannot be achieved by means of the injectors known from the prior art is made possible. Furthermore, the use in conjunction with dynamically agitated catalyst beds in downcomer tubes or in riser reactors is also preferred since in this case improved control of injection is of critical interest for the quality of the experimental test data.

(25) With regard to a preferred embodiment of the liquid supply (5), it can be said that this comprises a pump or a syringe and also a stock vessel with liquid. Particular preference is given to a liquid supply (5) which has a pump. The pump is more preferably a high-pressure pump (for example an HPLC pump).

(26) In a preferred embodiment, the gas supply (4) comprises a gas supply network and a pressure regulator.

(27) In addition, preference is given to an embodiment in which the liquid supply (5) and/or the gas supply (4) is connected to a process control system (PCS). The parameters of the process can be controlled or regulated by means of the process control system. The parameters include the duration of the introduction of the spray mist by means of the apparatus of the invention, the flow rate of the gas stream and the flow rate of the liquid to be metered in. in a preferred embodiment, introduction of the spray mist can be carried out continuously. In another embodiment, which is likewise preferred, the introduction can be carried out in the form of metered pulses. Furthermore, continuous introduction and introduction in pulses can be carried out alternately.

(28) A preferred field of use of the invention relates to use of the apparatus for the injection of oils in connection with laboratory catalyst testing setups. Particular preference is given to laboratory catalyst testing setups for testing FCC catalysts; here, the use in connection with laboratory catalyst testing setups which have an agitated catalyst bed is particularly preferred. Particular preference is also given to riser reactors or downcomer tube reactors.

(29) A further preferred field of use of the apparatus of the invention and the process of the invention is in connection with apparatuses for the controlled deactivation of FCC catalysts, in which the catalysts are impregnated with oils or metal salt solutions under controlled conditions in fluidized beds in heated reaction tubes. These are known as aging units for catalysts. As metal salt solutions, it is possible to use, for example, vanadium salt solutions or nickel salt solutions. As an alternative, it is also possible to spray the catalysts with solutions in which the metals are present in the form of metal-organic compounds. Wetting of the catalysts under controlled conditions is thus possible. The organic compounds are removed by burning-off in a thermal treatment step. Here, it is possible to use temperatures in the range of 500-700 C.

(30) Another advantage of the apparatus of the invention is that the formation of carbonaceous material at the end of the liquid outlet is efficiently suppressed. The formation of carbonaceous material in the injection of oils into reaction spaces which are operated at high temperatures above 400 C. represents a great technical problem since oil injection is either interfered with or completely blocked as a result. Blocking of the oil injection leads to the study having to be stopped. The apparatus has to be taken apart and cleaned.

(31) Here, it should also be noted that the apparatus of the invention and the process of the invention can have different configurations depending on the field of use, i.e. use in metal impregnation or use in laboratory FCC catalyst testing apparatuses. The reason is that apparatuses for metal impregnation are generally charged with relatively large amounts of catalyst. The individual impregnation tubes have a catalyst charge in the range from 50 to 200 g. It is in such a case frequently necessary to spray a relatively large amount of liquid into the reaction space and onto the catalyst. It is therefore possible for a plurality of injection apparatuses according to the invention to lead into a single reactor. For example, a single reaction tube can be equipped with from two to six apparatuses according to the invention for the injection of oils. The individual apparatuses can, depending on the configuration of the aging apparatus, all spray feed liquid into the impregnation tubes at the same time or be operated individually.

(32) The configuration of the openings is not restricted to a single coaxial or circular arrangement of the capillary line in the interior space and the liquid-conveying line as outer tube. It is also possible for two or more capillary lines to be located in the interior space of the outer line (2) (see FIG. 2.b). The capillary can likewise have different geometric shapes. Apart from a round or elliptical cross-sectional area, it is also possible for the capillary lines to have, for example, a hexagonal shape, a square shape or a triangular shape. Embodiments of these types are shown in FIG. 2.c. The length of the capillary can be from a few millimeters up to a number of meters. The length of the capillary line is preferably in the range of 1-150 cm; preference is also given to a length in the range of 3-100 cm, particularly preferably a length in the range of 3-20 cm. The capillary lines are preferably made of metal, steel, glass, silica, ceramic, plastic. Particularly preferred materials are steel or fused silica.

(33) Another characteristic of the process of the invention is that reagglomeration or coagulation of the atomized liquid droplets is very low.

(34) The process of the invention can be used for the atomization of both low-viscosity liquids and high-viscosity liquids.

(35) It may be mentioned here that the high-viscosity liquids (i.e. liquids having a low flowability) have a significantly better tendency to form droplets than low-viscosity liquids (i.e. liquids having a high flowability). For example, water has a viscosity at 20 C. of 1.001 mPa*s and dodecane has a viscosity of 1.520 mPa*s. In connection with the process of the invention, dodecane thus has a higher tendency to form droplets than water.

(36) Use in the FCC Sector

(37) Preference is given to using the apparatus of the invention and the process of the invention for the injection of oils in combination with catalyst testing setups for testing FCC catalysts. It is particularly advantageous that the process is very easy to control; in FCC tests, precise control of the introduction of feed fluid or the introduction of oil is of great importance, especially the introduction of amounts in the range from 0.1 to 50 g/min, preferably 0.5-10 g/min.

(38) The catalyst has a temperature in the range from 600 C. to 800 C., while the temperature of the feed liquid is in the range of 50 to 300 C., preferably in the range from 100 to 250 C. An upper temperature limit is imposed by thermal cracking of the liquids otherwise occurring, which has an adverse effect on the tests. A particular minimum temperature is necessary, in particular, when the oils have to be liquefied first.

(39) The temperature in the reaction space of the catalyst testing setup is 550 C., with the oil, which is, for example, preheated to 250 C., being injected under controlled conditions into the reaction space. It should be noted that the process of the invention is much better for achieving very homogeneous mixing of the oil droplets and the catalyst particles at this point so that they can react under controlled conditions. The apparatus of the invention and the process of the invention result in the oil being atomized very finely and the atomized oil being able to be brought into intimate contact with the catalyst within a few milliseconds. Here, the oil is also heated, for example in the present case to 550 C. The processes of atomization of the oil and wetting of the catalyst with oil proceed simultaneously.

EXAMPLES

(40) I. To illustrate the apparatus of the invention and the process of the invention, an apparatus corresponding to the schematic depiction shown in FIG. 1 was constructed. To produce the needle injector, a fused silica capillary having an internal diameter of 50 m and a length of 30 cm was introduced into a 1/16 steel tube ( 1/16 external diameter corresponds to an internal diameter of 1.387 mm since the steel tube has a wall thickness of about 0.1 mm) of the same length. A gas supply was connected to an end piece of the fused silica capillary and a liquid supply was connected to an end piece of the steel capillary. The injector equipped with gas supply and liquid supply was positioned vertically in a holder in which the tip of the needle injector was arranged 8 cm above a plate. A rectangular paper strip (4 cm10 cm) was placed on the upper side of the plate underneath the tip of the needle injector. Gas and liquid were conveyed in a controlled manner through the needle injector by means of the gas supply and the liquid supply. The liquid supply was 5 ml/min and the gas supply was 80 ml/min. Spray injections were carried out by means of the apparatus. An intrinsically stable spray mist was produced on exit of the fluids from the ends of the tubes at the tip of the needle injector. The spray mist was collected on the paper strip which had been placed underneath the injector. Ink (a colored aqueous solution) was used as liquid for the spray experiments. In the region underneath the exit opening of the injector needle, a spray mist having a conical shape was observed. No shape changes were to be seen over an observation period of 10 minutes. The spray cone thus had a constant shape. FIG. 3 shows a photo of a spray cone which has an opening angle of 14. Individual droplets are below the optical resolution limit and cannot be seen. The stability of the very fine mist enables a droplet size of from 10 m to 20 m to be concluded.

(41) II. Supporting of an Organic Dye to Produce a Pigment

(42) To illustrate the process of the invention, a pulverulent solid which consisted of an aluminum oxide-comprising support oxide from Alcoa was coated with eosin-comprising ink. The aluminum oxide-comprising support oxide was an FCC catalyst material which had been produced by means of a spray dryer from a spraying suspension, in which the initial components were present. The eosin-comprising red ink was dissolved in acetone, employing a volume ratio of 1:10 (i.e. 1 part of ink to 10 parts of acetone). Eosin is tetrabromofluorescein or the disodium salt of 2,4,5,7-tetrabromo-3,6-dihydroxyspiro[2-benzofuran-3,9-xanthen]-1-one. The concentration of eosin dye (tetrabromofluorescein) in the ink was 1 mol/l. The aluminum oxide-comprising support oxide had an average particle size of 85 m, with the size distribution of the particles being in the range 50-120 m, so that the particles could be brought into the fluidized state by means of a gas stream. The pulverulent aluminum oxide (250 g) was introduced into a heated reaction tube which was provided with an injector according to the invention. The diameter of the reaction tube was 6 mm, and the length was 1 m. The reaction tube was maintained at 80 C. A gas stream was introduced via feed nozzles into the reaction tube, as a result of which the pulverulent aluminum oxide was brought into the fluidized state. While the fluidized aluminum oxide was stored at 80 C. in the feed vessel, spray injection of the eosin solution was carried out for a time of 60 seconds, with the injection being carried out at a flow rate of 10 ml/min. Thus, 10 ml of eosin-acetone solution were injected. In the present case, 250 g per minute of the pulverulent support material were coated under controlled conditions with the dye by means of the apparatus of the invention and the process of the invention. The reaction time or the coating time was carried out in a few milliseconds, with the acetone being separated off directly via the gas phase. (The residence time in the reaction tube was in the range of 2-6 seconds.) The residence time is determined from the gas flow and the proportion of hydrocarbon which is vaporized. The vaporized proportion of hydrocarbon thus increases the volume of the gas stream. In the present case, acetone as solvent for the eosin-comprising dye was vaporized in the reaction tube. The red-coated support was collected downstream of the reaction tube. Analysis of the coated support material indicated that a very uniform and homogeneous distribution of the dye on the individual particles was present.

(43) This process of the invention is, apart from the discontinuous operation presented, suitable for being operated continuously and is therefore particularly suitable for carrying out, for example, supporting on a semiindustrial scale. In the case of continuous operation of the apparatus described in the example, an amount of catalyst of 360 kg/day can be impregnated or coated under the conditions presented here by means of the process of the invention. To carry out the process continuously, the apparatus components for introduction of catalyst, the catalyst receptacle and the reservoir for the impregnation solution had to be appropriately enlarged and adapted. In the apparatus described here, up to 500 kg/day of material can be reacted or treated after appropriate adaptation of the apparatus. In a further embodiment of the apparatus of the invention, the reaction tubes can also be arranged in parallel. In this way, the process can be operated in an even more efficient way since both the high accuracy of the process for coating or impregnation can be utilized and the advantageous configurational possibilities of the apparatus can lead to improved efficiency in operation of the apparatus. Two or more parallel reaction tubes which are provided in conjunction with a joint reservoir for impregnation or coating fluid are advantageous. For example, the apparatus of the invention can, in one embodiment having four reaction tubes arranged in parallel can be used for coating an amount of catalyst of 1.4-2 metric tons per day. Advantages are that the apparatus can have only small dimensions with a reaction tube having a length of one meter and a diameter of 6 mm and the process can be carried out in a short time. At the dimensions of the reaction tube indicated in the example and based on the density of the aluminum oxide of 4 g/cm, from 40 g/min to 250 g/min of material can be coated in this way. In the field of specialty chemicals, daily productions of 1-2 metric tons per day can represent an amount which is of great economic importance.

(44) The embodiments of the apparatus of the invention presented here are not to be interpreted as exhaustive or limiting in any way. In a further embodiment of the apparatus, two or more reaction tubes can be connected in series, with different impregnation or coating solutions being applied to the catalyst material or support material being passed through.

LIST OF REFERENCE NUMERALS

(45) 1, 1, 1capillary line in various configurations

(46) 2outer tube for liquid supply/oil supply

(47) 3housing

(48) 4gas supply

(49) 5liquid supply

(50) 6heating device

(51) 8injector tip

(52) 9contact space, reaction space

(53) 12flow direction

(54) 13joint liquid supply for injectors d1, d2, d3

(55) 14joint gas supply for the injectors d1, d2, d3

(56) 15gas supply for fluidizing gas

(57) 16screen or frit for screening the gas feed lines

(58) d1, d2, d3vertically arranged injectors, top of the setup

(59) d4, d5laterally arranged injectors, longitudinal axis of the injectors has a tilt angle relative to the vertical axis, tilt angle is <40, preferably <30, more preferably <25