JPH0420971B2 - - Google Patents

Description

[Detailed description of the invention]

B. Field of Industrial Application The present invention relates to a device for dispersing liquid as droplets in a gas for the purpose of heat transfer or mass transfer. It is particularly applicable for dispersing metallurgical molten phases, such as molten metals, alloys, powders or ash, into droplets in a gas phase for purification or condensation purposes. This dispersed metal can be used as a condensing medium, for example, as molten lead is used to condense zinc vapor from a zinc blast furnace smelting process. B. Conventional technology The smelting of zinc in a blast furnace is based on the paper by Morgan and Utsuzu entitled "Application of Blast Furnace to Zinc Smelting", Metallurgical Review 1971, November 16 (156), page 161-
174). As can be seen from the schematic diagram on page 166 of this paper, the upper part of the furnace shaft is connected via a downward duct to a "lead splash condenser" in which the furnace gases are pumped in several stages. , subjected to a heavy spray of molten lead created by a rotor immersed in a pool of molten lead. A typical prior art rotor head is e.g.
It is shown in British Patent Specification No. 1263165, issued February 9, 1972. C. Problems to be Solved by the Invention It is an object of the present invention to provide an apparatus for dispersing a liquid in the form of droplets in a gas for the purpose of heat transfer or mass transfer. Another object of the present invention is to create a droplet spray with a more intense, constrained and steeper trajectory than hitherto achieved. D. Means for Solving the Problem The present invention is an apparatus for dispersing a liquid, as droplets, in a gas for the purpose of heat transfer or mass transfer, the device being mounted on a substantially vertical axis and In an apparatus in which at least one droplet spray envelope is created by rotation of a rotor head at least partially immersed in the liquid, the rotor head
It consists of a device characterized in that it takes the form of a multi-blade helical impeller with a pitch-to-diameter ratio between 0.6 and 1.7. The rotor head according to the present invention is based on the physical shape of a marine propeller, but the airfoil shape and other physical characteristics have been developed for the application described herein. This liquid is a metallurgical molten phase, e.g. molten metal,
Preferably, it is an alloy, a color, or a color. Preferably, this liquid is a molten metal or alloy that is to be used to condense metal vapors. In the case of zinc vapor, this liquid would be a molten lead/zinc alloy. The impeller preferably has three blades. Preferably, the pitch-to-diameter ratio of the impeller is between 0.6 and 1.3, more preferably between 0.7 and 0.9. The speed of the outer peripheral tip of the impeller is 8 m/m against molten lead.
The speed is preferably within the range of 25 m/s to 25 m/s, and the immersion depth below the static lead surface of the rotor is 100 mm.
Preferably it is between 150mm. Various impeller designs were tested and the best design was found to be a three blade impeller with a pitch to diameter ratio of about 0.75 to 0.85. Typically such impellers produce a spray pattern with an average initial trajectory of about 50° to 60° to the horizontal, compared to a prior art rotor average initial trajectory of about 30° to the horizontal. E. Effects of the Invention The spray pattern created by the apparatus according to the present invention has a high spray density and sharp boundaries of the spray pattern. The spray produced by this type of device is therefore compact and has a steep trajectory. It has also been found that operation of the rotor head according to the invention requires lower power consumption than conventional rotors, as shown by the following figures.

[Table] From the above figures, the effective current used to drive the rotor (from loaded to unloaded) ranges from 2.5 to 3.25 A for a conventional rotor and from 1.25 to 2.25 A for a rotor head according to the invention. I understand that there is something. When magnified by the density factor (molten lead/water), this means that the effective current in lead is 26 to
34A, for the rotor head according to the invention from 13 to
Indicates that it is 24A. F. Examples and Effects The present invention will be described in further detail with reference to the accompanying drawings. In Figures 1a and 1b, reference numeral 1 designates the condenser, reference numeral 2 designates the cross-duct between this condenser and the furnace shaft, and reference numeral 3 designates the inlet to the furnace shaft. As can be seen from FIG. 1a, the spray pattern produced by the rotor head according to the invention is more compact and sharply contoured and has a steeper trajectory than that according to the prior art, so that the spray does not reach the furnace and condenser. less tendency to reach into the cross duct between the first stage and the first stage, resulting in less deposits in the cross duct (due to cooling of the brickwork) and reduced furnace shutdown time. FIG. 2 shows a typical three-blade impeller for use in a device according to the invention. The apparatus according to the invention may be used for purposes other than condensing metal vapors, for example it may find application in metal spray smelting and in the removal of impurities from molten metals by vacuum techniques.

[Brief explanation of drawings]

FIG. 1a shows a rotor head (impeller) according to the invention superimposed on a cross-section of the first stage of a lead droplet condenser.
The outline of the spray pattern created by is shown. Figure 1b shows the outline of the spray pattern produced by a prior art rotor head used in a lead droplet condenser, according to the findings of GB 1263165. Second
The figure shows a typical rotor head. 1...Condenser, 2...Cross duct, 3...Furnace shaft inlet.

Claims (1)

Claims: 1. Apparatus for dispersing a liquid, as droplets, in a gas for the purpose of heat transfer or mass transfer, the apparatus comprising: In an apparatus in which at least one droplet spray envelope is created by rotation of a rotor head immersed in the liquid, the rotor head is a multi-blade helical impeller having a pitch-to-diameter ratio between 0.6 and 1.7. A device characterized in that it takes the form of 2. In the device according to claim 1,
A device characterized in that the impeller has three blades and a pitch-to-diameter ratio of 0.75 to 0.85. 3. A method of dispersing a liquid, as droplets, in a gas for the purpose of heat transfer or mass transfer, the method comprising a rotor head mounted on a substantially vertical shaft and at least partially immersed in the liquid. A method in which at least one droplet spray envelope is created by rotation, characterized in that the rotor head takes the form of a multi-blade helical impeller with a pitch-to-diameter ratio between 0.6 and 1.7. Method. 4 In the method described in claim 3,
A method in which the liquid is a molten zinc/lead alloy used to condense zinc vapor. 5 In the method described in claim 4,
The outer peripheral tip speed of the rotor is 8m/sec to 25m/sec.
method, characterized in that the depth of immersion below the static lead surface of the rotor is between 100 mm and 150 mm. 6. The method according to any one of claims 3 to 5, characterized in that the impeller has three blades and a pitch-to-diameter ratio of 0.75 to 0.85. Method.