HU208573B - Burner of large activity for melting copper - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to high-efficiency smelting of copper burners, primarily resulting in complete combustion and uniform flame composition, using a wide range of fuels and any gaseous and liquid fuels, even low pressure. The burner can be used to efficiently and productively melt copper cathodes in a vertical shaft furnace without undesirable amounts of oxygen entering the copper.

Creating efficient and productive heating and melting burners is a major industrial and operational problem, especially in today 's times when energy costs are rising, oil supplies are falling, and the types and types of fuel available are changing. The melting of copper cathodes in a vertical fuel-fired furnace is one example of the need for new types of burners to use liquid fuels, such as water gas, atomized water gas, converted natural gas, natural gas, coke oven gas, other natural and man-made gases. These gaseous fuels are usually purchased directly from the low pressure urban gas grid, since boosters are usually not approved, and current burners, which require high pressure gas, do not have the required efficiency for this application.

As is well known to those skilled in the art and as also found in US-PS 3 199977 (A.J. Phillips et al., August 10, 1965), which serves as a reference, copper cathodes are industrially prepared by electrolytic processes. The cathodes are of commercial grade copper, copper, and are usually flat, rectangular in cross section. They are 1 inch (25.4 mm) thick and 25 to 40 inch (635-1016 mm) long, although larger or smaller sizes can be produced.

Although the copper deposited on the cathode is of commercial purity, apart from the usual impurities, the small amount of electrolyte (sulphates) physically present or absorbed on the cathode surface, copper cathodes are generally not used due to their shape and physical properties, due. In order to render it more usable, the cathodes must be fused and the molten metal molded into one or more semi-finished shapes, such as cakes, pendulums, sticks, wires, blocks and rods, or similar shapes from which finished products such as such as plates, wires, tubes, and many other commercial products that can be made from commercially available copper. In addition, if copper is commercially unacceptably contaminated with oxygen and sulfur during smelting, it is essential that the sulfur and oxygen in the copper be reduced in the molten metal to an acceptable degree, either by pre-casting or by electrical poles. However, from a commercial point of view, fused copper is essentially in a state that cannot be used, so it has to be worked through a series of process steps again to form the new cathode. This is a costly and time consuming process.

It is therefore essential that burners used to smelt copper do not contaminate the copper, for example with unwanted oxygen. Generally, the fuel-oxygen (air) mixture ratio is such that it does not contain enough oxygen to completely burn the fuel, and the resulting melting flame is a reducing flame. However, the critical nature of the melting flame requires that, even if the total flame flow is reduced, the undesirable oxidizing effect caused by the presence of unburned oxygen in the flame is avoided. For most industrial applications, the predetermined reduction conditions must be such that the amount of oxygen introduced into the copper during melting is less than 0.05% by weight relative to the copper. Advantageously the preselected reduction! conditions are such that the oxygen introduced into the molten copper is less than 0.035% by weight, but more preferably less than 0.01% by weight.

The burners described in that patent, as well as the burners described in US-PS 4536 152 (Little et al.), Are specifically designed to provide a uniform reducing flame and a commercially pure molten copper product such as the burner shown in Figure 1. U.S. Pat. No. 4,536,152 is incorporated herein by reference.

The burner (3) of Fig. 1, which represents the prior art, includes a mixing section (50) for combining the fuel stream with an oxygen-containing gas (air) stream to produce a uniform flow of this ignition, i.e., flame. drive to the surrounding section (51). The burner body is further provided with a combustion chamber (52) and is mounted on the flange (53) opposite the shoulder (54) of the region (51) surrounding the flame. The spark plug (58) may be located in the nozzles and a conventional electrically operated spark plug (59) mounted on the side of the section (51) to ignite a uniform flow, such that the inner end of the spark plug (59) is adjacent the spark plug (58). a. The combination of the nozzles and the ignition rod (58) is particularly useful for maintaining the combined flow of combustion in the combustion chamber (52), particularly at high fuel flow rates. The section (51) is provided with openings (69 and 70) so that a uniform flow can be sampled.

The mixing section (50) has an annular suction section (60), a sleeve (61), a connecting section (62), a flap opening (63) and a viewing opening (64) provided with a transparent lens (65). The sleeve (61) which strikes the shoulder (66) and the left end of the mixing section (50) cooperates with the annular suction pipe section (60) to provide a suction pipe which is the smaller of the two flows to be joined (usually the fuel flow). ) number2

From the pipe (36) through the openings (67) to the connection chamber (68). The size and number of openings (67) along the circumference of the sleeve (61) are selected to control the flow of fluid into the chamber. The greater flow is led from the tube (29) to the connection chamber (68) through the opening in the plate (63) and through the arc tube portion (62). The tube (36) guides the smaller (fuel) flow to the burner and is provided with a valve (39) for controlling the amount of fuel that enters the burner with positive pressure. The tube (36) is provided with a conventional regulating diaphragm valve (38) having a tube (37) leading from the inside of the tube (29) into the space above the diaphragm, thereby transmitting the air pressure in the tube (29) to the diaphragm. Gaseous fuels have a normal operating pressure of 90 kPa to 140 kPa or more.

When the burner is in operation, the larger of the two flows to be joined is introduced into the burner through an opening into an arc tube leading to the combining chamber and the exact composition of the flow is determined as described in US-PS 3,7777.

Unfortunately, however, low pressure gaseous and / or liquid fuels with a line pressure less than the pressure in the burner require modification of the prior art burners and special operating conditions, which is why it is highly necessary and desirable for the industry to develop a burner which can also be used for this fuel.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above shortcomings by providing a high efficiency burner for melting metals which, without significantly contaminating the metals, allows the use of a wide variety of fuels, including low and high pressure gaseous as well as liquid fuels.

SUMMARY OF THE INVENTION The present invention provides a high-efficiency burner for further improving burners described in U.S. Pat. is connected to the feed gas jet and is provided with an inlet for the delivery of lower mass gas, the gas jets being perpendicular to one another and one of low pressure gas or liquid fuel - the other being an oxygen-containing melting gas which mixes as a mixing aspirator .

In order to improve the pressure mixing section in the known burners, the invention includes an aspirator mixer (suction mixer) which allows, for example, the use of fuels with a lower pressure than air pressure in the burner.

Thus, for example, prior art burners require a water pressure of 3.5 to 3.80 kPa higher than air pressure for operation. When using an aspirator burner according to the invention, the fuel pressure may be less than the air pressure, i.e., the atmospheric pressure.

A further improvement is that, according to the invention, a lens is positioned along the axis of the burner mixing chamber by attaching it to a movable rod which serves to provide an aspirator opening in the burner mixing section. Preferably, the lens is a wide-angle lens that provides a wide angle view of the burner wall. In a very preferred embodiment, a telescopic structure is used, preferably located in a movable bar, so as to focus the lens on a portion of the burner or even the interior of the furnace.

The invention will now be described in more detail with reference to an exemplary embodiment of the burner, in which:

Figure 1 is an enlarged vertical sectional view of a prior art burner;

Figure 2 is a sectional view of the burner suction mixer section of the present invention.

The burner illustrated in Figure 1, which is representative of the state of the art and discussed above, consists of a number of sections and components. 2, the mixing section (50) and the arc tube (62) at or near "A" of Figure 1 are replaced by the mixing section (71). The mixing section (71) can be secured at point "A" by means of screws, flanges or other mechanical seals. In the burner of Fig. 1, the tube (37) leading to the control diaphragm valve (38) is preferably retained, and in a more preferred embodiment, the same tube is connected to the end of the mixing section (71) near point "A". This tube is connected to the tube (37) in a T-piece to provide pressure indication to the control diaphragm valve (38) and increased control over burner operation.

Figure 2 shows that the burner (3) comprises a mixing chamber (72) and a gas supply chamber (72a) along the longitudinal axis of the mixing section (71) with a rod (73) disposed therein forming an annular opening (74). The smaller of the two streams to be combined, via the gas jet opening (74a) (typically the fuel flow) is introduced at the inlet (75) into the larger stream (usually the air stream) which is introduced through the inlet (76) . The lenses (77 and 78) are located at the end of the displacement rod (73); preferably, the lens (78) is a wide-angle lens capable of "glancing", catching, the region (51) and the entire interior of the combustion chamber (52).

In a highly preferred embodiment, a telescopic section (79) is disposed within the bar (73) so that it can be focused on specific portions of the burner (3) or even inside the furnace.

The fuel used to operate the burner is natural gas and it is introduced through the inlet (75) into the air introduced through the inlet (76). Mixing section (71) is provided by North American Mfg. Co. (Cleveland, Ohio), 3065-6, "Aspirator Air Gas Mixer" air-gas suction mixer section,

EN 208 573 Β no moving rod. The dimensions of these burners can be found on pages 1 and 2 of the "Dimensions 30.65.1-87" brochure of this company. The Aspirator provided heat of about 305 kW with a pressure drop of about 5 kPa through the opening (74). The orifice (74) has an annular cross-sectional area of 8.32 cm ² . The pressure of natural gas was 2 kPa and the pressure of air was 6 kPa.

Measurement of the fuel-air mixture at the apertures (69 and 70) showed a uniform mixture, indicating that the flame in the combustion chamber (52) is similarly uniform and provides melting without the need for undesired oxygen supply to the melt. This was proven when the burner was used to melt cathode copper in an industrial shaft furnace.

Exemplary oxygen contents of the cathode and the finished product are 0.1% and 0.2%, respectively.

It will be appreciated that various modifications and modifications to the features described and described herein, which do not depart from the spirit and scope of the invention, are possible. Therefore, it is also to be understood that the embodiment shown and its description are exemplary only, and that the invention is not limited to this embodiment.

Claims (4)

PATENT CLAIMS A high-efficiency copper burner for smelting, adapted to feed a low pressure gas or liquid fuel, characterized in that it comprises a mixing chamber (72) disposed along the longitudinal axis of the mixing section (71) of the burner (3) and a primary gas supply chamber (72a). itself, communicating with the mixing chamber (72) through the opening (74a) of the melting gas jet and forming an inlet (75) for feeding a smaller mass of gas, the gas jets being perpendicular to one another and one of them being low pressure gas or liquid fuel another is an oxygen-containing melting gas which is mixed in the mixing chamber (72) to act as a mixing aspirator (71). Burner according to Claim 1, characterized in that it has axially extending lenses (77, 78) through the mixing chamber (72) which can be viewed downstream from the mixing chamber (72). Burner according to Claim 2, characterized in that the lens (77, 78) is disposed within an axially arranged rod (73) along the longitudinal axis of the mixing chamber (72), one of the lenses (77, 78) being in the combustion chamber. (53) and the other lens (78) is disposed outside the mixing chamber (72). Burner according to Claim 3, characterized in that the axially positioned rod (73) has a telescopic section (79) and is thus capable of focusing near and far.