Burner for the partial oxidation of liquid fuels which contain carbon

This invention relates to a burner for the partial oxidation of liquid, carbonaceous fuel by means of steam and an oxygen-containing gas.

Burners of this kind, which are directed into a combustion chamber, are known for instance from EP 0 127 273 B1, the U.S. Pat. No. 4,933,163 and EP 0 707 880 A1. From the last-mentioned publication it is also known to dispose such burner at the entrance of an empty combustion chamber, the raw product gas produced being cleaned subsequently and being processed for instance to obtain a synthesis gas.

It is the object underlying the invention to create a burner for the partial oxidation of liquid fuels such as heavy oil, which burner is suited for high throughput capacities and at the same time allows an inexpensive operation. In accordance with the invention this is achieved in that at least two fuel-carrying tubes are arranged in parallel, the distance between adjacent, fuel-carrying tubes being 5 to 30 cm, that each fuel-carrying tube is surrounded by a steam-carrying tube, that the orifice end of each steam-carrying tube has a supply line for oxygen-containing gas, and that the steam-carrying tubes are surrounded by a common first cooling chamber through which cooling liquid is passed, the first cooling chamber constituting an annular chamber and extending into the area of the orifice ends of the steam-carrying tubes. The number of fuel-carrying tubes usually lies in the range from 2 to 20 and preferably from 3 to 12.

Due to the common first cooling chamber a compact, relatively simple construction of the burner is obtained, at the same time a sufficient cooling of the area of the orifice ends of the steam-carrying tubes is ensured, which tubes are exposed to the high temperatures in the combustion chamber. At the point where the oxygen-containing gas meets the fuel local temperatures up to about 1700° C. occur. Coaxial to the first cooling chamber a common second cooling chamber is expediently provided, which is surrounded by the first cooling chamber. It may be recommended to provide a connecting passage for cooling liquid between the first and the second cooling chamber.

A further development of the burner consists in that inside the area of the first cooling chamber at least one passage for an insertable and removable auxiliary burner is provided. This auxiliary burner may be used for instance only in the start-up phase of the gasification operation, and it is removed from the burner assembly during the continuous operation.

As liquid, carbonaceous fuel there may for instance be used heavy oil, a pumpable slurry of granular coal or petroleum coke in water or in liquid hydrocarbons, as well as an emulsion of bitumen or asphalt in water. As O 2 -containing gas there is normally used technically pure oxygen or oxygen-enriched air, if the nitrogen content is not disturbing.

Embodiments of the burner will be explained with reference to the drawing, wherein:

FIG. 1 shows a longitudinal section through the burner in a schematic representation, sectioned along line I—I of FIG. 2, and

FIG. 2 shows a cross-section through the burner of FIG. 1, section ed along line II—II.

The burner 1 has a distribution chamber 2 for liquid fuel, here also referred to as first distribution chamber. The liquid fuel is supplied through the inletport 2 a and pressed out through the fuel-carrying tubes 3 . In the present case, four fuel-carrying tubes 3 are connected with the distribution chamber 2 , cf. FIG. 2, of which tubes two are shown in FIG. 1 . Each tube 3 is coaxially surrounded by a steam-carrying tube 4 . The conically tapered shape of the tubes 4 towards the orifice end 4 a is not absolutely necessary. The steam is supplied through an inlet 5 a and first of all enters a second distribution chamber 5 , before it flows out through the tubes 4 . In the orifice area 4 a atomized fuel and steam are mixed before the mixture leaves the burner. Through annular slots 6 a oxygen-containing gas is supplied to the mixture, which gas is required for partial oxidation. The oxygen-containing gas comes from a third distribution chamber 6 and is supplied through the inlet port 6 b.

In the central area of the burner 1 a cylindrical passage 8 is provided, into which e.g. an auxiliary burner, for instance for the start-up phase, can be inserted if necessary. When the auxiliary burner is no longer used, it can be removed from the passage 8 , and the passage can be sealed by means of a lid not represented. The passage 8 is surrounded by a cylindrical wall 9 , which is in contact with a cooling chamber 12 . The cooling chamber 12 , which constitutes an annular chamber and surrounds the passage 8 and the cylinder wall 9 , is referred to as second cooling chamber. The first cooling chamber 11 rests against the inside of the burner housing la, which for instance has a cylindrical shape. The cooling liquid, e.g. water, is supplied through the inlet 11 a and is discharged through the outlet 11 b . Between the first cooling chamber 11 and the second cooling chamber 12 the two connecting passages 13 and 14 are provided, which each extend past a steam-carrying tube 4 . For a better optical clarity the parts of the burner through which cooling liquid flows are represented with dots. By means of not represented flow obstacles in the cooling chambers it is ensured that the cooling liquid preferably takes a flow path as it is necessary for the desired temperatures. It is in particular ensured that the cooling effect also sufficiently exists in the vicinity of the orifice area 4 a of the burner.

In the drawing, which represents the burner only schematically, spacers between the various parts were omitted, so as not to impair the clarity of the representation.

In the present case, four fuel-carrying tubes 3 and the associated steam-carrying tubes 4 are disposed inside the first cooling chamber 11 , but the number of the tubes 3 with the associated tubes 4 can lie in the range between 2 and 20 and preferably 3 and 12 . It may be recommended to dispose these tubes in the area between the first and the second cooling chamber, and to provide a passage 8 for the auxiliary burner in the central area. This passage 8 is, however, not necessary in all cases.