GB2139343A - Gas burner - Google Patents

Abstract

The burner comprises a water- coolable elongate housing (1) having at one end separate inlets for individual gas flows of oxygen (7), steam (12) and combustible gas (2) and at the other end an outlet for discharge of the combined gas flows and a distributing grid (3) to distribute the combustible gas flow upstream of the said outlet. Oxygen is supplied through pipe (7) to a receiver (8) provided with a first grid (9) in which an arrangement of pipes (10) is secured. Steam is supplied through an annular conduit defined between pipe (11) and pipe (7), which pipe (11) extends to a receiver (13) provided with a second grid (14) with an arrangement of pipes (15) secured therein. Combustible gas is supplied through an annular conduit defined between an outer pipe (1) surrounding the pipe (11) and pipe (11) itself, which pipe (1) leads to a third grid. The burner is employable in chemical industry, e.g. for the cleavage of natural gas with oxygen gas and steam, and is reliable in operation within a wide combustible gas, oxygen and steam loading range. (Figure 1). <IMAGE>

Description

SPECIFICATION Gas burner The present invention relates to a gas burner which can be used in the chemical industry, e.g. for the cleavage of natural gas with oxygen gas and steam.

A gas burner has been proposed which consists of a water-cooled housing with a distributing grid also serving as a water-cooled base for the housing, as well as sections successively built into the housing for the purpose of feeding in combustible gas and oxygen gas, with tubular grids in which pipes are secured, the pipes for the supply of oxygen gas being coaxially built into the pipes for the supply of combustible gas and the latter being secured by their outlet ends in the distributing grid (USSR Inventor's Certificate No. 330306, Cl.G 23 D 15/04,1972).

The said burner is liable to suffer from the following major drawbacks: Considerable hydraulic resistance of the burner to combustible gas and oxygen gas, due to the use of sections for feeding them in, which have to be installed in the housing in succession to one another and necessitate very long combustible gas and oxygen gas supply channels.

The burner is comparatively unreliable in operation, because the distribution grid (base of the housing) is indirectly close to the root of the gas-oxygen flame, so that this part burns away, and the pipes for the supply of oxygen gas are built into the pipes for the supply of combustible gas, the flow of com- bustible gas and the flow of oxygen gas coming into direct contact with each other at the outlet, whereby (particularly when the loading is reduced or altered, the pressure increased etc.) rapid ignition takes place and the pipes for the oxygen gas supply rapidly burn away, so that the burner automatically ceases to operate.

Another previously proposed apparatus is a gas burner consisting of a water-cooled housing with pipe sockets and a distributing grid with a system of apertures, which also serves as a water-cooled base for the housing, as well as a ventral pipe with a manifold, which is provided with a tubular grid at the end, with small pipes which are fixed in the grid and which are brought out through a system of apertures provided therein (Ger. Dem. Rep.

Pat. Specification WP No. 146765 Cl. F 23 D / 17/00 1981).

In the said burner discussed in the previous paragraph the combustible gas flows through a central pipe into the manifold and the pipes leading out of the distributing grid. Oxygen gas passes through a pipe socket into the housing and through an annular gap between the housing and the central pipe to the distributing grid of the housing, then continuing through annular gaps between the small pipes and the edges of the apertures of the distributing grid and coming in contact with the combustible gas. A drawback of this previously proposed burner is its comparative unreliability, because the pipes for the gas feed are installed in the apertures of the distributing grid of the housing, the oxygen gas passing through this grid.This causes the flow of gas and the flow of oxygen gas to come in direct contact with each other at the outlet, with the result that (particularly when the load is reduced or altered or the pressure raised etc.) the pipes for the combustible gas feed ignite and burn away prematurely and the burner thus ceases to operate, the distributing grid (base of the housing) being positioned in the indirect vicinity of the root of the gasoxygen flame and therefore frequently burning away.

The purpose of the invention is the provision of a gas burner which will operate reliably and is capable of being used with a wide combustible gas, oxygen gas and steam loading range.

According to the invention there is provided a gas burner comprising a water-coolable elongate housing having at one end thereof separate inlets for individual gas flows of oxygen, steam and combustible gas and at the other end of the housing an outlet for discharge of the combined gas flows and a distributing grid to distribute the combustible gas flow upstream of the said outlet, wherein there is provided a first pipe centrally of the housing for supply of oxygen gas, the first pipe extending to a first receiver provided with a first tubular grid, with an arrangement of pipes secured in the first tubular grid, which pipes lead out of the said distributing grid, a second pipe surrounding the said first pipe and defining therebetween an annular conduit for supply of steam, the second pipe extsnding to a second receiver provided with a second tubular grid with an arrangement of pipes secured therein, which pipes also lead out of the said distributing grid, an outer third pipe surrounding the said second pipe and defining therebetween an annular conduit for combustible gas, which third pipe leads to the said distributing grid, wherein the first receiver is situated within the second receiver and the pipes of the first receiver pass through the pipes of the second receiver and the said distributing grid houses the first and second tubular grids.

One suitable form of distributing grid may take the form of a plate adapted to be disposed transversely within the outlet end of the housing, the plate having apertures to accommodate the pipes of the first and second receivers and to permit passage of combustible gas from the third pipe to the said outlet.

Another suitable form of distributing grid may take the form of an annular plate adapted to be disposed transversely within the outlet end of the housing, the plate containing within the annulus accommodation for the pipes of the first and second receivers and also permitting passage of combustible gas from the third pipe to said outlet and the inside edge of the inner periphery of the annulus being profiled to exhibit spaced apart semi-circular regions concave towards the centre of the plate.

By way of example a gas burner embodying the invention will be described with reference to the accompanying drawings, wherein: Figure 1 shows a longitudinal section through a gas burner, Figures 2 and 3 show cross-sections through the burner employing differing distributing grids.

The gas burner consists of a water-cooled housing 1 with a socket 2 for a combustible gas feed, with a distributing grid 3 and a double walled casing 4 for cooling the burner, which casing 4 is fitted with sockets 5 and 6 for the feed and discharge of water respectively, a central pipe 7 for the supply of the oxygen, with a receiver 8, which is fitted with a tubular grid 9 with pipes 10 affixed thereto, a section of piping 11 with a socket 12 for the supply of steam, and with a receiver 1 3, which is provided with a tubular grid 14 with annular pipes 1 5 secured therein.The receiver of the central pipe 8 is situated inside the receiver of the section of piping 1 3. The pipes of the receiver of the central pipe 10 are situated coaxially inside the pipes of the receiver of the section of piping 1 5, forming an annular gap. The said pipes 10 and 1 5 head out of the distributing grid 3 of the housing.

The distributing grid 3 of the housing is situated within the latter, at a certain distance from the discharge end surface of the said housing. This arrangement of the distributing grid 3 enables the outlet end of the housing to be regarded as a uniform cylindrical outlet nozzle of the burner. Figure 2 shows a crosssection through the burner for a version in which the distributing grid takes the form of a plate with a system of apertures, through which the pipes 1 5 lead out, forming a gap.

Figure 3 shows a cross-section through the burner for a version in which the distributing grid 3 takes the form of a ring with a system of depressions with a semicircular profile on the inner surface of the ring, the depresssions being situated around the outer row of pipes 15, forming a gap between them and the pipes.

The described burner operates in the foliow- ing manner: Oxygen is fed in through the central pipe 7 and distributed via the pipes 10, entering the reaction chamber. Steam is introduced via the pipe connection socket 1 2 into the annular chamber between the central pipe 7 and the additional section of piping 11 and enters the gap between the pipes 10 and 1 5, after which it enters the reaction chamber. Natural gas is introduced through the pipe connection socket 2 into the space between the housing 1 and the section of piping I ii, reaches the distributing grid 3 and flows out through the annular gaps between tne pipes 15 and the edges of the apertures of the said distributing grid 3 (device constructed in accordance with Figures 1 and 2).When use is made of the distributing grid 3 taking the form of a ring with a system of depressions around the outer row of pipes j 5 tile gas is discharged towards the centre (device constructed as shown in Figures 1 and 3).

The distributing grid taking the forrn of a disc with a system of apertures (Figure 2) may be used when there are a large number of concentric rows of pipes. When there are only few concentric pipes and these latter are packed very tightly together preference will be given to a grid taking the form of a ring with a system of depressions on the inner suriace (Figure 3). In both cases the gas is discharged from the outlet of the housing 1 in the form of a dense flow in which the pipes for the steam feed and oxygen feed are situated. At the outlet from the burner oxygen and combustible gas are separated from each other by intermediate layers of steam which prevent premature ignition from taking place.Water for the cooling is introduced through the socket 5 into the gap between the housing and the inner wall of the casing. The water surrounds the inner wall and passes through the gap between the inner and the outer wali of the casing to the socket 6 via which it leaves the burner.

The gas burner according to the invention offers the following advantages: 1. Owing to the fact that the annular chamber between the walls or the housing and the central pipe contains a cylindrical section of piping for the supply of steam, with a receive which is equipped with a tubular grid with pipes affixed iio the end, the receiver of the central pipe being situated inside the receiver of the additional section of piping, the combustible gas and the oxygen do not come in contact with each other at the outlet from the burner Bsut are separated by an intermediate layer of steam and are not mixed together until a certain distance from the discharge end surface oQ the burner housing is reached, so that the feed pipes do not burn away.

2. Owing to the fact that the distributing grid is situated inside the housing it is kept away from the root of the flame and is also efficiently protected by a layer of natural gas which absorbs the neat and which moves from the distributing grid to the end of the burner housing, so that the said distributing grid does not become overheated or burn away.

The gas burner proves extremely reliable under any combustible gas and oxygen loading conditions or in the event of alterations to the ratio between the combustible gas and the oxygen, temperature fluctuations, changes in the speed etc. Even a relatively small supply of steam between the flow of combustible gas and the flow of oxygen was found to ensure a safe distance between the end of the burner housing and the root of the flame. On the reproduction of the operating conditions under which the original device had been found to fail the elements of the burner did not overheat or burn away and no such failure of the burner took place throughout the entire period o the test.

Claims (4)

1. A gas burner comprising a water-coolable elongate housing having at one end thereof separate inlets for individual gas flows of oxygen, steam and combustible gas and at the other end of the housing an outlet for discharge of the combined gas flows and a distributing grid to distribute the combustible gas flow upstream of the said outlet, wherein there is provided a first pipe centrally of the housing for supply of oxygen gas, the first pipe extending to a first receiver provided with a first tubular grid, with an arrangement of pipes secured in the first tubular grid, which pipes lead out of the said distributing grid, a second pipe surrounding the said first pipe and defining therebetween an annular conduit for supply of steam, the second pipe extending to a second receiver provided with a second tubular grid with an arrangement of pipes secured therein, which pipes also lead out of the said distributing grid, an outer third pipe surrounding the said second pipe and defining therebetween an annular conduit for combustible gas, which third pipe leads to the said distributing grid, wherein the first receiver is situated within the second receiver and the pipes of the first receiver pass through the pipes of the second receiver and the said distributing grid houses the first and second tubular grids.

2. A gas burner according to Claim 1, wherein the distributing grid takes the form of a plate adapted to be disposed transversely within the outlet end of the housing, the plate having apertures to accommodate the pipes of the first and second receivers and to permit passage of combustible gas from the third pipe to the said outlet.

3. A gas burner according to Claim 1, wherein the distributing grid takes the form of an annular plate adapted to be disposed transversely within the outlet end of the housing, the plate containing within the annulus accommodation for the pipes of the first and second receivers and also permitting passage of combustible gas from the third pipe to said outlet and the inside edge of the inner periphery of the annulus being profiled to exhibit spaced apart semi-circular regions concave towards the centre of the plate.

4. A gas burner according to Claim 1 substantially as herein described with reference to Figure 1 and either of Figures 2 and 3 of the accompanying drawings.