Patent Application
20080031697
The present invention relates to a pipe part for conveying a solid particulate material.
Examples of a pipe part suitable for conveying a solid particulate material at low to moderate pressure (i.e. up to about 15 bar) are described in U.S. Pat. No. 6,227,768, DE 12 69 571 and WO 2004/087331.
The pipe part disclosed in U.S. Pat. No. 6,227,768 includes an inner conduit adapted for transporting particulate material from the first end to the second end of the conduit and having a gas permeable wall, which inner conduit is longitudinally disposed in an outer conduit having an impermeable wall. The outer conduit in first and second ends is provided with inwardly protruding sealing support rings wherein the inner conduit is rigidly fixed in the outer conduit so that a gas distribution chamber is situated between the outer conduit and the inner conduit and the inwardly protruding sealing support rings. A compressed gas inlet nozzle traverses the outer conduit and a gas pressure source is attached to the gas inlet nozzle conveying gas to the gas distribution chamber and through the gas permeable wall.
A pipe part as disclosed in U.S. Pat. No. 6,227,768 can be used in a pipe system for transporting loads of solid particulates such as powders at relatively moderate temperatures and pressures. Such a pipe systems can for instance be provided downstream of a storage silo or a hopper for particulate materials.
In operation, the external gas pressure traverses the gas permeable inner conduit to assist the transport of the resident or entrained particulate materials.
A problem of the pipe part as disclosed in U.S. Pat. No. 6,227,768 is that, when it is connected with other pipes sufficiently tight to contain elevated pressures and or temperatures, it is anticipated that the inner conduit will damage under mechanical loads resulting from the connections.
Depending on the materials used, axial loading resulting from differences in thermal expansion between the inner and outer conduits might lead to damage of the inner conduit.
The above problem is even more pertinent in case the pipe part is to be used in a pipe system for transporting pulverised coal and fly ash in coal gasification plants. Coal gasification is known in the art and involves the partial combustion of solid particulate carbonaceous materials such as coal, petroleum coke and biomass. The partial combustion process is generally carried out at elevated pressures that may be as high as 80 or even 100 bar and at elevated temperatures. Therefore, the pipe system must be suitable for exposure to elevated temperature and/or pressure.
Another drawback of the known pipe part is that replacement of the inner conduit is cumbersome.
Still another drawback of the known pipe part is that inspection of the inner conduit is only possible from one side.
It is an object of the present invention to minimize one or more of the above drawbacks.
It is a further object of the present invention to provide an alternative pipe part that can be exposed to elevated temperatures and/or pressures.
One or more of the above or other objects are achieved by the present invention by providing a pipe part for conveying a solid particulate material at high pressure, the pipe part at least comprising:
wherein the inner tubular element is sealingly connected with the first and second sections to form an aeration fluid distribution chamber between the first and second sections and the inner and outer tubular elements, which aeration fluid distribution chamber is provided with an aeration fluid inlet to define an aeration fluid flow path between the aeration fluid inlet through the aeration-fluid-permeable wall part via the aeration fluid distribution chamber; and
wherein the inner tubular element is flexibly supported by both of the first and second sections.
An important advantage of the pipe part of the present invention is that mechanical loading of the inner tubular element via the outer tubular element is reduced. If connections with other pipes are made via the outer tubular element, then the inner tubular element will be less loaded by forces resulting from such connections than would be the case with a rigidly supported inner tubular element.
A further advantage of the present invention is that the pipe part can be suitably used for transporting solid particulate materials at high temperatures and pressures as high as 80 or even 100 bar.
In a particular preferred embodiment, the inner tubular element is axially slidingly engaged with both of the first and second sections.
Herewith the axial loading of the inner tubular element is strongly reduced as some axial play is still possible for the inner tubular element.
Another advantage of this particular embodiment of the invention is that the inner tubular element can be easily replaced or taken out for inspection by sliding it out of the outer tubular element.
In a further aspect the present invention provides a piping system for conveying a solid particulate material, the pipe system comprising at least one pipe part according to the present invention.
In an even further aspect the present invention provides the use of the pipe part according to the present invention for transporting a solid particulate material in a gasification system.
In another aspect the present invention provides a system for the gasification of a solid particulate material, the system at least comprising:
wherein the piping system comprises at least one pipe part according to the present invention.
The invention will be described hereinafter in more detail and by way of example, with reference to the accompanying non-limiting drawings in which:
In the Figures same reference signs relate to like components.
Referring to
In the vicinity of the first and second ends, first and second sections 9,12 are formed each having have a cylindrical inner wall. These first and second sections 9,12 are axially displaced from each other, and an aeration fluid inlet 15 is traversing the wall of the outer tubular element 1 between the first and second ends. The inlet 15 is connected to a flange 17 for the purpose of fluidly connecting to a source of pressurized aeration fluid.
In this embodiment, the permeable wall part 23 is fully formed out of a permeable material. It is also possible to form the inner tubular element 20 out of a perforated wall which wall itself is impermeable whereby the perforations form the permeable wall part.
Examples of permeable materials include porous resin, sintered metal, sintered metal oxide, sintered glass. In the embodiment of
The diameter of the pores should be large enough to let the gas pass, but small enough to prevent solid particulates to enter the aeration fluid distribution chamber or to clog the pores. Depending on the size distribution of the solid particular material to be conveyed, suitable pore diameters can lie between 1 and 50 μm, or preferably between 1 and 20 μm. For transport of powdered coal and fly ash pore diameters between 7 to 14 μm, preferably having an average pore size of 10 μm has given satisfactory aeration results. The latter has been made from pre-fabricated stainless steel sinter metal type SIKA-R 5 AX from GKN Sinter Metals GmbH mentioned above.
In the vicinity of the inner tubular element ends, the inner tubular element 20 is provided with sealing rings 29, 32 fixed to the permeable wall part 23 via joints 35 and 37. The joints 35, 37 can be welded joints. In their outer peripheral walls, the sealing rings 29, 32 each are provided with a circumferential groove wherein a sealing O-ring 36, 38 is positioned.
The inner tubular element 20 of
An aeration fluid distribution chamber 40 is formed by the annular space the inner and outer tubular elements 20,1 and between the first and second sections 9, 12. An aeration fluid flow path 19 is defined between the aeration fluid inlet 15 through the aeration-fluid-permeable wall part 23 via the aeration fluid distribution chamber 40.
Transmission of mechanical loads from the outer tubular element 1 to the generally more fragile inner tubular element 20 is not so dominant due to the flexible supporting. Axial loads exercised on the outer tubular element 1 are particularly not transmitted to the inner tubular element 20 due to mutual longitudinally sliding engagement.
The pressure containing tubular elements can be made of standard piping parts that need not be specifically adapted. This is an advantage in view of pressure vessel regulations.
Moreover, the inner tubular element 20 can be slided in and out of the outer tubular element 1 for inspection and/or servicing and/or replacement.
In operation, a solid particulate material such as powdered coal or fly ash, is transported through the inner channel 10. At the same time, pressurized aeration fluid such as preferably nitrogen or another inert gas is fed into the aeration fluid chamber 40 via aeration fluid inlet 15. The aeration fluid distributes itself in the distribution chamber 40 and traverses the permeable wall part 23 towards channel 10 to assist the transport of the resident or entrained solid particulates.
A small axial space 45, 48 is maintained between the second connecting flange 43,46 and the sealing rings 29, 32 in order to at least allow compression of the gaskets 41,42 when bolting up the first and second connecting flanges. Some more space for axial play of the inner tubular element 20 relative to the outer tubular element 1 is provided to avoid straining the inner tubular element 20 when extremely thin gaskets are used. An optional flexible spacer ring may be provided between the joints 35 and 37 and the second connecting flanges 43 and 46 respectively, in order to avoid the solid particulates to intrude into the spaces 45 and 48.
Pipes may be directly welded to the second connecting flanges 43 and 46, but in the embodiment as shown in
A second embodiment of the fully assembled pipe aerator is schematically depicted in
An advantage of the second embodiment is that the inner tubular element 20, which is the replaceable part, is cheaper than in the first embodiment because the sealing rings do not form part of it.
A third embodiment of the fully assembled pipe aerator 100 is schematically depicted in
In this embodiment the inner tubular element 20B can only be placed in the outer tubular element 1 in one orientation. This can in particular be advantageous in case that the micro pores in the aeration fluid permeable wall part have an angular orientation relative to the longitudinal direction so that the aeration fluid that traverses the inner tubular element wall is given a longitudinal velocity component that can assist the transport of the solid particulates. Herewith the throughput rate can be increased relative to a random orientation of the micro pores.
The piping system 230 comprises at least one pipe part 100 between the source 210 and the gasification reactor 220.
Further, an oxygen source 250 for feeding an oxygen containing stream via line 260 to the gasification reactor 220 is shown.
After partial combustion of the particulate coal in the gasification reactor 220 thereby producing synthesis gas, slag is removed via line 270 and the synthesis gas is removed via line 280 to undergo further processing, if desired.
As gasification systems as such are known, they are not further discussed here.
The person skilled in the art will readily understand that the invention can be modified in many ways without departing the scope of the appending claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 04106660.6 | Dec 2004 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP05/56765 | 12/14/2005 | WO | 10/1/2007 |
