MOULDED INSULATION BODIES

Abstract

Moulded insulation bodies, processes for the production thereof and use thereof consisting essentially of ceramic material comprising SiO.sub.2 fibers and Al.sub.2O.sub.3 fibers which has been produced using Al.sub.2O.sub.3 sol as a binder and kilned at a temperature of above 800 C. for insulation of the ends of cracking tubes of a tubular reactor for performing a steam reforming process for generating synthesis gas which project out of the reactor heating space.

Claims

1-7. (canceled)

8. A process for producing self-supporting moulded insulation bodies from a ceramic material comprising SiO.sub.2 fibres and Al.sub.2O.sub.3 fibres, the process comprising the steps of: a) providing a flowable mixture comprising SiO.sub.2 fibres and Al.sub.2O.sub.3 fibres and a binder comprised of an Al.sub.2O.sub.3 sol; b) producing a preform by filling the flowable mixture into a hollow mould; c) kilning the preform at a temperature of at least 800 C.

9. A moulded insulation body obtained by the process according to claim 8.

10. The moulded insulation body according to claim 9, wherein the moulded insulation body has a circular arc profile.

11. The moulded insulation body according to claim 10, wherein the moulded insulation body is in a shape selected from the group consisting of a half shell, a quarter shell, and cylindrical.

12. Use of a moulded insulation body according to claim 8 as insulation material in cracking tubes of a tubular reactor for performing a steam reforming process for generating synthesis gas.

13. The use according to claim 12, wherein an inlet for reactants and an outlet for products are arranged at opposite ends of the cracking tube which project out of a heating space of the tubular reactor, wherein the inlet region and/or the outlet region of the cracking tube are fitted with internal moulded insulation bodies having a circular arc profile.

14. The use according to claim 12, wherein the inlet for the reactants and the outlet for the products are arranged at the same end of the cracking tube which projects out of the heating space of the tubular reactor and in that at the opposite end of the cracking tube a free interior space is present which serves to deflect the gas flow leaving the catalyst bed into a heat exchanger tube arranged inside the catalyst bed, wherein the inlet region and/or the outlet region of the cracking tube are fitted with internal moulded insulation bodies having a circular arc profile and the free interior space is fitted with an internal moulded insulation body which is cylindrical.

15. A process for fitting a cracking tube with at least one moulded insulation body according to claim 9, wherein the moulded insulation bodies are introduced into a region of the cracking tube to be insulated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further features, advantages and possible applications of the invention are apparent from the following description of working and numerical examples and from the drawings. All described and/or depicted features on their own or in any desired combination form the subject matter of the invention, irrespective of the way in which they are combined in the claims the way in which said claims refer back to one another.

[0018] The invention shall be more particularly elucidated with reference to the drawing.

[0019] FIG. 1 shows a cross section of the upper end of a cracking tube which passes through the ceiling of the heating space of a tubular reactor,

[0020] FIG. 2 shows a cross section of the lower end of a cracking tube which passes through the floor of the heating space of a tubular reactor,

[0021] FIG. 3 shows a cross section of a cracking tube having an internal heat exchanger.

DETAILED DESCRIPTION OF THE INVENTION

[0022] In FIG. 1 the upper end 1 of a cracking tube 2 projects through the ceiling 3 of the heating space 4. The cracking tube 2 is not firmly connected to the ceiling 3 in order that the thermal expansion of the cracking tube 2 may be compensated by it growing out of the ceiling 3. A thin-walled, flexible tube 5 connects the upper end 1 of the cracking tube 2 with a distributor tube (not shown) from which the reactant gas is introduced into the cracking tube 2. The reactant gas is conducted through the catalyst fixed bed 6 through the cracking tube 2 to its lower end (not shown). The upper end 1 of the cracking tube 2 is provided with the internal moulded insulation body 7 consisting of the ceramic material according to the invention.

[0023] FIG. 2 depicts by way of example how the lower end 8 of a cracking tube 2 is passed through the floor 9 of a heating space 4. The product gas emerges from the catalyst bed 6 and is introduced into the collection conduit 10. The collection conduit 10 is provided with an internal insulation 11. The lower end 8 of the cracking tube 2 is provided with the internal moulded insulation body 7 consisting of the ceramic material according to the invention.

[0024] FIG. 3 shows how a cracking tube 2 having an internal heat exchanger 12 projects with its upper end 1 from the ceiling 3 of the heating space 4 and with its lower end 8 from the floor 9 of the heating space 4. The feed for the reactant gas 13 through which the gas is introduced into the cracking tube 2 is also shown. The gas then ascends through the catalyst fixed bed 6 in the cracking tube 2 into the turnaround space 14 and flows from there through the heat exchanger tubes 12 into the collection conduit 10 for the product gas. The upper end 1 and the lower end 8 of the cracking tube 2 are provided with the internal moulded insulation body 7 consisting of the ceramic material according to the invention.

INDUSTRIAL APPLICABILITY

[0025] The invention makes it possible to achieve higher service lives of the cracking tubes and accordingly improved economy of the steam reforming process. The invention is therefore advantageously economically employable.

[0026] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.

[0027] The singular forms a, an and the include plural referents, unless the context clearly dictates otherwise.

[0028] Comprising in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of comprising). Comprising as used herein may be replaced by the more limited transitional terms consisting essentially of and consisting of unless otherwise indicated herein.

[0029] Providing in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

[0030] Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

[0031] Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

[0032] All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.

LIST OF REFERENCE NUMERALS

[0033] 1 upper end of a cracking tube [0034] 2 cracking tube [0035] 3 ceiling of a heating space of a tubular reactor [0036] 4 heating space of a tubular reactor [0037] 5 flexible tube [0038] 6 catalyst fixed bed [0039] 7 moulded insulation body [0040] 8 lower end of a cracking tube [0041] 9 floor of a heating space of a tubular reactor [0042] 10 collection conduit for product gas [0043] 11 collection conduit insulation [0044] 12 heat exchanger tubes [0045] 13 feed for reactant gas [0046] 14 turnaround space for gas flow inside the cracking tube