GB2151762A

GB2151762A - Reactors and industrial furnaces

Info

Publication number: GB2151762A
Application number: GB08431795A
Authority: GB
Inventors: Hans-Georg Boege; Heinz Estel
Original assignee: DESSAU ZEMENTKOMBINAT
Current assignee: DESSAU ZEMENTKOMBINAT
Priority date: 1983-12-23
Filing date: 1984-12-17
Publication date: 1985-07-24
Also published as: DE3442693A1; GB8431795D0; DD223513A1; FR2560367A1; GB2151762B

Abstract

Reactors and industrial furnaces, e.g. rotary kilns, shaft furnaces and heat exchangers, subject in use to thermal stress are made from prefabricated refractory concrete components (1, 2, 3). The structural strength and refractory requirements are simultaneously satisfied by the prefabricated concrete components, obviating the need for an outer steel casing. The concrete components may be provided with internal steel reinforcement 4, and an outer layer 5 of insulating concrete may also be provided. <IMAGE>

Description

SPECIFICATION Reactors and industrial furnaces The invention relates to reactors and industrial furnaces, for example revolving tubular furnaces, rotary drying kilns, pipes, shaft furnaces and flue gas shafts.

Cylindrical and other tubular reactors and industrial furnaces, for example revolving tubular furnaces, rotary drying kilns and heat exchangers, have been made for centuries from lengths of steel pipe. A refractory lining is provided in order to protect the steel construction and also for reasons connected with the processes carried out in the reactor or furnace.

This prior construction of reactors and industrial furnaces has the following major drawbacks: manufacture and repair require large amounts of highgrade steel, the elasticity of the steel material leads to deformation of the construction and consequential destruction of the refractory lining, the different thermal expansions of the steel construction and the refractory lining lead to problems with the stability of the lining and therefore to operating malfunctions, the refractory lining requires the production of special refractory bricks in a large number of formats, the wear of the refractory lining requires costly clearing work and complicated brickwork operations, as a result of the high weight of the refractory lining, plant constructions using large amounts of steel with correspondingly large foundations are required, the refractory lining has no constructive properties with respect to the stability of the plant.

An object of the invention is to decrease plant costs for the construction and operation of reactors or industrial furnaces subject to high thermal stresses, to increase operating safety and to avoid the drawbacks of known constructions.

Another object of the invention is to provide a substantial reduction in the amount of steel used for the construction and operation of reactors or industrial furnaces subject to high thermal stresses and to replace this steel by other materials.

In accordance with the invention, the reactor or industrial furnace is produced from prefabricated concrete components which are embodied as integral construction elements, with the result that the constructional safety and stability requirements, requirements concerned with method techniques and the refractory lining requirements of the prefabricated concrete components can be simultaneously satisfied. In accordance with the invention, reactors and industrial furnaces are therefore produced in which the refractory lining, the constructional stability requirements and the requirements concerning method techniques are integrated by the use of prefabricated concrete components.

Thus, the invention provides a reactor or furnace, comprising a chamber subject in use to thermal stresses assembled from prefabricated concrete components in such a manner that the components provide at least a major part of the structural strength of the chamber.

In an example of the invention, a reactor or industrial furnace comprises multilayer prefabricated concrete components which are in the form of tubes with reinforced, externally disposed ribs, or internal reinforcement and which are connected together positively or frictionally in a fixed or detachable manner.

The advantages of the invention reside in that the stability specifications of the steel structure or the steel cladding and the function of the refractory lining are structurally combined. This provides the following advantages: the use of steel is minimized in the manufacture and repair of plant of this type, deformations do not occur in practice, heat expansion problems between the steel cladding and the refractory lining are countered, there is no need for costly clearing work with respect to worn refractory linings, the manufacture of special refractory bricks is no longer required and the repair of these reactors and industrial furnaces can be carried out using modern technologies, such as guniting and by the replacement of individual prefabricated concrete components.

Further advantages are produced for example in the case of revolving tubular furnaces, as the heat expansion problems between the furnace cladding and the raceway are countered, problems relating to the heating system are not critical, in particular as refractory concrete enables rapid heating, thermal insulation may be substantially improved, as the prefabricated concrete components may be formed in several layers possibly using insulating concrete, and the detrimental effect of the deformation of the steel cladding is obviated with respect to the refractory lining.

In order that the invention may be more fully understood and readily carried into effect, an embodiment thereof will now be described by way of example with reference to the single Figure of the accompanying drawings which shows a section of a cylindrical or similarly shaped industrial furnace subject to a high thermal stress level, for example a heat exchanger for use in the cement industry, which comprises prefabricated concrete components as follows: Lower portion 1, upper portion 2 and cover 3, are produced from refractory concrete selected to accommodate the thermal stresses encountered in each appropriate zone, and are provided with an internal reinforcement 4, e.g. steel reinforcement.

A heat insulation layer 5 is also provided, which may be formed of insulating concrete. The prefabricated concrete components are connected together positively, detachably and in a gas-tight manner.

The advantages of the invention consist in that there is no longer any need for the separate, exposed, structural steel cladding used in conventional construction methods. Also an improved heat insulation is provided and there is no need for clearing of refractory linings or for special refractory bricks for the linings. Repair may be carried out by concreting, guniting or by the replacement of individual prefabricaed concrete components.

Additionally, lining losses as a result of different heat expansions between the steel cladding and the refractory lining are countered.

The invention can also be used in shaft furnaces, revolving tubular furnaces and rotary drying kilns, to allow the conventional steel structure and steel cladding to be omitted.

Claims

1. A reactor or furnace, comprising a chamber subject in use to thermal stresses,assembled from prefabricated concrete components in such a manner that the components provide at least a major part of the structural strength of the chamber.

2. A reactor or furnace as claimed in claim 1, wherein the chamber is tubular and said components include internal reinforcement members.

3. A reactor or furnace as claimed in claim 1 or 2, and including a heat insulating layer.

4. A reactor or furnace as claimed in claim 3, wherein said heat insulating layer is formed of concrete.

5. A reactor or furnace as claimed in any preceding claim, wherein the concrete components are connected together positively or frictionally in a detachable or a fixed manner.

6. A reactor or furnace comprising a chamber, subject in use to thermal stresses, comprising a chamber formed of reinforced concrete having no steel reinforcement or cladding externally of the concrete; whereby the strength of the chamber is provided at least substantially by the strength of the reinforced concrete.

7. Cylindrical and similarly shaped reactors and industrial furnaces with high thermal stresses, characterised in that they are produced from prefabricated concrete components, which substantially or completely undertake the structural strength and stability specifications and the technological specifications of reactors and industrial furnaces and the specifications of the refractory lining.

8. A reactor or furnace substantially as hereinbefore described with reference to the accompanying drawings.

9. A revolving tubular furnace in accordance with any preceding claim.