Preheater shell temperature regulator

Abstract

The heat treatment apparatus, such as a precalciner or calciner (1) for heat treating cement raw materials is peculiar in that the metal casing (5) is provided with an external insulation (6) comprising an innermost insulation layer (6a) and at least one outer insulation layers (6b), each insulation layer (6a, 6b) comprising a number of shield elements (7) having a top end (8) and a bottom end (9), where the insulation layers are arranged at different distances from the metal casing (5), thus providing an inner air space (11) between the innermost insulation layer (6a) and the metal casing (5) and at least one outer air space (10) between the innermost insulation layer (6a) and an outer insulation layer (6b), where the metal casing (5) furthermore is provided with a bottom element (17) being connected to and extending outwards from the metal casing (5) at a distance below the bottom end (9); of the innermost insulation layer (6a), thus providing an opening (18) between the inner and outer air spaces (11, 10), where at least one of the outer insulation layers is connected to the bottom element (17) at its bottom end (9). Hence it will be possible to obtain a heat treatment apparatus, which may be better internally insulated to reduce the energy loss, while at the same time the metal casing temperature may be regulated both to avoid overheating and corrosion problems.

Description

technical field [0001] The invention relates to a heat treatment plant, such as a preheater or a calciner for the heat treatment of cement raw meal, comprising a heat treatment compartment delimited by a metal shell, having a refractory lining material and heat insulating material on the inside layer. Background technique [0002] Heat treatment plants of the type described above are well known in industries such as cement manufacturing. This heat treatment process of cement raw meal is usually combined with such as SO 2 , SO 3 , HCL and H 2 It is related to the release of acid gas such as S, which can pass through heat-resistant and insulating materials to reach the metal shell, wherein if the temperature is lowered, the gas can condense on the inside of the metal shell, causing corrosion problems. This corrosion problem can be solved simply by increasing the temperature of the metal housing well above the critical dew point temperature so that the acid will remain in th...

AI Technical Summary

Problems solved by technology

However, the actual use of this system has major problems in maintaining the proper temperature of the metal shell, in fact the metal shell cools too much at the bottom causing serious corrosion problems and too little cooling at the top causes the metal shell to body overheating

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