FR2585111A1 - Additional primary radiating furnace, introduced into the original furnace of boilers, to improve the combustion and reduce, in the atmospheric emissions, the proportion of pollutant elements - Google Patents

Abstract

Device for improving the combustion of a fuel in boilers, reducing the proportion of pollutant elements in the atmospheric emissions. The invention consists in an additional primary radiating furnace introduced into the original furnace of a boiler to increase the combustion efficiency, by increasing the effects of the radiation on the flame, thus increasing the temperature on its periphery. This is important, in particular, when the volume of the flame is relatively small in relation to the volume of the original furnace of the boiler. The device consists essentially of an additional primary radiating furnace 1 in the form of a sleeve which is introduced into and held in a suitable place in the original furnace 2 and surrounds as closely as possible the flame 3 on all or part of its range. This additional primary radiating furnace 1 is perforated over its entire periphery to allow the calories developed by the flame 3 easily to reach the heat-exchange surfaces of the boiler. The additional primary radiating furnace, subject of the invention, in a case in which its faces are covered with a refractory mineral material, can be impregnated with a gaseous or liquid catalytic agent. This catalytic agent, under the effect of the temperature, accentuates the beneficial action of the radiation on the combustion.

Description

 The present invention relates to a device for improving the combustion of a fuel inside a boiler hearth and, consequently, increasing the combustion efficiency, thereby reducing the proportions of solid unburnt and gaseous therefore air pollution. This is essential when the burner is operating at reduced power compared to the maximum boiler power.

 It is known that the formation of. solid and gaseous unburnt is due, in part, to poor heat radiation from the walls of the hearth on the flame and to cooling @@ ement of its periphery by the combustion air at a temperature always lower than that of the flame.

 It is known, at @ si, that the quality of the radiation from the walls on the flame has a capital importance on the quality of combustion and that this radiation is proportional to the 4th power of the temperature and conversely p @ proportional to the distance from the periphery of the flame to the surrounding fireplace walls.

 The purpose of the present invention is to remedy the harmful effects of poor combustion, by installing inside the hearth of a boiler, a primary hearth related to the volume of the flame.

 To this end, the method according to the invention consists in installing, in the original furnace of the boilers, an additional radiant primary furnace whose perforated walls are as close as possible to the flame, while allowing the calories developed loped by this flame to be transmitted to the heat exchange surfaces of the boilers.

 Figure 1 is a schematic view @, in cross section, of the device, by way of non-limiting example. It shows the position of the additional primary focus radiating 1 inside the original focus 2 and surrounding the flame 3 as closely as possible.

 Figure 2 is a schematic view in longitudinal section of the device, by way of non-limiting example. According to the invention, the additional primary radiating hearth 1 placed inside the original hearth 2 surrounds the flame 3 over all or part of its length to obtain the maximum desired effect on combustion by radiation. The radiant primary hearth is open at both ends.

 According to the invention, the additional primary radiating hearth can be made up of one or more parts, @uivant a @@ ction any geometric compatible with the means of realization.

 FIGS. 3 and 4 show, by way of nonlimiting example, the cross-section, circular or polygonal, that the additional primary radiating hearth can have.

 According to the invention, the wall or walls of the additional primary radiating hearth are perforated to allow the calories developed by the flame to more easily reach the heat exchange surfaces of the boiler. The openings in the walls can have any shape.

 Figures 3 and 4 show, by way of nonlimiting examples @, the shapes that can have the aforementioned openings 4.

 According to the invention, the additional primary radiant hearth is kept countered with respect to the axis of the flame, and inside the original hearth, by appropriate supports or fixings of any shape. schematic 1 shows, by way of non-i @ itative example, a fixing di @ positive 3 constituted by adjustable cross-pieces and on which rests the additional primary radiating hearth 1, inside the original hearth 2 , centered around the flame 3.

 According to the invention, the additional primary radiant hearth, can be made of an openwork metallic material, forming an armature. This frame can be covered, by projection, for example, of a refractory mineral material, by leaving the openings of the frame.

 According to the invention, all the metal parts constituting the additional primary radiant hearth and its fastening elements may be made of refractory steel resistant to the high temperatures prevailing in the hearths of boilers.

 According to the invention, the refractory mineral material, when it exists, constituting in part the additional primary radiant hearth, can be impregnated with a gaseous or liquid catalytic agent.

This catalytic agent, under the effect of temperature, accentuates the beneficial action of radiation on combustion.

Claims (7)

 1 - Device for improving the combustion of a fuel in a boiler by reducing the proportion of imbrAlés, in particular when the power developed by the brader is reduced compared to the maximum power of the boiler, characterized in that it comprises a tubular element (1) with constant dimensions, intended to be placed inside the original fireplaces (2) of the boilers to surround the flame (3) and thus constitute an additional primary radiant firebox, with constant geometry .  2 - Device according to claim 1, characterized in that the tubular element (1), constituting the additional primary radiating hearth, with constant geometry, has a cross section of any geometric shape, but of dimensions appropriate to the volume of the flame (3).  3 - Device according to claims 1 and 2, characterized in that the tubular element (l), constituting the additional primary source radiating at constant geometry, is open at its two ends, to allow the free development of the flame (3 ).  4 - Device according to any one of claims 1 to 3, characterized in that the length of the tubular element (1), constituting the additional primary focus with constant geometry, is chosen to accompany the flame (3) on all or part of its course in the original home (2).  5 - Device according to any one of claims 1 to 4, characterized in that the tubular element (1) constituting the additional primary focus with constant geometry, has openings (4) over its entire periphery to allow the passage of calories developed by the flame (3) towards the heat exchange walls of the original hearth (2).  6 - Device according to any one of claims 1 to 5 characterized in that the tubular element (1), constituting the additional primary focus with constant geometry, is made of refractory metallic material or, in part, of refractory mineral material , in both cases by providing the peripheral apertures (4) on the surface of the tubular element (1).  7 - Device according to any one of claims 1 to 6, characterized in that the mineral material constituting, in part, the tubular element, forming the additional primary radiating focus (1), is impregnated with a liquid catalytic agent or gaseous, this catalytic agent accentuating the beneficial action of the radiation on the flame (3).