F. L. Smidth & Co.

F. L. Smidth & Co., A/s

Jorn Touborg

Mogens Juhl Fons

A bed (6; 78) of particulate material, which is supported by a gas distribution bottom (9; 75), is located utilizing a treatment gas, which via ducts (19; 35; 77) is conducted in sectionalized manner to and directed up through the gas distribution bottom and the bed of material from one or several underlying compartments (15; 76). The flow of the treatment gas through each duct (19; 35; 77) is self regulated by means of a flow regulator (21) provided in each duct. It is thereby obtained that the total pressure loss across the gas distribution bottom can be reduced, that the flow of the treatment gas through the material bed is distributed in a desirable and well-defined manner across the entire gas distribution bottom regardless of the composition of the material bed and the distribution thereon, and that tunnel formations are avoided.

Method and apparatus for treating a bed of particulate material

A method for the continuous treatment of particulate material, such as cement raw meal, in an apparatus comprising a stationary reactor (6) configured as a conical spouted bed, to which the material is fed and treated in a suspended bed by means of gas which, via a centrally arranged gas inlet (21), is injected at the bottom of the reactor (6) and flows upwards through the reactor (6), and wherefrom the material is discharged via an opening (21) at the bottom of the reactor (6). The dimensions, operating parameters of the reactor (6, 21) or the volumes of the connected apparatuses (8a) are selected and regulated in such a way that during operation the bed pulsates up and down in the reactor (6) at such an amplitude that a quantity of the bed material which corresponds to the quantity of flesh feed material, when the bed is situated in its lowermost position, is brought into a zone (22) in which the gas flow velocity is lower than the minimum velocity required for suspending the bed particles, and thereby drops through the gas flow out of the reactor (6).

Method and apparatus for continuous treatment of particulate material

A tubular reactor for heat treatment of granular material in suspension has a vessel (1) up through which a flow of gas and burning fuel passes. The vessel contains vanes (20) which cause the gas to follow a helical path and fling outwards entrained material, which falls down the vessel wall and is displaced inwardly by frusto-conical rings (30).

Gas suspension reactor

A method is disclosed for treating granular or pulverous raw material in a kiln plant including a preheater stage, a precalciner stage and a separator stage coupled to one another. Precalcined material is separated after the separator stage into a first and second material flow. The first material flow is suspended in spent cooling air and fed to a reaction zone zone for burning and melting the material therein. The melted material is fed to a cyclone for separating smoke gases therefrom and thereafter to a rotating nodulization drum. The second material flow is also fed to the rotating nudulization drum and mixed therein with the melted material so as to avoid any sticking and clogging of the melt. A kiln for practicing the method of the present invention is also disclosed. In preferred alternative embodiments, the reaction chamber can be either a shaft-like chamber or a cyclone burner.

Method and plant such as a kiln plant for treating granular or pulverous

A method is disclosed for operating a cement kiln plant in which impurities in the form of alkalis are present in vapor form in the hot dust laden gases generated in the kiln. According to the method, a portion of the hot dust laden kiln gases are directed upwardly through a first riser pipe which communicates with the kiln exit gas opening and thereafter the dust particles are separated from the gases and directed to the bottom portion of a second riser pipe having its lower end open to the atmosphere. Relatively cold atmospheric air is directed upwardly through the second riser pipe so as to contact the kiln dust particles separated from the by-passed kiln gases of the first riser pipe thus permitting the kiln dust particles to be cooled by the cold air while causing the air to be heated and providing its further use e.g. in a preheater. The velocity of the cold air directed through the second riser pipe is preferably controlled such that the heavier of the alkali kiln dust particles are permitted to fall downwardly through the second riser pipe countercurrent to the flow of air while the lighter of the kiln dust particles are entrained in the upwardly flowing air. Ultimately the kiln gases from the first riser pipe are combined with the preheated air from the second riser pipe and the combined gases may be directed to preheaters. Thus the method permits the removal of the heavier alkali laden particles from the cement kiln system by merely removing those particles from the second riser pipe. A cement kiln plant for practicing the inventive method is also disclosed.

Cement kiln plants

A method of firing a rotary kiln for the production of cement clinker is disclosed. The method includes the step of directing at least a major portion of the amount of fuel necessary for firing the kiln so as to be brought into direct contact with hot cement clinker in a precooling zone of the rotary kiln. There is further disclosed an apparatus for the production of cement clinker from cement raw meal. The apparatus comprises an inclined rotary kiln having a precooling zone in the lower end portion thereof in which cement raw meal collects and means for directing a jet of fuel into direct contact with hot cement clinker in the precooling zone of the material downstream end of the rotary kiln.

Method of firing a rotary kiln and apparatus therefor

A method is disclosed for burning alkali-containing raw materials such as cement raw meal in a plant having a multiple string cyclone preheater, each string containing at least two cyclone preheater stages, a kiln, and a cooler unit for cooling the burnt material from the kiln by means of air which is subsequently divided into two streams, one stream being passed through the kiln and a kiln string of the preheater, the other stream being passed through a calciner and up through the calciner cyclone string of the preheater. According to the invention, the flow of material from the penultimate preheater cyclone stage of the kiln string is directed to the calciner, at least a part of the material from the penultimate cyclone stage of the calciner string is directed to the lowermost cyclone stage of the kiln string, and at least a remaining portion of the material from the penultimate cyclone stage of the calciner string is passed to the calciner.

Method of burning pulverous alkali-containing raw materials and kiln

A method of heat treating a preheated, pulverous, raw material consisting of or containing lime, such as cement raw meal. By mixing at least part of the preheated raw material intimately with a fuel capable of carrying out at least a partial calcination, a suspension of raw material in a combustible gas is provided. Upon providing a flow of oxygen-containing gas in contacting relation with the suspension of gas/material, at least a partial calcination takes place according to an endothermic process in which calcium carbonate is dissociated into calcium oxide and carbon dioxide. A finishing calcination and/or other heat treatment may follow the calcination process. When the raw material is cement raw meal, the aforesaid finishing heat treatment following the calcination is a sintering by which cement clinker is produced according to an exothermic process. A unique calcination plant is disclosed for at least partially calcining a preheated pulverous, raw material according to the present method wherein by a supply of heat before the material is subjected to a finishing calcination and/or other heat treatment, if any, at least a partial calcination may be performed approximately isothermically and at a relatively low temperature.

Calcination of pulverous material

An improved method is disclosed for heat treating a preheated, pulverous raw material such as cement raw meal wherein a stream of oxygen containing gas is directed through a calcination chamber and the preheated raw meal and a calcining fuel are fed separately therein in a manner which provides mixing of the raw meal and the fuel and thereafter creates eddys of the mixture when it contacts the oxygen containing gas. The combined stream is directed out of the chamber and particles of raw meal are separated therefrom. A calcination plant is disclosed for practicing the method of the invention and a rotary kiln plant is disclosed for burning cement raw meal in a manner which includes at least partial calcination according to the inventive method.

Method of burning pulverous raw material and rotary kiln plant therefor

A method of heat treating a preheated, pulverous raw material consisting of or containing lime, such as cement raw meal. Preheated pulverous raw material is accumulated in a lower portion of a calcination chamber and a substantially incombustible gas is introduced into the accumulation at a sufficient velocity to traverse the accumulation to cause surface portions to overflow a weir. An oxygen-containing gas is introduced into a flame chamber overlying the accumulation. At least one flame is maintained within the flame chamber by burning a fuel therein. The heat necessary for at least partially calcining particles of raw materials suspended in the incombustible gas and oxygen-containing gas is transmitted from the flame to the suspension of raw materials. The treated materials may then be subjected to a finishing calcination and/or any other final heat treatment. An improved calcination plant is disclosed for at least partially calcining a pulverous raw material according to the method of the present invention wherein the heat necessary for at least partially calcining the preheated fluidised raw material is supplied by at least one flame which is maintained in a flame chamber through the introduction of at least one burner pipe into the flame chamber of the plant.

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Copenhagen, Denmark

Jorn Touborg