Abstract:
This invention relates to a process and a plant for the heat treatment of solids containing titanium. For this purpose, the fine-grained solids are heated to a temperature of 700 to 1000 °C in a reactor (4) with circulating fluidized bed and are partly discharged from the reactor (4) together with waste gases into a downstream separator (9). In the same, the solids are separated from the waste gases and are recirculated to the reactor (4) at least partly and/or phase by phase. Downstream of the reactor (4) and/or the separator (9) an injection cooler (13) is provided, in which the solids are cooled to below 250 °C by injecting a coolant. Downstream of the injection cooler (13) a fluidized-bed cooler (16) can be provided for the further cooling of the solids.
Abstract:
The present invention relates to a method for the heat treatment of fine-grained solids, in particular gypsum, in which the solids are heated to a temperature of 50 to 1000 °C in a fluidized bed reactor (1), and to a corresponding plant. To improve the energy utilization, it is proposed to introduce a first gas or gas mixture from below through a preferably central gas supply tube (3) into a mixing chamber (21) of the reactor (1), the gas supply tube (3) being at least partly surrounded by a stationary annular fluidized bed (2) which is fluidized by supplying fluidizing gas, and to adjust the gas velocities of the first gas or gas mixture as well as of the fluidizing gas for the annular fluidized bed (2) such that the particle Froude numbers in the gas supply tube (3) are between 1 and 100, in the annular fluidized bed (2) between 0.02 and 2 and in the mixing chamber (21) between 0.3 and 30.
Abstract:
This invention relates to a process for producing e.g. anhydrous metal oxide from metal hydroxide, wherein the metal hydroxide is at least partly dehydrated and preheated, before the metal hydroxide is introduced into a fluidized-bed reactor (19), in which the metal hydroxide is heated to a temperature of about 650 to about 1250°C by combustion of fuel, and metal oxide is generated, wherein primary air and/or secondary air enriched with oxygen is supplied to the fluidized-bed reactor (19). To achieve a rather low dust emission and a small amount of grain disintegration, the oxygen or the gas enriched with oxygen is introduced into the fluidized-bed reactor (19) with a low gas velocity.
Abstract:
This invention relates to a process and a plant for the heat treatment of solids containing titanium. For this purpose, the fine-grained solids are heated to a temperature of 700 to 1000 °C in a reactor (4) with circulating fluidized bed and are partly discharged from the reactor (4) together with waste gases into a downstream separator (9). In the same, the solids are separated from the waste gases and are recirculated to the reactor (4) at least partly and/or phase by phase. Downstream of the reactor (4) and/or the separator (9) an injection cooler (13) is provided, in which the solids are cooled to below 250 °C by injecting a coolant. Downstream of the injection cooler (13) a fluidized-bed cooler (16) can be provided for the further cooling of the solids.
Abstract:
The present invention relates to a method and a plant for the heat treatment of solids containing titanium and possibly further metal oxides, in which fine-grained solids are heated to a temperature of 700 to 950 °C in a fluidized bed reactor (1). To improve the energy utilization, it is proposed to introduce a first gas or gas mixture from below through a gas supply tube (3) into a mixing chamber (7) of the reactor (1), the gas supply tube (3) being at least partly surrounded by a stationary annular fluidized bed (10) which is fluidized by supplying fluidizing gas. The gas velocities of the first gas or gas mixture as well as of the fluidizing gas for the annular fluidized bed (10) are adjusted such that the particle Froude numbers in the gas supply tube (3) are between 1 and 100, in the annular fluidized bed (10) between 0.02 and 2 and in the mixing chamber (7) between 0.3 and 30.
Abstract:
This invention relates to a process for producing e.g. anhydrous metal oxide from metal hydroxide, wherein the metal hydroxide is at least partly dehydrated and preheated, before the metal hydroxide is introduced into a fluidized-bed reactor (19), in which the metal hydroxide is heated to a temperature of about 650 to about 1250°C by combustion of fuel, and metal oxide is generated, wherein primary air and/or secondary air enriched with oxygen is supplied to the fluidized-bed reactor (19). To achieve a rather low dust emission and a small amount of grain disintegration, the oxygen or the gas enriched with oxygen is introduced into the fluidized-bed reactor (19) with a low gas velocity.
Abstract:
A process for producing water-free aluminium oxide from aluminium hydroxide in a circulating fluidised bed comprising a fluidised bed reactor (8), separator (6) and return flow line involves the following steps: the aluminium hydroxide is fed into the gas-side second stage of a two-stage suspension pre-heater (2) operated by the waste gases from the fluidised bed reactor (8) of the circulating fluidised bed and at least partially dewatered; dewatered aluminium hydroxide from the second stage of the suspension pre-heater (2) is fed into the gas-side first stage of a suspension pre-heater (5) operated by the waste gases from the fluidised bed reactor (8) of the circulating fluidised bed, further dewatered and then fed into the circulating fluidised bed which is operated by oxygen-containing fluidisation gas (10) indirectly heated in a subsequent cooling stage by the aluminium oxide produced and by oxygen-containing directly heated secondary gas (11) fed in at a higher level. The temperature in the circulating fluidised bed is set at between 850 and 1000 DEG C. The aluminium oxide removed from the circulating fluidised bed is mixed for at least two minutes with 10 to 25 wt.% of the partially dewatered aluminium hydroxide yielded by the solid-side first stage of the suspension pre-heater (2) and led past the circulating fluidised bed as a by-pass. The mixed material is then cooled in a multistage suspension cooler (15, 16, 17, 18, 19, 20), heating secondary gas (11), and then in the fluidised bed cooler (23), indirectly heating fluidisation gas (10).
Abstract:
When fluidizing a fluidized bed, which forms a fluidized bed (3) of solid particles, in a vessel (1), the fluidizing gas is introduced into the fluidized bed via a pipeline (7) in the vicinity of the vessel base (9), the gas flow in the pipeline (7) being directed substantially continuously downwards. A flow resistance (10) which is arranged above the fluidized bed (3) is provided in the pipeline (7).
Abstract:
The present invention relates to a process for producing metal oxide from metal com pounds, in particular metal hydroxide or metal carbonate, in which the metal compound is conveyed into a reactor (25) with fluidized bed, heated there to a temperature of 650 15 to 1150°C by combustion of fuel, and metal oxide is generated, as well as to a corre-sponding plant. To improve the utilization of energy, it is proposed to introduce a first gas or gas mixture from below through a gas supply tube (26) into a mixing chamber (20) of the reactor (25), the gas supply tube (26) being at least partly surrounded by a stationary annular fluidized bed (27) which is fluidized by supplying fluidizing gas, and 20 to adjust the gas velocities of the first gas or gas mixture and of the fluidizing gas for the annular fluidized bed (27) such that the Particle-Froude numbers in the gas supply tube (26) lie between 1 and 100, in the annular fluidized bed (27) between 0.02 and 2, and in the mixing chamber (20) between 0.3 and 30.