Material handling systems for fluids are disclosed herein. The fluid may be a liquid, solution, slurry, or emulsion. The systems receive as inputs the fluid, steam, and water. These feed into a surge tank where additives can be introduced. The steam and water are used to control some physical properties and enable the distribution of the fluid as desired. In particular embodiments, the system is useful for handling materials to be sent to a dual-phase fuel feeder for combustion in a fluidized-bed boiler, the energy being used to generate electricity or in various production processes.

A reactor system and control method. The method includes feeding solid fuel and oxygen containing gas to a first fluidized bed reactor to form a fluidized bed of particles and combusting a first portion of the fuel in the bed with the oxygen containing gas to generate hot bed particles and a first stream of hot flue gas, conveying the first stream to the flue gas channel, transferring hot bed particles including a second portion of the solid fuel at a predetermined hot particles transfer rate from the first reactor to a second fluidized bed reactor, feeding fluidizing gas to the second reactor to form a second fluidized bed, and transferring bed particles from the second reactor to the first. The method includes first and second operation modes. In the first, the fluidizing gas is oxygen containing gas and, in the second, the gas includes steam, CO.sub.2, or inert gas.

The invention relates to processes for recycling waste materials containing valuable metals in a fluidized-bed furnace (100), comprising the phases I, start-up of the fluidized-bed furnace; and II, continuous reprocessing of the waste materials containing valuable metals, characterized in that the fluidized-bed furnace (100) is operated autothermally during the phase II of continuous reprocessing of the waste materials containing valuable metals, with the process temperature being regulated via the fill level of the fluidized-bed furnace (100) and the flow rate of material through the furnace. The invention further provides an apparatus comprising a fluidized-bed furnace (100) for recycling waste materials containing valuable metals in a continuous autothermal process.

The invention relates to a method for operating a fluidized bed boiler, comprising carrying out the combustion process with a fluidized bed comprising ilmenite particles, wherein the average residence time of the ilmenite particles in the boiler is at least 75 hours. The invention further relates to ilmenite particles obtainable by a corresponding method and the use of said ilmenite particles as oxygen-carrying material.

Material handling systems for fluids are disclosed herein. The fluid may be a liquid, solution, slurry, or emulsion. The systems receive as inputs the fluid, steam, and water. These feed into a surge tank where additives can be introduced. The steam and water are used to control some physical properties and enable the distribution of the fluid as desired. In particular embodiments, the system is useful for handling materials to be sent to a dual-phase fuel feeder for combustion in a fluidized-bed boiler, the energy being used to generate electricity or in various production processes.

The invention relates to a method for operating a fluidized bed boiler, comprising carrying out the combustion process with a fluidized bed comprising ilmenite particles, wherein the average residence time of the ilmenite particles in the boiler is at least 75 hours. The invention further relates to ilmenite particles obtainable by a corresponding method and the use of said ilmenite particles as oxygen-carrying material.