In methods of and/or plants for manufacturing cement clinker, the amount of chloride bypass exhaust gas 79 can be substantially decreased, when using previously cooled chloride bypass exhaust gas 81 and/or cooled kiln exhaust gas as coolant for the chloride bypass exhaust gas 39 prior to deducting the chloride bypass exhaust gas 39.

To produce cement clinker by baking of raw meal in a kiln, use is conventionally made of a raw meal preheater in which the heat of the flue gas emerging from the kiln is transferred to the raw meal. In order to remove impurities which accumulate in circulation between the kiln and the raw meal preheater, a part of the flue gas is extracted from the kiln, bypassing the raw meal preheater. The heat generated during the baking of cement clinker can be used particularly efficiently if the flue gases extracted and diverted past the raw meal preheater are used in a boiler to generate hot steam which can subsequently be expanded in a turbine.

To produce cement clinker by baking of raw meal in a kiln, use is conventionally made of a raw meal preheater in which the heat of the flue gas emerging from the kiln is transferred to the raw meal. In order to remove impurities which accumulate in circulation between the kiln and the raw meal preheater, a part of the flue gas is extracted from the kiln, bypassing the raw meal preheater. The heat generated during the baking of cement clinker can be used particularly efficiently if the flue gases extracted and diverted past the raw meal preheater are used in a boiler to generate hot steam which can subsequently be expanded in a turbine.

To provide a fractionating device capable of stably fractionating powders such as cement raw materials by a simple configuration. A fractionating device 1 for fractionating some of a powder (cement raw material) R falling in a chute (main body) 2, wherein the fractionating device is equipped with a screw conveyor 5 which passes through the chute, a part of a casing 5a opening inside the chute, and receives part of the powder from an opening (inlet) 5b, and a collision separation member (collision separation rod) 4 which is provided above the screw conveyor in the chute and collides with an object when an object of a predetermined size or larger falls, and prevents the object from falling directly onto the screw conveyor. A rotation shaft 5d of the screw conveyor may be inclined from 5 to 20 with respect to the horizontal plane so that the end of the discharge port side of the screw conveyor is positioned above the other end and may be equipped with a guide member 3 that guides the powder falling in the chute in the direction of the opening of the screw conveyor.

Denitrifying bypass exhaust gases in a cement clinker producing plant. The plant comprises a rotary kiln connected to a calciner for the deacidification of raw material or to a rotary kiln riser shaft via a rotary kiln inlet chamber, and the bypass exhaust gas being drawn off in the region of the rotary kiln inlet chamber. The method comprises: cooling the bypass gas to between 260 C and 400 C in a cooling device, injecting an ammonia-, urea-, and/or ammonium-containing substance into the cooled bypass gas, introducing the cooled and mixed bypass gas into a ceramic filter system to filter out any halide and sulfate of the alkali metals and alkaline-earth metals precipitated during cooling the gas, and any nitrogen not reacted by the injected substances is chemically selectively reduced over a catalytic converter which is located in or directly downstream of the ceramic filter system.

Methods and apparatus for reducing the content of controlled acidic pollutants in clinker kiln emissions are disclosed. The methods and apparatus include introducing bypass dust produced during production of clinker into one or more locations between the preheater exhaust and the inlet to a dust filter including into a gas conditioning tower. Total bypass dust separated from the kiln exhaust gas may be used. The bypass dust can be separated into a fine and coarse portions. Fine or total bypass dust can be mixed with water to form a bypass dust slurry that can be introduced into the gas conditioning tower. Bypass dust can be used to reduce the content of acidic pollutants such as hydrogen chloride HCl and sulfur oxides SO.sub.x from clinker kiln emissions.

A Portland cement production (PCP) process is conjoined with a waste-to-energy (WTE) process using refuse-derived fuels (RDFs). Both processes operate simultaneously to reduce harmful compounds being discharged into the environment. The PCP and WTE processes are conjoined by borrowing a minor portion of pre-heated comminuted limestone from a PCP process feedstream and diverting it to the WTE process. Some of the pre-heated comminuted limestone is converted to CaO. The calcium compounds from the pre-heated comminuted limestone act as a fluxing agents and sorbents to bind with and remove undesired impurities, such as elemental particulate matter, excess CO.sub.2 and acid gasses associated with sulfur and chlorine that are released during the pyrolization of RDFs. The ash, char waste and reacted calcium compounds from the pyrolization process can be comingled and returned to the PCP process as a secondary cement meal feedstock.

A method for cleaning bypass gases of the cement or mineral industry includes cooling down a removed bypass gas from a cement or mineral processing plant to a temperature of between 500 C. and 150 C., and coarsely dedusting the bypass gas, the dust burden being reduced by 30 to 95%. After the dedusting step, the gaseous constituents contained in the partly dedusted bypass gas are reduced in a reducing step. The partly dedusted bypass gas is further finely dedusted. The gaseous constituents reducing step includes at least a catalytic reduction of one or more of nitrogen oxides, hydrocarbons, and carbon monoxide.

Methods and apparatus for reducing the content of controlled acidic pollutants in clinker kiln emissions are disclosed. The methods and apparatus include introducing bypass dust produced during production of clinker into one or more locations between the preheater exhaust and the inlet to a dust filter including into a gas conditioning tower. Total bypass dust separated from the kiln exhaust gas may be used. The bypass dust can be separated into a fine and coarse portions. Fine or total bypass dust can be mixed with water to form a bypass dust slurry that can be introduced into the gas conditioning tower. Bypass dust can be used to reduce the content of acidic pollutants such as hydrogen chloride HCl and sulfur oxides SO.sub.x from clinker kiln emissions.

Methods and apparatus for reducing the content of controlled acidic pollutants in clinker kiln emissions are disclosed. The methods and apparatus include introducing bypass dust produced during production of clinker into one or more locations between the preheater exhaust and the inlet to a dust filter including into a gas conditioning tower. Total bypass dust separated from the kiln exhaust gas may be used. The bypass dust can be separated into a fine and coarse portions. Fine or total bypass dust can be mixed with water to form a bypass dust slurry that can be introduced into the gas conditioning tower. Bypass dust can be used to reduce the content of acidic pollutants such as hydrogen chloride HCl and sulfur oxides SO.sub.x from clinker kiln emissions.