A method for reducing pollution in a cement kiln environment and a system for treating cement kiln exhaust gas are provided. The method includes the steps of: treating a cement kiln exhaust gas stream with a treating fluid, such as a water soluble alkaline-earth metal sulfide. In one application, the treating fluid is injected by spraying droplets into the cement kiln exhaust gas stream. A system for treating cement kiln exhaust gas includes a reagent containing a water soluble alkaline-earth metal sulfide in water, and a nozzle to spray the reagent into the cement kiln exhaust gas stream.

A method for manufacturing clinker includes sintering raw meal in a kiln to clinker, preheating the raw meal (prior to sintering the raw meal) in a preheater using a main flue gas stream from the kiln as heat source, dedusting the main flue gas downstream of the preheater at a temperature below the boiling point of mercury (thereby obtaining mercury loaded dust) and withdrawing a bypass flue gas stream from the kiln. The method is configured to efficiently remove mercury from the manufacturing process if mercury in the bypass flue gas is vaporized by injecting of at least a fraction of the mercury-loaded dust into the bypass flue gas stream. Subsequently, the bypass flue gas is dedusted and cooled down. Thereby, the mercury can be adsorbed by injecting an adsorbent (such as activated charcoal) into the bypass flue gas. With subsequent removal of the adsorbent, mercury is finally removed from the manufacturing process.

A process for producing caustic calcined magnesia (CCM) includes calcining a magnesium containing material, such as magnesite, in a primary calciner to produce a primary calcined material and a primary exhaust comprising dust; subjecting the primary exhaust to separation to recover a dust material includes incompletely calcined dust particles; calcining the dust material in the secondary calciner to produce calcined dust, wherein the dust material is not co-calcined with the magnesium containing material or the primary calcined material. The primary calcined material and the calcined dues thus form two CCM products, which can be kept separate or combined. The primary calciner can be a multiple hearth furnace (MHF) while the secondary calciner can be a gas suspension calciner (GSC). Using a secondary calciner in such a manner can increase throughput of the primary calciner and provide other advantages for the calcination process.

A method for denitrification of flue gases and a system, wherein flue gases generated in a rotary kiln are conveyed to a calcining zone for the deacidification of raw cement meal. Aqueous ammonia solution, ammonia, or ammonia-releasing substances for denitrifying the flue gases injected into the calcining zone according to the method of selective non-catalytic reduction (SNCR), and the flue gas stream, together with an ammonia slip generated during the denitrification, is passed through a heat exchanger and through at least one dedusting device. The flue gas is guided through a exhaust gas line via a catalyst for the decomposition of excess ammonia with residues of nitrogen oxide in accordance with a method of selective catalytic reduction (SCR), wherein the catalyst is arranged in a reactor provided in the exhaust line, and is no larger than is required for a sufficient decomposition of the ammonia.

A method for reducing pollution in a cement kiln environment and a system for treating cement kiln exhaust gas are provided. The method includes the steps of: treating a cement kiln exhaust gas stream with a treating fluid, such as a water soluble alkaline-earth metal sulfide. In one application, the treating fluid is injected by spraying droplets into the cement kiln exhaust gas stream. A system for treating cement kiln exhaust gas includes a reagent containing a water soluble alkaline-earth metal sulfide in water, and a nozzle to spray the reagent into the cement kiln exhaust gas stream.

A method for decreasing an amount of a harmful substance of a chlorine-containing off-gas stream formed or used in a thermal treatment of a material may comprise dividing the chlorine-containing off-gas stream into a main stream and a substream, separating at least some chlorine from the main stream, lowering an amount of the harmful substance in the main stream by introducing a chlorine-containing additive into the main stream to enhance separation of the harmful substance, and filtering the substream such that a filter cake separated from the substream comprises at least part of the chlorine-containing additive.

A calcium-containing composition with fixed CO.sub.2 is produced by contacting a mixture of a calcium-containing composition before CO.sub.2 fixation and water with a CO.sub.2-containing gas. The calcium-containing composition, liquid water, and the CO.sub.2-containing gas having a temperature between 20 degree Celsius and 300 degree Celsius and a CO.sub.2 concentration between 1 volume % and 100 volume % are supplied to a reactor. By the supplied CO.sub.2-containing gas, the calcium-containing composition and water are made to flow in the reactor. Alternatively, the calcium-containing composition and water are in the reactor. Thus, CO.sub.2 is fixed in the calcium-containing composition and simultaneously the calcium-containing composition is dried to a water content of 5 mass % or less.

A method and a sensor device for evaluating residual Sulphur in a cement preheater of a cement kiln, wherein the residual Sulphur is based on the values of the fuel Sulphur content, the fuel rate of consumption, the hotmeal quality and the clinker Sulphur content. A method for evaluating blockage in a cement preheater includes evaluating the residual Sulphur in the cement preheater, determining an agglomeration rate of Sulphur compounds agglomerating on an inner surface of the cement preheater based on the residual Sulphur, and evaluating a level of blockage in at least one predetermined pathway of the cement preheater using a blockage evaluation unit, wherein the level of blockage is based on the agglomeration rate.

Disclosed is a bypass system for use with off gases that have exited a cement kiln utilized in a cement making process. The bypass system is adapted to remove both NOx and volatile components that are present in the off gases while the off gases are in the bypass duct.

A system for carbon capture includes an oxy-fuel combustor for combusting a hydrocarbon with pure oxygen to produce heat energy and carbon dioxide, a COS converter for converting the carbon dioxide to COS, a transport means for transporting the COS, a sulphur recovery unit for recovering sulphur from the COS and an adjunct sulphur-burning power plant for combusting the sulphur to generate energy for powering one or more carbon capture and storage processes.