Embodiments herein provide a system for electrically heated gas mixture mediated industrial plant processes providing a fossil fuel free approach. The system utilizes a gas mixture as heating medium that directly transfers heat to a raw material required for processing the raw material into an end product. The gas mixture used as a heating medium can be a byproduct generated during processing or a combination of stable gases that are reutilized and recirculated to carry heat and dissipate the heat at various stages of processing in accordance with a heating medium design loop. The heating medium design loop disclosed is designed such that it eliminates the need of heat management equipment like a Thermal Energy Storage (TES) system used by existing approaches. Entire heating of the plant is carried out using electric gas heaters heated using renewable electric sources to provide the fossil fuel free design.

A method and a corresponding plant for denitrifying bypass exhaust gases in a cement clinker production plant. Raw meal is sintered in a rotary kiln and deacidified in a calciner. A rotary kiln inlet chamber is connected to the calciner directly or by a riser duct. Bypass exhaust gas is drawn off near the inlet chamber. This exhaust gas is guided into a first mixing chamber, in which the exhaust gas is cooled to between 800 and 950 C., then the exhaust gas is guided through a reaction pipeline segment, wherein the dwell time is between 0.5 and 3 seconds and ammonia, aqueous ammonia solution, or ammonia-releasing substances are injected for denitrification. Then the exhaust gas is guided into a second mixing chamber, in which the exhaust gas is cooled to between 150 to 250 C. Then the exhaust gas is guided to a filter for dust removal.

The invention provides a process for producing a cement clinker comprising: (i) mixing one or more starting materials providing each at least one or more of CaO, SiO.sub.2, AI.sub.2O.sub.3, and Fe.sub.2O.sub.3; and, optionally, SO.sub.3, to form a raw meal comprising CaO, SiO.sub.2, AI.sub.2O.sub.3, and Fe.sub.2O.sub.3; and, optionally, SO.sub.3, wherein the molar ratios among the aforementioned oxides is given by Formula I: S(CaO).sub.1(SiO.sub.2).sub.a(Al.sub.2O.sub.3).sub.b(Fe.sub.2O.sub.3).sub.c(SO.sub.3).sub.d, wherein: a is comprised from 0.05 to 1, b is comprised from 0.1 to 0.6, c is comprised from 0.001 to 0.25, and d is comprised from 0 to 0.3 and wherein at least 35% (p/p) of the starting materials of the raw meal have a critical microwaves absorbance temperature (Tc) comprised from 15 to 650 C. and a critical microwaves absorbance time (tc) comprised from 1 min to 1 h; (ii) heating the raw meal by irradiating with microwaves during 15 min to 3 h to reach a sintering temperature comprised from 300 to 950 C.; (iii) maintaining the microwave sintering temperature of step (ii) during 1 min to 3 h by further irradiating with microwaves; and (iv) cooling the clinker obtained in step (iii).

Method of operating a long direct-fired inclined counterflow rotary kiln for the thermal treatment of material and counterflow rotary kiln adapted for same, whereby material to be treated is introduced into the kiln at the inlet end and treated material is evacuated from the kiln at the outlet end, whereby a main combustion zone extends inside the kiln over a distance of to of the internal length L.sub.int of the kiln, whereby a supplementary combustion zone in which supplementary combustion takes place with an oxygen-rich oxidant extends inside the kiln over a distance from the inlet end of at most of the internal length L.sub.int, and whereby no combustion takes place in a heat exchange zone located between the main combustion zone and the supplementary combustion zone.

A method and a corresponding plant for denitrifying bypass exhaust gases in a cement clinker production plant. Raw meal is sintered in a rotary kiln and deacidified in a calciner. A rotary kiln inlet chamber is connected to the calciner directly or by a riser duct. Bypass exhaust gas is drawn off near the inlet chamber. This exhaust gas is guided into a first mixing chamber, in which the exhaust gas is cooled to between 800 and 950 degrees C., then the exhaust gas is guided through a reaction pipeline segment, wherein the dwell time is between 0.5 and 3 seconds and ammonia, aqueous ammonia solution, or ammonia-releasing substances are injected for denitrification. Then the exhaust gas is guided into a second mixing chamber, in which the exhaust gas is cooled to between 150 250 degrees C. Then the exhaust gas is guided to a filter for dust removal.

A process and device separate off a volatile component from the off-gases in cement clinker production. Raw materials for cement clinker production are passed through a preheater with heat exchange with the off-gases and are then burnt in a rotary kiln. Owing to the heating in the preheater, the volatile component bound in the raw materials is vaporized and separated off. A first raw material stream having a relatively high concentration of the volatile component is applied to a first line of the preheater and a second raw material stream having a lower concentration of the volatile component is applied to a second line. The volatile component is separated off from the first substream of the off-gases. The first raw material stream heated to a temperature of at least 250 C. with the first substream of the off gases in the first line is combined with the second raw material stream.

A method of making a cement composite can include contacting an aqueous solution comprising calcium ions with a carbon dioxide source producing a carbonated aqueous solution. Fine particles can be submerged in the carbonated aqueous solution to produce microaggregate particles comprising the fine particles coated with calcium carbonate. The microaggregate particles can be combined with cement particles to produce the cement composite. The cement composite can be used in cementing applications for hydrocarbon wells including for casing liners and well plugs.

The present invention provides a method and system for manufacturing cement wherein ground particles of cement and calcium sulfate are subjected to infrared sensors, laser sensors, or both, so that emanated, irradiated, transmitted, and/or absorbed energy having wavelengths principally within the range of 700 nanometers to 1 millimeter can be monitored and compared to stored data previously obtained from ground cement and sulfate particles and preferably correlated with stored strength, calorimetric, or other data values, such that adjustments can be made to the mill processing conditions, such as the form or amounts of calcium sulfate (e.g., gypsum, plaster, anhydride), or cement additive levels. The strength and other properties of cement can be thus adjusted, and its quality can be more uniform.

A system and a method for generating carbon nanotube (CNT)-reinforced cementitious materials are provided. An exemplary method includes capturing carbon dioxide formed in while calcining cementitious precursors, converting the carbon dioxide to hydrocarbons, producing CNTs on the calcined cementitious precursors from the hydrocarbons, and forming CNT-reinforced, cementitious materials from the calcined cementitious precursors comprising the CNTs.

A plant for production of cement clinker from raw meal, having a calciner for deacidification of the raw meal and a rotary furnace for sintering the deacidified raw meal to give cement clinker. The deacidified raw meal flows through a cyclone preheating stage into the rotary furnace. A reactor is provided upstream of the calciner on the flow path of the rotary furnace offgas to the calciner, to which an inlet for the rotary furnace offgas leads. A corresponding method of operating such a plant wherein fuel is added to the reactor in a superstoichiometric amount in relation to the residence time of the offgases in the reactor, such that carbon dioxide present in the offgases is reduced to carbon monoxide. At least one input air conduit for supplying input air, preferably coming from a tertiary air conduit, is provided at at least one point in the reactor.