The present disclosure relates to negative-carbon cement (NC2) production, which can be achieved by integrating carbon dioxide hydrogenation and methane pyrolysis into the cement manufacturing process, using hydrogen gas derived from methane pyrolysis as the fuel for heating, and converting any captured carbon dioxide into solid carbon. The solid carbon can be incorporated into building materials such as portland cement and gypsum boards, fixing the carbon to achieve cradle-to-gate emission reduction.

System and method of low carbon emission production of cement include a conventional kiln, a precipitation reactor in material communications with the conventional kiln, an indirect heated kiln in material communications with the precipitation reactor, and a sequestration module in material communications with the indirect heated kiln and configured to sequester high purity carbon dioxide produced by the indirect heated kiln. The system may further comprise a compressor, in material communications with the indirect heated kiln and the sequestration module and the precipitation reactor, and configured to produce materialized carbon dioxide.

A calcination and cement production apparatus comprising a calciner configured to be heated by combustion of a carbon based fuel and a hydrogen peroxide oxidant composition is disclosed.

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.

Providing an implementable renewable fuel gas plant processes with management of greenhouse gases with minimal changes to existing plant set ups is a technical challenge to be addressed. Embodiments herein provide a system for renewable fuel gas generation and utilization in industrial plants with carbon dioxide as heat carrier. The system design integrates renewable fuel gas (H.sub.2) which is generated within the system and utilized to meet the thermal energy requirements of the production process. CO.sub.2 produced as byproduct of calcination in a process equipment, such as during calcination in cement plant is used as a heat-transferring medium to heat the H.sub.2. Further, the system provides recycling of the generated byproducts by separating the exhaust gases, comprised of CO.sub.2 and H.sub.2O. The H.sub.2O is recycled to generate H.sub.2 via electrolysis. The separated CO.sub.2 again serves as a heat-transferring medium, while the excess CO.sub.2 is sequestrated.

A method for manufacturing cement clinker includes the steps: preheating a raw meal in a first preheater using kiln off-gas to provide a partially preheated raw meal, preheating the partially preheated raw meal in a second preheater to provide preheated raw meal, precalcination of the pre-heated raw meal in a calciner being a circulating fluidized bed reactor by burning fuel with oxygen and recirculated calciner exhaust gas instead of air to provide a precalcined raw meal wherein at least 2 mbar overpressure are adjusted in the calciner, transferring the precalcined raw meal to a rotary kiln for sintering to provide the cement clinker, cooling the cement clinker, and capturing carbon dioxide from a calciner exhaust gas in a carbon dioxide purification unit.

A method for thermal activation of coal gangue and in-situ carbon fixation utilizing waste heat from steel slag is disclosed. By utilizing waste heat from high-temperature molten steel slag, coal gangue is activated to a high pozzolanic activity utilizing the system temperature of a steel slag hot-steaming device, and meanwhile, the CO.sub.2 released in the thermal activation process is captured utilizing the reaction of steel slag with CO.sub.2 to generate stable carbonates, thus achieving permanent carbon sequestration. The present disclosure effectively uses the heat from the hot steel slag discharged from the steelmaking furnace in such a way that the coal gangue is activated while the steel slag undergoes a carbonation reaction, resulting in an increased heat recovery rate during the cooling process of the steel slag.

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 cement clinker producing system, capable of providing a gas containing a carbon dioxide gas at a high concentration by increasing a carbon dioxide gas concentration for a part of an exhaust gas, includes a cyclone preheater to preheat a cement clinker raw material, a rotary kiln to burn the preheated cement clinker raw material so as to provide cement clinker, a calcination furnace to promote decarbonation of the cement clinker raw material, a clinker cooler to cool the cement clinker, a kiln exhaust-gas discharge passages to discharge an exhaust gas generated in the rotary kiln, a combustion-supporting gas supply device to supply a combustion-supporting gas having a higher oxygen concentration than air, a combustion-supporting gas supply passage to guide the combustion-supporting gas to the calcination furnace, and a calcination furnace exhaust-gas discharge passage to discharge a carbon dioxide gas-containing exhaust gas generated in the calcination furnace.

A method for sequestating carbon dioxide from flue gas by using a cement clinker. The products of this method can also be used to prepare microfiber-reinforced cement. The method of the present disclosure is capable of capturing and storing carbon dioxide in flue gas, such as cement kiln flue gas.