The present invention concerns an apparatus and a method for manufacturing a product from a raw material. The apparatus comprises a rotary kiln having a first rotary kiln end and a second rotary kiln end, and a cooling unit which is connected to the second rotary kiln end, wherein a process direction is provided leading through the rotary kiln from the first rotary kiln end to the second rotary kiln end and further through the cooling unit, wherein the cooling unit is configured to transport the product in the process direction through the cooling unit for cooling the product, the rotary kiln comprising a burning unit at the second rotary kiln end, the burning unit being configured to receive a flammable material and an ignition gas to create heat inside the rotary kiln and to produce a combustion gas containing carbon dioxide, the rotary kiln being configured to transport raw material received at the first rotary kiln end in the process direction towards the second rotary kiln end, and, by using the heat, to transform the raw material into the product and into a resigning gas comprising carbon dioxide, characterized in that the apparatus comprises a gas outlet configured to remove an exhaust gas comprising the resigning gas and the combustion gas from the rotary kiln, and that the cooling unit is configured to transport a cooling gas in the process direction over the product.

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.

The invention provides a powder-gas heat exchanger for exchanging heat between a powder stream and a gas stream in counter-current flow comprising a powder stream mass flow rate substantially equal to a gas stream mass flow rate in a vertical shaft heat exchanger. A hot gas stream may be adapted for use in heating a cool solids stream, or a cool gas stream may be adapted for use in cooling a hot solids stream.

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 of producing a cementitious material, includes providing a raw material, heating the raw material to a temperature of 100-120 C., the heating including a first heating including heating the raw material to a first temperature in heat exchange with a heat exchanger fluid circulating in a first circulation loop, a second heating including heating the raw material to a second temperature in heat exchange with a heat exchanger fluid circulating in a second circulation loop, the second temperature being higher than the first temperature, calcining the heated raw material in a calciner to obtain a calcined material, cooling the calcined material to a temperature of <150 C. for obtaining the cementitious material, wherein sensible heat removed from the calcined material in the cooling is used as a heat source for heating the heat exchanger fluid circulating in the first and/or second circulation loop.

A method of producing cement clinker and a second calcined material, wherein the cement clinker is produced in a first production line and the second calcined material is produced from a raw material in a second production line by carrying out the following procedures e) optionally drying the raw material in a dryer, g) calcining the optionally dried raw material in a rotary kiln to obtain the second calcined material, wherein the sensible heat of a hot gas in the first production line is used as a heat source in the calcining step g) for calcining the raw material, and wherein the rotary kiln exhaust gas coming from the calcining step g) is introduced into the first production line for the secondary combustion of the rotary kiln exhaust gas.

A device for thermal treatment comprises at least a preheater, a calciner, and a materials cooler, wherein a solids stream is guided into the preheater, from the preheater into the calciner, from the calciner into the materials cooler, and out of the materials cooler, wherein a gas stream is guided into the materials cooler, from the materials cooler into the calciner, from the calciner into the preheater, and out of the preheater, wherein the device comprises a combustion chamber, wherein the gas stream from the materials cooler is guided at least partially through the combustion chamber into the calciner, wherein a residence time device is arranged between the combustion chamber and the calciner.