An integrated fuel combustion system with gas separation (adsorptive, absorptive, membrane or other suitable gas separation) separates a portion of carbon dioxide from a combustion gas mixture and provides for recycle of separated carbon dioxide to the intake of a fuel combustor for combustion. A process for carbon dioxide separation and recycle includes: admitting combustion gas to an adsorptive gas separation system contactor containing adsorbent material; adsorbing a portion of carbon dioxide; recovering a first product stream depleted in carbon dioxide for release or use; desorbing carbon dioxide from the adsorbent material and recovering a desorbed second product stream enriched in carbon dioxide for sequestration or use; admitting a conditioning and/or desorption fluid into the contactor and desorbing a second portion of carbon dioxide to recover a carbon dioxide enriched conditioning stream; and recycling a portion of the carbon dioxide enriched conditioning stream to an inlet of fuel combustor to pass through the fuel combustor for combustion.

A system is provided with a turbine combustor having a first diffusion fuel nozzle, wherein the first diffusion fuel nozzle has first and second passages that separately inject respective first and second flows into a chamber of the turbine combustor to produce a diffusion flame. The first flow includes a first fuel and a first diluent, and the second flow includes a first oxidant. The system includes a turbine driven by combustion products from the diffusion flame in the turbine combustor. The system also includes an exhaust gas compressor, wherein the exhaust gas compressor is configured to compress and route an exhaust gas from the turbine to the turbine combustor along an exhaust recirculation path.

A system is provided with a turbine combustor having a first diffusion fuel nozzle, wherein the first diffusion fuel nozzle is configured to produce a diffusion flame. The system includes a turbine driven by combustion products from the diffusion flame in the turbine combustor. The system also includes an exhaust gas compressor, wherein the exhaust gas compressor is configured to compress and route an exhaust gas from the turbine to the turbine combustor along an exhaust recirculation path. In addition, the system includes a first catalyst unit disposed along the exhaust recirculation path.

Methods and devices for combusting a carbonaceous fuel in an oxy-combustion fluidized bed reactor involving controlling the local oxygen content within the oxy-combustion reactor to specified levels. The carbonaceous fuel and an oxygen-containing gas are introduced into a fluidized bed reactor and eluted through a fluidized bed of an inert material, dolomite or a combination thereof to combust the fuel and oxygen to produce at least CO.sub.2 and steam. The oxygen-containing gas is a mixture of oxygen, recycled CO.sub.2 and steam and has sufficient oxygen added to the recycled CO.sub.2 and steam that the mixture contains 7-20 mole % oxygen. The carbonaceous fuel and the oxygen-containing gas are introduced into the fluidized bed at a location in sufficiently close proximity to each other to avoid producing a reducing atmosphere at the location. At least a portion of the produced CO.sub.2 and steam are recycled to the reactor.

A method for reducing harmful gas emissions from a gas-fired boiler including a sealed forced-draught combustion chamber in which there is a burner to which there leads a first conduit for drawing in combustion air and from which there departs a second conduit for the discharge of combustion flue gases. Provision is made for drawing off a portion of the flue gases or exhaust gases from the second conduit and injecting it into the combustion air to reduce the percentage of atmospheric oxygen present in that combustion air and consequently reduce the production of harmful gases in the combustion flue gases. A boiler operating according to the aforesaid method is also disclosed.

A system is provided with a turbine combustor having a first diffusion fuel nozzle, wherein the first diffusion fuel nozzle has first and second passages that separately inject respective first and second flows into a chamber of the turbine combustor to produce a diffusion flame. The first flow includes a first fuel, and the second flow includes a first oxidant and a first diluent. The system includes a turbine driven by combustion products from the diffusion flame in the turbine combustor. The system also includes an exhaust gas compressor, wherein the exhaust gas compressor is configured to compress and route an exhaust gas from the turbine to the turbine combustor along an exhaust recirculation path.

A combustion gas supply system has an air compressor supplying compressed air, a fuel supply device that supplies a fuel and a combustor that generates a pressurized combustion gas by combusting the fuel and the compressed air. At a gas supply and recovery section, the pressurized combustion gas generated by the combustor is supplied to a heat consumption apparatus, and the pressurized combustion gas after heat consumption is recovered as a used gas. A part of the used gas recovered is supplementarily compressed by a re-pressurizing compressor and supplied to the compressed air.

A dark radiator includes a first burner, a fan and a radiant tube. The first burner is connected to a fuel gas supply, the fan is designed to supply the first burner with combustion air and the first burner is designed to output a flame into the radiant tube. The fuel gas supply is connected to a hydrogen source as a fuel gas source and a secondary burner is connected downstream in the radiant tube spaced apart from the first burner functioning as the primary burner in the flame direction. The fuel gas supply thereof is connected to a hydrogen source as a fuel gas source and the exhaust gas flow of the upstream primary burner is supplied to the secondary burner as combustion air.

The present disclosure provides a method and a system for denitrogenation combustion and CO.sub.2 capture and utilization in a gas boiler. The method is implemented by the system for denitrogenation combustion and CO.sub.2 capture and utilization in the gas boiler, and comprises: after circulating flue gas is discharged from a gas boiler, introducing the circulating flue gas into a gas heat exchanger to perform heat exchange with natural gas, hydrogen, and carbon-based denitrogenation gas; introducing the circulating flue gas after heat exchange into a flue gas dehydration device to perform dehydration; introducing a first portion of the circulating flue gas after the heat exchange and dehydration into a blower through the flue gas dehydration device to be pressurized by the blower and introduced into a carbon-based denitrogenation gas mixer; preparing the carbon-based denitrogenation gas by mixing oxygen and the circulating flue gas using the carbon-based denitrogenation gas mixer for combustion for the gas boiler; and introducing a second portion of the circulating flue gas after heat exchange and dehydration into a CO.sub.2 recovery device to perform purification and deoxygenation through the flue gas dehydration device to obtain a CO.sub.2 product, and pressurizing and transmitting the CO.sub.2 product to a CO.sub.2 utilization device through a CO.sub.2 compressor.

In a method for reducing the NOx emissions of a rotary kiln of a clinker production plant, fuel supplied through a burner of the rotary kiln is burned along with primary air fed through the burner, wherein the primary air has a lower oxygen content and the primary air has an oxygen content reduced relative to that of the ambient air and a temperature increased relative to that of the ambient air, and the primary air is obtained by mixing ambient air with exhaust gas from the rotary kiln or from a heat exchanger connected to the rotary kiln and used for preheating raw meal. The primary air is further obtained by mixing with hot air, in particular waste air from a clinker cooler.