An industrial furnace for heating products such as steel products includes a thermally insulated enclosure, a plurality of burners arranged in the enclosure for heating products passing from one end of the enclosure to the other, the burners being distributed over a plurality of temperature-regulated heating areas, and a recovery system designed for recovering heat energy from recovery fumes, The recovery system includes a rotary regenerator associated with each heating area, each of the rotary regenerators being configured to receive a predetermined flow rate of recovery fumes via a first duct, receive a predetermined flow rate of supply air via a second duct, preheat the supply air in order to supply the burners of the associated heating area with a predetermined flow rate of preheated combustion air via a third duct, and discharge exhaust fumes via a fourth duct.

A thermally efficiency regenerative air preheater 250 extracts more thermal energy from the flue gas exiting a solid fuel fired furnace 26 by employing an alkaline injection system 276. This mitigates acid fouling by selectively injecting different sized alkaline particles 275 into the air preheater 250. Small particles provide nucleation sites for condensation and neutralization of acid vapors. Large particles are injected to contact and selectively adhere to the heat exchange elements 542 and neutralize liquid acid that condenses there. When the deposit accumulation exceeds a threshold, the apparatus generates and utilizes a higher relative percentage of large particles. Similarly, a larger relative percentage of small particles are used in other cases. Mitigation of the fouling conditions permits the redesign of the air preheater 250 to achieve the transfer of more heat from the flue resulting in a lower flue gas outlet temperature without excessive fouling.

One embodiment is directed to an oven for heating fibers. The oven comprises a plurality of walls forming a chamber and a supply structure disposed within the chamber between first and second ends of the chamber. The supply structure is in communication with a first heating system and is configured to direct heated gas from the first heating system into a first portion of the chamber. The supply structure is in communication with a second heating system and is configured to direct heated gas from the second heating system into a second portion of the chamber.

To provide a cement production apparatus in which heat-exchanging efficiency can be improved by even pre-heating by supplying material equally to cyclones above a duct and which can perform an operation with low pressure loss and small energy consumption. A cement production apparatus includes: a duct 21 provided between upper cyclones 13A and a lower cyclone 13B being provided below the upper cyclones 13A, the duct 21 in which the exhaust gas drained from the lower cyclone 13B flows upward, distributing and introducing the exhaust gas to the upper cyclones 13A; a plurality of material-supplying pipes 22 for supplying cement raw material provided on the duct 21 below a distribution part 23 to the plurality of the upper cyclones 13A with a same number of distribution outlets 21a among the upper cyclones 13A; and connection ports 22a of the material-supplying pipes 22 to the duct 21 each provided at each of positions corresponding to swirl flows of the exhaust gas poured into the distribution outlets 21a.

Methods and systems for producing direct reduced iron having increased carbon content, comprising: providing a reformed gas stream from a reformer; delivering the reformed gas stream to a carbon monoxide recovery unit to form a carbon monoxide-rich gas stream and a hydrogen-rich gas stream; and delivering the carbon-monoxide-rich gas stream to a direct reduction furnace and exposing partially or completely reduced iron oxide to the carbon monoxide-rich gas stream to increase the carbon content of resulting direct reduced iron. The carbon monoxide-rich gas stream is delivered to one of a transition zone and a cooling zone of the direct reduction furnace. Optionally, the method further comprises mixing the carbon monoxide-rich gas stream with a hydrocarbon-rich gas stream.

Employing furnace combustion gases for both thermochemical regeneration and heating of regenerators to preheat oxidant for the furnace provides synergistic efficiencies and other advantages.

A kiln system is provided, including a drying section, a preheating section, a firing section, a soaking section, a cooling section, and a decarburization section arranged between the drying section and the preheating section. The decarburization section includes an ignition zone, a hot air combustion/pyrolysis zone, and a waste heat recovery pipeline. A heat source is introduced into the ignition zone so that the temperature of the ceramsite of the raw materials with heating values in the zone is 400 C. to 900 C. The hot air combustion/pyrolysis zone is configured for combusting or pyrolyzing carbon-containing materials and organic components in the raw materials with heating values in the ceramsite. The waste heat recovery pipeline is configured for discharging decarburization exhaust gas and recovering heat released after the raw materials with heating values in the ceramsite are combusted or pyrolyzed in the decarburization exhaust gas.

A kiln system is provided, including a drying section, a preheating section, a firing section, a soaking section, a cooling section, and a decarburization section arranged between the drying section and the preheating section. The decarburization section includes an ignition zone, a hot air combustion/pyrolysis zone, and a waste heat recovery pipeline. A heat source is introduced into the ignition zone so that the temperature of the ceramsite of the raw materials with heating values in the zone is 400 C. to 900 C. The hot air combustion/pyrolysis zone is configured for combusting or pyrolyzing carbon-containing materials and organic components in the raw materials with heating values in the ceramsite. The waste heat recovery pipeline is configured for discharging decarburization exhaust gas and recovering heat released after the raw materials with heating values in the ceramsite are combusted or pyrolyzed in the decarburization exhaust gas.

Disclosed is a thermochemical regenerative combustion method in which a mixture of fuel components that can, and cannot, undergo endothermic reaction is passed through a heated regenerator to obtain improved heat recovery efficiency.

The present application discloses a pellet flue gas circulation and waste heat utilization process and a system thereof, which relates to the technical field of flue gas treatment. The system includes a grate, a rotary kiln, an annular cooler, and ducts connecting each part. On the basis of not changing the existing process a flue gas circulation unit and intelligent control equipment are arranged additionally in the present application. The process is simple, and not only can ensure the parameter stability of the production system such as temperature, gas flow or gas pressure, but also can make full use of the low and medium temperature flue gas components and the waste heat, so as to achieve net zero waste gas discharging, energy saving and emission reduction.