A thermochemical regenerator system is operated without encountering accumulation of unwanted solids on the interior surfaces of the passages through which flue gas passes.

A method for operating a furnace, the method including the steps of: combusting fuel with oxidant, thereby generating thermal energy and fumes, heating the furnace with a first part of the thermal energy generated in step a, evacuating the generated fumes from the furnace at a temperature of at least 900 C., the evacuated fumes containing a second part of the thermal energy generated in step a, and using the second part of the thermal energy generated in step a for heating the oxidant and as a heat source for cracking ammonia in a cracker into a mixture including hydrogen, nitrogen and un-cracked ammonia, at least part of the mixture produced in step d-ii being combusted as fuel in step a with at least part of the heated oxidant produced in step d-i.

Method for indirectly preheating a fluid upstream of a furnace, wherein the fluid is preheated by indirect heat exchange with fumes discharged from the furnace through a medium in a chamber, and wherein the flow rate of the medium in the chamber is adjusted on the basis of at least one of the following temperatures: the temperature of the discharged fumes, the temperature of the medium in the chamber, the temperature of the preheated fluid, and the temperature of the wall separating the discharged fumes from the medium in the chamber.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

Furnace operation includes consecutive cycles of a heating step, a stopping step and a restarting step. The fuel and/or the oxidizing agent is preheated upstream of the furnace by indirect exchange with the discharged fumes through a medium passing through a chamber. A first wall separates the fumes from the medium in the chamber. The fuel and/or oxidizing agent is separated from the medium in the chamber by second wall. During restarting, the medium's flow rate Dm is regulated to limit the heating rate of the first wall until it reaches the operational temperature at an end thereof.

A heat exchanger includes a hollow heat exchanger main body that is enclosed in a radiant tube, and a heat conductor that is disposed on outer periphery of the heat exchanger main body. The heat exchanger performs heat exchange between a first gas flowing in between the radiant tube and the heat exchanger main body and a second gas flowing in hollow interior of the heat exchanger main body, and the heat exchanger comprises a turbulence flow generation promoting unit configured to promote generation of a turbulence flow from the first gas flowing in between the radiant tube and the heat exchanger main body, the turbulence flow generation promoting unit being disposed on the outer periphery of the heat exchanger main body without welding.

A power plant is suggested with an additional heat transfer between the flue gas that flows through a flue gas line (5) and the feed-water in a feed-water line (19). The claimed arrangement of the first heat exchanger (13) upstream and adjacent to a precipitator (7) leads to a reduced space demand and optimizes dust precipitation as well as the pressure drop of the flue gas.

Combustion method and installation in which an oxygen-rich oxidant is preheated by exchange of heat with a heat-transfer fluid, upstream of the combustion chamber, in which method and installation an auxiliary gas is heated by heat exchange with a first proportion of the hot flue gases discharged from the chamber, and in which method and installation the heat-transfer fluid comprises a mixture of at least a proportion of the heated auxiliary gas with a proportion of hot flue gases.

A coal fired oxy boiler power plant is disclosed in which a steam coil oxygen preheater located on an oxygen line Air Separation Unit is thermally integrated with the condensate system. Thermal energy for the steam coil oxygen preheater is provided via an extraction line connected to a steam extraction port of an intermediate pressure steam turbine. A drain line of the steam coil oxygen preheater fluidly connects the steam coil oxygen preheater to a point of the Rankine steam cycle fluidly within the condensate system.