The invention relates to a furnace for performing an endothermic process, the furnace including a plurality of process tubes containing a catalyst for converting a gaseous feed, wherein the process tubes are arranged in rows within the furnace, each row of process tubes thereby defining a process tube row, a plurality of inner burners arranged in rows, each row of inner burners being arranged between and parallel to process tube rows, thereby defining an inner burner row, and a plurality of outer burners arranged in rows, each row of outer burners being arranged between and parallel to a process tube row and a furnace wall, thereby defining an outer burner row. A number of burners of an outer burner row is smaller than a number of burners of an inner burner row. The invention also relates to a process for operating a furnace for performing an endothermic process.

The invention relates to a furnace for performing an endothermic process, the furnace including a plurality of process tubes containing a catalyst for converting a gaseous feed, wherein the process tubes are arranged in rows within the furnace, each row of process tubes thereby defining a process tube row, a plurality of inner burners arranged in rows, each row of inner burners being arranged between and parallel to process tube rows, thereby defining an inner burner row, and a plurality of outer burners arranged in rows, each row of outer burners being arranged between and parallel to a process tube row and a furnace wall, thereby defining an outer burner row. A number of burners of an outer burner row is smaller than a number of burners of an inner burner row. The invention also relates to a process for operating a furnace for performing an endothermic process.

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 supercritical CO.sub.2 boiler capable of realizing uniform combustion, corrosion resistance and coking resistance, and a boiler system are provided. The supercritical CO.sub.2 boiler includes a main combustion chamber, an upper furnace, a furnace arch and a flue, wherein a cross section of the main combustion chamber is circular or oval, or is of an N-sided shape, where N>4; at least four burner groups are disposed on the main combustion chamber, each group of burner nozzles corresponding to each burner group includes a recirculating air nozzle, a primary air nozzle and a secondary air nozzle; lateral recirculating air nozzles symmetrically distributed are respectively disposed at two sides of the primary air nozzle, the recirculating air nozzle and the lateral recirculating air nozzle are configured to feed recirculating flue gas or a mixed gas of the recirculating flue gas and secondary air into the main combustion chamber.

A supercritical CO.sub.2 boiler capable of realizing uniform combustion, corrosion resistance and coking resistance, and a boiler system are provided. The supercritical CO.sub.2 boiler includes a main combustion chamber, an upper furnace, a furnace arch and a flue, wherein a cross section of the main combustion chamber is circular or oval, or is of an N-sided shape, where N>4; at least four burner groups are disposed on the main combustion chamber, each group of burner nozzles corresponding to each burner group includes a recirculating air nozzle, a primary air nozzle and a secondary air nozzle; lateral recirculating air nozzles symmetrically distributed are respectively disposed at two sides of the primary air nozzle, the recirculating air nozzle and the lateral recirculating air nozzle are configured to feed recirculating flue gas or a mixed gas of the recirculating flue gas and secondary air into the main combustion chamber.

The invention is directed to a method for heating a process gas in a top or bottom fired reformer, a method for improving the temperature spread over a top or bottom fired reformer, and to a top or bottom fired reformer wherein these methods can applied. This can be achieved by the lane flow rate of at least one outer tube lane being different from the lane flow rate of at least one inner tube lane.

The invention is directed to a method for heating a process gas in a top or bottom fired reformer, a method for improving the temperature spread over a top or bottom fired reformer, and to a top or bottom fired reformer wherein these methods can applied. This can be achieved by the lane flow rate of at least one outer tube lane being different from the lane flow rate of at least one inner tube lane.

A burner system includes a plurality of burners each including a nipple that is brass and a jet that is brass. The nipple in at least some of the burners has a first end that is open and a second end that is closed. The nipple has a side wall between the first end and the second end. The side wall defines a bore that extends through the first end to the second end. The first end, second end, and side wall of the nipple are of integral, one piece, construction free of joints. The nipple hole extending through the side wall and the jet is engaged with the hole.

A burner system includes a plurality of burners each including a nipple that is brass and a jet that is brass. The nipple in at least some of the burners has a first end that is open and a second end that is closed. The nipple has a side wall between the first end and the second end. The side wall defines a bore that extends through the first end to the second end. The first end, second end, and side wall of the nipple are of integral, one piece, construction free of joints. The nipple hole extending through the side wall and the jet is engaged with the hole.

A burner sub-system, a furnace comprising the same, a fuel combustion process and steam cracking process carried out in the furnace. The burner sub-system comprises a barrier wall segment between the burner tip and the flue-gas recirculation (“FGR”) duct, effectively blocking direct gas flow between the burner tip and the FGR duct opening, but without encircling the whole burner tip. The presence of the partial barrier wall has the advantage of preventing the temperature inside the FGR duct from becoming too high, while achieving low NOx emissions from the combustion process without overheating the burner tip because of reduced amount of heat reflection to the burner tip compared to an annular barrier wall. The invention is particularly useful in furnaces where hydrogen-rich fuel gas is combusted.