A boiler system comprises a housing with a generally cylindrical shape extends between first and second walls to provide a generally cylindrical space. A fire tube is positioned near a bottom of the generally cylindrical housing and extends longitudinally from a first wall of the cylindrical housing to a fire tube end wall. The boiler system also includes a burner with a generally cylindrical housing which defines a generally cylindrical chamber and an end plate. The burner extends into the fire tube, and the fire tube provides a combustion chamber where combustion of an air-fuel mixture is accomplished using the burner. The end plate of the burner is adjustable so as to adjust the flame that extends from within the burner housing into the fire tube.

A boiler system comprises a housing with a generally cylindrical shape extends between first and second walls to provide a generally cylindrical space. A fire tube is positioned near a bottom of the generally cylindrical housing and extends longitudinally from a first wall of the cylindrical housing to a fire tube end wall. The boiler system also includes a burner with a generally cylindrical housing which defines a generally cylindrical chamber and an end plate. The burner extends into the fire tube, and the fire tube provides a combustion chamber where combustion of an air-fuel mixture is accomplished using the burner. The end plate of the burner is adjustable so as to adjust the flame that extends from within the burner housing into the fire tube.

A fire tube with three hollow tube sections, two of which are parallel to each other and one of which is perpendicular to and connects the ends of the first two tube sections. The bottom-most tube section, which contains the burner, has an inner ceramic liner that is made up of one or more separate ceramic tubular sections. An upper set of cooling funs surrounds the top part of the bottom-most tube section, and a lower set of cooling fins surrounds the bottom part of the bottom-most tube section.

A fire tube with three hollow tube sections, two of which are parallel to each other and one of which is perpendicular to and connects the ends of the first two tube sections. The bottom-most tube section, which contains the burner, has an inner ceramic liner that is made up of one or more separate ceramic tubular sections. An upper set of cooling funs surrounds the top part of the bottom-most tube section, and a lower set of cooling fins surrounds the bottom part of the bottom-most tube section.

The current invention disclose a method and apparatus for production of hot water or steam in a firetube boiler, said method comprising the steps of producing a first flue gas using a first stage of a burner in a first pass of a firetube boiler; passing at least a portion of said first flue gas through a second pass of said boiler, wherein said second pass comprises a plurality of firetubes; routing said portion of said first flue gas to a second stage of said burner to reduce NOx emissions from said second stage of said burner; producing a second flue gas from said second stage of said burner in a third pass of said boiler; passing said second flue gas through a fourth pass of said boiler, wherein said fourth pass comprises a plurality of firetubes.

The current invention disclose a method and apparatus for production of hot water or steam in a firetube boiler, said method comprising the steps of producing a first flue gas using a first stage of a burner in a first pass of a firetube boiler; passing at least a portion of said first flue gas through a second pass of said boiler, wherein said second pass comprises a plurality of firetubes; routing said portion of said first flue gas to a second stage of said burner to reduce NOx emissions from said second stage of said burner; producing a second flue gas from said second stage of said burner in a third pass of said boiler; passing said second flue gas through a fourth pass of said boiler, wherein said fourth pass comprises a plurality of firetubes.

A boiler system comprises a housing with a generally cylindrical shape extends between first and second walls to provide a generally cylindrical space. A fire tube is positioned near a bottom of the generally cylindrical housing and extends longitudinally from a first wall of the cylindrical housing to a fire tube end wall. The boiler system also includes a burner with a generally cylindrical housing which defines a generally cylindrical chamber and an end plate. The burner extends into the fire tube, and the fire tube provides a combustion chamber where combustion of an air-fuel mixture is accomplished using the burner. The end plate of the burner is adjustable so as to adjust the flame that extends from within the burner housing into the fire tube.

A boiler system comprises a housing with a generally cylindrical shape extends between first and second walls to provide a generally cylindrical space. A fire tube is positioned near a bottom of the generally cylindrical housing and extends longitudinally from a first wall of the cylindrical housing to a fire tube end wall. The boiler system also includes a burner with a generally cylindrical housing which defines a generally cylindrical chamber and an end plate. The burner extends into the fire tube, and the fire tube provides a combustion chamber where combustion of an air-fuel mixture is accomplished using the burner. The end plate of the burner is adjustable so as to adjust the flame that extends from within the burner housing into the fire tube.

A boiler system comprises a housing with a generally cylindrical shape extends between first and second walls to provide a generally cylindrical space. A fire tube is positioned near a bottom of the generally cylindrical housing and extends longitudinally from a first wall of the cylindrical housing to a fire tube end wall. The boiler system also includes a burner with a generally cylindrical housing which defines a generally cylindrical chamber and an end plate. The burner extends into the fire tube, and the fire tube provides a combustion chamber where combustion of an air-fuel mixture is accomplished using the burner. The end plate of the burner is adjustable so as to adjust the flame that extends from within the burner housing into the fire tube.

A boiler system comprises a housing with a generally cylindrical shape extends between first and second walls to provide a generally cylindrical space. A fire tube is positioned near a bottom of the generally cylindrical housing and extends longitudinally from a first wall of the cylindrical housing to a fire tube end wall. The boiler system also includes a burner with a generally cylindrical housing which defines a generally cylindrical chamber and an end plate. The burner extends into the fire tube, and the fire tube provides a combustion chamber where combustion of an air-fuel mixture is accomplished using the burner. The end plate of the burner is adjustable so as to adjust the flame that extends from within the burner housing into the fire tube.