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Reformer burners 1
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georgeverghese
Chemical
Wouldnt know about your first question, but to your second, Haldor Topsoe use radiant wall burners for minimum risk of flame impingement on radiant bank reformer tubes and better temp control over the tube length.
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georgeverghese
Chemical
Pictures of radiant wall burners can be seen on Google.
Good temp control is not only dependent on burner type. It is strongly influenced by catalyst activity in the case of endothermic reactions such as steam reforming of nat gas. If there is loss of activity due to catalyst pellet disintegration at some spots along the tube length, these will show up as hot spots.
Good temp control is not only dependent on burner type. It is strongly influenced by catalyst activity in the case of endothermic reactions such as steam reforming of nat gas. If there is loss of activity due to catalyst pellet disintegration at some spots along the tube length, these will show up as hot spots.
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Obviously, criterion for sustained and reliable fuel combustion in burner is air/fuel metering, mixing, ignition, shaping flame, stable short lame, emissions, (see “Burners for Reformers and Cracking”). The S-M Reformer burners are selected and located in line with the type of the heater and specific heating demands for endothermic catalytic reactions in light HCs in H2 conversio in the tubular reactor heater tubes. Flat flame has better tube coverage for side and against-wall firing, while round flame in between tubes in a top or bottom firing. No flame tube impingement is allowed.
Reformer operates at high temperatures for high H2 (min CH4 slip). Strong controlled temperature profile is necessary along the tube length to minimize thermal stress and creep damage. So, the burners arrangement and firing mode should produce in radiant box heat flux profile as flat as possible for tube temperature uniformity and long service life. Top-fired heater generates a sharp heat flux peak at first third of tube length, bottom at second, but side-fired and “terrace type” give flatter profile with small peaks. By flatting max heat flux in heater we increase avg. heat flux and tube temperature uniformly at high level (highest at tube exit) for driving desired reforming reactions toward end.
Catalyst aging or poisoning is compensated with more intensive firing and process and tube temperature increase to maintain high reaction rate. Designed burners type, number and capacity margin should allow it. Tube temperatures need strict monitoring by IR-camera and strong control below designed tube temperature to reach expected tube lifetime. Approaching the process end-of-run some tube discoloration could be visualized as bright spots demanding attention and adjustments in burner firing.
Reformer operates at high temperatures for high H2 (min CH4 slip). Strong controlled temperature profile is necessary along the tube length to minimize thermal stress and creep damage. So, the burners arrangement and firing mode should produce in radiant box heat flux profile as flat as possible for tube temperature uniformity and long service life. Top-fired heater generates a sharp heat flux peak at first third of tube length, bottom at second, but side-fired and “terrace type” give flatter profile with small peaks. By flatting max heat flux in heater we increase avg. heat flux and tube temperature uniformly at high level (highest at tube exit) for driving desired reforming reactions toward end.
Catalyst aging or poisoning is compensated with more intensive firing and process and tube temperature increase to maintain high reaction rate. Designed burners type, number and capacity margin should allow it. Tube temperatures need strict monitoring by IR-camera and strong control below designed tube temperature to reach expected tube lifetime. Approaching the process end-of-run some tube discoloration could be visualized as bright spots demanding attention and adjustments in burner firing.
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