Shell Oil Comapny

Gregory L Johnson

William Larry Hamilton

Norman C Samish

Diana M Altrichter

Harry S Tang

The invention includes method and apparatus for controlling the stability of a burner, preferably a low NOburner, of a natural draft heater. The method includes measuring the draft over a time period and generating a measured output from which a draft function is determined that defines the relationship between the draft and time during the time period. A value for the burner stability is defined that is representative of a stable burner operation. The draft function is compared to the stable burner value to determine a differential value, and the operation of the fired heater is adjusted in response to the differential value. The apparatus includes means for measuring the draft over a time period and means for generating a measured output from which a draft function is determined that is proportional to the cyclic variation of the draft during the time period. Further included is means for comparing the draft function to a defined burner stability value representative of a stable burner operation to determine a differential value and means for adjusting the operation of the fired heater in response to the differential value.

Method and apparatus for monitoring and controlling the stability of a burner of a fired heater

A method is disclosed for reducing NOx pollutants in the combustion of hydrocarbon fuels in a two stage burner. A first stage of combustion is established and maintained passing a stream of combustion air and first stage products of combustion down a centerline of the burner to a second stage downstream therefrom. This second stage is established by arranging an array of fuel tips around the first stage burner, each fuel tip having a fuel jet with a nominal trajectory angled toward the burner centerline and an inert gas jet placed between the burner and the fuel jet which is angled to cross the trajectory of the fuel jet. Fuel is injected into the second stage of the burner through the fuel jet and the inert gas, e.g. steam, is injected through the inert gas jet such that it influences the trajectory of the fuel to a modified fuel trajectory which is moved away from the centerline of the burner. Controlling the injection of the inert gas as a function of the firing rate for the burner allows the modified fuel trajectory to be moved progressively outward from the centerline of the burner across a range of increasingly higher firing rates. This reduces NOx production by moving the introduction of second stage combustion to a cooler and less oxygen rich area of the furnace as the furnace is progressively fired to greater heat outputs. Another aspect of the present invention is a low NOx burner.

System and method for reduced NOx combustion

A method is disclosed for the addition of an oxygen-containing gas under certain defined process conditions, to an off-gas stream derived from an FCC regenerator which is operated in a partial mode of combustion. The off-gas from the regenerator contains 1-6% CO by volume and at least 300 ppm nitrogen compounds comprising NH.sub.3 and HCN. Without the addition of an oxygen-containing gas, roughly 25 percent of the NH.sub.3 and HCN are converted to NO.sub.x in downstream CO boilers. A preferable method of this invention comprises the addition of heated air (20% O.sub.2) into the regenerator off gas to produce an off gas stream having a temperature of 1260.degree. F. to 1500.degree. F.

Method of removing NH.sub.3 and HCN from and FCC regenerator off gas

A novel fuel burner is disclosed for the combustion of fuel in the presence of flue gas and water added to the nozzle tip in a liquid phase through a water outlet means at the nozzle. Steam is used as an indirect heat exchange fluid to cool the steam to water (used in the combustion) and to heat the flue gas passed to the burner. The orifices of the water outlet means are configured to insure a sufficient amount of water flow to reduce NO.sub.x (by increasing the amount of flue gas) and to insure that the flame of the burner is not extinguished.

Low NO.sub.x burner

The invention is a process for combusting a gaseous fuel in a burner to result in low NO.sub.x emissions by first feeding a gaseous fuel stream and an air stream to a premixer where the fuel and air streams are mixed to form a fuel-air mixture. The fuel and air streams are fed to the premixer at a fuel to air equivalence ratio of less than 1 (i.e., fuel-lean). Second, the fuel-air mixture is passed to a combustion chamber where the fuel is substantially combusted to produce a combustion chamber jet and flue gases. The combustion chamber jet and flue gases pass into a heating zone which may include a furnace, heater, or boiler. Third, at least two high-velocity fuel streams, optionally diluted with a nonreactive thermal ballast, are passed to the heating zone contemporaneously with the second step. The high-velocity fuel streams entrain at least a portion of the flue gases. The fuel in the high-velocity fuel streams is partially combusted prior to coming into contact with the combustion chamber jet. Last, the flue gases are removed from the heating zone.

Premixed/high-velocity fuel jet low no burner

A regeneration zone for fluid catalytic cracking contains ammonia (NH.sub.3) when the regeneration zone is operated in a partial combustion mode as defined by a content of CO of between 1 and 6 percent by volume. If the ammonia is not removed from the regeneration zone off gass, the same will be passed to a CO combustion zone where, in the presence of oxygen, CO is oxidized to CO.sub.2 and some of the ammonia will undesirably be oxidized to NO.sub.x. This invention reduces the presence of ammonia in the feed gas to a CO combustion zone of an FCC process by the introduction of a NO.sub.x -containing gas to dilute phase of a regeneration zone or to a regeneration zone off gas. Ammonia, NO.sub.x and oxygen present in the regeneration zone off gas of the regeneration zone, will tend to react to produce nitrogen and water vapor, which then is passed to the CO combustion zone for CO oxidation to CO.sub.2. Where the addition of NO.sub.x is made at temperatures greater than 1700.degree. F., hydroxyl precursor addition may not be required. Where addition is made at temperatures lower than 1700.degree. F. a hydroxyl precursor may be added to the gas admixtures.

Process for the reduction of ammonia in regeneration zone off gas by

The present invention pertains to an oil atomizer suitable for use with a heavy liquid fuel which is constituted by a cylindrical body for delivery of the heavy liquid fuel to an atomization zone, spray tubes in the atomization zone arranged about the periphery of a conical cap terminating the cylindrical barrel and a shroud surrounding the cylindrical barrel and permitting passage therebetween and a shroud tip terminating the shroud and enclosing the cap, the spray tubes being inserted through openings in the shroud tip which permit passage of air or other fluid around the spray tubes.

Growing community of inventors

Houston, TX, United States of America

Gregory L Johnson