Abstract:
The invention relates to a method of making a mineral melt, the method comprising providing a circulating combustion chamber which comprises an upper zone, a lower zone and a base zone, injecting primary particulate fuel and particulate mineral material and primary combustion gas into the upper zone of the circulating combustion chamber, thereby at least partially combusting the primary particulate fuel and thereby melting the particulate mineral material to form a mineral melt and generating exhaust gases, injecting into the lower zone of the circulating combustion chamber, through at least one first burner, secondary combustion gas and gaseous fuel and secondary particulate fuel, wherein the secondary combustion gas and gaseous fuel and secondary particulate fuel are injected via a single first burner, wherein the amount of secondary combustion gas injected via each first burner is insufficient for stoichiometric combustion of the total amount of gaseous fuel and secondary particulate fuel injected via that first burner, and injecting tertiary combustion gas into the lower zone of the circulating combustion chamber, through at least one tertiary combustion gas injector, whereby the tertiary combustion gas enables completion of the combustion of the gaseous fuel and the secondary particulate fuel, separating the mineral melt from the hot exhaust gases so that the hot exhaust gases pass through an outlet in the circulating combustion chamber and the mineral melt collects in the base zone. The invention also relates to apparatus suitable for use in the method.
Abstract:
A furnace (10), firing pattern and method of operating a heater that employs a combination of hearth burners (46) and wall burners (56) for the cracking of hydrocarbons is described. The firing pattern leads to improvements in the uniformity of the coil metal (26) temperatures and vertical heat flux profiles over the firebox elevation. The hearth burners (46) operate with a stoichiometric excess of air while the wall burners (56) operate with less than the stoichiometric amount of air.
Abstract:
A furnace (10), firing pattern and method of operating a heater that employs a combination of hearth burners (46) and wall burners (56) for the cracking of hydrocarbons is described. The firing pattern leads to improvements in the uniformity of the coil metal (26) temperatures and vertical heat flux profiles over the firebox elevation. The hearth burners (46) operate with a stoichiometric excess of air while the wall burners (56) operate with less than the stoichiometric amount of air.
Abstract:
Emissions of NOx and CO are reduced from combustion devices such as coal-fired furnaces by increasing the stoichiometric ratio of burner (s) (30) having a lower average temperature and increasing the stoichiometric ratio of burner (s) (30) having a higher average temperature.
Abstract:
The present invention is related to methods and systems for preventing the release of nitrogen oxides with combustion flue gases emitted to the atmosphere. The invention is specifically directed to the removal of nitric oxide, nitrogen dioxide, and nitrous oxide from flue gas in stationary combustion systems. The methods of the invention improve efficiency of conventional reburning and advanced reburning processes by two key improvements, including the injection of a reducing agent into the reburning zone (16) and the use of promoters, which considerably enhance NOx control. The promoters are metal-containing compounds that can be added to the reducing agents. These improvements allow either one or two stages of reducing agent injection for greater NOx control (50).