Abstract: Methods and systems for producing a pressurized ammonia-containing gas stream from aqueous urea. The method comprising pumping an aqueous urea-containing solution to a fluid-tight enclosure at a rate to match the external demand for ammonia-gas, wherein a fluid heat transfer medium is applied to the exterior of the fluid-tight enclosure to transfer heat to the aqueous urea-containing solution sufficient to hydrolyze the solution to an ammonia gaseous product. The systems comprise means for carrying out the methods.

Abstract: Methods and systems for producing a pressurized ammonia-containing gas stream from aqueous urea. The method comprising pumping an aqueous urea-containing solution to a fluid-tight enclosure at a rate to match the external demand for ammonia-gas, wherein a fluid heat transfer medium is applied to the exterior of the fluid-tight enclosure to transfer heat to the aqueous urea-containing solution sufficient to hydrolyze the solution to an ammonia gaseous product. The systems comprise means for carrying out the methods.

Abstract: In a process for producing ammonia from urea which process comprises: (a) heating a liquid phase reaction medium comprising an aqueous solution of urea, or a mixture of urea, containing biuret or ammonium carbamate on site, in a hydrolysis reactor such that a pressurized gaseous ammonia and carbon dioxide-containing product is obtained which is essentially free of urea, biuret, or ammonium carbamate; (b) separating the gaseous ammonia and carbon dioxide-containing product from the liquid phase reaction medium at the prevailing pressure; (c) retaining the liquid phase reaction medium in the reactor for further conversion to gaseous ammonia and carbon dioxide, and/or recycling at least a portion of the said reaction medium back into the reactor, a urea dissolver, or feed solution to the reactor for further conversion; and (d) withdrawing the gaseous ammonia and carbon dioxide-containing product separated in step (b) at a controlled rate to meet varying ammonia demand requirements; the improvement wherein th

Abstract: In a process for producing ammonia from urea which process comprises: (a) heating a liquid phase reaction medium comprising an aqueous solution of urea, or a mixture of urea, containing biuret or ammonium carbamate on site, in a hydrolysis reactor such that a pressurized gaseous ammonia and carbon dioxide-containing product is obtained which is essentially free of urea, biuret, or ammonium carbamate; (b) separating the gaseous ammonia and carbon dioxide-containing product from the liquid phase reaction medium at the prevailing pressure; (c) retaining the liquid phase reaction medium in the reactor for further conversion to gaseous ammonia and carbon dioxide, and/or recycling at least a portion of the said reaction medium back into the reactor, a urea dissolver, or feed solution to the reactor for further conversion; and (d) withdrawing the gaseous ammonia and carbon dioxide-containing product separated in step (b) at a controlled rate to meet varying ammonia demand requirements; the improvement wherein th

Abstract: In a process for generating ammonia from urea which process comprises: (a) heating an aqueous solution of urea, or a mixture of urea, containing biuret or ammonium carbamate on site, in a hydrolysis reactor such that a gaseous ammonia-containing product is obtained which is essentially free of urea, biuret, or ammonium carbamate, the temperature and pressure being maintained by the input of heat to the reactor; (b) separating the gaseous ammonia-containing product from the liquid phase aqueous reaction media at the operating pressure; (c) retaining the liquid phase reaction medium in the reactor for further conversion to gaseous ammonia and carbon dioxide, and/or recycling at least a portion of the said reaction medium back into the reactor, a urea dissolver, or the feed solution to the reactor for further conversion; and (d) withdrawing the gaseous ammonia and carbon dioxide-containing product separated in step (b) at a controlled rate to meet demand requirements; the improvement wherein the temperature

Abstract: A system for preconditioning flue gas to be treated in an electrostatic precipitator having a set of electrostatic elements and a power supply, which supplies an intermittent power to the electrostatic elements, includes a source of a conditioning agent, and a current sensor and a voltage sensor for detecting the half-cycle current and voltage supplied to the electrostatic elements. The system also includes a power measuring circuit, responsive to the current sensor and to the voltage sensor, which develops an indication of the power supplied to the electrostatic elements and a controller, responsive to the power indication, which controls the amount of conditioning agent added to the flue gas in order to maintain the power at a substantially predetermined level.

Abstract: A method is used for preconditioning flue gas to be treated in an electrostatic precipitator having a set of electrostatic elements which are intermittently energized by a power supply. The method uses a current sensor and a voltage sensor to detect the current and the voltage supplied to the electrostatic elements during an energized half-cycle of the power delivered to the electrostatic precipitator and develops an indication of the intermittent power supplied to the electrostatic elements from the current and voltage sensor measurements. The amount of a conditioning agent added to the flue gas is controlled to maintain the power indication at a substantially predetermined level.

Abstract: A method for conditioning flue gas to improve the removal of fly ash by an electrostatic precipitator employs a relatively high concentration (4-71/2%) of SO.sub.3 conditioning agent. The SO.sub.3 is formed by combusting sulfur and excess air in a sulfur burner to produce a mixture of air and SO.sub.2 and converting the SO.sub.2 to SO.sub.3 in a catalytic converter. The ratio of air to sulfur is maintained constant over a wide range of SO.sub.3 production rates, and the air is unheated during most production rates. The mixture of air and SO.sub.2 from the sulfur burner is cooled without increasing the volume of the gaseous mixture.