Abstract: In a nozzle and a nozzle assembly, for use in a pressure vessel, stress analysis is used to determine areas of stress concentration. The nozzle is configured to reduce these stress concentrations.

Abstract: An evaporator 10 for evaporating a liquid includes a plurality of harps 20 disposed within a duct or chamber such that a heated fluid flow 22 (e.g., heated gas or flue gas) passes through each successive row of harps 20 of the evaporator 10. Each of the harps 20 includes a lower header 24, a plurality of lower tubes 26, an intermediate equalizing chamber 28, a plurality of upper tubes 30, and an upper header 32. The lower tubes 30 are in fluid communication with the lower header 24 and extend upward vertically from the lower header. The upper ends of the lower tubes 26 are in fluid communication with the equalizing chamber 28. The upper tubes 30 are in fluid communication with the equalizing chamber 28 and extend upward vertically from the equalizing chamber. The upper ends of the upper tubes 30 are in fluid communication with the upper header 32.

Abstract: A heat recovery steam generator that includes a first steam drum for receiving a flow of water and steam from an evaporator. The first steam drum is adapted to provide the flow of water and steam to a second steam drum. The second steam drum is in fluid communication with the first steam drum and receives the flow of water and steam from the first steam drum and separates steam from the flow of water and steam to form a separated steam. There is a steam flow outlet positioned in the second steam drum, the steam flow outlet adapted to release the separated steam from the second steam drum.

Abstract: In a nozzle and a nozzle assembly, for use in a pressure vessel, stress analysis is used to determine areas of stress concentration. The nozzle is configured to reduce these stress concentrations.

Abstract: An evaporator system comprises an evaporator; a drum; and a pump that are in fluid communication with each other. The pump is operative to create a temporary pressure gradient during start-up of an evaporator system and transport a fluid from the evaporator to the drum prior to the fluid reaching its boiling point in the evaporator. Following the fluid reaching its boiling point in the evaporator, the fluid naturally circulates in the evaporator system.

Abstract: A heat recovery steam generator that includes a first steam drum for receiving a flow of water and steam from an evaporator. The first steam drum is adapted to provide the flow of water and steam to a second steam drum. The second steam drum is in fluid communication with the first steam drum and receives the flow of water and steam from the first steam drum and separates steam from the flow of water and steam to form a separated steam. There is a steam flow outlet positioned in the second steam drum, the steam flow outlet adapted to release the separated steam from the second steam drum.

Abstract: A method of controlling stress in a boiler pressure vessel comprises limiting the diameter of a drum (10) of the boiler pressure vessel and preheating at least a portion of the wall (12) of the drum (10). Limiting the diameter of the drum (10) allows pressure in the drum (10) to be increased for a given mechanical stress. Furthermore, preheating the wall (12) of the drum (10) reduces peak thermally induced stresses in a material from which the drum (10) is fabricated.

Abstract: An evaporator 10 for evaporating a liquid includes a plurality of harps 20 disposed within a duct or chamber such that a heated fluid flow 22 (e.g., heated gas or flue gas) passes through each successive row of harps 20 of the evaporator 10. Each of the harps 20 includes a lower header 24, a plurality of lower tubes 26, an intermediate equalizing chamber 28, a plurality of upper tubes 30, and an upper header 32. The lower tubes 30 are in fluid communication with the lower header 24 and extend upward vertically from the lower header. The upper ends of the lower tubes 26 are in fluid communication with the equalizing chamber 28. The upper tubes 30 are in fluid communication with the equalizing chamber 28 and extend upward vertically from the equalizing chamber. The upper ends of the upper tubes 30 are in fluid communication with the upper header 32.

Abstract: The water flow circuit for a heat recovery steam generator is a hybrid system which combines a circulating drum type circuit and a once-through circuit. A low pressure evaporator is designed for natural or forced circulation and a high pressure evaporator is designed for once-through flow. Orifices may be located in the inlet of the evaporator tubes for flow stability and an intermediate header between the evaporator and high pressure superheater improves stability, minimizes orifice pressure drop and equalizes pressure losses between evaporator tubes.