API RP 669 pdf download Heat Recovery Systems
1.1 This recommended practice (RP) provides guidelines for heat transfer equipment used in waste heatrecovery systems in the petroleum,petrochemical, and natural gas industries. Details of related equipmentdesigns are included only where these are necessary to ensure proper design and operation and safe interactionwith the heat recovery system. lt indicates areas that need attention and offers information and descriptions ofvarious types of heat transfer equipment available to aid in the selection of the appropriate heat recovery system.1.2This RP does not include detailed requirements for:
-process to process heat recovery systems,
-gas turbine exhaust heat recovery,- cO boilers, or
– convection sections used within fired heaters.
1.3The waste heat recovery systems included in this RP are typical of those currently in use and should notlimit the use of alternate systems.
1.4Instrumentation and controls for waste heat recovery systems are sometimes mentioned but is not meant tocompletely define all requirements. Other standards and documents, such as APl Recommended Practice 556,Instrumentation, Control, and Protective Systems for Fired Heaters, should be used to fully define the neededinstruments and controls.
There are no normative references in this document.
3Terms, Definitions,Acronyms, and Abbreviations
For the purposes of this document, the following terms and definitions apply.
The difference between the saturation temperature of the steam at the selected pressure and the temperature ofthe water leaving the economizer.
A device located internal or external to the HRSG that controls the exit temperature of the steam from thesuperheater. The device typically injects water with very low solids content into the steam to control the steamtemperature by reducing it.Also called an attemperator.
Aheated or unheated pipe carrying water from the steam drum to an evaporatorlgenerator section of anHRSG.
The portion of the HRSG in which water is boiling to form steam. Typically, a mixture of water and steam existsat the exit of this portion. In some configurations, the steam and water are separated prior to leaving this portionof the HRSG.Also referred to as a steam generator section.
The portion of the HRSG where incoming feedwater temperature is raised to less than saturation temperature byrecovery of the heat from the heating medium.
A high temperature resistant metallic or ceramic shaped tube insert provided at the tube and tubesheet area toinsulate components from high temperatures and to limit heat transfer.
A shell-and-tube heat exchanger in which steam is generated on the shell side by heat transferred from hot fluidflowing through the tubes.
heat recovery steam generator(HRSG)
A system in which steam is generated and may be superheated or water heated by the transfer from heatmedium usually gaseous products of combustion or other hot process fluids.
heat recovery system
A system that transfers energy from one medium to a second medium for reuse.
The difference between the heating medium temperature leaving the steam generator section and the steam’ssaturation temperature at the selected pressure.
The heating medium used to supply the heat to the utility fluid.
A heated or unheated pipe carrying water and steam from an evaporatorlgenerator section of an HRSG to thesteam drum.
shell-and-tube watertube HRSG
Ashell-and-tube heat exchanger in which steam is generated in the tubes by heat transferred from a hot fluid onthe shell side.