Power recovery turbine

Development The following discussion relates specifically to the use of what could be called radial-inflow, centrifugal-pump power-recovery turbines. It does not apply to the type of unit nurtured by the hydroelecti ic industry for the 1 ge-horsepower, large-flow, low- to medium-pressure differential area of hydraulic water turbines of the Felton or Francis runner type. There seems to have been little direct transfer of design concepts between these two fields the major manufacturers in the hydroelectric field have thus far made no effort to sell to the process industries, and the physical arrangement of their units, developed from the requirements of the hydroelectric field, is not suitable to most process-plant applications. 

FIG. 29-52 Generalized curves showing hydraulic behavior of centrifugal pumps operating as power-recovery turbines. 

FIG. 29-56 Flow diagram of a system with a power-recovery turbine operating with a makeup driver. 

FIG. 29-58 Head-horsepower-capacity characteristics of a lean pump tandem-connected with a power-recovery turbine operating as the sole driver. To convert gallons per minute to cubic meters per minute, multiply by 3.79 X 10 to convert horsepower to kilowatts, multiply by 0.746 and to convert pounds-force per square inch to megapascals, multiply by 6.89 X 10 . ... 

FIG. 29-59 Head-horsepower-capacity characteristics of a power-recovery turbine operating as the sole driver of a lean pump. If the total capacity of lean and semilean pumps exceeds the values indicated by available head limit, bypass must be used. Net recovery-pump head at 8.71 mVmin (2300 gal/min) is figured as follows ... 

Typical chemical analysis of some alloys used in power recovery turbines... 

TTiere are two main types of expansion turbines axial flow and radial flow. Axial flow expansion turbines are like conventional steam turbines. They may be single-stage or multistage with impulse or reaction blading, or some combination of the two. Turbines of this type are used as power recovery turbines. They are used where flow rates, inlet temperatures, or total energy drops are very high. 

Figure 7-22. FCC power recovery turbine. (Courtesy of Elliott Company)...

Heat recovery tor steam generation, pre-heating combustion air, and high efficiency burners Adjustable speed drives, heat recovery coke oven gases, and dry coke quenching Efficient hot blast stove operation, waste heat recovery for hot blast stove, top gas power recovery turbines, direct coal injection... 

This standard covers the minimum requirements for centrifugal pumps, including pumps running in reverse as hydraulic power recovery turbines, for use in petroleum, heavy duty chemical, and gas industry services. 

This appendix applies to reverse-running hydraulie power recovery turbines (HPRTs) used in the petroleum industry. 

Note When hydraulic power recovery turbines are operated at rated speed, they should achieve their rated power output and rated differential head at a flow within 5 percent of rated flow. 

Annex C specifies requirements for hydraulic power recovery turbines. 

Power recovery is generally achieved by the reduction of fluid pressure, sometimes with a contribution from vapour or gas evolution during the pressure reduction. A hydraulic power recovery turbine may be a pump operated with reverse flow. 

The stripped catalyst gravitates through a short standpipe into a single vessel, simple, reliable and yet efficient catalyst regenerator. Regenerative flue gas passes via a cyclone/swirl tube combination to a power recovery turbine. From the expander turbine the heat in the flue gas is further recovered in a waste heat boiler. 

Power recovery turbines, which let down suitable refrigerants under pressure, are also being developed (2). In conjunction with absorption refrigeration, these could be used to recover power from compressor coolers and other low grade heat. 

POWER RECOVERY TURBINES ON HIGH PRESSURE REFINERY PROCESS FLOW STREAMS 11.0 MW electricity for 100,000 bbl/day ref inery 2.8 x 106 8.2 x 109 per Quad of electricity 8 Times Conservation... 

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