OCR Text |
Show Table 5. Candidate N O x controls Controls Water Injection (WI) Selective Catalytic Reduction (SCR) Dry Low-NO, Combustors (DLNC) Lean Bum (Spark/Prechamber) Nonselective Catalytic Reduction (NSCR) Prcstratified Charge (PSC) Field Adjustments and Minor Equip.Modifications Gas Turbines X X X Uncontrolled Two-Stroke Engines Naturally Aspirated X Turbo/ Supercharged X X X Uncontrolled Four Stroke Engines Naturally Aspirated X X X Turbocharged X X X X W l entails considerable expense for water treatment and increased turbine maintenance. Most W I systems, in addition, require an abundant supply of water. For remotely located compressor stations, access to large supplies of treatable water is often unavailable. Also, reliance on relatively unattended prime mover operation makes the increased equipment maintenance and control associated with W I infeasible for this population of gas turbines. Table 6 summarizes cost effectiveness estimates for W I on pipeline gas turbines. The cost effectiveness can be relatively large when accessability to treatable water and increased turbine maintenance are considered in the total cost. In summary, experience with W I for smaller, variable-load gas turbines is not available. Significant problems are anticipated because such units are not base-loaded and would be subject to transients that are damaging to major gas turbine components. Table 6. Summary of cost effectiveness for W I on a 3,300-bhp gas turbine Case Optimistic case (no turbine ware; water available) Average case (turbine ware; water available) Pipeline case (turbine ware; no water available) Source: Reference 2. Several scenar NOx Reduction From 0.52 to 0.15 lb/MMBtu $2,262 Scenario 1 $3,582 Scenario 4 $5,301 Scenario 7 ios are considered 0.40 to 0.15 lb/MMBtu $2,996 Scenario 2 $4,950 Scenario 5 $7,202 Scenario 8 because of uncertain 033 to 0.15 lb/MMBtu $3,782 Scenario 3 $6,495 Scenario 6 $9,313 Scenario 9 ties in baseline N O , levels, increased turbine wear, and availability of large quantities of treatable water. Gas turbine duty cycle 7,000 hrs/yr 7 1-4 |