Tham khảo tài liệu 'gas turbine engineering handbook 2 episode 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Theoretical and Actual Cycle Analysis 85 Figure 2-26. The Brayton-Rankine combined cycle. Overall cycle efficiency cyc 11 ritf LHV 2-41 This system as can be seen from Figure 2-27 indicates that the net work is about the same as one would expect in a steam injection cycle but the efficiencies are much higher. The disadvantages of this system are its high initial cost. However just as in the steam injection cycle the NOX content of its exhaust remains the same and is dependent on the gas turbine used. This system is being used widely because of its high efficiency. Summation of Cycle Analysis Figure 2-28 and 2-29 give a good comparison of the effect of the various cycles on the output work and thermal efficiency. The curves are drawn for a 86 Gas Turbine Engineering Handbook Figure 2-27. The performance map of a typical combined cycle power plant. Figure 2-28. Comparison of net work output of various cycles temperature. turbine inlet temperature of 2400 F 1316 C which is a temperature presently being used by manufacturers. The output work of the regenerative cycle is very similar to the output work of the simple cycle and the output work of the regenerative reheat cycle is very similar to that of the reheat cycle. The most work per pound of air can be expected from the intercooling regenerative reheat cycle. Theoretical and Actual Cycle Analysis 87 Figure 2-29. Comparison of thermal efficiency of various cycles temperature. The most effective cycle is the Brayton-Rankine cycle. This cycle has tremendous potential in power plants and in the process industries where steam turbines are in use in many areas. The initial cost of this system is high however in most cases where steam turbines are being used this initial cost can be greatly reduced. Regenerative cycles are popular because of the high cost of fuel. Care should be observed not to indiscriminately attach regenerators to existing units. The regenerator is most efficient at low-pressure ratios. Cleansing .
