Turbine Inlet Conditions Research Articles

Design and Off-Design Characteristics of the Alternative Recuperated Gas Turbine Cycle With Divided Turbine Expansion

In order to fully address the characteristics of the alternative recuperated cycle with divided turbine expansion, both design and off-design analyses have been performed. Two types of mechanical design are assumed: two shaft and single shaft. In particular, optimal pressure ratio division between the high- and low-pressure turbines is evaluated for the single-shaft configuration. It is predicted that the alternative recuperated cycle hardly exhibits sensible design efficiency advantage over the conventional recuperated cycle for moderate turbine inlet conditions and with usual component performances. An advantage of the alternative cycle with single-shaft design is that thermal efficiency is less sensitive to compressor pressure ratio compared to other configurations, and we can also have flexibility in the turbine division without much efficiency loss. The part load analyses have been carried out with the aid of realistic component maps and models for off-design operation. In addition to the general fuel only control, a variable speed control is assumed as the part load operating strategy of the single-shaft configuration. Obvious advantage with the alternative cycle is observed in the variable speed operation of the single-shaft design. With this strategy, the part load efficiency of the alternative cycle is far superior to the conventional cycle. Almost constant efficiency is predicted for a wide power range.

Cyclone gasifier and cyclone combustor for the use of biomass derived gas in the operation of a small gas turbine in cogeneration plants

An inverted cyclone gasifier and secondary cyclone combustor have been developed for use in a biomass fired small-scale cogeneration plant. The gasifier was designed with a vortex collector pocket (VCP) and a central collector pocket (CCP) to maximise particle and ash separation from the flow, and remove alkali and other heavy metal traces that agglomerate with the ash particles. The gasifier design was robust and suitable for firing with varying input conditions. The gasifier exhaust gas is suitable for directly firing into the secondary cyclone combustor without any complex hot gas clean up systems. The cyclone combustor produces a strong swirling flow with good mixing and burnout patterns, creating stable combustion conditions. The use of an additional VCP situated before the combustor exit removes the need for additional cyclone separators. An exhaust mounted tangential off-take on the combustor reduces pressure drop across the system and gives near uniform exhaust velocity profiles. The gasifier achieved 98–99% burnout with good separation/retention rates and 50% alkali, Na and K removal. A good quality low calorific value (LCV) gas was produced that could be effectively utilised in the cyclone combustor. The cyclone combustor produces a stable flow, with good mixing and burnout rates, and uniform exit conditions and could be operated in a lean mode to minimize NO x . The additional use of a VCP removed particles above 5 μm, as specified by turbine inlet conditions. The gas was suitable for directly firing into the gas turbine. Low pressure drop was found across the system.

Condenser optimization in steam power plant

In this paper the effects of the condenser design parameters (such as turbine inlet condition, turbine power and condenser pressure) on heat transfer area, cooling water flow-rate, condenser cost and specific energy generation cost are studied for surface type condenser. The results are given in the text and also shown as diagrams.

Superheated Steam Cycle for a D-D Tokamak

A relatively high temperature superheated steam cycle was designed to be compatible with a D-D tokamak blanket to help identify some of the benefits of using the D-D fuel cycle. Since less tritium leaves the plasma in a D-D reactor than in a D-T reactor and tritium is not produced in the D-D reactor blanket, it may be acceptable for steam generated in the first wall and blanket to be used directly in a turbine generator. Calculations indicated high temperature superheated steam (811K, 12.5MPa) could be generated within the allowable stresses of presently available piping materials./sup 1/ Based on these turbine inlet conditions, a backpressure of 50 mm HgA, 6-feedwater heaters, 1 reheater and a 6-flow cross compound turbine generator, the overall cycle efficiency is estimated to be 40.5%.