Retrofitting micro gas turbines for wet operation. A way to increase operational flexibility in distributed CHP plants

Micro Gas Turbine Cycle Humidification for Increased Flexibility: Numerical and Experimental Validation of Different Steam Injection Models

“…Delattin et al also numerically studied the potential of auto-raised steam injection in the compressor outlet of a Turbec T100, showing that with a maximal injection of 3.3 % steam, the electrical efficiency increased by 5.1 % relative [3]. These numerical results were also obtained by Stathopoulos and Paschereit when simulating steam injection in the same mGT [11] and were finally validated experimentally by De Paepe et al [12,13]. Dur-ing these experiments, an increasing steam flow rate-provided by an external electric boiler-could be injected up to the thermodynamic limit for auto-raised steam, resulting in stable operation at constant power output and Turbine Outlet Temperature (TOT), increased electrical efficiency (5.6 % relative increase when 3.5 % of the air mass flow is replaced with steam) and reduced rotational speed.…”

“…Next to the effects of steam injection on the thermal performance of the mGT, several studies have also been published on the economical aspects [3,16,11,17]. Delattin et al presented the first preliminary analysis of the conversion of a T100 into a STeam-Injected Gas turbine (STIG) proving that at least 5000 hours of dry operation and a minimum of 1500 hours of wet operation are necessary to make steam injection profitable and favourable over the dry mGT [3].…”

“…Finally, the most in-depth economic analysis of the STIG mode on mGTs has been performed by Stathopoulos and Paschereit on a retrofit of a T100 mGT for the German CHP market. They showed that the retrofitted turbine has longer annual operation time and higher electrical energy generation, while it is also an attractive investment for the German CHP market with internal rates of return reaching almost 20 % [11,17].…”

“…The pre-heated air is sent to the combustion chamber where fuel is injected at 6 bar. As mentioned before, several works in literature report that the thermodynamic efficiency can be maximized by introducing steam upstream the recuperator [11,12]; however, the fuel required to run the mGT in STIG configuration becomes much higher causing the risk of reaching very high operating temperatures in the combustion chamber, which could facilitate the formation of pollutants. A proper injection of steam in specific zones of the combustion chamber should allow reducing the combustion temperature and the formation of CO and NO x [6].…”

Development of an ICE-Based Micro-CHP System Based on a Stirling Engine; Methodology for a Comparative Study of its Performance and Sensitivity Analysis in Recreational Sailing Boats in Different European Climates

“…A sensitivity analysis is performed in [31] to estimate the influence of the fuel and electricity prices on the profitability of a micro CHP unit. In [32] a sensitivity analysis of the major economic parameters was performed, focusing on the operational flexibility of the system. An optimization model for the capacity of distributed generation based on micro-CHP units is also presented in [33], where an interesting sensitivity analysis of costs was performed.…”