An advanced syngas concept for the Siemens gasifier design was developed. A technical and thermodynamic comparison of different steam generator integration concepts was carried out. The most promising system variant was investigated in detail. Thus the basic and detailed engineering of the new large-scale gasifier plant and heat recovery system was realized. Theoretical analyses and studies for the gasifier island have been done, especially the investigation of the raw gas and ash properties for different load scenarios. Furthermore numerical simulations of the gas and slag flow were used to predict the operational behavior of the newly developed concept. Additionally, an economic evaluation, using the net present value method, was executed. The results and efficiency improvements were compared with Siemens standard design of an IGCC plant represented by the gasifier with full water quench. The selected concept shows an efficiency advantage for IGCC with CCS (Carbon Capture and Storage) of about 1.91% pt. and approx. 3% pt. for IGCC without CCS. (C) 2013 Elsevier Ltd. All rights reserved.