Reduced order modeling of the Shell–Prenflo entrained flow gasifier

Abstract

Pre-combustion capture applied to an Integrated Gasification Combined Cycle is a promising solution for greenhouse gas emission's mitigation. For optimal design and operation of this cycle, detailed simulation of entrained flow gasifiers and their integration in the flowsheet analysis is required. This paper describes the development of a Reduced Order Model (ROM) for the ShellPrenflo gasifier family, used for chemicals and power production because of its high efficiency and compatibility with a wide range of coal quality. Different from CFD analysis, ROM is computationally very efficient, taking around 1 min in a typical desktop or laptop computer, hence enabling the integration of the gasifier model and the overall power plant flowsheet simulation. Because of the gasifier complexity, which includes several gas recirculation loops and a membrane wall, particular attention is paid to: (i) the two-phase heat exchange process in the gasifier wall; and, (ii) the syngas quench process. Computed temperature, composition, velocity and reaction rate profiles inside the gasifier show good agreement with available data. The calculated Cold Gas Efficiency is 82.5%, close to the given value of 82.8%. Results and several sensitivity analyses describe the implementation of the model to explore the potential for operating gasifiers beyond the design point.

Techno-economic assessment of two novel feeding systems for a dry-feed gasifier in an IGCC plant with Pd-membranes for CO2 capture

“…From a simulation point of view, the first option is suitable when using a kinetic model (ROM or CFD) while the second one fits well the equilibrium approach, where the equilibrium temperature must be set in order to fairly reproduce a reference syngas composition. Consistent with the results shown in (Gazzani et al, 2013b), the first method was adopted in this work. In both cases the amount of CO 2 required is defined by keeping the overall volumetric flow at the lockhopper system constant.…”

“…On the other hand, given that use of CO 2 as coal carrier has only been proposed recently, no experimental data are available. In this study, the kinetic model presented in (Gazzani et al, 2013b) has been used to predict the syngas composition along the entire process. The amount of gas needed for candle filters backflushing and coal feeding have been updated according to the most recent data (Prins, 2012).…”

“…the nitrogen based, the CO 2 based and the hybrid layout. The reported data were obtained using the kinetics-based reduced order model presented and validated in (Gazzani et al, 2013b). The gasifier island layout (comprising: ASU and its compressors, gasifier reactor, syngas cooler, lockhopper system, candle filters, wet scrubber and water treatment) for the cases in which: (a) CO 2 (in green) is adopted both as fuel carrier and candle filters purge gas and, (b) nitrogen is used to charge the coal while CO 2 purifies the candle filters.…”

“…The overall plant, equilibrium-based, model was calibrated in order to provide the same syngas composition and auxiliaries consumption provided by the kinetics reduced-order model of the gasifier (Gazzani et al, 2013b). In all cases, due to the low membrane tolerance to sulfur (i.e.…”

“…In coal-based plants, as assumed in this work, the pre-combustion technology fits perfectly into Integrated Gasification Combined Cycles (IGCC). IGCC consists of a high pressure reactor which converts coal into syngas; the gasification pressure depends on the technology: the Shell-Prenflo dry-fed gasifier works near 40 bar (Franco et al, 2011(Franco et al, , 2010Gazzani et al, 2013b), while the GE's slurry fed technology at 70 bar (DOE/NETL-2011/1498, n.d.). The produced syngas can then be utilized in a combined cycle.…”