*Article* **A Detailed One-Dimensional Hydrodynamic and Kinetic Model for Sorption Enhanced Gasification**

#### **Marcel Beirow \*, Ashak Mahmud Parvez, Max Schmid and Günter Sche**ff**knecht**

University of Stuttgart, Institute of Combustion and Power Plant Technology (IFK), Pfaffenwaldring 23, 70569 Stuttgart, Germany; ashak.parvez@ifk.uni-stuttgart.de (A.M.P.); max.schmid@ifk.uni-stuttgart.de (M.S.); guenter.scheffknecht@ifk.uni-stuttgart.de (G.S.)

**\*** Correspondence: marcel.beirow@ifk.uni-stuttgart.de; Tel.: +49-0711-6856-8938

Received: 21 July 2020; Accepted: 27 August 2020; Published: 3 September 2020

**Abstract:** Increased installation of renewable electricity generators requires different technologies to compensate for the associated fast and high load gradients. In this work, sorption enhanced gasification (SEG) in a dual fluidized bed gasification system is considered as a promising and flexible technology for the tailored syngas production for use in chemical manufacturing or electricity generation. To study different operational strategies, as defined by gasification temperature or fuel input, a simulation model is developed. This model considers the hydrodynamics in a bubbling fluidized bed gasifier and the kinetics of gasification reactions and CO2 capture. The CO2 capture rate is defined by the number of carbonation/calcination cycles and the make-up of fresh limestone. A parametric study of the make-up flow rate (0.2, 6.6, and 15 kg/h) reveals its strong influence on the syngas composition, especially at low gasification temperatures (600–650 ◦C). Our results show good agreemen<sup>t</sup> with the experimental data of a 200 kW pilot plant, as demonstrated by deviations of syngas composition (5–34%), lower heating value (*LHV*) (5–7%), and *M* module (23–32%). Studying the fuel feeding rate (22–40 kg/h), an operational range with a good mixing of solids in the fluidized bed is identified. The achieved results are summarized in a reactor performance diagram, which gives the syngas power depending on the gasification temperature and the fuel feeding rate.

**Keywords:** one-dimensional SEG model; dual fluidized bed; sorbent deactivation; hydrodynamics; kinetics; fuel feeding rate; biomass
