Investigation of the Gasification Performance of Lignite Feedstock and the Injection Design of a Cross-Type Two-Stage Gasifier

Abstract

In the last three years, the Institute of Nuclear Energy Research (INER) has been developing the E-GAS gasification numerical model and analyzing the gasification performance by conducting several parametric studies. A preliminary numerical model considering coal particles tracking, two-step volatiles thermal cracking, and nine chemical reactions has been established. In last year’s results, the single lateral injector design in the second stage of E-GAS gasifier is found nonideal for the gasification process. Therefore, one of the objectives in this study is to modify the second stage injection and investigate its effect on gasification performance. Moreover, because of rising interest in the use of low-rank coals as the feedstock for power plants, the second goal in this paper is to investigate the gasification features by using North Dakota (ND) lignite as the feedstock. The result shows that a dual-injector design (either tangential or opposing jets) in the second stage injection of E-GAS gasifier can minimize the nonideal recirculation zone and improve the gasification performance. Furthermore, a tangential injection design can make the average temperature reach equilibrium more quickly, so the height of the E-GAS gasifier could therefore be shortened. Moreover, by examining the energy needed for the second stage injection, a tangential injection design saves more energy as compared to the opposing-jets design. The result of the assessment of ND lignite shows that under the same condition of O2/coal and coal/slurry ratios, no matter what the feedstock flow rate or the total input heating value, the gasification performance of ND lignite is always lower than that of Illinois #6 coal. However, the cheaper price of ND lignite makes it more competitive, and if the electricity generating industries can accept a lower gasification performance, the usage of ND lignite can be a choice to be considered.

Simulation of Coal Gasification in a Low-Temperature, High-Pressure Entrained-Bed Reactor with a Volatiles Condensation and Re-Evaporation Model

“…A mathematical model was developed by Wen et al in 1979 [5], to investigate the influence of input operating parameters for the Texaco (Now, GE) down-draft entrainment pilot plant gasifier. Furthermore, the gasification process and its performance have been studied comprehensively by CFD modeling for several years [4,[6][7][8][9][10][11][12][13][14][15][16][17]. Chen et al [18] developed a numerical model to investigate a 200-ton, two-stage air-blown entrained type gasifier for an IGCC process.…”

“…In our previous studies [2,4], the E-Gas TM gasifier has been investigated and results have been compared with the reports issued by the Department of Energy/National Energy Technology Laboratory (DOE/NETL). After the model validation, the effects of the 2nd stage injection mode as well as the feedstock type were investigated comprehensively [4]. It is more productive to continue follow-up studies of the new product derived from E-Gas TM gasifier.…”

Thermodynamic evaluation of integrated gasification combined cycle: Comparison between high-ash and low-ash coals

“…In this study, the coal exists in the Tabas region of Iran, and Illinois #6 coal is chosen as low and high‐heating value coals, respectively. Table shows the proximate and ultimate analyses of these coals .…”

“…In this study, the coal exists in the Tabas region of Iran, and Illinois #6 coal is chosen as low and high-heating value coals, respectively. Table I shows the proximate and ultimate analyses of these coals [5,32]. According to Table I, Tabas coal contains more than 30% ash, which is much higher than the conventional coal, such as Illinois coal by 9.7% [33].…”

“…Specification of coals[5,32].Thermodynamic analysis of IGCC: A comparison of low and high-ash coals A. Arabkhalaj, H. Ghassemi and R. Shahsavan Markadeh…”