Investigation into the operation of an autothermal two-section subbituminous coal fluidized bed gasifier

Abstract

Using a newly developed experimental setup, the features and advantages of an autothermal single-casing atmospheric subbituminous coal fluidized bed air-blown gasifier, combining a combustion and gasification section, and mixing the dispersed phase (inert material, char) and heat exchange between them through an annular transfer device, have been revealed. To increase the efficiency of the gasifier, an experimental-computational method was developed find the conditions for optimal operation, combining changing the annular flow’s geometry and regulating the primary air for gasification. A simple and reliable multizone thermodynamic calculation model makes it possible to predict the composition of char and syngas in the gasification section with acceptable accuracy. This method confirmed that a two-section fluidized bed gasifier can provide efficient gasification of solid fuels and is suitable for use in small-scale cogeneration plants. Syngas with a heating value of 3.6–4.5 MJ/m3 and CGE of 38.2%–42.3% was obtained in the experimental setup without optimizing the primary air flow rate. With optimization, the indicators increased to the heating value of syngas of 5.20–5.34 MJ/m3 and CGE of 42.5%–50.0%. With heat regeneration of 0.8, CGE increases to 70%.

Fluid Dynamics Investigation in a Cold Flow Model of Internal Recycle Quadruple Fluidized Bed Coal Pyrolyzer

“…So far, the main types of pyrolysis reactors that have been developed include fixed bed [7][8][9], bubbling fluidized bed [10][11][12], circulating fluidized bed [13][14][15], entrained flow [16,17], etc. Among them, circulating fluidized bed shows technological and commercial superiority for coal pyrolysis due to short residence time, fast heat transfer, and fast separation of volatiles and char [18,19], although it has some disadvantages such as requiring more fuel conditioning and capital investment [20]. Inspired by the advantage of the circulating fluidized bed, the dual fluidized bed (DFB) conversion technologies are proposed, which have a characteristic of using two fluidized bed (FB) reactors that are interconnected with circulated heat carrier particles for higher heating rates [21][22][23][24][25][26][27][28].…”

“…In this work, an internal recycle quadruple fluidized bed pyrolyzer (IR-QFBP) was first proposed [20,33], and the scheme of IR-QFBP is shown in Figure 1. IR-QFBP is divided into two zones including a pyrolysis zone (two axisymmetric high-speed beds) and a combustion zone (two axisymmetric low-speed beds).…”

Energy Extraction and Processing Science

“…Zhang et al [19] reconstructed the micro fracturing structure of coal in the Surat Basin by employing the 3D shape measurement system and the stitching algorithm, then generated transparent models characterizing the fracturing structure using microfluids, and measured water invasion in the micro fracture model under different conditions through visual experiments. Abaimov et al [20] developed an experimental device based on the characteristics of underground coal-gasification engineering, and studied the characteristics and advantages of a self-heating single-set atmospheric-pressure bituminouscoal fluidized-bed air-blown gasifier. Zhang et al [21] conducted a cyclic triaxial loading and unloading (CTLU) experimental study on the acoustic emission monitoring of deep coal samples.…”