Coal devolatilization during rapid transient heating. 2. Secondary pyrolysis

Chen, John C.; Castagnoli, Craig; Niksa, Stephen

doi:10.1021/ef00033a005

Cited by 114 publications

(97 citation statements)

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“…The heavy tar yield was lower with increasing pyrolyzer temperature. Secondary gas phase decomposition of tar derived from pyrolysis therefore occurred [23]. The heavy tar yield at each pyrolyzer temperature decreased with char recycling time.…”

Section: Reduction Of Light Tar With Char Recyclingmentioning

confidence: 99%

Reduction and Reforming of Tar with Enhanced Volatile-Char Interaction during Coal Pyrolysis

Kawabata¹,

Wajima²,

Nakagome³

et al. 2015

IJCEA

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Abstract-We attempted to reduce and reform tar-derived pyrolysis during coal gasification. Volatile-char contact can be used to reduce tar emissions. We developed a novel circulating fluidized bed consisting of a bubbling bed pyrolyzer and combustor made of quartz for direct observation of the solids' behavior. Raw coal was fed to the pyrolyzer (700-900°C) and gases, tar, and char were formed. The resultant char was circulated with bed material to the combustor, and combusted completely or partially. During partial combustion, some chars were combusted, and the uncombusted chars were circulated back to the pyrolyzer (termed char recycling). During char recycling, the recycled char could contact tar derived from pyrolysis, and the volatile-char interaction was enhanced with char recycling time. The product gas yield, mainly H 2 and CO, increased, whereas the heavy and light tar yields decreased with char recycling.

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Section: Reduction Of Light Tar With Char Recyclingmentioning

confidence: 99%

Reduction and Reforming of Tar with Enhanced Volatile-Char Interaction during Coal Pyrolysis

Kawabata¹,

Wajima²,

Nakagome³

et al. 2015

IJCEA

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“…A-8 (Bruinsma, 1988;Nelson, 1986;Chen, 1992). The abundance of soot, CO, and combustion products in the secondary products ensures that they will burn relatively slowly (Marlow et al, 1992;Cho et al, 1995).…”

Section: Primary Devolatilizationmentioning

confidence: 99%

“…The primary product distributions from FLASHCHAIN ® are converted to secondary pyrolysis products by applying pseudo-mechanisms based on the study of Chen et al (1992). The distributions incorporate an extent of secondary pyrolysis, but not finite-rate kinetics.…”

Section: Secondary Volatiles Pyrolysismentioning

confidence: 99%

DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

Felix¹,

Bush²

2002

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“…An increasing fraction of the char-N was converted to HCN with increasing temperature 3 . Table 4-1 shows predicted composition of coal gasification products.…”

Section: Composition Of Coal Gasification Productsmentioning

confidence: 99%

Minimization of Carbon Loss in Coal Reburning

Vladimir¹,

Lissianski²,

Maly³

et al. 2002

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This project develops Fuel-Flexible Reburning (FFR) technology that is an improved version of conventional reburning. In FFR solid fuel is partially gasified before injection into the reburning zone of a boiler. Partial gasification of the solid fuel improves efficiency of NO x reduction and decreases LOI by increasing fuel reactivity. Objectives of this project were to develop engineering and scientific information and know-how needed to improve the cost of reburning via increased efficiency and minimized LOI and move the FFR technology to the demonstration and commercialization stage. All project objectives and technical performance goals have been met, and competitive advantages of FFR have been demonstrated.The work included a combination of experimental and modeling studies designed to identify optimum process conditions, confirm the process mechanism and to estimate cost effectiveness of the FFR technology. Experimental results demonstrated that partial gasification of a solid fuel prior to injection into the reburning zone improved the efficiency of NO x reduction and decreased LOI. Several coals with different volatiles content were tested. Testing suggested that incremental increase in the efficiency of NO x reduction due to coal gasification was more significant for coals with low volatiles content. Up to 14% increase in the efficiency of NO x reduction in comparison with basic reburning was achieved with coal gasification. Tests also demonstrated that FFR improved efficiency of NO x reduction for renewable fuels with high fuel-N content.Modeling efforts focused on the development of the model describing reburning with gaseous gasification products. Modeling predicted that the composition of coal gasification products depended on temperature. Comparison of experimental results and modeling predictions suggested that the heterogeneous NO x reduction on the surface of char played important role.Economic analysis confirmed economic benefits of the FFR technology. Two options to gasify coal were considered: one included a common gasifier and another included a gasifier injector at each injection location. Economic analysis suggested that an FFR system with a common gasifier was more economic than a conventional reburning system and had NO x reduction cost similar to that of the major competing technology, LNB/SOFA system, for all economic scenarios. DOE Contract No. DE-FC26-00NT40912 Draft Final Report 4 Table of ContentsSection PageList of Tables ---The Problem of Ash Utilization Associated with NO x Reduction Technologies----15 Figure 4-5. Reactor diagram of model setup---------------------------------------------------- -entrained gasifier --------------------------------------------------------- Tables Table Page Table 3 Table 5-2. Common gasifier: cost impacts relative to conventional coal reburn -------------66 Table 5-3. Gasifier injector: cost impacts relative to conventional coal reburn --------------66 Table 5-4. Coal reburn economics in OTR 370 MW opposed wall unit----------...

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Coal devolatilization during rapid transient heating. 2. Secondary pyrolysis

Cited by 114 publications

References 0 publications

Reduction and Reforming of Tar with Enhanced Volatile-Char Interaction during Coal Pyrolysis

Reduction and Reforming of Tar with Enhanced Volatile-Char Interaction during Coal Pyrolysis

DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

Minimization of Carbon Loss in Coal Reburning

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