Synergy effects of co-firing wooden biomass with Bosnian coal

Kazagic, Anes; Smajević, Izet

doi:10.1016/j.energy.2008.10.007

Cited by 67 publications

(35 citation statements)

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“…They attributed this observation to the high concentration of the particles in the dilution zone of the reactor and the high alkali metals content in the fly and recirculating ashes, enhancing the ability for SO 2 capture in the ash. Similar observations were observed by Kazagic et al [260] in a pulverized fuel entrained flow reactor; they also observed a reduction in sulfur retention with increasing temperature, which was explained due to the reaction of SO 2 with CaO being more efficient at lower to moderate temperatures. For biomasses with a higher content of AAEM and relatively low content of sulfur compared to coal, increasing the ratio of biomass in the blend means increasing the AAEM/sulfur ratio in the blend.…”

Section: Effect Of Blending Coal and Biomass/waste On The Fate Of Sulsupporting

confidence: 76%

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

2014

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Abstract:Biomass is relatively cleaner than coal and is the only renewable carbon resource that can be directly converted into fuel. Biomass can significantly contribute to the world's energy needs if harnessed sustainably. However, there are also problems associated with the thermal conversion of biomass. This paper investigates and discusses issues associated with the thermal conversion of coal and biomass as a blend. Most notable topics reviewed are slagging and fouling caused by the relatively reactive alkali and alkaline earth compounds (K 2 O, Na 2 O and CaO) found in biomass ash. The alkali and alkaline earth metals (AAEM) present and dispersed in biomass fuels induce catalytic activity during co-conversion with coal. The catalytic activity is most noticeable when blended with high rank coals. The synergy during co-conversion is still controversial although it has been theorized that biomass acts like a hydrogen donor in liquefaction. Published literature also shows that coal and biomass exhibit different mechanisms, depending on the operating conditions, for the formation of nitrogen (N) and sulfur species. Utilization aspects of fly ash from blending coal and biomass are discussed. Recommendations are made on pretreatment options to increase the energy density of biomass fuels through pelletization, torrefaction and flash pyrolysis to reduce transportation costs.

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Section: Effect Of Blending Coal and Biomass/waste On The Fate Of Sulsupporting

confidence: 76%

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

2014

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“…However, large amounts of alkali and chlorine in biomass fuels, which are greater than in fossil fuels, result in severe problems of slagging, fouling, and corrosion in heat exchangers of biomass-fired furnaces (Michelsen et al 1998;Demirbas 2005;Davidsson et al 2008;Hansson et al 2009;Kazagic and Smajevic 2009). This is a serious hazard in furnace operations.…”

Section: Introductionmentioning

confidence: 99%

NO Emissions and Combustion Efficiency during Biomass Co-firing and Air-staging

Wang¹,

Wang²,

Hu³

et al. 2015

BioResources

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Experiments were carried out in a drop tube furnace to investigate the effects of biomass/coal co-firing and air staging on NO emission and combustion efficiency. NO and CO emissions along the height of the furnace were monitored by a gas analyzer, and the content of unburned carbon (UBC) in fly ash was also tested. Results showed that NO emission from straw or wood combustion only account for 1/3 or 1/2 that from coal combustion, respectively. Under the conditions of biomass co-firing, the increase in blending ratio had a positive effect on the reduction of NO emission and combustion efficiency. Moreover, results of air-staging combustion showed that for coal combustion, air staging notably reduced NO emission and combustion efficiency. For biomass combustion, the effect was slight. Synergetic analysis indicated that there was an optimum biomass co-firing ratio around 0.4, when the positive synergetic effects on reducing NO emission and UBC were the most significant. When the cofiring ratio exceeded this optimum value, further increasing the co-firing ratio had little influence on NO emission and combustion efficiency. After air staging was adopted, the degree of synergetic effect on NO emissions was reduced while that of UBC was increased.

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“…For vertical walls with parallel particle flow, the ceramic probes for ash collection should be set at an appropriate angle to the particle flow. Furthermore, it should be noted that, as a result of combustion, the coal particle temperature can be higher than that of the furnace wall, with potential implications for the ash transformation and deposition processes, [12]. Specific particle size distribution was used during the tests, as given in Table 2, as well as specific air distribution, as described in previous section.…”

Section: Experimental Uncertainties-assessment Of Applicability and Rmentioning

confidence: 99%

“…Air for combustion, coming from the air blower, is divided into carrier air (primary air), secondary air, tertiary air, and over fire air (OFA). The first three air portions are fed into the furnace over the swirl burner settled on the top of the reactor, so the air-fuel particle mixture flows downward, [12,14,15]. The excess air ratio was adjusted by tuning the air flow in each airline, at a constant fuel flow.…”

Section: Lab-scale Furnace Usedmentioning

confidence: 99%

Co-Combustion of Low-Rank Coal with Woody Biomass and Miscanthus: An Experimental Study

2018

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This paper presents a research on ash-related problems and emissions during co-firing low-rank Bosnian coals with different kinds of biomass; in this case woody sawdust and herbaceous energy crops Miscanthus. An entrained-flow drop tube furnace was used for the tests, varying fuel portions at a high co-firing ratio up to 30%wt woody sawdust and 10%wt Miscanthus in a fuel blend. The tests were supposed to optimize the process temperature, air distribution (including OFA) and fuel distributions (reburning) as function of SO 2 and NO x emissions as well as efficiency of combustion process estimated through the ash deposits behaviors, CO emissions and unburnt. The results for 12 co-firing fuel combinations impose a reasonable expectation that the coal/biomass/Miscanthus blends could be successfully run under certain conditions not producing any serious ash-related problems. SO 2 emissions were slightly higher when higher content of woody biomass was used. Oppositely, higher Miscanthus percentage in the fuel mix slightly decreases SO 2 emissions. NO x emissions generally decrease with an increase of biomass co-firing rate. The study suggests that co-firing Bosnian coals with woody sawdust and Miscanthus shows promise at higher co-firing ratios for pulverized combustion, giving some directions for further works in co-firing similar multi-fuel combinations.

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Synergy effects of co-firing wooden biomass with Bosnian coal

Cited by 67 publications

References 1 publication

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

NO Emissions and Combustion Efficiency during Biomass Co-firing and Air-staging

Co-Combustion of Low-Rank Coal with Woody Biomass and Miscanthus: An Experimental Study

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