CO2 gasification of biogenic fuels in a dual fluidized bed reactor system

Mauerhofer, Anna Magdalena; Müller, Stefan; Benedikt, Florian; Fuchs, Josef; Bartik, Alexander; Hofbauer, Hermann

doi:10.1007/s13399-019-00493-3

Cited by 11 publications

(6 citation statements)

References 36 publications

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“…In agreement with the results in Figure 6, the highest tar concentrations in dry gas are for lignin residue. This result is in agreement with CO 2 /steam gasification results obtained in a dual fluidised bed with the same feedstock (oak bark and lignin residue) [25]: even if the gasification was performed at higher temperature for lignin residue, the tar content was significantly higher than for oak bark. On the other hand, the tar contents for bark and bark/wheat straw blends are not much different.…”

Section: Tar Content and Compositionsupporting

confidence: 91%

Fluidised Bed Gasification of Diverse Biomass Feedstocks and Blends—An Overall Performance Study

et al. 2020

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The aim of this work is to investigate the fluidised bed gasification of several pure and blended feedstock prepared in the form of pellets: oak bark, two bark/wheat straw blends (85/15 and 50/50 wt%) and lignin residue remaining from bioethanol production. Gasification conditions were defined to be representative of dual fluidised bed ones (steam gasification at 850 °C, followed by air combustion of the char). The cold gas efficiency (77–81%), gas composition and tar content (0.9–2.3 g/kgdaf) are close for the gasification of bark and the two bark/wheat straw blends. For lignin residue, the cold gas efficiency is lower (71%), and the tar content is 9.1 g/kgdaf. The agglomeration propensity is much higher for lignin residue than for the other feedstock. This was put into evidence with in-bed temperature measurements at different levels, and confirmed with post-test size screening of the bed material particles. The 50/50 wt% bark/wheat straw blend seems to undergo defluidisation in combustion, however followed by refluidisation of the bed. These findings were also well correlated with a predictive model for defluidisation.

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Section: Tar Content and Compositionsupporting

confidence: 91%

Fluidised Bed Gasification of Diverse Biomass Feedstocks and Blends—An Overall Performance Study

et al. 2020

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“…All displayed feed gas compositions are obtained with a new generation 100 kW th DFB gasifier at TU Wien. The DFB process is not elaborated in this study and further information can be found in literature [4,7,8,56,60,61]. The lower part of Table 1 depicts the gas compositions which are derived from the DFB gasification process and are in further consequence used as the feed gas compositions for the methanation process.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic investigation of SNG production based on dual fluidized bed gasification of biogenic residues

Bartik

Benedikt

Lunzer³

et al. 2020

Biomass Conv. Bioref.

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Natural gas is an important commodity in the European energy market. The gasification of biogenic residues and the further reaction to a methane-rich gas represent a promising concept for the production of synthetic natural gas on a fossil-free basis. This paper investigates the thermodynamics of methanation in a fluidized bed reactor for different product gas compositions of the dual fluidized bed gasification technology. The investigated product gases range from conventional steam gasification, over CO2 gasification, to product gases from the sorption enhanced reforming process. All investigated product gases from conventional steam gasification show an understoichiometric composition and therefore require a proper handling of carbon depositions and a CO2 separation unit downstream of the methanation reactor. The product gas from CO2 gasification is considered disadvantageous for the investigated process, because it only exhibits a carbon utilization efficiency of 23%. Due to the high flexibility of the sorption enhanced reforming process, a nearly complete methanation of the carbonaceous species is possible without the need for a CO2 separation step or the addition of steam upstream of the methanation reactor. Furthermore, the carbon utilization efficiency is found to be between 36 and 38%, similar to the results for conventional steam gasification. Temperature and pressure variations allow a thermodynamically optimized operation, which can increase the performance of the methanation and lower the extent of gas upgrading for grid feed-in. Additionally, if a higher hydrogen content in the natural gas grid would be allowed, the overall process chain could be further optimized and simplified.

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“…11 shows the CO 2 conversion rate X CO2 , which gives the ratio of consumed CO 2 during gasification to the amount of CO 2 introduced into the GR via CO 2 as gasification agent and CO 2 produced from the pyrolysis of the fuel. Detailed information about the calculation of X CO2 can be found in [10]. X H2O is defined as the steam-related water conversion.…”

Section: Validation Of Process Data With Ipsementioning

confidence: 99%

“…However, the use of CO 2 as gasification agent presents a novel research topic. First experimental test runs using mixtures of steam and CO 2 were already carried out, starting in 2018 [9,10]. The main findings of these test runs were: & In contrast to pure steam biomass gasification, where a hydrogen (H 2 )-rich product gas is generated, a carbon monoxide (CO)-rich product gas is created, when CO 2 is used as gasification agent.…”

Section: Introductionmentioning

confidence: 99%

Conversion of CO2 during the DFB biomass gasification process

Mauerhofer

Müller

Bartik

et al. 2020

Biomass Conv. Bioref.

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In many industrial processes, the climate-damaging gas CO2 is produced as undesired by-product. The dual fluidized bed biomass gasification technology offers the opportunity to tackle this problem by using the produced CO2 within the process as gasification agent. Therefore, a 100 kWth pilot plant at TU Wien was used to investigate the use of CO2 as gasification agent by converting softwood as fuel and olivine as bed material into high-valuable product gas. A parameter variation was conducted, where the typically used gasification agent steam was substituted stepwise by CO2. Thereby, the amount of CO and CO2 increased and the content of H2 decreased in the product gas. These trends resulted in a declining H2/CO ratio and a decreasing lower heating value when CO2 was increased as gasification agent. In contrast to these declining trends, the carbon utilization efficiency showed an increasing course. As second part of this work, a temperature variation from 740 to 840 °C was conducted to investigate the change of the main product gas components. With increasing temperature, CO and H2 increased and CO2 decreased. To determine the degree of conversion of CO2 in the DFB reactor system, two approaches were selected: (1) a carbon balance and (2) a hydrogen balance. This way, it was found out that a certain amount of CO2 was indeed converted at the investigated process conditions. Furthermore, under certain assumptions, the reverse water-gas shift reaction was identified to be the predominant reaction during CO2 gasification.

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CO2 gasification of biogenic fuels in a dual fluidized bed reactor system

Cited by 11 publications

References 36 publications

Fluidised Bed Gasification of Diverse Biomass Feedstocks and Blends—An Overall Performance Study

Fluidised Bed Gasification of Diverse Biomass Feedstocks and Blends—An Overall Performance Study

Thermodynamic investigation of SNG production based on dual fluidized bed gasification of biogenic residues

Conversion of CO2 during the DFB biomass gasification process

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