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Dear reader,
GAFT is well into its third year and all the sub-projects are hectically working on the different deliverables. So far in 2017 we have arranged a workshop that disseminated in detail the modeling concept of the value chain case that has been developed. The workshop was also used as a two-way communication channel, where the feedback from partners was directly used for improving the cost models in some parts of the evaluated value chain. A steering committee meeting was also held prior to the workshop, which was a good opportunity to update partners on the progress of the entire project. Below you will find a progress update over what has been done so far in 2017 in the different sub-projects. Roger Khalil, GAFT project manager |
Progress update on feedstock pretreatmentDuring entrained flow gasification of biomass fuel, the total ash melting in addition to viscosity are critical for smooth operation of the gasifier. Spruce wood will be used as the main fuel in GAFT, and has a low content of ash that melts at a rather high temperature. Mixing of the spruce wood with different additive fuels is an efficient way to increase the amount of ash and especially certain ash elements that will contribute to a reduction of the ash melting temperature. Intensive experimental work and analyses have been done for studying the melting behaviors of spruce wood and its mixtures with three different additive fuels, constituting of bark, forest residue and Ecopro digested residue. The ash fusion results showed that the melting temperature of the spruce wood ash can be considerably decreased upon mixing with the three tested additive fuels. Detailed SEM-EDX analyses were carried out to study the microstructure and microchemistry of ash residues obtained from sintering tests performed at elevated temperatures. The SEM-EDX revealed that at 1200 °C, the spruce wood ash had loose structure and contained mainly agglomerated calcium-rich particles and grains. However, the ash from the mixture of spruce wood and forest residue had already melted at 1200 °C and appeared to have a clear fused structure. The EDX analyses results showed that the melted ash fraction contained significant amounts of K, P and Si. These elements are mainly coming from the forest residue and their presence enhanced the formation of low temperature melting materials and the fusion of the ash consequently. |
SEM-EDX analysis of ash produced from (a) spruce wood and (b) mixture of spruce wood with 10 wt% of forest residue at 1200 °C. |
The above-mentioned results were presented by the research scientist Liang Wang from SINTEF Energy Research at the Second International Bioenergy Conference and Exhibition (IBSCE 2017), which was held in Shanghai, China, on the 19-21 of April, 2017. The IBSCE is a leading conference series and platform bringing together field experts, academics and business innovators to promote development of bioenergy as a valuable economic source in Asia and beyond. In the technical session named Research in the Gasification Technology and Ash Chemistry, the results from the SINTEF-led project GAFT were presented. The title of the presentation was: "Ash Fusion Characteristics of Spruce Stem Wood and Blends with Bark and Forest Residue". |
Disseminating GAFT SP1 activities at the IBSCE 2017. |
Progress update on entrained flow gasificationExperimental work Recently, all partners in GAFT were updated about delays in SP2 due to challenges related to process control and safety systems. The deliverables related to SP2 are still planned to be delivered in the current year. Work have been concentrated lately on testing the functionality of subsystems such as the syngas burner. Also in preparation for the experimental campaign that is planned after the summer, all the gas analytical equipment have been tested and moved to the SINTEF Energy Lab in Blaklia. The gas lines for taking continuous measurements for the quantification of gas and particle concentrations have been designed and all the parts have been purchased. For the particle measurements by the ELPI (Electrical Low Pressure Impactor), the line will be actively heated in order to avoid condensation, which can lead to errors in counting particles. HSE for the gas lines has been performed and will include purging the entire line with nitrogen and gas dilution with nitrogen for the ELPI line in order to avoid the risk of spontaneous ignitions inside the ELPI. The lines will be built and tested before the start of the summer vacation. Modelling Pulverized biomass particles are usually non-spherical but most CFD simulations treat them as spheres. This simplified assumption can lead to significant differences in simulation results compared to the real situation since drag forces of non-spheres are different from spheres and particle rotational effects should be included for simulations with non-spheres. The hypothesis is that when using spheroids, instead of spheres, to model pulverized biomass particles, CFD simulations will produce different particle trajectories and conversion histories. In this regard, a new model that treats pulverized biomass particles as spheroids is implemented into OpenFOAM (Open Source Computational Fluid Dynamics Toolbox). In this model, particle drag force and torque are modified. The implementation of spheroidal torque is validated with DNS data from Lihao Zhao (NTNU, Tsinghua University). Whereas, the implementation of spheroidal drag force is validated by comparing with the terminal velocity of spherical particle. Preliminary result (see the figure below) shows that spheroidal particles have different trajectories in comparison to spherical particles. Furthermore, particle initial orientation and aspect ratio play a role in altering particle trajectories. These results have been presented at the "Sixteenth International Conference on Numerical Combustion" in Orlando, which took place on 3-5 April 2017. In additional to research, the PhD candidate has taken two educational courses and one training course this spring (Heat and Combustion Technology and Advanced Computational Fluid Dynamics, and Open Source CFD for industry – high-level development). |
CFD simulations show that spherical particles and spheroidal particles have different trajectories when injected into an airflow (10m/s upwards) field. The initial orientation of spheroidal particles affects their trajectories. (Source: Guo, Ning; Li, Tian; Løvås, Terese (2017). Eulerian-Lagrangian Simulation of Non-Spherical Biomass Particles in Turbulent Flow. Sixteenth International Conference on Numerical Combustion, Orlando, Florida.) |
Progress update on Fischer-Tropsch testingIn GAFT, a Fischer-Tropsch catalyst will be utilized in a medium to high temperature range for synthesis of biocrudes from the gasifier syngas. The productivity of cobalt-based catalysts is known to be much higher than that of iron-based catalysts. However, since iron-based catalysts are much cheaper, impacting on the overall cost of the process, it is debatable whether a cobalt-based catalyst is truly the optimal catalyst for all BTL-processes. Syngas coming from the entrained flow gasifier will typically have H2:CO ratio close to 0.5. To utilize the potential of the Co-based catalyst, increasing the H2:CO ratio in the syngas with water-gas-shift (CO + H2O = CO2 + H2) is necessary. In the GAFT project, six cobalt- and six iron-based Fischer-Tropsch catalysts have been tested in laboratory fixed-bed reactors at relevant FT conditions. All catalysts are tested at reactor temperatures from 210 to 270 °C and H2:CO ratios from 1 to 2, with and without CO2 in the syngas. Selected results obtained with H2:CO = 1.0 are shown below. A general trend is that Fe based catalysts give lower CH4 and higher CO2 selectivity than the Co-based catalysts. For the biofuel production process, many factors might affect efficiency and performance of a catalyst and the final product yield. The project will continue with more detailed process studies on an iron-based catalyst, i.e. the effect of H2/CO << 1 on product selectivity and catalyst stability. |
Some results obtained with H2:CO in the syngas feed. |
Progress update on value-chain analysisThe techno-economic analysis performed in GAFT SP4, which evaluates the decentralized production of Fischer-Tropsch biocrudes by co-processing woody biomass and sludge residues from anaerobic digestion in an entrained flow gasifier, has recently been published in Energy & Fuels. The co-processing strategy proposed in this work, shown in the figure below, represents a novelty in the literature and aims to reduce the overall production cost of liquid biofuels for the heavy-duty transport sector by reducing the cost of feedstock supply and through a better utilization of the residual heat recovered from the overall production process. |
A process overview of the co-processing strategy that was employed in the recent publication. The main results from this paper show that co-processing improves the overall cost of biocrude production from Fischer-Tropsch synthesis when considering gate fees for the sludge above 20 $/ton. For this gate fee, although co-processing sludge requires higher capital investment for pretreatment, the reduction of feedstock supply cost with increasing fraction of sludge becomes dominant in evaluating the overall cost of production. For gate fees of 50 $/ton, which are realistic for the current waste market, the cost of biocrude ranges between 18 and 22 $/GJ for plant scales between 150 and 600 MW based on the input feedstock energy to the entrained flow gasifier. Moreover, the overall efficiency for biocrude and LNG production, and therefore the main income to the plant, is comparable for mass fractions of the sludge in the raw feedstock ranging between 0 and 50%. The proposed conversion route is relevant commercially since the hydrocarbon products from Fischer Tropsch synthesis, which have ultra-low concentration of sulfur, oxygen and nitrogen, can be fractionated and upgraded to market-quality liquid fuels at existing petro-chemical facilities, as co-feeds of fossil-derived crude fractions, using the final steps in the refining processes. The techno-economic analysis of upgrading Fischer-Tropsch products in existing refinery processes will be the topic of a new paper to be submitted at the end of 2017. Also, the published paper reports a parametric model for evaluating the process and economics of the biocrude production plant. This parameterization will be integrated and used in a wider mathematical model to evaluate the economic performance of business models for liquid biofuels production in a value chain perspective. This analysis, to be finalized in 2018, will include an evaluation of how uncertainties and variabilities along the value chain affect the economic performance. |
Other newsActivities in IEA task 33: Gasification of Biomass and Waste The first task 33 meeting in 2017 was held in Innsbruck, Austria on 2 May followed by a workshop on small-scale biomass gasification for CHP on 3 May and a study tour to Syncraft and GE Jenbacher on the 4th. The scope of the task meeting was to go through recent developments in the member countries as well as the planned special projects for this triennium (2016-2018). The following special projects will be carried out during these three years:
• SP1: Waste gasification
• SP2: Fuel pretreatment for gasification systems
• SP3: Biomass gasification for CCUS
• SP4: Biomass gasification success stories
• SP5: Gasification‐based hybrid systems
• SP6: Hydrogen production via gasification
• SP7: Biomass and waste gasification status report
• SP8: Biomass gasification history and lessons learned
• SP9: Valorization of byproducts from small scale gasification
The workshop on the 3rd was followed by company technology presentations from Urbas, Meva, Cortus Energy, CMD, Ronda and Torrgas. From the engine side, GE Jenbacher presented how they develop engines for biomass syngas utilization. Another topic of the workshop was how to valorize the by-products, especially the benefits of biochar but also using the ashes as fertilizers was mentioned. During the study tour the Syncraft plant near Innsbruck as well as the engine manufacturing lines at GE Jenbacher were visited. More information about the reports from the member countries, special projects and the workshop presentations can be obtained on the task webpage as well as by contacting Judit Sandquist. |
A group photo of the IEA task 33 delegation taken during the first meeting in 2017 which was held in Innsbruck, Austria. |
Calendar of events
• European Biomass Conference and Exhibition
June 12-15, 2017. Stockholm, Sweden
• The 7th International Conference on Algal Biomass, Biofuels and Bioproducts
June 18-21, 2017. Miami, USA
• 5th World Bioenergy Congress and Expo
June 29-30, 2017. Madrid, Spain
• BIO World Congress on Industrial Biotechnology
July 23-26, 2017. Montreal, Canada
• International Conference on renewable energy and resources
July 24-25, 2017. Vancouver, Canada
• 8th International Conference on Biofuels, Bioenergy & Bioeconomy
December 4-5, 2017. Sao Paulo, Brazil
• 2nd World Biodiesel Congress & Expo
December 06-07, 2017. Dallas, Texas, USA
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