GAFT Newsletter 1-2018

Dear reader

GAFT is now on its fourth and last year. Although some activities will continue in 2019 (e.g. the PhD work), 2018 is considered to be the last "official" year for the project. The last official meeting for the project will be held in the end of the year and we plan to have a two-day event for a final steering committee meeting and a workshop to summarize what we have achieved during the entire project period.

This year will witness the start and hopefully the completion of all deliverables related to entrained flow gasification. These results, together with the conclusions on SP3 (Fischer-Tropsch synthesis) and SP4 (Value-chain analysis), should make our final year both interesting and educational.

Progress update on entrained flow gasification

Reactivity of products of incomplete gasification in a pressurised TGA

The objective of this task is to study the decomposition behaviour and reaction kinetics of soot particles generated by the entrained flow gasifier. The decomposition behaviour of the soot particles will be investigated by conducting thermogravimetric analysis (TGA) experiments with varying conditions that includes heating rate, gas atmosphere and pressure. More detailed understanding of reaction mechanisms and kinetics will be obtained through this work.

It will further provide valuable input for enhancing fuel conversion and reducing fine particle formation in entrained flow gasification processes. The soot particles from entrained flow gasification normally have very small particle size (30 – 500 nm) and different morphology and microstructure compared to solid particles generated from other conversion processes. The first stage of the current work is to develop an experimental method that is suitable for studying reactivity of soot particles. Carbon nano-powder acquired from Sigma-Aldrich (purity > 99.99 %, particle size < 150 nm) is used as a reference material for investigating the effect of gasification conditions and particle structural differences on the reactivity. The weight loss curves (TG) and the corresponding differential weight loss curves (DTG) for the oxidation and gasification of the soot and char in different CO2 concentrations are shown below. It shows clearly that the weight loss is shifted to lower temperatures with increasing CO2 concentration.

TG and DTG curves of reference carbon nano particles obtained at different CO2 concentrations

The internal structure of soot influences soot gasification behaviour significantly. Therefore, the morphology and microstructure of the reference carbon nano particles were studied by using high resolution transmission electron microscopy (HRTEM).

HRTEM images of the reference carbon nano materials

SNG quality assessment at Ecopro

SINTEF Energy Research together with SINTEF Industry have performed a measurement campaign at Ecopro in order to assess the SNG quality that is produced on site. Ensuring a good gas quality is crucial for example in gas combustion engines as some impurities in the gas could result in engine breakdown. We are happy to report that the SNG at the measurement time was of a high quality, satisfying usage in most subsequent processes.

SINTEF on-site at the Ecopro biogas plant in Verdal

Reactor status

As informed earlier, the entrained flow reactor is leakage free and ready for use in initial reactor testing. The plan before the summer vacation is to heat up gradually the core and test all subsystems. After cooldown, the reactor will be tested once more for leakage at 10 bar pressure. We anticipate the start of the measurement campaigns to be just after the summer vacation.

Progress update on gasification modelling (Ph.D. work)

The Ph.D. work continues to simulate entrained flow gasification of pulverized biomass using the spheroidal particle assumption, which is different from the conventional practice where pulverized biomass particles are treated as spheres in the modelling community.

Previously in our work, a spheroidal particle model solver has been implemented into OpenFOAM, an open source CFD platform, and it has been verified. Now the model is validated against an experiment of a PVC particle, falling free in a rectangular tank that is half full of water. After model validation, simulations of a simplified cold flow entrained flow gasification of pulverized biomass have been performed, with the traditional sphere model and the new spheroid model. The axial, radial and tangential velocities of particles and fluid are analyzed. In addition, particle residence times and local concentrations are examined. It is found that the spheroid model predicts more diverse particle residence times and local concentrations.

As a result, it can be expected that shortcomings may exist when simulating biomass particle conversions using spherical particle assumption and better prediction could be obtained with the more realistic spheroid particle model.

The research progress has been presented with the title “Eulerian-Lagrangian simulations of pulverized biomass injection in turbulent flows using spheroidal approximation” at the 2nd International Workshop on Oxy-Fuel Combustion in Bochum, Germany on February 14 – 15th, 2018. In connection to this workshop, we are invited to publish the research work in a full journal paper in a special issue of the journal Fuel.

Particle residence time and particle axial velocity (Uz) in the downstream of the simulated entrained flow gasifier along the reactor radius.

Progress update on Fischer-Tropsch testing

The FeCuKSiO2 catalyst has been chosen for further studies of the effect of process conditions, relevant for the GAFT project, on product selectivities and catalyst stability. Data are also obtained for lower syngas conversions and a kinetic model describing the system is being developed. The first journal paper is published in ChemCatChem 10 (6), 2018.

Progress update on value-chain analysis (Challenges to achieve the 2050 target for decarbonization of the transport sector)

By 2050, 50% of the energy used for the total European transport sector has to be renewable. Taking into account the current strategies for electrification of cars in cities as well as the transport of freight and passengers between cities, Norway needs every year about 145-175 million liters of biojetfuel and 700-900 million liters of biodiesel. If we consider the overall biomass to biofuel conversion efficiency, the total demand of biojetfuel and biodiesel in Norway requires an availability of biomass of approximately 30-35 TWh.

If we now bring into this picture the fact that stationary CHP production in Norway must reach 28 TWh per year 2050, then we end up with a total necessity of biomass of approximately 60-70 TWh by 2050. Today, the available biomass resources in Norway, combining forest wood, residues from cultivated crops and landscape and organic waste is approximately 30 TWh/year. Therefore, to achieve the 2050 targets for decarbonizing the transport sector, Norway needs to more than double the availability of biomass or improve substantially the efficiency of biomass to biofuels conversion.

In this final year of the GAFT project, we will use the value chain model developed in SP4 to quantify more in detail how Fischer-Tropsch biofuels could contribute to the overall 2050 targets of reducing GHGs emissions in the transport sector.

Other news

Activities in IEA task 33: Gasification of Biomass and Waste

The first Task33 meeting in 2018 was held in Alkmaar, near Amsterdam, the Netherlands 7th May followed by a workshop on waste gasification 8th May and a study tour to ESKA and Torrgas 9th May.

During the Task meeting, most emphasis were given to go through the status of the special projects that are due in this triennium. SINTEF Energy Research is involved in the special project Biomass gasification for CCUS, which will be finalized before the summer holiday. The techno-economic study considers two cases, one Norwegian and one Dutch, where 600 MWth gasification plants are coupled with CCS. Luc Pelkmans, the Technical Coordinator for IEA Bioenergy presented the communication and branding strategies and gave comments on the new triennium proposal. The task members presented the latest developments in their countries during the second half of the day.

The waste gasification workshop started with a comprehensive overview of waste gasification, covering history, technologies, plants, regulations, etc. presented by Lars Waldheim. Thereafter the status of large-scale Valmet gasifiers was reviewed followed by technologies and plants from Synova, Eqtec, ESKA, EDF, Proerg and Syncraft. ECN has also showed the lignin gasification results from the European H2020 project, AMBITION.

During the study tour ESKA and Torrgas plants were visited. ESKA converts 25kton/a of paper rejects and produces steam for a nearby cardboard production facility. The plant has been in operation since October 2016. The Torrgas plant is in its final construction stage. The Torrgas process is a modular one, that will convert biomass to syngas and charcoal in several modules via torrefaction instead of direct gasification.

More information about the reports from the member countries, special projects and the workshop presentations can be obtained from the task webpage as well by contacting Judit Sandquist.