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Reporting period: 2019-09-01 to 2021-04-30

FLEXCHX was a three-year project (2018-2021), which developed a flexible and integrated hybrid process combining electrolysis of water with gasification of biomass and catalytic liquefaction. The FLEXCHX concept constitutes a complete rethinking of how combined heat and power should be produced in variable renewable energy-dominated power grids, and how the use of excess solar and wind energy can be combined with effective use of biomass residues. The FLEXCHX process can be integrated with various combined heat and power production systems, both industrial CHPs and communal district heating units. In the summer season, renewable fuels are produced from biomass and hydrogen; the hydrogen is produced from the water via electrolysis that is driven by low-cost excess electricity from the grid. In the dark winter season, the plant is operated only with biomass in order to maximize the production of the much-needed heat, electricity, and FT hydrocarbons. Most of the invested plant components are in full use throughout the year, only the electrolysis unit is operated seasonally.

The overall goal of FLEXCHX was to develop a flexible energy production process that can be operated in the future European energy mix throughout the year with high efficiency and low cost. The aim was to develop all key enabling technologies of the process, the gasifier, hot filter, catalytic reformer, sorbent-based final gas cleaning, and the flexible and compact FT synthesis to TRL5 and to validate the operation at pilot-scale tests.
The project was organized in nine work packages: WP1 Coordination and Management; WP2 Concept development; WP3 Gasification and raw gas cleaning; WP4 Reforming and final syngas cleaning; WP5 Flexible FT synthesis; WP6 Validation of the key enabling technologies; WP7 Integration of FT products to refineries; WP8 Techno-economic & environmental assessment of the process concepts, and WP9 Dissemination and Exploitation. WP3, WP4 and WP5 were technical development work packages for the key enabling technologies of the project. In WP3 an existing fixed bed gasification pilot plant of VTT was modified into a pressurized staged fixed gasifier followed by hot filtration and catalytic reforming units. This process was then flexibly operated with mixtures of oxygen, air, steam and carbon dioxide as the gasification agents simulating different operating modes of the FLEXCHX process. Five successful one-week-long gasification tests were realised with a total of 350 hours of operation under gasification. The raw gas was filtered from particulates in a hot filter unit consisting of 12 robust metal filters. The filter unit could be operated with stable pressure drop and the goal of total particulate removal was achieved. The filtered gasification gas was led into the catalytic reformer, which was developed in WP4. In the reformer, tars and light hydrocarbon gases were effectively reformed and the synthesis gas approached the equilibrium of homogeneous water gas shift reaction. In WP4, the reformer process concept was developed by VTT, while Johson Matthey developed and tested highly efficient and impurity tolerant catalysts for this process. In WP5, Ineratec used their laboratory and bench-scale test facilities for studying the performance of their Fischer-Tropsch synthesis technology with various gas compositions representing different operating modes of the FLEXCHX process. In WP6 the operation of the whole gasification, gas cleaning, and FT synthesis process was validated by carrying out two test weeks with the integrated operation. The experimental development and validation work packages were successfully completed and all key steps of the process were developed to TRL5.

WP2, WP7, and WP8 supported the experimental development and validation activities. The status and outlook of electrolysis technologies were reviewed by DLR, the biomass feedstock potential in the target countries was studied by Enerstena, VTT and LEI. LEI together with Helen studied the CHP markets in Lithuania and Finland and made a preliminary design on how to integrate the FLEXCHX process to selected CHP systems. In WP7, Neste Engineering Solutions NES made a study on the market outlook of biofuels and examined how the FT products produced at distributed FLEXCHX plants can be introduced to the processes of the oil refining industry. In WP8, DLR made a simulation model for the whole FLEXCHX process and carried out techno-economic and LCA studies. This work was completed by carrying case studies in the conditions of the Helsinki and Kaunas regions. The case studies indicated that already under present market conditions, the FLEXCHX plant looks economically attractive if the value of FT hydrocarbon is > 100 €/MWh corresponding to 1160 €/t. Considering the value of renewable diesel and aviation fuels on the European markets, this can be considered already quite attractive. However, the risks and additional costs of the first-of-a-kind plants are challenging and thus these plants require substantial public support.

Preliminary plans for follow-on industrial demonstration were also assessed in the project and various types of pathways were identified. In principle, the FlexCHX- concept can be realized with different combinations of individual technologies, which opens possibilities for organizing the demonstration also at larger-scale fluidized-bed gasification sites as well as in projects focusing on the production of other end-products, such as synthetic methane or methanol. All these cases will make it possible to build a hybrid process integrating the use of electrolysis and biomass-based syngas. The developed new technologies can also be applied separately in many alternative applications, which opens several promising possibilities for industrial demonstration.
FLEXCHX concept progressed beyond the present state-of-the-art in several areas as summarized below:
• The proposed way of integrating low-cost variable electricity with biomass gasification captures this otherwise curtailed energy with minimal losses and simultaneously converts biomass carbon to valuable and urgently needed transport fuels
• Tri-generation of power, heat and fuel intermediates allows flexible operation of production units that follow market signals for these energy products.
• The main novel approach of FLEXCHX is the method for operating the plant flexibly under different operating modes, either maximizing the production of transport fuel intermediate (solar season) or maximizing the overall efficiency to power, heat and fuel component (heating season).
• FT wax is an ideal intermediate product that can be collected from several primary plants to centralized refineries, where high-quality fuels are produced for aviation, maritime and heavy duty road transport.
• The new process for flexible production of heat, power and fuels at the target scale of 5-50 MW (where most of the CHP potential is) is based on the development of highly innovative new technologies
Experimental approach of FLEXCHX project
Operation of the FLEXCHX process in summer season
Operation of the FLEXCHX process in dark heating season