In the most northern part of Sweden there is an extensive biobased value chain based on forestry: sawmills, joinery industry, industrialised building industry, pulp and paper mills and an upcoming biofuel and biorefinery industry. In an overall scenario this creates a platform for an attractive bioeconomy to develop according a recent survey.
Figure 2. Schematic over wood flows in the existing biobased forest industry value chain. Figure 1. Schematic flow concept of an oxygen blown entrained flow biomass gasifier. Figure 2. Schematic over wood flows in the existing biobased forest industry value chain.
In the most northern part of Sweden there is an extensive biobased value chain based on forestry: sawmills, joinery industry, industrialised building industry, pulp and paper mills and an upcoming biofuel and biorefinery industry. In an overall scenario this creates a platform for an attractive bioeconomy to develop.
The region consists of the counties Norrbotten and northern Västerbotten and has a vast amount of productive forest land of just over 7 million ha, roughly equivalent to the size of Ireland. The annual production output from these resources includes 1.75 million m3 of wood products, 1.41 million tonnes of pulp and paper, 150 000 tonnes of pellets and 100 000 tonnes of raw talloil diesel.
Upgrading available sidestreams
According to survey conducted on the industry members of the Bothnia Bioindustry Cluster, the value chain processes result in a significant amount of annual biomass sidestreams (see figure 1 below). Examples of gross volumes sidesteams are; 285 000 tonnes of sawdust, 344 000 tonnes of bark, 381 000 tonnes of lignin from black liquor. At present most of these volumes are reused in the internal energy supply chain. However, the ambition of tomorrow is to use those streams for new material and high value energy form in a sustainable approach. This takes a joint effort in closing the technology gap and seek solutions to reducing fossil fuel dependency to reach the Swedish 2030 fossil independence goal. Innovations are urgently needed to open up the potential of the emerging market for biomaterials, bioenergy and biofuels to a larger extent than today.
For over two decades there has been a technology push to explore the thermo-chemical processes for energy conversion and value-added products from low value bulk side streams. Examples of such thermo-chemical processes are:
• Gasification of biomass to obtain syngas for upgrading to bioenergy, biofuel or biochemical use
• Pyrolysis of biomass in absence of oxygen to obtain pyrolysis oil for combustion or upgrading to biochemical or biofuel
• Hydrolysis or mechanical disintegration and fractionation into biomass derivate for biocomposites
The core issue for all of them is feedstock constitution, operating residence time, temperature and pressure, the storage and stability of downstream product and the overall energy and mass balance. Those fundamental aspects give guidance on how to build for technological maturity.
Technology push into market pull
One technology push has guided into the demonstration of pressurised, oxygen blown, entrained flow gasification of forest residues (see figure 2). This technology to produce syngas followed by gasoline production is one roadmap for the production of synthetic biofuels. The benefits with entrained flow gasification, compared to other gasification technologies, is the high quality syngas that is generated which is a necessity for the downstream production of gasoline.
In this technology push, pilot-scale gasification research has been carried out at the Swedish Research Institute (SP Energy Technology Center). The gasifier can be operated both with pulverised and liquid feedstock at 1 MWth (≈200 kg biomass per hour), at a process pressure of up to 10 bar and temperatures of up to 1600 °C. Over 790 hours of operational experience have shown proof-of-concept and high overall efficiency. The raw syngas contains high levels of primary CO, H2, and CO2 and secondary low levels of CH4, C2H4 and C2H2.
A thorough analysis of the process performance result of the yields of energetic gases in the syngas represented 75 percent of the energy content in the feedstock. This value is expected to increase and converge to the theoretical maximum of 89 percent in a commercial plant, where the proportion of the heat loss, per installed power, is smaller.
The pilot plant provides a unique opportunity to make CAPEX and OPEX estimations for scaling up into following Technology Readiness Level (TRL) of 7-9 and create a market introduction. The regional outlook brief provides a compelling estimation of the energy equivalent of 1 TWh sidestreams that could be utilised. This ought to attract investment and form a market pull.
References:
• Weiland, F., Wiinikka, H., Hedman, H., Wennebro, J., Pettersson, E., Gebart, R. Influence of process parameters on the performance of an oxygen blown entrained flow biomass gasifier. Fuel 153 (2015) 510-519.
• Weiland, F., Hedman, H., Marklund, M., Wiinikka, H., Öhrman, O., Gebart, R. Pressurized oxygen blown entrained-flow gasification of wood powder. Energy & Fuels 27 (2013) 932-941.
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