Preliminary status note: Thermal biomass conversion technologies ...

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2.4. Fast Pyrolysis Technology 2.4.1 Short description of technology 10 By pyrolysis of biomass in the absence of oxygen a large fraction of the biomass can be converted to bio-‐ oil, and smaller amounts of char and gas. Biomass such as wood, agricultural residues and waste products can be used as feedstock for fast pyrolysis processes. A maximum oil yield is in most cases obtained at reactor temperatures between 450 and 600°C with a high feedstock heating rate and a short gas residence time. The bio-‐oil mass yield obtained from various biomass sources are in the range of 30 – 75 %wt. Wood having a low ash content and a high cellulose content is often found to provide a high bio-‐oil yield of 70 – 75 %wt. The generated bio-‐oil has high oxygen content, cannot be distillated and may in some cases have a limited storage stability. The oil can be utilized as a heavy fuel oil in boilers, while it in most cases needs some upgrading by hydrogenation if the oil shall be used in diesel engines or gas turbines. Two classes of reactor types that can obtain high biomass feedstock heating rates have mainly been developed for flash pyrolysis plants, ablative reactors and fluid bed reactors. In an ablative reactor high heating rates is obtained by pressing the fuel particles towards a hot metal surface, while the high heating rate in a fluid bed reactor is obtained by a fast mixing of hot inert bed material and the fuel. Recently it has been proposed, that the char from the pyrolysis process can be used as bio-‐char that is distributed on agricultural fields, and thereby act as a method to sequestrate carbon (Bruun et al. 2011). 2.4.2 Global status of technology development The most active research community regarding fast biomass pyrolysis is at Aston University in the UK, and the research group is headed by A. V. Bridgwater (Bridgwater 2012). The construction of commercial and pilot pyrolysis plants has gradually increased the last 10 years and initially most plants were constructed in Canada. Today both pilot and commercial plants are constructed in several countries as seen in Table 1. The largest planed pyrolysis plant is the construction of a 400 tpd plant that has been announced by Alberta placed Tolko industries LTD using the Ensyn developed CFB technology. Table 1: Global survey of major technology developments of fast pyrolysis. Tpd = Tons produced daily. (Butler et al. 2011). Company Technol Developments Dynamotive BFB Several plants, largest is 200tpd at west Lorne (CAN) Ensyn CFB Several plants, largest is 100tpd plant in Renfrew (CAN); construction of 400 tpd plant in High Level, Albarta (CAN) with Tolko Industries LTD. Announced; Construction of 9 plants in Malaysia by 2015 announced BTG RCR 120 tpd plant in Hengolo (NL) announced production of bio-oil, electricity, organic acids B-O H N.V. RCR Largest plant is 12 tpd. Construction of two 5 tpd plants underway in NL and BEL Biomass Eng. BFB 4.8 tpd facility (UK) KIT/Lurgi Auger 12 tpd pilot plant in Karlsruhe (GER) Pytec Abliative 6 tpd plant (GER) Anhui Yineng M.FB Three 14 tpd units constructed (CHI) Metso Consort CFB 7.2 tpd pilot plant at tampere (FIN)
2.4.3. Danish strong positions and facilities 11 At DTU department of chemical engineering the patented flash pyrolysis centrifugal reactor (PCR) is under development (Bech 2008)(Bech et al. 2009). Research is conducted on a 3 kg feedstock/h laboratory unit and includes studies on using different feedstock’s including straw, lignin and waste fractions as well as studies on reactor optimization and oil storage stability. Also studies on using slurry of char and bio-‐oil as a feedstock for pressurized gasification is done and the use of the char for carbon sequestration. The patent rights for using the PCR technology to treat different waste types are partly owned by DONG energy. The PCR technology can be used in stationary and also be developed to a mobile unit, which can make pyrolysis oil directly from straw on the fields. At DTU also work on hydrogenation of bio-‐oil is done (See other section in this note) Only few Danish companies work with pyrolysis technologies. Organic fuel technology A/S is developing a catalytic low temperature pyrolysis process (Hansen 2011) . Details about the plant are not known. Stirling DK Aps have developed the BlackCarbon pyrolysis process (Hansen 2011). Biomass is pyrolyzed at a low heating rate and the generated gas and tar are combusted and drives a sterling engine. The generated bio-‐ char is used as a soil improver and to sequestrate carbon. 2.4.4. Perspectives The Pyrolysis reactor technology can be used both as stand alone plants and plants integrated with other energy conversion processes. While the most commercially developed pyrolysis plants are based on fluid bed technology integration with other energy processes is only in it infancy. - The fast pyrolysis technology may be used at relatively small local units to treatment of savage sludge, hazardous waste or to convert lignin (From a bio-‐ethanol plant) or be used to treat selected waste fractions (as a part of the Renescience process). - It has been proposed to use local pyrolysis plants combined with central gasification or central bio-‐ oil upgrading plants. - Compared to gasification based production of liquid fuel, the pyrolysis technology can for some feedstock types (as wood) provide liquid fuel with high energy efficiency. The drawback is the relatively low quality of the bio oil. However, only smaller modifications of the pyrolysis oil may be needed if the oil could be used as a low sulfur oil for heavy ship diesel engines. - The DTU PCR concept is designed so it can evolve into in-‐situ mobile pyrolysis units, which can be applied to harvest bio-‐oil from straw directly on the farmer’s fields. Such a technology could strongly increase the global straw resources that economically can be applied for power production. - As a byproduct from the pyrolysis project a Bio-‐char is produced that potentially can be used for soil improvement and carbon sequestration. - Flash pyrolysis of biomass to produce slurry (bio-‐oil-‐char) may be a pretreatment step used on pressurized biomass gasification plants. 2.4.5 Bibliography (Butler et al. 2011). Butler E, Devlin G, Meier D, McDonnell K. A review of recent laboratory research and commercial developments in fast pyrolysis and upgrading. Renewable and sustainable energy reviews 15 (2011) 4171 – 4186.
Page 1 and 2: 1 5/4 2012 Preliminary status note:
Page 3 and 4: 2.1. Entrained flow gasification 2.
Page 5 and 6: (Hansen 2011) Morten Tony Hansen. S
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Page 19: 9. Haldor Topsøe AS, inventor; Hyd

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