Preliminary status note: Thermal biomass conversion technologies ...

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2.2. Fluid bed gasification 2.2.1. Short description of technology 6 In fluid bed gasifiers a fluidized bed of sand is used to obtain stable temperature and mixing conditions in the reactor. Fluidized biomass gasification reactors often operate in the range of 800 to 950°C. The reactors appear in many different designs and sizes. Reactors are used for both small scale plants using internal combustion gas engines to produce electricity and large scale units that can be applied for synthesis gas production. Most fluid bed gasifiers do not operate well on alkali rich biomasses that may cause de-‐ fluidization of the bed. 2.2.2. Global status of technology development Because of the limited time to write this note a status is not provided in this case. 2.2.3. Danish strong positions and facilities The only Danish developed fluid bed gasifier is the Low Temperature Circulating Fluid Bed gasifier (PYRONEER). The concept was originally invented by Peder Stoholm and further development of the gasifier has been conducted by DONG energy and DTU Risø. The PYRONEER has been designed specifically to gasify biomass resources with high contents of low melting ash compounds that has proven difficult to convert in other processes – e.g. straw, manure fibers, sewage sludge, organic waste etc. The process is based on separate pyrolysis and gasification reactors with a suitable heating medium circulating to transfer heat from the gasification process to the pyrolysis. The temperature is kept below the melting point of the ash components – i.e. max process temperatures around 700-‐750 °C. In this way sintering and de-‐fluidization is prevented. The design of the plant ensures that the fuel ash can be removed in a solid phase from the gasifier. The gas produced on the gasifier contains relatively high tar content and will initially be utilized as fuel in a power plant boiler. There presently exist a 500 KWth plant at Risø and a 6 MWth pilot plant is operated by DONG in Kalundborg. The 6 MWth PYRONEER plant will be gasify straw and supply the process gas to Unit 2 of the 1000 MW coal fired power plant Asnæsværket. Operation will begin in March 2011, the project will finish in 2013, and if successful it will be succeeded by a full scale plant. The PYRONEER is a highly scalable concept, with potential plant sizes of 5-‐100 MW depending on the fuel. Desired fuel characteristics include small particle size (3-‐4 mm) and limited water content (< 30 wt%). Successful operation on two different types of straw, chicken manure, two types of pig manure, two types of degassed manure from biogas plants and one type of wood have been carried out on a small scale PYRONEER gasifier at the Technical University of Denmark. These fuels had ash content as high as 44 wt%dry and a high content of potassium, chlorine and phosphorous. To increase the future usability of the PYRONEER process gas, a new project called Gasolution has recently been initiated by a consortium. The aim is to develop new gas cleaning and upgrading techniques that will reduce the content of tar and dust particles in the gas, and make it usable for synthesis or direct production of electricity.
2.2.4. Perspectives The PYRONEER concept may through the activities conducted in the presently started Gasolution project (participants DONG, DTU-‐KT, Haldor Topsoe) leads to production of a gas that has a quality so it can be used for synthesis of chemicals and fuels. 7
Page 1 and 2: 1 5/4 2012 Preliminary status note:
Page 3 and 4: 2.1. Entrained flow gasification 2.
Page 5: (Hansen 2011) Morten Tony Hansen. S
Page 9 and 10: 9 Figure 1: Simplified flow sheet o
Page 11 and 12: 2.4.3. Danish strong positions and
Page 13 and 14: 2.5. Synthesis of transport fuels u
Page 15 and 16: 15 years. Currently it may require
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Page 19: 9. Haldor Topsøe AS, inventor; Hyd

Preliminary status note: Thermal biomass conversion technologies ...

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