报告题目：Agglomeration, defluidisation and their countermeasures for biomass combustion in fluidised beds
报告摘要: In this study, the combustion of pelletised problematic biomass fuels (wheat straw and miscanthus) was investigated in a 20 kWth bubbling fluidised bed (BFB) combustor using quartz sand as the bed material. The combustion profiles were established for the two fuels at the bed temperature above 820 ？C with regards to the combustion temperature distribution, pressure variance and defluidisation time. The mitigation of bed agglomeration and defluidisation was investigated by the addition of 1.5 wt% lime to fuel, the addition of 5 wt% dolomite and 5 wt% of molochite to bed materials respectively. All the additives successfully maintained the combustion temperature at 900 ？C for both fuels.
The defluidisation time was significantly extended by over 14 times via adding lime to fuel which provided a continuous on-site agglomeration counter action. 5% wt addition of dolomite to the bed material extended the defluidisation time for both fuels by ca.6 times for straw and 2 times for miscanthus. The use of molochite as bed additive doubled the defluidisation time for miscanthus combustion but did not affect that of straw combustion.
The impacts of the oxy-fuel combustion atmosphere on the performance of bed additives were investigated by using the synthetic oxidiser of 30 vol% O2 and 70 vol% CO2. The experimental results indicated that the CO2-rich atmosphere significantly hindered the performance of dolomite as a bed material additive on the defluidisation time due to the restrained decomposition of dolomite which resulted in less CaO in the bed to counter the formation of K-rich sticky molten phases.
Ash fusion tests were conducted on an ash fusibility furnace with fuel ashes with and without the additives and the results were used to better understand the fuel ash melting process and the effect of additives on the agglomeration and defluidisation behaviour observed with the BFB tests.
Professor Hao Liu，英国诺丁汉大学工程学院讲席教授。英国自然科学基金委（EPSRC）碳捕获和储存及清洁化石博士培训中心副主任。Professor Hao Liu长期从事清洁化石能源与生物质技术的研究与开发，积累了25年的发电厂工程，流化床技术，煤/生物质燃烧和气化，碳捕获，热电联产和可再生能源技术的研究经验。他主持或共同主持了18个由英国EPSRC，TSB，Carbon Trust和其他国家和国际组织资助的研究项目，这些项目的资助总额超过1800万英镑。在洁净化石能源和生物质能源技术领域的研究享有较好的国际声誉，发表学术论文100余篇，目前指导约15名博士后和博士生。