雙床氣化爐冷模型中CFB入口速度、BFB床高和顆粒尺寸對矽砂之壓力分佈和質量流率的影響;The Effect of CFB Air Inlet velocity, BFB Bed Height and Particle size on Pressure Profile and Mass Flow Rate of Silica Sand in Dual Bed Gasifier Cold Model

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題名:	雙床氣化爐冷模型中CFB入口速度、BFB床高和顆粒尺寸對矽砂之壓力分佈和質量流率的影響;The Effect of CFB Air Inlet velocity, BFB Bed Height and Particle size on Pressure Profile and Mass Flow Rate of Silica Sand in Dual Bed Gasifier Cold Model
作者:	許啟勝;Kelvianto, Bryan
貢獻者:	能源工程研究所
關鍵詞:	氣化;氣化雙流化床;合成氣;循環流化床;表面速度;床層;鼓泡流化床;Gasification;Dual fluidized bed;Syngas;Circulating fluidized Bed;Superficial velocity;Bed inventory;Bubbling fluidized Bed
日期:	2020-01-17
上傳時間:	2020-06-05 17:22:06 (UTC+8)
出版者:	國立中央大學
摘要:	近年來，技術正在迅速發展。能源需求增加是可以被預期的，而我們需要能源來驅動科技，不可再生原料對於能源的轉化有其局限性的，並且會有造成全球暖化的風險。而氣化技術可以解決這個問題，因為這種方法可以實現乾淨的燃燒並可使用多種原料。雙流化床氣化是一種將燃燒室和氣化室分開的方法，由於將每個室中產生的氣體分離，所以此方法可以產生更高百分比的合成氣。為了將效率最大化，需要對DFB系統的流體動力學進行研究，因為這可以改善系統中的傳熱和傳質。在這項研究中，將使用雙流化床冷模型進行實驗，以分析粒徑從0.3mm到1mm，CFB氣體表面速度從3m / s到4.5m / s以及BFB床高從20cm到35cm影響壓力分佈和床料質量流率。本研究中使用的床層材料為矽砂，因為該為惰性材料是氣化過程中的常用材料。結果表明，隨著粒徑的增加，流動模式將發生變化，質量流速將降低，每種粒徑的壓力分佈將發生變化，可用於確定每種粒徑的緻密和稀薄區域用過的。循環流化床氣體表面速度（VairCFB）的增加將增加CFB下部區域內的壓力，而表面速度的過剩將增加CFB上部區域的壓力，同時降低底部產生的壓力。儘管床層存量（通過鼓泡流化床床高{hBFB}的差異觀察）將增加固體循環質量流量，但是床層過多將對系統產生負面影響，因為這會降低質量流率。根據此結果，可以確定用於DFB冷模型設計的最佳參數是使用0.3 mm矽砂粒，3.5m/s VairCFB和30cm hBFB的矽砂，因為這種配置將提供更好的固體循環並防止過多的顆粒從系統中丟失。這項研究的貢獻在於每個實驗的結果都可用於確定良好的操作參數，以及改善DFB設計。;In the recent years, technology has been rapidly developing. With this, an increase in energy consumption is to be expected. The conversion of non-renewable feedstocks to energy has its own limit and already posed a risk of global warming. Gasification technology can be used to counter this problem since this method gives a clean combustion and large range of feedstocks can be used. Dual fluidized bed gasification is a method that separates combustion and gasification chamber, which will give a higher syngas percentage due to the separation of gas produced in each chamber. To maximize the efficiency, research on the hydrodynamics of the DFB system needs to be carried out as this can improve the heat transfer and mass transfer in the system. In this study, experiments using a Dual Fluidized Bed cold model was carried out to analyze the effect of particle size from 0.3mm to 1mm, CFB gas superficial velocity from 3m/s to 4.5m/s, and BFB bed height from 20cm to 35cm to the pressure profile and the bed material mass flow rate. The bed material used in this study is silica sand as this material is the commonly used material in a gasification process due to its inert behavior The results showed that as the particle size increases, the flowing pattern will differ, the mass flow rate was decreased, and the pressure profile of each particle size was changed, where it can be used to determine the dense and lean region of each particle size used. The increase in Circulating Fluidized Bed gas superficial velocity (VairCFB) increases the pressure within the lower region of CFB, while an excess in superficial velocity increases the pressure at the upper region of CFB while decreases the pressure generated at the bottom. While the increase of Bubbling Fluidized Bed’s bed height (hBFB) increases the solid circulation mass flow rate, but an excess in bed inventory negatively impacts the system as this decreases the mass flow rate. From this results, it is possible to determine the optimum parameter used for this DFB cold model design is to use 0.3 mm silica sand particle size with 3.5 m/s VairCFB and 30cm hBFB as this configuration gives better solid circulation and it prevents too much particle from being lost from the system. The contribution of this research is that the results from each experiments can be used to decide good operating parameters and perhaps a better DFB design.
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