Case photos of gray agglomerated fluidized bed gasifier
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The gray agglomeration gasification technology was developed by the Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences. It is a domestically produced fluidized bed gasifier. What sets it apart from other fluidized bed gasifiers is that, in general, such gasifiers require a high carbon-to-ash ratio in the bed material, as well as uniform mixing of carbon, in order to maintain stable conditions free from slag formation. Therefore, the carbon content of the ash discharged from the furnace bottom is relatively high (15%-20%). To address these issues, an ash discharging method based on ash agglomeration (also known as ash compaction or ash cohesion) has been proposed. The specific approach is to create localized high-temperature areas within the fluidized bed layer, causing the ash particles to soften (above ST) without melting (below FT), thereby gaining a certain degree of viscosity. These particles then collide with each other and stick together to form ash balls with a low carbon content. When these ash balls grow to a size such that they can no longer be held up by the upward airflow, they separate from the coal powder and fall into the ash hopper at the bottom of the furnace, from where they are removed from the furnace. This reduces the carbon content in the ash (which can reach 5%-10%), thereby improving the carbon utilization efficiency in the gasification process. It seems that temperature control and industrial agglomeration are the challenges, but fluidized beds have low requirements regarding the moisture content of the feed material; therefore, they could be considered in areas where lignite resources are abundant.
“However, the fluidized bed does not have strict requirements regarding the moisture content of the feedstock, so it is an option to consider in areas where lignite resources are abundant. Our gasification furnace, on the other hand, has quite strict requirements regarding external water!
Lignite can also be processed using ash fusion; we are launching this project and it will go into operation by the end of the year. Where are the photos the original poster mentioned? I’m at the only site of this furnace in the country.....
The ash agglomeration fluidized bed gasification technology utilizes the principle of jets to incorporate an ash agglomeration and separation device at the bottom of the fluidized bed, thereby creating localized high-temperature areas within the bed. This allows the ash to aggregate into balls, and the difference in weight is used to separate these ash aggregates from the semi-coke. Under conditions without slag formation, low-carbon ash can be continuously and selectively removed. At present, the pressurized ash fusion gasification industrial unit developed by the Shanxi Coal Chemical Research Institute of the Chinese Academy of Sciences and the Shanxi Province Powder Coal Gasification Engineering Research Center has been successfully applied in the 100,000-ton/year coal-based MTG synthetic oil demonstration project of Jincheng Coal Group’s Tianxi Coal-to-Oil Branch. This project is equipped with 6 ash fusion gasifiers (5 in operation and 1 as backup); the operating pressure of the gasifiers is 0.6 MPa, they can process 1,600 tons of Jincheng anthracite per day, and the dry gas output is 125,000 Nm3/h – this capacity is sufficient to support a 300,000-ton/year synthetic methanol production facility.
Reply to rhinocao: Yes, one of the main problems we are facing at present is the difficulty in transporting materials before they enter the furnace due to high external water levels.