This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safe...This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safety.The ash fusion characteristics of Qinghai bituminous coal together with Fushun,Xinghua and Laoheishan oil shales(and their respective blends)were quantified using a novel picture analysis and graphing method,which incorporates conventional ash fusion study,dilatometry and sintering strength test,in a CO/CO_(2)atmosphere.This imagebased characterisation method was used to monitor and quantify the complete melting behaviour of ash samples from room temperature to 1520℃.The impacts of blending on compositional changes during heating were determined experimentally via Xray diffraction and validated computationally using FactSage.Results showed that the melting point of Qinghai coal ash to be the lowest at 1116℃,but would increase up to 1208℃,1161℃and 1160℃with the addition of 30%50%of Laoheishan,Fushun,and Xinghua oil shales,respectively.The formation of highmelting anorthite and mullite structures inhibits the formation of lowmelting hercynite.However,the sintering point of Qinghai coal ash was seen to decrease from 1005℃to 855℃,834℃,and 819℃in the same blends due to the formation of lowmelting aluminosilicate.Results also showed that blending directly influences the sintering strength during the various stages of melting.The key finding from this study is that it is possible to mitigate against the severe ash slagging and fouling issue arising from high calcium and iron coals by cogasification with a high silicaalumina oil shale.Moreover,blending coals with oil shales can also modify the ash melting behaviour of fuels to create the optimal ash chemistry that meets the design specification of the gasifier,without adversely affecting thermal performance.展开更多
Continuous hydrothermal synthesis was highlighted in a recent review as an enabling technology for the production of nanoparticles. In recent years, it has been shown to be a suitable reaction medium for the synthesis...Continuous hydrothermal synthesis was highlighted in a recent review as an enabling technology for the production of nanoparticles. In recent years, it has been shown to be a suitable reaction medium for the synthesis of a wide range of nanomaterials. Many single and complex nanomaterials such as metals, metal oxides, doped oxides, carbonates, sulfides, hydroxides, phosphates, and metal organic frameworks can be formed using continuous hydrothermal synthesis techniques. This work presents a methodology to characterize continuous hydrothermal flow systems both experimentally and numerically, and to determine the scalability of a counter current supercritical water reactor for the large scale production （〉1,000 T-year-1） of nanomaterials. Experiments were performed using a purpose-built continuous flow rig, featuring an injection loop on a metal salt feed line, which allowed the injection of a chromophoric tracer. At the system outlet, the tracer was detected using UV/Vis absorption, which could be used to measure the residence time distribution within the reactor volume. Computational fluid dynamics （CFD） calculations were also conducted using a modeled geometry to represent the experimental apparatus. The performance of the CFD model was tested against experimental data, verifying that the CFD model accurately predicted the nucleation and growth of the nanomaterials inside the reactor.展开更多
基金The authors gratefully express gratitude to all parties which have contributed towards the success of this project,both financially and technically,especially the S&T Innovation 2025 Major Special Programme(grant number 2018B10022)the Ningbo Natural Science Foundation Programme(grant number 2018A610069)+1 种基金funded by the Ningbo Science and Technology Bureau,China,as well as the Industrial Technology Innovation and Industrialization of Science and Technology Project,China(grant number 2014A35001-2)the UNNC FoSE Faculty Inspiration Grant,China.The Zhejiang Provincial Department of Science and Technology is also acknowledged for this research under its Provincial Key Laboratory Programme(2020E10018).
文摘This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safety.The ash fusion characteristics of Qinghai bituminous coal together with Fushun,Xinghua and Laoheishan oil shales(and their respective blends)were quantified using a novel picture analysis and graphing method,which incorporates conventional ash fusion study,dilatometry and sintering strength test,in a CO/CO_(2)atmosphere.This imagebased characterisation method was used to monitor and quantify the complete melting behaviour of ash samples from room temperature to 1520℃.The impacts of blending on compositional changes during heating were determined experimentally via Xray diffraction and validated computationally using FactSage.Results showed that the melting point of Qinghai coal ash to be the lowest at 1116℃,but would increase up to 1208℃,1161℃and 1160℃with the addition of 30%50%of Laoheishan,Fushun,and Xinghua oil shales,respectively.The formation of highmelting anorthite and mullite structures inhibits the formation of lowmelting hercynite.However,the sintering point of Qinghai coal ash was seen to decrease from 1005℃to 855℃,834℃,and 819℃in the same blends due to the formation of lowmelting aluminosilicate.Results also showed that blending directly influences the sintering strength during the various stages of melting.The key finding from this study is that it is possible to mitigate against the severe ash slagging and fouling issue arising from high calcium and iron coals by cogasification with a high silicaalumina oil shale.Moreover,blending coals with oil shales can also modify the ash melting behaviour of fuels to create the optimal ash chemistry that meets the design specification of the gasifier,without adversely affecting thermal performance.
文摘Continuous hydrothermal synthesis was highlighted in a recent review as an enabling technology for the production of nanoparticles. In recent years, it has been shown to be a suitable reaction medium for the synthesis of a wide range of nanomaterials. Many single and complex nanomaterials such as metals, metal oxides, doped oxides, carbonates, sulfides, hydroxides, phosphates, and metal organic frameworks can be formed using continuous hydrothermal synthesis techniques. This work presents a methodology to characterize continuous hydrothermal flow systems both experimentally and numerically, and to determine the scalability of a counter current supercritical water reactor for the large scale production （〉1,000 T-year-1） of nanomaterials. Experiments were performed using a purpose-built continuous flow rig, featuring an injection loop on a metal salt feed line, which allowed the injection of a chromophoric tracer. At the system outlet, the tracer was detected using UV/Vis absorption, which could be used to measure the residence time distribution within the reactor volume. Computational fluid dynamics （CFD） calculations were also conducted using a modeled geometry to represent the experimental apparatus. The performance of the CFD model was tested against experimental data, verifying that the CFD model accurately predicted the nucleation and growth of the nanomaterials inside the reactor.
