Science should drive policies and regulations to ensure a sustainable(environmentally,socially,and economically)green transition to a Net-Zero/Net-Negative circular economy.Since 2015,which saw COP21 in Paris,Net Zero...Science should drive policies and regulations to ensure a sustainable(environmentally,socially,and economically)green transition to a Net-Zero/Net-Negative circular economy.Since 2015,which saw COP21 in Paris,Net Zero has been a global target that must be rapidly accompanied by a Net Negative strategy to mitigate climate change.Accordingly,biochar’s role as a durable carbon removal method is gaining attention and increasing.In this work,we discuss the durability of the carbon in biochar and the need for analytical techniques to support stakeholders on a project level.The different ecologically relevant groups of carbon forms contained in biochar are presented,and possible project-based methods to assess the quality and durability of the product versus the regulatory requirements for the permanence of carbon removals are summarized.Biochar is today one of the CDR technologies with the highest technology readiness level(TRL 8-9)that can ensure permanent removals for time frames relevant to climate change mitigation projects,combined with co-benefits that are gaining relevance in terms of mitigating climate impacts in agricultural soils.展开更多
Experiments were conducted on a lab-scale fluidized bed to study the distribution of liquid ethanol injected into fluidized catalyst particles. Electrical capacitance measurements were used to study the liquid distrib...Experiments were conducted on a lab-scale fluidized bed to study the distribution of liquid ethanol injected into fluidized catalyst particles. Electrical capacitance measurements were used to study the liquid distribution inside the bed, and a new method was developed to determine the liquid content inside fluidized beds of fluid catalytic cracking particles. The results shed light on the complex liquid injection region and reveal the strong effect of superficial gas velocity on liquid distribution inside the fluidized bed, which is also affected by the imbibition of liquid inside particle pores. Particle internal porosity was found to play a major role when the changing mass of liquid in the bed was monitored. The results also showed that the duration of liquid injection affected liquid-solid contact inside the bed and that liouid-solid mixin~ was not homogeneous durin~ the limited liouid injection time.展开更多
The radioactive particle tracking technique was used to study the effect of internal ring baffles on wet agglomerate motion inside a cold flow recirculating fluidized bed. The study found that using such a baffle on i...The radioactive particle tracking technique was used to study the effect of internal ring baffles on wet agglomerate motion inside a cold flow recirculating fluidized bed. The study found that using such a baffle on its own or above the regular sheds helps reduce the fouling of the stripper section by increasing the residence time that the agglomerates spend above the baffle, thereby reducing the release of the vapors below the baffles that cause fouling of the sheds. Adding down-comers, or flux tubes, to the ring baffles degrades the performance of the baffles, Reducing the length of the flux tubes, so that they do not reach the bottom of the baffle lip results in a further degradation in baffle performance.展开更多
In processes such as Fluid Coking^(™),agglomerate formation should be minimized since it reduces the yield of valuable products,and degrades operability because of the fouling of internals.An experimental model,consis...In processes such as Fluid Coking^(™),agglomerate formation should be minimized since it reduces the yield of valuable products,and degrades operability because of the fouling of internals.An experimental model,consisting of an aqueous solution of gum arabic with a dye,has been successfully developed to simulate the formation of agglomerates in the Fluid Coking^(™)process,where bitumen is sprayed into a fluidized bed of coke particles The particles wetted by a spray could be predicted by assuming that all the particles in the wake of bubbles formed from the tip of the spray jet have been wetted by the injected liquid.The transfer of liquid from particles wetted with the spray to dry bed particles was relatively ineffective,as the number of wet particles increased by only 50%.With successive liquid injections,the proportion of the liquid trapped in agglomerates increases in latter injections:large agglomerates from earlier injections accumulate above the grid and are carried by gas bubbles into the spray jet cavity,where they seed fresh agglomerates.展开更多
文摘Science should drive policies and regulations to ensure a sustainable(environmentally,socially,and economically)green transition to a Net-Zero/Net-Negative circular economy.Since 2015,which saw COP21 in Paris,Net Zero has been a global target that must be rapidly accompanied by a Net Negative strategy to mitigate climate change.Accordingly,biochar’s role as a durable carbon removal method is gaining attention and increasing.In this work,we discuss the durability of the carbon in biochar and the need for analytical techniques to support stakeholders on a project level.The different ecologically relevant groups of carbon forms contained in biochar are presented,and possible project-based methods to assess the quality and durability of the product versus the regulatory requirements for the permanence of carbon removals are summarized.Biochar is today one of the CDR technologies with the highest technology readiness level(TRL 8-9)that can ensure permanent removals for time frames relevant to climate change mitigation projects,combined with co-benefits that are gaining relevance in terms of mitigating climate impacts in agricultural soils.
文摘Experiments were conducted on a lab-scale fluidized bed to study the distribution of liquid ethanol injected into fluidized catalyst particles. Electrical capacitance measurements were used to study the liquid distribution inside the bed, and a new method was developed to determine the liquid content inside fluidized beds of fluid catalytic cracking particles. The results shed light on the complex liquid injection region and reveal the strong effect of superficial gas velocity on liquid distribution inside the fluidized bed, which is also affected by the imbibition of liquid inside particle pores. Particle internal porosity was found to play a major role when the changing mass of liquid in the bed was monitored. The results also showed that the duration of liquid injection affected liquid-solid contact inside the bed and that liouid-solid mixin~ was not homogeneous durin~ the limited liouid injection time.
文摘The radioactive particle tracking technique was used to study the effect of internal ring baffles on wet agglomerate motion inside a cold flow recirculating fluidized bed. The study found that using such a baffle on its own or above the regular sheds helps reduce the fouling of the stripper section by increasing the residence time that the agglomerates spend above the baffle, thereby reducing the release of the vapors below the baffles that cause fouling of the sheds. Adding down-comers, or flux tubes, to the ring baffles degrades the performance of the baffles, Reducing the length of the flux tubes, so that they do not reach the bottom of the baffle lip results in a further degradation in baffle performance.
基金The authors thank the entire group at the Institute for Chemicals and Fuels from Alternative Resources(ICFAR).Financial support from the NSERC/Syncrude/ExxonMobil Industrial Research Chair in Fluid Coking Technologies is gratefully acknowledged.
文摘In processes such as Fluid Coking^(™),agglomerate formation should be minimized since it reduces the yield of valuable products,and degrades operability because of the fouling of internals.An experimental model,consisting of an aqueous solution of gum arabic with a dye,has been successfully developed to simulate the formation of agglomerates in the Fluid Coking^(™)process,where bitumen is sprayed into a fluidized bed of coke particles The particles wetted by a spray could be predicted by assuming that all the particles in the wake of bubbles formed from the tip of the spray jet have been wetted by the injected liquid.The transfer of liquid from particles wetted with the spray to dry bed particles was relatively ineffective,as the number of wet particles increased by only 50%.With successive liquid injections,the proportion of the liquid trapped in agglomerates increases in latter injections:large agglomerates from earlier injections accumulate above the grid and are carried by gas bubbles into the spray jet cavity,where they seed fresh agglomerates.
