In manufacturing process, it is necessary to measure change in CSD (Crystal Size Distribution) with time accurately because CSD is one of the most important indices that evaluate quality of products. FBRM (Focused Bea...In manufacturing process, it is necessary to measure change in CSD (Crystal Size Distribution) with time accurately because CSD is one of the most important indices that evaluate quality of products. FBRM (Focused Beam Reflectance Measurement) can measure CLD (Chord Length Distribution) in line, but CLD is different from CSD because of principle of FBRM. However, if CSD is determined beforehand, CLD can be calculated from the CSD with statistical method. First, when crystal shape is defined from the characteristic crystal size, the matrix of each crystal shape which transforms CSD into CLD in a uniform manner is calculated with Monte Carlo analysis. Characteristic crystal size is added to the variables defining chord length in order to avoid complex integrals and apply the change in crystal shape with characteristic crystal size to the transforming matrix. Secondly, CSD and CLD are actually measured in suspension of acetaminophen in ethanol and suspension of L-arginine in water to demonstrate the validity of 2 matrices. Lastly, these matrices are multiplied by some simple CSD models to test the properties of these matrices and demonstrate the utility of this transformation.展开更多
Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM(focused beam reflectance measurement) and PVM(particle video microscope).The impacts of operating variab...Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM(focused beam reflectance measurement) and PVM(particle video microscope).The impacts of operating variables,such as seed size and loading,stirring speed,on induction period and secondary nucleation were investigated and explained by an adsorption model.The results show that seed surface area plays an important role in secondary nucleation,for more surface area has higher adsorption capacity and consumes more supersaturation on seed growth,thus restrains nucleation better.A method through comparison between pure breakage/attrition and nucleation process was put forward to distinguish attrition-induced and surface-induced nucleations quantitatively,which can reveal the contributions of different nucleation mechanisms.The nucleation processes in different conditions were studied,the principles and valuable experimental data were obtained for seeding approach primarily.FBRM and PVM are useful on-line apparatuses to facilitate seed selection and seeding optimization.展开更多
A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation...A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation degree and temperature.Magnetic field has nearly no impact on it,while the use of ultrasound reduces it obviously.The impacts of some impurities and additives on primary nucleation were investigated.It is found that the presence of Na2SO4,NH4Cl,(NH4)2SO4 and EDTA disodium prolongs induction period,whereas KCl,NaCl,NaBr and CH4N2O can decrease it.Many important parameters of primary nucleation are also obtained,as temperature goes up from 283 to 313 K,interfacial tension decreases from 44.8 to 41.5 mJ/m2,contact angle varies from 82.9o to 88.7o,nucleation order is between 5.0 and 5.4,surface entropy factors are all above 5,suggesting that the growth mechanism is a spiral growth.Besides,both the homogeneous and heterogeneous primary nucleations were monitored with on-line focused beam reflectance measurement.展开更多
Western Canada’s oil sands hold the third-largest hydrocarbon deposits in the world.Bitumen,a very heavy petroleum,is currently recovered by surface mining with warm water or in situ.Recovery processes that use organ...Western Canada’s oil sands hold the third-largest hydrocarbon deposits in the world.Bitumen,a very heavy petroleum,is currently recovered by surface mining with warm water or in situ.Recovery processes that use organic solvents are being developed to reduce water usage and tailings production.While solvent-based methods can effectively extract bitumen,removal of residual fine solids from diluted bitumen product(DBP)to meet the pipeline transport requirement of<0.5 wt%solids and water in DBP remains a major challenge.We propose a novel area of application of polymer flocculants for fine solids removal from DBP.In principle,polymer flocculants can be applied to help remove these residual solids in conjunction with physical separation processes to increase process effectiveness and energy efficiency.Several polymers are selected and screened for flocculation behavior using kaolinite suspended in DBP and toluene,as a model system.Focused beam reflectance measurements and force tensiometer techniques are used to determine flocculation and sedimentation in DBP.The observed flocculation and sedimentation rate enhancements indicate that the polymers tested have only minor effects,providing opportunities for advanced polymer development.These findings exemplify the challenges in identifying polymers that may be effective as flocculants in heavy petroleum media.展开更多
文摘In manufacturing process, it is necessary to measure change in CSD (Crystal Size Distribution) with time accurately because CSD is one of the most important indices that evaluate quality of products. FBRM (Focused Beam Reflectance Measurement) can measure CLD (Chord Length Distribution) in line, but CLD is different from CSD because of principle of FBRM. However, if CSD is determined beforehand, CLD can be calculated from the CSD with statistical method. First, when crystal shape is defined from the characteristic crystal size, the matrix of each crystal shape which transforms CSD into CLD in a uniform manner is calculated with Monte Carlo analysis. Characteristic crystal size is added to the variables defining chord length in order to avoid complex integrals and apply the change in crystal shape with characteristic crystal size to the transforming matrix. Secondly, CSD and CLD are actually measured in suspension of acetaminophen in ethanol and suspension of L-arginine in water to demonstrate the validity of 2 matrices. Lastly, these matrices are multiplied by some simple CSD models to test the properties of these matrices and demonstrate the utility of this transformation.
基金Supported by Shanghai Leading Academic Discipline Project (No.B506)Program for New Century Excellent Talents in University (No. NCET-08-0776)
文摘Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM(focused beam reflectance measurement) and PVM(particle video microscope).The impacts of operating variables,such as seed size and loading,stirring speed,on induction period and secondary nucleation were investigated and explained by an adsorption model.The results show that seed surface area plays an important role in secondary nucleation,for more surface area has higher adsorption capacity and consumes more supersaturation on seed growth,thus restrains nucleation better.A method through comparison between pure breakage/attrition and nucleation process was put forward to distinguish attrition-induced and surface-induced nucleations quantitatively,which can reveal the contributions of different nucleation mechanisms.The nucleation processes in different conditions were studied,the principles and valuable experimental data were obtained for seeding approach primarily.FBRM and PVM are useful on-line apparatuses to facilitate seed selection and seeding optimization.
基金Supported by Shanghai Leading Academic Discipline Project (No.B506)Program for New Century Excellent Talents in University (No. NCET-08-0776)
文摘A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation degree and temperature.Magnetic field has nearly no impact on it,while the use of ultrasound reduces it obviously.The impacts of some impurities and additives on primary nucleation were investigated.It is found that the presence of Na2SO4,NH4Cl,(NH4)2SO4 and EDTA disodium prolongs induction period,whereas KCl,NaCl,NaBr and CH4N2O can decrease it.Many important parameters of primary nucleation are also obtained,as temperature goes up from 283 to 313 K,interfacial tension decreases from 44.8 to 41.5 mJ/m2,contact angle varies from 82.9o to 88.7o,nucleation order is between 5.0 and 5.4,surface entropy factors are all above 5,suggesting that the growth mechanism is a spiral growth.Besides,both the homogeneous and heterogeneous primary nucleations were monitored with on-line focused beam reflectance measurement.
文摘Western Canada’s oil sands hold the third-largest hydrocarbon deposits in the world.Bitumen,a very heavy petroleum,is currently recovered by surface mining with warm water or in situ.Recovery processes that use organic solvents are being developed to reduce water usage and tailings production.While solvent-based methods can effectively extract bitumen,removal of residual fine solids from diluted bitumen product(DBP)to meet the pipeline transport requirement of<0.5 wt%solids and water in DBP remains a major challenge.We propose a novel area of application of polymer flocculants for fine solids removal from DBP.In principle,polymer flocculants can be applied to help remove these residual solids in conjunction with physical separation processes to increase process effectiveness and energy efficiency.Several polymers are selected and screened for flocculation behavior using kaolinite suspended in DBP and toluene,as a model system.Focused beam reflectance measurements and force tensiometer techniques are used to determine flocculation and sedimentation in DBP.The observed flocculation and sedimentation rate enhancements indicate that the polymers tested have only minor effects,providing opportunities for advanced polymer development.These findings exemplify the challenges in identifying polymers that may be effective as flocculants in heavy petroleum media.
