This study proposes a method of interactive plant simulation modeling which delivers the online simulated results to the field operators and induces them to take proper actions in the case of pre-identified accident s...This study proposes a method of interactive plant simulation modeling which delivers the online simulated results to the field operators and induces them to take proper actions in the case of pre-identified accident scenarios in a chemical plant. The developed model integrates the real-time process dynamic simulation with 3DCFD accident simulation in a designed interface using object linking and embedding technology so that it can convey to trainees the online information of the accident which is not available in existing operator training systems.The model encompasses the whole process of data transfer till the end of the training at which a trainee operates an emergency shutdown system in a programmed model. In this work, an overall scenario is simulated which is from an abnormal increase in the main valve discharge（second）pressure due to valve malfunction to accidental gas release through the crack of a pressure recorder, and the magnitude of the accident with respect to the lead time of each trainee＇s emergency response is analyzed. The model can improve the effectiveness of the operator training system through interactively linking the trainee actions with the simulation model resulting in different accident scenarios with respect to each trainee＇s competence when facing an accident.展开更多
The energy minimization multi-scale(EMMS)is a heterogeneous drag model widely used to simulate gas-solid fluidized beds.In this work,we conducted computational fluid dynamics simulations of a gas-solid fluidized bed f...The energy minimization multi-scale(EMMS)is a heterogeneous drag model widely used to simulate gas-solid fluidized beds.In this work,we conducted computational fluid dynamics simulations of a gas-solid fluidized bed for Geldart B particles to compare the EMMS with the homogeneous Gidaspow drag model.The results from both the homogeneous and heterogeneous drag models were compared with literature experimental data on pressure drop and bed expansion.There was no noticeable difference in predicted bed characteristics in the slugging regime.However,in the turbulent regime,the EMMS model predicted slightly lower bed expansion than did the Gidaspow model.We evaluated the effects of solid-solid and solid-wall interaction parameters by varying the restitution and specularity coefficients.Bed expansion increases by a factor of 1.05-1.08 when the restitution coefficient increases from 0.9 to 0.99.The models predict a higher solid volume fraction and higher solid downflow velocity near the wall for a low specularity coefficient of 0.01 or 0.When we considered solid phases of different sizes to model polydisperity,the simulation predicted vertical segregation of 300,350,and 400μm in the fluidized region due to gravity.Furthermore,the drag models made similar predictions in bad characteristics from cold model simulation ofa polysilicon fluidized-bed reactor,although there was very little vertical segregation of solid particles for this case.展开更多
基金supported by a Grant No. (14IFIP-B085984-03) from Smart Civil Infrastructure Research Program funded by the Korea Government Ministry of Land,Infrastructure and Transport (MOLIT) and The Korea Agency for Infrastructure Technology Advancement(KAIA)by Korea Ministry of Environment (MOE) as ‘the Chemical Accident Prevention Technology Development Project’ (No. 2015001950003)
文摘This study proposes a method of interactive plant simulation modeling which delivers the online simulated results to the field operators and induces them to take proper actions in the case of pre-identified accident scenarios in a chemical plant. The developed model integrates the real-time process dynamic simulation with 3DCFD accident simulation in a designed interface using object linking and embedding technology so that it can convey to trainees the online information of the accident which is not available in existing operator training systems.The model encompasses the whole process of data transfer till the end of the training at which a trainee operates an emergency shutdown system in a programmed model. In this work, an overall scenario is simulated which is from an abnormal increase in the main valve discharge（second）pressure due to valve malfunction to accidental gas release through the crack of a pressure recorder, and the magnitude of the accident with respect to the lead time of each trainee＇s emergency response is analyzed. The model can improve the effectiveness of the operator training system through interactively linking the trainee actions with the simulation model resulting in different accident scenarios with respect to each trainee＇s competence when facing an accident.
基金This research was supported by Korea Electric Power Corpora-tion(Grant number:R18XA06-14)supported by the Human Resources Development(No.20184030202070)of the Korea Insti-tute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korea government Ministry of Trade,Industry and Energy.
文摘The energy minimization multi-scale(EMMS)is a heterogeneous drag model widely used to simulate gas-solid fluidized beds.In this work,we conducted computational fluid dynamics simulations of a gas-solid fluidized bed for Geldart B particles to compare the EMMS with the homogeneous Gidaspow drag model.The results from both the homogeneous and heterogeneous drag models were compared with literature experimental data on pressure drop and bed expansion.There was no noticeable difference in predicted bed characteristics in the slugging regime.However,in the turbulent regime,the EMMS model predicted slightly lower bed expansion than did the Gidaspow model.We evaluated the effects of solid-solid and solid-wall interaction parameters by varying the restitution and specularity coefficients.Bed expansion increases by a factor of 1.05-1.08 when the restitution coefficient increases from 0.9 to 0.99.The models predict a higher solid volume fraction and higher solid downflow velocity near the wall for a low specularity coefficient of 0.01 or 0.When we considered solid phases of different sizes to model polydisperity,the simulation predicted vertical segregation of 300,350,and 400μm in the fluidized region due to gravity.Furthermore,the drag models made similar predictions in bad characteristics from cold model simulation ofa polysilicon fluidized-bed reactor,although there was very little vertical segregation of solid particles for this case.
