In this paper,an online tracking simulation system for the 660 MW ultra-supercritical circulating fluidized bed(USCFB)boiler is established,and a tracking simulation test is conducted for the cold start-up process of ...In this paper,an online tracking simulation system for the 660 MW ultra-supercritical circulating fluidized bed(USCFB)boiler is established,and a tracking simulation test is conducted for the cold start-up process of the boiler.The system comprises two parts:the USCFB boiler model and a tracking mechanism based on sliding mode control algorithm.The USCFB boiler model includes a water-steam system,an air-flue gas system,a material supply system,and an ash circulation system.The online tracking simulation system receives the same control signal as the plant and runs synchronously in digital space.The tracking mechanism updates model parameters to eliminate deviations between simulation values and measured values.The SMC-based multi-input,multi-output algorithm is based on a state-space model,providing two distinct advantages.Firstly,it enables more efficient elimination of deviations;secondly,it exhibits robustness against uncertainties associated with simulation model behavior and measurement noise.Finally,this paper conducts tracking simulation research on the cold start-up process of the boiler.展开更多
The cold start-up of the PEMFC(proton exchange membrane fuel cell)stack from sub-zero temperature is considered one of the significant obstacles to its expansive commercial applications.In the cold start-up process,wi...The cold start-up of the PEMFC(proton exchange membrane fuel cell)stack from sub-zero temperature is considered one of the significant obstacles to its expansive commercial applications.In the cold start-up process,with the progress of hydrogen/oxygen chemical reaction,the produced water will freeze into ice,occupying the pores of the porous electrode,thus leading to a rapid deterioration of output performance and even making the cold start-up fail.In this work,a one-dimensional numerical model is adopted to study a cold start-up process of the PMEFC stack starting from-30℃.The stepwise-changed current loading mode is employed in the process.An assisted preheating method is used to explore an optimal operating condition for a successful cold start-up.The numerical results are validated by comparing the numerical result with the experimental data in reference,and they agree with the experimental data very well.The results show that the optimal heating power in the studied range is 100 W.As the initial current slope increased,the current peak value increased,but the cold start-up process failed.Also,the start-up time and ice volume fraction are highly dependent on the initial current slope.The optimal initial current slope is 0.7 A/s.Besides,a higher initial current slope will cause a significant inner ohmic resistance.The resistance of CLa(catalyst layer of the anode)is the key and primary part of the total ohmic resistance.The details of the research and the analyzed results will help design the cold start-up strategy for the PEMFC stack start-up from-30℃.展开更多
文摘In this paper,an online tracking simulation system for the 660 MW ultra-supercritical circulating fluidized bed(USCFB)boiler is established,and a tracking simulation test is conducted for the cold start-up process of the boiler.The system comprises two parts:the USCFB boiler model and a tracking mechanism based on sliding mode control algorithm.The USCFB boiler model includes a water-steam system,an air-flue gas system,a material supply system,and an ash circulation system.The online tracking simulation system receives the same control signal as the plant and runs synchronously in digital space.The tracking mechanism updates model parameters to eliminate deviations between simulation values and measured values.The SMC-based multi-input,multi-output algorithm is based on a state-space model,providing two distinct advantages.Firstly,it enables more efficient elimination of deviations;secondly,it exhibits robustness against uncertainties associated with simulation model behavior and measurement noise.Finally,this paper conducts tracking simulation research on the cold start-up process of the boiler.
基金supported by the key project of NNSFC(51836005)the International Exchange Cooperation Project of NSFC-STINT(5191153015)+2 种基金the Basic research Project of Shaanxi Province(2019ZDXM3-01)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(51721004)111 Project(B16038)。
文摘The cold start-up of the PEMFC(proton exchange membrane fuel cell)stack from sub-zero temperature is considered one of the significant obstacles to its expansive commercial applications.In the cold start-up process,with the progress of hydrogen/oxygen chemical reaction,the produced water will freeze into ice,occupying the pores of the porous electrode,thus leading to a rapid deterioration of output performance and even making the cold start-up fail.In this work,a one-dimensional numerical model is adopted to study a cold start-up process of the PMEFC stack starting from-30℃.The stepwise-changed current loading mode is employed in the process.An assisted preheating method is used to explore an optimal operating condition for a successful cold start-up.The numerical results are validated by comparing the numerical result with the experimental data in reference,and they agree with the experimental data very well.The results show that the optimal heating power in the studied range is 100 W.As the initial current slope increased,the current peak value increased,but the cold start-up process failed.Also,the start-up time and ice volume fraction are highly dependent on the initial current slope.The optimal initial current slope is 0.7 A/s.Besides,a higher initial current slope will cause a significant inner ohmic resistance.The resistance of CLa(catalyst layer of the anode)is the key and primary part of the total ohmic resistance.The details of the research and the analyzed results will help design the cold start-up strategy for the PEMFC stack start-up from-30℃.
