The ammonia synthesis reactor is the core unit in the whole ammonia synthesis production. The ammonia concentration at the ammonia converter outlet is a significant process variable, which reflects directly the produc...The ammonia synthesis reactor is the core unit in the whole ammonia synthesis production. The ammonia concentration at the ammonia converter outlet is a significant process variable, which reflects directly the production efficiency. However, it is hard to be measured reliably online in real applications. In this paper, a soft sensor based on BP neural network (BPNN) is applied to estimate the ammonia concentration. A modified group search optimization with nearest neighborhood (GSO-NH) is proposed to optimize the weights and thresholds of BPNN. GSO-NH is integrated with BPNN to build a soft sensor model. Finally, the soft sensor model based on BPNN and GSO-NH (GSO-NH-NN) is used to infer the outlet ammonia concentration in a real-world application. Three other modeling methods are applied for comparison with GSO-NH-NN. The results show that the soft sensor based on GSO-NH-NN has a good prediction performance with high accuracy. Moreover, the GSO-NH-NN also provides good generalization ability to other modeling problems in ammonia synthesis production.展开更多
A new type of multi-tube column, in which a novel internal-structure is installed in the bed of random packing, has been invented. The internal-structure reduces the hydraulic radius of the column and adjusts the gas/...A new type of multi-tube column, in which a novel internal-structure is installed in the bed of random packing, has been invented. The internal-structure reduces the hydraulic radius of the column and adjusts the gas/liquid flow so that the liquid maldistribution is greatly abated. A mathematical model with boundary conditions based on close-open mechanism at the internal-structure was established to study the hydraulic behavior of such a column and experiments were carded out to verify the applicability of the model. Predictions from the model agreed well with experimental results. The optimal ratio of the hydraulic diameter of the new multi-tube column to the packing element diameter is found to be 17.5 to 23.3 by employing the optimization method of nonlinear programming. And this new type of multi-tube column opens a new way for random packing columns to be scaled up for industry.展开更多
基金Supported by the National Natural Science Foundation of China (61074079)Shanghai Leading Academic Discipline Project(B504)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China (20100074120010)the Natural Science Foundation of Shanghai City (11ZR1409700)
文摘The ammonia synthesis reactor is the core unit in the whole ammonia synthesis production. The ammonia concentration at the ammonia converter outlet is a significant process variable, which reflects directly the production efficiency. However, it is hard to be measured reliably online in real applications. In this paper, a soft sensor based on BP neural network (BPNN) is applied to estimate the ammonia concentration. A modified group search optimization with nearest neighborhood (GSO-NH) is proposed to optimize the weights and thresholds of BPNN. GSO-NH is integrated with BPNN to build a soft sensor model. Finally, the soft sensor model based on BPNN and GSO-NH (GSO-NH-NN) is used to infer the outlet ammonia concentration in a real-world application. Three other modeling methods are applied for comparison with GSO-NH-NN. The results show that the soft sensor based on GSO-NH-NN has a good prediction performance with high accuracy. Moreover, the GSO-NH-NN also provides good generalization ability to other modeling problems in ammonia synthesis production.
文摘A new type of multi-tube column, in which a novel internal-structure is installed in the bed of random packing, has been invented. The internal-structure reduces the hydraulic radius of the column and adjusts the gas/liquid flow so that the liquid maldistribution is greatly abated. A mathematical model with boundary conditions based on close-open mechanism at the internal-structure was established to study the hydraulic behavior of such a column and experiments were carded out to verify the applicability of the model. Predictions from the model agreed well with experimental results. The optimal ratio of the hydraulic diameter of the new multi-tube column to the packing element diameter is found to be 17.5 to 23.3 by employing the optimization method of nonlinear programming. And this new type of multi-tube column opens a new way for random packing columns to be scaled up for industry.
