Yang Yongrong

Estimation of rate constants for polymerization based on Monte Carlo simulation

The application of Monte Carlo method in estimating rate constants for polymerization was described. A general program for Monte Carlo simulation was determined first according to the elementary reactions, after which the rate constants could be automatically adjusted and optimized through comparing of experimental and simulated data with an error expression that meeted a given minimum criterion. Such a process made the rate constants to be estimated without kinetic model in advance. The technique was applied to estimate the rate constants of the bulk polymerization of styrene catalyzed by the rare earth catalyst. The estimated results showed the Monte Carlo method was feasible and effective for estimating rate constants in polymerization engineering.

Robust Engineering Strategy for Solving Optimization Problems of Refinery Hydrogen System

Abstract Hydrogen is an important resource to upgrade refinery products. It is the second largest cost of refineries. Optimal scheduling of the hydrogen system will cut down on the energy cost and reduce carbon emissions in refineries. However, due to the mutability of the hydrogen generation and consumption, current scheduling methods may cause instability problems. This paper presents a robust engineering strategy that has been applied to hydrogen pipeline networks of a large-scale refinery. The implementation strategy involves four steps: model precision validation, solving efficiency validation, effect validation, and on field validation. The proposed strategy ensures the feasibility, necessity, and effectiveness of the previously developed mathematical model and solution approach.

Study on the nature of pressure signals in a bubbling fluidized bed

In this study on the nature of pressure signals generated by a deterministic or stochastic process in a bubbling fluidized bed, pressure fluctuation measurements were carried out in a 300-mm-diamet column at 0.090 m and 0.40 m above the distributor for different gas velocities. The method of detecting deterministic dynamic underlying pressure signals is proposed on the basis of predictability of pressure fluctuations. The deterministic nature of dynamics in fluidizing system was verified. The deterministic level of dynamics in fluidizing system was analyzed for different locations of pressure measurements and different gas velocities.