Modelling and Simulation of the Freezing Systems and Heat Pumps Using Unisim ® Design C
Abstract—The paper describes the modeling and simulation of the heat pumps domain processes. The main objective of the study is the use of the heat pump in propene–propane distillation processes. The modeling and simulation instrument is the Unisim® Design simulator. The paper is structured in three parts: An overview of the compressing gases, the modeling and simulation of the freezing systems, and the modeling and simulation of the heat pumps. For each of these systems, there are presented the Unisim® Design simulation diagrams, the input–output system structure and the numerical results. Future studies will consider modeling and simulation of the propene–propane distillation process with heat pump.
Simulation of Gas Dehydration Plants Safe Operation in Chemical Industry
This article describes a study of the dynamic behavior of a gas dehydration plant that uses triethylene glycol as sorbent agent. The gas dehydration technology in these plants benefits from the high capacity of triethylene – glycol to absorb water from gas. After desorption the hygroscopic qualities of the agent return to the initial state of unsaturation. The authors used the software package HYSYS v3.2® to simulate this process. The main cases refer only to the process safety in operation and the various situations that may occur during this process.
Active Compressor Surge Control Using Piston Actuation
A novel approach to active surge control in compressors using piston actuation is presented. Two control laws are compared in order to evaluate the feasibility of implementing the concept. The first control law is a nonlinear feedback control derived by using backstepping and the second one is a linear feedback control derived by analyzing the eigenvalues of the linearized system around the operating point. The nonlinear feedback control law makes the closed loop system globally asymptotically stable (GAS) and uses full states feedback. The linear feedback control is only using feedback from plenum pressure and piston velocity and the removal of the mass flow feedback is advantageous for implementation. The closed loop system with the linear feedback control is locally asymptotically stable around the operating point. Simulations show that both controllers are capable of stabilizing surge.© 2011 ASME