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Air Reactor (air + reactor)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

A novel dual circulating fluidized bed system for chemical looping processes

AICHE JOURNAL, Issue 12 2009
Tobias Pröll
Abstract A fluidized bed system combining two circulating fluidized bed reactors is proposed and investigated for chemical looping combustion. Direct hydraulic communication of the two circulating fluidized bed reactors via a fluidized loop seal allows for high rates of global solids circulation and results in a stable solids distribution in the system. A 120 kW fuel power bench scale unit was designed, built, and operated. Experimental results are presented for natural gas as fuel using a nickel-based oxygen carrier. No carbon was lost to the air reactor under any conditions operated. It is shown from fuel power variations that a turbulent/fast fluidized bed regime in the fuel reactor is advantageous. Despite the relatively low riser heights (air reactor: 4.1 m, fuel reactor: 3.0 m), high CH4 conversion and CO2 yield of up to 98% and 94%, respectively, can be reported for the material tested. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Dynamic optimization of the methylmethacrylate cell-cast process for plastic sheet production

AICHE JOURNAL, Issue 6 2009
Martín Rivera-Toledo
Abstract Traditionally, the methylmethacrylate (MMA) polymerization reaction process for plastic sheet production has been carried out using warming baths. However, it has been observed that the manufactured polymer tends to feature poor homogeneity characteristics measured in terms of properties like molecular weight distribution. Nonhomogeneous polymer properties should be avoided because they give rise to a product with undesired wide quality characteristics. To improve homogeneity properties force-circulated warm air reactors have been proposed, such reactors are normally operated under isothermal air temperature conditions. However, we demonstrate that dynamic optimal warming temperature profiles lead to a polymer sheet with better homogeneity characteristics, especially when compared against simple isothermal operating policies. In this work, the dynamic optimization of a heating and polymerization reaction process for plastic sheet production in a force-circulated warm air reactor is addressed. The optimization formulation is based on the dynamic representation of the two-directional heating and reaction process taking place within the system, and includes kinetic equations for the bulk free radical polymerization reactions of MMA. The mathematical model is cast as a time dependent partial differential equation (PDE) system, the optimal heating profile calculation turns out to be a dynamic optimization problem embedded in a distributed parameter system. A simultaneous optimization approach is selected to solve the dynamic optimization problem. Trough full discretization of all decision variables, a nonlinear programming (NLP) model is obtained and solved by using the IPOPT optimization solver. The results are presented about the dynamic optimization for two plastic sheets of different thickness and compared them against simple operating policies. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Nickel- and Copper-Based Oxygen Carriers for Chemical Looping Combustion

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2009
A. Hoteit
Abstract Chemical looping combustion (CLC) is a combustion process in which the different fuels can be burnt with inherent separation of CO2. A CLC system has two interconnected reactors named as fuel and air reactor. In the fuel reactor, metal oxides supply oxygen for the combustion of the gaseous fuel, and the metal oxides are regenerated (oxidized) with air in the air reactor. The feasibility of a CLC system greatly depends on the selection of appropriate metal oxides as oxygen carriers. In the present study, NiO/NiAl2O4 and Cu0.95Fe1.05AlO4 were tested experimentally in a fluidized-bed reactor as a function of number of oxidation-reduction cycles, temperature and effect of steam mixed with methane as a fuel. A 30-MWfuel CLC system was simulated for the combustion of biogas, syngas and methane on the basis of the experimental results. [source]

Dynamic optimization of the methylmethacrylate cell-cast process for plastic sheet production

AICHE JOURNAL, Issue 6 2009
Martín Rivera-Toledo
Abstract Traditionally, the methylmethacrylate (MMA) polymerization reaction process for plastic sheet production has been carried out using warming baths. However, it has been observed that the manufactured polymer tends to feature poor homogeneity characteristics measured in terms of properties like molecular weight distribution. Nonhomogeneous polymer properties should be avoided because they give rise to a product with undesired wide quality characteristics. To improve homogeneity properties force-circulated warm air reactors have been proposed, such reactors are normally operated under isothermal air temperature conditions. However, we demonstrate that dynamic optimal warming temperature profiles lead to a polymer sheet with better homogeneity characteristics, especially when compared against simple isothermal operating policies. In this work, the dynamic optimization of a heating and polymerization reaction process for plastic sheet production in a force-circulated warm air reactor is addressed. The optimization formulation is based on the dynamic representation of the two-directional heating and reaction process taking place within the system, and includes kinetic equations for the bulk free radical polymerization reactions of MMA. The mathematical model is cast as a time dependent partial differential equation (PDE) system, the optimal heating profile calculation turns out to be a dynamic optimization problem embedded in a distributed parameter system. A simultaneous optimization approach is selected to solve the dynamic optimization problem. Trough full discretization of all decision variables, a nonlinear programming (NLP) model is obtained and solved by using the IPOPT optimization solver. The results are presented about the dynamic optimization for two plastic sheets of different thickness and compared them against simple operating policies. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]