Chemical Engineering @ChemengFiles.Com

Distillation is undoubtedly the most important unit operation in chemical engineering. During design a significant effort is normally put into steady-state optimization of the column with respect to its size, feed location and reflux ratio. However, operating the column close to this optimal point requires reasonably tight control of the product compositions. This is usually not achieved in industrial practice due to stability problems. Improved strategies for distillation control offer a viable means for significant economic savings as compared to the existing ad hoc techniques. This thesis addresses robust control of distillation columns in the face of model-plant mismatch caused by model uncertainty, nonlinearity and changes in operating conditions. The robust control paradigm, introduced by Doyle and coworkers, is used as the basis for controller design and analysis. An important tool is the Structured Singular Value (SSV) which enables the evaluation of a plant's achievable control performance. This provides a consistent basis for comparing controllers and design alternatives. Achievable performance is also related to other commonly used measures such as the RGA and the condition number.

Distillation is undoubtedly the most important unit operation in chemical engineering. During design a significant effort is normally put into steady-state optimization of the column with respect to its size, feed location and reflux ratio. However, operating the column close to this optimal point requires reasonably tight control of the product compositions. This is usually not achieved in industrial practice due to stability problems. Improved strategies for distillation control offer a viable means for significant economic savings as compared to the existing ad hoc techniques. This thesis addresses robust control of distillation columns in the face of model-plant mismatch caused by model uncertainty, nonlinearity and changes in operating conditions. The robust control paradigm, introduced by Doyle and coworkers, is used as the basis for controller design and analysis. An important tool is the Structured Singular Value (SSV) which enables the evaluation of a plant's achievable control performance. This provides a consistent basis for comparing controllers and design alternatives. Achievable performance is also related to other commonly used measures such as the RGA and the condition number.

Covidien and VNUS Medical Technologies, Inc. announced that Covidien signed a definitive agreement to acquire VNUS, a company specializing in the development of medical devices for minimally invasive treatment of veins with venous reflux disease.

VNUS earned revenues of $ 101 million in 2008 and is headquartered in San Jose, California. The Boards of both companies unanimously approved the transaction under which a wholly owned subsidiary of Covidien will pay $ $ 29.00 in cash per share of VNUS, totaling approximately $ 440 million, net of cash acquired. It is estimated that the transaction is complete for the June 30, 2009, taking the form of a full bid in cash, followed by a second stage of the merger. It is subject to customary closing conditions, including receipt of certain regulatory approvals.

Covidien and VNUS Medical Technologies, Inc. announced that Covidien signed a definitive agreement to acquire VNUS, a company specializing in the development of medical devices for minimally invasive treatment of veins with venous reflux disease.

VNUS earned revenues of $ 101 million in 2008 and is headquartered in San Jose, California. The Boards of both companies unanimously approved the transaction under which a wholly owned subsidiary of Covidien will pay $ $ 29.00 in cash per share of VNUS, totaling approximately $ 440 million, net of cash acquired. It is estimated that the transaction is complete for the June 30, 2009, taking the form of a full bid in cash, followed by a second stage of the merger. It is subject to customary closing conditions, including receipt of certain regulatory approvals.

On behalf of the association's future European CO2 Technology Center Mongstad (TCM), StatoilHydro has signed a contract for engineering, procurement and construction (EPC) with Aker Clean Carbon AS for plant amine TCM. The contract is worth approximately 525 million Norwegian kroner.

According to plans, TCM must prove two different technologies for capturing CO2 from two sources of gas tubes with contents of low and elevated CO2. The contract with Aker Clean Carbon technology amines to last until the end of 2011. In addition, TCM is planned to test the processes of CO2 "ammonia-cold." The TCM project is working to build a successful an equivalent contract with another contractor.

On behalf of the association's future European CO2 Technology Center Mongstad (TCM), StatoilHydro has signed a contract for engineering, procurement and construction (EPC) with Aker Clean Carbon AS for plant amine TCM. The contract is worth approximately 525 million Norwegian kroner.

According to plans, TCM must prove two different technologies for capturing CO2 from two sources of gas tubes with contents of low and elevated CO2. The contract with Aker Clean Carbon technology amines to last until the end of 2011. In addition, TCM is planned to test the processes of CO2 "ammonia-cold." The TCM project is working to build a successful an equivalent contract with another contractor.