Sensors for Cryogenic Isotope-Separation Column

Cryogenic isotope-separation equipment is special, encountered in relative few research centers in the world. In addition to the main equipment used in the operation column, a broad range of measuring devices and actuators are involved in the technological process. The proper sensors and transducers exhibit special features; therefore, common, industrial versions cannot be used. Three types of original sensors with electronic adapters are presented in the present study: a sensor for the liquid carbon monoxide level in the boiler, a sensor for the liquid nitrogen level in the condenser and a sensor for the electrical power dissipated in the boiler. The integration of these sensors in the pilot equipment is needed for comprehensive system monitoring and control. The sensors were tested on the experimental equipment from the National Institute for Research and Development of Isotopic and Molecular Technologies from Cluj-Napoca

Control of a train of high purity distillation columns for efficient production of 13C isotopes

It is well-known that high-purity distillation columns are difficult to control due to their ill-conditioned and strongly nonlinear behaviour. The fact that these processes are operated over a wide range of feed compositions and flow rates makes the control design even more challenging. This paper proposes the most suitable control strategies applicable to a series of cascaded distillation column processes. The conditions for control and input-output relations are discusssed in view of the global control strategy. The increase in complexity with increased number of series cascaded distillation column processes is tackled. Uncertainty in the model parameters is discussed with respect to the dynamics of the global train distillation process. The main outcome of this work is insight into the possible control methodologies for this particular class of distillation processes

A one-step procedure for frequency response estimation based on a switch-mode transfer function analyser

Frequency response analysis is a well established system identification method. In this paper, a simple and efficient method based on the classical Transfer Function Analyzer (TFA) technique is implemented for system identification. The novel algorithm has been called Switch-Mode-TFA. The originality of the proposed approach consists of: i) using a chirp TFA test input instead of a pure sine function, ii) using a variable sampling period instead of the traditional fixed sampling period and iii) a simplified implementation using switched electric circuits. The advantage of our approach is thus threefold: i) the frequency response of the system is obtained for the entire range of frequencies by means of only one identification test; ii) the number of samples per cycle remains constant, independent of the excited frequencies and iii) it can be easily implemented in hardware platforms. The results in both simulation and real-life examples indicate that the proposed Switch-Mode-TFA method can be reliably used for frequency response analysis in many other applications