Assessment of the Possibility to Remotely Monitor and control a pH process: An experimental study

The control of pH is important in many processes including wastewater treatment, chemical processes and biological processes. This paper considers a model reference non-linear controller developed by Jayadeva et al. (1990a). The method is tested using a 7-litre continuously stirred tank reactor to neutralise a strong acid using a strong alkaline solution. The method is first realised using a simulation of the process. Subsequently it is demonstrated on an experimental rig using real-time control. Experimental results confirm that a robust control of the process is achievable

The effect of melt viscosity on thermal efficiency for single screw extrusion of HDPE

YesIn this work, a highly instrumented single screw extruder has been used to study the effect of polymer rheology on the thermal efficiency of the extrusion process. Three different molecular weight grades of high density polyethylene (HDPE) were extruded at a range of conditions. Three geometries of extruder screws were used at several set temperatures and screw rotation speeds. The extruder was equipped with real-time quantification of energy consumption; thermal dynamics of the process were examined using thermocouple grid sensors at the entrance to the die. Results showed that polymer rheology had a significant effect on process energy consumption and thermal homogeneity of the melt. Highest specific energy consumption and poorest homogeneity was observed for the highest viscosity grade of HDPE. Extruder screw geometry, set extrusion temperature and screw rotation speed were also found to have a direct effect on energy consumption and melt consistency. In particular, specific energy consumption was lower using a barrier flighted screw compared to single flighted screws at the same set conditions. These results highlight the complex nature of extrusion thermal dynamics and provide evidence that rheological properties of the polymer can significantly influence the thermal efficiency of the process. (C) 2014 The Authors. Published by Elsevier B.V. All rights reserved

Energy consumption analysis for a single screw extruder

Polymer extrusion is regarded as an energy intensive production process, the real-time monitoring of both thermal energy and motor drive energy consumption becomes necessary for the development of energy efficient management system. The use of power meter is a simple and easy way to achieve this, however the cost sometimes can be high. Mathematical models based on the process settings provide an affordable alternative, but the resultant models cannot be easily extended to other extruders with different geometry. In this paper, simple and accurate energy real-time monitoring methods are developed for the analysis of energy consumption of the thermal heating and motor drive respectively. This is achieved by looking inside the controller, and use the control variables to calculate the power consumption. The developed methods are then adopted to study the effects of operating settings on the energy efficiency. These include the barrel heating temperature, water cooling temperature, and screw speed. The experimental results on Killion KTS-100 extruder show that the barrel heating temperature has a negative effect on energy efficiency, while the water cooling setting affects the energy efficiency positively but insignificantly. Undoubtedly, screw speed has the most significant effect on energy efficiency.</p

Energy consumption analysis for a single screw extruder

Polymer extrusion is regarded as an energy intensive production process, the real-time monitoring of both thermal energy and motor drive energy consumption becomes necessary for the development of energy efficient management system. The use of power meter is a simple and easy way to achieve this, however the cost sometimes can be high. Mathematical models based on the process settings provide an affordable alternative, but the resultant models cannot be easily extended to other extruders with different geometry. In this paper, simple and accurate energy real-time monitoring methods are developed for the analysis of energy consumption of the thermal heating and motor drive respectively. This is achieved by looking inside the controller, and use the control variables to calculate the power consumption. The developed methods are then adopted to study the effects of operating settings on the energy efficiency. These include the barrel heating temperature, water cooling temperature, and screw speed. The experimental results on Killion KTS-100 extruder show that the barrel heating temperature has a negative effect on energy efficiency, while the water cooling setting affects the energy efficiency positively but insignificantly. Undoubtedly, screw speed has the most significant effect on energy efficiency.</p

Thermal optimisation of polymer extrusion using in-process monitoring techniques

NoPolymer extrusion is an energy intensive process, which is often run at less than optimal conditions. The extrusion process consists of gradual melting of solid polymer by thermal conduction and viscous shearing between a rotating screw and a barrel; as such it is highly dependent upon the frictional, thermal and rheological properties of the polymer. Extruder screw geometry and extrusion variables should ideally be tailored to suit the properties of individual polymers, but in practice this is rarely achieved due to the lack of understanding of the process. Here, in-process monitoring techniques have been used to characterise the thermal dynamics of the extrusion process. Novel thermocouple grid sensors have been used to measure melt temperature fields within flowing polymer melts at the entrance to an extruder die in conjunction with infra-red thermometers and real-time quantification of energy consumption. A commercial grade of polyethylene has been examined using three extruder screw geometries at different extrusion operating conditions to understand the process efficiency. Extruder screw geometry, screw rotation speed and set temperature were found to have a significant effect on the thermal homogeneity of the melt and process energy consumed. (C) 2012 Elsevier Ltd. All rights reserved