Supercritical CO2 extraction pilot plant design - towards IoT integration

Abstract

Preliminary communicationThe interest in high pressure technology during last decades increased intensively. Supercritical Fluid Extraction (SFE) is a process that is growing in importance as an alternative to conventional separation processes. SFE uses environmentally friendly CO2 as the extracting agent in the process because of its relatively low critical pressure (7,38 MPa), its low critical temperature (304 K), its non-dangerous character and low cost. During this process it is necessary to use high pressures in the procedure. The extractor vessel (pressure vessel) is the most important equipment of the system, where the supercritical conditions need to be established and the extraction occurs. Also other devices (separator vessel, heat exchangers, valves etc.) are necessary to be involved in the process due to used high pressures. Safety is the most important factor while dealing with SFE systems and the design of such equipment with full safety of process is very hard task. Therefore, to achieve the high desired safety level, a reliable control system must be designed as the control system and data communication segment. Various different process parameters such as CO2 mass flow rate, extraction pressures and temperatures affect the extraction process and the quality of the extract; hence these parameters need to be precisely controlled and monitored during the extraction. A design of one supercritical CO2 extraction laboratory-pilot plant and development of a remote control and its supervision system is presented in this paper. The developed SFE system (mechanical and electrical components) was compared with the existing commercial systems and its main advantages over the existing systems are presented. By enabling remote control and supervision the classical process control is joined with the concept of Internet of Things (IoT), where the information becomes omnipresent in the vast realm of Internet.Keywords: embedded system; process control; supercritical fluid extraction; system construction. Projektiranje pilot postrojenja za ekstrakciju superkritičnim CO2 -prema integraciji s Internetom objekata (IoT)Prethodno priopćenje Interes za tehnologije visokog tlaka tijekom posljednjih desetljeća se intenzivno povećava. Ekstrakcija super kritičnim fluidima (SFE) je process koji predstavlja alternative konvencionalnim postupcima separacije. U procesu ekstrakcije superkritičnim fluidima koristi se ekološki CO2 kao ekstrakcijsko otapalo zbog relativno niskog kritičnog tlaka (7,38 MPa), niske kritične temperature (304 K), poželjnih svojstava i niske cijene. Tijekom ovog postupka, potrebno je rabiti visoke tlakove. Ekstrakcijska posuda (posuda pod tlakom) je najvažnija oprema sustava, gdje se trebaju ostvariti kritični uvjeti i gdje se odvija ekstrakcija. Također, u procesu se treba obratiti pažnja i na druge dijelove uređaja (separator, izmjenjivače topline, ventile i sl.) zbog uporabe visokih tlakova. Sigurnost je najvažniji factor kada se radi o SFE sustavima i projektiranje takve opreme s potpunom sigurnosti ...

Identification of a Supercritical Fluid Extraction Process for Modelling the Energy Consumption

“…Even though the opportunities of energy efficient production, along with the disadvantage caused high energy demand of SFE operation are acknowledged [4,5], only few have touched upon the subject of energy analysis in SFE studies: Smith et al analyzed the energy efficiency of SFE by investigating energy losses through pump and compressor cycles [6]. Sievers optimized SFE by investigating the effects of CO 2 pressure, extractor temperature and separator pressure on energy costs and produced soybean oil [7].…”