PROCES OCESS S PL AN T T RAI N E R
Submitted by: Shahbano Hashmi Bushra Ameer Alvia Asif Natashah Ashraf Hira Ehsan Aqsa Aslam
2013-PE-07 2013-PE-08 2013-PE-14 2013-PE-15 2013-PE-26 2013-PE-27
Submitted to: Mam Zoobia
Polymer department department Instrumentation and control lab
Contents Process Plant Trainer ...................................................................................................................... 2 Working principle ........................................................................................................................... 2 Features ........................................................................................................................................... 3 Instrumentation ............................................................................................................................... 3 3/2 way solenoid valve ............................................................................................................... 4 Peristaltic pump ......................................................................................................................... 4 Plate heat exchanger ................................................................................................................. 4
Control objective ............................................... .............................................................................. 4 Control (Manipulated Variables) .................................................................................................... 4 Possible loops.................................................................................................................................. 5 Level Control loop: ..................................................................................................................... 5 Product-Diverted valve loop: ...................................................................................................... 5 References ................................................ ....................................................................................... 6
Process Plant Trainer The PCT23-A is a bench top process control system, comprising a process unit mounted on an ABS plinth, an electrical control console, and cont rol software, which can be run on any Windows PC with a spare USB port. Diverted product
Plate type heat
Holding tube
Exchanger
Heated vessel
Feed tanks
Valves
Peristaltic pump
Process Unit: Figure 1. Process plant trainer
Working principle The process is modelled on an industrial high-temperature/short-time (HTST) pasteurization process. In this process the product stream has to be kept at a predetermined temperature for a minimum time, usually for bacteriological purposes. This is effected by the use of a holding tube, which delays the product stream, thus posing particular process control problems and introducing the concept of ‘dead time’.
Solenoid-driven valves control the filling and emptying of the se tanks. These enable different level control strategies to be developed and provide startup and shutdown operational sequencing capability. [1]
Features
Multiple inputs, multiple sensors, multiple control strategies. Manual control, single feedback loops, through to sophisticated cascade loops Temperature, level, flow control loops can be implemented Effects of ‘dead time’ Operational sequencing, including startup and shutdown Recycle implications on process control.
Instrumentation
2 way solenoid valve 3 way solenoid valve Peristaltic pump Plate heat exchanger Flow sensor Temperature sensor Level sensor
Figure 2. Schematic of process plant trainer
3/2 way solenoid valve A 3/2 way solenoid valve has three ports and two switching states. In each switching state, two of the three ports are connected. By activating the solenoid, the valve switches state and a different connection between the valve ports is established. In the de -energized state, the medium can flow between from the port on the right side to the top port. In the energized state, the medium can flow from the left port to the right port. This is a c alled a normally closed 3/2-way valve. [2]
Peristaltic pump The peristaltic pump is based on alternating compression and relaxation of the hose or tube drawing the contents into the hose or tube, operating in a similar way to our throat and intestines. A rotating shoe or roller passes along the length of the hose or tube totally compressing it and creating a seal between suction & discharge side of the pump, eliminating product slip. Upon restitution of the hose or tube a strong vacuum is formed drawing product into the pump. [3]
Plate heat exchanger The plate type heat exchanger is the most efficient type of heat exchanger with its low cost, flexibility, easy maintenance, and high thermal transfer. WCR plate corrugations are designed to achieve turbulence across the entire heat transfer area. This produces the highest possible heat transfer coefficients with the lowest possible pressure drop, allowing for close temperature approaches. Subsequently, this leads to a smaller heat transfer area, smaller units and in some cases, fewer heat exchangers. [4]
Control objective The product stream must be kept at a predetermined temperature for a minimum time.
Control (Manipulated Variables)
Product feed pump speed Heating fluid pump speed Heater power Temperature, flow, level measurement
Possible loops Level Control loop:
Product-Diverted valve loop:
References 1. http://discoverarmfield.com/en/products/view/pct23/process-plant-trainer-processcontrol-trainer 2. https://tameson.com/solenoid-valve-types.html 3. http://www.verderflex.com/en/how-do-peristaltic-pumps-work/ 4. http://www.wcrhx.com/plate-heat-exchangers
