Armfield – Chemical Engineering – CEXC Computer Controlled Chemical Reactors Training Equipment
The Armfield CEXC family is a range of chemical reactors specifically developed for the teaching and demonstration of chemical reactor capabilities to chemical engineering students. Real chemical reactions take place within the reactors, and Armfield have developed a number of representative reactions which are easy and safe for students to use in the laboratory environment. This range of small-scale chemical reactors comprises five units, which represent the types of reactors found in the industry. Three of the reactors mount on a common bench top service unit (CEXC) whilst the other two are free-standing. PC based educational software is included along with the necessary interface device to provide computer control, automatic logging of data and analysis of results. Reactors comprise: Plug Flow, Laminar Flow, Stirred Tank, Tubular and Batch reactors.
The CEXC Chemical Reactors Teaching Unit provides the services required to run the various reactor types. It includes a hot water re-circulator used to control the temperature of the reactions, glass feed vessels for the reactants, two peristaltic pumps to pump the reagents to the reactors, computer software for data logging, sensors and instrumentation.
The CEXC is fully computer controlled, and supplied with software to allow the user to vary the feed pump speeds and flow rates, to vary the heater power in the hot water, to implement a PID control loop ensuring stable temperatures, switch on and off the hot water pump, and to control the speed of the stirrers used on some of the reactors.
Instrumentation for temperature and conductivity measurements is also supplied and these values are displayed on the computer screen. Two ‘K’ type thermocouples are included, one for the hot water and one for the reactor contents.
Note: An input for a third user supplied sensor is also provided for project work.
A dual-range conductivity sensor allows for a wide range of operation. Armfield have developed an algorithm for the saponification reaction (ethyl acetate and sodium hydroxide) linking the degree of conversion of the reactants to the electrical conductivity, thus allowing the progress of the reaction to be monitored using the software.
The service unit includes a mounting position for the reactor being used. It is possible to change reactors quickly and easily without the use of tools. All fittings on the CEXC and the reactors are of the quick-release type. The CEM-MkII, CET-MkII and CEB-MkIII reactors are completely contained on the CEXC base unit. The CEY and CEZ also include floor standing columns for positioning next to the CEXC base unit.
The CEXC provides a locating position for two standard 2.5-litre chemical storage bottles for the reagents within the plinth. This provides safety in use, and the bottles can be quickly capped and removed as necessary for safe handling. Two 2.5-litre bottles are also provided with the equipment. Alternatively, for longer experiments, larger feed vessels could be located either on the floor or on the bench next to the equipment.
The CEXC requires a computer (not supplied by Armfield), running Windows XP or above, with a spare USB port.
Available Models
The CEB Transparent Batch Reactor is a double-skinned glass vessel with a one-litre internal working volume, fitted with a variable-speed agitator.
Hot water from the CEXC or cold water from the CW17 can be circulated through the jacket for temperature control purposes, maintaining the reactor contents at constant temperature.
Glands in the clear acrylic lid allow the CEXC conductivity and temperature probes to be fitted to facilitate monitoring of the reactions in progress such as the important saponification reaction. Isothermal and adiabatic operation reactions may be demonstrated. (Note, the isothermal reaction requires the Armfield CW17 accessory if experiments at low temperature are to be studied or if the ambient temperature is high).
For adiabatic operation, the use of dyes enables the chemical reaction rates to be monitored visually by the change in colour at different degrees of conversion.
Key Features
- A small-scale batch reactor for use with the Chemical Reactors Service Unit designed to demonstrate both adiabatic and isothermal operation (The Chilled Water Circulation Unit accessory is recommended for isothermal operation)
- 1l working volume
- The vessel includes a jacket through which hot water from the Chemical Reactors Service Unit or chilled water from Chilled Water Circulation Unit is passed. A variable-speed agitator aids heat transfer through the vessel
- The vessel is made of glass to give full visibility of the contents and allow the use of colour tracers to illustrate the reaction process
- Fitting points for temperature and conductivity sensors (supplied with Chemical Reactors Service Unit)
- Demonstration capabilities:
- Effect of temperature on reaction kinetics
- Effect of concentration on conversion
- Determination of the rate equation and activation energy through mass and energy balances
- Study of temperature variation for exothermic reaction
- Use of colour tracers to illustrate reaction progress
The continuous stirred tank reactor is probably the most common type of reactor found in industry. The Armfield CEM-MkII is a small-scale demonstration version for educational use. It is extremely flexible in use and can be used for both continuous and batch reactions.
The volume of the reactor is adjustable between 0.4 and 1.5 litres using an adjustable standpipe, allowing different hold-up volumes and residence times to be investigated. The temperature probe and conductivity probe (supplied with the CEXC) can be positioned in the reactor vessel.
A stainless steel coil is used for temperature control of the reactor from the hot water supply on the CEXC (or cold water from such as the Armfield CW17 Chilled Water Circulating Unit).
A variable-speed mixer/agitator is included (controlled by the CEXC) together with baffles to improve the mixing.
CEM-MkII uses the saponification reaction and uses conductivity to measure the progress of the reaction. It also uses a step input change experiment to obtain the residence time distribution.
Key Features
- A small-scale continuous stirred tank reactor for use with the Chemical Reactors Service Unit
- Adjustable volume of 0.4-1.5l
- The vessel is equipped with a variable-speed square blade turbine agitator
- The vessel is constructed from borosilicate glass and PVC, with stainless steel heat transfer coil and removable reactor baffle
- Fitting points for temperature and conductivity sensors (supplied with Chemical Reactors Service Unit)
- Demonstration capabilities:
- Effect of residence time on conversion
- Determination of reaction rate constant
- Residence time distribution
- Evaluation of empirical rate expressions from experimental data
- Effect of temperature on reaction rate
- Effect of mixing on reaction rate
- Effect of flow rates on conversion
The Armfield Tubular Reactor is in the form of a tube wrapped in a spiral around an acrylic former, which is enclosed in a transparent tank. Water at a controlled temperature (from the CEXC) is circulated within the tank, this maintains the reactants at constant temperatures.
The reagents are piped separately to the reactor through quick-release fittings mounted on the lid and are preheated in stainless steel coils in the water tank, before being mixed and fed into the reactor coil.
Mounting positions are provided for the CEXC water temperature sensor (in the water tank) and the conductivity probe (at the reactor output).
CET-MkII uses the saponification reaction and uses conductivity to measure the progress of the reaction.
Key Features
- A small-scale tubular reactor for use with the Chemical Reactors Service Unit capable of demonstrating large-scale behaviour
- The 20m long reactor coil is mounted in a clear acrylic vessel through which heating or cooling medium is circulated. Volume of reactor coil is 0.4l
- Two heat exchanger coils bring the reactants up to the reaction temperature separately before they are mixed to start the reaction
- Fitting points for temperature and conductivity sensors (supplied with Chemical Reactors Service Unit)
- Demonstration capabilities:
- Determination of reaction rate constant
- Investigation of the effect of throughput and flow rates on conversion
- Demonstration of the temperature dependence of the reaction and the rate constant
- Determination of the residence time distribution
The CEY Plug Flow Reactor demonstrates step and pulse changes for plug flow characterisation and steady-state conversion for a second order reaction. It is a tubular packed column reactor made of clear acrylic and mounted on a steel frame. A static premixer at the bottom of the column provides premixing of the reagents entering the reactor and improves the flow distribution.
A clear acrylic sensor block is mounted on the floor standing frame and houses the CEXC conductivity and temperature sensors. The reagents are fed to the reactor by the CEXC feed pumps, using PTFE tubing. A six-port injection valve fitted to the CEXC Reactor Service Unit is used to provide the step or pulse input changes of the reagents.
Tracer experiments and conversion experiments may be demonstrated and followed visually. Conductivity data logging allows the student to apply the flow pattern characterisation theory and compare it with the experimental results.
Key Features
- A small-scale plug flow reactor for use with the Chemical Reactors Service Unit, designed to demonstrate both flow pattern characterisation and steady-state conversion in a packed tubular reactor with axial dispersion
- The reactor column is 1,044mm long, with a 1l working volume. It is packed with 3mm diameter glass beads
- A feed assembly is supplied with the reactor which consists of a six-port injection valve mounted on a base plate and a feed vessel assembly with heat exchangers for cooling for use with the Chemical Reactors Service Unit and Chilled Water Circulation Unit
- The reactor assembly is mounted on a painted frame and includes a sensor block for the conductivity and temperature sensors from the Chemical Reactors Service Unit
- Can perform flow visualization where the progress of the reaction can be monitored visually using colour
- Can also perform true reactions where the progress of the reaction is recorded using the Service Unit conductivity sensor and compared with the theory
- Demonstration capabilities include:
- Flow pattern characterisation in a packed Plug Flow reactor with axial dispersion
- Steady-state conversion for a chemical reaction in a packed reactor
- Understanding the principles of tracer techniques in flow pattern characterisation
- Visual monitoring of the tracer and conversion experiments using colour
The Armfield Laminar Flow Reactor is a tubular reactor made of clear acrylic and mounted on a floor standing steel frame, with two diffusers packed with glass beads located at the ends. A static premixer at the bottom of the column provides premixing of the reagents entering the reactor and improves the flow distribution.
It includes two reagent vessels fitted with heat exchangers, mounted in the CEXC plinth. The heat exchangers are used to cool down the reagents before performing the experiment. A cold water jacket keeps the reactor contents at constant temperature in order to maintain the laminar characteristic. A thermostatically controlled supply of chilled water is required for this, such as the Armfield CW17.
A clear acrylic sensor block is mounted on the frame for the CEXC conductivity and temperature sensors. The reagents are fed to the reactor by the CEXC peristaltic pumps, using PTFE tubing. Pulsation dampers are used to ensure a smooth flow.
Tracer experiments and conversion experiments may be demonstrated and followed visually. Conductivity data logging allows the student to apply the flow pattern characterisation theory and compare it with the experimental results.
Key Features
- A small-scale laminar flow reactor (400ml working volume) designed to demonstrate both flow pattern characterisation and steady-state conversion in a tubular reactor
- The reactor column is 1300mm long including diffusers packed with glass beads
- A static premixer is fitted at the base of the column
- Reactor column is jacketed with easy connections for rercirculating cooling system
- A feed assembly is supplied with the reactor which consists of two pulsation dampers mounted on a base plate, special lids for Service Unit reagent vessels and PTFE interconnecting pipe
- Stainless steel coils are mounted on the reagent vessel lids to cool their contents. Quick-release connectors allow easy supply of cold transfer medium to the coil and reagents
- The unit is mounted on a painted frame and includes a sensor block for conductivity and temperature sensors
- Can perform flow visualization where the progress of the reaction can be monitored visually using colour
- Can also perform true reactions where the progress of the reaction is recorded using the Service Unit conductivity sensor and compared with the theory
- Requires a Service Unit
- Demonstration capabilities include:
- Flow pattern characterisation in a laminar flow reactor
- Steady-state conversion for a chemical reaction with laminar flow
- Understanding the principles of tracer techniques in flow pattern characterisation
- Visual monitoring of the tracer and conversion experiments using colour
Key Features
CEXC Computer Controlled Chemical Reactors Training Equipment
- A self-contained benchtop service unit designed to provide services for up to five different chemical reactors:
- Continuous Stirred Tank Reactor
- Tubular Reactor
- Transparent Batch Reactor
- Plug flow reactor
- Laminar Flow reactor
- Fully computer controlled and supplied with educational software specific to each reactor type. Simple interfacing to the (user-supplied) computer by a USB interface
- Two peristaltic feed pumps with individually variable flow rates, 0-140 ml/min
- Provides PID temperature controlled hot water in order to maintain reactor temperature
- Complete with two thermocouples, an input for a third (user) thermocouple and a dual range conductivity sensor
- A comprehensive instruction manual is included, which details installation and operating procedures
Key Industries
- Biopharmaceutical and Biotechnology
- Chemical
- Cosmetics & Personal Care
- Education & Academics
- Food & Beverage
- Oil & Gas
- Pharmaceutical
- Powders & Pigments / Coating
Brand
The Armfield Industrial Division designs and manufactures research & development systems, primarily for the food, beverage, dairy, edible oil and pharmaceutical industries. Used by many of the world’s leading corporations, Armfield systems enable researchers and product developers to replicate full-scale industrial manufacturing processes on a miniature-scale in the laboratory.
