As a result of the heat-transfer capacity, highly exothermic reactions can be performed. This means that solvents can be reduced or reactions run at new conditions. With the higher operating temperatures and pressures, new possibilities for operating processes are facilitated.
Different zones can also be established along the reaction channel. This means that a chemical manufacturer can perform different reaction steps in a single unit, reducing both equipment needs and process set-up.
Cleaning and Inspection
In any hygienic process, the ability to clean and inspect is essential. The plate reactor can be disassembled and reassembled easily, facilitating thorough cleaning and reducing downtime. The flow through the unit is almost ideal plug flow and combined with good mixing, can reduce unwanted side reactions.
When using a batch reactor to perform a reduction reaction (Figure 2), a typical operating procedure includes many steps. These steps include filling the reactor with reactant and solvent and then cooling to 0°C, slowly adding excess of the reduction agent, RedAl, over 2–4 hrs while cooling to keep the temperature and the reaction rate low, and then more mixing and cooling. For the hydrolysis step, this procedure is largely repeated. Then, users filter off solid waste, perform product separation, and end up with a 80–90% yield of the purified product.
In a standard batch operation in a 1 m3 stirred-tank reactor, the reactions will take place over hours compared to the plate reactor, where the reaction takes place in seconds.
A plate reactor with three plates was used for comparison with a batch reactor. All of the plates are connected in series and operated at the same temperature; water was supplied as the utility fluid from a simple mixer tap.
RedAl solution was passed through the first plate to establish the reaction temperature. At the first port of the second plate, benzyl acetone was added, and the reaction was initiated. In the final plate, the hydrolysis solution was added. Pressure was adjusted to prevent too much vapor or boiling.
Using thermocouples placed in the remaining reactor ports (Figure 3), the progress of the reaction was viewed. In the second reactor plate, where the RedAl reaction took place, there was a temperature peak corresponding to the reaction heat. The peak was sharp and close to the feed point—indicating an almost instantaneous reaction.
Despite this, the yield was almost quantitative. During operation, the system was also able to handle the hydrogen gas evolved from the hydrolysis of excess RedAl.