Process Stability For Flawless Execution: From Pump Size To Reactor Material

Process stability – consistency of the process with respect to specific characteristics – is vital in order to achieve flawless execution of any reaction system. And this means leaving no parameter left unexamined.

First, determine the parameters of each application. Only then can you select the most suitable temperature control unit (TCU) and additional reaction solutions.

Know Your Pressure, Know Your Flow

Size your pump.
Let’s say you need to hard pipe into an application in another room. How do you decide on pump size?

• The two main parameters you need to consider are pressure (pounds per square inch, or PSI) and flow rate (gallons/liters per hour/minute) requirements.
• Feeding into these parameters is elevation. Maybe you need to pipe over a wall or up 10 feet, for example. This change in elevation, coupled with the total volume of hard piping needed, will determine pressure and flow rate requirements.

Choose your unit.
The integrated pump in your temperature control unit (TCU) must be powerful enough to achieve the required flow rates at constant pressure. If your application has a flow restriction, like narrow tubing, you’ll have to select a TCU with the pump sizes you need to meet those pressure and flow rate requirements.

Heed your specs.
Specifications established in the Pressure Equipment Directive 97/23/EG and by reactor manufacturers provide maximum pressure values for every type of reactor. The applicable limits must be programmed into the TCU before starting up an application.

Regulate your capacity.
The pump should provide the required pressure quickly and with maximum control to avoid exceeding pressure limit values. Regulation of pump capacity should be made in steps or by presetting a limit value.

• Knowing you have a larger-capacity chiller that has a manual control bypass allows you to ensure that tubing, piping and jacket pressures do not exceed their recommended limits.
• TCUs that control pressure with an internal pressure sensor are more effective than units with a pressure relief valve. Even though the pressure relief valve will ensure the reactor doesn’t break, it may leave you with a mess of recirculating fluid – potentially compromising nearby applications.

Explore your options.
Advanced TCUs feature pumps that automatically and dynamically balance changes in viscosity of the heat transfer liquid to ensure continuous maintenance of energy efficiency (since viscosity affects flow and, therefore, heat transfer). Magnetically coupled pumps provide an additional advantage as they ensure a hydraulically sealed thermal circuit. Self-lubricated pumps are also beneficial because they are virtually maintenance-free.

Know Your Materials, Know Your Design

Reactor material and design have a significant influence on the temperature control of highly dynamic reaction systems.

• PRESSURE: Glass reactors are sensitive to jacket pressure, and usually cannot exceed 8 PSI. Stainless steel or other metal-jacketed applications have higher pressure capabilities. This enables the TCU to operate at a high flow rate, which lowers the fluid turnover rate and increases thermal heat flow.
• FLOW: Flow restrictions affect time-to-temperature performance by increasing the bath fluid flow circuit pressure. For glass reactor applications, utilize the largest ID (inner diameter) fittings possible to reduce pressure and maximize flow rate.
• THERMAL STRESS: Glass reactors are more sensitive to thermal stress than steel reactors, and therefore have lower Delta-T limits.
  • The Delta-T limit is the maximum difference between the actual thermal fluid temperature and the temperature of the contents of the reactor.
  • Any temperature control unit should allow you to program reactor-specific values for the Delta-T limit per time unit.

Cheers to process stability and a successful experiment that checks all the boxes: cost effective, energy efficient, optimum functionality.

Like the TCU intel you’re getting from this blog? Well, there’s much more to come. But for some more personalized guidance, click the button below to consult with one of our Reaction Solutions Specialists. We’ll help you keep process stability in check for flawless execution of any temperature-controlled experiment.