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What operational and design criteria need to be considered when specifying a glass-lined reactor?

This information is intended to help you establish the specifications that need to be defined in order to obtain a representative price quote.

Reactor Type and Size

There are a variety of different reactor types, each with their own set of unique features that make them advantageous for different utilization. Size is also an important factor. When you are determining what size reactor you need you’ll want to consider the minimum and maximum batch volume to help determine what size reactor will provide the best environment to optimize process performance. There is no “rule of thumb” that is applied to deciding the optimal batch volume, but generally customers use 70-80% of full capacity.

Vessel Lining

There are three options available for glass grade: 3009 blue, 3009 U white, and ConductiGlass. The first two options are simply what color glass is preferred based on the color of your product. Some companies opt for a dark glass while others find they get better visibility with white. ConductiGlass is a product that formulates the glass lining with platinum fibers to eliminate electrostatic charges that could potentially cause damage to the glass lining.

Design Code

The American Society of Mechanical Engineers (ASME) provides a standard boiler and pressure vessel code (BPVC) to ensure vessels are built in accordance with the rules they’ve established for safety and service life. The standard design code for glass-lined vessels is ASME Section VIII.

Design Conditions

All De Dietrich reactors are manufactured with a standard pressure and temperature range that applies to the inner vessel, jacket, and half coil pipes in the case of HemiCoil jacketed reactors. The normal pressure and temperature ranges are -1/+6 bar and -25/+200°C respectively. Designs are available that exceed these typical design conditions, so if you require greater allowances it should be made clear in this section.

Working Conditions

When fabricating a vessel, it is important for the manufacturer to be aware of the anticipated working conditions in order to ensure the design will be in adherence to usage. Please provide the working pressure and temperature as it relates to your specific process as well as additional specifications described below:

  • Inner vessel pressure and temperature
  • Jacket pressure and temperature (if applicable)
  • Half Coil pressure and temperature (if applicable)

In the case of a conventional jacket or HemiCoil reactor, a list of the intended heating/cooling medium will help to assess any possible zones or circuits that may need to be set up.

Areas and Zones

From a design perspective, it is necessary for an equipment manufacturer to know what area and zone you intend to install your reactor in so we are aware of any hazards that may be present such as flammable gas, vapors, and dust. For example, if your reactor is not installed in an explosion proof area, then upgrading to an XP model that features intrinsic safety enhancements may be required. All supplementary hazards that may be present should be noted, including gas, dust, and seismic zones. If you are geographically located in or near a seismic zone, a special design requirement will need to be taken into account when engineering and installing the vessel. By identifying the gas group and temperature class that applies to your equipment, we will be able to ensure your equipment will run per your specifications without any risk of explosion.


Exterior Design

While the fine points of what’s going on inside a reactor are the primary concern, the exterior finish and components are also crucial details when determining the cost of your reactor. The standard exterior finish used by DDPS are:

  • Primer - Sherwin Williams Zinc Clad IV organic Zinc-Rich Epoxy (Gray)
  • Finish - Sherwin Williams Acrolon 218 HS Acrylic Polyurethane (Gray)

If you prefer a different material for the external finish or a different color, simply tell us the MOC as well as the RAL number (RAL being a color matching system).

Nozzles and Manway Covers

The top head of each size and model reactor come with a standard design of nozzles (as a guide refer to our Resource Library). Prior to vessel fabrication, additional nozzles can be added to the design to help carry out process objectives. The manway cover on reactor models is available in a variety of arrangements, the standard being comprised of a dished cover with one sight glass. The following alternatives are also available – a flat cover with one fused sight glass and one quick easy opening, a flat cover with two fused sight glass. Opening assistance via davit or spring assist can be added to prevent possible glass damage from manway covers being accidentally dropped and slammed closed. A halogen or optic fiber lighting fixture can be installed onto your sight glass to assist with visual inspection of the contents in your reactor. As for the bottom of the vessel, the outlet nozzle is available in the standard design or with a pad flange.

HemiCoil Jacket Arrangement

If you’re opting for a HemiCoil jacket for your reactor, you have the advantage of creating multiple circuits and/or zones which will prevent cross contamination of heating and cooling mediums and increase versatility and efficiency in heat transfer. Optional arrangements include 1 circuit/1 zone, 1 circuit/2 zones, 1 circuit/3 zones, and 2 independent circuits.


Insulation options include sheathing on the shell and bottom head in stainless steel, foam glass, Rockwool, or other material. Different insulation materials have varying temperature limitations so if you are unsure of what kind you need, a DDPS representative can help make that decision for you. The standard thickness of insulation is two inches; however the thickness is ultimately a result of heat transfer requirements. An inspection port can also be added as an option. To assist with the adhesion of the insulation to the vessel, insulation rings should be used to help keep it banded. You can specify instructions for this or simply opt for the standard.


Support for your vessel comes in various forms including legs, lugs, support rings, and skirts. The type you choose will depend on your vessel size and installation specifications.


Baffle and Dip Pipe

There are a number of internal components of a reactor that require specification. If you aren’t in the market for an OptiMix reactor, then you will need to consider another baffle design. The two options are a beavertail baffle and a baffle combined with a dip pipe. A thermoprobe that enables reliable in-process temperature measurement is available in both models. If you select a dip pipe to be installed, you’ll have to decide on the length, material of construction (glass-lined, PTFE, or other) and we will confirm the design is feasible and adequate for the agitation forces (if agitated vessel).


The agitator blade you choose will depend on your process objective. Single or multiple-tiered agitators are available and you can select different types of blades for each stage of the process. Blade designs include traditional welded units (anchor, turbine, or impeller) or removable GlasLock blades (flat, trapezoidal, breaker bar, HydroFoil, OptiFoil, or ViscoFoil). For easy visual detection of liquid levels calibration lines can be added to the agitator shaft. Specially shaped agitators can also be designed to reduce space between the blades and the bottom of the agitator in the case of processes that require minimum agitated volumes.


To complement your agitator, a fixed speed or variable speed drive can be added to your mixing system. The motor and drive size will be determined based on your reactor model and size. All drives can perform clockwise or counterclockwise rotation of the agitator. Some processes benefit from peripherals like a revolution counter (electronic), tachometer (mechanical), or frequency converter which are offered along with your drive.

Mechanical Seal

Mechanical seals are a critical component of a mixing system. OptiSeal is the new standard design on all DDPS reactors that meets the stringent process requirements of today’s pharmaceutical and chemical manufacturing environments. This innovative seal design is comprised with stainless steel housing and helps users establish compliance with USP (U.S. Pharmacopeial Convention) and BPE (ASME Bioprocessing Equipment) guidelines. If you prefer, other double lubricated seals (John Crane or Flowserve brands in carbon steel or stainless steel housing), double dry (with or without nitrogen pressurization panel), or double gas/dry with no contact are also available. And after all of those options, if you can find another one that suits your needs better, just let us know! The sealing medium will also need to be determined for wet seals from the given options – fool grade oil, oil, or other. And for metered readings, instrumentation on the lubrication device is even available.

Bottom Outlet Valve

Our Clean Valve has become the new standard for glass-lined reactor flush valves and can be used across a wide temperature and pressure range. (Read more about it to learn about the cleanability features). The Clean Valve is offered with air operator, with hand wheel, flat seat, or standard seat. A thermoprobe SVR2 (2xPt 100 ohms) with lateral dismantling and junction box can also be included for accurate and reliable temperature measurement at the lowest point of the vessel (and measurements can be taken without have to interrupt the process or dismantle the valve).


Other Peripherals

Additional components for your reactor seem almost endless, but here is a list of just a few additional items for you to consider:

  • Sampling baffle BLE with or without pH measurement
  • TSU sampling system with or without pH measurement
  • Electrode Holder Probe GPE 100
  • Endress+Hauser level measurement
  • Endress+Hauser level switch
  • GlasWatch for continuous monitoring of the glass with electrodes (installed in valve, spacer probe or baffle)
  • Spray ball (PTFE, Hastelloy C-22, other Alloy)
  • Other glass-lined equipment