Process Reactors Information
Process reactors are used for commercial production applications in the range of 1,000 to 1,000,000 liters. They are sometimes called industrial-scale reactors. Process reactors are categorized as batch, continuous, or fed-batch, depending upon the way in which they process samples, products, and waste. Continuous process reactors can be many more times productive than batch reactors, and can be operated for long periods of time without being shut-down. Fed-batch reactors are more common, however, and can achieve high productivities.
Process reactor components. Image credit: Raymer Engineering
Batch process reactors are the simplest type. The process reactor is filled with medium and the reaction is allowed to proceed. When the reaction has finished, the contents are emptied for downstream processing. The reactor is then cleaned, re-filled, and re-inoculated so that the reaction process can start again.
Continuous process reactors are the most complex type. Fresh media is continuously added and reactor fluid is continuously removed. Cellular growth rate can be optimized by controlling the flow rate of the feed entering the reactor. Types of Continuous Process reactors are Continuous Stirred Tank Reactor (CSTR), Plug Flow Reactor, Tubular Flow Reactor.
CSTR: a vessel to which reactants are added and products removed while the contents within the vessel are vigorously stirred using internal agitation or by internally (or externally) recycling the contents. At steady state, the flow rate in must be equal the mass flow rate out. Fermentators are CSTR's used in biological processes such as brewing, antibiotics, and waste treatment.
Plug Flow Reactors, also called tubular reactors, consist of a hollow pipe or tube through which reactants flow. Water at a controlled temperature is circulated through the tank to maintain constant reactant temperature. Has a higher efficiency than CSTR. Applications can be in either gas or liquid phase systems. Common industrial uses are in gasoline production, oil cracking, synthesis of ammonia from its elements, and oxidation of sulfur dioxide to sulfur trioxide.
Tubular Flow Reactors consist of a tube or pipe through which reactants flow and are converted to product. They may have varying diameters along the flow path. Several tubular reactors in series or in parallel may also be used. Both horizontal and vertical orientations are common. Chemical reactions take place in a stream of gas that carries reactants from the inlet to the outlet.
Fed-batch process reactors are the most common type. Fresh media is continuously, or sometimes periodically, added to the bioreactor. Unlike a continuous process reactor, however, product and waste are not removed continuously.
Chemical process reactor. Video credit: Jihoon Bak/YouTube
Specifications and Features
Process reactors can control specific parameters such as dissolved oxygen, foam, pH, speed, and temperature. Vessel volume, temperature range, and pressure range are also important specifications to consider. In addition to processing capabilities, process reactors may have specialized features to maintain or eliminate specific conditions that could tamper with the resultant product. For example, some devices are designed for cleanroom environments. Others are jacketed, lined or coated, or equipped with an inspection or access port.
Process reactors are used in these industries.
- Adhesives processing
- Chemical processing
- Food and beverage production
- Paints and coating production
- Paper and pulp processing
- Pharmaceutical and medical production
- Plastics and thermoplastics processing