Process intensification A Polymer Reactor Designed for Solvent-Free Operation
The Kneader Reactor from List offers a pathway to process intensification in both living- and free-radical polymerization. Process intensification is an approach to process and plant design that can minimize costs, increase flexibility and deliver higher yields.
A discussion of the reactor will be part of a presentation by List’s product manager Roland Kunkel at Achema. He will present “Energy-Efficient Processes in the Polymer Industry” on June 18, 2015 at 12:30 pm in the Achema Congress Center.
List has been a pioneer in the area of dry processing, and the company’s Kneader Reactor is an example. The reactor is designed operate in the concentrated phase, with little or no solvent, with a polymer concentration between 40 % and 99 %.
The Kneader Reactor provides constant surface renewal that improves heat transfer, according to List. It also allows excellent temperature control and minimizes the diffusion and mass-transfer limitations of conventional approaches, List adds. Conventional stirred-tank reactor technology for polymerization reactions has several shortcomings because of its requirement for solvents with concentrations up to 90 % in order to transfer heat and facilitate the mixing of the polymer solution during polymerization. In traditional chemical reactions, solvents are required to reduce viscosity and promote heat transfer. This is especially true when dealing with highly viscous, sticky materials.
With conventional technology, it is also difficult to reduce the level of solvent used because of the likelihood of developing hotspots and potential thermal breakdown. Once the polymerization is complete, solvents must be removed and treated, at significant energy cost and with possible safety and environmental impacts.
The Kneader Reactor overcomes these challenges in a way that allows process intensification, and its attendent benefits of elimination of process steps. An optimized process with the List Kneader Reactor saves raw materials, reduces energy consumption and increases process efficiency. In addition, the product quality is improved and Opex and Capex are lowered, the company says. Running the process in the concentrated phase also minimizes the environmental impact by eliminating solvents and toxic materials.