Chemical company builds state-of-the-art emulsion plant.

Expanding their manufacturing to the U.S., Alberdingk Boley GmbH considered many factors in building a new facility. Headquartered in Krefeld-Uerdingen, Germany, Alberdingk manufactures polyurethane and acrylate emulsions used in producing high quality adhesives and coatings. In 2000 the company decided to expand their manufacturing operations to the U.S. and in 2002 selected a plant site in Greensboro, NC. Both polymer and polyurethane emulsions will be produced at the North Carolina site.

Alberdingk selected RHE Handel Engineering GmbH & Co. KG and RHE America to design and supply the equipment. Several factors were given special priority in designing the plant: safety, product quality, batch times, and turnaround time.

Safety

Volatile Monomer Storage -- Controlling the storage temperature of many of the liquid monomers is a critical safety issue. Alberdingk's storage tanks will include equipment to monitor the liquid monomer temperatures. Also included is an external heat exchanger loop that is cooled with chilled water. Any increase in the liquid monomer temperature will trigger automatic circulation of the monomer through the heat exchanger loop.

Monomer Blending -- Preventing runaway reactions within the monomer blending tank is another critical safety issue. RHE's system controls the temperature inside the monomer blending tank by continuously circulating cooling water through half coils located on the outside of the vessel. If the temperature inside the monomer-blending tank increases above the predetermined critical point, reaction inhibitor is automatically injected.

Reaction Start Point -- A continuous, online enthalpy measurement and temperature gradient system was included to determine the exact polymerization reaction starting point. If the reaction does not start at the expected time, the reactor is automatically shut down. Automatic shutdown includes: raw material feeding and reactor heating is stopped, reactor cooling is started, and alarms are triggered. After shutdown, the operator can sample the mixture in the reactor and decide on the correct course of action.

Product Quality

Raw Material Addition -- Consistent product quality starts with consistent addition of raw material. All tanks of the train are mounted on scales and the raw materials are added automatically by weight to assure consistent reproducibility.

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Full Automatic Process Control -- Fully automatic process control schemes, which included recipe management programs for the automatic processing of different types of formulations, and reports outlining all events for each batch were provided.

Short Batch Times

Agitation -- A custom designed agitator with avariable-speed drive to stir the reactor contents was included. This agitator provides both efficient horizontal and vertical mixing.

Heating/Cooling Circuit -- A controlled heating and cooling circuit was designed to maintain the preset temperature with an accuracy of [+ or -]1[degrees]C.

Minimize Turnaround Time

Reactor Cleaning -- In the production of polymer emulsions, the turnaround time between batches is used to clean the reactor. Polymer emulsions tend to stick, particularly to the inside of the reactor and the reactor agitator. RHE polished all surfaces in contact with the product to a mirror finish, including the reactor internals and the agitator surfaces.

Reactor Design -- During the production of polymer emulsions, monomer vapors without inhibitor rise to the top of the reactor vessels. A typical reactor is insulated at the top. As the monomer vapors rise, they tend to polymerize and form a layer of polymer, which hangs down from the top of the reactor vessel. The design for Alberdingk significantly reduces this problem. Rather than insulating the top of the vessel, this system was designed to cool it with water circulating through half pipe coils attached to the exterior of the reactor top. Therefore, the monomers rise to the top of the reactor, condense on the cool reactor surface, and flow back down into the reactants. This virtually eliminates the formation of a polymer layer on the interior of the reactor top.