Eternal placed an order with RHE H¿el Engineering GmbH, specialists in the design and supply of resin manufacturing plants. Eternal learned of RHE through their sister company in Thailand and was impressed by the efficient operations, innovative design, and high profitability of the Thailand project. In comparison, the existing resin manufacturing plants operated by Eternal in Taiwan, all supplied by local engineering houses, experienced operational and profitability problems. These problems included long batch times and high raw material consumption rates. Eternal placed an order with RHE for two resin manufacturing trains: one for the manufacture of alkyd resins and one for the manufacture of both alkyd and saturated polyesters resins.
RHE developed a turnkey operation including the complete basic and detailed engineering packages and key equipment such as reactors, pressure vessels, and agitators. The alkyd resin train included a 12,000 gal reactor. The alkyd and saturated polyester resin train included a 6,750 gal reactor. Eternal purchased some pieces of equipment locally based on RHE workshop drawings and specifications.
For the execution of this project, RHE drew on its over 40 years of experience both in the design of resin manufacturing plants and a specialized knowledge of reaction processes. To provide all the engineering and design work, RHE required a minimal amount of information about the raw materials from Eternal.
RHE designed the production trains with the following technical features.
Charging of Liquid Raw Materials -- Reactors and dilution tanks are installed on load cells so that liquids from storage tanks are charged accurately by weight through special charge valves.
Charging of Solid Raw Materials -- Solids from bags are charged through dust-free systems into hoppers installed on load cells. Screw feeders, with variable speed drives, pass the solids into the reactors.
Heating and Cooling of Reactors -- The reactors are heated and cooled by thermal oil, which is circulated through half-pipe coils on the exterior of the reactors. These secondary circuits include pumps, heat exchangers and automatic control valves.
Reaction Equipment -- The reactors are equipped with free-flying disk type pitched blade turbine agitators, custom designed to provide the most efficient mixing for every application. The reactors are also equipped with efficient distillation systems, which include a packed column, an automatic decanter and a reflux pump.
Plant Control -- Both trains are designed for an almost fully automatic operation through PC/DCS systems with recipe management.
Online Viscosity and Acid Number Measurement -- The reaction product viscosity and acid number are continuously monitored by the patented RHE-developed online circuit that is included with each reactor. This allows the resin manufacturer to preset target values for the final product.
The efficient design and execution of the plant equipment resulted in considerable batch time reductions in comparison to the existing plants. For the manufacture of alkyd resins, a two-step process starting from vegetable oils, batch times of between 16 and 18 hours are standard using the RHE-supplied equipment.
Use of the computerized process control system and the online measurement system for determining product viscosity and acid number have largely eliminated the manufacture of off-spec batches and greatly reduced the staff needed. Additionally, the product quality has improved since it is possible to manufacture resins with very narrow specification ranges.
The profitability of the alkyd and polyester resin manufactured on the RHE trains exceeded customer expectations. During the economic downturn starting in 1997 that resulted in the loss of Eternal's main export market, Japan, only the RHE resin plants remained in operation, while the less productive trains were, at least temporarily, shut down. c
For more information, contact RHE America, phone 630-577-0400 x212; visit www.rhe-america.com; or Circle Number 146.