Rineco pioneers automation of regulated liquid waste handling with Emerson's PlantWeb
Rineco Chemical Industries (www.rineco.com) has become the nation's first commercial waste treatment, storage, and disposal (TSD) facility to automate all its handling of regulated liquid waste. The key to Rineco's success is the latest generation of automatic controls using open PlantWeb? field-based architecture from Emerson Process Management. Results include lower installed and operating costs, greater throughput, and improved relations with customers and regulators.
Rineco handles a wide range of regulated liquid and solid wastes including solvents, paints, reacted epoxy resins, rags, plastic sheeting, and rubber boots. PlantWeb architecture was applied in a mainstay of the business, a process in which various solids and semi-solids are dispersed in spent solvents and similar liquids. The resulting combustible slurry is pumped into cement kilns as a supplement to conventional coal and natural gas fuel.
"We wanted automation that could be tailor-made to fit what this process involves," said Plant Manager Brad Cummock. "That's where PlantWeb architecture works so well. What makes Rineco unique in this industry is that we have fine-tuned our blending of solids into liquids, and our customer service, to a greater degree than some of our competitors, and the PlantWeb approach has become a major part of that advantage."
Efficient automation of such a process requires a complex piping network that simultaneously carries several different wastes on complex paths among numerous storage tanks and processing units. Securing the all-important operating permit requires proving that the control system always prevents overflows and unauthorized mixing while providing an auditable trail of everything coming in and out. Because of the difficulty of compliance using conventional automation, transfers have been controlled instead by "snake pits" of manually coupled hoses-until Rineco applied PlantWeb architecture.
"This was the first time I have ever seen a permit engineer with a smile on his face when he saw a new bulk liquid handling system," said R&D Vice President John Whitney. "From a permitting standpoint, this level of diligence just doesn't exist anyplace else in the chemical processing industry."
The reason PlantWeb architecture is called "field-based" is that in its full realization, automation is based primarily on intelligent field instruments. There is virtually no end to the amount of processing that can be pushed out to microprocessor-based transmitters and valve controllers networking together on field buses. Rineco's PlantWeb implementation uses FOUNDATION? fieldbus and HART? for communication with intelligent instruments, AS-i (Actuator Sensor interface) bus for discrete-signal instruments, and a DeltaV? automation system linked to operator and engineering stations by an Ethernet LAN.
The intelligent instruments using FOUNDATION fieldbus consist of 24 Rosemount pressure and temperature transmitters and five Micro-Motion mass flowmeters. In addition, there are eight intelligent radar level transmitters on the storage tanks that can communicate via HART protocol.
"Using the DeltaV system with fieldbus instruments," John Whitney explained, "we don't have any question about the ease and certainty of starting it up, training people, breaking old habits and establishing new good ones, and having the most difficult decisions completely handled with automation. It's that easy. There are no safety problems, and no high skills beyond the capacity of existing operators and maintenance people to learn."
Based on intelligent field instruments, open communication and operating systems, and modular software, PlantWeb architecture supersedes DCS (distributed control systems) and networks of PLCs (programmable logic controllers). It is readily scalable to handle automation throughout a TSD facility-from tank-farm operations to chemical processing.
"Originally, we had a budget based on traditional controls," Whitney added. "But then we found that PlantWeb architecture would actually save capital cost-not only the initial purchase but also the total package, including installation, startup, completion, servicing, and long-term operation. And we came in within budget, on time, with absolutely no startup problems whatsoever, and fully used all the little things that make it user-friendly and intuitive to the operators."
Rineco expects to extend PlantWeb architecture throughout the plant, including a projected large new chemical processing facility. As plant Manager Brad Cummock said, "To me, this is a fantastic change into the type of technology that is appropriate for this type of plant and this type of chemical industry."