Energy-Saving Process Automation

A process automation system at the heart of Industrial Furnace Co.'s (IFCO) industrial furnaces is using sophisticated motor control centers, PACs, networked I/O and reusable software code to streamline its control of multiple-hearth furnaces. A new program is also underway that uses heat exchangers to reclaim wasted heat and create power to offset a customer's natural gas costs.

IFCO is best known for its expertise designing, constructing and upgrading multiple-hearth (multiple-chamber) furnaces, ranging in size from 15 to 90 ft tall and up to 28 ft in diameter. Its latest system uses the PlantPAx(TM) process automation system from Rockwell Automation and system controllers configured using Rockwell Software(R) RSLogix(TM) 5000 software to reduce engineering time and streamline integration and troubleshooting.

Regardless of the application, most furnaces feature a similar design and the RSLogix software delivers significant value. The software uses a common tag-based structure that uses real names rather than physical addresses. Tag names can be shared between controller programs, HMI and other applications. By using the software's built-in instruction set and user-defined add-on instructions (AOIs), designers help save engineering time by creating their own commonly used library of code that can be tested once and used multiple times.

"The modular software code has proven to be a huge timesaver," says Mike Hilton, director of Electrical Instrumentation and Controls for IFCO. "Having faceplates for repeatable processes and functions reduces design time and allows us to get our systems to market significantly faster."

The library maintains logic blocks for each device, so the engineer only needs to determine how the device will work for a particular project. The engineer can then select the correct logic block to import into the program. Since the logic blocks integrate seamlessly with each other, the engineer only needs to import the proper function for each device and the software does the rest.

IFCO is also using Allen-Bradley CENTERLINE motor control centers (MCCs) with IntelliCENTER technology and networked I/O to help reduce wiring costs. Because the MCCs come equipped with integrated drives, the technician plugs in a cable and they're ready to go. To add a drive to a project, the engineer simply gives the drive a name and all the interfaces instantly appear.

"With the added flexibility of the PlantPAx system, we're able to very quickly make design changes on the mechanical and process end," Hilton says. "Also, the tag-based development environment allows us to do a lot of concurrent engineering design, helping us commission and start up a furnace in a couple of weeks rather than the typical three to six weeks."

In the past year, IFCO has been looking at energy efficiency as a new market. Because the air coming out of the furnaces is 1,300F, systems have typically quenched the hot air with water to bring the temperature down to 150F before moving into the scrubber system.

"Now we are offsetting the customer's use of natural gas by taking the energy wasted by injecting it with water, and instead creating power to offset the cost," Hilton says. "Our furnaces can produce as little as 500KW, or as much as 3MW of power for a plant. One of our customers that we are looking at will be able to produce enough power for the whole plant from one of our furnaces, so it's coming off the grid."

Hilton says there are more than 100 multiple-hearth furnaces active in industry to get rid of solids, and IFCO has already modified two furnaces that are doing some type of energy recovery. A 1MW system in New Haven, CT is online and has been running for four months.

"If we are able to take 1MW off the grid, that is a huge amount of savings for a small investment," he says. "There is funding available to help offset the cost with green and carbon credits, updating the process and furnace while at the same time also helping the environment.

Energy-Saving Process Automation