Integrate More Variables Using EtherNet/IP in Salt Mining Applications

Salt Mining Measurements Conforming to State Regulation

Plant Name:   Food Grade Salt Provider
Industry:         Food & Beverage
Product(s):     Finished Salt Product
 

Application

A large salt reserve located in Kansas lies between 400 and 800 feet underground. To retrieve the salt for processing, the operator will inject water into the ground to form a cavern. As water enters, saturated brine, at a specific gravity of 1.2, exits. The provider transports the brine to a plant, where it undergoes an evaporation process. 

As the cavern forms, operators will control the flow rates for steady development across several caverns, eventually flooding them together to form a “gallery.” Providers check caverns annually to ensure gallery development meets state mandates. Once they have developed or are close to completing a gallery, they will begin work on a new gallery.

Each cavern uses a flowmeter to measure the freshwater entering and the brine exiting (see image above). The provider drills a well into the formation and pumps water through the completed well to dissolve the salt, which returns to the surface as brine. The walls of the cavern are very resilient against reservoir degradation. Typically, every 1800-2100 gallons of fresh water pumped into a cavity will dissolve 265 gallons of halite (rock salt).

Challenges

To allow the salt provider to meet state salt mining requirements, the flowmeters must offer balanced measurements. Those ensure a balance between water entering and exiting the caverns. To be sure that proper calibration standards are maintained, the operator verifies the measurement accuracy.

In the past, the provider would manually calculate a balance using readings from all flowmeters. That required remote displays for each flowmeter, typically with a fiberglass enclosure to protect electronics. Each meter would also need to be frequently checked for calibration to comply with state requirements. Since the meter would be offline, that results in process downtime.

The salt provider searched for a better solution to gather more data from the cavern’s flowmeters while reducing the amount of manual data collection and time. In addition, management wished to reduce the cost incurred by installing the fiberglass enclosures for remote displays.

Solution

The provider decided to run piping from each cavern to the main building and installed the flowmeter’s remote electronics there. That would reduce the remote fiberglass enclosure cost but still did not resolve the increased data collection concerns.

After discussing those concerns with the Yokogawa representative, the provider installed Yokogawa’s ADMAG TI - AXG magnetic flowmeter (magmeter) with EtherNet/IP. The key benefit is that Ethernet/IP could handle large amounts of data at a higher speed than traditional analog signals. The provider can now integrate more variables into the control system for operators to maintain and monitor. Instead of walking from cavern to cavern and writing the totals to “balance” for the day, they can now bring this data forward to display a live balance. Additionally, the ADAMG TI offers an “adhesion” detection check, informing the operator if the piping is coating up.

To meet state requirements for calibration checks, the provider uses Meter Verification (part of the Total Insight concept of the ADMAG TI - AXG) to verify the calibration and functionality of each meter. The reliable accuracy of the AXG magmeter results from Yokogawa’s proprietary, dual-frequency excitation method. It combines traditional high/low-frequency excitation methods to ensure greater stability and quicker response even if noise or other problems are present in the line. With EtherNet/IP, the operator can initiate a verification from the HMI to ensure the gallery is running optimally.

The provider also purchased a pressure transmitter for each cavern. The transmitter monitors pressure on each of the lines and to use as diagnostics and other features.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Key Advantages

• Simplified set-up through remote access, faceplates, and PLC integration
• Fast data collection and simplified integration with PLC’s via EtherNet/IP communication
• Total Insight capabilities, including meter verification, advanced diagnostics, and offline trend analysis through a removable micro SD