Some of the best relationships grow slowly and get warmer over time, even if they experience some bumps along the way. Such is the case with Hunt Refining Co., which cautiously adopted wireless for maintenance about six years ago, and came to appreciate it in a variety of monitoring, reliability, optimization and safety applications.
“It’s been a long journey since 2007, but from early adoption of a pre-standard wireless solution to aiding development of future Emerson products, Hunt Refining truly blazed a wireless trail,” says Alan Weldon, technical services and safety director, Hunt Refining. “I initially said I didn’t want to do wireless, but our maintenance manager decided to try it, and generated savings. So, we began to try wireless in other areas, and now I’m a big wireless advocate.”
Weldon and Donna McClung, executive field engineer, Emerson, and Steve Moore, wireless specialist, Emerson, presented “From Resistance to Enthusiasm: A Wireless Odyssey” on the second day of Emerson Global Users Exchange 2016 in Austin, Texas.
“Our initial resistance was due to concerns of network reliability, security and integration into the existing DCS,” adds Weldon. “However, acceptance grew as the wireless network was expanded to include many pervasive sensing applications that address safety, environmental, reliability and process needs across the refinery.”
Wireless growing pains
Hunt began using wireless shortly after Emerson introduced its version in 2007 to monitor tank temperatures in a remote location. “Potential savings overcame initial resistance, and we installed three Rosemount 648 wireless temperature transmitters along with a 900-MHz 1420 Gateway and four additional 648s as repeaters,” Weldon explained. “However, we also had some bumps in the road.”
Wireless temperature monitors were added to more tanks the following year, but some power modules had to be replaced after less than a year of service. Weldon’s staff and their colleagues from Emerson determined that the existing, 900-MHz wireless network was experiencing “choke points” with too much data trying to pass through one device. Also, battery life issues caused a delay in installing more wireless temperature monitoring.
Standards and solutions
These wireless hiccups began to be resolved in 2009 when Emerson’s Rosemount division adopted the WirelessHART protocol, and Hunt upgraded to a newer, 2.4-GHz WirelessHART gateway. AMS and Wireless Snap-On were also added to address network stability and reliability concerns. “This made the upgrade easy and successful,” said Weldon. “So when overfill protection was needed on a remote ethanol tank, we installed a Rosemount 702 Discrete Wireless Transmitter to a two-point float switch.”
Then, to improve equipment reliability in 2010, Hunt implemented Rosemount 648 temperature transmitters on critical heat exchangers. And, to address environmental compliance, it added Rosemount 3051CD DP and 648 temperature transmitters to monitor water flow and temperature going to the nearby Black Warrior River.
In 2011, Hunt added a THUM wireless adapter on a 3051 SMV transmitter to meet 40 CFR 98 reporting requirements for greenhouse gases. Following its success, THUM was added to a Micro Motion Coriolis meter measuring asphalt to a coker for density and mass flow data. However, intermittent communication issues delayed installation of additional THUMs. “That added some angst,” said Weldon. “But the difficulty was finally identified as a wiring issue, and it was repaired.”
More recently, Hunt installed six Rosemount 708 acoustic transmitters on its Butane Bullet relief valves in 2013. These notify operators if a relief valve is beginning to relieve or leak. In 2014, the refinery added three Rosemount 848 high-density temperature transmitters on diesel hydrotreater and combined feed exchangers.
In 2015, Hunt upgraded its wireless gateways to Version 4.0, which was required to install a Permasense corrosion monitor and 20 sensors in coker and crude unit. Also, a THUM was added to a Micro Motion meter on a crude feed tank to monitor flow, temperature and API gravity, and a CSI wireless vibration monitor 9420 was added to coker jet pumps. “Finally, this year we added Micro Motion’s high-capacity ELITE Coriolis Meter with THUM to our oil movements area for custody transfer of asphalt,” said Weldon.
“Out initial resistance to wireless was overcome by its demonstrated network and transmitter reliability, as well as the improved diagnostics from AMS and Wireless Snap-on. Our acceptance resulted in non-traditional monitoring applications in environmental, reliability and safety. So far, we have a total of 77 Emerson wireless devices and 20 third-party devices installed. The takeaway is when we look at an application now, we immediately ask if we can do it with wireless.”