Wireless instrumentation is proving its worth and overcoming objections in the heavily regulated and often conservative pharmaceutical industry.
The pharmaceutical and life sciences industries are very conservative, and with good reason. Control and monitoring of batch and continuous manufacturing processes are closely regulated and validated by various FDA rules and regulations, and control engineers are reluctant to adopt any new technologies that might threaten those approvals. They are also very concerned with final product quality—and, therefore, often tend to stick with the tried and true.
For these reasons, relatively new wireless instrumentation technologies have not been applied as quickly in the pharmaceutical industry as in other process plants, where their acceptance has been rapid and widespread. But this situation is changing, as the advantages of wireless are overcoming perceived risks.
Wireless Proves Its Worth
Flow, pressure, temperature, level, and other instrumentation in a typical batch reactor or process system in the pharmaceutical industry is almost always wired. That is, each instrument has a 4-20 mA two-wire or a fieldbus connection that runs through cables to a termination point in a marshalling cabinet, and from there to control and monitoring systems. “We know wired systems work,” said one Emerson contract manufacturing organization (CMO) customer. “Wireless might be OK for other less critical processes, but we can’t take the risk.”
The CMO customer had other objections including worries about dropped signals, update rates, reliability, battery life, and how to connect a wireless signal into his DeltaV distributed control system.
But this all changed when the CMO was developing a new process using six small floor-mounted batch reactor vessels for one of its Big Pharma clients. They needed to monitor temperatures and level in the vessels, and send this information to their control system. The biggest problem was that the pilot plant was in a room with no accommodations for new instrumentation wiring. To install conventional wired instruments, they would have to run conduit and pull wire, which would require excessive cost and time. To alleviate these issues, they decided to try wireless.
The company purchased and installed one Rosemount wireless hygienic point level switch and one wireless temperature transmitter at each of the six vessels, along with a single wireless gateway for connection to the twelve instruments.
The wireless transmitters send data over a WirelessHART mesh network to the gateway, which interfaces with the control system via a hardwired Ethernet connection. Because the control system includes native support for both wired HART and WirelessHART protocols, mapping information from the instruments to the control system’s data registers was straightforward, essentially a plug and play operation.
The wireless instruments, network, and gateway worked flawlessly from the beginning and continue to do so, allowing the CMO to provide real-time control and monitoring of the reactor vessel batch processes.
Building on the success of the first project, Emerson and the CMO are now in the process of installing wireless instrumentation for an elevator system. Materials on the elevator must be maintained at a constant temperature for 1.8 minutes as the elevator moves up and down. The system will have 30 wireless temperature transmitters connected via WirelessHART to the control system. Wireless is much simpler and less expensive than wired in this case as it would be extremely difficult to build and maintain wiring harnesses which could move up and down with the elevator and retain a reliable connection with the control system.
The applications above are for a CMO pilot plant. Another area where wireless could be quite effective is process development (PD) labs. These labs are used extensively in the life sciences industries to conduct experiments on various drug compounds. The goal of PD is to produce optimized, robust, and reproducible processes that can be scaled up for manufacturing, first in pilot plants, and then in end user manufacturing facilities.
Currently, many PD labs are not fully automated. Many experiments are still run manually, with data recorded via pen and paper. Some labs have automated certain areas, but have yet to network their islands of automation into a coherent system, leading to poor productivity and other issues.
But some PD labs have upgraded to fully automated and networked control—dramatically improving lab productivity, increasing experimental run success rates, reducing labor and equipment resource requirements, and significantly enhancing the data packages used for tech transfer.
One way to automate these labs is with wireless transmitters (Figure 1), thus eliminating the cost of wiring, power supplies, and cabling to a control and monitoring system. Instead, battery-powered WirelessHART flow, level, temperature transmitters can send data to a gateway, and from there to control and monitoring systems.
Production in most PD labs is limited by a lack of qualified personnel. Investments in automation allow existing personnel to run more successful and statistically valid experiments will produce a quick ROI.
Out in the Plant
Wireless transmitters are widely used in the chemical, oil & gas, power, and other industries to monitor equipment such as steam traps, pumps, remote facilities, and similar systems—all of which also exist in pharmaceutical plants. The great advantage of wireless is that it doesn’t require the expensive, complex infrastructure of a wired 4-20mA or fieldbus system. A battery-powered wireless transmitter can be installed almost anywhere, and it automatically connects to a control system via a gateway.
For example, clean steam is widely used in the pharmaceutical industry for sterilization of products and equipment, such as with clean-in-place processes. Steam is also used in the production processes for many end products. If a steam trap fails open or closed, it can interrupt the process, leading to a complete shutdown of a batch reactor or a process unit, which could completely ruin an expensive batch of product.
The best solution for monitoring steam traps is to install wireless acoustic transmitters (Figure 2) on critical steam traps and analyze their data with specialized software. A plant operated by large engineering and construction company had these types of steam trap issues. Its audit showed that 25 percent of the steam traps were failing for unknown causes.
The company installed wireless acoustic transmitters on 187 steam traps and 63 pressure relief valves. “A simple cost analysis based only on energy savings showed the installation of the steam trap monitoring system was easily justified because the solution paid for itself within one year,” said a company engineer. “Not to mention the savings from avoiding equipment damage, and avoiding safety or environmental incidents.”
A pharmaceutical plant has hundreds of pumps that move product and materials. As with steam traps, if a critical pump fails, it can shut down a process. Once again, wireless transmitters can detect pump problems and alert maintenance that a pump needs attention before it fails.
Vibration monitoring detects many common causes of pump failure. Excessive motor and pump vibration can be caused by failing concrete foundation or metal frame, shaft misalignment, impeller damage, pump or motor bearing wear, and/or coupling wear and cavitation. Increasing vibration commonly leads to seal failure and can result in expensive repairs, process upsets, reduced throughput, fines if hazardous material is leaked, and fire if the leaked material is flammable.
Cavitation monitoring is needed on high head multistage pumps as they cannot tolerate this condition for even for a brief period of time. Although cavitation often happens when pumps operate outside of their design ranges, it can also be caused by intermittent pump suction or discharge restrictions. Wireless pressure transmitters on a pump can detect cavitation.
A complete pump health monitoring system involving wireless vibration, pressure, and flow transmitters can pay for itself in a matter of months. At one 250,000 bpd refinery, for example, pump monitoring systems were installed on 80 pumps throughout the complex. The annual savings was over $1.2 million after implementing the pump monitoring solution, resulting in a payback period of less than six months. The savings came from decreased maintenance costs of $360,000, and fewer losses from process shutdowns because of failed pumps which were conservatively valued at $912,000.
Although some areas of the pharmaceutical industry are very conservative and slow to adopt new technologies, its engineers are increasingly looking to other industries to see how wireless transmitters have been used successfully and applying the results to their own processes.