What do soldiers, firefighters, coal miners and underwater divers have in common with workers performing fixed bed inert catalyst changeouts? Technology.
For more than 30 years, the equipment and procedures used to remove and replace solid catalyst in fixed bed reactors remained essentially unchanged. But now the industry is transforming and modernizing. Aided in large part by technology transfers from other industries, inert catalyst changeout projects are becoming substantially safer and more efficient. Here are some of the innovations that are advancing the state of the art.
Biometric monitoring
For inert catalyst projects, the greatest challenge is assuring personnel safety during catalyst removal. Technicians must enter confined, oxygen-deficient process vessels to dislodge and vacuum the catalyst. It is strenuous manual labor performed in a toxic, potentially combustible atmosphere surrounded by nitrogen gas.
Fortunately, new biometric monitoring systems are revolutionizing the ability to track the health and well-being of technicians inside a reactor. In the past, supervisors had to rely on subjective evaluations. Now they have hard data. Technicians are fitted with special monitoring belts underneath their PPE that gather and transmit key vital signs. Designed by the U.S. military and used by a growing number of fire departments, these systems monitor heart rate, respiratory rate, core body temperature and body position. Supervisors track the data and make sure technicians leave the reactor when their vital signs approach a predetermined baseline. Biometric monitoring has proven effective in preventing overexertion, heat exhaustion and injuries.
Surveillance, communication and control
Inside the reactor, technicians wear standard PPE, a disposable coverall and a NIOSHcompliant, lock-on helmet. A life-support umbilical — similar to those used by underwater divers — includes two air lines, a communication line and an aircraft cable as a backup in case an incapacitated technician needs to be winched out of the reactor. Now, communication and surveillance are improving. Non-IDLH (immediately dangerous to life or health) low-pressure equipment used by technicians outside the reactor allows technicians to talk with each other and with supervisors in the control room via clear, hands-free communication. In addition, dual high-resolution camera systems provide not only the technician’s perspective of the work but also an overview of the technicians in the confined space.
Control room modifications are also enhancing safety. Special locking air-control handles prevent accidental interruption of air to technicians. Once an air line is opened, only the technician using that air line has the key to open the lock. Control room computers are being upgraded to include weather monitoring systems with Doppler radar to allow proactive measures when lightning and adverse weather approach. Throughout the operation, dual components and systems are being added to provide redundancy on everything from temperature probes to cameras.
Carbon dioxide injection
Catalyst removal is faster if the material is free-flowing. If fused and hardened, it can double the amount of time spent in the reactor and require virtually nonstop jack-hammering. Fortunately, non-detonating carbon dioxide gas expansion fracturing — a technology adapted from mining and cement kiln operations — offers a safer solution.
This technology creates a powerful, highly controlled force that dislodges rock-hard catalyst deposits without creating high-velocity shock waves or damaging the vessel. Because it poses no fire hazard, the technology is widely used in applications where dust, chemicals or combustible materials are present. Special charges are placed through the reactor dump nozzle and set off remotely while workers remain outside the reactor. The charges produce a controlled release of liquid CO2 at up to 34,000 psi to break up deposits and allow catalyst to flow easily, reducing in-vessel man-hours and minimizing risk.
While there is no substitute for proper planning, training and experience, incorporating proven, related technologies is leading to remarkable advances in safety and risk management.
For more information, visit www. USADeBusk.com or call (844) 243-5557.
