One of the riskiest and dangerous catalyst removal methods historically has had to do with hydrocracking. For decades, a problem with this method has been how to safely remove the catalyst by using an inert entry method.
The problem that makes this issue such a dilemma is the fact that the catalyst in hydrocracking is almost always tungsten mixed with nickel. At the time of manufacture, the catalysts are actually a very stable form of metal oxides. However, after they have gone through the activation process, they become sulfides. Chemically speaking, sulfides are highly reactive and therefore can be dangerously unstable. In fact, they are so unstable they can actually ignite when something as simple as being exposed to oxygen.
Not only does this make for a very dangerous situation, as the catalyst can ignite in close quarters or in situations that are direr, but they can also release a toxic compound known as sulfur dioxide. It is this problem which makes the need for a catalyst property management make perfect sense.
One extremely viable solution that experts within the industry found ways to use nitrogen to blanket the area when removing the catalyst. Why this works so well is really quite simple. The nitrogen replaces the oxygen in the area. This makes inert the possibility of the catalyst self-igniting because there is no oxygen to ignite it with. The catalyst can then be easily removed, placed in a container which is hermetically sealed, and then either disposed of, transported to a different location, or recycled somehow.
It is by using logical solutions such as these that the entire catalyst property management industry can learn. The safety flaws have been greatly reduced and the fatalities factors are all but non-existent by this crucial point in time.