Issues with loading pre-sulfided hydrogenation refining catalysts?

A few years ago, I conducted research on presulfided catalysts; the precursor we used was ammonium tetramothiodate. During its decomposition, ammonium tetramothiodate releases hydrogen sulfide, and this hydrogen sulfide can be used to sulfide NI. The pre-sulfided catalyst only needs to be reduced in a hydrogen atmosphere for use; it has higher activity than catalysts that are re-sulfurized in their oxidized state, and it can reduce reactor corrosion.

1. I also use a pre-vulcanized catalyst in my installation; our facility uses nitrogen as the working medium for catalyst loading, and we employ specialized catalyst loading teams who have comprehensive equipment, with technicians also wearing their professional gear to enter the reactor for inspections. 2. Because the presulfided catalyst is coated with wax after being sulfured and loaded with a large amount of sulfur, during loading, the collision between particles causes the sulfur in the catalyst to be released; this sulfur then reacts with oxygen, generating heat. We have also encountered this situation; generally, when the temperature of the catalyst bed exceeds 50 degrees, nitrogen is introduced into the reactor to displace the oxygen present there. To ensure safe loading. 3. Our unit uses nitrogen as the working gas for filling, and the filling method is dense-phase filling. 4. We use wet vulcanization, employing sulfur carried within the material itself; vulcanization is carried out by raising the temperature through a specific heating scheme, which allows the sulfur to be released naturally. 5. Prolonged exposure of the catalyst to air causes significant loss of sulfur, leading to spontaneous reactions that affect the catalyst’s activity and its performance in use. 6. I think it is better to use pre-sulfided catalysts: a. The startup time is reduced b. Sulfurization becomes simpler c. Accidents caused by improper sulfurization are avoided d. Although loading is a bit more troublesome than the old method, it is safer. e. The effect after vulcanization is more ideal than that achieved by using sulfur from external sources

Preparations for catalyst loading: a) Preparations on the ground and outside the reactor: 1) Remove all obstacles from the area where catalyst loading will take place and clean it; 2) Place the equipment used for loading (loading platforms, forklifts, scales, etc.) in their proper positions according to the layout of the loading area. b) Handling and weighing of catalysts and ceramic balls: 1) Before filling, verify in the warehouse the specifications, types, and quantities of the catalysts and ceramic balls; 2) Weigh each bucket before filling and take samples; 3) After the ceramic balls and catalysts are delivered to the site, arrange them in the order specified for filling. c) Preparation of the reactor top: 1) Install the temporary platform and lifting equipment; 2) Install the charging hopper and charging equipment; 3) Remove the top cover flanges and elbow pipes and store them properly; 4) Introduce dry air into the reactor to reduce the oxygen concentration to above 20%. d) Preparation inside the reactor: 1) Once the oxygen concentration inside the reactor exceeds 20%, enter the reactor using a soft ladder, and remove and open the support grills, distribution plates, etc., layer by layer; 2) Clean the interior of the reactor and check the quality of installation of each layer of grills, tray surfaces, and various components; 3) Determine the appropriate filling height for the catalyst bed; 4) Remove any internal components that may interfere with catalyst filling, such as thermometer sleeves and cold hydrogen pipes; 5) The cold hydrogen pipes must undergo nozzle tests before they can be installed; 6) Install the equipment necessary for catalyst filling inside the reactor; 7) Make a list of all tools brought into the reactor, and check against this list after work is completed to prevent anything from being forgotten. Filling of ceramic balls and catalyst: a) The ceramic balls and catalyst are filled in accordance with the filling procedures provided by the research institute and the catalyst manufacturer; b) The weighed ceramic balls are transported to the ground work platform using a forklift, and then lifted to the top of the reactor using lifting equipment before being inserted into the reactor. Spread the ceramic balls in the reactor and level them out; c) Install the baffle for the catalyst discharge pipe at the bottom, and place the first layer of φ12mm ceramic balls as required; d) Place the second layer of φ6mm ceramic balls and the third layer of φ3mm ceramic balls as specified; e) Use a forklift to transport the catalyst to the ground-level workbench, then pour it into a bucket, make corresponding records, lift the bucket using a lifting device to the top of the reactor, and pour it into the filling hopper; f) Before starting the filling process, use instrument air to purge the reactor and keep it dry, while also introducing instrument air into the reactor to prevent moisture from entering it. The introduced instrument air should be blown upward above the catalyst bed; the airflow must under no circumstances pass through the catalyst pile. g) Inside the reactor, one person controls the slide valve, while one or two people hold the ends of the canvas tube and continuously push it in a circular motion to spread it evenly throughout the entire bed and keep it flat. As the thickness of the catalyst bed increases, the length of the canvas sleeve can be reduced by one meter at a time; h) Inside the reactor, it is forbidden to walk on or work standing on top of the catalyst, but work can be carried out on a support plate with an area of more than 0.3 m2. The support plate should be tied with a rope to prevent it from sinking into the catalyst pile. i) When the catalyst is filled to the position of the thermocouple, filling should be stopped, the thermocouple should be installed, and then filling with the catalyst can resume; j) When nearly the desired filling level has been reached, the filling speed should be reduced, and the mixture should be leveled regularly; if overload occurs, the excess material should be removed from the reactor using a small bucket; k) When 80% of the desired amount of catalyst has been filled, the volume and density of the catalyst fill should be calculated. Any deviation from the design values should be reported immediately; l) After the catalyst for the second bed is installed, place the ceramic balls on top of this layer as required, using the same method as for the bottom layer; m) Install the distribution plate and cold hydrogen pipes for the second layer; n) Install the first bed following the same procedure as for the second layer; o) After placing the Φ3mm ceramic balls on top of the first layer, place the scale-removal basket there and cover it with Φ6mm and Φ12mm ceramic balls; p) Once the ceramic balls are in place, install the distribution plate; q) Remove the catalyst loading funnel and take out all tools that were brought into the reactor; r) Reset the manhole: 1) Carefully inspect the gaskets and the sealing surfaces of the manhole, removing rust, dust, and foreign objects; 2) Fasten the manhole flange and bolts tightly, ensuring that the torque on each bolt is equal.

I would like to ask, what effects will there be in the later stages if the catalyst is not loaded properly?

I would like to ask, what effects will there be in the later stages if the catalyst is not loaded properly?