Dense loading of fixed bed catalytic reactors is a technique which has been used for a few decades, and has proven to be very useful for debottlenecking reactors and other vessels filled with particulate materials. It ensures the increase of the catalyst loaded and the improvement of bed homogeneity generating improved performances of the reactor. Today, PETROVAL has launched its new dense loading technology dedicated to large reactors: the Densicat® New Generation (DNG). It was developed keeping in mind three key points: safety, rapidity and quality.
The DNG machine consists of a stationary cylindrical body, supported as needed inside the reactor. The body serves to receive the catalyst from the top hopper via a sock, and to do the initial rough distribution of the catalyst. This initial partition is done via windows on the side of the machine body, and several openings at the bottom. The dimensions of these openings control the catalyst flow rate.
The machine body also houses the air-driven motor that is used to rotate the strip assembly, which is the main distribution device. This strip assembly is attached to the bottom of the motor, and turns the catalyst that is flowing out of the machine openings into a dispersed "rain" of particles.
The strip assembly consists for four layers of flat rubber flaps, attached to a central core. Each of the top three layers contains eight long strips and the bottom one only four short strips.
Six radar probes are installed on two arms and one in the centre to check, every time, the bed levelness. All datas are collected by the central control station where PETROVAL's engineer adjusts continuously the control parameters.
The DNG also has a vacuum system through the hollow shaft, to extract dust during the dense loading.
In accordance with PETROVAL's safety objective of zero accident, the DENSICAT® NEW GENERATION reduced drastically risks of accident. Thanks to the radars and the remote controller, nobody is inside the reactor during the catalyst dense loading. Also, the vacuum system eliminates catalysts dusts to protect workers around the reactor and improves the quality of the dense loading.
Radars permit to have a continuous overview of the bed profile during the dense loading. The operator outside the reactor can adjust in real time the DNG to correct the flatness of the bed. The quality of the loading is improved and the intermediary checks are avoided. The DNG was created with a potential loading flow rate up to 40 tons/hour, which allows a significant saving of time.