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31.05.2021 A pneumatic conveying answer to a reactor filling challenge

Gericke, Regensdorf, Switzerland, has delivered a purpose-designed ergonomic reactor filling system utilising vacuum and positive pressure pneumatic conveying systems. The customer is a global player active in the speciality chemicals sector.

Several problems had to be overcome, including: how to load a reactor with the correct amounts of different powders, some displaying poor flow characteristics, without creating dust clouds, in a safe way for both the process and its equipment but also for the operators minimising material handling operations of the bulk raw materials.

Gericke was also faced with the challenge of unloading different powders delivered in small bags into several large reactors with volumes of more than 100m3. The traditional filling method of tipping directly above the reactor through an inlet would have required lifting all the bags from ground floor up to a height of more than 12m, thereby creating several potential safety and ergonomic problems.

The Gericke solution was to install a bag unloading station on the ground floor eliminating much of the bag handling by the operator. The large opening of the bag discharge station is designed to unload 20kg bags of a very light filter aid powder. During unloading bags into the tipping station, a vacuum conveying system, fed by a discharge screw installed at the bottom of the bag dump station, sucks the material away.  This allows even poor flowing powders to be emptied easily. The vacuum system transfers the powders from the bag dump station into a large receiving vessel. This vessel is on load cells so the weight is recorded and checked at all times ensuring that the correct batch weights are filled. The full recipe of powders is unloaded in this way with a total batch size of 50 – 400kg of all powders filled into the receiving vessel.

The vacuum receiver vessel then changes its function and operates as a pressure vessel suited for dense phase positive pressure conveying. A carrier gas, in this case pressurised nitrogen required by the process conditions in the receiving reactors, is used to transfer the material. Before starting transfer from the Gericke pressure vessel the receiving reactor is put under vacuum. The dense phase conveying system consumes only limited nitrogen so the scrubber on the reactor can be kept closed during the filling process reducing the vacuum in the reactor slightly.

The complete batch is emptied from the pressure vessel and filled into the reactors that are situated over 30m away from the dump station. With this arrangement the bag emptying area is isolated from the reaction area. With positive dense phase conveying systems conveying distances of more than 100m are feasible. During the project Gericke tested and proved the function of both vacuum and positive pressure dense phase conveying systems at its Regensdorf test facility.


Gericke’s reactor filling installation

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