Atex 20 Loading of resins and polymers in chemical reactors under pressure

Processed powders: maleic anhydride with an actual density of 1,310 kg/m³, Epo Kukdo, DER 671 with an actual density of 1,180 kg/m³

Resin and gel coat manufacturing 

The customer is one of the world leaders in the production of structural resins for the building, automotive, water sports and leisure industries. The company is also a major player in the markets for decorative and glaze paints, coatings, inks, graphic arts and adhesives.

The customer requested a line for the controlled feeding of their reactor, at a rate of 4 tons/hour, of raw materials of high density and capable of being strongly mass solidified. All equipment must comply with ATEX directives.

Bag and big bag deconditioning station
Palamatic Process supplied an EasyFlow® EF01 big bag emptying station that allows the big bag to be installed from an electric hoist and a handling cross on the dispensing platform with sealing skirt. The operator opens the stripping box and undoes the big bag knot to enable the big bag to be discharged. Six large diameter pneumatic cylinders apply pressure to the lower and lateral parts of the big bag to facilitate the flow of the bulk materials, which is strongly massaged.
A knife lump breaker is positioned under the stripping box to break up any clods that may have formed in the big bag. It is provided with eight blades mounted asymmetrically on a very high-strength shaft. This shaft is driven by a gear motor with a very high torque, which reduces very hard clods to a size acceptable for pneumatic conveying.

In the meantime, a bag emptying station, the Sacktip® S model, is installed to unpack the bags. The operator opens the door (supported by gas springs that accompany its opening and closing) and places the bag on the tablet. He then places it on the screen, which is placed above the powder discharge hopper, and can then manually open the bag and empty it. The powder discharge 200 liters hopper of the bag emptying station is provided with two pneumatic hammers and four vibrators that help bulk materials that are difficult to discharge. A dust extraction system is flanged to the bag dump station and a nozzle cleaning system is installed on each cartridge. A chute fitted with a polyethylene bag allows the bags, once emptied, to be evacuated, avoiding the spreading of dust once the operation is completed.

Powder conveying
In order to convey the bulk materials from either depacking station to one of the two reactors, a set of two switches, which are controlled by the operator from the control panel, is mounted on the conveying pipes.
The raw materials are pumped through the VFlow® 05 dense phase vacuumed pneumatic transfer system. The conveying rate of the raw materials is 6,100 liters/hour. The pneumaticvacuum conveying system works on the principle of the high vacuum depressor. The receiving cyclofilter connected to the reactor, cyclones the discharged powder and thus carries out the air/product separation. The highly efficient filter integrated into the cyclone ensures the final separation of the air and the protection of the vacuum pump (suction unit). A compressed air cleaning system allows the filter to be cleaned at each change-over.

Loading of reactors
The VFlow® 05 conveying cyclones are equipped, in the lower part, with a slide valve that allows the entire line to be evacuated and the supply of bulk materials to be cut off on demand. A capacitive level sensor is used to detect the presence of the bulk material at high level and to stop its arrival by controlling the slide gate valve.
A volume nozzle, equivalent to that of the cyclone, forms a chamber between the reactor valve and the cyclone valve. As soon as the probe is covered, the cyclone inlet valve closes, the bottom valve opens and a high nitrogen pressure is sent through the filter to force the downflow to the reactor and avoid the pressure build-up in the cyclone.