PERIODICALLY CUTTING GEL INTO SEGMENTS, EXTRUDING AND DISSOLVING SEGMENTS

摘要

1441340 Forming gel solution HERCULES Inc 15 Feb 1974 [4 April 1973] 7051/74 Heading B5A [Also in Division C3] For the formation of an aqueous acrylic polymer gel into a solution, the gel is extruded from each of a plurality of orifices 52, of a die plate 44, as a strand of interconnected segments which are broken into particles, by a liquid delivered under pressure against the extruding strands and the outlet face of the die. The liquid acts to prevent agglomeration of the particles prior to their dissolution in a solvent, and may comprise a non-solvent such as methanol, but preferably comprises water, DMF, or ethylene glycol solvent in which the particles are dissolved by agitation. The gel is of stated preferred viscosity, and preferably comprises 5 to 50% polymer, and 95 to 50% water, and the solution may be employed as flocculants and as mobiliy control agents in oil recovery processes, particularly secondary and tertiary oil recovery processes. The examples relate to a co-polymer comprising 70% acrylamide and 30% sodium acrylate, with the liquid and solvent comprising water. The extrusion may be effected by a piston, or as shown by a variable speed screw of a pitch which decreases towards the die. The interconnected segments of each extruding strand result from the re-adhesion, during passage through the orifices 52, of the severing of each gel stream entering the orifices by a radial blade, or blades, 42 which is mounted to rotate with the screw 26 and sweep across the upstream face of the die plate 44. The liquid may be delivered from a single nozzle, or as shown from four nozzles spaced cimcumferentially around the die plate 44. The gel is delivered to the extruder as cylindrical pieces upon a slotted belt conveyer. Preferred values are specified of the die orifice size, of the total orifice area to that of the die plate, of the pressure at which the liquid is delivered, and of the particle size. The particles broken from the die are delivered into a tank (54), Fig. 1 (not shown), to which further solvent may be delivered to effect the solvation. A screw type pump delivers a slurry of particles in the solvent from the tank (54), through a series of tanks in which solvation is associated by low-shear and side entering stirrers. The solution may be filtered and may have additives added thereto.