Dispersing fines in hydrocarbon applications using artificial lift
View Patent ↗The lifetime of artificial lift systems, such as progressing cavity pumps (PCPs), used to transport aqueous slurries which contain fine particles, e.g. coal fines, may be prolonged by incorporation of at least one dispersant in the slurries. The dispersants act to inhibit or prevent the fine particles from agglomerating to plug the artificial lift intake and/or inhibit or prevent the agglomerated coal fines settling above the artificial lift system. The dispersant may also improve the lubricity of the slurry.
1. A method of dispersing fine particles in a slurry, the method comprising:
adding in any order:
water;
fine particles present in a range of from about 0.001 to about 0.5 wt % based on the total slurry, where the fine particles are selected from the group consisting of coal fines, shale fines, clay fines, iron sulfides, and combinations thereof; and
at least one dispersant selected from the group consisting of:
alkyl sulfosuccinates;
poly(ethylene oxide);
nonylphenoxypoly(ethyleneoxy)ethanol;
polyethyleneglycol alkyl-(C8C10)-ethers;
partially hydrolyzed poly(acrylamide);
hydroxyethyl cellulose (HEC);
quaternary nitrogen-substituted cellulose ethers;
xanthan gum, hydroxypropyl guar gum, carboxymethyl hydroxypropyl guar gum;
petroleum sulfonic acid derivatives, lignin sulfonic acid derivatives, naphthalene sulfonic acid derivatives, salts of these derivatives and formaldehyde condensates of these derivatives; and
combinations thereof; and
mixing the water, fine particles and at least one dispersant to give a slurry where the fine particles are dispersed therein.
2. The method of claim 1 where the amount of the at least one dispersant is sufficient to inhibit or prevent the fine particles from agglomerating as compared to an otherwise identical method absent the at least one dispersant.
3. The method of claim 1 where the amount of the at least one dispersant ranges from about 50 to about 10,000 ppm, based on the total slurry.
4. The method of claim 1 where the water is brine.
5. The method of claim 3 where the brine has a pH ranging from about 4 to about 10.
6. The method of claim 1 where the fine particles have an average particle size of less than 50 microns.
7. The method of claim 1 where the slurry has an absence of a wetting agent.
8. A slurry having fine particles dispersed therein comprising:
water;
fine particles present in a range of from about 0.001 to about 0.5 wt % based on the total slurry, where the fine particles are selected from the group consisting of coal fines, shale fines, clay fines, iron sulfides, and combinations thereof; and
at least one dispersant selected from the group consisting of:
alkyl sulfosuccinates;
poly(ethylene oxide);
nonylphenoxypoly(ethyleneoxy)ethanol;
polyethyleneglycol alkyl-(C8C10)-ethers;
partially hydrolyzed poly(acrylamide);
hydroxyethyl cellulose (HEC);
quaternary nitrogen-substituted cellulose ethers;
xanthan gum, hydroxypropyl guar gum, carboxymethyl hydroxypropyl guar gum;
petroleum sulfonic acid derivatives, lignin sulfonic acid derivatives, naphthalene sulfonic acid derivatives, salts of these derivatives and formaldehyde condensates of these derivatives; and
combinations thereof.
9. The slurry of claim 8 where the amount of the at least one dispersant ranges from about 50 to about 10,000 ppm, based on the total slurry.
10. The slurry of claim 8 where the water is brine having a pH ranging from about 4 to about 10.
11. The slurry of claim 8 where the fine particles have an average particle size of less than 50 microns.