Anti-agglomerants

A water-soluble white crystalline sofld, CS is disseminated as a spray, as a cloud of dust or powder, or as an aerosol generated thermally from pyrotechnic compositions. The formulation designated CSl is CS mixed with an anti-agglomerant when dusted on the ground, it may remain active for as long as five days. CS2 formulated from CSl and a siUcone water repellent, may persist for as long as 45 days (6). 

The use of kinetic inhibitors and/or anti-agglomcrators in actual fieid operations is a new and evolving technology. These are various formulations of chemicals that can be used in a mixture of one or more kinetic inhibitors and/or anti-agglomerators. At the current time, to get an optimum mixture for a specific application it is necessary to set up a controlled bench test using the actual fluids to be inhibited and determine the resulting equilibrium phase line. As the mixture of chemicals is changed, a family of equilibrium phase lines will develop. This will result m an initial determination of a near optimum mixture of chemicals. 

Thermodynamic inhibitors Antinucleants Growth modifiers Slurry additives Anti-agglomerates Methanol or glycol modify stability range of hydrates. Prevent nucleation of hydrate crystals. Control the growth of hydrate crystals. Limit the droplet size available for hydrate formation. Dispersants that remove hydrates. 

L. M. Frostman and J. L. Przybylinski. Successful applications of anti-agglomerant hydrate inhibitors. In Proceedings Volume. SPE Oilfield Chem Int Symp (Houston, TX, 2/13-16/2001), 2001. 

Z. Huo, E. Freer, M. Lamar, D. M. Knauss, E. D. Sloan, Jr., andB. Sann-igrahi. Hydrate plug prevention by anti-agglomeration. Chem Eng Sci, 56(17) 4979-4991, September 2001. 

For the polymerization of ethylene and propylene large-scale gas-phase processes are well established. The implementation of gas-phase technology to the production of sticky polymers such as the ethylene/propylene-based rubbers EPM and EPDM was pioneered by UCC [519]. In a series of patents, UCC describes various approaches to overcome the inherent stickiness of rubber granules in the gas-phase polymerization. These approaches include the use of anti-agglomerants such as carbon black, silica, inorganic salts or appropriate catalyst supports and antistatic voltage etc. [520-535]. The addition of fluidization or anti-agglomeration aids is described by Zollner et al., silica is used in particular [536,537]. 

Dispersant and pasting aid. Anti-agglomerate, effective with disperse dyes. 

International application published under the Patent Cooperation Treat (PCX). Gasification of biomass in a fluidised bed containing anti-agglomerating bed material. Int. Appl. No. PCT/FI99/00695. WO 00/1115, 2 March 2000 (02.03.00). 

The result obtained by the transmission electron microscope observations of the freeze-fracture replica on trehalose solutionssuggested that the ice-crystal nucleation is enhanced in the solution with higher trehalose concentration. Based on these experimental results and assuming a similar nucleation process between ice and clathrate hydrates, we can speculate that trehalose, as a kinetic inhibitor, may not inhibit the nucleation but may work as an anti-agglomerant, keeping small hydrate particles dispersed as they form. 

The inhibition effects of type-III AFP and trehalose, two cryoprotecting materials produced in animals, on type-I CO2 clathrate-hydrates were examined. For comparison with the results of a previous study in which the lateral growth rates of COi-hydrate film were dependent on temperature, pressure and NaCl concentration, the solution droplet was observed in a high pressure vessel filled with CO2. Type-III AFP was found to increase the induction period and to reduce the lateral growth rate of C02-hydrate films. It worked well at low concentrations, indicating that AFP works as a kinetic inhibitor. It was also indicated that AFP would weaken the memory effect of C02-hydrate formation. Trehalose had similar inhibition effects on both the induction period and the lateral growth rate, but it had little apparent concentration-dependence on them. Since trehalose also causes the equilibrium conditions of the CO2 hydrate to shift to lower temperatures, it works not only as a thermodynamic inhibitor but also as a kinetic inhibitor, especially as an anti-agglomerant. 

A method of solving many coagulation anti agglomeration problems (Chapter 8) has been developed based on the use of a similarity transformation for the size distribution function (Swift and Fricdlander, 1964 Friedlander and Wang. 1966). Solutions found in this way are asymptotic forms approached after long times, and they are independent of the initial size distribution. Closed-form solutions for the upper and lower ends of the distribution can sometime.s be obtained in this way, and numerical methods can be used to match the solutions for intermediate-size particles. Alternatively, Monte Carlo and discrete sectional methods have been used to find solutions. 

Sisellig. [Ceca SA] Antislip, anti-agglomerant for fibm. 

The novel and perspective field of tubular turbulent apparatus application is the carrying out of fast chemical processes with formation of solid phase. This provides wide possibilities for modification of metal-complex Ziegler-Natta catalytic systems at the expense of hydrodynamic influence on disperse structure of micro-heterogeneous catalysts particles, receipt of high-effective anti-agglomerates for synthetic rubbers, etc.. 

Kinetic inhibitors are used on a smaller scale ( 0.5 %) and work by reducing the rate at which the hydrate is formed. The small amounts of hydrate that do form are simply carried along in fhe flow and dealt with at a later stage in the refinement process. Kinetic inhibitors are usually polymeric organic materials, such as poly(vinyl pyrrolidinone) (PVP). Generally, kinetic inhibitors or other anti-agglomerants (such as tetraalkyl ammonium salts) are not used without the presence of a thermodynamic inhibitor as well. 

Uses Dispersant, protective colloid, dyeing assistant esp. for exhaust dyeing of polyester stabilizer for dye dispersions anti-agglomerant for vat, naphthol, and disperse dye particles... 

Uses Surfactant, color enhancer/anti-agglomerant for pigments in painis/coatings, textile printing and fiber finish o/w emulsifier pigment stabilizer Features Reduces and prevents agglomeration of pigments Properties Yel. liq. dens. 1.014 g/ml vise. 385 cP HLB 10-12 pour pt. -20 C cloud pt. < 0 C surf. tens. (1% actives)32 dynes/cm Ross-Miles foam (0.1%, initial) 10 mm 100% act. 

Uses Backstaining reducer, dispersant, antiredeposition agent for desizing and cellulase abrasion processes dispersant, anti-agglomerant, antisealant, antiredeposition agent for process/solubilized contaminants Features Compat. with a-amylase and cellulase enzymes used in garment processing nonflamm. 

Uses Dispersant, anti-agglomerant for dyestuffs, preventing spots during dyeing Dextrasperse COM-100 [Ashland/Aqualon]... 

Uses Dye dispersant/anti-agglomerant cationic dye remover for acrylics or polyesters and their blends with wool... 

---