Solution polymerization method

Abstract

The invention provides a solution polymerization method. The solution polymerization method comprises the following steps that an aqueous solution containing monomers and sodium hydrosulfite contact under oxidation reaction conditions; and after contact, the mixture is mixed with a persulfate under the conditions of acrylamide low-temperature polymerization, wherein the monomers comprise 75 to 100 mol% of acrylamide and a mole ratio of oxygen dissolved in the aqueous solution to sodium hydrosulfite is 1: (0.4 to 2). The solution polymerization method can avoid a process of nitrogen-filling oxygen-removal of an aqueous solution containing monomers, eliminate an inhibition effect produced by oxygen dissolved in the aqueous solution on monomer polymerization, realize preparation of an acrylamide polymer having ultra-high molecular weight, and greatly reduce polymerization time of acrylamide polymer preparation.

Description

technical field [0001] The present invention relates to a solution polymerization method. Background technique [0002] Acrylamide polymer is currently the main oil-displacing polymer used in tertiary oil recovery in oilfields. It has a good oil-displacement effect on type I oil reservoirs with low temperature and can greatly improve oil recovery. However, for Type II and III oil reservoirs with high temperature and salinity, in order to prepare ultra-high molecular weight acrylamide polymers in the prior art solution polymerization method, it is necessary to first purify acrylamide and other monomers to obtain the viscosity average molecular weight About 20-30 million acrylamide homopolymers (the viscosity-average molecular weight of unpurified acrylamide homopolymers is only 6-10 million), this acrylamide polymer is used as an oil displacement agent in high salinity and high The oil displacement effect cannot be obtained at high temperature; there are also studies using 2...

AI Technical Summary

Problems solved by technology

The method has the characteristics of simple operation, safety and economy; but the above-mentioned traditional acrylamide polymer preparation method cannot obtain ultra-high molecular weight acrylamide polymer, and the induction period of the initiator in the above-mentioned method is relatively long, and the entire acrylamide polymerization The preparation process takes a long time

The reasons are: (1) Acrylamide, AMPS, etc. as monomer raw materials inevitably introduce a small amount of high-valent metal ions, polymerization inhibitors and other substances in the production process, which are not conducive to obtaining ultra-high molecular weight acrylamides. polymer; (2) The existing nitrogen filling and deoxygenation operation cannot sufficiently remove dissolved oxygen

In addition, the use of polymerizable surfactant monomers (such as methacryloyloxyethyl dimethyl benzyl ammonium chloride, (2-acrylamido) ethyl tetradecyl dimethyl bromide, etc. ammonium chloride) to modify acrylamide polymers, so that the modified acrylamide polymers can achieve better oil displacement has become a research hotspot, but nitrogen filling will make the aqueous solution containing surfactant monomers with polymerization ability A large number of bubbles are generated, therefore, the traditional nitrogen filling and deoxygenation operation cannot solve the deoxygenation problem in this type of polymerization system

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