A method for producing naphthalene-based water-reducers by centralized sulfonation and meal-divided condensation by solvent method

Abstract

The invention provides a method for solvent method centralized sulfonation separate type condensation production of a naphthalene water reducer. The method includes the steps of putting, sulfonation, dehydration, hydrolysis, condensation, neutralization and the like. By adopting a low acid blending amount for sulfonation, no disulfonic acid or polysulfonic acid is generated, the selectivity of beta-naphthyl sulfonic acid is improved, the quality of the water reducer is improved, and the emission of waste residues is reduced; solvent is used in the sulfonation process, the water outlet amount serves as the reaction endpoint target value, the solvent amount for each time of dehydration is gradually reduced, the solvent use amount is reduced to the maximum, and thus the heat loss is reduced; a large-volume reaction kettle is adopted for centralized sulfonation, reaction released heat is fully utilized, the temperature of the reaction kettle is kept, and the steam use amount is reduced; the emission of waste gas is reduced; condensation is carried out without pressure, and thus safety is high.

Description

technical field [0001] The invention relates to the technical field of concrete admixture production, in particular to a method for producing naphthalene-based water-reducers through centralized sulfonation and meal-dividing condensation by solvent method. Background technique [0002] Water reducer is a concrete admixture that can reduce the amount of mixing water while maintaining the slump of concrete. Most of them are anionic surfactants, such as lignosulfonate, naphthalenesulfonate formaldehyde polymer, etc. After being added to the concrete mixture, it can disperse the cement particles, improve its workability, reduce the unit water consumption, improve the fluidity of the concrete mixture; or reduce the unit cement consumption and save cement. [0003] Naphthalene-based water reducer is a widely used high-efficiency water reducer. It is a superplasticizer with good water-reducing and early-strength effects. It is mostly used in the concrete industry, and is also used...

AI Technical Summary

Problems solved by technology

Its production process is mainly to put industrial naphthalene into the reaction kettle, heat up to a certain temperature, add concentrated sulfuric acid dropwise while stirring for sulfonation, keep warm, hydrolyze, add formaldehyde to condense, neutralize, and dry. At present, the general production method The sulfonation is carried out in a 5 cubic reaction kettle. After the sulfonation is completed, formaldehyde is condensed dropwise in the same reaction kettle. This operation has the following four problems: (1) In large-scale production, due to the alternating refrigerant and heat medium (2) The heat loss in a single batch operation is serious, and the heat released by the reaction is not fully utilized; (3) The reaction area is large, and the exhaust gas volatilizes a large amount; (4) The production efficiency is low, and continuous production cannot be realized; (5) When industrial naphthalene is sulfonated with sulfuric acid, especially when high-concentration sulfuric acid is used, such as 100%, 105%, 120% and other high-concentration concentrated sulfuric acid, the concentrated sulfuric acid cannot be dispersed in time, and it is easy to produce di Sulfonic acid or polysulfonic acid reduces the selectivity of β-naphthalenesulfonic acid, affects the next step of formaldehyde condensation, and affects the quality of the water reducer

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