SU1694518A1 - Method for obtaining superplasticizer - Google Patents

Abstract

The invention relates to the field of production for controlling the properties of concrete mixes and concrete and can be used in the process of producing superplasticizers by sulfonating naphthalene and further condensing it with formaldehyde. The purpose of the invention is to simplify the process and reduce the loss of naphthalene. When stripping residual naphthalene from sulfomass with live steam, the resulting gas mixture is bubbled through water at a temperature of 40 to 65 ° C. When this occurs, the desublimation of naphthalene in the form of flakes, on which further naphthalene capture occurs. The recovery rate is 90-98%. 1 tab.

Description

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The invention relates to the production of additives for controlling the properties of concrete mixes and concretes and can be used in the process of producing superplasticizers by sulfonating naphthalene and its further condensation with formaldehyde.

The purpose of the invention is to simplify the process and reduce the loss of blown naphthalene.

A known method of producing a superplasticizer is the condensation of naphthalene sulfonic acid with formaldehyde, followed by neutralization of the reaction mass with sodium hydroxide solution. The technological process is carried out according to a periodic scheme. In this method, naphthalene with concentrated sulfuric acid is first sulphurised. After sulphurization, the finished sulphmass is squeezed into the apparatus for stripping excess naphthalene. Stripping

Naphthalene is carried out at a sulfomass temperature of 125-130 ° C with live steam to a content of sulpholmass of no more than 1.5%. The naphthalene and water vapors from the stripping apparatus enter the steel lined packing column, which is irrigated with caustic soda solution with a temperature of 90-95 ° C. After removal of sulfur dioxide gas, the vapors enter the heat exchanger, where the superplasticizer is pumped from storage tanks to create a certain density of the aqueous solution (1080-1120). An aqueous solution of the specified density provides separation of the naphthalene-water emulsion. The dosage of the superplasticizer is produced with a rotameter. In the heat exchanger, vapor condensation occurs and the emulsion is cooled with water to a temperature of 70 ° C. Hot water is prepared in an apparatus equipped with a jacket for the heat carrier, with a thermometer. The water supply is carried out

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By pump, the dosage is made with a rotameter. The temperature of the hot water in the circulation circuit is maintained automatically by the instrument system: a resistance thermometer, an automatic balanced bridge, a valve on the wire to supply water to the jacket of the apparatus. Naphthalene emulsion with water from the heat exchanger enters the separatory funnel, where the emulsion separates. The top layer, crude naphthalene, enters the naphthalene collector, equipped with a jacket for heating with overpressure steam, a stirrer, a thermometer and a set of instruments for level measurement. As they accumulate, naphthalene is smelted from the sublimator by supplying steam with an overpressure of 0.3 MPa to heat exchange tubes instead of water. The melted naphthalene, after a certain number of otduvok with the Moaibio pump, is pumped into a measuring device for feeding to the sulfonation stage. The described naphthalene trapping scheme is very complex, in addition, some naphthalene is lost in the packed column and in the separatory funnel when the emulsion is separated from water.

In accordance with the invention, naphthalene is captured by passing vapor and acid gases from the stripping water through water with a temperature not lower than 40 ° C and not higher than 65 ° C. In the specified temperature range, naphthalene in the form of flakes occurs. Flaky naphthalene floating on the surface of the water is a porous filter on which naphthalene vapor is deposited. The degree of trapping under these conditions is 90-98%. When fiapoB is bubbled through water with a temperature below 40 ° C, desublimating naphthalene has a density greater than 1 kg / l and accumulates into two {apparatus, which leads to the overgrowth of barter rotor. The degree of trapping in this case due to vapor leakage is less than 60%. When the water temperature is above 65 ° C, a naphthalene emulsion is formed, which is mainly distributed in the upper layer. Due to the high vapor pressure and speed of their passage through the emulsion, the degree of trapping is 40–60% under these conditions. During the condensation of naphthalene in the form of an emulsion, an increase in pressure in the stripping line is observed, due to an increase in the height of the liquid column in the trap, which is undesirable for the process. These conditions are identical to those of the prototype.

When naphthalene desublimate with a developed surface after a certain

the number of otduvek poured water into a tank for neutralization. Naphthalene is melted by supplying steam to heat exchange tubes with an excess pressure of 0.3 MPa. The melted naphthalene after a certain number of otduvok using a pump is pumped into the measuring device for feeding to the stage of sulfonation. The amount of molten naphthalene is determined by level measurement.

When implementing the invention, a high degree of naphthalene trapping, pressure stability in the stripping line, simplifying the trapping method is achieved. When implementing the described method in

apparatus f 2400, H 3600 captures naphthalene by bubbling vapor through a pipe submerged in water 400 mm. The amount of naphthalene expelled in one operation is determined by analyzing the sulfomass for naphthalene content before and after stripping. In one operation, 300 kg of naphthalene are blown away. The temperature of the water is maintained through the circulation loop automatically by the instrument system: a thermometer,

automatic balanced bridge; valve on the wire to supply water to the jacket of the apparatus. The amount of naphthalene captured is determined by measuring the level after distribution.

Melting and pumping the naphthalene is carried out after 5 blows. The table presents data on naphthalene capture at different water temperatures.

As can be seen from the data presented in

in the table, when naphthalene is captured by passing vapor through water with a temperature of 50-65 ° C and desublimated flocculent naphthalene, the recovery rate reaches 90-98% (examples 2-4). In this case, water serves as a cooling agent, and flocculent naphthalene with a developed surface is a filter-precipitator.

Claims (1)

Invention Formula A process for preparing a superplasticizer comprising sulfonation of naphthalene with concentrated sulfuric acid in sulfuratore, stripping unreacted naphthalene by supplying acute steam into the apparatus and capture purged naphthalene polycondensation sulfonation product with formaldehyde and neutralizing the reaction mixture after the polycondensation, characterized in that, in order to simplify the process and reducing the losses of blown naphthalene, the latter is captured by passing its vapor through water with a temperature of 40 to 60 ° C.