CS254168B1 - A method of modifying geothermal water - Google Patents

Abstract

A method of treating geothermal waters by adding a system of substances that positively affect and prevent the incrustation of mining and distribution equipment with settled mineral substances, while increasing the inhibitory effect in terms of time and the overall effect of the incrustation barrier. In this method, a solution consisting of 4 to 10% by mass is mixed into the geothermal water. alkylaminopolyethoxyamer with 8 to 22 carbon atoms in alkyl and an average length of the polyethoxamer chain in the range of 5 to 25 basic units and 45 to 61 wt.%. ethoxypropoxamers of the general formula XO(EO)n(PO)m—H, where X is hydrogen or an alkyl group with 4 to 15 carbon atoms, while the n:m ratio is 1.2 to 1.5:1 and from 35 to 45% by mass. at least one polyphosphate with three to six phosphorus atoms, in a total amount of 1 to 20 mg/1 geothermal water

Description

254168 3

The invention solves the treatment of geothermal water by means of a system of positively influencing and preventing the encrustation of extraction and distribution devices by deposited mineral substances, whereby the inhibitory effect in terms of time and the effect of the incremental barrier is essential.

Geothermal waters are becoming more and more important in their national and agricultural spheres, and therefore more attention is being paid to their exploitation and exploitation. Extraction and exploitation of geothermal water is associated with a change in the chemistry of dissolved mineral substances. In geothermal water, Ca 2+ and HCO 3 "ions are present in increased amounts, and therefore a reversible reaction is taking place:

Ca? + + 2 HCO3- CaCO3 + CO2 + H2O - Due to decompression and degassing of the released CO2, the dynamic equilibrium is shifted to the right. The formation and dropping of CaCO3 increases with increasing concentration of the mineral content and the degree of supersaturation. The tendency to stabilize the calcium carbonate equilibrium persistently and exceeds the product of the solubility of CaCO3, forming the encrustation or precipitate of the Ca2h pumped from the solution.

The system of equilibrium states of geothermal waters is very complicated and complicated by the pressure, temperature, dissolved carbon monoxide, presence of bicarbonate alkali metals and alkaline metals. Dissolved gases, mainly methane, carbon dioxide and, rarely, hydrogen sulfide also play a significant role in this system. Chlorides which are converted by bromides, iodides, sulphates and silicic acid predominate from anions. Violation of only one indicator or physiological system results in its supersaturation and excessive calcium carbonate encrustation, which causes ingrowth of the distribution and exchanger tubes such that during a few hours, the thickness of the incrustation is formed in centimeters and during several days, the pipe diameter will be reduced to such an extent that the velocity of the flow in the incrusted pipe will drown and thus not be totally blocked.

Incrustations in the piping prevent transfer of heat through the walls of the tubes, forming a heat-insulating layer, thereby further reducing the utilization of heat from geothermal waters.

In order to remedy these shortcomings, he has proposed many solutions. For example, No. 188,605 teaches that geothermal water is mixed with 10 ° C colder carbonated water to maintain a chemical balance between dissolved mineral-containing gases.

Podlá čs. AO 236 299 injects into the geothermal water a solution of polyphosphate-based inhibitors in an amount of 1 to 30 gm-3 prior to releasing the dissolved gases.

Another approach is given by K. Rybický in Zborníkz z konference o utilizace geothermových vody v polohstva SSR, SVTS Bratlaslava, november 1977. According to this procedure, stabilization of equilibrium hold in chemistry of dissolved minerals after decompression ensures stabilization of large contents in which crystalline carbonate falls out In most cases, the heating system no longer produces further incrustations.

This procedure does not solve the problems of encrustation on the mining equipment above the gas evacuation point up to the stabilization tank.

Podlá čs. AO 236,405 is an inhibitor of alkali metal hydrogen phosphate and diphosphate, optionally combined with alkali metal hexamate.

U.S. Patent No. 3,633,672 uses organophosphorus types of inhibitors. U.S. Patent No. 4,782,469 discloses absorbent additives to prevent gyps formation.

In U.S. Patent No. 4,357,248, the inhibitory effect is based on the use of nitrogen-containing phosphonates.

USSR Certificate No. 842 054 provides a Ca 2+: P 2 O 5 ratio of 0.07 to 0.23.

As can be seen from the foregoing, some systems are not based on commercially available materials, whereas in phosphate systems, no inhibitory effect is ensured in a sufficient period of time or at an early stage.

Another known method for treating water overgrowth is magnetic adjustment.

According to Corosion Prevention and Control 29 (4), 15-18 (1982), the magnetic treatment could be referred to as a process that has been expanded under the name Hydrodinamic Fluid Treatments in many fields since the time of knowledge of this art. phenomenon in 1968.

The principle of magnetic water treatment is simple. Water containing dissolved substances kept in solution by gas has a tendency to form dense and hard deposits hot, permitting it through a relatively strong magnetic field formed in a narrow slit-permanent magnet or electromagnet. The solutes in the treated water are not excluded as hard encrustations, alumina or sludge, which is discharged from the device by the flowing liquid. Magnetic adjustment of geothermal water has not reached industrial utilization. Difficulties make magnetypre high volumes of mined geothermal water. As geothermal water is extracted from 80 to 95 ° C, magnetization is poor.

According to the present invention, the treatment of geothermal water by the addition of antifouling agents of the present surfactant-based mineral substances and poles-254168 5

Phosphates are carried out by introducing the geothermal water, under an aqueous solution of a system consisting of 4 to 10% by weight. C 8 -C 22 alkyl amine polyethoxyameate and an average length of the polyethoxamer chain in the range of 5 to 25 base units and 45 to 61 wt. ethoxypropoxameric formula

XO (EO) n (PO) m - H where EO is ethylene oxide, PO is propylene oxide, X is H or alkyl of 4 to 15 C atoms, the ratio n: m being 1.2 to 1.5: 1 to 35 to 45% by weight . at least one polyphosphate with three to six phosphorus atoms in a total amount of 1 to 20 mg / l of geothermal water.

In particular, the advantages of the process according to the invention include the high technical efficiency, the good and continuous method of dispensing, the commercial availability of the system components, their economical lowness and the concentrations used, as well as the hygienic defect.

The system used is metered into geothermal water, in the form of an aqueous solution, and it is expedient to use lower concentrations which allow more precise and continuous dosing of small quantities. From this point of view, it is expedient to use concentrations of 0.5 to 5% by weight.

As a rule, the system is introduced into the geothermal waters even in the mining section, most often in the area of evasion, but the system can also be used for application in geothermal water distribution systems. The proposed system has proven to be good even in corrosion tests, while corrosion tests have shown that corrosion does not exceed 0.1 mm / yr on the steel materials. Example 1

Into the borehole of geothermal water in the depth of 100 m in the evident area we add 3% aqueous solution in the amount of 1 mg / l, prepared from 5.5% by weight. dodecylaminopolyethoxyamer 10 mol. % ethylene oxide, 55 wt. of etoxypropoxamer, wherein the ratio of the bound ethylene oxide to the propylene oxide is 1.2: 1 and from 39.5% by weight. sodium hexametaphosphate.

The drawn geothermal water has a temperature of 90 degrees C. and a mineral content of 300 mg. I-1. 60 days of incrustation were not produced on the mining equipment as well as in the distribution pipes. There were signs of increased corrosion on the inner surface of the san

Into the borehole of geothermal water in the depth of 150 m in the evacuation area we inject 1.5% aqueous solution in the amount of 4 mg / l, prepared from 6.5% by weight. of a mixture of hexadecylaminopolyetoxamine with 15 mol. % of ethylene oxide and octadecylaminopolyethoxamer in a molar ratio of 1: 1, 58% by weight. ethoxypropoxamer, wherein the ratio of bound ethylene oxide to proxide is 1.5: 1 and 35.5% by weight, respectively. Sodium poly (phosphate / hexametaphosphate) mixture in a ratio of 1: 5 by weight. The geothermal water was the same as in Example 1. Incrustation was not produced on the production equipment after 150 days and there was no evidence of corrosion. Example 3

Into the geothermal water in the depth of 180 m in the area we introduce 2% aqueous solution in the amount of 18 mg / l of geothermal water, prepared from 8% by weight. of octadecylamino-polyethoxamer with 20 moles of ethylene oxide, 47 wt.% of ethoxypropoxamer in which ethylene oxide to propylene oxide is bound to 1.33: 1 and 45 wt. sodium hexametaphosphate. Geoiermal water was the same as in Example 1. No incrustation was obtained after 180 days on the mining equipment and there were no signs of increased corrosion. Example 4

Into the borehole of geothermal water we dispense 2% solution in the amount of 20 mg / l, prepared from 6% by weight. % hexadecylamino-polyethoxamer and 56 wt. etoxamer with bound ethylene oxide and propylene oxide at a ratio of 1.5: 1 and 38 wt. sodium hexaphosphate. An incrustation was formed on the extraction equipment, which was flushed with thermal water in the form of haze. Example 5

Inhibitors are used as in Example 4, but are introduced at a depth of 90 m. After 6 days, a 200 mg content has been observed. 1_1. Example 6

The procedure is as in Example 4, but the inhibitor is injected at a depth of 110 m. Example 7

Into the borehole of geothermal water we dispense a 2.5% solution in the amount of 12 mg / l prepared from 7% by weight. octa-cylaminopolyethoxamer with 15 moles. % ethylene oxide and 48 wt. of ethoxypropoxamer, in which the ratio of bound ethylene oxide to propylene oxide is 1.2: 1 and 40% by weight, respectively. tri-polyphosphate on the mining equipment was not incrusted even after 105 days.

Claims (1)

Process for the treatment of geothermal waters by the addition of anticorrosive agents based on surfactants and polyphosphates, characterized in that an aqueous solution of a system consisting of 4 to 10 percent by weight is introduced into the geothermal water under an evident depth. C8 -C22 alkylaminopolyetoxamer having an average polyetoxamer chain length in the range of 5 to 25 base units and 45 to 61 wt. of ethoxypropoxamers of general formula INVENTION X 6 (EO) _n (PO) _{m -} H where EC) is ethylene oxide, PO propylene oxide, X is H or an alkyl group having 4 to 15 carbon atoms, the n: m ratio being 1.2 to 1.5: 1 and 35 to 45 wt. at least one polyphosphate having three to six phosphorus atoms in a total amount of 1 to 20 mg / l of geothermal water.