RU2408544C1 - Method of purifying water from hydrogen sulphide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to technology of purifying natural underground water from hydrogen sulphide and can be used in treating underground water for supplying residential places. To realise the method, the water is saturated with atmospheric oxygen and filtered through a layer of a non-submerged catalytic load made from anthracite. Saturation of water with atmospheric oxygen is carried out simultaneously with filtration by creating continuous draught of an air stream through the layer of the catalytic load with grain size of 5-8 mm. Concentration of oxygen dissolved in water is kept equal to 8-9 mg/l. After filtration, the load is regenerated by filling it with water and alternately blowing with air in the direction of extension of the layer of the load with intensity sufficient for removing sulphur particles settled on the surface of the load.

EFFECT: method provides high rate of treating water with high concentration of hydrogen sulphide, reduces the size of filters and considerably cuts the area occupied by water treatment equipment.

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Description

The invention relates to a technology for purifying natural groundwater from hydrogen sulfide and can be used in the preparation of groundwater for water supply of settlements.

A known method of purifying water from hydrogen sulfide, including chlorination of water, followed by filtration through a layer of activated carbon (US 4264451, C02F 1/76, 1981).

The disadvantage of this method is that its use is limited due to the use of high concentrations of chlorine for the oxidation of hydrogen sulfide. In addition, the method is technologically complicated, as it requires the saturation of water with chlorine in airtight conditions.

A known method of purifying water from hydrogen sulfide, the closest in technical essence to the claimed one, comprising pre-saturating the purified water with atmospheric oxygen, followed by filtering through an unburied catalytic charge from anthracite (RU 2042644, C02F 1/58, 1994).

The disadvantage of this method is the low filtration rate (up to 1 m / h). Such a filtration rate provides water purification only for small settlements or for detached residential buildings, as it requires large diameter tanks and, accordingly, allocation of large land plots for water purification.

The task posed to the claimed technical solution is to increase the speed of water purification from hydrogen sulfide, which will result in a reduction in the area occupied by water purification equipment with an increased concentration of hydrogen sulfide, and lower equipment costs.

The problem is solved in that in a method of purifying water from hydrogen sulfide, including saturating it with atmospheric oxygen and filtering through a layer of non-flooded catalytic charge from anthracite, saturating water with atmospheric oxygen is performed simultaneously with its filtration by creating a continuous draft of the air flow through the pore space of the catalytic loading layer with fineness of grains 5-8 mm, with subsequent regeneration of the load by filling it with water and alternately purging the filled water with air in the direction reducing the loading layer with an intensity sufficient to detach particles of sulfur deposited on the loading surface and rinse it with purified water, followed by the resumption of the filtering process.

The inventive features of the method provide a technical result, which is manifested in an increase in the speed of water purification with an increased concentration of hydrogen sulfide. This result is achieved in the filtering process by increasing the number of sections where there is water wetting the catalyst surface and atmospheric oxygen coming from the atmosphere and there are no inter-pore sections completely filled with water. In the process of regeneration of the load, the complete removal of particles deposited on it and the restoration of its filtering ability are ensured, which, together with the claimed filtering mode, can reduce the size of the filters and significantly reduce the area occupied by water treatment equipment.

The method is as follows.

Underground water from the wells containing hydrogen sulfide is fed to an unfilled catalytic loading, for example, 1.2 m high, from high-grade coal of anthracite with an ash content of 3-5% and a grain size of 5-8 mm, placed in the filter housing. Water, by gravity, flows down the loading grains. Upon contact wetting of the catalyst surface by water, the hydrogen sulfide contained in it is uniformly oxidized with oxygen, which is supplied by continuous traction through the pore space of the air catalyst, created, for example, by the communication of the air medium before and after the loading layer with the atmosphere. It has been experimentally proved that the concentration of oxygen in water reaches 8-9 mg / L. This is enough to oxidize 20-30 mg of hydrogen sulfide in a volume of 1 liter. In this case, chemisorption processes occur on the wetted surface of the catalytic loading, due to electronic interaction, in which the elemental sulfur formed due to surface forces is retained on anthracite grains.

Oxidation of hydrogen sulfide by oxygen is represented by the following reactions:

H ₂ S + 0.5O ₂ = S + H ₂ O,

2HS ^- + 0.5O ₂ = 2S = H ₂ O.

On the surface of the electrically conductive body - catalyst loading - ions discharge occurs 2HS ^- molecules and H ₂ S to form sulfur and water.

The optimal values of grain size of anthracite grains of 5-8 mm, the height of the loading layer and the saturation of water with oxygen by air at the same time as it is filtered by creating a continuous draft of the air flow through the pore space of the catalytic loading layer increase the filtration speed to 3.5 m / h. Therefore, the filter performance increases by 3.5 times compared with the prototype. Increasing the filtration rate increases the flow of oxygen in the air, which, in turn, stimulates the cleaning process. Analysis of purified water showed that hydrogen sulfide was not detected in the filtrate. The surface of anthracite grains is covered with adsorbed colloidal particles of sulfur and other contaminants. The adhesion to the surface of the grains is strong and, in order to completely restore the properties of the catalytic loading, they perform operations for its regeneration. To do this, in accordance with the test analysis of purified water samples, the filtering process is interrupted, the charge is filled with water, for example, 200 mm above its level. Turn on air blowing in the direction from the bottom up with an intensity of, for example, 10 l / s · m ² , at which the load expands, the anthracite grains are intensively mixed and the sulfur particles are detached from the grain surface and transferred to an aqueous solution. After 5 minutes of purging, the blower is turned off and the pump is turned on, supplying in the same direction as the air clean water for washing the load with an intensity of, for example, 10 l / s · m ² for 3-4 minutes before clarifying the water.

The regeneration of the catalytic load using the claimed operations in conjunction with the filtering mode ensures the achievement of the above technical result. In addition, the inventive scheme of the regeneration of the load additionally saves purified water directed to its washing.

Claims (1)

A method of purifying water from hydrogen sulfide, including saturating it with atmospheric oxygen and filtering through an unburied catalytic charge from anthracite, characterized in that saturation of water with atmospheric oxygen is carried out simultaneously with its filtration by creating a continuous draft of air flow through a catalytic loading layer with a grain size of 5-8 mm, while the concentration of dissolved oxygen in water is equal to 8-9 mg / l, and after filtering, the charge is regenerated by filling it with water and alternating purging with air with an intensity sufficient to detach the molecules deposited on the surface of the sulfur load.