SU1756281A1 - Device for desorption raising of sea water containing hydrogen sulfide - Google Patents

Abstract

The essence of the invention: the device includes a pipeline with a cylindrical confuser placed at the bottom and connected to the positive pole of the current source. A cylindrical bushing is installed inside the confuser, connected to the negative pole of the current source. The confuser is separated from the sleeve by a diaphragm, in the upper part of which a valve for gas outlet is placed. 1 il.

Description

The invention relates to subsea mining of minerals from the depths of the sea and provides for the allocation for subsequent use of gases, such as hydrogen sulfide, dissolved in water.

A disadvantage of the known device is the additional consumption (supply) of carbon dioxide for saturation of sea water, the high consumption of material for the manufacture of two concentric pipes, which complicates the process of raising sea water from depth.

The purpose of the invention is to increase the degree of desorption of dissolved gases.

The method of extraction is as follows.

The device lowered into the sea is filled with seawater. Upon reaching the required depth, a constant electrical voltage is applied to the electrodes. Since seawater is an electrolyte, the movement of ions (cations to the cathode, anions to the anode) begins between the cathode and the anode through a canvas septum. After some time, an acidic medium forms in the anode area, as a result of which an intensive release of hydrogen sulfide begins. The released hydrogen sulfide as it rises along the device creates a difference in pressure on the fluid inside the device and in the sea, which causes water to rise through the pipe. As water rises (lift) due to a decrease in pressure, gas evolution from the water increases. Upon reaching the surface, the gas is collected for processing and the degassed water returns to the sea.

The drawing shows the proposed device.

The device has a pipe 1, provided in the lower part with a water intake in the form of a confuser, 2, of which a cylindrical electrode 3 is connected, connected to the positive pole of a constant source (anode). Inside volume, obg X

according to

"at

An acid-alkali resistant semi-permeable partition 4, which has the form, for example, of a cylinder closed by a fairing 5 and open from the bottom. Inside the volume of the cylinder formed by the partition 4, an electrode 6 is mounted, which is connected to a negative direct current source (cathode). Partition 4 divides the volume of water intake into two chambers: cathode and anode, the ratio of which is not less than 1:10. To prevent foreign objects from entering, the device is spooled with a metal grid 7 connected to an end part of the anode and a funnel-shaped visor 8 and separating the anode chamber from the open bottom end of the partition 4. The fairing 5 is attached to the confuser by means of ribs 9. The fairing has a hole 10 closed by a valve 11 installed on the float 12. The device may be equipped with an additional pipe (not shown) to discharge waste water.

The proposed device works as follows.

After reaching a predetermined depth and filling the device with sea water, the float 12, under the action of the Archimedean force, closes the valve 11 with the opening 10. A constant electric voltage is applied to the electrodes so that the current density on the electrodes does not exceed (0.5-1.0) A / cm2, while in the region of the anode an acidic medium begins to form, and at the cathode an alkaline medium. The mixing of these solutions, and hence their neutralization, is prevented by a tarpaulin partition. Thus, a highly acidic medium is created in the anode chamber. It is known that the pH of sea water at depths of the order of 1500-2000 m is equal to 7.8, which indicates a slightly alkaline reaction of the solution and the corresponding amount of hydrogen sulfide dissolved in water. Shifting the pH towards an increase in acidity leads to a decrease in solubility and the need to release both free and and bound hydrogen sulfide. The released gas passes through the confuser 2, enters the pipe 1 and causes the gas mixture to lift, since its specific gravity

less than sea water. In the process of raising the gas mixture, due to a decrease in pressure, hydrogen sulphide is further released, which creates additional lifting force. The gas duct enters the mixture on board the mining vessel, where hydrogen sulphide is released and collected for further processing directly on board or transported to shore. Spent water returns back to the hydrogen sulphide zone to depths of the order of 150-200 m. In addition to hydrogen sulfide, chlorine, carbon dioxide, etc. are released in the form of bubbles of gas at the anode.

facilitating lift and hydrogen at the cathode, which begins to collect under the cap formed by the semipermeable partition 4 and the fairing 5. As the hydrogen accumulates in the specified volume, water is squeezed out from there, which leads to a gradual decrease in the Archimedean force of the float 12, lowering the valve 11 and opening holes 10 through which periodic

Bleeding of hydrogen accumulated in the cathode chamber, which contributes to an increase in the gas volume of the water-gas medium in the pipe 1 and, consequently, improves the lift-and-rot conditions.

Tests carried out on the model of the device showed that, upon acidification, an intense release of hydrogen sulfide was observed. Upon acidification to pH 4.5, 99.5% of hydrogen sulfide is released into the free

condition of total content in sea water.

Claims (1)

Device for desorption of seawater containing hydrogen sulfide, including a pipeline with a cylindrical confuser located at the bottom, characterized in that, in order to increase the degree of desorption dissolved gases, the confuser is connected to the positive pole of the current source, and a cylindrical bushing is installed inside the confuser, connected to the negative pole of the current source and a diaphragm separated from the confuser, in the upper part of which a valve for gas outlet is placed.