2nd period, 1976 – 1985: development of flow-through electrochemical diaphragm reactors with coaxial electrodes

Installations with one rotating electrode (in the pictures on the left) and two (in the upper right) have been developed and tested in practical drilling conditions. The capacity of the plant is from 100,000 to 180,000 liters per hour. Due to the presence of a positive electrode with automatic removal of clay crust, the EATSO installations allowed for high-quality cleaning of drilling mud without the use of hydrocyclones and vibrating screens. Kokand region of Uzbekistan, 1978.

The development and creation of installations for unipolar electrochemical water treatment (hereinafter referred to as electrotreatment) began in 1975.

By 1976, the productivity of single installations for electric water treatment (UEV) with flat electrodes reached 20 cubic meters per hour (photo on the right). This made it possible to use them not only on drilling rigs, where activated water – catholyte – was used for the preparation of drilling fluids and cooling of diesel engines, but also in the processes of displacement of oil during circuit and in-circuit flooding. In the photo on the left – one of the PPD points at the Uzbekneft oil field, 1976.

Reactors of UEV installations with flat electrodes could not compete with coaxial reactors either in terms of performance, economy, or functional parameters of water (catholyte, anolyte). Already the first primitive designs of reactors with coaxial placement of electrodes – a rod anode, a canvas diaphragm (fire hose) and a tubular external cathode (photo on the right) showed that one reactor of this type operating at a voltage of 20 volts and a current of 500 amperes can provide a capacity of 5 cubic meters. per hour for both catholyte and anolyte, which was equal to the productivity of the UEV-10 installation (photo on the left), the reactor of which, with a total current of 800 amperes and a voltage of 36 volts, provided somewhat worse technological parameters of anolyte and catholyte. The reason for the differences is the “spotty” electrical conductivity, which is characteristic of all, without exception, reactors with flat electrodes operating on dilute water-salt solutions. The negative effect of “spotty” electrical conductivity is the higher, the lower the mineralization. Tashkent, SredAzNIIGaz, 1977.

The development and industrial testing of various reactor variants with coaxial placement of electrodes and diaphragm made it possible to determine the optimal ratio of the size and shape of the electrode chambers, to get closer to understanding the most important role of the physico-chemical, mechanical and filtration properties of the diaphragm. The diaphragms in the first versions of the reactors were made of tarpaulin (belting), however, with the accumulation of experience, the diaphragms became mechanically more rigid – from chloride on the frame to a special porous asbestos cement. Turkmenistan, Uzbekistan, 1977.

UEV-4 installation for obtaining electrochemically activated water used in the processes of preparation and processing of drilling mud, water treatment for cooling systems of gas treatment plants, compressor stations of main gas pipelines. Six hydraulically parallel connected flow-through electrochemical reactors with coaxial placement of electrodes and diaphragm. The anodes are graphite rods with a diameter of 100 mm and a length of 900 mm, the diaphragm is a chlorin fabric on a vinyl plastic frame. The interelectrode distance is 10 mm. The capacity for catholyte is 25,000 l/h, for anolyte – 5,000 l/ h, the current is 1,200 A, the voltage is 30 V. The Kokand plant “Bolshevik” produced more than a thousand such installations in the period from 1977 to 1980.

The UEV-4 units were used not only in the technological processes of drilling and oil and gas production, but also in the processes of gas transportation (cooling of the gas motor compressors of the Bukhara-Ural gas pipeline with softened water), for soaking cotton seeds before sowing (photo above), which allowed to increase yields by 15-20% due to the acceleration of germination, the destruction of diseases of cotton (wilt), stimulating the growth and development of plants. UEV – 4 installations were also used in the processes of underground coal gasification (g. Angren) for water purification from phenols and other toxic gasification products, in the system of scrubber cleaning of flue gases of steelmaking furnaces (Gorlovka), in the technology of protecting pipelines from corrosion when pumping chemically aggressive groundwater (Nizhnevartovskneftegaz), in the technology of uranium leaching by preparing a working solution of sulfuric acid with a concentration reduced by three times on anolyte formation water, which provided an increase in uranium extraction by 5-7% (Leninabad Mining and Chemical Plant). Uzbekistan, 1979.

Laboratory flow-through electrochemical reactors ELHA-035 (photo above) and FORK-03 (photo below left), equipped with electrodes made of graphite MPG-6 and separation diaphragms made of ultrafiltration fluoroplastic film with separators made of polyvinyl chloride mesh. The interelectrode distance is 3 mm, the capacity for anolyte and catholyte of fresh (up to 1 g / l) water is 15 liters per hour at a current of 3.5 amperes and a voltage of 30 volts. The WELKHA–03 reactor could operate not only on mineralized water, but also on distilled water, gasoline or oil. At the same time, the operating voltage on the electrodes ranged from 5 to 25 kilovolts at a current of 5 to 20 mA.
Such laboratory reactors were used to perform research work in various organizations. Tashkent, SredAzNIIGaz, 1979.

Laboratory electrochemical flow reactors with a coaxial diaphragm made of porous polyvinyl chloride and glass graphite electrodes (photo on the left). A flow-through electrochemical reactor with a coaxial diaphragm made of porous polypropylene for the production of electrochemically activated anolyte and catholyte of fresh water, dilute aqueous solutions of electrolytes. The anode of the reactor is a pyrographite rod with a diameter of 80 mm and a length of 300 mm, the cathode is stainless steel. The current is up to 60 A, the voltage is up to 170 V (photo at the top right).
Laboratory reactor for electrochemical treatment of distilled water in the duct (photo at the bottom right). Tashkent, SredAzNIIGaz, 1978.

Laboratory submersible electrochemical reactors for unipolar electrochemical treatment of liquids in tanks. The auxiliary electrode of these reactors, protected by a diaphragm, had its own electrolyte circulation circuit. Tashkent, 1978

1 – laboratory flow diaphragm electrochemical reactor (photo on the left) is the first in a series of reactors with a ceramic coaxially mounted diaphragm and a prototype of high–performance industrial reactors. The anode of the reactor is a pyrographite rod with a diameter of 80 mm and a length of 300 mm, the cathode is stainless steel, the diaphragm is alund ceramics. Current strength – up to 60 A, voltage – up to 170 V. Tashkent, SREDAZNIIGAZ, 1979. 2, 3 – ELHA-002 installation for obtaining anolyte and catholyte from tap (drinking) water. The cathode is a monoblock made of graphite with a diameter of 600 mm and a length of 1000 mm with seven longitudinal channels with a diameter of 120 mm for fixing diaphragms made of alund ceramics and graphite anodes coated with manganese dioxide placed inside each diaphragm. The capacity of the installation is 1000 liters per hour of catholyte and 600 liters per hour of anolyte. Current strength – up to 500 A, voltage – up to 170 V. Tashkent, Uzptitseprom, 1984.

Experimental installation for the study of the electrochemical process of natural gas purification from hydrogen sulfide at the Sarytash field. The installation was made by the employees of Sredazniigaz: laboratory for the introduction of electrochemical technology (head of the lab. Yu.Zadorozhny) and the Laboratory of Electrical Technology (head of the lab. V.Bakhir). The installation has demonstrated the ability to reduce the cost of cleaning low-sulfur natural gas from hydrogen sulfide by about five times compared to traditional technology (monoethanolamine method). Karshi region, 1983.

Experimental installation for the study of the electrochemical process of natural gas purification from hydrogen sulfide (the TASHKENT process) at the Mubarek gas sulfur plant. The installation was made by the employees of Sredazniigaz: laboratory for the introduction of electrochemical technology (head of the lab. Yu.Zadorozhny) and the Laboratory of Electrical Technology (head of the lab. V.Bakhir). The installation has demonstrated the ability to reduce the cost of purification of natural high-sulfur gas from hydrogen sulfide by approximately three times compared to traditional technology (monoethanolamine method). Karshinskaya region, 1984.

2nd period, 1976 – 1985: development of flow-through electrochemical diaphragm reactors with coaxial electrodes

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