RU2187585C1 - Way of power supply to series of electrolyzers - Google Patents

Abstract

FIELD: electrical metallurgy, winning of aluminum in series of electrolyzers connected in series. SUBSTANCE: invention is meant for development of simple and economical way of power supply to series of electrolyzers which provides for rise of strength of current by required value across one or several individual electrolyzers of series. Power to electrolyzers is supplied from converter substation incorporating series of rectifiers connected in parallel. To rise strength of current across one or several individual busconnected electrolyzers of series one rectifier is placed in front of one or several electrolyzers across which strength of current should be raised from initial value and which voltage required for above-mentioned rise of strength of current is set. In this case voltage across the rest of rectifiers should be raised at same time to secure invariable magnitude of initial value of strength of current in series of electrolyzers. EFFECT: development of simple and economical way of power supply to series of electrolyzers. 1 dwg

Description

 The invention relates to electrometallurgy and can be used in the production of aluminum in series of series-connected electrolyzers.

 In aluminum production plants, electrolyzers are placed in housings and connected together in series in an electrolysis series, powered by direct electric current (50,000-200,000 A) from one common current source (converter substation). A series is usually supplied with current by a group of several parallel-connected converter units (rectifiers). The number of units in the group is determined by the current strength that you need to have on the series. Since the electrolyzers of the series are connected in series, the current strength on each of them is the same. In the series, so-called cases can be distinguished - groups of electrolyzers with their equal number. Usually in a series there are two cases.

 With the modernization of Soderberg electrolyzers with the increase in the area of the anodes, with the commissioning of electrolyzers with baked anodes, it becomes necessary to increase the current strength by one electrolyzer or a group of electrolyzers in one technological line of the casing.

 A known method of supplying electric current to several series of aluminum electrolysis cells, comprising supplying current to each series from an autonomous converter substation, in which additional electric current is supplied to electrolysis cells of one series by supplying electric current to them from a converter substation supplying electrolysis cells of another series (via an additional busbar), while at the last substation, respectively, increase the voltage (description to ed. certificate. 514918, IPC S 25 C 3/16, publ. 25.05.76. BI 19).

 The known method does not allow you to adjust the magnitude of the recharge current and, therefore, does not make it possible to increase the current strength by the required amount. In addition, the cost-effectiveness of the method is adversely affected by the excessive costs of the busbar trunking, as well as the high labor costs associated with regulating the voltage at the converter substation.

 A known method of supplying a series of electrolytic cells connected by buses, including supplying current to the electrolysis series from a converter substation, containing a series of rectifiers connected in parallel, in which, for additional recharge by electric current of one or more electrolytic cells in a series, current is supplied to them from an additional recharge unit , which is connected in parallel to those electrolyzers on which it is necessary to increase the current strength (the installation is described in the USSR author's certificate 514918, Olonka 1, pp. 8-19).

 The disadvantages of this method include its low cost associated with high capital costs required for the construction of a special conversion substation, as well as additional losses of electricity for conversion and excessive operating costs for maintenance.

 The claimed invention is directed to the development of a simple and economical method of supplying current to a series of electrolyzers, which makes it possible to increase the current strength by the required amount on one or more separate series electrolyzers.

 The technical result noted above is achieved by a method of supplying current to a series of electrolyzers connected by buses, including supplying current to the electrolysis series from a converter substation containing a series of rectifiers connected in parallel, in which one of the rectifiers is connected directly in front of one or more electrolyzers, on which it is necessary to increase the power current from its initial value, and set the voltage required for the aforementioned increase in current strength, while simultaneously the voltage on the remaining rectifiers is increased to ensure a constant value of the initial current strength in the electrolysis series.

 The essence of the claimed invention is as follows.

 Studies have shown that the feeding of individual electrolyzers or groups of electrolyzers can be done by connecting one of the rectifiers of the converter substation directly in front of these electrolyzers and setting the voltage on it to provide the required amount of recharge current, while increasing the voltage on the remaining rectifiers to ensure a constant value of the initial value of the force current in the electrolysis series. The experiments confirmed that the developed method allows, firstly, to increase the current strength on a specific electrolyzer (group of electrolyzers) by a predetermined amount and, secondly, to significantly reduce both operational and energy costs for implementing the method.

The method can be illustrated by the drawing, which depicts electrolyzers (1. ..- 1 _nk ...- 1 _n ), placed respectively in the first (2) and second (3) buildings and combined in an electrolysis series. The electric current is supplied to the series from a converter substation (4) containing rectifier units connected in parallel (5).

 The method is as follows.

 To increase the current strength on the electrolyzers placed in the second case, the positive pole of one of the rectifiers, for example (5a), is connected in front of the indicated electrolyzers (at point A). On the specified rectifier (5A) using a transformer (not shown) set the voltage that provides the specified charging current. At the same time, the voltage at all rectifiers is also increased at the converter substation (4) in order to ensure a constant value of the initial current strength in the electrolysis series.

If it is necessary to increase the current strength on several electrolyzers placed in the housing, for example, on electrolyzers 1 _nk -1 _n , the positive pole of the selected rectifier (5a) is connected at point B, that is, immediately before the indicated electrolyzers.

 The following is an example confirming the possibility of implementing the claimed invention to obtain the above technical result.

 Example.

 The inventive method was used at the Kandalaksha aluminum plant with an increase in current strength of 3 kA on electrolyzers placed in the second case of the electrolysis series, the power supply circuit of which is shown in the drawing.

 Electric current was supplied to the series from a silicon-transforming substation (CAT) containing ten rectifier units connected in parallel to each other. The current in the series was 75 kA.

To increase the current strength by 3 kA on electrolyzers (1-1 _n ), a separate rectifier unit was allocated at the gearbox. In the 800 V DC switchgear (RU-800) of the gearbox, the DC disconnectors of the selected unit on the minus were left connected to the RU-800 bus system, and the disconnectors on the plus were disconnected from the RU-800 bus system. From the “plus” disconnectors of the unit to node A, an energizing busbar made of an aluminum bus bar with a section of 250x29 mm on a steel rack 7 m high was laid on the inter-busbar bridge at the second building. The voltage of the series is 740 V, the voltage on the second case is 370 V. Thus, the feed unit must supply to the second building, taking into account losses in the circuit elements, a current of 3 kA at a voltage of 370 V. To do this, on the primary side of the 10KV feed aggregate transformer TDNP-25000/10 range switch (switching without heating narrow) is set to the 2nd range, and the switch under the load of the on-load tap-changer is 4-7 steps so that the voltage on the rectifier provides a feed current of 3 kA. The voltage on the remaining rectifiers is regulated in a similar way to ensure a constant current strength (75 kA) in the electrolysis series.

 Thus, the claimed invention successfully solves the problem of creating a simple and economical method of supplying current to a series of electrolyzers, allowing at minimum cost to carry out the work of the required number of electrolyzers of the series with increased current strength.

Claims (1)

 A method of supplying current to a series of electrolyzers connected by buses, including supplying current to the electrolysis series from a converter substation containing a series of rectifiers connected in parallel, characterized in that one of the rectifiers is connected directly in front of one or more electrolyzers, on which it is necessary to increase the current strength from it the initial value, and set the voltage necessary for the aforementioned increase in current, while simultaneously increasing the voltage on the other, straighten s to ensure the constant value of the initial value of the current in the electrolysis series.