There is a problem with aluminum electrolysis
The actual operating index is poor. Due to the short development time, the deep development of China's large-scale aluminum electrolysis cell in the production field is obviously insufficient, resulting in a large gap between the production indicators of actual operation indicators and the international advanced level. Most of them operate under heavy load and small grid environment, and there are many security risks. Aluminum and electric joint ventures are one of the trends in the development of China's electrolytic aluminum enterprises, but at the same time there are corresponding problems in technology. Due to the large scale of large-capacity electrolyzers (a series of production capacity can reach more than 200,000 tons), huge power load is concentrated in one production series (generally up to 400,000 KW), and any fluctuation in electrolytic series production will result in Large impacts of power grids or captive power plants, even threatening power supply security.
There is a lack of comprehensive design measures based on the "fine design" technology and the improvement of the life of the tank based on the mechanism and regularity of the cathode damage. The electrolytic cell is difficult to achieve the design life and the early damage rate is high. Problems affecting the life of large tanks in China In addition to the general reasons for the quality of cathode carbon materials in China, there are some problems in the design of electrolytic cells, furnace materials, furnace quality, roasting start, normal production operations and production management. . The underlying cause of these problems is that China still lacks an in-depth understanding of the mechanism and laws of aluminum cell damage (often referred to as cathode damage) and the "fine design" technology and comprehensive technical measures to improve the life of the tank. As the capacity of the electrolytic cell continues to expand, the problem of the life of the tank becomes more prominent.
Lack of advanced production and operation technology, high operating costs. China's 300KA-class extra large pre-baked aluminum electrolyzers have been put into industrial applications for a short period of time. It is also impossible to fully copy the previous experience on large prebaked tanks (these experiences are also very limited). The problem of uneven current distribution during the roasting start-up process is more prominent and the energy consumption during the roasting start-up process is large; the physical field (electric field, magnetic field, flow field) of the electrolyzer is easy to fluctuate after the operation, and the heat balance is difficult to maintain; It is vulnerable to external disturbances and fluctuates. It is difficult to extinguish after the anode effect occurs. Because of the large inertia of the electrolytic cell, it is difficult to quickly return to normal once the groove condition fluctuates or the groove condition is abnormal.
The new steel shell aluminum core anode claw for electrolytic aluminum is about 15% lower than the international advanced level in terms of the overall production status of China's electrolytic aluminum. The main performance is: current efficiency difference of 2-3 percentage points; The consumption difference is 300-800Kwh; the energy consumption of the anode for electrolytic aluminum is about 3Gj/t; the anode consumption of electrolytic aluminum is 30-60Kg (about 75-150Kg of standard coal); the life of the trough is about 1000 days; the anode effect coefficient The international advanced is 0.1 times/day. Below the trough, the best level in China is around 0.3 times/day.
Set screw is also called head screw and positioning screw. The utility model is a screw specially used for fixing the relative position of machine parts. Type: square flange end set Bolt, GB / t821-1988 square chamfered end set screw, GB / t85-1988 square long cylindrical end set screw, inner square head set screw, etc.
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Hexagon socket set screw, hexagon flat set screw, hexagon cylindrical set screw.
The selection of common set Screws is generally used to fix the relative position of two parts with little force. The axial and circumferential positioning of common sleeve like parts on the shaft. There are many kinds of set screws. The common ones are as follows: according to the end part, there are conical end, flat end, concave end, oblong cylinder head, etc;
According to the head part: slotted, hexagon socket, square head, etc. Tapered end screws and concave end screws with sharp ends can be used to directly top the parts, and the concave end is more reliable and can bear greater force; Taper end screws without sharp points must be drilled in the parts. The flat end is used to top the tight plane, which does not damage the parts, but bears limited load.
Slotted screws have small tightening force and are often easy to screw off. Generally, they prefer hexagon socket head; The tightening force of square head is the largest, but it can not be embedded in parts, and its use is limited. In order to prevent loosening and withdrawal of threaded parts, a set screw can be drilled at the cross seam. The long cylindrical head screw at the top end is used in the keyway of the shaft to lock and prevent circumferential rotation. It can also be used in general unimportant occasions when the key slides in the keyway of the shaft.
Set Screws,Allen Nose Set Screw,Slotted Head Set Screw,Hexagon Socket Grub Screw
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