阅读说明：本技术 一种铝电解槽炉底外部保温与节能降耗的方法 (Method for external heat preservation and energy saving and consumption reduction of aluminum cell furnace bottom ) 是由 成庚 刘海锋 刘进县 杨成亮 杨国伟 金占雄 张鸿翎 魏福吉 刘俊英 郭文善 陈 于 2021-10-13 设计创作，主要内容包括：本发明涉及铝电解行业技术装备和节能降耗技术领域,具体涉及一种铝电解槽炉底外部保温与节能降耗的方法。本发明专利的保温材料添加在现有设计、安装和生产的有底电解槽底部外面,按需帮助解决电解槽在形成和维持电解槽炉帮厚度和伸腿长度以及节能降电压过程中炉底变冷问题,使电解质初晶温度等温线可持续维持在阴极炭块下面,实现电解生产过程稳定优化运行而适当降低槽电压,进一步实现节能降耗。(The invention relates to the technical field of technical equipment and energy conservation and consumption reduction in the aluminum electrolysis industry, in particular to a method for preserving heat and saving energy consumption at the outer part of a furnace bottom of an aluminum electrolysis cell. The heat insulating material is added outside the bottom of the electrolytic cell with a bottom designed, installed and produced in the prior art, helps to solve the problems that the electrolytic cell forms and maintains the thickness of the furnace wall and the length of the extending leg of the electrolytic cell and the furnace bottom becomes cold in the process of energy conservation and voltage reduction as required, so that the temperature isotherm of the primary crystal temperature of the electrolyte can be continuously maintained below the cathode carbon block, the stable and optimized operation of the electrolytic production process is realized, the cell voltage is properly reduced, and the energy conservation and consumption reduction are further realized.)

1. A method for external heat preservation and energy conservation and consumption reduction of an aluminum cell furnace bottom is characterized by comprising the following steps:

s1, additionally arranging a heat-insulating material layer (2) outside the bottom of the electrolytic cell, wherein the heat-insulating material layer (2) is a calcium silicate board or a ceramic fiberboard;

s2, the thickness of the furnace side of the electrolytic cell is 10-20 cm, the length of the extending leg is 5-18 cm, and the voltage drop of the furnace bottom of the aluminum electrolytic cell is 180-390 mV;

s3, installing a temperature measuring probe on the electrolytic cell, and respectively monitoring the bottom of the aluminum electrolytic cell, the cradle frame and the cathode steel bar;

s4, gradually and stably reducing the voltage drop of the aluminum electrolytic cell, keeping the temperature of a cathode steel bar at 260-310 ℃, the temperature of a furnace bottom at 80-230 ℃, and keeping the primary crystal temperature of electrolyte at 925-935 ℃; the isotherm is located at the lower part of the cathode carbon block.

2. The method for external heat preservation and energy conservation and consumption reduction of the aluminum cell bottom according to claim 1, wherein in the step S2, the voltage drop of the aluminum cell bottom is set according to different materials of the aluminum cell, wherein the voltage drop of the fully graphitized cathode is 220-280 mV, the voltage drop of the poured fully graphitized cathode is 180-220 mV, and the voltage drop of the high graphite cathode is 330-390 mV.

3. The method for preserving heat at the outside of the bottom of an aluminum electrolytic cell, saving energy and reducing consumption as claimed in claim 1, wherein the heat-preserving material layer (2) in the step S1 is laid on the upper part of the lower edge of the cell bottom I-shaped steel (1) of the cradle frame at the bottom of the aluminum electrolytic cell.

4. The method for preserving heat, saving energy and reducing consumption of the outside of the bottom of the aluminum electrolytic cell according to claim 3, wherein the thickness of the heat-preserving material layer (2) in the step S1 is 10-80 mm, and the number of paving layers is at least one.

5. The method for preserving heat outside the bottom of an aluminum electrolysis cell as claimed in claim 3, wherein the heat-preserving material layer (2) in step S1 is attached to the bottom of the aluminum electrolysis cell or has a gap.

6. The method for preserving heat at the outside of the bottom of an aluminum electrolysis cell as claimed in claim 5, wherein in step S4, when a gap is left between the heat preservation material layer (2) and the bottom of the aluminum electrolysis cell, the cell voltage is reduced by 18-22 mV; when the heat insulating material layer (2) is attached to the bottom of the aluminum electrolytic cell, the cell voltage is reduced by 26-30 mV.

7. The method for preserving heat at the outside of the bottom of the aluminum electrolytic cell, saving energy and reducing consumption of the claim 6, wherein in the step S4, when a gap is left between the heat preservation material layer (2) and the bottom of the aluminum electrolytic cell, the heat preservation material layer (2) is used for plugging the end heads at the two sides of the I-shaped steel (1) at the bottom of the cell in the length direction to form a closed heat preservation cavity, and the voltage of the cell is reduced by 22-26 mV.

Technical Field

The invention relates to the technical field of technical equipment and energy conservation and consumption reduction in the aluminum electrolysis industry, in particular to a method for preserving heat and saving energy consumption at the outer part of a furnace bottom of an aluminum electrolysis cell.

Background

The energy utilization rate of the aluminum electrolysis cell in the production process is about 50%, as shown in fig. 1, about half of the energy is dissipated in the atmosphere in the form of heat, which not only causes a great deal of energy waste, but also causes the ambient temperature around the aluminum electrolysis cell to rise, thereby affecting the heat balance of the aluminum electrolysis cell, being one of the important heat sources causing the high-temperature operation of aluminum electrolysis, and the energy conservation and emission reduction are still the core key technology research and development field in the future of aluminum electrolysis. As illustrated by the prior art example, the bottom heat removal of the cell represents about 7% of the total heat removal, about 3.5% of the energy consumption of the electrolytic aluminum, corresponding to an energy consumption per ton of aluminum of about 450 kWh/t.Al.

Disclosure of Invention

The invention aims to solve the problem of energy conservation and heat preservation outside the bottom of an electrolytic cell in the prior art, and provides a method for heat preservation outside the bottom of an aluminum electrolytic cell, energy conservation and consumption reduction.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a method for external heat preservation and energy conservation and consumption reduction of the bottom of an aluminum electrolytic cell comprises the steps of arranging heat preservation materials such as ceramic fiber boards on the lower edge of I-shaped steel on the outer side of the bottom of an electrolytic cell shell, reducing cell voltage on the basis of maintaining energy balance, keeping furnace side thickness and extension leg length and optimizing design principles, and achieving energy conservation and consumption reduction.

A method for external heat preservation and energy conservation and consumption reduction of an aluminum cell furnace bottom comprises the following steps:

s1, additionally arranging a heat-insulating material layer outside the bottom of the electrolytic cell, wherein the heat-insulating material layer is a calcium silicate board or a ceramic fiberboard;

s2, the thickness of the furnace side of the electrolytic cell is 10-20 cm, the length of the extending leg is 5-18 cm, and the voltage drop of the furnace bottom of the aluminum electrolytic cell is 180-390 mV;

s3, installing a temperature measuring probe on the electrolytic cell, and respectively monitoring the bottom of the aluminum electrolytic cell, the cradle frame and the cathode steel bar;

s4, gradually and stably reducing the voltage drop of the aluminum electrolytic cell, keeping the temperature of a cathode steel bar at 260-310 ℃, the temperature of a furnace bottom at 80-230 ℃, and keeping the primary crystal temperature of electrolyte at 925-935 ℃; the isotherm is located at the lower part of the cathode carbon block.

In the step S2, the voltage drop of the aluminum cell bottom is set according to different materials of the aluminum cell, wherein the voltage drop of the fully graphitized cathode is 220-280 mV, the voltage drop of the poured fully graphitized cathode is 180-220 mV, and the voltage drop of the high graphite cathode is 330-390 mV.

And in the step S1, the heat-insulating material layer is laid on the upper part of the lower edge of the trough bottom I-shaped steel of the cradle frame at the bottom of the electrolytic trough.

In the step S1, the thickness of the heat-insulating material layer is 10-80 mm, and the number of the paving layers is at least one.

In the step S1, the heat-insulating material layer is attached to the bottom of the aluminum electrolysis cell or a gap is left between the heat-insulating material layer and the bottom of the aluminum electrolysis cell.

In the step S4, when a gap is left between the heat insulation material layer and the bottom of the aluminum electrolysis cell, the cell voltage is reduced by 18-22 mV; when the heat insulation material layer is attached to the bottom of the aluminum electrolysis cell, the cell voltage is reduced by 26-30 mV.

And in the step S4, when a gap is reserved between the heat insulation material layer and the bottom of the aluminum electrolysis cell, the heat insulation material layer is used for plugging the end heads at the two sides of the length direction of the I-shaped steel at the bottom of the cell to form a closed heat insulation cavity, and the voltage of the cell is reduced by 22-26 mV.

Compared with the prior art, the invention has the following beneficial effects:

the heat insulation material disclosed by the invention is added outside the bottom of the electrolytic cell with a bottom designed, installed and produced in the prior art, and can help solve the problems that the electrolytic cell forms and maintains the thickness of the furnace wall and the length of the extending leg of the electrolytic cell and the furnace bottom becomes cold (the primary crystal temperature isotherm moves upwards) in the energy-saving voltage reduction process as required, so that the electrolyte primary crystal temperature isotherm can be continuously maintained below the cathode carbon block, the stable and optimized operation of the electrolytic production process is realized, the cell voltage is properly reduced, and the energy saving and consumption reduction are further realized.

The invention can keep good heat balance and electric balance, the inner isotherms are continuously and reasonably distributed, the stable production of the electrolytic cell is ensured, the power consumption is reduced, the side lining is well protected, and the service life of the electrolytic cell is prolonged. The invention adopts the heat insulation structure with better heat insulation performance at the outer side of the bottom of the tank, and has the following advantages:

the electrolytic cell disclosed by the invention is provided with a plurality of groups of temperature measuring probes for multipoint temperature monitoring, the temperatures below the cathode steel bar and the bottom of the electrolytic cell are kept unchanged basically through reasonable optimization and coupling balance of a technical condition system such as cell voltage and the like, and the isothermal line of the primary crystal temperature of the electrolyte is kept below the cathode carbon block, so that the continuous monitoring of the isothermal line of the primary crystal temperature is realized.

According to the invention, the calcium silicate board or the ceramic fiber board is used as the heat insulation layer, and the waste calcium silicate board or the ceramic fiber board can be selected for secondary recycling, so that the heat insulation is carried out on the outer side of the bottom of the electrolytic cell, the heat insulation material cost is saved, the waste material recycling is fully carried out, and the environment-friendly, cost-reducing and efficiency-improving effects are facilitated.

The invention adopts the heat insulation material to be placed on the lower edge of the I-steel of the cradle frame at the bottom of the electrolytic tank, the cradle frame is supported or covered according to the size and the hardness of a calcium silicate board or a ceramic fiber board, and the layout of the heat insulation material is adjusted according to the actual requirement of the heat insulation degree, so that the optimal heat insulation effect is formed. On the basis of stably and reasonably keeping the thickness of the furnace wall of the electrolytic cell, the length of the extending leg and the voltage drop of the furnace bottom, the invention gradually and stably reduces the cell voltage, realizes energy conservation and consumption reduction, can also be used for newly building a bottomed or bottomless electrolytic cell designed, installed and produced, adopts a refractory heat-insulating lining material resistant to electrolyte corrosion, continuously keeps the thickness of the furnace wall and the length of the extending leg, carries out various forms of heat-insulating measures such as the lower edge of I-steel at the bottom of the bottomed cell, the bottom surface of a cell shell and the like or environmental-friendly and standard-reaching heat-insulating measures for the bottomless cell, and allows the primary crystal temperature isotherm of the electrolyte to move downwards from the lower surface of a cathode carbon block.

Drawings

FIG. 1 is a schematic diagram of a prior art structure;

FIG. 2 is a schematic structural view of the present invention;

fig. 3 is a sectional view taken along line a-a of fig. 2.

In the figure: 1. the groove bottom is made of I-shaped steel; 2. a thermal insulation material layer; 3. a cathode carbon block group; 4. cathode lining fireproof heat-insulating layer

5. A cathode steel bar temperature measuring probe I; 6. A cathode steel bar temperature measuring probe II; 7. a cathode steel bar; 8. a furnace bottom temperature measuring probe.

Detailed Description

The invention provides a method for preserving heat and saving energy and reducing consumption of the outside of the bottom of an aluminum electrolytic cell, which is characterized in that the bottom I-shaped steel 1 is arranged at the bottom of the aluminum electrolytic cell in the existing equipment, and a cathode carbon block group 3, a cathode lining fireproof heat preservation layer 4 and a cathode steel bar 7 are arranged in the aluminum electrolytic cell, and the method comprises the following steps:

s1, additionally arranging a heat insulation material layer 2 outside the bottom of the electrolytic cell, wherein the heat insulation material layer 2 is a calcium silicate board or a ceramic fiberboard;

s2, the thickness of the furnace side of the electrolytic cell is 10-20 cm, the length of a leg (excluding an artificial leg) is 5-18 cm, and the voltage drop of the furnace bottom of the aluminum electrolytic cell is 180-390 mV;

s3, installing a temperature measuring probe on the electrolytic cell, and respectively monitoring the bottom of the aluminum electrolytic cell, the cradle frame and the cathode steel bar; wherein, both ends of the cathode steel bar 7 are respectively provided with a cathode steel bar temperature probe I5 and a cathode steel bar temperature probe II 6, the bottom of the aluminum electrolysis cell is provided with a furnace bottom temperature probe 8, and the bottom of the aluminum electrolysis cell and the cradle frame are additionally provided with the number of temperature probes according to the temperature monitoring requirement to ensure that the test is accurate and timely;

s4, gradually and stably reducing the voltage drop of the aluminum electrolytic cell, keeping the temperature of a cathode steel bar at 260-310 ℃, the temperature of a furnace bottom at 80-230 ℃, and keeping the primary crystal temperature of electrolyte at 925-935 ℃; the isotherm is located at the lower part of the cathode carbon block.

In the step S2, the voltage drop of the aluminum cell bottom is set according to different materials of the aluminum cell, wherein the voltage drop of the fully graphitized cathode is 220-280 mV, the voltage drop of the poured fully graphitized cathode is 180-220 mV, and the voltage drop of the high graphite cathode is 330-390 mV.

In the step S1, the heat insulation material layer 2 is laid on the upper part of the lower edge of the trough bottom I-shaped steel 1 of the cradle frame at the bottom of the electrolytic trough.

In the step S1, the thickness of the heat-insulating material layer 2 is 10-80 mm, and the number of the laying layers is at least one.

In the step S1, the heat insulating material layer 2 is attached to the bottom of the aluminum electrolytic cell or a gap is left between the heat insulating material layer and the bottom of the aluminum electrolytic cell. In the step S4, when a gap is left between the heat insulation material layer 2 and the bottom of the aluminum electrolysis cell, the cell voltage is reduced by 18-22 mV; when the heat insulating material layer 2 is attached to the bottom of the aluminum electrolysis cell, the cell voltage is reduced by 26-30 mV.

And in the step S4, when a gap is reserved between the heat insulation material layer 2 and the bottom of the aluminum electrolysis cell, the heat insulation material layer 2 is used for plugging the end heads at the two sides of the I-shaped steel 2 at the bottom of the cell in the length direction to form a closed heat insulation cavity, and the voltage of the cell is reduced by 22-26 mV.

The invention can use the heat exchange device at the outer side of the steel plate at the bottom of the electrolytic cell to maintain the design temperature of the steel plate at the bottom of the electrolytic cell, and can recycle the waste heat while maintaining the design temperature of the steel plate at the bottom of the electrolytic cell by using the heat exchange amount of the heat exchange device at the outer side of the steel plate at the bottom of the electrolytic cell.

When the method is used specifically, under the condition that the isothermal line of the primary crystal temperature of the electrolyte is maintained below the cathode carbon block on the bottom electrolytic cell designed, installed and produced in the prior art, the external heat preservation of the bottom of the electrolytic cell is properly enhanced, the energy balance of the anode region and the cathode region of the electrolytic cell is kept, and a certain cell voltage is reasonably reduced to realize energy conservation and consumption reduction. A plurality of temperature measuring probes are arranged on each electrolytic cell, 2 temperature measuring probes are respectively arranged in the middle of the bottom of the electrolytic cell, and 2 temperature measuring probes are arranged on a cradle frame of the electrolytic cell; two ends of the cathode steel bar are respectively 1; and carrying out multipoint temperature monitoring. The outside of the shell at the bottom of the electrolytic cell is insulated by using an insulating material layer, and the insulating material can be in contact with the shell or not. The thermal insulation performance of the thermal insulation material contacting the cell shell is superior to that of the cell shell without contacting, when the thermal insulation performance of the inner lining of the electrolytic cell is obviously insufficient, the inherent insufficiency of the thermal insulation performance caused by design or construction and the acquired insufficiency of the thermal insulation performance caused by the damage of the thermal insulation material in the use process are included, the thermal insulation mode that the thermal insulation material contacts the cell shell is preferentially adopted, the insufficiency of the thermal insulation performance of the inner lining material is made up, and the thermal insulation performance outside the cell shell is increased. The external heat-insulating material at the bottom of the electrolytic cell can utilize waste microporous calcium silicate boards or ceramic fiber boards and other related materials, the thickness of the heat-insulating material is 10-80 mm, the number of layers is one, the cost of the heat-insulating material can be saved, the waste can be recycled, precious storehouse space can be saved, and the environment-friendly, cost-reducing and efficiency-improving effects are facilitated. The heat insulation material can be placed on the lower edge of the I-steel of the cradle frame at the bottom of the electrolytic cell and can be supported or shed, the hard heat insulation material adopts a supported arrangement mode, and the soft heat insulation material adopts a shed arrangement mode. The arrangement mode is a conventional heat insulation material installation mode, and a closed space or an open space can be formed between the heat insulation material and the tank shell. The heat preservation performance of the closed space is superior to that of the open space, and when the heat preservation performance of the open space is insufficient, the heat preservation mode of the closed space is adopted. By reasonably optimizing a technical condition system such as bath voltage and the like and coupling balance, the temperature below a cathode steel bar is kept at 260-310 ℃ and the temperature at the bottom of a furnace is kept at 80-230 ℃, the primary crystal temperature of electrolyte is kept at 925-935 ℃, and an isothermal line is positioned below a cathode carbon block. On the basis of stably and reasonably keeping the thickness of the furnace side of the electrolytic cell to be 10-20 cm, the length of the extending leg (excluding the artificial extending leg) to be 5-18 cm, the voltage drop of the furnace bottom, the total graphitized cathode to be 220-280 mV, the poured total graphitized cathode to be 180-220 mV and the high graphite cathode to be 330-390 mV, the voltage of the electrolytic cell is gradually and stably reduced, and energy conservation and consumption reduction are realized.

In addition, a heat exchange device, such as a heat pipe exchanger, is used outside the steel plate at the bottom of the electrolytic cell to maintain the design temperature of the steel plate at the bottom of the cell to be 80-100 ℃. The heat exchange amount of the outer side of the steel plate at the bottom of the electrolytic cell is recovered while the design temperature of the steel plate at the bottom of the electrolytic cell is maintained by using the heat exchange device. On a bottom or non-bottom electrolytic cell designed, installed and produced in the future, a refractory heat-insulating lining material capable of resisting electrolyte corrosion is adopted, the thickness of a furnace side and the length of a leg extending are continuously maintained, various heat-insulating measures such as the lower edge of I-steel at the bottom of the bottom cell, the bottom surface of a cell shell and the like are carried out, or the environment-friendly heat-insulating measures reaching the standard for the non-bottom cell are carried out, and then an electrolyte primary crystal temperature isotherm is allowed to move downwards from the lower surface of a cathode carbon block.

In the normal production process, the bath voltage of the heat-preservation and energy-saving bath at the bottom of the furnace is reduced by more than 20mV compared with that of a contrast bath, energy is saved by more than 60kWh/t.Al per ton of aluminum, the heat balance state at the bottom of the furnace is further improved, the stability of the bath is correspondingly improved, and the service life of the bath is prolonged. The patent also supports the technology of bottom heat preservation, energy saving and consumption reduction of the furnace bottom with the bottom groove, which further enhances the bottom heat preservation of the bottom groove, intelligently controls the temperature of the bottom of the furnace by a heat exchange device, recovers the waste heat utilization and meets the requirement of environmental protection when the fireproof heat-insulating material of the bottom of the furnace has enough electrolyte resistance and corrosivity of aluminum.