1.Brief description
The activated carbon heating regeneration method is the most widely used and oldest regeneration method. The heating regeneration process utilizes the characteristic that the adsorbate in the adsorbed saturated activated carbon can be desorbed from the activated carbon pores at high temperature, so that the adsorbate is desorbed at high temperature, thereby opening the originally blocked gaps of the activated carbon and restoring its adsorption performance. After applying high temperature, the molecular vibration energy is enhanced, changing its adsorption equilibrium relationship, so that the adsorbate molecules are separated from the surface of the activated carbon and enter the gas phase. Heating regeneration has universality and thorough regeneration because it can decompose a variety of adsorbates. It has always been the mainstream of regeneration methods. Heating regeneration has the advantages of high regeneration rate and short regeneration time.
2.Principle of activated carbon regeneration furnace
This equipment adopts external heating. The entire regeneration system mainly consists of a control system, a special heat-resistant stainless steel cylinder, a furnace body, a feeding and discharging device, a mechanical transmission part and a heat preservation part. The rotary furnace regenerates activated carbon. The mechanical failure of the furnace body during the rotation process is very rare, and the operation and management work is relatively simple. Its characteristics are: large processing capacity, high degree of automation, continuous feeding and discharging, uniform and stable quality of regenerated products, easy operation and control, strong adaptability to materials, and low equipment failure.
3. Composition of stainless steel activated carbon regeneration furnace
The activated carbon regeneration rotary furnace is a cylindrical industrial furnace with a cylinder made of heat-resistant stainless steel or heat-resistant alloy. The furnace body is equipped with two rollers and a gear ring. The entire furnace body is supported by two sets of high-strength supporting wheels and driven by a motor reducer. The meshing between the gears drives the entire furnace body to rotate at a uniform and stable speed, so that the material layer and the activated gas in the furnace are constantly updated. The contact surface ensures uniform activation reaction. Electric heating, oil heating or coal heating devices, as well as water vapor inlets, temperature measuring holes, pressure measuring holes, observation holes and entry holes are installed as needed for easy operation and maintenance. There is a feeding device and a flue gas outlet at one end of the furnace, and an activated carbon product outlet and a cooling device are provided at the other end.
4. Operation process of activated carbon regeneration furnace
When the regeneration rotary furnace is working, the material is added to the furnace top hopper and is quantitatively and continuously fed into the furnace by the feeding device. Driven by the motor reducer, the uniform meshing of the gears causes the material layer on the furnace bed to be constantly turned over, the temperature of the material is constantly rising, and it is constantly moving forward under the push of the furnace spiral, and finally discharged from the discharge port. The temperature of each section can be adjusted by starting the number of combustion nozzles and their combustion intensity. The water vapor introduced from the water vapor inlet moves in a direction completely opposite to the material, and contacts with the material in countercurrent for activation; and finally discharged from the flue gas outlet on the top of the furnace and can preheat the wet carbon. The residence time (regeneration time) of the activated carbon in the furnace is controlled by the frequency converter to adjust the speed of the motor.
In order to achieve efficient and reliable regeneration of activated carbon, our company uses the latest technology to carefully design and manufacture the activated carbon activation and regeneration rotary furnace. This furnace has demonstrated production performance in the activated carbon regeneration furnace industry worldwide. The diameter and length of the furnace have been optimized to achieve different specific functions in independent partitions.
1. Drying zone, equipped with lifters, with sufficient residence time to effectively remove entrained water from the activated carbon;
2. Organic volatilization zone, to remove organic contaminants;
3. Regeneration zone, to reactivate the carbon;
4. Cooling zone, to reduce the temperature of the discharged carbon before water quenching.
All these zones are designed to ensure that each step of the carbon regeneration process, from feed to discharge, is given sufficient residence time to minimize carbon bed thickness and maximize mixing through the use of lifters to ensure maximum efficiency of regeneration.
For example, if the drying zone is too short or inefficient, so that the carbon still contains entrained water entering the activation zone, the rapidly vaporizing entrained water will cause cracking and internal cracks in the carbon. These weaknesses lead to increased wear of the activated carbon and the production of pulverized carbon, thereby increasing carbon losses. The main problem is that the fractured carbon will not be screened out and in its fragile state can become pulverized carbon during the CIP process. This will lead to increased gold loss with the activated carbon, which can be a significant source of gold loss in any gold extraction plant.
The diameter of the kiln is also optimized to ensure minimum carbon depth and maximum carbon-to-kiln shell contact. It also ensures that the riser achieves effective waterfall formation and improves contact of the carbon with the countercurrent gas phase. These can lead to significantly improved performance of the regeneration process.
The countercurrent gas phase is rich in steam, which is generated by water through nozzles installed at the discharge end. This steam helps to cool the carbon and plays an important key role in the activation process. This is because the steam can both activate the carbon and break down large organic molecules into smaller volatiles. The activated carbon regeneration kiln without steam injection is far from optimal activation conditions.
The efficient design of the activated carbon activation regeneration rotary kiln can reduce the loss of activated carbon, reduce the loss of gold-carrying fine carbon, and improve the activity of the activated carbon, thereby improving the gold recovery rate in the CIP process and reducing operating costs.
The key to successful activated carbon regeneration also comes from a thorough understanding of the material handling plant. The correct design for a standard CIP plant may not be ideal for the activated carbon used in the flotation plant. From the typical carbon activity diagram given, it can be seen that the correct kiln design, maximizing the steam partial pressure, maintaining the correct temperature, and designing the appropriate residence time can significantly improve the relative activity of the carbon.
In the flotation plant, the use of xanthogenic acid and frothers will cause contamination of the activated carbon used in the next CIP process. Therefore, in this case, the regeneration of activated carbon requires more active regeneration conditions, higher temperature and steam partial pressure to eliminate the flotation reagents. Careful design and optimization of temperature, steam partial pressure and residence time can effectively remove both frothers and collectors, along with other pollutants. The efficient design of our activated carbon activation and regeneration rotary kiln can reduce the loss of activated carbon, reduce the loss of gold-carrying powdered carbon, and improve the activity of activated carbon, thereby increasing the gold recovery rate in the CIP process and reducing operating costs.
The activated carbon activation and regeneration rotary kiln includes a complete system for process control, including a standard PLC and a color operator interface to control the burner, variable speed feeder and drum motor.
Main features:
Processing capacity: 1-15 tons per day;
Heating method: electric heating, liquefied natural gas, fuel oil;
Complete set: including feed hopper, dehydration feeder, control system, water quenching tank, etc.;
Easy to install: the whole set of equipment is placed on the horizontal concrete floor;
Quality assurance: strict testing before leaving the factory;
Sealing performance: good sealing performance, the replacement cycle of sealing materials is more than one year;
Carbon loss: minimum burning loss;
Temperature range: 700 – 950 C
Cylinder life: made of high-quality long-life alloy tubes;
Steam supply: either the activated carbon with its own moisture or the steam generator can be used, and the two methods have their own characteristics.
Furnace drum material: Under normal operating conditions, the alloy steel we choose is the material of the activated carbon regeneration kiln, which can provide corrosion resistance and meet the high temperature conditions and activation atmosphere of activated carbon regeneration.
