Treatment methods for spent activated carbon

Biconical drying with solvent recovery – consult the manufacturer; it should be easy to resolve! Many years ago, the company took the filter residue to be dried in order to recover the filtrate contained within the filter cake – I have never seen the actual production process

It was rejected; it was said that dried activated carbon dust mixed with solvents can easily explode

After drying, it turns into dust – how could it mix with a solvent? There may be a little organic vapor in the system. Cool down the barrel with nitrogen, then open it to unload the contents! At that time, the company took the Grignard reagent filter cake to be dried; it is said that a fire broke out, but no significant damage was caused.

In fact, vacuum drying can be used; cone drying was tried first, but a large ball-shaped clump formed in the middle. Rotating-vane drying was planned as an alternative, and nitrogen was intended to be used to remove the vacuum, but dust along with residual organic solvents can easily lead to explosions. The plan was rejected! Now, a rough method similar to high-pressure oil extraction might be used to extract as much as possible, with the filter cake being treated as solid waste! I hope everyone can provide better methods!

If it were feasible or profitable, the boss would have done it already

Chlorine is a hassle. If it contains no chlorine, consider finding an activated carbon regeneration plant that has the qualifications for handling hazardous waste. But with chlorine present now, the gas emissions from the recycling plants will be affected, and there is also a risk of corrosion in the recycling furnaces; therefore, it is highly likely that they won’t accept it. If one is to use a thermal regeneration device, it is only economical when the annual processing capacity exceeds 500 tons.

Benzene chloride has a boiling point of 131.6°C; it is vaporized by heating and then recovered through condensation, and this physical process poses risks of fire and explosion. The cost of regenerating activated carbon is high, its capacity declines, making it uneconomical.

Steam regeneration, or adding water to the reactor and heating it for distillation

A technology that utilizes ultrasound to desorb activated carbon, which has been used to treat wastewater containing organic substances and heavy metal ions through filtration, once it reaches adsorption saturation; this is a technique for regenerating the activated carbon. As ultrasonic high-frequency sound waves propagate through a medium, they generate intense mechanical vibrations. These waves radiate forward in an alternating pattern within the cleaning medium, causing the liquid to move and creating tens of thousands of tiny bubbles. The tiny bubbles in the liquid (cavitation nuclei) vibrate vigorously under the influence of the sound field. When the sound pressure reaches a certain level, the bubbles expand rapidly before suddenly collapsing. When these bubbles collapse, shock waves are generated, creating pressures of several thousand atmospheres in their vicinity; this destroys insoluble contaminants and forces them to break free from the carbon pores, dispersing them throughout the cleaning solution. In this way, the purification of the micro-porous structure of activated carbon as well as its surface is achieved, enabling the desorption and reactivation of the activated carbon. It enables low-energy in-situ dynamic regeneration; the regeneration cost is low, and there is no secondary pollution. The adsorption efficiency of the regenerated activated carbon is superior to that of new carbon, being 95–130% of the latter’s efficiency. The loss rate of activated carbon is less than 0.3% per regeneration, allowing for a long service life and recyclability, as well as low costs. Contact Engineer Duan via WeChat at 18171595827.