Turbo Saturation (version 3.0)

The principle of « Loopback » (return circuit)

The operating principle of Turbo Saturation lies in the closed circuit (Loopback), which allows the cascading of 2 or more saturators (here 4), and which considerably reduces gas losses and therefore reduces the smell of ClO2 where the operation is performed.

As for the products, it will suffice to multiply the quantity of CS-25% and HCl-4% according to the total volume of water to be saturated.

Normally it takes 1.3ml of each product per 100ml of water, for saturation.

As we do the complete reaction in a single operation, we must therefore double the quantity, i.e. 2 x 1.3 = 2.6ml per 100ml of water.

From experience I have noticed that in the case of Turbo-Saturation, a little more product was needed, count 1.5ml / 100ml / saturation.

This gives us a quantity of 3.0ml per 100ml, since there will only be one saturation.

In this example I made 7.2 liters of CDS in one Turbo-Saturation, so I needed the following quantities of each product: 3.0ml / 100ml * 7200ml = 216ml which I generously rounded up to 220ml.

There are a number of videos showing this principle which inspired me, including one commented by Dr. Kalcker himself. I optimized the system by adding the recycling of unabsorbed gas, to limit losses. Feel free to use your imagination to find other tricks that will make this solution even better.

Flowsheet

Legend:

0. Pump

1. Reactor

2. Bottle overflow

3. Saturator #1

4. Saturator #2

5. Saturator #3

6. Saturator #4, etc.

7. Small gas expansion tank

a) Connecting the Pump to the Reactor

b) Connecting the Reactor to the Overflow Bottle

c) Connecting the Overflow Bottle to Saturator #1

d) Connection of Saturator #1 to Saturator #2

d') Connection of Saturator #2 to Saturator #3

d") Connection of Saturator #3 to Saturator #4, etc.

e) Connection (Recycler) of the last Saturator to the Gas expansion tank (Return circuit)

f) Connection of the gas expansion vessel to the pump

Reality

Principle of operation:

The reaction between Sodium Chlorite [ NaClO2 ] (25%) and Hydrochloric Acid [ HCl ] (4% or 5%) takes place in the reactor (6) heated to approximately 60°C in a water bath (5) , to speed up the reaction.

The resulting Chlorine Dioxide [ ClO2 ] is conveyed by a flow of air coming from the pump (3) through the silicone pipe (a) then going, through the silicone pipe (b) to the saturator (8) which contains water at 4°C or it will be absorbed in water.

Note: By plunging the pipe (a) almost to the bottom of the reactor, the mixture is also stirred.

Note: You can also put the saturator in a container with ice, but if its water is very cold it will not be necessary given the duration of the saturation.

This gas is then diffused into the water in the saturator by the aquarium bubble stone (9), in order to be absorbed there.

The unabsorbed gas is then evacuated:

Either towards the 2nd saturator (10), through the silicone pipe (c), or it will be diffused into the water of the saturator by the aquarium bubble stone (11), in order to be absorbed there.
Or to the waterproof box (2) containing the air pump, through the silicone hose (d) in order to be recycled.

If only one saturator is used, its gas outlet will then be directly connected to the silicone pipe (d), in order to send the unabsorbed gas to the sealed box (2) containing the air pump or it will be recycled.

֍ In this way the unabsorbed gas is not lost,
but returns to the saturation circuit ֍

The reaction is complete when the mixture in the reactor has become light yellow in color (same or even lighter than the color of CDS).

Bonus: as there is practically no gas leakage, you can therefore do this saturation inside.

Legend:

0. The Pump.

Suction/pressure diaphragm pump. The outlet of the pump is equipped with a non-return valve.

The Reactor (800ml Coke bottle (1)).
This size of the "Reactor" is sized for a total saturation capacity of 8 Liters. We can consider that it takes about 100ml of reactor per liter of water to be saturated, to allow an active reaction without risk of overflow.
The Overflow Bottle (500ml Coke Bottle (1)).
This bottle is intended to receive a possible overflow due to a reaction that is a little too violent. This bottle is weighted with rocks so it won't tip over, as it's supposed to stay empty.
The Saturateur #1 (Bottle of coke 2L (1)).
The Saturateur #2 (Bottle of coke 2L (1)).
The Saturator #3 (Bottle of Coke 2L (1)).
The Saturator #4, etc. (1.2L Coke bottle (1)), oops! no 2L bottle on hand.
A Small gas expansion vessel.
The holes in the cover to pass the tubes are intentionally sized not to be completely sealed, thus allowing leakage to compensate for over- or under-pressure.

a) Connection from the Pump to the Reactor (2)

b) Connection from the Réacteur to the Overflow bottle (2)

c) Connection from the Overflow bottle to the Saturator #1 (2)

d) Connection from the Saturator #1 to the Saturator #2 (2)

d') Connection from the Saturator #2 to the Saturator #3 (2)

d") Connection from the Saturator #3 to the Saturator #4, etc. (2)

e) Connection (Recycler) from last Saturator to the Gas expansion vessel (loopback circuit).
This is the connection that makes the difference with the saturations in ordinary cascades, by recovering the gas which escapes from the last saturator to re-inject it into the circuit.

⭍ Pump power supply.

(1) Recovered Coke bottle. I use these bottles because they are pressure resistant and have the same screw thread as the special caps of CO2 reactors for aquariums.

(2) Silicone tube (do not use PVC which reacts with CDS), wrapped by phone charger cable protector, to stiffen the tube and thus prevent it from bending and obstructing the circuit.

Note : All bottles (1 to 6) are equipped with special bottle caps for CO2 reactors (Aquarium supplies).

These caps allow you to fix the silicone tubes in a tight way (like a serto) on the outside, and the tube of the aquarium air diffusion bubble stone, on the inside.

The 4 saturators are immersed in an ice bucket to maintain the cold temperature, the water in these saturators having been refrigerated overnight prior to the operation.

Principle of operation :

The reaction between Sodium Chlorite [ NaClO2 ] (25%) and Hydrochloric Acid [ HCl ] (4% or 5%) takes place in the reactor (1).

Note: I no longer heat the reaction, because of the risk of explosion given the quantity of product used. It must be said that here, the ambient temperature is permanently above 30°C.

The silicone tube (a) carries a stream of air from the pump (0) and plunges to the bottom of the reactor in order to stir the reaction well.

The resulting Chlorine Dioxide [ ClO2 ] is drawn by the flow of air from the pump through the silicone tube (b) to the overflow bottle (2), then to the first saturator (3) which contains cold water, where it will be diffused with an aquarium bubble stone to be absorbed.

The saturators are preferably placed in a container of ice water in order to maintain the coldest possible temperature, which facilitates the absorption of the gas in the water.

The gas not absorbed in this first saturator (3) is then evacuated to the 2nd saturator (4), through the silicone pipe (d), where it will be diffused by the bubble stone in order to be absorbed there, and so on in succession (d’, 5, d”, 6, etc.), until the last saturator of the circuit.

The air/gas flow leaving this last saturator is finally “recycled” by the pipe (e) towards the small gas expansion tank (7) before returning to the pump and leaving again in the circuit.

The reaction is considered complete when the mixture in the reactor has become light yellow in color (almost even lighter than the color of CDS).

In my last production, the reaction lasted about 35 minutes. I then let the pump run for another 30 minutes to balance the concentration (color) in all saturators.

The measurement of the concentration of CDS in ppm, will be done systematically on the last saturator, since it is the one furthest from the reactor.

Note: Although there is practically no ClO2 gas escaping, it is still advisable to carry out the operation in a well ventilated place, you never know...

Equipment :

1 air pump (0) with suction/pressure membrane as well as its electrical supply, with a non-return valve.

Special bottle caps of CO2 reactors for aquariums. These caps have the same thread as Coke bottles.

Note : The number of caps needed will be equal to the number of saturators plus 2 (one for the Reactor and one for the overflow bottle).

Note : You can also simply drill 2 holes a little smaller than the diameter of your silicone hose in the original bottle caps.

1 x Aquarium bubble stone per saturator, for gas diffusion in the water, plus one for the reactor.
Note : The bubble stone is not needed in the reactor, a simple dip pipe will do to agitate the mixture.

Enough silicone tubing to connect all that stuff, as well as telephone cable protector, to stiffen the silicone pipes which can sometimes bend and block the passage of the gas.

Conclusion

This method makes it possible to make large quantities of CDS in record time. But if you take into account the time of installation and cleaning of the equipment, it still takes a good half day.