Beyond Conventional Adsorption: How CDOF Removes Oil and TOC from Ternary Precursor Liquor More Effectively

Background and challenges in ternary precursor liquor treatment

Ternary precursor liquor consists mainly of various saturated sulfates and has a pH of 2 to 3, making the overall treatment fairly complex. Organic solutions introduced in production leave the liquor high in oil and total organic carbon (TOC), which adversely affects the properties of the resulting material. Effectively reducing oil and TOC in the liquor is therefore a key step in safeguarding product quality.

Conventional ternary precursor liquor treatment:

Most existing processes rely on conventional adsorption, namely activated carbon plus resin adsorption. This approach has the following drawbacks:

1. Product liquor requirements mean coconut-shell activated carbon and special resins must be used, which is expensive.

2. Once saturated, activated carbon is hazardous waste and must be sent to an external contractor for disposal, adding to operating cost.

3. Operation is troublesome: the carbon must be replaced as soon as it is saturated, every two days, requiring staff on duty.

4. Resin regeneration requires ethanol, which imposes high on-site safety requirements and carries a certain safety risk.

SINOKLE’s latest ternary precursor liquor treatment process:

SINOKLE uses CDOF (integrated ozone flotation unit) with an independently developed modified heterogeneous ozone catalyst, which removes oil and TOC from the liquor well without disturbing its ionic composition or impairing its purity. It can reduce oil content, dissolved oil included, to below 2 ppm or even lower, with TOC removal above 60%.

Scheme diagram

CDOF Integrating catalytic ozonation, hydraulic cyclonic separation and flotation-based oil removal and supported by a new specially modified heterogeneous catalyst that adsorbs and catalytically oxidises oil and TOC, the process uses both adsorption and catalytic oxidation so that oil and TOC are rapidly oxidised and decomposed by ozone, dissolved oil is released and separated by demulsification, and oil removal and TOC degradation are achieved efficiently.

Compared with existing activated carbon plus resin adsorption, the technology treats water more effectively — especially as regards TOC, which activated carbon and resin barely remove — needs no frequent replacement, greatly reduces hazardous waste (saturated activated carbon and non-regenerable resin are hazardous waste), and significantly lowers treatment cost. It runs fully automatically and enclosed, is easy to operate and performs stably, and has broad application potential in the new energy sector.

Process flow diagram

Technical advantages of the integrated ozone flotation unit (CDOF):

1. Multiple technologies work together — a domestic first and an internationally leading technology.

2. High ozone utilisation, low energy consumption and relatively low operating cost, only 1/3–1/2 of activated carbon or resin adsorption, with no hazardous waste and environmentally friendly.

3. No chemical agents are added, no secondary pollution is produced and downstream processes are unaffected.

4. Fast treatment, short residence time and a small equipment footprint.

5. Enclosed and pressurised operation with no ozone leakage — safe and environmentally sound, with no impact on site operations.

6. Fully automatic and intelligent control with remote guidance, so no dedicated operator is needed.

7. A new acid-resistant catalyst that works under acidic conditions without metal contamination.

8. Oil content can be reduced to below 2 ppm, dissolved oil included, with TOC removal above 60%.