The Cost Efficiency of Reactivating Oil Regeneration Adsorbents

We define oil regeneration as a restoration of used oil to its new like condition. In this article we’ll talk about oil regeneration, using GlobeCore equipment as an example. The calculations demonstrated that the largest expense is the cost of the adsorbent. The other significant issue is waste adsorbent disposal. Knowing and understanding the problem our clients faced, we spent quite some time looking for a solution. The result is adsorbent reactivation equipment, the CMM-4RP unit.

The operating principle of the CMM-4RP adsorbent reactivation unit

The СММ-4RP addresses two problems:
  • Reduction of oil regeneration costs by multiple reuse of adsorbent;
  • The costs of used absorbent disposal.
Logistic services for new adsorbent delivery also become unnecessary. The principle of adsorbent reactivation is based on controlled burning of the substances deposited on the surface of the adsorbent with limited supply of air. The equipment can run in automatic mode. The process of loading and unloading adsorbent columns is manual. The number of possible sorbent reactivation cycles depends on its contamination, physical properties as well as the correct selection of processing conditions. Using the adsorbent through 400 reactivation cycles is not unheard of. On average, the number is about 250. Adsorbent capacity is reduced after each reactivation, which means that while the sorbent will be usable, the amount of liquid material it can purify, will decrease by several percent after each reactivation cycle.

Adsorbent life cycle: an example calculation

Consider the following example. Initially, the adsorbent was used to process 600 kg of compressor oil. After reactivation, the adsorbent was again used to process 584 kg of oil (the degree of oil regeneration quality, i.e. at which point the oil is no longer considered regenerated is determined by the operator visually or by express testing oil samples).  In the first cycle we processed 600 kg, that is, 100%. In the second cycle we processed 16 kg less (600-584=16 kg), which constitutes 2.7%. We can estimate that after the next reactivation, the adsorbent will be capable of processing approximately 16 kg less oil, more precisely – 2.7% less than the previous cycle. Therefore, after the first reactivation, the remaining adsorbent lifetime can be calculated. In the results, the adsorbent can still be used after 120 reactivation cycles, but will only be capable to regenerate 300 kg per cycle. The decision is yours: either you continue using the adsorbent or change it.  Somebody prefers to change the sorbent and says that the sorbent was reactivated 120 times, another operator used it until complete exhaustion and reports 300 reactivation cycles. The conclusion: it is worth to reactivate the adsorbent if is it used regularly. If the adsorbent is only used to regenerate oil once a year, an investment in a CMM-4RP type unit will probably take a long time to return.

Cost-efficiency of oil regeneration with subsequent sorbent reactivation

Seeing is believing, as the proverb has it. Let us calculate the efficiency of using a CMM-4RP type unit in combination with a UVR-450/16 regeneration rig. In the cost-efficiency of regenerating oils with adsorbents:
  • Adsorbent cost = $150;
  • Oil lot in the adsorbent – 62.5 kg (oil oil at $0.35) = $21.9;
  • Electricity (30 kW) – $2.
Summing up: we had 1000 kilograms of contaminated oil ($0.35 per kg) for a total of  $350. We obtain 937 kg of purified oil ($1.5 per kg) for a total of $1405.5 (with oil loss factored in). The difference is 1405.5-350=$1055.5. Deduct sorbent cost ($150), filter amortization ($0.7) and electricity ($2) and we arrive at $902.8. The profit (or economy) on one ton of oil is $902.8. Now to the return on equipment investment, say, a UVR-450/16. Its basic listed price varies from $34,000 to $38,000. It is now apparent, that the unit pays for itself after regeneration of 50 tons of oil! The UVR-450/16 can run for 20 hours straight (allowing 4 hours for sorbent change) at the rate of 200 kg per hour, i.e. 4 tons per day. Purification of 50 tons of oil will take 13 full days or 39 eight hour work days. UVR-450/16 oil regeneration unit Our oil processing results in 12.5 tons of used adsorbent (for the purposes of cost-efficiency, I figured in its loss at 25% of processed oil weight). The client now faces the problems of disposal and delivery of new adsorbent, there is also the $7,000 cost of the new adsorbent. These are the problems that we created this adsorbent reactivation unit for. The CMM-4RP can regenerate approximately 350 kg of adsorbent, which is exactly one load of the UVR-450/16. With 700-800 kg of adsorbent in stock (a double load, half is in use, the other half is reactivated), the UVR-450/16 can be run without down time! I.e. for the processing of 50 tons of oil we don’t need 12.5 tons of adsorbent, we only need 0.8 tons! Moneywise, this amounts to $7,000 economy, plus the added bonus of eliminated shipment cost. This adsorbent will pass only 13 reactivation cycles (for regeneration of 50 tons of oil). Suppose the adsorbent lifetime is 130 cycles and its final capacity is 50%, which allows to regenerate 250-400 tons of oil. Furthermore, we would need 100 tons of adsorbent to process 400 tons of oil: a whooping $55,000 expense! With the cost of the CMM-4RP somewhere around $52,000, the unit pays for itself after regenerating the first 400 tons of oil, the equivalent of 104 full days of non-stop operation (approximately 3.5 months), or a year of 8 hours a day operation.

Conclusions

The bottom line: the cost of the UVR-450/16 + CMM-4RP +1 ton of adsorbent = $90,600,  and will pay for itself after regenerating $90,600/900 (profit per ton) = 100.7 tons of transformer oil. This will take about 25 full days of work or 75 regular 8 hour work days! Just think about it: after regenerating 100 tons of transformer oil, you now own a great equipment suite, which will be continue to generate profit, save your money and the planet’s resources for many years to come! The final choice is always with the client. I only stated the facts and gave a rough method of calculation. In the next article, I plan to introduce you to the CMM-R type systems, which combines all the benefits of the UVR and the CMM-4RP units (this time without the need to reload the adsorbent). Oil regeneration and sorbent reactivation occur in the same columns!
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