Updated: July 2002

1. Purpose

Through our long term engineering development, based on our experience in the recovery of relatively low concentrations of Sulfuric-Acid Solution (approx. 10-15 wt%) being used in the Viscous-Rayon production process, we have established a technology to recover a high concentration of Sulfuric-Acid Solution (Max. approx. 95 wt%).
A highly concentrated Sulfuric-Acid of high purity can be recovered from various kinds of Waste Solutions of Sulfuric-Acid, as well as, Valuables contained in the Waste Solution.

2. Performance (Reference in a petro-chemical company)

Recovered Sulfuric-Acid : 75 wt%
Water Evaporated : 8,750 kg/h
Heating Steam Required : 8,300 kg/h (approx.)

3. Principle and Features

Almost all conventional type Sulfuric-Acid Concentration Systems are batch type, which have several disadvantages, such as low heat-efficiency, unsatisfactory operation rate and an expensive maintenance cost caused by corrosion. In order to avoid the said disadvantages, this system is kept under a high vacuum, which allows a lower temperature evaporative concentration, and it also enables the use of cheap regular industrial materials for the plant.
Moreover, the continuous system equipped with multi-effect Evaporators is realized having many features as follows:
1) Lower Plant Cost
Regular industrial materials are able to be used for the plant which results in lower initial cost and lower maintenance cost.
2) Lower Utility Cost
Continuous multi-effect Evaporators of the Energy Saving type results in lower utility cost.
3) Low Temperature Operation Under High Vacuum
100 - 200ºC evaporation temperature gained by keeping the plant under high vacuum, allows the plant to have a long life and to be extremely safe.
4) Long Continuous Operation is available
Continuous operation for long periods is available, thanks to the less scaling by the higher flow velocity of the Acid through the Forced-Circulation System by the selection of special pumps having high efficiency.
5) Minimum Acid Loss
The improvement of the operating conditions, as well as, the development of the high efficiency Demister, results in Acid loss of less than 0.5 wt%.
6) Smaller Space Requirement
Because of the Continuous Concentration System, the equipment is able to small, and the space required is much less.
7) Small Cost For Operation Management
The Full Automatic Control System provides easy and accurate managing of the Acid concentration, which results in cost reduction of operation management.

4. Example

5. Flowchart