Diesel Dehydration

01 Background
The client is a large coal-to-liquid enterprise in the coal chemical industry in Ningxia, with an annual coal tar refining capacity of 100,000 tons and a finished diesel output of 10,000 tons.With the application and capacity expansion of coal chemical processes such as blue carbon and coal-to-natural gas, coal tar production has increased accordingly.The production of finished diesel and kerosene from coal tar via hydrotreating has become widespread in the northwest coal chemical industry.Especially in coal tar-rich regions, coal-to-liquid finished oil has become an important part of national energy strategic security.
02 Challenges
Previously, the client adopted a multi-stage gravity sedimentation process, relying on monthly natural gravity settling for dehydration.To meet regulatory standards, sulfides in diesel had to be removed, which required the addition of strong alkali (sodium hydroxide).This caused severe emulsification of the coal tar-derived finished diesel.Simple gravity sedimentation alone could not meet the national moisture content requirements for finished petroleum products.
If distillation were adopted, in addition to high energy consumption, the presence of azeotropic organics (phenol) would pose a risk of excessive gas emissions.In response, the client approached Zhongke Ruili through its local partner, and the issue was successfully resolved.
Solution
01 Solution
Based on Zhongke Ruili’s standard Aggregation-Induced Separation technology, the specialized standardized process CASAIS-1-COAL is applied.On the basis of satisfying organic reagent dehydration, this process further enhances the alkali resistance of the materials and the system.
The standard Aggregation-Induced Separation dehydration process features the following advantages:
Pure physical separation, no secondary addition: No gases or chemicals are added, and no new substances are introduced.
Fully enclosed system, no secondary emissions: No VOCs or hazardous oily sludge are generated.
Highly efficient and automated, no manual intervention: The system status can be monitored in the main control room.
Strong shock resistance, stable and qualified effluent: Fluctuations of 10% alkali concentration do not affect the final effluent quality.
Long service life and low operating cost: The process is simple and has achieved continuous operation for more than 3 months since commissioning.

The complete system of Zhongke Ruili Aggregation-Induced CASAIS-1-COAL Standard Dehydration Process

02 Results
After the process was put into operation, the appearance of the finished diesel changed from turbid and emulsified to clear and transparent.The moisture content of the exported diesel was measured to be below 300 mg/L, meeting the national standards for finished petroleum product sales.This effectively supports the national energy security strategy.