Leading Change: Volm Achieves Efficient Transformation of the Penicillin Crystallization Process Using Screw Vacuum Pump Technology

1.Issues With the Original System

• The original liquid-ring vacuum pump + ejector system used water as the working fluid, which comes into direct contact with organic solvents during operation, resulting in a heavy wastewater treatment burden, high energy and water consumption, and ineffective solvent recovery.

2. Process Requirements: High Vacuum and Rapid Low-Temperature Crystallization

• The production of penicillin sodium solution relies on continuously removing and condensing solvents under high vacuum, enabling the system to quickly reach a supersaturated state. This promotes rapid crystallization of penicillin at low temperature, followed by drying into powder. The crystallization process requires both low temperature and high speed—the lower the temperature, the better the quality of the penicillin. The specific conditions are as follows:

1. The vacuum degree shall not be lower than -0.097 MPa. The higher the vacuum, the shorter the crystallization time.

2. The higher the vacuum, the lower the temperature at the onset of crystallization.

1. Superior Vacuum

• Adopting Volm’s self-developed patented rotor profile (self-conjugate surface design), the pump ensures continuous and uniform meshing, effectively reducing axial leakage and significantly improving pumping efficiency and ultimate vacuum level.In actual penicillin sodium crystallization applications, its vacuum degree (-0.098 MPa) is notably superior to that of traditional liquid ring vacuum pumps (-0.096 MPa). During the crystal growth stage, it can extract an additional 400–500 liters of distillate within one hour, greatly accelerating the crystallization process.

2. Cleaner Production

• Based on a dry-running principle, no working fluid is required, fundamentally eliminating process water consumption and wastewater generation, thereby achieving energy savings and environmental protection.

3. Solvent Circulation

• Thanks to the dry, liquid-free operation and a discharge pressure higher than atmospheric pressure, solvents can be directly and efficiently condensed and recovered on the discharge side. Combined with a condensation system, approximately 0.5 liters of butanol can be recovered per production batch, enabling solvent recycling and significantly reducing material costs.

4. Internal Compression

• The internal compression design ensures uniform heat distribution within the pump, enabling stable operation and lower discharge temperature. This effectively reduces the difficulty of controlling the distillate temperature and minimizes the risk of equipment seizure. 

5. High Reliability

• For the corrosive media commonly encountered in the pharmaceutical industry, corrosion-resistant material options such as Hastelloy coating or superalloys are available, ensuring long-term stability under harsh operating conditions.

6. Easy Maintenance

• The design supports an online cleaning function, allowing pump chamber maintenance without disassembling the pump or piping, greatly reducing downtime and maintenance costs.

7. Multiple Sealing Options

• According to operating conditions, lip seals, "zero" leakage mechanical seals + PLAN23 flushing scheme, or composite seals can be provided.

Since introducing Volm screw vacuum pumps to replace the original liquid ring and ejector systems in 2015, the pharmaceutical company has successively purchased over 20 units from Volm serving the production of penicillin API. The upgrade of the vacuum equipment has not only improved production efficiency and product quality but also achieved significant environmental benefits, generating cumulative economic and environmental gains of nearly 100 million RMB.