Solvent Recovery Solution for Antibiotic APIs

Problem to Solve: An antibiotic production enterprise encountered prominent problems in the recovery of butyl acetate solvent after the fermentation broth extraction process in penicillin production. The traditional vacuum distillation tower process had the disadvantages of high energy consumption, low solvent recovery rate, and unstable quality of the recovered product, which not only increased the enterprise’s operating costs but also affected the subsequent production efficiency and product quality.

Solution Implementation: To solve the above problems, the enterprise renovated the original process using a scraped surface evaporator and established a complete butyl acetate solvent recovery system. The system configuration included a scraped surface evaporator (with a heat transfer area of 15m²), a preheater, a shell-and-tube condenser, a solvent recovery tank, and a vacuum system. Key process parameters were strictly optimized and controlled to ensure recovery effect: feed temperature was maintained at 40–50℃, vacuum degree at 10–20 mmHg, scraper speed at 200–300 rpm, and heating medium temperature at 60–70℃. The scraped surface evaporator realized efficient separation and recovery of butyl acetate through rapid film formation and gentle evaporation, avoiding the defects of the traditional vacuum distillation tower.

Solution Effect & Economic Benefit: Under the optimized operating conditions, the solution achieved excellent application effects: the recovery rate of butyl acetate reached 98.5%, the purity of the recovered solvent reached 99.6%, and the residual amount of penicillin in the solvent was less than 0.1%, which fully met the requirements of subsequent production. The system could operate continuously for 30 days without failure, and the heat transfer coefficient remained stable in the range of 1500–2000 W/(m²·K), ensuring long-term stable operation.

In terms of economic benefits, the renovation brought significant cost savings and revenue growth. Before renovation, the vacuum distillation tower consumed 3.5–4.0 tons of steam per ton of solvent, with an annual operating cost of about 2.8 million yuan. After renovation, the steam consumption was reduced to 1.2–1.5 tons per ton of solvent, and the annual operating cost was reduced to about 1.2 million yuan, saving 1.6 million yuan annually. The total equipment investment for the renovation was about 1.8 million yuan, with an investment payback period of only about 1.1 years. In addition, the solvent recovery rate was increased by 3.5 percentage points compared with the original process, adding about 800,000 yuan in annual revenue for the enterprise.