Glass-lined reactors for active pharmaceutical ingredient manufacturing

Diagram of glass lined reactors

Glass lined reactor model

In Pharmaceutical industries, we come across processes handling acids and sticky materials in batch reactors. Most bulk drugs are manufactured in batch wise operations. Acid reactions and crystallization operations were performed in stage wise repeatedly from initials raw materials treatment to final purification of the product. Active pharmaceutical ingredient abbreviated as API is the key compound of the drug designed to perform treatment to the health problems. Regulatory bodies like FDA (Food and Drug Administration) strictly advices and inspects the cleaning of the reactors that are used for processing API. Drugs like Nizatidine, Sertraline HCl and Fluconazole stick to the surface of stainless steel reactor even after thorough cleaning with water and methanol their trace are found by conducting the swab test. The glass-lined reactor solves this problem of contamination.

Equipment Description of Batch Type Glass-lined Reactors:


Basic reactor model contains the blue coloured glass lining inside its surface. Dome is fitted to the cylindrical vessel by “C” type clamps placing food grade gasket between them and the vessel has an opening at the bottom. The hemispherical dome has provision to fit thermocouple, agitator, dip rod and baffles. Dome and every part exposed to the API are glass lined. Heat transfer to the reactants in the reactor is provided by circulating the heating media like steam through the circular tubes fitted outside the vessel mostly half pipe jacket was used. PTFE lined accessories are used to prevent the stress during the assembly on the nozzles for dip tubes and spargers. Sleeve with PTFE lined are used for mounting the accessories on the doom.

Types of external baffles used to improve the flow pattern:

  • Fin baffle
  • d-type baffle
  • h-type
  • Finger baffle
  • Beaver-tail baffle

For performing distillation and cleaning operations, these glass-lined reactors also have provision for reflux line, a vapour line, nitrogen purge line, and vent line. Some of the merits and demerits of the glass-lined reactor are:



  • Easy and effective cleaning operation between batches
  • Suits for batch distillation
  • Withstands to acidic and ionic solutions
  • Prevent scale formation
  • Glass fragile nature
  • Difficulty to repair the breakage section
  • Low operating pressure

Research conclusion:

Liquid phase chemical reactors with microchannels in glass-lined reactors:

Mixing of two or more solutions must occur to undergo the chemical reaction in the liquid phase which is controlled by the contact pattern. Devices that enhance the rapid mixing are the interest of researchers in the field of diffusion mass transport. The key factors they concentrate in research are

  • Micromixer technique
  • Flow maintains by lamina phenomena
  • Continuous flow device designing

Glass-lined reactors if fabricated from micro level then batch models can be replaced with the continuous model so that active pharmaceutical ingredients can be manufactured continuously.