1. Preparation of pure steam in biopharmaceutical plants
From the functional classification, the pure steam system consists of two parts: preparation unit and distribution unit. Pure steam generators usually use industrial steam as a heat source, and use heat exchangers and evaporation columns to exchange heat and generate steam, thereby performing effective vapor-liquid separation to obtain pure steam. Currently, two common pure steam preparation methods include boiling evaporation and falling film evaporation.
The boiling evaporative steam generator is essentially a traditional boiler evaporation method. The raw water is heated and converted into steam mixed with a few small droplets. The small droplets are separated by gravity and re-evaporated. The steam enters the separation part through a specially designed clean wire mesh device and then enters the distribution system through the output pipeline. Various points of use.
Falling film evaporation steam generators mostly use the same evaporation column as the first effect evaporation column of the multi-effect distilled water machine. The main principle is that the preheated raw water enters the top of the evaporator through the circulation pump and is evenly distributed into the evaporation row through the distribution plate device. A film-like water flow is formed in the tube, and heat exchange is carried out through industrial steam; the liquid film in the tube is quickly evaporated into steam, and the steam continues to spiral up in the evaporator, passing through the vapor-liquid separation device, and becomes pure steam from pure The steam outlet is output, and the residual liquid entrained with pyrogen is continuously discharged at the bottom of the column. A small amount of pure steam is cooled and collected by the condensation sampler, and the conductivity is tested online to determine whether the pure steam is qualified.
2. Distribution of pure steam in biopharmaceutical plants
The distribution unit mainly includes distribution pipe network and usage points. Its main function is to transport pure steam to the required process positions at a certain flow rate to meet its flow, pressure and temperature requirements, and to maintain the quality of pure steam in compliance with pharmacopoeia and GMP requirements.
All components in the pure steam distribution system should be drainable, the pipelines should have appropriate slopes, an easy-to-operate isolation valve should be installed at the point of use and a guided steam trap should be installed at the end. Since the working temperature of the pure steam system is very high, for biopharmaceutical factories, a properly designed pure steam pipeline system itself has a self-sterilizing function, and the risk of microbial contamination is relatively small.
Clean steam distribution systems should follow the same good engineering practices and typically use corrosion-resistant grade 304, 316, or 316L stainless steel pipe, or integrally drawn pipe. Since cleaning steam is self-sterilizing, surface polish is not a critical factor and the piping must be designed to allow for thermal expansion and drainage of condensate.
