Development Of On-line Monitoring System For Citric Acid Solid Bran Koji Equipment

The continuous development of industry causes both energy and environment problems.Solid-state fermentation is widely used because of its low cost,less industrial wastes emissions,and low energy consumption.It can effectively reduce energy consumption of fermentation and solve serious environmental pollution issues.Citric acid is one of microbial products with highly commercial value.It is widely used in food industry,pharmaceutical,textile,daily chemical,construction and other industries.Traditional solid-state fermentation process for producing citric acid bran koji has many problems,including a large amount of labor and high probability of bran koji dye bacterium.In order to effectively solve these problems,this paper used the drum-type solid-state fermentation equipment with the vaccination line access to the sealed fermentation tank.After steam sterilization of both the fermentation tank and the solid material,the inoculation fluid will be sprayed evenly to the surface of solid materials through the inoculation pipeline.In order to achieve complete material sterilization,the whole process will be finished in the reactor tank,including cooling,inoculation and fermentation.This way can effectively prevent contamination of bacteria in the fermentation process and ensure pure solid training.In the whole fermentation process,PLC control system is used to automatically control the parameters.The King View software is also used for real-time measurement and control.All these control equipment can provide a suitable environment for mycelium growth and determine suitable parameters for aspergillus Niger solid-state fermentation.The optimum parameters can be used to provide guidcace for the design of fermentation reactors and the large-scale preparation of critics acid.This paper focuses on the determination of technological process,design of control system,sensor selection,editing of control software in detail during the production process of citric acid bran koji.The following conclusions can be obtained from this research.The drum-type solid state fermentation reactor is suitable for the production of citric acid bran koji.The control software used in this experiment can maintain operating parameters stable.The optimal parameters during fermentation process is:temperature:35±2?,ventilation ratio:1:2,relative air humidity:80%,oxygen content:>15%,carbon dioxide content<25%,fermentation time:6 days.Citric acid bran koji under these parameters can well meet industrial requirements.