碩士 / 國立中興大學 / 生物產業機電工程學系 / 93 / An automatic cultivating reactor system which can be used to continuously produce the microalgal cells has been designed and developed in this research. The system was constructed and combined together with the parts of the cultivating tank, the aeration equipment, the pH value feedback control device, the stirring device, the new cultivating solution storage unit, the solution inlet and outlet control equipment, the temperature control system, the illumination device, the outer cover unit, the PLC (programmable logical controller) automatic control system and other sensors. Through the pilot tests using the set of continuous illumination, the rotation speed of the stirring shaft measured was varying between 0 and 352.7rpm and which could be adjusted and controlled using an indirect circuit frequency controller between frequencies of 0 and 60Hz. A regression equation (y=-0.04899+5.87296x) between the relation of rotation speed and frequency was also established. According to the need of the cultivating requirement, the air supply amount could be chosen from 0 to 4 l/min and the illumination condition could be changed to 4, 8 or 12 light sources with the illuminance of 2600, 3600 or 5000 lux respectively. The system temperature could be maintained between 25 and 29℃ while setting the reactor temperature at 27℃. The pH level was also held between the range of 6.5 and 7.5 as controlled by injecting an appropriate amount of the CO2 gas. Based on the cultivation period of the microalga, the ignition point of the replenishment of the new cultivating solution and the delivery of the harvesting solution could depend on the choice of the controlling methods such as the continuous mode, hand-operation, timing and turbidity, to turn on and off the solution inlet and outlet electromagnetic valves respectively to complete each cultivating cycle. The valid capacities of the cultivating tank of the reator and the storage tank of the new cultivating solution storage unit were 150 and 120 litters, respectively. This research applied Tahiti Isochrysis galbana affinis to process the foundamental tests of the effects of each relevant batch type rearing, including the factors of the inoculation amount, the salinity, the illumination period, the cultivation temperature and the ingredient concentration of the cultivating solution, and the relevant rearing tests of the reactor system. The experimental results of the foundamental batch tests showed that the optimal cultivating conditions of the inoculation amount, the salinity and the temperature were 25%, 30ppt and 25℃, respectively with continuous illumination and normal ingredient concentration of the cultivating solution. The results from the testing of the enlarging cultivation, the illumination intensity, the most growing concentration and the semi-continuous rearing of the reactor system also showed that under the cultivating conditions used with the valid cultivating volume 120 l, different illumination intensities, salinity 28±0.5ppt, pH value 7±0.5 and temperature range 25-29℃ of the reactor, the cultivation period was found under 5 days in the batch cultivation, the higher illumination intensity was better, and the most growing concentration was up to 1192×104 cell/ml. The semi-continuous cultivating tests also demonstrated that the lower dilution ratio was better. During 31 days of the automatic semi-continuous cultivating test with daily dilution ratio 16.67％, the reactor could produce a high concentration solution of the algal cell. The daily average growing concentration was up to 548×104 cell/ml with the dry weight (washing with pure water) of 0.0015g/ml, and the average concentration of the agal cell after dilution was about 395×104cell/ml. It showed that an average increasing rate per day was 150×104 cell/ml. The average daily growth rate of the front section (from day 0 to 15) was higher with the value of 0.43; however, the growth of the rear section (from day 16 to 30) was more stable with a lower daily average growth rate of 0.24. The experiments also verified that the reactor system presently developed in this reseach obtained the capability of stable and long-term cultivating functions.
Keywords : Microalgae, Automatic semi-continuous, Reactor
| Identifer | oai:union.ndltd.org:TW/093NCHU0415032 |
| Date | January 2005 |
| Creators | Shian-Ming Shiu, 許憲銘 |
| Contributors | Chung-Chyi Yu, 尤瓊琦 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 218 |
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