光生物反应器加热系统的设计与应用

Design and application of photobioreactor heating system

针对微藻在生长过程中对温度要求较高,需要保持在适宜的温度范围内,设计了以Siemens S7-200 PLC组成微藻光生物反应器的控制系统。该光生物反应器加热系统利用温度传感器采集藻液中温度信号,将信号输入到PLC中。PLC对温度信号进行运算,输出信号控制加热棒工作,实现了藻液冬季温度的自动恒温控制。经过试验表明,该加热系统在藻液温度设定值为30℃时,温度超调不超过1.5℃,超调量小于7.5%,静差小于±0.5℃,具有控制精度高、稳定性好的优点。光生物反应器采用该加热系统后,藻液的光密度由0.29增长到1.28,污水中的COD的去除率达到79.3%,TN的去除率达到65.07%,TP的去除率达到83.03%,因此该光生物反应器加热系统可以用于微藻的培养,并且微藻在光生物反应器内对污水的处理效果较好,具有良好的应用前景。

During growth process,microalgae is more demanding for temperature,and need to keep it in suitable ranges. The photobioreactor heating system based on Siemens S7-200 PLC was designed. The control system collects the temperature signal by temperature sensor,than put the signal into the PLC. PLC operates the signal,and output signal to control the operation of heating rods,achieved the microalgae automatic temperature control in winter. Results showed that the temperature overshoot does not exceed 1.5℃,the overshoot less than 7.5%,the static error less than ±0.5℃,when the temperature setting is 30℃. So the photobioreactor heating system has high control precision,good reliability. After application of the heating system,optical density of the microalgae increased from 0.29 to 1.28,COD removal rate reached 79.3%,TN removal rate reached 65.07%,TP removal rate reached 83.03%. Therefore,photobioreactor heating system can be used to cultivate the microalgae,and the microalgae can treat the waste water efficiently,so it has good application prospects.