Research on key technology and equipment for cultivation of Spirulina platensis from the CO2 capture from exhaust smoke

Abstract

This paper presents the results of experimental research on key technology and equipment for cultivation of Spirulina platensis from the CO₂ capture from the smoke of rice husk boiler with the climate conditions in Viet Nam. The experimental cultivation of Spirulina platensis in the Zarrouk medium were conducted in the 1 litter of volume’s photobioreactor which has stirred with aeration pump. Experimental results show that the temperature changes every day in a fairly wide range from 25 to 40 ^oC and get over the optimal temperature for growth of Spirulina platensis 30 to 38 ^oC but not much at noon time; when blowing from the smoke of steam boiler with the suitable temperature and stirring simultaneous by the circulating pump; at the same time the CO₂ absorption process into water was occurred and converting it into HCO_3-, as a suitable substrate for Spirulina platensis is easy to assimilate; the biomass concentration of Spirulina increases from 0.1 to 1.81 g/l and the pH of suspension increases from 8.5 to 10.2 after the stage’s first time of 7 days of cultivation with Zarrouk medium and since the eight days to 16th day of the cultivation is steaming stage from boiler with period of 30 minute into the above medium that containing 7.76 % CO₂ for maintaining the pH of solution from 8.5 to 9.5. The smoke of steam boiler that has CO₂ in which blow to supply the carbon nutrient source in the formation of HCO_3-, to maintain the pH value in the range of 8.5 ¸ 9.7 and increase biomass productivity to 2.53 g/l simultaneously. The photosynthetic rate of algae biomass was compared with the cultivation of Spirulina platensis under the same conditions like that using the pure CO₂ and non-using the pure CO₂ and the results in two of the above conditions are equivalent. This research is basis for constructing equipment and building a technology process in which utilizing CO₂ from exhaust gas for Spirulina platensis cyanobacteria’s cultivation with the aim of reducing green-house gas CO₂ in industry.