Study Of The Growth Kinetics Of Photosyntheticbacteria Group And Temperature Field Characteristics Of Phototobiological Hydrogen Production System

This paper is a series research supported by the National Natural Science Foundation (No.50676029) and the fund of doctor subject for scientific research projects of China (No.20060466001).The thermophysical problem during the biological production of hydrogen indirectly influenced many factors of the photosynthetic bacteria hydrogen production system such as energy consumption, the hydrogen production enzyme activity, the hydrogen production rate and so on. While, the research on the photobiological production of hydrogen mainly centralized in the aspects of hydrogen production feed and the hydrogen production conditions at the present time. The thermophysical problem of the hydrogen production had still not studied, which directly effected and confined the photobiological hydrogen production development and inhibited the development of biological hydrogen production technologies. So this paper mainly studied on the thermokinetic of photosynthetic bacteria group during the biological hydrogen production of PSB. The thermogenesis laws of biological hydrogen production were analyzed, using the thermokinetic method so that the thermokinetic parameter of photobiological hydrogen production can be obtained and the distribution regularities of temperature field in the photohydrogen production system. In addition, the thermokinetic model of photobiological hydrogen production can be built and the best PSB growth conditions, which can afford high scientific reference value to the research of reactor design and technologies of the photobiological hydrogen production.Main research result of this paper as following:1. The optimal growth conditions of efficiently hydrogen production PSB group were studied with the different conditions. The results showed that the illumination the temperature and pH value influenced on EPSBG growth, the inoculation has little influence on EPSBG growth. Under the optimal cultivation and the simulated monosodium-glutamate wastewater conditions, a kinetics model in the growth of photosynthetic bacteria in the substrate of CH₃COONa was set up. The parameters in the model are as follows: the saturation constant K_s 0.26 g.L^-1 and the maximum specific growth rateμ_max 0.044 h^-1 . The experiment results showed that this model could describe the growth data of PSB very well. With the orthogonal experiments, the best growth conditions of EPSBG were as following: 1500Lx illumination, 30℃temperature, 7 pH value, 50% inoculation.2. The temperature changes of efficiently hydrogen production photosynthetic bacteria group (EPSBG) in 500mL photobiological hydrogen production reactor were studied with glucose as substrate using single factor analytical method at the different experimental conditions. During experiments, results showed that the temperature was increased with time during the efficiently hydrogen production PSB group. Effects of initial temperature, illumination and inoculation on the system temperature, and its duration were obvious, according to variations of system, 2000Lx illumination, 30℃temperature and 10% inoculation were appropriate for the biological Hydrogen Production of PSB.3. In the course of photobiological hydrogen production the rate of system temperature changes were studied with 0.1 g/L glucose as substrate according the affecting theory of hydrogen production and low cost requirement in industry production process in the 3L reactor, using single factor analytical method.. The change rate of system temperature increased with the time during hydrogen production and the rate value was related the parameter of hydrogen production. The obvious optimal factors of EPSBG were as following: 30℃temperature, 2000-3000Lx illumination, 7.0 PH value, 10 inoculation, 72h initial activity of PSB. In a 5L photo-bioreactor with the former optimal condition of hydrogen production, the change laws of the hydrogen production productivity and hydrogen production were reached. In batch process, hydrogen production sustained 96h. During 0-36h hydrogen production rate increased with time. The maximum hydrogen production rate occurred in 36h.4. In this paper, Geometrical model was built according to the structure of photobiological hydrogen production reactor. With Ansys finite element analysis software, simulation analysis of the distribution of interior bioreactor temperature field and node during photobiological hydrogen production under different work conditions was conducted. The corresponding temperature field picture was given. The calculated results showed that the simulation results of temperature field and notes were in accordance with the experimental results. In addition, the distribution of notes temperature in reactor were uneven temperature distribution and the maximum value reached 0.23℃.So the temperature distribution of bioreactor would be non-uniform with the mass-production-scale. The large-scale production reactor must be stirred so that the temperature distribution was uniform in order to ensure using efficiently hydrogen production photosynthetic bacteria group and proceeding hydrogen production.