Study On The Automation System And Equipment Of Photobioreactor For Continuous Hydrogen Production With Solar Energy

This study was supported by National Natural Science Foundation“Research onmetabolic heat and continuous photohydrogen production from straw biomassultrafine powder”(NO.50976029) and National863High Technology Research andDevelopment Projects“Key technology research and demonstration of biologicalhydrogen production”(NO.2012AA051502).Energy is an important material foundation for social economic sustainabledevelopment. In the face of the current energy tension and environmental pollution,building a new renewable energy development and utilization system with green cleanenergy and creating a good living environment for mankind is an inevitable choice forsocial progress.As a friendly environmental clean energy, hydrogen gains highattentions by all the countries in the world. Bio-hydrogen production not only can useorganic wastes as raw materials to reduce the pollution of the environment,but alsocan get clean hydrogen energy, it has become one of the most important methods toproduce hydrogen. Especially the hydrogen production by PSB(photosyntheticbacteria) with efficient utilization of solar energy can achieve efficienttransformation,so it has a broad potential. However, hydrogen production by PSBwith solar is impaired by kinds of environmental factors such as temperature, Ph, lightintensity, the research of environmental factors controllable system and equipmentto enable the photosynthetic hydrogen production continuous and stable has importantsignificance for industrial and scale hydrogen production by PSB.This paper in the base of analysis the influence factors of biological hydrogenproduction process applied automatic control technology to the continuous hydrogenproduction system by PSB with solar, established controllable parameters of thereaction system based on the requirements of technological process, realized theautomatic continuous inspection and control of photosynthetic hydrogen productionsystem to ensure stable and efficient hydrogen production of PSB in the bestenvironment for the growth conditions, provided a basic data and reliableexperimental platform for the research and development of continuous hydrogen production technology of PSB with solar energy.The main research results of this paper are as following:1．Based on the analysis of environmental factors of biological hydrogen productionand characteristics of photosynthetic bioreactor, combined with process automaticcontrol technology, an experimental platform of automatic continuous hydrogenproduction of PSB with solar was established, provided an equipment conditionfor the in-depth study of the operating laws. The system used microprocessortechnology to make low cost, real-time display for easily online test. Firstly, thesystem can set the expected value of the variable by the microcontroller keyboardor software and regulate them decided by the controller to meet the different testconditions and to enhance its usefulness. Secondly, the system can pre-regulate theon-line single parameter to determine its feasibility, so the repeatability andcomplexity was reduced greatly. The controller devices have two modes ofoperation: automatic mode and manual mode, the devices also have the function asfollows: automatic operation, automatic adjustment and automatic protection andso on, and ensure the reliability and continuity of the hydrogen production. In thestructure，this system used modular design and redundant optimization, not only toensure relatively independent of the each subsystem which can make a crash haveno effect on the operation of other system, but also to have the excess interface tofacilitate the functional expansion and data migration.2．The automatic temperature control system was established by using solar heatexchange temperature compensation, utilizing adopting on-line automaticregulation based on mathematical model, adopting the three-wire PT100platinumresistance bridge to detect the temperature of the photobioreactor and adopting themicrocontroller PID control mode to realize the auto-regulation. By using thecombination of solar hot water heating and photovoltaic electric auxiliary heatingwithout external energy，the cost of continuous operation was reduced.3．In the Ph value control system，a self-mixing lye dispenser was designed and theself-control model was established by using double-loop PID fuzzy control rules tokeep the Ph value within an appropriate range after its nonlinear effect wasoptimized. The flow control system can keep the flow at0.072m3/h in parallel"short path" mode, and0.144m3/h in the serial "long path" mode, the two modescan meet the best retention run time requirement.4．An automatic level switch for the right angles cooling catheter of optical fiber condenser outdoor was designed.The water was changed automatically after thenatural evaporation,thus the device can not only avoid temperature overheating tothe fiber, but also avoid mixed pitting in catheter affecting light transmission. Forthe problem of the surface of the obscuring attachments in light tubes, anautomatic early warning device was setted to prompt its need of manuallyknocking down and cleaning.5．The results of automation equipment of photobioreactor for continuous hydrogenproduction with solar energy show that each system has perfect function and goodregulation to meet the design goals and the stable operating requirements.Temperature factors enhance the hydrogen production was obvious, which reached10-15%; PH factors follows, in the range of8-10%; and the flow factors effect wassmaller, only3-5%.It shows that in the process of continuous photosynthetichydrogen production with solar maintaining，an appropriate temperature is animportant condition to improve the hydrogen production. The flow is not a majorinfluencing factor as long as it maintains a optimal hydraulic retention time. Theautomation equipment of photobioreactor for continuous hydrogen productionwith solar energy runs continuously for40days in the controlled environment of30±2℃temperature、7±1Ph and36h hydraulic retention time.The overall systemwas continuous and stable.It enhanced the hydrogen production rate of20-30%and the efficiency of hydrogen production rate of20%and played a significantrole in promoting continuous hydrogen. The research of automation system andequipment provided a scientific reference for further research and development ofphotobioreactor for continuous hydrogen production with solar energy.