PERSONAL COMPUTER-BASED CONTROL AND MONITORIBG SYSTEM FOR BIODIESEL ALGAE PHOTOBIOREACTOR

Abstract

Growing of Algae for biodiesel production has gained popularity in recent times. This is becausebiodiesel from algae has an economic advantage over other oil crops. The oil content that can beextracted from microalgae biomass depends on the culture conditions and microalgae species. Thismeans that besides selecting the best microalgae species, it is also necessary to ensure and maintain thebest culture conditions for optimal biodiesel production. Optimum algae growth conditions can be bestbe provided by a Controlled Environment Bioproduction System (CEBS) for the algae called as photo-bioreactor (PBR). This paper reports design and fabrication of a PC based control system for a PBRproduction system for algae being developed at the School of Biosystems and EnvironmentalEngineering (SoBEE) in Jomo Kenyatta University of Agriculture and Technology (JKUAT) in Kenya.The control system is intended to ensure that optimum PH, temperature, nutrients content; lightintensity/duration and salinity of growth medium for algae are maintained. The paper covers the designand fabrication of the PC control and monitoring system. The control and monitoring system consists ofa computer program and a microcontroller connected to sensors and actuators. The computer program(master) provides the graphical user interface (GUI) consisting of control buttons and means for realtime data logging and analysis as well as real-time simulation of PBR activities. It is available inexecutable file that can be run in any windows OS computer. The microcontroller program (slave)provides the means for connecting sensors and is used to measure as well as monitor the conditions inthe PBR tanks. Communication between the computer program and the microcontroller is achievedthrough the universal serial bus (USB). The control system consists of both open and closed loopsystems. The open loop system is used to control the light duration at predetermined intervals of time.The closed loop system is used to control the nutrient concentration, light intensity, PH and oxygen:carbon dioxide ratio.