The Design And Application Of The Control Scheme Of Biomass Direct-Fired Boiler

With the rapid development of economy and society, human demand for energy is increasing. In recent years, the reserves of fossil energy are dwindling and the environmental pollution caused by the use of fossil fuel is becoming more and more serious. Biomass has gradually caught the attention all over the world as a type of new and clean energy. The direct combustion power generation technology is currently the most common and most mature method in using biomass energy. Till now, the water-cooled vibrating-grate boiler technology developed by Danish BWE has become more and more mature, and it has greatly improved the efficiency of the power generation unit.Due to the special properties of biomass fuels such as straw, there are significant difference between the biomass-boilers and the coal-fired boilers in structure and combustion control scheme. The conveying system, the combustion process and the ash and slag handling systems are more complicated. This paper made a in-depth analysis of AnHui MengCheng’s 1 × 30MW 130t/h vibrating-grate boiler and designed the control scheme of the combustion system, then analyzed its actual operating results as well as the problems which are still existed. Firstly, the paper analyzed the properties of biomass fuel, and briefly introduced the process equipment and the operating characteristics of biomass-direct-combustion boilers. And then compared the advantages and disadvantages of the water-cooled vibrating-grate boilers and the circulating fluidized bed boilers. On this basis, the paper focused on the main task of the combustion control system and designed the specific control program from a few aspects such as water supply, fuel supply, air volume, ventilation rate, main stream temperature and so on. Lastly, the paper designed the control logic based on the LN2000 DCS platform and the performance curves illustrated the efficiency of the control schemes. So we can conclude that the designed scheme can ensure the boiler-generator perform safely, stably and economically, which will provide a good reference for the study of the control schemes of biomass boilers later.