Numerical Simulation of an Improved Updraft Biomass Gasifier Based on Aspen Plus

In this paper, numerical investigation and optimization is conducted upon an improved updraft gasifier which is expected to overcome the weakness of conventional updraft gasifier. The comprehensive Aspen Plus model of the improved updraft gasifier is based on the RYield and RCSTR reactor. The tar prediction model is constructed, and the yield of tar is determined by the volatile of biomass and gasification temperature. The Aspen Plus simulation results agree very well with experiment results for the product yields and gasification efficiency, which shows the accuracy of the Aspen Plus model. The tar content in syngas of the improved gasifier is proved to be much lower than that of the conventional one by this model. The inflection point of the gasification efficiency occurs when air ratio is 0.25, and the optimum steam proportion in the air is 7.5%. Such a comprehensive investigation could provide necessary information for the optimal design and operation of the improved updraft gasifier.

Automated summary

This paper conducts a numerical investigation and optimization on an improved updraft gasifier, overcoming the weaknesses of conventional updraft gasifiers. Using the comprehensive Aspen Plus model based on RYield and RCSTR reactors, a tar prediction model is constructed to determine tar yield. The simulation results of Aspen Plus match well with experimental results for product yields and gasification efficiency, demonstrating the accuracy of the model. The study confirms that the improved gasifier has a much lower tar content in the syngas compared to the conventional one. The inflection point of gasification efficiency occurs when the air ratio is 0.25, and the optimum steam proportion in the air is 7.5%. This comprehensive investigation provides essential information for the optimal design and operation of the improved updraft gasifier.