Maojian Wang

Optimization of IGCC gasification unit based on the novel simplified equilibrium model

The increasing pollutant emissions due to the development of science and technology creates tough challenges for the whole world. As one of the main causes, the utilization of solid fuels, like coal and biomass, has attracted the attentions of researchers. To alleviate this pollution, gasification technology is widely promoted in many fields of modern industry, especially in its application for Integrated Gasification Combined Cycle (IGCC) plant. Improving the simulation of gasifier is one of the most effective and essential ways to mature gasification technology. In this paper, a novel simplified equilibrium model is proposed for IGCC gasification unit. Through the analysis of gasification mechanism, Water Gas Shift Reaction (WGSR) is verified as the control step to determine the compositions of syngas. The simplified model based on the equilibrium of WGSR is proposed, developed and validated with experimental data. Furthermore, the sensitivity analysis is completed to demonstrate the influences of key factors on syngas compositions, such as reaction temperature, oxygen feed ratio and water feed ratio. Finally, the IGCC gasification unit operation conditions are optimized and the Cold Gas Efficiency is improved approximately 10% after optimization.

Microalgae Growth Determination Using Modified Breakage Equation Model

Abstract Simulation of growth rate and cells size distribution is important in order to predict and improve productions from microalgae. Aim of this paper is to use a modified breakage equation model to calculate the growth rate, the “breakage rate” and the particle size distribution of microalgae, which are changing over the time. Differently from previous mathematical models, various stages of the life cycle of Chlorella Vulgaris have been considered. According to the experimental data, the proposed method is able to predict the growth and, similarly, it can be extended to other kind of microalgae. This wants to be a new starting point for future development of microalgae growth kinetic.

Modelling and optimization of a heat integrated gasification process

Abstract In this study, an iteration optimization is performed based on the Gibbs free energy minimization approach. Further, simultaneous optimization of a heat integrated gasification process is presented. The study shows how heat integration can improve the overall efficiency of a gasification process. We formulated a mathematical model which simultaneously optimizes the operating parameters and its interaction via heat integration among the hot syngas, steam generation and the feed preheat. This allows the model to simultaneously maximize the cold gas efficiency and also minimize the Gibbs free energy. The model also combined gasification model with an energy targeting model that is able to handle processes with variable stream temperatures and flow rates.

Simultaneous Optimization and Integration of Gas Turbine and Air Separation Unit Using Novel Simplified Model

Abstract As a promising green technology, Integrated Gasification Combined Cycle (IGCC) technology holds an urgent requirement to be upgraded by process optimization and integration. Directly power related Gas Turbine (GT) and energy intensive Air Separation Unit (ASU) in IGCC plant are selected as the target. A novel mathematical simplified ASU model is proposed to decrease the simulation complexity. It is built with GT model together using Microsoft Excel 2010. What’s more, in this paper the optimization and integration are taken simultaneously instead of sequentially to get a more efficient configuration further closing the global optimal solution. Operation conditions optimization, especially considering the pressure matching between GT combustor and ASU columns, and heat and mass integrations are considered to decrease work consumption and enhance the environmental performance. The specific performances can be demonstrated by case study results. The conclusion shows that the methodology we developed can achieve more effective operation of GT and ASU with about 3 % more power generation.