Evaluation Of Modified Cu-based Oxygen Carrier In Pine And Their Co-gasification Characteristics

World development leads to a sustained increase in energy needs. To develop and utilize renewable energy in an efficient way will play a positive role in solving global energy shortage and climate change. Biomass energy, which is a form of renewable energy, is forth in the total energy consumption, behind coal, oil and natural gas. And biomass energy is the only one of the renewable energy on earth which can be stored and transported. Because biomass energy is characteristic of widespread, great reserves, and has great exploitation, as a kind of alternative energy, has caused the attention of the researchers. Biomass gasification is a promising way of biomass utilization, but it needs to provide rich oxygen gas and high temperature steam as gasification agent, which will lead to a complex process. So, some researchers proposed a new method of chemical looping gasification?CLG? recently. The technology is low consumption of energy, little pollution to environment, and can also capture the CO₂ produced in the gasification process. So it has broad prospects in the research, but the process has a high request for the oxygen carrier. Among in them any oxygen carriers participating in gasification, the copper oxygen carrier has high activity, low prices, and no pollution to the environment, and is focused in this paper. But it has characteristics of low melting point and poor cycle performance, the inert carrier needs to be added to change its activity.Based on traditional biomass chemical chain, first of all, thermogravimetric analyzer were used in experiment, an inert carrier was added to improve the oxygen releasing properties of copper oxygen carrier. Then, Gibbs free energy minimization method is used to process thermodynamic analysis on the copper oxygen carrier and biomass gasification chemical chain, and optimize the influencing parameters, which provided theoretical basis for experiment. Next, the fixed bed reactor were used in experiment, and different factors impact on modified copper oxygen carrier oxygen release characteristics and biomass chemical chain reforming producing syngas characteristics were studied. Last, the scanning?SEM? and XRD infrared analyzer were used to analyze the characterization of synthetic oxygen carrier before and after the reaction. The results of thermodynamic analysis are shown as follows:?1? CuO shows a good cycle characteristics and release oxygen after adding MgAl₂O₄. Pure CuO under nitrogen atmosphere, due to the low melting point, it is easy to sintering, so increasing the temperature will reduce its cycle performance. And it can be seen from the TG curve that adding the inert carrier MgAl₂O₄ to the CuO the times of continuous loop reaches 18 cycles, and the circulation characteristics are almost the same. So, modified CuO is a kind of oxygen carrier with good cycle characteristics and sintering resistance.?2? The molar ratio of CuO / C, the gasification temperature, pressure, and steam / biomass?referred to as the S / B? ratio of the average mass are playing the important roles in the gasification process. Adding a certain amount of oxygen carrier in the biomass gasification benefits the formation of high calorific value gas, such as CO and H₂, but excess amount of oxygen carrier in the process will occur subsidiary reaction. So, the molar ratio of CuO/C is 0.35, and the mass ratio of CuO/biomass is 3:4. The increase of temperature is beneficial to the formation of high calorific value gas?such as CO and H₂?, but considering the sintering and circularity problem of oxygen carrier, the temperature of biomass chemical chain reforming is under 1000?. So, when the CuO is used as the gasification oxygen carrier, in this paper, the experiment temperature is selected as 700 950 ?. Improving the pressure will depress the production of CO. With the increase of pressure, CO₂ content increases, but the content of combustion gas decreases. So, the atmospheric pressure is more advantageous to biomass gasification chemical chain effect. Properly increasing the amount of water vapor in the biomass gasification process improves the yield of CO, but excess water vapor reduces the temperature in the reactor, and absorbs heat of oxygen carrier, and lowers carbon conversion rate. So, it is important to add moderate water vapor in the reactor for improving the gasification result. And when the mass ratio of water vapor/biomass is around 2, the carbon conversion and gasification efficiency reach the maximum.?3?The characteristic on the pine/CuO the appropriately increasing the gasification temperature can increase carbon conversion and gasification synthesis gas production, and the right amount of water vapor can be improved gas heating value and carbon conversion rate. Properly increasing the gasification temperature can improve the carbon conversion and gasification syngas production. However, the gas with high temperature does not have high low calorific value. With the increase of the temperature, the methane content is reduced, and the methane content plays an important role for gas calorific value. Adding water vapor in the biomass gasification process has some effects on biomass gasification. Adding moderate water vapor improves the gas heat value and the carbon conversion rate, but an excess of water vapor will lower the temperature of the gasification hall and the carbon conversion rate. The results of characterization of body of carrying oxygen analysis are shown as follows: adding the inert carrier MgAl₂O₄ in the biomass gasification process improves the ability to resist the sintering of CuO obviously.?4?The activation energies pine fixed carbon conversion rate shows degradation with the gasification process. The TG curve and DTG curve of oxygen carrier and pine before and after the modification are compared and analyzed. The results show that the copper oxygen carrier after added inert carrier MgAl₂O₄ makes pine gasification effect better and fixed carbon conversion rate higher. Because the reaction temperature rises continuously, the CuO is easily to be sintering. And its smelting point can be effectively improved by modification.