Research On Gasification Utilization Technology Of Traditional Chinese Medicine Waste Slag Based On Chemical Looping Technology

Energy has always been an important resource for human survival and development.As of 2017,China has been the country with the largest increase in global energy consumption for 17 consecutive years.Due to China’s large population and large industrial demand,China has been facing energy pressure.China is a big country in the production of traditional Chinese medicine.It produces tens of thousands of tons of Chinese medicine slag each year,mostly by landfill treatment.How to realize the resource utilization of waste medicine residue is an important task currently facing.Chemical looping gasification technology does not require air separation and can produce high quality syngas at low cost,which is an important trend in the development of gasification technology.Applying chemical looping technology to the gasification of waste Chinese medicine slag and realizing its resource utilization is a potential Chinese medicine residue treatment technology.In this paper,the red mud,which is also industrial waste,is used as the gasification oxygen carrier,and the experiment is designed by thermogravimetric analyzer and vertical tube furnace.Firstly,the calcination temperature of red mud oxygen carrier was screened.The calcination temperature was 1050℃,1150℃and 1250℃respectively.The mixture of N₂ and CO was used as the reducing gas.The test analysis was carried out by a thermogravimetric analyzer,and finally an oxygen carrier having a calcination temperature of 1050℃was selected as an oxygen carrier for the gasification reaction.The thermogravimetric test tests the premixed sample of Chinese medicine slag fuel and red mud oxygen carrier to find that the oxygen carrier has a positive effect on the gasification of traditional Chinese medicine slag.In the interval from 800℃to the end of the temperature rise and constant temperature,the oxygen carrier promotes the reaction of CO₂ to the carbon fixed in the traditional Chinese medicine slag.In order to further explore more suitable gasification reaction conditions,a small fluidized bed experiment was carried out in a vertical tube furnace.From the comprehensive experimental results,the quality of the oxygen carrier:the quality of the traditional Chinese medicine residue=4:1 is more favorable for the preparation of H₂,CO synthesis gas,the proportion of CO in the synthesis gas produced by other proportions of samples is higher and the ratio of H₂ is too low.In the selection of the reaction temperature,it is preferably 950℃.When the reaction temperature is too low,the oxygen carrier cannot react,and the thermal decomposition of the traditional Chinese medicine slag is insufficient,and the synthesis gas yield is low.For the introduction of water vapor,when the water vapor flow rate is 3 g/min,the produced synthesis gas is produced in a high yield,and the introduction of water vapor is favorable for the production of H₂,and is more favorable for the preparation of synthesis gas.Finally,XRD,SEM,EDS,BET and other characterizations were used to analyze the evolution of physicochemical properties of oxygen carriers before and after the reaction.The results show that the crystal structure of the red mud carrier is relatively stable before and after the reaction,and the iron element in the oxygen carrier is present in the form of Fe₃O₄ after reduction.The addition of water vapor facilitates the retention of the pore structure of the oxygen carrier.It can be seen that the red mud carrier is an ideal gasification carrier.