Study On Microwave-assisted Lignite Activation And Activated Coke Preparation And Desulfurization Performance

SO₂ is one of the main causes of air pollution such as acid rain and smog,causing serious health damage to the human body.The 13th and 14th Five-Year Plan outlines that strengthening environmental governance and improving environmental quality are listed as important work goals,and SO₂ emission reduction is urgent.Active coke dry flue gas desulfurization technology has been widely used because of its simple process flow,no secondary pollution,and recyclable sulfur resources.At present,the adsorption desulfurization capacity of commercial activated coke is generally small,the preparation cycle is long,and the energy consumption is high.Therefore,the study of a fast and efficient method to prepare high-performance desulfurization activated coke has attracted much attention.This paper uses Eastern Inner Mongolia lignite as raw material,microwave assisted,CO₂ and KOH activation to prepare high-performance lignite activated coke.Related samples are characterized by nitrogen adsorption and desorption,FT-IR,SEM,TEM,XRD characterization and desulfurization ability test.The effect of the addition of KOH on the microwave pyrolysis activation characteristics of lignite was studied.The addition of KOH can significantly accelerate the microwave heating rate of lignite,quickly reach the pyrolysis activation reaction temperature,and increase the maximum temperature that can be reached.The heating rate is?250?/min,the maximum temperature is above 800?.Increase the gas yield of pyrolysis activation,reduce the yield of liquid components such as tar.It has a good activation and opening effect on lignite pyrolysis coke,and the content of acidic oxygen-containing groups is greatly reduced,significantly improve its adsorption capacity.The optimal conditions for the preparation of activated coke by microwave-assisted activation were explored,and the effects of mass ratio(KOH/Coal),activation time,and CO₂ flow rate on the yield,adsorption capacity and desulfurization capacity of activated coke were investigated.Orthogonal experiment and range the analysis results show that the order of magnitude of influence on the iodine adsorption value of activated coke is:mass ratio>activation time>CO₂ flow.According to the results of orthogonal experiment and single factor experiment,the optimal preparation condition is that the mass ratio is1:1,activation Time 15min,CO₂ flow rate 300m L/min.The lignite activated coke produced under optimal conditions yields 43.8%,iodine adsorption value is 1518.6mg/g,which is more than 3 times the commercial activated coke standard,and the breakthrough sulfur capacity is 12.75mg/g,the penetration time is 468s.The characterization shows that the activated coke has a rich pore structure,the BET specific surface area is1405.8m²/g,the total pore volume is 0.951cm³/g,the micropores are concentrated,the pore channels are smooth,and they are connected to each other.Activated coke prepared under optimal conditions was used as the carrier,and metal nitrate was used as the precursor to prepare Fe,Ni,Cu supported activated coke.The effects of different metals and loadings on the desulfurization capacity of activated coke were analyzed.The order of strength of Fe/AC desulfurization capacity is 15wt.%>10wt.%>5wt.%>20wt.%,and the maximum breakthrough sulfur capacity is 30.82mg/g.The order of strength of Ni/AC desulfurization ability is 10wt.%>5wt.%>15wt.%>20wt.%,the maximum breakthrough sulfur capacity is 32.29mg/g.Cu/AC desulfurization ability is ranked 10wt.%>5wt.%>15wt.%>20wt.%,the maximum breakthrough sulfur capacity is 44.90mg/g.Desulfurization performance test shows that Cu/AC desulfurization performance is significantly better than Fe/AC,Ni/AC,the best Cu loading is 10wt.%,10wt.%Cu/AC than unloaded activated coke desulfurization capacity improved 3 times or more.SEM characterization shows that when the Cu loading is10wt.%,Cu is well dispersed.Regeneration experiments show that 10wt.%Cu/AC still has more than 90%desulfurization ability after 5 regenerations,and it has good recycling.performance.Compared with traditional heating methods,microwave pyrolysis activation is quick and efficient,and high-quality activated coke can be prepared in less than 30 minutes.In this paper,the basic research on the application of microwave-assisted activation of lignite to prepare desulfurized activated coke provides an industrial application basis for the rapid and efficient preparation of high-performance desulfurized activated coke.