Synergetic effect during the co-pyrolysis of Naomaohu coal and cotton stalk
In the co-pyrolysis process of coal and biomass,the mixing mode significantly affects the interaction between volatile compo-nents,which in turn affects the distribution of products.In this study,the co-pyrolysis products distribution,composition,and properties of Naomaohu coal(NMH)and cotton stalks(CS)under four mixing modes,which is separated placement(Case 1),mechanical mixing(Case 2),coal in the upper layer of cotton stalks(Case 3),and coal in the lower layer of cotton stalks(Case 4).Combined with the fractal theory,the pore characteristics of co-pyrolysis char were studied,and the synergistic effect of co-pyrolysis was explored.The re-sults show that the synergistic effect of NMH and CS varies with different mixing modes,and the mixing mode has a significant impact on the distribution and properties of co-pyrolysis products.In Case 4 method,the co-pyrolysis tar yield is the highest,15.94％,which is 3.89％higher than the theoretical calculation value,and the positive synergistic effect is the most significant.At this point,the hydrogen rich components generated by CS pyrolysis interact with the volatiles of NMH pyrolysis in a timely manner,which result in a decrease in the yields of H2,CH4,and C2-C4 compared to the theoretical values,and an increase in the co-pyrolysis tar yield.Different mix-ing modes have a negative synergistic effect on the light oil in co-pyrolysis tar.The decrease in the oxygen-containing compounds may be due to the co-pyrolysis process promoting deoxygenation reactions(such as decarboxylation and decarboxylation),further generating fatty hydrocarbons,and reducing the occurrence of cross-linking reactions of oxygen-containing functional groups.During the co-pyrolysis process,·H radicals and active oxygen-containing groups have a positive synergistic effect,promoting the transfer of O,N,and S atoms in tar to solid or gas products.From the fractal dimension of char,the fractal dimensions D1 and D2 of the char are between 2-3,indica-ting that the roughness and pore structure of the char meet the basic characteristics of the fractal structure.For Case 3 and Case 4 meth-ods,the surface of the sample char located in the lower layer is rougher.The CS-C obtained by Case 3 method has smaller pores;while the pores of NMH-C obtained by Case 4 method are more uneven and the pore structure is more complex.
NETL
NSTL
万方数据
