Effects of mineral additives on catalytic pyrolysis characteristics of corn stalk powder

Abstract: Based on self-made biological tube furnace pyrolysis experiment platform, using 20 pyrolysis purpose corn stalk powder as raw materials and selecting Na2CO3, CaO, Fe2O3 as additives. Then, the additive was mixed with maize straw powder in 10% proportion by high speed rotating in situ blending method. At the same time, respectively to set the heating rate and final pyrolysis temperature as 40 ℃/min and 750 ℃, Pyrolytic raw material mixture to place inside the self-made pyrolysis reactor, reactor by means of frosted sealing (sealing way of sealing has verified), before the reactor sealed by high purity nitrogen gas bubbled into the inside of the reactor, the pyrolysis reactor residual air exchange, to ensure that the reactor of the pyrolysis is without oxygen or lean oxygen environment. In this condition, to study the effects of different additives on the in-situ catalytic pyrolysis of corn stalk powder. By analyzing the corn stalk powder production rate under the effect of different additives of pyrolysis products change curve, at the same time, to research and analysis the composition of pyrolysis gas, microstructure of coke and its element distribution form and the change in functional groups in pyrolytic liquid phase products through gas chromatograph, scanning electron microscope, energy spectrometer and Fourier infrared spectrum analyzer and other instruments and equipment. Finally, X-ray diffraction was used to detect the existence forms of various additives in coke after pyrolysis, then, according to the results of testing and combining with the yield of pyrolysis products and product changes, speculate that the additives in the process of pyrolysis. The following conclusions are drawn: Adding Na2CO3 and CaO of corn stalk powder in the pyrolysis process of the liquid yield is far lower than no additives, and the liquid yield reach the maximum at 650 ℃, is 36.39% and 37.88% respectively. Na2CO3 and CaO as the additives in the process of biomass pyrolysis of biomass tar have obvious inhibitory effect. In maize straw powder thermal cracking process, three kinds of additives on liquid oid produced have different inhibition, Na2CO3 above CaO 1.5 times, 20 times that of Fe2O3. Na2CO3 has the highest pyrolysis gas production rate in the three additives, up to 31.72%, and the thermal gas quality of CaO is the best and the low heat value of its pyrolysis gas is the highest, reaching 11.38 MJ/m3. In the process of corn stalk powder pyrolysis, Na2CO3 to promote biomass thermal cracking produces pyrolysis gas is given priority to, however, CaO to produce pyrolysis char is given priority to, and the pyrolysis product coke respectively have different forms and different degrees of coked reunion. In the low temperature pyrolysis stage, Fe2O3 effect on the yield of pyrolysis products is relatively weak, but after 550 ℃ catalytic effect is remarkable. By studying three kinds of additives in the process of pyrolysis of corn stalk powder to the influence of the yield of pyrolysis products and distribution, for later biomass catalytic pyrolysis catalyst selection and use of the aspects such as industrial and mining enterprise waste provide valuable basic data theory and direction.