Experimental Research On The Polygeneration For High-value Nitrogen-containing Chemicals During Biomass Nitrogen-riched Pyrolysis

Biomass energy as a renewable energy, low energy density?difficult in collection, hard to crush restricts its large-scale application seriously in use process. Biomass pyrolysis is a promising thermochemical conversion technology, it can get three state products. Conversion of biomass for high value products is an important development direction for biomass utilization.This study focus on the biomass nitrogen-riched pyrolysis to obtain nitrogen containing chemicals, this paper choose two kinds of rich-nitrogen method- urea impregnation and pyrolysis in NH3 atmosphere, the pyrolysis raw materials is sawdust and corn stalk, we carry out relevant test in fixed bed to obtain target product, it can provide a theoretical basis for biomass high-value application.Firstly, we use TG-FTIR to research pyrolysis characteristic of urea, the pyrolysis experiments at different temperature was carried out in a fixed bed, the TG curve tell us that urea start to break out at 160?, the main product is NH3 and CO2, the release of NH3 reached the peak at 503 s, the release of CO2 includes two peaks, it reached the peak at 957 s, after urea-impregnation pyrolysis of sawdust, the bio-oil including a little amides and containing nitrogen heterocyclic, the char surface contains a large number of functional groups including C-N and C=N structure; with the increase of temperature, the content of nitrogen in pyrolysis char decrease and increase in bio-oil, it illustrate high temperature is beneficial for the increase of nitrogen transfer to oil.The sigle componet of cellulose and lignin being impregnating use different mass fraction urea solution was studied by PY-GC/MS, select different heating rate?different temperature and impregnation ratio as research object. The results of GC/MS analysis contains the pyrrole, oxazolidione, nitriles. And generate in high temperature, The content of nitrogen-containing chemicals is relatively small, it may be associated with liglin structure. Cellulose has a very big difference in the pyrolysis products of different heating rates, at low heating rate under the condition of 5?/min, the pyrolysis products contains large number of hydrogen azide and urea molecules, it may be because at low heating rate is not conductive to the volatile and urea.Finally, we use NH3 as pyrolysis atmosphere to carry out the study, sawdust and corn stalk was used on different temperature and residence time and flow rate of carrier gas under different conditions. The result of GC-MS analysis of the sawdust and corn stalk pyrolysis oil contains large number of nitrogen-containing chemicals, reached more than 80%, temperature and carrier gas flow rate has a significant effect on the oil component. with the increase of temperature and flow rate, corn stalk and sawdust showed different rules. for the corn stalk, the nitrogen-containing component reached the largest at flow rate of 200ml/min at 850?, but for sawdust, conditions for maximum yield of nitrogen-containing substances appear to at 850?, flow rate of 600ml/min. Different temperature and residence time of pyrolysis char surface reached the highest nitrogen content appeared at 850?; XPS analysis results showed that the sawdust and corn stalk showed the same regularity, there are some aromatic and aliphatic C-H bonds in 350? and 550? of the char surface. as the temperature rises gradually, C1 s fitting curve showed the functional group decomposed at high temperature. that aromatic ring C=C bond in the sawdust and corn stalks accounted for the vast majority according to the peak area. The char surface also contains a small amount of aromatic C-H bond; nitrogen compounds generated in the low temperature is mainly amides and N-Q, at high temperature, char surface will mainly for the pyrrolic nitrogen and pyridine type nitrogen.