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CaO affects urea pyrolysis when coalescing with melting urea, which decreased the performance of urea-SNCR deNO x process. The influence of CaO on urea pyrolysis was studied with a thermogravimetric analyzer, a fixed bed reactor, and DRIFTS. The mechanism of CaO was also analyzed. Experimental results showed that CaO decreased the pyrolysis rate of urea, especially in the presence of O 2 . NH 3 production in urea pyrolysis was not influenced by CaO, whereas HNCO in the gaseous products disappeared and CO 2 production was increased remarkably. NO, N 2 O, and CO were also produced in the presence of O 2 . DRIFTS experiments showed that Ca(NCO) 2 and CaCN 2 were produced and the composition of the solid products varied with the atmosphere. Mechanism analysis showed that CaO initially reacted with melting urea and biuret to produce Ca(NCO) 2 and release NH 3 and H 2 O. Ca(NCO) 2 decomposed to CaCN 2 and CO 2 with increasing temperature, and CaCN 2 can exist stably in the absence of O 2 because of its high thermostability. In the presence of O 2 , Ca(NCO) 2 can be oxidized to N 2 O, CO 2 , and N 2 , whereas CaCN 2 can be oxidized to NO, CO, and N 2 . [ABSTRACT FROM AUTHOR]

The interactions between high density polyethylene (HDPE) and potato during their primary and secondary co-pyrolysis process were investigated by a thermogravimetric analyzer (TGA) and a tubular furnace. Kinetic analysis has shown that the devolatilization of potato was relatively faster compared to those of cellulosic materials, which has been ascribed to the multi-side-chain structure and lower polymerization degree of starch. The pyrolysis process of potato can be divided into three stages, and the main thermal degradation took place between 178 and 378 °C, while the HDPE decomposition occurred in a single stage in the temperature range of 380–517 °C. In the case of blends, the weight loss differences (Δ W ) between experimental and theoretical ones were less than ±8% in all cases, and the co-pyrolysis process of potato and HDPE can be described as two consecutive first order reactions, the apparent activation energies of blends were almost invariable, suggested that only physical step limitation was found in the primary co-pyrolysis process of potato and HDPE. On the contrary, the results of tubular furnace experiment showed that due to the relatively long gas resident time, the interaction occurred in the gas phase not only favored the formation of gaseous products, but also improved the bio-oil quality by significantly reducing the oxygen-to-carbon ratios (O/C) of the pyrolysis oil. [ABSTRACT FROM AUTHOR]

Highlights: [•] High moisture content was conducive to the production of hydrogen rich fuel gas. [•] The steam involved in gasification and reforming reactions has a saturation value. [•] The toxic effect of tar decreased with the increase of moisture content. [•] The ejection of volatile matter was intensified by high moisture content. [Copyright &y& Elsevier]