Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7606530 | Journal of Analytical and Applied Pyrolysis | 2017 | 35 Pages |
Abstract
As a potential energy resource with high content of crude oil, hydrocarbon recovery from oily sludge has attracted intensive interests. In this paper, a catalytic pyrolysis experiment of oily sludge has been conducted using HZSM-5 and Zn loaded HZSM-5 zeolites in a two-stage tubular fixed-bed reactor to recover aromatics. The physicochemical properties of HZSM-5 zeolites before and after Zn loading were characterized by XRD, FTIR, N2-adsorption and NH3-TPD. The detailed compositions of oil product samples obtained from pyrolysis at differene residence time and over modified HZSM-5 were analyzed by gas chromatography-mass spectrometry (GC-MS). Results showed that the total aromatic hydrocarbons (TAH) yield increased from 48.7% to 92.2% as residence time changed from 1.0âs to 7.6âs, indicating longer contact time led to a much higher aromatics production. However, under 7.6âs, aromatics were more concentrated on polyaromatics with three or more benzene rings. By contrast, 3.8âs was regarded as the optimum residence time for a higher aromatic yield (84.8%) and the highest selectivity (67.4%) of naphthalenes yield. The catalytic effects of Zn modified HZSM-5 were investigated under 1.9âs. The incorporation of 3% Zn enhanced the TAH yield from 58.7% to 81.0%, as well as the naphthalenes yield (from 31.5% to 67.5%). The promotion of dehydrogenation and deoxygenation over Zn modified zeolite was confirmed by a remarkable increase of the H2 and CO2 yield. Coke depositon on the catalysts was further studied by thermogravimetric (TG) and X-ray photoelectron spectroscopy (XPS) analysis. The coke was determined as polyaromatics coke due to the polycondensation reaction over HZSM-5. Moreover, longer residence time promoted the formation of coke while the loading of Zn slightly reduced it.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Bingcheng Lin, Jun Wang, Qunxing Huang, Mujahid Ali, Yong Chi,