Integrated process of coal pyrolysis with dry reforming of low carbon alkane over Ni/La_2O_3-ZrO_2 with different La/Zr ratio

摘要

Integrated coal pyrolysis with dry reforming of low carbon alkane (CP-DRA) is an effective method to improve tar yield. The development of dry reforming catalyst is the key for the integrated process. Ni/La2O3 shows a good performance in improving tar yield during CP-DRA, but the carbon deposition of catalyst is still a lot. To solve this problem, Zr was used as modifier to prepare Ni/La2O3-ZrO2 with different La/Zr ratios (1:1, 2:1, 4:1 and 8:1) by co-precipitation to improve catalyst stability. Results indicated that Ni4LaZr (La/Zr ratio being 4) shows a good performance and high anti-carbon deposition in DRA and CP-DRA as compared to other catalysts. The highest tar yield of CP-DRA over Ni4LaZr at 600 ?C is 20.5 wt.%. Ni4LaZr catalyst also shows a good regenerability, and tar yield keeps at 20.3 wt.% within 5 times regeneration, indicating a good stability of Ni4LaZr. The high performance and stability are due to the formation of a stable pyrochlore La2Zr2O7 and present of excess La2O3 in Ni4LaZr that can inhibit carbon deposition.