DOC《功能材料 201712151015》

功能材料

201712151015 转化吸收型氧化锌基脱硫剂脱除H2S和COS性能 王泽鑫,上官炬*,刘艳霞,徐壹,杨颂,樊惠玲 (太原理工大学煤科学与技术教育部和山西省重点实验室,山西 太原 030024) 摘要:以前驱物工业活性ZnO和碱式碳酸锌分解的ZnO为脱硫剂活性组分,在引入结构助剂γ-Al2O

3、碱性助剂K2CO3改性的基础上,制备出转化吸收型氧化锌基脱硫剂.

在300 ℃、空速2000 h-1及常压下,考察了活性组分ZnO前驱物种类及不同前驱物制备的助剂γ-Al2O3对氧化锌基脱硫剂脱除硫化物性能的影响.结果表明:改性氧化锌基脱硫剂的孔隙结构和碱性显著影响其脱硫性能.与工业活性ZnO制备的氧化锌脱硫剂相比,以碱式碳酸锌分解的ZnO制备的脱硫剂对硫化氢的脱除效率和穿透硫容都更高,穿透硫容约增加10倍.不同前驱物制备的γ-Al2O3对氧化锌基脱硫剂脱硫性能有较大影响.其中,拟薄水铝石分解的γ-Al2O3显著提高了氧化锌基脱硫剂脱硫性能,穿透硫容达12.18%.以碱式碳酸锌分解ZnO为活性组分,添加拟薄水铝石分解的γ-Al2O3和碱性助剂K2CO3制备的改性氧化锌基脱硫剂对COS的脱除起到转化与吸收作用,COS转化率达99.98%,穿透硫容为4.03%. 关键词:转化吸收;

氧化锌;

助剂;

改性;

脱硫;

功能材料 中图分类号:TQ 546.5 文献标识码:A 文章编号 Performances of Conversion-absorption Zinc Oxide Based Desulfurizers for the Removal of H2S and COS WANG Ze-xin, SHANGGUAN Ju*, LIU Yan-xia, XU Yi-kun, YANG Song, FAN Hui-ling (Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China) Abstract: A series of conversion-absorption ZnO based desulfurizers were prepared by using industrial ZnO and ZnO obtained by basic zinc carbonate decomposition as active component respectively, γ-Al2O3 as structure additive and K2CO3 as basic additive. The effects of ZnO precursors and γ-Al2O3 precursors on the desulfuration properties of prepared ZnO based desulfurizers were investigated at 300℃and atmospheric pressure with a gas space velocity of

2000 h-1. The results showed that the pore structure and basicity of ZnO based desulfurizers could significantly affect their desulfurization properties. The desulfurizer using ZnO obtained by basic zinc carbonate decomposition as the active component had high removal efficiency and good breakthrough sulfur capacity, and the breakthrough sulfur capacity was increases about

10 times comparing with that of the desulfurizer using industrial ZnO as the active component. In addition, the γ-Al2O3 prepared by different precursors had influences on the desulfurization properties of the prepared ZnO based desulfurizers. The γ-Al2O3 decomposed from pseudo boehmite obviously improved desulfurization properties of the desulfurizers, the breakthrough sulfur capacity was 12.18%. Among these desulfurizers, the desulfurizer using ZnO decomposed from basic zinc carbonate as the active component, γ-Al2O3 decomposed from pseudo boehmite as the structure additive and K2CO3 as the alkaline additive, could convert and absorb COS with a COS conversion of 99.98% and a breakthrough sulfur capacity of 4.03%. Key words: conversion-absorption;

zinc oxide;

additives;

modification;

desulfurization;

functional materials Foundation items: National Natural Science Foundation of China (20976116);

2016 Major Science and Technology Project of Shanxi Province (MJH2016-03) 煤制气中存在的含硫气体(主要有H2S、COS)会致使后续合成催化剂中毒、仪器设备腐蚀、产品质量下降及生态环境破坏,最终妨碍煤制气绿色、清洁、高效地开发与利用.因此,煤制气的脱硫净化非常必要[1-2].煤制气脱硫净化方法中的干法脱硫技术因脱硫温度区域宽、精度高、效率高、可脱除多种形态硫化物等优点而被应用于精细脱除煤制气中硫化物.金属氧化物脱硫剂有Fe、Zn、Mn等氧化物[3-6]、Zn-Al、Zn-Si、Zn-Mn等复合氧化物[7-10].其中,氧化锌基脱硫剂与H2S反应热力学性能最佳,脱硫精度高,已成为常用精细脱硫剂.但氧化锌基脱硫剂存在明显不足:在煤制气含CO、CO2气氛中脱除H2S过程中产生COS,并难以精细脱除煤制气中已存在和脱硫产生的COS,而COS比H2S的负面影响更显著[11-13].Li[14]等在考察300℃下燃料电池燃料气脱硫时,发现了COS的生成,降低了氧化锌的脱硫性能. 为了减少氧化锌基脱硫剂脱硫过程中COS的生成,本课题组前期研究提出改善脱硫剂微观结构、添加改性助剂制备改性氧化锌脱硫剂,将有机硫的水解转换与无机硫的脱除相结合,降低了脱硫过程中出口COS的浓度[15-17].但并未进一步系统探讨活性组分ZnO前驱物和助剂γ-Al2O3前驱物对氧化锌基脱硫剂脱除H2S性能的影响.为了减少氧化锌基脱硫剂脱硫过程中COS的生成和实现一步脱硫过程中同时脱除H2S和COS,本文主要考察了氧化锌基脱硫剂活性组分ZnO前驱物类型、γ-Al2O3前驱物类型对制备的氧化锌基脱硫剂脱除H2S性能的影响,并探讨了改性氧化锌基脱硫剂转化吸收脱除COS的机理.