农林废弃物双级催化热解及重整的优化试验研究
发布时间：2019-01-03 12:30
【摘要】：本论文采用催化热解十催化重整双级催化反应工艺以获得高品质的生物油。针对传统的生物质催化热解工艺催化剂积碳严重、热解油品质不高等问题,论文从催化剂和原料两个方面开展工作：催化剂方面,采用EDTA化学改性方法、Py-GC/MS和管式炉实验装置探索合适的改性时间使得催化剂在保证催化效果的同时,最大程度的降低催化剂积碳量；原料方面,采用生物质与高有效氢碳比物质共催化的方法,探究不同质量比、不同工艺方法对热解产物分布和催化剂积碳的影响。采用EDTA化学改性方法,并借助XRD、低温氮气吸附和NH3-TPD技术探究不同改性时间对HZSM-5分子筛晶体结构、孔道结构和酸强度分布的影响。EDTA改性方法能够有效脱除HZSM-5表面的骨架铝,改性时间为2h的催化剂(简称EDTA-2H)与HZSM-5物理参数最接近。单级和双级Py-GC/MS实验证实了添加白云石催化剂的积极作用和EDTA的改性效果。EDTA-2H相比于HZSM-5具有更高的有利组分含量(81.91%)和更少的积碳量(1.98%)。采用管式炉装置进行双级催化热解实验,热解产物以酸类为主,随后依次为醇类、糖类、呋喃类和酮类等,有利组分含量从直接热解的31.86%增加至52%-53%,HZSM-5和EDTA-2H在产物分布和有利组分含量上无明显区别,但EDTA-2H积碳量更小,仅为2.85%。HZSM-5和EDTA-2H双级催化连续性和催化剂多次再生实验研究结果表明,催化剂的活性并非使用1次后即减小,EDTA改性能够延长催化剂失活时间和再生使用次数,EDTA-2H抗积碳性能上优于HZSM-5。因此,EDTA改性的积极效果在管式炉实验装置得到进一步的验证。聚丙烯和玉米秸秆单级共催化热解克服了生物质单独催化热解油品质差和HZSM-5积碳严重等缺点,二者在热解过程中存在明显的协同作用,当质量比为1：1时,烃类含量达到71.7%,含氧有机物中不利组分达仅为6.49%,催化剂积碳量为1.92%。双级共催化中,白云石与原科质量比为1：2时,油产率最高,为25.5%,烃类含量达到86.03%,催化剂积碳量最少,为2.55%,相对于单级芡催化而言,积碳量有所增加。因此,无论是单级还是双级共催化,均能够显著提高热解油品质和降低积碳量。积碳催化剂存在两个典型失重阶段：室温至200℃C和300℃至650℃,分别对应于水和积碳的失重,水分失重占整个失重量的70%到85%。采用Coats-Redfern法和DAEM简化模型计算积碳失重阶段的活化能,Coats-Redfern法拟合过程中,0.5反应级数明显不符合实际,对于1、1.44和2级而言,拟合度和活化能随着级数的增加和增加,DAEM模型计算与实际值具有较高的吻合度,计算结果与同为1级的Coats-Redfern法拟合结果存在很大的差异性,但与1.44级较为接近。
[Abstract]:In this paper, two-stage catalytic pyrolysis + catalytic reforming process was used to obtain high-quality bio-oil. In order to solve the problems such as serious carbon deposition and low quality of pyrolysis oil in traditional biomass catalytic pyrolysis process, this paper carried out work from two aspects: catalyst and feedstock: the method of EDTA chemical modification was adopted in the aspect of catalyst. Py-GC/MS and tube-furnace experiment equipment explore the appropriate modification time to ensure the catalytic effect and reduce the amount of catalyst carbon as much as possible at the same time. In the aspect of raw materials, the effects of different mass ratio and different process methods on the distribution of pyrolysis products and the carbon deposition of catalyst were investigated by co-catalysis of biomass with high effective hydrogen / carbon ratio. The crystal structure of HZSM-5 molecular sieve was investigated by means of EDTA chemical modification method, XRD, low temperature nitrogen adsorption and NH3-TPD technology. The influence of pore structure and acid intensity distribution. EDTA modification method can effectively remove the skeleton aluminum on HZSM-5 surface. The catalyst (EDTA-2H) with modification time of 2h is the closest to the physical parameter of HZSM-5. The positive effect of dolomite catalyst and the modification effect of EDTA were confirmed by single-stage and two-stage Py-GC/MS experiments. Compared with HZSM-5, EDTA-2H has higher favorable component content (81.91%) and less carbon deposition (1.98%). A two-stage catalytic pyrolysis experiment was carried out in a tubular furnace. The pyrolysis products were mainly acids, followed by alcohols, sugars, furans and ketones, etc. The beneficial components increased from 31.86% of the direct pyrolysis to 52-53%. There is no significant difference between HZSM-5 and EDTA-2H in product distribution and favorable component content, but the carbon deposition of EDTA-2H is much smaller, which is only the result of two-stage catalytic continuity of 2.85%.HZSM-5 and EDTA-2H and multiple regeneration of catalyst. The activity of the catalyst does not decrease after one use. EDTA modification can prolong the deactivation time and regeneration times of the catalyst, and EDTA-2H is superior to HZSM-5. in the resistance to carbon deposition. Therefore, the positive effect of EDTA modification is further verified in the tube furnace experimental device. The single-stage co-catalytic pyrolysis of polypropylene and corn straw overcomes the disadvantages of poor oil quality and HZSM-5 carbon deposition in biomass pyrolysis alone. There is an obvious synergism between the two in the pyrolysis process, when the mass ratio is 1:1. The hydrocarbon content is 71.7, the unfavorable component of oxygen-containing organic matter is only 6.49 and the amount of catalyst carbon accumulation is 1.92. In the two-stage co-catalysis, when the mass ratio of dolomite to the original family is 1:2, the oil yield is the highest, 25.5, the hydrocarbon content reaches 86.03, and the catalyst carbon accumulation is the least, which is 2.55%, compared with the single-stage Euryale. Carbon deposits have increased. Therefore, both single-stage and two-stage co-catalysis can significantly improve the quality of pyrolytic oil and reduce carbon deposition. There are two typical weightlessness stages in the catalyst: room temperature to 200 鈩，
本文编号：2399361
[Abstract]:In this paper, two-stage catalytic pyrolysis + catalytic reforming process was used to obtain high-quality bio-oil. In order to solve the problems such as serious carbon deposition and low quality of pyrolysis oil in traditional biomass catalytic pyrolysis process, this paper carried out work from two aspects: catalyst and feedstock: the method of EDTA chemical modification was adopted in the aspect of catalyst. Py-GC/MS and tube-furnace experiment equipment explore the appropriate modification time to ensure the catalytic effect and reduce the amount of catalyst carbon as much as possible at the same time. In the aspect of raw materials, the effects of different mass ratio and different process methods on the distribution of pyrolysis products and the carbon deposition of catalyst were investigated by co-catalysis of biomass with high effective hydrogen / carbon ratio. The crystal structure of HZSM-5 molecular sieve was investigated by means of EDTA chemical modification method, XRD, low temperature nitrogen adsorption and NH3-TPD technology. The influence of pore structure and acid intensity distribution. EDTA modification method can effectively remove the skeleton aluminum on HZSM-5 surface. The catalyst (EDTA-2H) with modification time of 2h is the closest to the physical parameter of HZSM-5. The positive effect of dolomite catalyst and the modification effect of EDTA were confirmed by single-stage and two-stage Py-GC/MS experiments. Compared with HZSM-5, EDTA-2H has higher favorable component content (81.91%) and less carbon deposition (1.98%). A two-stage catalytic pyrolysis experiment was carried out in a tubular furnace. The pyrolysis products were mainly acids, followed by alcohols, sugars, furans and ketones, etc. The beneficial components increased from 31.86% of the direct pyrolysis to 52-53%. There is no significant difference between HZSM-5 and EDTA-2H in product distribution and favorable component content, but the carbon deposition of EDTA-2H is much smaller, which is only the result of two-stage catalytic continuity of 2.85%.HZSM-5 and EDTA-2H and multiple regeneration of catalyst. The activity of the catalyst does not decrease after one use. EDTA modification can prolong the deactivation time and regeneration times of the catalyst, and EDTA-2H is superior to HZSM-5. in the resistance to carbon deposition. Therefore, the positive effect of EDTA modification is further verified in the tube furnace experimental device. The single-stage co-catalytic pyrolysis of polypropylene and corn straw overcomes the disadvantages of poor oil quality and HZSM-5 carbon deposition in biomass pyrolysis alone. There is an obvious synergism between the two in the pyrolysis process, when the mass ratio is 1:1. The hydrocarbon content is 71.7, the unfavorable component of oxygen-containing organic matter is only 6.49 and the amount of catalyst carbon accumulation is 1.92. In the two-stage co-catalysis, when the mass ratio of dolomite to the original family is 1:2, the oil yield is the highest, 25.5, the hydrocarbon content reaches 86.03, and the catalyst carbon accumulation is the least, which is 2.55%, compared with the single-stage Euryale. Carbon deposits have increased. Therefore, both single-stage and two-stage co-catalysis can significantly improve the quality of pyrolytic oil and reduce carbon deposition. There are two typical weightlessness stages in the catalyst: room temperature to 200 鈩，
本文编号：2399361
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