農(nóng)林廢棄物雙級催化熱解及重整的優(yōu)化試驗研究
發(fā)布時間：2019-01-03 12:30
【摘要】：本論文采用催化熱解十催化重整雙級催化反應(yīng)工藝以獲得高品質(zhì)的生物油。針對傳統(tǒng)的生物質(zhì)催化熱解工藝催化劑積碳嚴重、熱解油品質(zhì)不高等問題,論文從催化劑和原料兩個方面開展工作：催化劑方面,采用EDTA化學(xué)改性方法、Py-GC/MS和管式爐實驗裝置探索合適的改性時間使得催化劑在保證催化效果的同時,最大程度的降低催化劑積碳量；原料方面,采用生物質(zhì)與高有效氫碳比物質(zhì)共催化的方法,探究不同質(zhì)量比、不同工藝方法對熱解產(chǎn)物分布和催化劑積碳的影響。采用EDTA化學(xué)改性方法,并借助XRD、低溫氮氣吸附和NH3-TPD技術(shù)探究不同改性時間對HZSM-5分子篩晶體結(jié)構(gòu)、孔道結(jié)構(gòu)和酸強度分布的影響。EDTA改性方法能夠有效脫除HZSM-5表面的骨架鋁,改性時間為2h的催化劑(簡稱EDTA-2H)與HZSM-5物理參數(shù)最接近。單級和雙級Py-GC/MS實驗證實了添加白云石催化劑的積極作用和EDTA的改性效果。EDTA-2H相比于HZSM-5具有更高的有利組分含量(81.91%)和更少的積碳量(1.98%)。采用管式爐裝置進行雙級催化熱解實驗,熱解產(chǎn)物以酸類為主,隨后依次為醇類、糖類、呋喃類和酮類等,有利組分含量從直接熱解的31.86%增加至52%-53%,HZSM-5和EDTA-2H在產(chǎn)物分布和有利組分含量上無明顯區(qū)別,但EDTA-2H積碳量更小,僅為2.85%。HZSM-5和EDTA-2H雙級催化連續(xù)性和催化劑多次再生實驗研究結(jié)果表明,催化劑的活性并非使用1次后即減小,EDTA改性能夠延長催化劑失活時間和再生使用次數(shù),EDTA-2H抗積碳性能上優(yōu)于HZSM-5。因此,EDTA改性的積極效果在管式爐實驗裝置得到進一步的驗證。聚丙烯和玉米秸稈單級共催化熱解克服了生物質(zhì)單獨催化熱解油品質(zhì)差和HZSM-5積碳嚴重等缺點,二者在熱解過程中存在明顯的協(xié)同作用,當質(zhì)量比為1：1時,烴類含量達到71.7%,含氧有機物中不利組分達僅為6.49%,催化劑積碳量為1.92%。雙級共催化中,白云石與原科質(zhì)量比為1：2時,油產(chǎn)率最高,為25.5%,烴類含量達到86.03%,催化劑積碳量最少,為2.55%,相對于單級芡催化而言,積碳量有所增加。因此,無論是單級還是雙級共催化,均能夠顯著提高熱解油品質(zhì)和降低積碳量。積碳催化劑存在兩個典型失重階段：室溫至200℃C和300℃至650℃,分別對應(yīng)于水和積碳的失重,水分失重占整個失重量的70%到85%。采用Coats-Redfern法和DAEM簡化模型計算積碳失重階段的活化能,Coats-Redfern法擬合過程中,0.5反應(yīng)級數(shù)明顯不符合實際,對于1、1.44和2級而言,擬合度和活化能隨著級數(shù)的增加和增加,DAEM模型計算與實際值具有較高的吻合度,計算結(jié)果與同為1級的Coats-Redfern法擬合結(jié)果存在很大的差異性,但與1.44級較為接近。
[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，
本文編號：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，
本文編號：2399361
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