本文選題：多聯(lián)產(chǎn)　切入點(diǎn)：分級(jí)轉(zhuǎn)化　出處：《南京理工大學(xué)》2017年碩士論文

【摘要】：目前,我國(guó)對(duì)于煤炭的利用大部分仍采用直接燃燒的粗放單一方式。煤炭分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用技術(shù)依據(jù)煤的組成和反應(yīng)特性進(jìn)行分質(zhì)分級(jí)梯級(jí)利用,以液體燃料和電力為目標(biāo)產(chǎn)品,實(shí)現(xiàn)煤炭資源的梯級(jí)高效利用,有效解決了所面臨的資源與環(huán)境問題。本文基于煤炭分級(jí)轉(zhuǎn)化的思想,提出了煤熱解氣化燃燒分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用技術(shù),構(gòu)建了聯(lián)產(chǎn)熱、電、甲醇及燃料油的分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用系統(tǒng),并對(duì)其開展了模擬研究以及系統(tǒng)中關(guān)鍵問題的實(shí)驗(yàn)研究。首先,利用Aspen Plus軟件對(duì)煤熱解氣化燃燒分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用系統(tǒng)進(jìn)行了全流程模擬,計(jì)算得到了系統(tǒng)熱效率、系統(tǒng)總投資、內(nèi)部收益率和投資回報(bào)周期等熱力學(xué)與經(jīng)濟(jì)性指標(biāo),并與煤熱解氣化分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用系統(tǒng)的相關(guān)指標(biāo)進(jìn)行了對(duì)比,全面評(píng)估了煤熱解氣化燃燒分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用系統(tǒng)的可行性。結(jié)果表明,煤熱解氣化燃燒分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用系統(tǒng)雖然設(shè)備投資比煤熱解氣化分級(jí)轉(zhuǎn)化多聯(lián)產(chǎn)利用系統(tǒng)高,但其系統(tǒng)熱效率更高,可達(dá)47.02%LHV,表明該系統(tǒng)具有一定的可行性。其次,搭建多氣氛熱解實(shí)驗(yàn)臺(tái)和多元混合氣氛熱重實(shí)驗(yàn)臺(tái)。開展了熱解氣氛對(duì)半焦結(jié)構(gòu)和氣化反應(yīng)特性的實(shí)驗(yàn)研究。在真空水平管式爐中制取了不同熱解氣氛的熱解半焦,采用激光拉曼光譜和氮?dú)馕降仁侄伪碚髁税虢沟奈锢斫Y(jié)構(gòu)特性。結(jié)果表明,C02熱解氣氛下制取的半焦無序化程度更高,且比表面積較大,而CO,CH4和H2熱解氣氛下制取的半焦石墨化程度較高且比表面積較小。熱重氣化實(shí)驗(yàn)結(jié)果表明,CO2熱解氣氛下制取的半焦氣化速率最高,而CO,CH4和H2熱解氣氛下制取的半焦氣化速率均低于Ar氣氛下的半焦。這可能是由于熱解過程中的C02氣化反應(yīng)、CO歧化反應(yīng)、CH4熱裂解反應(yīng)以及H2的縮合與脫氧反應(yīng)所導(dǎo)致的。然后,研究了在H20和CO2混合氣氛以及H20,CO2,H2和CO多元混合氣氛下比表面積對(duì)半焦氣化機(jī)理的影響。采用不同的熱解速率制取了具有不同比表面積的半焦樣品。實(shí)驗(yàn)結(jié)果表明,大比表面積半焦的氣化速率更符合獨(dú)立活性位Langmuir-Hinshelwood(L-H)模型假設(shè),而小比表面積半焦的氣化速率則更符合共用活性位L-H模型假設(shè)。因?yàn)榇蟊缺砻娣e半焦可提供更多的活性位,H2O與CO2分子之間對(duì)于活性位的競(jìng)爭(zhēng)較小。最后,研究了在H2O和CO2混合氣氛以及H2O,CO2,H2和CO多元混合氣氛下灰成分對(duì)半焦氣化機(jī)理的影響。采用酸洗法,制取了脫灰半焦,采用鹽溶液浸漬法,制取了負(fù)載Na鹽的半焦。實(shí)驗(yàn)結(jié)果表明,脫灰半焦的氣化速率既不符合共用活性位假設(shè)也不符合獨(dú)立活性位假設(shè)。Na鹽半焦的氣化速率接近于獨(dú)立活性位假設(shè)。因?yàn)榈V物質(zhì)脫除會(huì)降低半焦催化效果,加劇了 H2O與CO2分子對(duì)于活性位的爭(zhēng)奪。而堿金屬鹽對(duì)半焦氣化反應(yīng)起催化作用,為氣化反應(yīng)提供了更多的反應(yīng)活性位,削弱了H2O與CO2分子之間對(duì)于活性位的競(jìng)爭(zhēng)。
[Abstract]:At present, the utilization of coal in our country still adopts the extensive and single way of direct combustion.According to the composition and reaction characteristics of coal, the multi-cogeneration and utilization technology of coal classification and conversion can be used in a graded and cascade way, taking liquid fuel and electric power as the target products to realize the cascade and efficient utilization of coal resources.Effectively solve the problem of resources and environment.Based on the idea of coal classification conversion, this paper puts forward the multi-cogeneration and utilization technology of coal pyrolysis gasification and combustion classification conversion, and constructs the multi-cogeneration and utilization system of cogeneration heat, electricity, methanol and fuel oil.The simulation research and the experimental research on the key problems of the system are also carried out.Firstly, the thermal efficiency, total investment, internal rate of return and the period of return on investment of the system are calculated by using Aspen Plus software to simulate the whole process of the multi-cogeneration and utilization system of coal pyrolysis gasification and combustion classification conversion.The feasibility of multi-cogeneration utilization system of coal pyrolysis gasification and gasification was comprehensively evaluated by comparing with the related indexes of multi-cogeneration utilization system of coal pyrolysis gasification and gasification.The results show that although the equipment investment is higher than the multi-cogeneration utilization system, the thermal efficiency of the system can reach 47.02 LHVs, which indicates that the system is feasible.Secondly, a multi-atmosphere pyrolysis test bench and a multi-element mixed atmosphere thermogravimetric test bench are built.The experimental study on the structure and gasification reaction characteristics of char in pyrolytic atmosphere was carried out.Pyrolytic semi-coke with different pyrolysis atmosphere was prepared in a vacuum horizontal tube furnace. The physical structure of char was characterized by laser Raman spectroscopy and nitrogen adsorption.The results show that the char prepared in the pyrolysis atmosphere has a higher degree of disorder and a larger specific surface area, while the graphitization degree and specific surface area of the char prepared under the pyrolysis atmosphere of COG Ch 4 and H 2 are higher and the specific surface area is smaller.The experimental results of thermogravimetric gasification show that the gasification rate of char is the highest in the pyrolysis atmosphere of CO _ 2, while the gasification rate of the char is lower than that of the char in the atmosphere of COG _ (4) and H _ (2) pyrolysis.This may be due to the CO2 gasification reaction in the pyrolysis process and the pyrolysis of Ch _ 4 and the condensation and deoxidation of H _ 2.Then, the effect of specific surface area on the gasification mechanism of semi-char was studied in the mixed atmosphere of H20 and CO2 and the mixed atmosphere of H20 and CO.The semi-coke samples with different specific surface areas were prepared at different pyrolysis rates.The experimental results show that the gasification rate of large specific surface area semi-coke is more consistent with the Langmuir-Hinshelwood-L-H) model hypothesis of independent active sites, while the gasification rate of small specific surface area semi-coke is more consistent with that of common active site L-H model.Because large specific surface area semi-coke can provide more active sites between H _ 2O and CO2 molecule competition for the active site is smaller.Finally, the influence of ash composition on the gasification mechanism of semi-char was studied in the mixed atmosphere of H _ 2O and CO2 and in the mixed atmosphere of H _ 2O _ 2 CO _ 2H _ 2 and CO.The descaling semi-coke was prepared by acid washing method, and the Na salt loaded semi-coke was prepared by salt solution impregnation method.The experimental results show that the gasification rate of demineralized char does not accord with either the common active site hypothesis or the independent active site assumption. The gasification rate of Na salt semi-coke is close to that of independent active site hypothesis.Because the removal of minerals reduces the catalytic effect of semi-coke, it intensifies the competition for active sites between H2O and CO2 molecules.Alkali metal salts play a catalytic role in the gasification reaction of semi-char which provides more reactive sites for gasification and weakens the competition between H2O and CO2 molecules for active sites.
【學(xué)位授予單位】：南京理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ530.2;TQ541

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