本文關(guān)鍵詞：玉米、小麥秸稈原料、熱解過(guò)程及固體產(chǎn)物特性NIRS快速分析研究　出處：《中國(guó)農(nóng)業(yè)大學(xué)》2016年博士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 玉米秸稈 小麥秸稈 熱解 基礎(chǔ)特性 快速分析

【摘要】：綜合高效利用生物質(zhì)是解決能源危機(jī)和環(huán)境污染兩大問(wèn)題的有效方法之一,其中,生物質(zhì)熱解是一項(xiàng)基本和有效的利用技術(shù)。熱解利用的基礎(chǔ)特性主要包括原料組分和熱值、熱解過(guò)程參數(shù)和熱解產(chǎn)物的燃料特性。這些基礎(chǔ)特性的檢測(cè)可為評(píng)價(jià)生物質(zhì)適用性,了解反應(yīng)過(guò)程和機(jī)理,預(yù)測(cè)反應(yīng)速率及難易程度,指導(dǎo)實(shí)際生物質(zhì)熱解設(shè)備和工藝的工程設(shè)計(jì),有效控制生物質(zhì)熱解提供數(shù)據(jù)和技術(shù)支持。傳統(tǒng)的檢測(cè)方法費(fèi)時(shí)費(fèi)力,近紅外光譜技術(shù)(NIRS)作為一種快速、高效的檢測(cè)方法,對(duì)生物質(zhì)熱解利用中原料、過(guò)程和產(chǎn)物基礎(chǔ)特性的快速定量檢測(cè)具有很大潛力。本研究選取主要農(nóng)作物秸稈玉米、小麥秸稈,基于NIRS對(duì)不同粒度原料組分和熱值進(jìn)行實(shí)驗(yàn)室和在線定量預(yù)測(cè)研究,對(duì)熱解特性、熱解活化能和低溫?zé)峤夤腆w產(chǎn)物的燃料特性進(jìn)行快速定量預(yù)測(cè)研究。研究結(jié)果表明,NIRS可以快速定量預(yù)測(cè)原料的組分和熱值、熱解特性、熱解活化能和低溫?zé)峤夤腆w產(chǎn)物的燃料特性。論文取得的主要?jiǎng)?chuàng)新性成果有：1、NIRS可以快速定量預(yù)測(cè)玉米、小麥秸稈粗粉原料的纖維素、半纖維素、木質(zhì)素、可溶性糖、水分、灰分、揮發(fā)分、固定碳、C、H、N、O、K、Mg和熱值,而對(duì)于S含量的定量預(yù)測(cè),模型需進(jìn)一步研究。粗粉光譜模型與細(xì)粉光譜模型相比,細(xì)粉模型精度高于或與粗粉模型精度相當(dāng),粗粉和細(xì)粉最優(yōu)模型的光譜預(yù)處理方式不同,表明樣品狀態(tài)不同,需要不同預(yù)處理方法。2、在線光譜采集參數(shù)對(duì)不同近紅外光譜儀器的光譜重復(fù)性影響不同,因此,對(duì)不同光譜儀需采用不同采集參數(shù),以保證光譜質(zhì)量。采用優(yōu)化后光譜儀和采集參數(shù),建立的在線模型可以快速定量預(yù)測(cè)樣品的纖維素、半纖維素、木質(zhì)素、可溶性糖、水分、灰分、揮發(fā)分、固定碳、C、H、 O、N、K、Mg、熱值,而對(duì)于S的預(yù)測(cè)效果較差。與靜態(tài)粗粉模型相比,在線模型精度與靜態(tài)粗粉模型相當(dāng)或略好。3、不同熱解速率下的熱解過(guò)程特性存在顯著區(qū)別,小麥秸稈與玉米秸稈的熱解過(guò)程特性存在顯著區(qū)別。NIRS可以快速定量預(yù)測(cè)熱解外推起始溫度、外推結(jié)束溫度、總失重率、失重率、峰值速率、最大峰溫度,模型的RSD都小于10%。玉米秸稈的活化能顯著高于小麥秸稈。活化能隨轉(zhuǎn)化率的增加先增大后減小再增大。峰值轉(zhuǎn)化率點(diǎn)對(duì)應(yīng)的活化能隨升溫速率增加無(wú)顯著變化。NIRS可以快速定量預(yù)測(cè)其熱解平均活化能及轉(zhuǎn)化率為0.3-0.6階段的活化能,模型RSD都小于10%。4、不同終溫對(duì)低溫?zé)峤夤腆w產(chǎn)物的燃料特性影響非常顯著。相對(duì)于終溫來(lái)說(shuō),不同升溫速率,不同氮?dú)獯祾咚俾蕦?duì)低溫?zé)峤夤腆w產(chǎn)物的燃料特性的影響較小。玉米秸稈低溫?zé)峤夤腆w產(chǎn)物和小麥秸稈低溫?zé)峤夤腆w產(chǎn)物的燃料特性有顯著區(qū)別。利用NIRS可以快速定量預(yù)測(cè)玉米秸稈和小麥秸稈低溫?zé)峤夤腆w產(chǎn)物的能量產(chǎn)率、質(zhì)量產(chǎn)率、熱值、揮發(fā)分、固定碳、灰分、C、H、O、 N、燃料比率,其模型交互驗(yàn)證RSD分別為4.66%、5.12%、3.29%、7.01%、7.61%、7.44%、2.10%、8.18%、5.31%、7.02%、11.89%,對(duì)水分和S含量的預(yù)測(cè)精度較低,需進(jìn)一步研究。
[Abstract]:Comprehensive and efficient utilization of biomass is one of the effective ways to solve the two major problems of energy crisis and environmental pollution. Biomass pyrolysis is a basic and effective utilization technology. The basic characteristics of the pyrolysis use mainly include the component of the raw material and the calorific value, the parameters of the pyrolysis process and the fuel characteristics of the pyrolysis products. The detection of these basic characteristics can provide data and technical support for evaluating biomass applicability, understanding reaction process and mechanism, predicting reaction rate and difficulty degree, guiding practical engineering design of biomass pyrolysis equipment and process, and effectively controlling biomass pyrolysis. The traditional detection method is time-consuming and laborious. Near infrared spectroscopy (NIRS) as a fast and efficient detection method has great potential for rapid quantitative detection of the basic characteristics of raw materials, processes and products in biomass pyrolysis. This study selected the main crop straw corn, wheat straw, NIRS different granularity of raw material composition and calorific value of laboratory and on-line quantitative based on the characteristics of fuel and low temperature pyrolysis solid product activation on the pyrolytic characteristics and the research of rapid quantitative prediction. The results show that NIRS can quickly predict the composition and calorific value of raw materials, pyrolysis characteristics, pyrolysis activation energy and the fuel properties of low temperature pyrolytic solid products. The main innovative achievements of this paper are: 1, NIRS corn and wheat straw coarse powder material prediction fast quantitative cellulose and hemicellulose, lignin, soluble sugar, moisture, ash, volatile matter and fixed carbon, C, H, N, O, K, Mg and calorific value, and for quantitative S the amount of prediction, further research is needed to model. Compared with the fine powder spectral model, the accuracy of the fine powder model is higher than that of the coarse powder model. The spectral preprocessing way of the optimal model of coarse powder and fine powder is different, indicating that different state of the sample requires different pretreatment methods. 2, online spectral acquisition parameters have different effects on spectral repeatability of different near infrared spectrometer. Therefore, different acquisition parameters are needed for different spectrometers, so as to ensure spectral quality. Using the optimized spectrometer and acquisition parameters online, the model can be samples of cellulose, hemicellulose and lignin, soluble sugar, moisture, ash, volatile matter and fixed carbon, C, H, O, N, K, Mg, and for the rapid and quantitative prediction of calorific value, the prediction effect of S is poor. Compared with the static coarse powder model, the accuracy of the on-line model is equivalent to or slightly better than that of the static coarse powder model. 3. There is a significant difference in the characteristics of the pyrolysis process at different pyrolysis rates, and there is a significant difference between the characteristics of the pyrolysis process of the wheat straw and the corn straw. NIRS can quickly and quantitatively predict the initial temperature, the temperature of the extrapolation, the total weightlessness rate, the weightlessness rate, the peak rate and the maximum peak temperature of the pyrolysis extrapolation. The RSD of the model is less than 10%. The activation energy of corn straw was significantly higher than that of wheat straw. The activation energy increases first and then decreases with the increase of conversion rate. The activation energy corresponding to the peak conversion point has no significant change with the increase of temperature. NIRS can quickly predict the average activation energy of its pyrolysis and the activation energy of 0.3-0.6 phase, and the model RSD is less than 10%. 4. The effect of different final temperature on the fuel properties of low temperature pyrolysis solid products is very significant. Compared with the final temperature, the different heating rates and different nitrogen blowing rates have little effect on the fuel properties of the low temperature pyrolysis solid products. The fuel characteristics of the low temperature pyrolysis solid products of corn straw and the low temperature pyrolysis of wheat straw are significantly different. NIRS can be used for rapid quantitative prediction of corn straw and wheat straw pyrolysis solid product yield, energy yield, quality of calorific value, volatile, fixed carbon, ash, C, H, O, N, fuel ratio, the model of cross validation of RSD were 4.66%, 5.12%, 3.29%, 7.01%, 7.61%, 7.44%, 2.10%. 8.18%, 5.31%, 7.02%, 11.89%, the prediction accuracy of water and the content of S is low, need further study.
【學(xué)位授予單位】：中國(guó)農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：S216.2
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本文編號(hào)：1339869