本文選題：二氧化碳 + 中空纖維膜　； 參考：《浙江大學》2014年博士論文

【摘要】：基于液態(tài)吸收劑的燃燒后碳捕集技術(shù)是目前短時間控制燃煤電站CO2排放最為有效的方法。在其中,基于中空纖維膜技術(shù)的CO2吸收和解吸工藝由于具有較高的吸收傳質(zhì)通量和低CO2再生能耗,被認為是具有前景的技術(shù)。但是對于CO2膜吸收和膜解吸來說,如何選擇合適的吸收劑和提高運行的穩(wěn)定性是當前亟待解決的問題。本文從吸收劑的角度出發(fā),分別對膜吸收／解吸過程的吸收劑的開發(fā)、過程的模擬優(yōu)化和膜的運行穩(wěn)定性等問題進行系統(tǒng)深入的探討。 在單一吸收劑方面,首先對有機胺吸收劑化學結(jié)構(gòu)與CO2膜吸收／解吸的關(guān)系進行了系統(tǒng)研究。具體通過吸收劑結(jié)構(gòu)中氨基數(shù)目、氨基上活性H原子數(shù)目、碳鏈長度、官能團位置和大小等對CO2吸收／解吸特性的影響進行分析。該分子結(jié)構(gòu)與性能的關(guān)系研究可為未來胺類吸收劑的選擇和結(jié)構(gòu)預(yù)測提供經(jīng)驗指導(dǎo)。此外,建立了吸收劑綜合評價體系,研究發(fā)現(xiàn)：TEPA和EDA為CO2膜吸收推薦的最優(yōu)吸收劑；MDEA是CO2膜解吸中最為推薦的吸收劑,其次為TETA、DEA和EDA。此外,提出高溫CO2膜吸收概念,對24種氨基酸鹽吸收劑進行一系列的遴選實驗,以尋找最適合高溫CO2膜吸收的CO2吸收劑。在高溫CO2膜吸收實驗中,研究發(fā)現(xiàn)肌氨酸鉀吸收劑表現(xiàn)最優(yōu)的CO2吸收性能。 在混合吸收劑方面,建立二元混合胺吸收劑的理論傳質(zhì)模型,并對混合胺吸收劑的配比準則和機制進行研究。該理論的傳質(zhì)模型預(yù)測的總傳質(zhì)系數(shù)與實驗值具有較高的吻合度。研究發(fā)現(xiàn),推薦的最優(yōu)的混合吸收劑組成為：對MEA/MDEA,MEA主體濃度為30wt%,MDEA的比例在0.1-0.3之間；對DEA/AMP, DEA主體的濃度為15wt%,AMP的比例在0.5-0.8之間；對MDEA/PZ, MDEA的主體濃度為20wt%,PZ的比例在0.3左右。 以CO2反應(yīng)動力學、MEA-H2O-CO2氣液平衡(VLE)模型和流體傳質(zhì)理論為基礎(chǔ),建立了MEA吸收劑富液的CO2膜解吸的二維數(shù)學模型。該模型模擬結(jié)果與文獻報道的實驗結(jié)果吻合度良好�；谠撃Ｐ�,對膜解吸過程中關(guān)鍵操作因素例如溫度、壓力、液相流速和吹掃蒸汽,以及膜接觸器的參數(shù)影響進行了敏感度分析。最后對CO2膜解吸運行條件進行了優(yōu)化,最優(yōu)的運行壓力在20kPa左右。 在膜的穩(wěn)定性方面,選擇MEA、THAM和KS三種吸收劑,在60℃下分別研究其對PP膜的濕潤機理以及長期膜吸收運行中膜阻力的變化。研究發(fā)現(xiàn)跨膜壓差對總傳質(zhì)系數(shù)有著非常大的影響,跨膜壓差越大,將會導(dǎo)致更高的膜濕潤程度。在研究的3種吸收劑當中,KS吸收劑由于具有高表面張力,因此相對其它吸收劑,其對膜的濕潤程度要更弱。 最后對CO2膜解吸的運行能耗進行分析和優(yōu)化評估。對MEA吸收劑來說最優(yōu)的再生能耗運行工況為再生壓力20kPa左右。在此運行壓力下MEA吸收劑具有的最低CO2膜解吸再生能耗,與傳統(tǒng)熱再生進行比較,可以發(fā)現(xiàn)相對于熱再生可以降低能耗28%。在研究的所有單一有機胺吸收劑當中,MDEA具有最低的C02膜解吸再生能耗,其次為EDA和DEA。此外發(fā)現(xiàn),如果在C02膜解吸中能夠避免采用吹掃蒸汽或電廠具有豐富的低品位廢熱提供C02膜解吸的所需的熱耗,再生能耗的優(yōu)勢將會更加明顯,存在更好的工業(yè)應(yīng)用前景。
[Abstract]:The CO2 absorption and desorption process based on liquid absorbent is the most effective way to control the CO2 emission of coal - fired power plant in a short time . In this paper , the CO2 absorption and desorption process based on hollow fiber membrane technology is considered to be a promising technology . However , it is urgent to solve the problem of how to select suitable absorbent and improve the stability of operation because of the higher absorption and mass transfer flux and low CO2 regeneration energy consumption .

In the aspect of single absorbent , the relationship between the chemical structure of the organic amine absorbent and the absorption / desorption of CO2 is studied . The influence of the number of amino groups , the number of active H atoms on the amino group , the length of the carbon chain , the position and the size of the functional groups on the absorption / desorption characteristics of the CO2 is analyzed . The relationship between the molecular structure and the performance can provide empirical guidance for the selection and the structure prediction of the future amine absorbent . In addition , the comprehensive evaluation system of the absorbent is established , and it has been found that TEPA and EDA are the best absorbent recommended for the absorption of CO2 films ;
MDEA is the most recommended absorbent in CO2 film desorption , followed by TETA , DEA and EDA . In addition , the concept of high temperature CO2 film absorption is proposed . A series of selection experiments are carried out on 24 amino acid salt absorbent to find the best CO2 absorbent suitable for high temperature CO2 absorption .

In this paper , the theoretical mass transfer model of binary mixed amine absorber is established in the aspect of mixing absorbent , and the proportioning criterion and mechanism of mixed amine absorber are studied . The mass transfer coefficient predicted by mass transfer model has a higher agreement with the experimental value . It is found that the optimum composition of mixed absorbent is : the concentration of MEA / MDEA and MEA main body is 30 wt % , and the ratio of MDEA is 0.1 - 0.3 ;
the concentration of DEA / AMP and DEA main body is 15 wt % , and the ratio of AMP is between 0.5 and 0.8 ;
The main concentration of MDEA / Pz and MDEA is 20 wt % , and the ratio of pz is about 0.3 .

A two - dimensional mathematical model for desorption of CO2 film from MEA absorber rich liquid is established based on CO2 reaction kinetics , MEA - H2O - CO2 gas - liquid equilibrium ( VLE ) model and fluid mass transfer theory . The model simulation results are in good agreement with the experimental results reported in the literature . Based on this model , the sensitivity analysis of key operating factors , such as temperature , pressure , liquid phase flow rate and purge steam , and parameters of membrane contactor , are carried out on the basis of this model . Finally , the conditions for desorption operation of CO2 membrane are optimized , and the optimum operating pressure is about 20 kPa .

In the aspect of film stability , three absorbents of MEA , THAM and KS were selected , the wetting mechanism of PP film and the change of membrane resistance during long - term film absorption were studied at 60 鈩，

本文編號：2113807