高温下钙基吸附剂吸附CO2的研究

CaO基吸附剂是一种理想的CO2高温吸附剂。利用热重分析仪研究了由不同前体制备的CaO高温下对CO2的吸附性能。利用吸附仪测定了各吸附剂的比表面积等参数。实验发现CaO的最佳吸附温度范围为700—750℃;由CaC2O4.H2O制得的CaC2O4-CaO具有良好的吸附性能,在实验条件下,其吸附量为理论吸附量的89.1%;在较宽的CO2体积分数范围内,CaC2O4-CaO始终保持很高的吸附性能;吸收速率的大小受吸附剂比表面积、孔体积、孔结构等参数的共同影响。高温下,CaO基吸附剂吸附CO2的微观机理有待进一步研究。     

废弃物制备钙基二氧化碳吸附剂的研究进展

新世纪以来人类活动产生了极大的碳排放量和大量废弃物,还造成了严重的资源浪费,环境成为经济发展的代价.利用二氧化碳吸附剂减少二氧化碳排放,是目前工业最有效的手段.高温钙基二氧化碳吸附剂以其成本低、性能好受到了广泛应用.利用废弃物改性制备二氧化碳吸附剂达到以废治废是一种资源节约、环境友好的研究方向.从不同钙源和不同掺杂剂的方面分类介绍了目前国内外关于废弃物改性钙基二氧化碳吸附剂的研究,对于改性后的钙基吸附剂的碳酸化转化率、循环吸附性能、作用特点等方面进行了详细阐述.     

离子液体捕集二氧化碳的研究进展(英文)

Due to their negligible volatility,reasonable thermal stability,strong dissolubility,wide liquid range and tunability of structure and property,ionic liquids have been regarded as emerging candidate reagents for CO2 cap-ture from industries gases.In this review,the research progresses in CO2 capture using conventional ionic liquids,functionalized ionic liquids,supported ionic-liquids membranes,polymerized ionic liquids and mixtures of ionic liquids with some molecular solvents were investigated and reviewed.Discussion of relevant research fields was presented and the future developments were suggested.     

环戊烷/水乳化液水合法捕获烟道气中CO_2(英文)

Capture of CO2 by hydrate is one of the attractive technologies for reducing greenhouse effect.The primary challenges are the large energy consumption,low hydrate formation rate and separation efficiency.This work presents a new method for capture of CO2 from simulated flue gasCO2(16.60%,by mole) /N2 binary mixture by formation of cyclopentane(CP) hydrates at initial temperature of 8.1°C with the feed pressures from 2.49 to 3.95 MPa.The effect of cyclopentane and cyclopentane/water emulsion on the hydrate formation rate and CO2 separation efficiency was studied in a 1000 ml stirred reactor.The results showed the hydrate formation rate could be increased remarkably with cyclopentane/water emulsion.CO2 could be enriched to 43.97%(by mole) and 35.29%(by mole) from simulated flue gas with cyclopentane and cyclopentane/water(O/W) emulsion,respectively,by one stage hydrate separation under low feed pressure.CO2 separation factor with cyclopentane was 6.18,higher than that with cyclopentane/water emulsion(4.01) ,in the range of the feed pressure.The results demonstrated that cyclopentane/water emulsion is a good additive for efficient hydrate capture of CO2.     

钙基吸附剂中纳米CaO与CO_2反应动力学模型的改进

纳米Ca O基吸附剂的吸附容量经历最初碳化和再生反应循环过程衰减后趋于稳定,研究了经过多次循环预处理后稳定的钙基吸附剂中纳米Ca O与CO2反应动力学。钙基CO2吸附剂预处理条件为碳化反应温度为600℃,再生反应温度为800℃循环42次。采用热重分析仪,在吸附温度550~630℃,CO2分压0.01~0.02 MPa条件下,测定预处理后得到的吸附剂中纳米Ca O与CO2的反应速率。通过优化气-固离子反应吸附模型的参数,拟合实验数据得到改进的反应动力学方程,求得反应活化能为77.7 k J?mol?1,约为新鲜吸附剂第一次吸附反应活化能的2.5倍。方程平均相对误差仅为6.4%。得到的改进动力学方程更真实反映吸附剂在稳定循环使用条件下的纳米Ca O与CO2反应动力学特性。     

五乙烯六胺改性制备CO2吸附剂及其对模拟烟气中CO2捕集性能的研究（英文）

A novel solid support adsorbent for CO2 capture was developed by loading pentaethylenehexamine (PEHA) on commercial y available mesoporous molecular sieve MCM-41 using wet impregnation method. MCM-41 sam-ples before and after PEHA loading were characterized by X-ray powder diffraction, N2 adsorption/desorption, thermal gravimetric analysis and scanning electron microscope to investigate the textural and thermo-physical properties. CO2 adsorption performance was evaluated in a fixed bed adsorption system. Results indicated that the structure of MCM-41 was preserved after loading PEHA. Surface area and total pore volume of PEHA loaded MCM-41 decreased with the increase of loading. The working adsorption capacity of CO2 could be significantly improved at 60%of PEHA loading and 75 °C. The effect of the height of adsorbent bed was investigated and the best working adsorption capacity for MCM-41-PEHA-60 reached 165 mg·(g adsorbent)?1 at 75 °C. Adsorption/desorption circle showed that the CO2 working adsorption capacity of MCM-41-PEHA kept stable. ? 2014 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. Al rights reserved.     

流化床反应器中气相丙烯聚合反应的动力学和预测控制(英文)

A two-phase dynamic model, describing gas phase propylene polymerization in a fluidized bed reactor, was used to explore the dynamic behavior and process control of the polypropylene production rate and reactor temperature. The open loop analysis revealed the nonlinear behavior of the polypropylene fluidized bed reactor, jus- tifying the use of an advanced control algorithm for efficient control of the process variables. In this case, a central- ized model predictive control （MPC） technique was implemented to control the polypropylene production rate and reactor temperature by manipulating the catalyst feed rate and cooling water flow rate respectively. The corre- sponding MPC controller was able to track changes in the setpoint smoothly for the reactor temperature and pro- duction rate while the setpoint tracking of the conventional proportional-integral （PI） controller was oscillatory with overshoots and obvious interaction between the reactor temperature and production rate loops. The MPC was able to produce controller moves which not only were well within the specified input constraints for both control vari- ables, but also non-aggressive and sufficiently smooth for practical implementations. Furthermore, the closed loop dynamic simulations indicated that the speed of rejecting the process disturbances for the MPC controller were also acceotable for both controlled variables.     

分散红73和分散蓝183及其混合物在超临界二氧化碳中溶解度的测定与关联(英文)

The solubility of disperse dyes and their mixture in supercritical carbon dioxide is an important property in study and development of supercritical fluid dyeing technology. In this study, solubilities of C.I. Disperse Red 73, C.I. Disperse Blue 183 and their mixture in supercritical CO2 are measured at temperatures from 343.2 to 383.2 K and pressures from 12 to 28 MPa with a static recirculation method. Under the experimental conditions for the binary (C.I. Disperse Red 73 + CO2 or C.I. Disperse Blue 183 + CO2) and ternary (C.I. Disperse Red 73 + C.I. Disperse Blue 183 + CO2) systems, the solubilities increase with pressure. The solubility of C.I. Disperse Blue 183 decreases with the increase of temperature when the pressure is lower than 16 MPa, and the trend is opposite when the pressure is higher than 16 MPa. However, there is no crossover pressure for C.I. Disperse Red 73. The solubilities are also affected by molecular polarity of dyes. The co-solvent effect exhibited in the dissolving process of mixed dyes promotes their disso-lution in supercritical CO2. The experimental data of solubilities of C.I. Disperse Red 73, C.I. Disperse Blue 183, and their mixture are correlated with the Chrastil model and Mendez-Santiago/Teja model. The former is more accurate.     

垂直管式反应器中超临界甲醇连续制备生物柴油I:相含率及反应中间产物的轴向分布(英文)

Production of biodiesel with supercritical methanol is a green synthesis process.A study was carried out in a vertical tubular reactor with a length of 3700 mm and a diameter of 20 mm at 275-375°C,15 MPa,and molar ratio of methanol to soybean oil of 40︰1.The phase holdup,intermediate product,yield and axial distribution of methyl ester(ME) were investigated.Methanol and oil were mixed non-uniformly due to the formation of biodiesel and difference in their densities,even when the reaction system was in the supercritical state.From top to bottom,the phase holdup of methanol increased and that of oil decreased.As temperature increased,the concentrations of monoglyceride and diglyceride decreased gradually and the ME yield increased.When the temperature reached 300°C,the critical temperature of the system,the ME yield was 50%.Further increase in temperature led to a sharp in-crease of ME yield.However,at 375°C after 1200 s of reaction time,the decomposition rate of ME was greater than its formation rate,reducing the ME yield.     

二氧化碳在York地层中埋存的地球化学模拟(英文)

In this paper, we build up a three-dimensional model for CO2 storage in the deep reservoir. And this paper gives the mathematical formalism of combined geochemical and multi-phase flow. The results give us the information about geochemical changing caused by CO2 injection into aqueous, the dissolution or precipitation of reservoir minerals caused by aqueous components change, the change of water density, also the differences between this model and the simulation model without considering geochemical. The basic data for simulation is from York Reservoir.     

CaO/FA吸收剂高温吸收CO2及穿透特性

利用完全煅烧后的CaO和粉煤灰（Fly Ash）为材料制备了CaO/FA吸收剂。在350~650℃温度范围内对其碳酸化反应特性进行了研究。考察了不同质量比的CaO/FA吸收剂吸收CO2的性能。利用XRD、N2吸附等表征手段对吸收剂反应前后产物进行了表征。结果表明：通过水合反应过程,吸收剂比表面积增大,孔径在5~40nm范围内属于中孔,有利于减小CO2向颗粒内部的扩散阻力。CaO/FA吸收剂CO2吸收量随温度的升高而增加。当CaO与粉煤灰的质量比为3:1时制备的吸收剂具有最好的CO2吸收能力,在650℃时其最大CO2吸收量达到了227.13mg/g。通过多次循环试验后,吸附剂仍保持较高的CO2吸收量与稳定吸收性能。失活模型可以很好地预测CaO/FA吸收剂吸收CO2的过程,并得到了理想的吸收速率常数和失活速率常数。     

膜气体吸收法脱除电厂模拟烟气CO_2

介绍了化学吸收法、物理吸收法、吸附法、膜分离法、膜吸收法和低温蒸馏法等烟气减排技术,综述了近几年气体吸收膜法在减少电厂模拟烟气CO2排放中的研究进展及福建省膜研究开发情况,总结了气体吸收膜法发展与应用中存在的不足,指出膜气体吸收法的发展前景。     

CO2 Capture Performance of Calcium‐Based Sorbents in the Presence of SO2 under Pressurized Carbonation

In order to understand the effect of SO₂ on the CO₂ capture performance under pressurized carbonation conditions, tests by orthogonal design were carried out in a calcination/pressurized carbonation reactor system. The effects of variables such as carbonation temperature, carbonation pressure, SO₂ concentration, CO₂ concentration, and the number of cycles on carbonation and sulfation were investigated. A range method was employed for analysis. Phase structure and scanning electron microscopy images were measured as supplement for a reaction study. Temperature increase enhanced the SO₂ capture, leading to a rapid decay in CO₂ uptake. The carbonation pressure had a stronger effect on the CO₂ uptake than the temperature. SO₂ uptake increased rapidly with increasing pressure while CO₂ uptake decreased.     

Modified Photobioreactor for Biofixation of Carbon Dioxide by Chlorella vulgaris at Different Light Intensities

The performance of a modified bioreactor inside a light enclosure for carbon dioxide biofixation by Chlorella vulgaris was investigated. The influence of different light intensities on the CO₂ biofixation and biomass production rates was evaluated. The results showed that the photon flux available to the microalgal cultures can be a key issue in optimizing the microalgae photobioreactor performance, particularly at high cell concentrations. Although the optimal pH values for C. vulgaris are in the range of 6–8, cell growth can take place even at pH 4 and 10. Batch microalgae cultivation in the photobioreactor was used to investigate the effect of different light intensities. The maximum biomass concentration of 1.83 g L^?1 was obtained at a light intensity of 100 μmol m^?2s^?1 and under aeration with 2 L min^?1 of 2 % CO₂‐enriched air.     

利用凹凸棒改性石灰石增强CO2循环捕集效率

石灰石作为天然的CO2吸收剂,可有效的捕集烟气中的CO2,但随着循环反应次数的增加,石灰石颗粒表面会发生严重的烧结,使其酸化率迅速发生衰减.本文中利用自然界储量丰富的凹凸棒石对石灰石颗粒进行改性来减缓这一现象的发生,从而提高其CO2的循环捕集效率.凹凸棒石具有的天然纳米纤维状结构可有效的减少石灰石颗粒之间的相互接触,延缓石灰石的烧结团聚现象,从而提高其碳酸化率.实验结果表明:凹凸棒石原矿和提纯后的凹凸棒石均可作为添加剂提高石灰石对CO2的捕集效率,其中经过提纯处理后的凹凸棒石的改性效果最好;通过比较凹凸棒石改性前后的钙基吸收剂经过多次CO2捕集循环后的颗粒微观形貌的变化,可以发现经过凹凸棒石改性后的石灰石颗粒表面仍留有较多的孔道,使其抗烧结能力得到大幅的提高.     

碳基材料改性石灰石增强其对CO2的捕集效率

在水泥行业中,石灰石不仅是生产水泥的原料,而且也可以用来捕集废气中的CO2.但是,它的捕集效率会因其颗粒表面在经过几次捕集循环后发生烧结而严重降低.在本文中,我们利用不同种类的碳基材料(炭黑、石墨、竹炭和椰壳炭)来改性石灰石,提高其CO2捕集效率.碳基材料的引入可以改变石灰石颗粒的形貌:在煅烧过程中,碳颗粒在CO2的捕集循环前期起到支撑骨架的作用,循环后期碳颗粒在完全燃烧后,会产生孔洞,从而增加石灰石颗粒的比表面积,延缓烧结,提高循环煅烧/碳酸化率.实验研究表明,椰壳碳颗粒改性后的石灰石的CO2捕集效率比纯石灰石提高13％.     

浆态床中二氧化碳加氢合成甲醇

研究了浆态床中自行开发的LP201甲醇合成催化剂上二氧化碳加氢合成甲醇的过程。探讨了不同操作条件,如温度、压力、气体空速、原料气配比等对反应的影响;考察了该催化剂在浆态床二氧化碳加氢合成甲醇过程中的稳定性。实验结果表明,浆态床二氧化碳加氢合成甲醇过程中主要产物为甲醇、CO和水;随温度的增加,CO2的转化率和甲醇产率呈现上升的趋势,但甲醇的选择性明显下降;压力的升高有利于CO2的转化率、甲醇产率以及甲醇的选择性提高;原料气空速的提高会增大甲醇产率,但同时降低CO2的转化率以及甲醇的选择性;CO2的转化率、甲醇收率以及甲醇的选择性在氢碳摩尔比4～5获得极大值。LP201催化剂的寿命考察结果表明,该催化剂具有较好的催化活性和稳定性。     

Reactivity stabilization and capacity study of fabricated alumina and zirconia-supported CaO-based sorbents for high-temperature CO2 capture in a fixed-bed reactor

Calcium looping process is a promising approach for CO₂ capture from the flue gas of fossil fuel power plants and the cement industry. Even though the advantages of calcium-based sorbents are low cost and high uptake capacity, they suffer from low durability during cycles. Modified sorbents were fabricated by adding alumina and zirconia and the mixture of alumina and zirconia to calcium oxide via the co-precipitation method. The performance of synthesized sorbents in terms of stability and CO₂ capture capacity were evaluated using a fixed bed reactor in various CO₂ sorption/desorption cycles. The sorbents were fabricated by a co-precipitation methodology using 10% binders (alumina and/or silica). X-ray diffraction (XRD), BET/BJH, and scanning electron microscopy (SEM) were conducted for characterization of synthesized sorbents. CaO-10% ZrO₂ showed the best performance among the fabricated sorbents in terms of stability during 5 cycles and CO₂ capacity (14 mmol CO₂/g sorbent). The formation of CaZrO₃ with a perovskite structure and high-temperature resistance could be attributed to well performance of zirconia-supported sorbent. On the other hand, no sign of aluminum zirconate formation was approved in XRD analysis for the fabricated sorbent using mixed binders of zirconia and alumina to enhance its stability during cycles.     

Heat Transfer Characteristics of CO2 Desorption from N‐Methyldiethanolamine Solution in a Microchannel Reactor

The heat transfer performance and energy consumption of CO₂ desorption from rich N‐methyldiethanolamine (MDEA) solution were determined experimentally in a straight microchannel reactor. Nucleate boiling was found to be the dominant heat transfer mechanism in this experiment. The heat transfer coefficients were strongly dependent on the heat flux. The solution flow rate was the most influential factor on the heat flux, followed by desorption temperature, MDEA concentration, and CO₂ loading. In addition, an empirical correlation was proposed to predict the experimental heat transfer coefficients.     

Separation of Methane and Carbon Dioxide Gas Mixtures Using Activated Carbon Modified with 2‐Methylimidazole

Activated carbon was modified by loading 2‐methylimidazole (mIm), ethanol, and glycol onto its surface and adopted to capture CO₂ using the absorption‐adsorption method. The modified activated carbon showed high selectivity for separating CH₄+CO₂ gas mixtures, compared with other methods to modify activated carbon given in the literature. The separation factor was 4.75 times higher than that for the fresh activated‐carbon system, and the separation performance of the activated carbon increased with increasing amount of mIm. The addition of glycol showed greater potential to enhance the selectivity of the activated carbon than ethanol. A recycling test verified the stability of the modified activated carbon for CH₄+CO₂ gas mixture separation.