合成氨尿素装置减排CO2节能创新工艺发展前景

本文主要从合成氨尿素装置减排二氧化碳的方式开展了一定的探讨,根据合成氨尿素装置的改造、创新工艺的应用与发展等方面进行了探究,并对该工艺的发展现状以及前景进行了一定的分析,从而为有效减少二氧化碳在合成氨尿素工艺中的排放量提供借鉴。     

CO2规模化回收利用及研究进展

通过介绍全球及中国近年来CO2的排放状况以及小规模回收技术的缺陷,首先指出了CO2规模化回收的迫切性及资源化利用的优势,并以CCS(碳捕集与封存)和CCU(碳捕集与利用)为例,分别介绍了诸如地质封存、海洋封存、化学转化和生物转化等规模化回收利用技术,阐述了这些技术的回收原理、工艺路线、安全环保性、技术优势和工业化案例;通过分析CCS各技术的封存能力、封存效果、技术瓶颈及工业化推广的进度和潜力,指出CCS技术的全球化应用目前还存在一定的风险和制约;通过对比CCU各技术研究重点、转化瓶颈以及工业化进度等,指出化学转化法是目前最有效的CO2规模化回收利用技术。最后还介绍了其他几种具有规模化潜力的CO2利用新技术。     

CO2的化学性处理技术

工业的发展加剧了CO2的排放量,过量的排放威胁着人类的生存,近年来人们对CO2的吸收技术尤为重视,本文详细阐述了CO2的化学吸收技术及工艺,提出了目前该技术发展中存在的障碍,并指出未来二氧化碳控制技术中化学吸收法的发展方向。     

水泥行业CO2排放特征及治理技术研究

本文系统梳理分析了水泥不同种类和各工序的CO₂排放特征,其中,工艺、燃料直接CO₂排放占比达90%,与物料中碳酸盐的含量正相关,与燃料发热量和利用率负相关,电力间接CO₂排放占比约10%,特种水泥由于减少了碳酸盐分解造成的碳排放,总体碳排放量较低。新型干法水泥生产过程可分为生料制备、熟料煅烧和水泥粉磨三个阶段,工艺和燃料CO₂排放主要发生在熟料煅烧阶段,其尾气中CO₂浓度一般在11%～29%。研究分析了碳替代/碳捕集等控碳技术、CO₂资源化利用技术。水泥厂碳替代主要是原料替代、熟料或水泥替代、燃料替代等,可分别实现减碳10%、25%～50%和30%以上;碳捕集主要有富氧燃烧和烟气CO₂捕集,水泥窑富氧燃烧技术有全氧燃烧和分解炉全氧燃烧技术两种。捕集技术主要采用化学吸收法、固体吸附法;在CO₂综合利用方面,针对水泥厂的特殊应用场景,矿化具有较好的应用效果,如采用混凝土养护技术,制备高附加值的微纳米碳酸钙等。     

微藻光合减排燃煤电厂烟气CO2及资源化利用研究进展

微藻光合作用固定燃煤发电厂烟气CO₂及其生物质能源化资源化利用已成为低碳循环的核心技术,是实现我国“双碳”目标有效途径之一。然而烟气中CO₂浓度高(相对自然界藻类生长的空气氛围),且存在易溶酸性气体,如SO₂等,对微藻光合生长及碳转化过程是极大挑战,造成我国微藻捕集烟气CO₂的工程应用非常有限。为促进微藻固定烟气CO₂发展,针对烟气高浓度CO₂和含SO₂等酸性气体的特点,从耐受烟气氛围的高效藻种构建、微藻对高浓度碳的代谢及转化过程调控再到烟气中高浓度CO₂在光生物反应器中的传输及转化过程进行全面综述。小球藻是最有望实现微藻生物固定烟气CO₂的藻种。通过筛选和驯化等方式,小球藻可适应烟气的高碳浓度和一定浓度下酸性气体的胁迫,并保持较高固碳速率。烟气在光生物反应器内溶解传输及引起多相流动是影响微藻固碳性能的关键,强化反应器内的CO₂传输并抑制SO₂酸性...     

耦合绿电煤气化生产化学品过程CO2减排潜力

耦合可再生能源生产的绿电为煤气化反应供热以消除燃烧供热实现自热平衡的影响,不仅可有效降低气化过程CO₂排放量,还能提高合成气氢碳比(H/C),从而降低以煤气化为源头生产化学品的水煤气变换工段中CO₂排放。对不同类型的常规气化反应器和相应的耦合绿电反应器进行建模与模拟,判明合成气组分的主要影响因素,分析了温度对合成气组分的影响,探讨合成气H/C随温度变化规律,并计算不同化学品生产过程的CO₂减排潜力。结果表明,耦合绿电的气化反应器合成气中CO₂排放较常规气化反应器分别减少了12.63%(固定床)、11.01%(气流床)、9.23%(输运床)和5.12%(流化床),且H/C呈上升趋势;温度对合成气组分影响较大,热解解耦和气化反应的反应器一定程度上影响合成气组分;温度低于1 500 K时,H/C随温度升高而降低;温度高于1 500 K时,H/C随温度升高而缓慢升高;耦合绿电煤基化学品生产过程CO₂排放大幅减少,操作在更低温度和压力的气化反应器具有更高的合成气H/C和CO_2<...     

CO2汽提法尿素装置解吸废液减排技改小结

安徽六国化工股份有限公司300 kt/a CO₂汽提法尿素装置每生产1 t尿素产生约0.60 t的氨水,需在解吸水解系统中处理成NH₃含量<5×10^-6、尿素含量<5×10^-6的合格废液排出。传统尿素装置氨水处理采用外来加热蒸汽直接加入解吸塔底部的方法,加热蒸汽冷凝液与解吸废液混合在一起造成解吸废液排放量大、蒸汽冷凝液难以回收利用等弊端。为此,六国化工对尿素解吸水解系统进行了解吸废液减排技改——在第二解吸塔底部外置蒸汽发生器,部分解吸废液经蒸汽发生器壳侧中压蒸汽间接加热产生二次蒸汽以加热第二解吸塔塔底解吸废液,中压蒸汽冷凝液则回收至蒸汽冷凝液系统循环利用,由此实现了降低解吸废液排放量、减轻企业环保压力、无污染高品质蒸汽冷凝液回收利用的目标,有力地推动了尿素装置的节能减排。     

CO2气体分离技术研究进展

简要介绍工业上所采用的CO2分离技术,重点介绍了各种CO2分离技术(包括研发阶段的分离技术)的特点及适用范围,并对各种方法进行了比较。     

基于STEP7的加热炉燃烧系统CO2减排技术研究与应用

针对目前CO₂减排技术存在的减排效果较差的问题,提出了一种基于STEP7的加热炉燃烧系统CO₂减排技术。介绍了加热炉燃烧系统的结构,分析了常规CO₂减排流程在变量复杂度方面存在的不足,引入了化学吸收法优化减排效率,并建立了应用有机醇胺的CO₂吸收模型。实际测试结果表明：该方法具有较好的减排性能,CO₂吸收速率高、减排负荷低、CO₂能源再生效果好。     

热助光催化CO2还原研究进展与展望

光热催化是一种极具前途的CO₂还原策略,可利用太阳光谱的广泛吸收来激发热化学和光化学过程的结合,从而协同推动催化反应的进行,使CO₂在较为温和的条件下实现高效转换。作为光热催化的一种,在光催化中引入热能,可提高太阳光利用率,促进载流子的激发和分离,加快反应分子扩散,提升反升性能。对当前光热催化CO₂还原的概念和原理进行分类,并对热助光催化还原CO₂反应的研究现状进行总结。基于反应产物的差异,介绍热助光催化反应的催化剂选择、反应条件和反应机理,同时介绍了该类反应试验过程中关键的局部测温技术,最后对热助光催化CO₂还原技术的发展进行了展望,未来的研究重点应是提升CO₂转化率和产物选择性,同时利用先进的原位表征技术和理论计算对反应机理进行探究。     

CO2——21世纪的新碳源

本文对21世纪的一种新碳源CO     

Adsorption of CO2 from dry gases on MCM-41 silica at ambient temperature and high pressure. 2: Adsorption of CO2/N2, CO2/CH4 and CO2/H2 binary mixtures

Adsorption equilibrium capacity of CO₂, CH₄, N₂, H₂ and O₂ on periodic mesoporous MCM-41 silica was measured gravimetrically at room temperature and pressure up to 25 bar. The ideal adsorption solution theory (IAST) was validated and used for the prediction of CO₂/N₂, CO₂/CH₄, CO₂/H₂ binary mixture adsorption equilibria on MCM-41 using single components adsorption data. In all cases, MCM-41 showed preferential CO₂ adsorption in comparison to the other gases, in agreement with CO₂/N₂, CO₂/CH₄, CO₂/H₂ selectivity determined using IAST. In comparison to well known benchmark CO₂ adsorbents like activated carbons, zeolites and metal-organic frameworks (MOFs), MCM-41 showed good CO₂ separation performances from CO₂/N₂, CO₂/CH₄ and CO₂/H₂ binary mixtures at high pressure, via pressure swing adsorption by utilizing a medium pressure desorption process (PSA-H/M). The working CO₂ capacity of MCM-41 in the aforementioned binary mixtures using PSA-H/M is generally higher than 13X zeolite and comparable to different activated carbons.     

山西省实施CO2捕集与封存技术前景展望

针对山西省资源禀赋、地理特征、能源消费结构和污染状况,结合CO2捕集与封存技术(CCS)发展现状,分析了山西省CO2排放源及封存区状况,指出在山西省实施CO2捕集与封存技术潜力巨大,应用前景广阔,对于碳减排和应对气候变化具有重要意义,提出通过政策及法律法规建设、资金及人才储备、合作机制建设、示范项目建设等来进一步推动山西实施CO2捕集与封存技术。     

Enhanced gas production and CO2 storage in hydrate-bearing sediments via pre-depressurization and rapid CO2 injection

Carbon emission reduction and clean energy development are urgent demands for mankind in the coming decades.Exploring an efficient CO₂ storage method can significantly reduce CO₂ emissions in the short term.In this study,we attempted to construct sediment samples with different residual CH₄ hydrate amounts and reservoir conditions,and then investigate the potentials of both CO₂ storage and enhanced CH₄ recovery in depleted gas hydrate deposits in the permafrost and ocean zones,respectively.The results demonstrate that CO₂ hydrate formation rate can be significantly improved due to the presence of residual hydrate seeds;However,excessive residual hydrates in turn lead to the decrease in CO₂ storage efficiency.Affected by the T-P conditions of the reservoir,the storage amount of liquid CO₂can reach 8 times that of gaseous CO₂,and CO₂ stored in hydrate form reaches 2-4 times.Additionally,we noticed two other advantages of this method.One is that CO₂ injection can enhance CH₄ recovery rate and increases CH₄ recovery by 10%-20%.The second is that hydrate saturation in the reservoir can be restored to 20%-40%,which means that the solid volume of the reservoir avoids serious shrinkage.Obviously,this is crucial for protecting the goaf stability.In summary,this approach is greatly promising for high-efficient CO₂ storage and safe exploitation of gas hydrate.     

Simultaneous easy CO2 recovery and drastic reduction of SOx and NOx in O2/CO2 coal combustion with heat recirculation

Coal combustion with O₂/CO₂ is promising because of its easy CO₂ recovery, extremely low NO_x emission and high desulfurization efficiency. Based on our own fundamental experimental data combined with a sophisticated data analysis, its characteristics were investigated. It was revealed that the conversion ratio from fuel-N to exhausted NO in O₂/CO₂ pulverized coal combustion was only about one fourth of conventional pulverized coal combustion. To decrease exhausted NO further and realize simultaneous easy CO₂ recovery and drastic reduction of SO_x and NO_x, a new scheme, i.e. O₂/CO₂ coal combustion with heat recirculation, was proposed. It was clarified that in O₂/CO₂ coal combustion, with about 40% of heat recirculation, the same coal combustion intensity as that of coal combustion in air could be realized even at an O₂ concentration of as low as 15%. Thus exhausted NO could be decreased further into only one seventh of conventional coal combustion. Simultaneous easy CO₂ recovery and drastic reduction of SO_x and NO_x could be realized with this new scheme.     

Modeling char conversion under suspension fired conditions in O2/N2 and O2/CO2 atmospheres

The aim of this investigation has been to model combustion under suspension fired conditions in O₂/N₂ and O₂/CO₂ mixtures. Experiments used for model validation have been carried out in an electrically heated Entrained Flow Reactor (EFR) at temperatures between 1173 K and 1673 K with inlet O₂ concentrations between 5 and 28 vol.%. The COal COmbustion MOdel, COCOMO, includes the three char morphologies: cenospheric char, network char and dense char each divided between six discrete particle sizes. Both combustion and gasification with CO₂ are accounted for and reaction rates include thermal char deactivation, which was found to be important for combustion at high reactor temperatures and high O₂ concentrations. COCOMO show in general good agreement with experimental char conversion profiles at conditions covering zone I-III. From the experimental profiles no effect of CO₂ gasification on char conversion has been found. COCOMO does however suggest that CO₂ gasification in oxy-fuel combustion at low O₂ concentrations can account for as much as 70% of the overall char consumption rate during combustion in zone III.     

CO2甲烷化研究进展

CO_2是造成温室效应的主要气体,作为碳基能源使用的末端形态,CO_2也是种重要的基础碳源。因此,将CO_2转化为能源产品可以快速实现碳的循环,对环境与能源领域意义重大。介绍了CO_2的排放、回收以及资源化利用现状,从催化剂体系、反应机理、合成工艺以及工业化现状等方面系统地介绍了CO_2甲烷化的发展。针对H2供给对CO_2甲烷化应用的限制,分析了电解水制氢再与CO_2进行甲烷化反应的电制气(Pt G)技术的发展现状、工艺路线及其经济性,讨论了该技术在我国应用的可行性。提出随着CO_2捕集与新能源相关技术的发展,Pt G技术会更加成熟,将有望成为未来CO_2资源化利用的重要形式。