生物质气一步法合成二甲醚化学平衡分析

对生物质基合成气合成二甲醚反应体系进行热力学参数计算.选取CO、CO2加氢合成甲醇及甲醇脱水生成二甲醚为独立反应,CO、CO2、二甲醚为关键组分,提出了合成气合成二甲醚的计算模型.讨论了温度、压力对生物质气合成二甲醚化学平衡的影响.结果表明:CO平衡转化率、DME平衡收率随温度的升高而下降;随压力升高,CO平衡转化率、DME平衡收率增加.     

石灰在旋风收尘器内对HCl气体的中高温净化

实验研究了带直管的旋风收尘器内石灰在450～770℃的中高温对HCl气体的净化效果.研究发现:消石灰自身煅烧反应对吸收效率有较大影响,石灰干式净化效率在650～670℃显示出峰值.烟气中的CO2促使石灰碳酸钙化,削弱了对HCl气体的吸收效果;但改性石灰与普通石灰相比,CO2分压的改变对效率影响较小.随着HCl气体质量浓度和烟气中钙氯当量比的提高,HCI的净化效率提高;但烟气中钙氯比超过4～6以后净化效率不再明显上升.采用带直管的旋风收尘器在合适温度下对HCI气体的净化效率在40%～50%.     

基于反应平衡热力学的转炉炉气分析温度预报模型

炉气分析技术不但可以实现转炉温度连续预测,而且使用年限长.由于不受转炉炉口限制,该技术在不同吨位的转炉上均可应用.本研究根据炉气分析仪实时检测转炉烟气成分,基于反应平衡热力学和对万雪峰模型的修正,建立了转炉实时温度预报模型.修正后的炉气分析模型计算曲线走向稳定,计算值与实测值的误差较小,能真实反映转炉炉内状况.     

高浓度CO_2下CaCO_3循环煅烧试验与模拟

建立了高浓度CO2气氛下CaCO3循环煅烧过程数学模型,利用钙基吸收剂多次循环煅烧试验对模型进行了验证,在此基础上分析了CO2浓度、吸收剂种类、粒径和循环次数等参数对CaCO3煅烧的影响。结果表明:CaCO3分解温度随气相中CO2含量的增加而增大;在高浓度CO2下,随循环反应次数的增加,吸收剂循环反应活性下降,使得所生成的CaCO3质量也随循环次数的增加而减少,致使CaCO3煅烧完全所需时间会随循环反应次数的增加而减少。     

垃圾和污泥共燃过程中重金属的赋存迁移规律

采用热力学平衡计算方法,研究了垃圾和污泥焚烧过程Cu、Mn、Zn重金属的迁移规律,考察了温度、HCL、S以及焚烧中污泥水分高低对重金属迁移特性的影响.研究结果表明:除焚烧温度外,HCl是影响重金属迁移的主要因素,HCl的存在会促进难挥发重金属(Cu、Zn)低温时就挥发出来;污泥含水率的降低会增加氯化锌的挥发量,但影响较小,含水率由72％降至12％,氯化锌百分含量增加不到5％.     

循环流化床烟气脱硫中物料平衡计算及试验研究

通过对干法烟气脱硫物料平衡计算,确定脱硫塔内固体颗粒物平衡浓度和达到平衡浓度所需要的时间, 并和实测值加以比较．在一台循环流化床烟气脱硫装置上,研究了固体颗粒物浓度对装置脱硫效率影响、阻力特性以及固体颗粒物循环对脱硫装置稳定运行的影响．结果表明,固体颗粒物的循环可以使脱硫效率提高10％-15％, 脱硫系统物料循环平衡的时间大约为30 min．综合实验结果,循环流化床烟气脱硫塔内固体颗粒物浓度宜控制在 600-1 000 g／m3之间．     

高压水洗沼气净化吸收塔的模拟研究

运用Aspen Plus软件对沼气高压水洗净化工艺中的吸收塔进行了模拟计算。选用RadFrac单元操作模型,采用NRTL热力学性质计算方法,对吸收塔的填料高度和吸收剂用量进行了初步设计,在一定操作条件下考察了塔顶、塔底组成和塔内流量、温度及组成分布的情况、吸收过程中压强、吸收剂用量及吸收塔填料高度对净化后生物甲烷纯度的影响。模拟数据对实际应用具有指导意义。     

瞬态工况下 EGR 率测量方法的研究

稳态工况EGR率的测量通常采用测量CO2浓度的方法，在瞬态工况下CO2分析仪存在响应滞后的问题，提出利用热力学能量守恒原理，通过测量EGR混合前后的气体温度，计算出基于质量比率的EGR率，并对测量精度进行了分析，与目前国内外通用的测量CO2的浓度来计算EGR的方法进行了比较。温度法测量的EGR率基本上可以满足瞬态下EGR率的测量要求。     

耦合详细/半详细反应动力学机理的碳氢燃料预混气着火过程及火焰结构数值预测

理论分析碳氢类燃料、空气预混气热着火和流动燃烧过程数值计算方法.并对IPIC -CFDⅡ软件进行修改,使之适合燃料零维着火与火焰结构计算.程序采用了美国SANDLA国家实验室、NASA和BERKELEY大学热力学数据库中的相关参数以及大型化学反应动力学软件包CHEMKIN中相关的模型和子程序;火焰结构计算模块引入美国SANDLA国家实验室开发的PREMIX程序.运用开发的源码,以庚烷/空气预混气和碳氢类燃料中具有代表性的柴油为例采用最新的化学反应动力学机理(其中庚烷氧化机理包含290个基元反应,涉及57种组分;柴油动力学机理包含327个基元反应,涉及71种组分),计算了C7H16/O2/N2预混气在不同点火温度、不同当量比和不同压力下的着火延迟时间,预测了火焰中反应物、主产物、自由基浓度以及温度变化的时间进程;同时模拟了柴油在不同工况下,其预混火焰中温度、反应物、主产物和自由基浓度随火焰高度的变化关系.以上研究为反应设计提供指导.     

填料塔中碳酸丙烯酯脱除沼气中的CO_2

以木薯渣发酵产生的沼气为原料气,采用10 m3/d脱碳工艺试验装置,以碳酸丙烯酯为吸收剂脱除沼气中的CO2,分别考察了吸收气液比、吸收压力、吸收温度、空气气提气液比、原料沼气中硫化氢浓度对脱碳效果的影响。试验结果表明,吸收气液比为55、吸收压力为800 kPa、吸收温度15℃、空气气提气液比为10时,净化气中CO2浓度为(6.44±0.34)%,CO2脱除率为(92.48±0.39)%。原料沼气中H2S浓度对碳酸丙烯酯的脱碳效果影响显著,当H2S浓度增加到0.4%时,与以脱硫后沼气为原料气时的脱碳情况相比,净化气中CO2浓度增加了1.66%。     

废弃物焚烧炉烟气中HCl的脱除

介绍了废弃物焚烧烟气中HCl气体的生成机理及各种脱除方法，并对各种方法的适用场合进行了分析，指出了发展方向。根据我国废弃物的组成特点，推荐了适用且比较简单的干式系统，并进一步介绍了提高干式系统吸收效率的几种方法，重点对作者在研究的通过添加一定量的碱性行质对吸收剂进行改性来提高吸收效率的方法作了介绍。     

HCl Dry Removal with Modified Ca-Based Sorbents at Moderate to High Temperatures

Modified Ca-based sorbents were obtained by adding sodium alkali into Ca(OH)2 and CaCO3. Reactive properties of modified Ca-based sorbents with acidic gases were investigated through reacting with gaseous HC1 at 450-760℃, and SEM and XRD technologies were adopted to get information on the reaction mechanism. Experimental data showed that HC1 dry removal efficiencies increased with temperature before 700℃ for all of the investigated sorbents, and there existed improved sorbents that corresponded to the highest removal efficiencies under the similar conditions. SEM photographs exhibited morphology difference between original and improved sorbents both before and after the reaction; and displayed that improved sorbents formed more porous product layers than original sorbents especially at higher temperature when product sintering became heavier, which is favorable to HC1 dry removal. XRD analysis showed that (1) improved Ca(OH)2 and CaCO3 were less crystalline than original lime and limestone; (2) the re     

城市垃圾焚烧HCI排放与脱除试验研究

HCl是城市垃圾焚烧产生的主要气体污染物之一。有机氯废物以聚好乙烯为试样,无机含氯废物以含NaCl的煤浆为试样,研究了焚烧过程中反应温度对HCl排放的影响,还研究了各碱基吸收剂、吸收剂颗粒尺寸、钙氯比等因素对HCl脱除效率的影响。     

CO2 capture efficiency and energy requirement analysis of power plant using modified calcium-based sorbent looping cycle

This paper examines the average carbonation conversion, CO₂ capture efficiency and energy requirement for post-combustion CO₂ capture system during the modified calcium-based sorbent looping cycle. The limestone modified with acetic acid solution, i.e. calcium acetate is taken as an example of the modified calcium-based sorbents. The modified limestone exhibits much higher average carbonation conversion than the natural sorbent under the same condition. The CO₂ capture efficiency increases with the sorbent flow ratios. Compared with the natural limestone, much less makeup mass flow of the recycled and the fresh sorbent is needed for the system when using the modified limestone at the same CO₂ capture efficiency. Achieving 0.95 of CO₂ capture efficiency without sulfation, 272 kJ/mol CO₂ is required in the calciner for the natural limestone, whereas only 223 kJ/mol CO₂ for the modified sorbent. The modified limestone possesses greater advantages in CO₂ capture efficiency and energy consumption than the natural sorbent. When the sulfation and carbonation of the sorbents take place simultaneously, more energy is required. It is significantly necessary to remove SO₂ from the flue gas before it enters the carbonator in order to reduce energy consumption in the calciner.     

Development and evaluation of magnetic iron-carbon sorbents for mercury removal in coal combustion flue gas

In order to get a cost effective and recyclable sorbent for mercury removal, a series of magnetic iron-carbon (Fe–C-x) sorbents was developed by co-precipitation. The physical and chemical properties of obtained sorbents were evaluated through various characterization methods. According to the results, Fe₃O₄ precipitate on carbon weakens the surface properties, but mercury removal performance in simulated flue gas is excellent. For flue gas components, HCl promotes mercury oxidation and adsorption on sorbents, O₂ has limited effect on mercury removal and SO₂ plays an inhibitive role. NO could enhance mercury oxidation with O₂ existence because of the generation of NO₂, which could react with Hg⁰ through heterogeneous reaction over iron-carbon surface. Besides, effects of temperature and regeneration performance were further researched under simulated flue gas. Apart from higher temperature will decompose mercury compounds and cause the removal efficiency decrease, Fe–C-3 sorbent shows excellent Hg⁰ removal performance at the temperature window of 100–200 °C. Exceptional regeneration performance on Hg⁰ removal indicates that spent sorbent could be regenerated.     

烟煤掺烧污泥HCl的排放和脱除实验研究

污泥与煤混烧发电是一种较有发展前景的污泥处理方法,而混烧过程中产生的大量HCl气体会造成受热面腐蚀等危害。利用水平管式反应炉研究了升温速率、燃烧温度、污泥掺混比例以及反应气氛等因素对HCl释放的影响,考察了CaCO3添加量和添加温度对HCl脱除效果,并利用GAS-MET DX4000型红外气体分析仪实时测定HCl释放浓度。结果表明:随着污泥掺烧比例增加,HCl释放体积增加,而Cl→HCl转化率降低;温度升高会促进HCl释放,但600℃后Cl→HCl转化率变化不大;载气中氧气比例升高使得部分HCl转化为Cl2,导致样品中Cl→HCl转化率降低;高升温速率导致HCl释放峰值变大;Ca/(S+0.5Cl)摩尔比增大,则HCl脱除率增加,且Ca/(S+0.5Cl)摩尔比为2时,700℃是HCl脱除最佳温度。     

燃煤烟气脱汞吸附剂研究进展

概述了目前当今世界燃煤烟气中脱汞吸附剂的研究现状,介绍了碳基吸附剂、钙基吸附剂、石油焦、飞灰,以及一些新型吸附剂对汞的脱除效果。指出活性炭对汞的脱除效率高,但成本也高;飞灰吸附剂对汞脱除的成本低,但脱除效率也低。用于燃煤电厂汞吸附的吸附剂研究处于实验室研究阶段,因此开发价廉和高效脱汞吸附剂和吸附剂的再生等是吸附剂发展过程中的一个重要研究课题。     

Investigation on elemental mercury removal by cerium modified semi-coke

Coal-fired power plant is the largest anthropogenic mercury source. Active carbon injection technique has been widely used to control the mercury emissions. However, high operation cost limits its development and it is necessary to find other potential mercury sorbents. In this study, raw semi-coke and a series of novel cerium (Ce) modified semi-cokes were synthesized and utilized for removing elemental mercury (Hg⁰) from simulated flue gas. It is noteworthy that the efficiencies were tested without hydrogen chloride (HCl) in order to evaluate the sorbents efficacy for low-chlorine (Cl) coal. The results show that the modified sorbents exhibited the best performance at 150 °C. The performance of sorbent could be reinforced due to the existence of oxygen (O₂), nitric oxide (NO) and HCl. The adverse effect caused by sulfur dioxide (SO₂) reduced dramatically after Ce modification. The negative impact of ammonia (NH₃) on Hg⁰ removal in this study could be neglected owing to the tiny concentration of NH₃. Raw semi-coke provided sufficient carbon content, which is favorable to mercury adsorption. As Ce loading increased, the carbon structure changed and the crystal of cerium oxide was formed in the modified semi-coke. The mass fraction of cerium oxide on the sorbent was over 4.4% when the concentration of Ce modification solution was higher than 0.2 mol L⁻¹. The redox reaction activity and the oxygen storage ability of Ce³⁺/Ce⁴⁺ gave a huge boost to the performance of modified semi-coke. The addition of Ce also had an impact on the proportion of oxygen species.     

The kinetics and mechanism of alkali removal from flue gases by solid sorbents

Kaolinite, bauxite and emathlite have been found suitable for alkali removal from hot flue gases in coal conversion systems. The effect of temperature on the kinetics and mechanism of alkali adsorption/reaction on these sorbents was studied under a simulated flue gas atmosphere. Kaolinite and emathlite reacted irreversibly with the alkali; however for bauxite, 10% of the total weight gained was due to physisorption. Kaolinite was found to have the highest capacity and the largest activation energy for alkali removal. The overall sorption process is not just physical and non-selective, but rather a combination of physical and chemical processes, which are dependent on the temperature and sorbent chemistry. The reaction product of alkali with emathlite has a melting point of approximately 1270 K, while kaolinite and bauxite form compounds with a melting point of about 1870 K. Consequently, kaolinite and bauxite are more suitable for in situ removal of alkali, while all three can be used for downstream alkali removal.     

Chemical hot gas cleaning concept for the “CHRISGAS” process

The aim of the CHRISGAS project was the development of a gasification technique to produce clean hydrogen-rich synthesis gas from biomass. In order to improve the process efficiency, this work presents a gas cleaning concept, which combines chemical hot gas cleaning with hot (1 MPa, 900 °C) and warm (1 MPa, 300 °C) filtration. As the focus is set on the removal of H₂S, HCl and KCl, calculations on chemical gas cleaning for the hot and warm gas filter were done using a thermodynamic process model using SimuSage? (GTT-Technologies). The calculations show that Ca-based and Fe-based sorbents are not suitable H₂S sorbents under the conditions of the hot gas filter. For Cu-based sorbents, H₂S concentration below 100 cm³ m^?3 is achievable, if the temperature is reduced below 810 °C. Additional calculations of KCl sorption on alumosilicates under the conditions of the hot gas filter show that the alkali concentration in gasifier-derived gases can be limited to 100 mm³ m^?3. Thus, the condensation temperature of KCl can be decreased down to 580 °C. The results of HCl sorption calculations show that Na- and K-based sorbents are only suitable for temperatures below 600 °C. Therefore, the HCl sorption is transferred to the warm gas filter. The KCl sorption results were confirmed by experiments using bauxite, bentonite, kaolinite and naturally occurring zeolite as sorbents.