基于FTIR分析的稻草热解机理

The pyrolysis mechanism of rice straw (RS) was investigated using a tube reactor with Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analyzer. The results show that the maximum pyrolysis rate increases with increasing heating rate and the corresponding temperature also increases. The three-pseudocomponent model could describe the pyrolysis behavior of rice straw accurately. The main pyrolysis gas products are H2O, CO2, CO, CH4, HCHO (formaldehyde), HCOOH (formic acid), CH3OH (methanol), C6H5OH (phenol), etc. The releasing of H2O, CO2, CO and CH4 mainly focuses at 220-400°C. The H2O formation process is separated into two stages corresponding to the evaporation of free water and the formation of primary volatiles. The release of CO2 first increases with increasing temperature and gets the maximum at 309°C. The releasing behavior of CO is similar to H2O and CO2 between 200 and 400°C. The production of CH4 happens, compared to CO2 and CO, at higher temperatures of 275-400°C with the maximum at 309°C. When the temperature exceeds 200°C, hydroxyl and aliphatic C H groups decrease significantly, while C O, olefinic C C bonds and ether structures increase first in the chars and then the aromatic structure develops with rising temperature. Above 500°C, the material becomes increasingly more aromatic and the ether groups decreases with an increase of temperature. The aromatization process starts at ≈350°C and continues to higher temperatures.     

Al4C3 Hydration Thermochemical Analysis for Burned Carbon-Containing Refractories with Al

In this paper,X-ray diffractogram analysis and SEM observation of Al4C3 formed at high temperature from carbon-containing refractories with Al have been carried out.Aluminum added to carbon-containing refractories reacts with C(s) to form Al4C3(s) gradually during heating from 600℃ to 1200℃，It is considered that the interlocked structure of Al4C3 plate crystals promotes the outstanding increase of hot modulus of rupture of carbon-containing refractories with Al.The HMOR of carbon-contatining refractories with Al.The HMOR of carbon-containing refractories added with Al additive from 0 to 5wt% increases by 2.8 times being from 6.5MPa to 18.2MPa.After a thermochemical Calculation for hydration reaction Processes of Al4C3 and H2O(g),the equilibrium partial pressure chart of H2O(2)in H2O-Al4C3-Al(OH)3 system vs various temperatures has been attained.The H2O(g) partial pressure in the air needed for the Al4C3 hydration reaction is no more than 10-18 atm at the temperature below 120℃。It is considered that the temperature below 120℃. It is considered that the burned carbon-containing refractories with Al is extremely easy to hydrate and the cracking of buurned carbon-containing refractories is generated because that the hydration expansion is 2.11 times during transforming from Al4C3 to Al(OH)3.The fundamental measure against hydration of the refractories is to insulate the refractories from H2O(g) by various means such as pitch impregnatiion or other sealing materials.     

CH4、CO2及CH4+C2H6+C3H8在纯水、SDS水溶液和含石英砂体系中水合物相平衡条件的测定

Phase equilibrium conditions of gas hydrate in several systems were measured by the step-heating method using the cylindrical transparent sapphire cell device. The experimental data for pure CH4 or CO2 + deionized water systems showed good agreement with those in the literatures. This kind of method was then applied to CH4/CO2 + sodium dodecyl sulfate (SDS) aqueous solution, CH4/CO2 + SDS aqueous solution + silica sand, and (CH4 + C2H6 + C3H8) gas mixture + SDS aqueous solution systems, where SDS was added to increase the hydrate formation rate without evident influence on the equilibrium conditions. The feasibility and reliability of the step-heating method, especially for porous media systems and gas mixtures systems were determined. The experimental data for CO2 + silica sand data shows that the equilibrium pressure will change significantly when the particle size of silica sand is less than 96 μm. The formation equilibrium pressure was also measured by the reformation of hydrate.     

Performance characteristics of fluidized bed syngas methanation over Ni-Mg/Al2O3 catalyst

The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized bed reactor it was clarified that the CO conversion varied in 5% when changing the space velocity in 40–120 L·g?1·h?1 but the conversion increased obviously by raising the superficial gas velocity from 4 to 12.4 cm·s?1. The temperature at 823 K is suitable for syngas methanation while obvious deposition of uneasy-oxidizing Cγoccurs on the catalyst at temperatures around 873 K. From a kinetic aspect, the lowest reaction temperature is suggested to be 750 K when the space velocity is 60 L·g?1·h?1. Raising the H2/CO ratio of the syngas increased proportionally the CO conversion and CH4 selectivity, showing that at enough high H2/CO ratios the active sites on the catalyst are sufficient for CO adsorption and in turn the reaction with H2 for forming CH4. Introducing CO2 into the syngas feed suppresses the water gas shift and Boudouard reactions and thus increased H2 consumption. The ratio of CO2/CO in syngas should be better below 0.52 because varying the ratio from 0.52 to 0.92 resulted in negligible increases in the H2 conversion and CH4 selectivity but decreased the CH4 yield. Introducing steam into the feed gas affected little the CO conversion but decreased the selectivity to CH4. The tested Ni–Mg/Al2O3 catalyst manifested good stability in structure and activity even in syngas containing water vapor.     

采用数值模拟方法研究同时氧化烟气中NO和SO2的可行性添加剂

Mechanism analysis on simultaneous oxidation of NO and SO2 with additives was presented and numerical simulation was developed to investigate the performances of three additives on oxidation of NO and SO2. The simulation result showed that reaction temperature, residence time, additive dose and NO concentration influence the oxidation process significantly. There exists an optimum reaction condition for each additive, n-C4H10 has the strongest ability to oxidize NO and SO2.     

1,6-二磷酸果糖三钠盐·8H2O结晶新方法的研究

In order to overcome the elementary heterogeneous nucleation while octahydro trisodium salt of fructose-1,6-diphosphate(FDPNa3 8H2O) is crystallized with ethanol precipitation at low temperature, a new crystallization method with alcohol precipitation combined with salt precipitation has been presented. The ethanol-sodium acetate system for crystallization of salt of fructose-1,6-diphosphate is based on the mechanism of crystallization of FDPNa3 8H2O in the ethanol-low temperature system. It is found that crystal size may be controlled by regulating temperature or pH value of solution in the crystallization process, and the crystal yield increases to 95% from 78% which obtained in the ethanol-low temperature system.     

Effect of endogenous hydrogen utilization on improved methane production in an integrated microbial electrolysis cell and anaerobic digestion: Employing catalyzed stainless steel mesh cathode

Improving the production of methane,while maintaining a significant level of process stability,is the main challenge in the anaerobic digestion process.Recently,microbial electrolysis cell (MEC) has become a promising method for CO2 reduction produced during anaerobic digestion (AD) and leads to minimize the cost of biogas upgrading technology.In this study,the MEC-AD coupled reactor was used to generate and utilize the endogenous hydrogen by employing biocompatible electrodeposited cobalt-phosphate as catalysts to improve the performance of stainless steel mesh and carbon cloth electrodes.In addition,the modified version of ADM1 model (ADM1da) was used to simulate the process.The result indicated that the MEC-AD coupled reactor can improve the CH4 yield and production rate significantly.The CH4 yield was enhanced with an average of 48％ higher than the control.The CH4 production rate was also increased 1.65 times due to the utilization of endogenous hydrogen.The specific yield,flow rate,content of CH4,and pH value were the variables that the model was best at predicting (with indexes of agreement:0.960/0.941,0.682/0.696,0.881/0.865,and 0.764/0.743) of the process with SS-meshes 80/SS-meshes 200,respectively.Employing the catalyzed SS mesh cathode,in the MEC-AD coupled reactor,could be an effective approach to generate and facilitate the utilization of endogenous hydrogen in anaerobic digestion of CH4 production technology,which is a promising and feasible method to scale up to the industrial level.     

气体透过碳膜的非平衡动力学模拟研究

The permeation of various pure gas （H2, He, Ne, CH4 and At） through carbon membranes is investigated using a dual control volume grand canonical molecular dynamics method. A two-dimensional slit pore is employed instead of the one-dimensional pore. Compared with the experiments, simulation results show that the improvement of pore model is very necessary. The effects of membrane thickness, pore width and temperature on gas permeance and ideal separation factor are also discussed. Results show that gas permeates through membrane according to Knudsen diffusion in large pore, while Knudsen diffusion is accompanied by molecular sieving in small pore. Moreover, methane is easily adsorbed on the membrane surface due to strong attractive interactions of membrane and shows higher permeance than that of Knudsen flow. In addition, it is noted that when membrane thickness is thin enough the permeance of gas does not decrease with the increase of membrane thickness due to the strong adsorption until membrane resistance becomes dominant.     

Permeation properties of CO2and CH4in asymmetric polyethersulfone/polyesterurethane and polyethersulfone/polyetherurethane blend membranes

The transport performances of carbon dioxide and methane were studied in polyethersulfone,polyethersulfone/polyeterurethane (PES-ETPU) and polyethersulfone/polyestherurethane (PES-ESPU) blend membranes separately with different compositions.The variations in the structural characteristics of PES membrane after incorporation of ESPU and ETPU were investigated by different techniques.Additionally,the effect of pressure and composition on the permeance of CO2,CH4and ideal selectivity of CO2/CH4were checked on the membranes. The results revealed that the morphology of the blend membranes was affected by two opposite factors:thermo-dynamic enhancement and kinetic hindrance.The membranes with denser sponge layers were formed at lower ratio of PU/PES,while more porous structure with enlarged macrovoids membranes were observed at higher PU content.The results indicated that adding PU to PES membrane,caused permeance improvement of the gases with nearly no change and/or reduction in ideal selectivity of CO2/CH4.Moreover,PES-ETPU membranes showed higher permeability and less CO2/CH4selectivity in comparison with PES-ESPU samples. For PES-ESPU membrane containing 1.5% ESPU,CO2permeance at 10 bar was improved up to 20% with almost no change in CO2/CH4selectivity with respect to PES.Finally,response surface methodology was used to evaluate the effects of the operating parameters on the permeance and ideal selectivity.     

An energy saving and fluorine-free electrorefining process for ultrahigh purity lead refining

The present paper reports a new fluoride-free and energy-saving lead electrolytic refining process in order to solve the serious problems of the existing Betts lead electrorefining process, such as low production efficiency,high energy consumption and fluorine pollution. In the process, a mixed solution of perchloric acid and lead perchlorate(HClO_4-Pb(ClO_4)_2) with the additives of gelatin and sodium lignin sulfonate is employed as the new electrolyte. The cathodic polarization curves show that HClO_4 is very stable, and there is no any reduction reaction of HClO_4 during the electrolytic process. The redox reactions of lead ions in HClO_4 solution are very reversible with an ultrahigh capacity efficiency, so the HClO_4 acts as a stable support electrolyte with higher ionic conductivity than the traditional H_2SiF_6 electrolyte. The results of the scale-up experiments show that under the optimal conditions of 2.8 mol·L~(-1) HClO_4, 0.4 mol·L~(-1) Pb(ClO_4)2 and electrolysis temperature of 45 ℃, the energy consumption is as low as 24.5 kW·h·(t Pb)~(-1) , only about 20% of that by Betts method at the same current density of 20 mA·cm~(-2), and the purity of the refined lead is up to 99.9992%, much higher than that specified by Chinese national standard(99.994%, GB/T 469-2013) and European standard(99.99%, EN 12659–1999).     

Modelling and simulation of two-bed PSA process for separating H_2 from methane steam reforming

Methane steam reforming is the main hydrogen production method in the industry. The product of methane steam reforming contains H_2, CH_4, CO and CO_2 and is then purified by pressure swing adsorption(PSA) technology. In this study, a layered two-bed PSA process was designed theoretically to purify H_2 from methane steam reforming off gas. The effects of adsorption pressure, adsorption time and purgeto-feed ratio(P/F ratio) on process performance were investigated to design a PSA process with more than99.95% purity and 80% recovery. Since the feed composition of the PSA process changes with the upstream process, the effect of the feed composition on the process performance was discussed as well.The result showed that the increase of CH_4 concentration, which was the weakest adsorbate, would have a negative impact on product purity.     

聚钛硅氧烷的溶胶-凝胶合成及转变规律研究

以甲基三甲氧基硅烷和钛酸四丁酯为原料、甲醇为溶剂、盐酸为催化剂采用溶胶-凝胶法制备了含有杂原子钛的甲基硅树脂基体，借助傅立叶变换红外光谱研究了其特性。为了全面地了解该体系的溶胶-凝胶转相规律，我们分别做出了加水量为理论水解量30％、40％、50％时体系的转相相图，并将其转换为直角坐标以考察加水量、甲醇用量对相转变的影响a结果表明，选用反应条件为：甲醇用量大于70％、水用量小于40％、反应温度为50℃、盐酸用量为10％时，容易形成含钛量大于50％的溶胶状态的甲基硅树脂。     

支链烷基苯磺酸钠的表征及表面性质的测定

为了研究支链烷基苯磺酸钠的构效关系,以苯为初始原料经酰化、格氏反应、氢化还原、磺化中和等4步合成了4种支链烷基苯磺酸钠。支链总碳原子数为16,苯环连接位置分别在支链的2,4,6和8位。它们的结构分别为:(A)CH3(CH2)13CH(CH3)C6H4SO3Na;(B)CH3(CH2)11CH(C3H7)C6H4SO3Na;(C)CH3(CH2)9CH(C5H11)C6H4SO3Na;(D)CH3(CH2)7CH(C7H15)C6H4SO3Na。经核磁和红外光谱确定了化合物的结构,用两相滴定方法确定了产物中烷基苯磺酸钠的质量分数均大于99%。用Wilhelmy-Plate法测定了4种支链烷基苯磺酸钠在30℃下的临界胶束浓度CMC(mmol/L)以及临界胶束浓度下的表面张力γCMC(mN/m)。CMC和γCMC值分别为:(A)0 112,35 96;(B)0 232,35 05;(C)0 420,33 86;(D)0 708,31 47。根据Gibbs吸附公式求出饱和吸附量Γm、饱和吸附面积Am以及表面压πCMC。发现随着苯环在烷基链上连接位置由2变化到8,CMC增大,γCMC降低。采用电导法测定了4种支链烷基苯磺酸钠的临界胶束浓度,其结果与表面张力法的测定结果一致。采用两种基于辛醇/水分配系数的方法预测了4种表面活性剂的CMC,结果表明,考虑了支链化的CMC与实验结果符合较好。     

煤热解过程中气态产物分布的研究

利用固定床热解装置对3种不同煤种进行了热解研究,考察了温度和煤的性质对热解气态产物以及硫元素逸出规律的影响,结果表明:除了煤的性质外,温度是影响热解产物分布的重要影响因素;同时CO和CO2的逸出量与煤中氧元素的含量有关,而生成CH4和气态烃的量与H/O原子比有很大关系;热解过程中含硫物质以H2S和少量COS的方式逸出到气相,而逸出的气态硫也与煤的含硫量有直接关系.     

钙钛矿型复合氧化物LaNiO_3的制备及其在CH_4/CO_2重整反应中的应用

采用溶胶-凝胶法制备钙钛矿型复合氧化物LaN iO3,采用XRD、TG-DTA作为表征手段,并且研究其在CH4/CO2重整反应中的应用。结果表明:经800℃焙烧,钙钛矿型复合氧化物的结构已经完全形成。在CH4/CO2重整反应中,H2/CO的比值总是小于1,这是因为存在逆水煤气反应。     

选择性催化还原NOx的反应机理研究

选择性催化还原法（SCR）脱除NOx具有较高的效率,是目前工业中应用最广泛的工艺。催化还原NOx的反应过程相当复杂。概括了H₂、CO、烃类、NH₃和尿素等作为还原剂选择性催化还原氮氧化物的各种反应机理,详细论述了催化还原过程中形成的中间体,如亚硝基甲烷、烯醇式物质[CH₂=O)、NO₂［NH₄+］₂、NO_y、C_xH_yO_zN、C_xH_yO_z、NO⁺、NCO或C_tH_xO_yN_z等,并讨论了催化剂和载体表面上的氧空缺和活性中心对SCR的影响，展望了这一领域的研究方向。     

DME/LPG混合体系的氧化反应与热稳定性

采用加速量热仪(ARC)分别测定了液化石油气(LPG)及其DME/LPG的氧化反应初始温度(To)和活化能(Ea),考察了添加剂对氧化反应的稳定性效应,用气相色谱-质谱联用仪(GC-MS)分析热分解产物。结果表明,LPG和DME/LPG的To分别为180℃和150℃,反应活化能Ea分别为203.2kJ·mol-1和188.6kJ·mol-1。氧的存在是导致LPG及其DME/LPG热稳定性下降重要因素,特别是有过氧化物存在下,由于自由基的引发,显著降低LPG、DME/LPG氧化反应的初始温度和反应活化能,在氧化反应体系中添加Fe、Al时,To和Ea值减小,稳定性降低,抗氧剂能提高它们的热稳定性。DME/LPG氧化产物主要有HCHO,CH3OH,HCOOCH3,HCOOH,CH3OCH2CH2OCH,H3CH(OH)CH3,CH3C(O)CH3,CH3CH2CH2OH,(CH3)2CHCH2OCH3,CH3CH2CH2CH2OCH3等20种化合物。     

等离子体煤热解与气化工艺的研究进展

介绍了煤在热等离子体中转化为小分子化合物的2个重要过程,即等离子体煤热解和气化的基本原理、应用及发展状况。在非氧化性气氛中,煤热解生成的气体产物主要是乙炔、氢气、一氧化碳,此外还有甲烷和乙烯等小分子烃,乙炔的收率与煤种、粉煤粒度、反应器结构、粉煤进料方式、进料速度及操作条件密切相关,等离子体中氢的存在有利于乙炔的产生;在氧化性气氛中,煤气化产物主要是一氧化碳和氢气,煤中碳的转化率达95%,合成气体积分数约85%,二氧化碳体积分数低于5%。指出等离子体应用于煤转化过程是煤洁净利用的有效方式,具有潜在的工业化应用前景。     

1，5－二（2－硝基苯氧基）－3－氮杂戊烷及其N－取代物的合成

报道了９个新型二硝基化合物的合成。将１，５－二（２－硝基苯氧基）－Ｎ－对甲苯磺酞基－３－氮杂戊烷用３３％ＨＢｒ－ＨＡｃ脱磺酰基得到１，５－二（２－硝基苯氧基）－３－氮杂戊烷。Ｎ－取代氮芥与邻硝基苯酚在碳酸钾存在下，在ＤＭＦ中，于８０℃缩合反应６ｈ得到Ｎ－取代－１，５－二（２－硝基苯氧基）－３－氮杂戊烷，取代基为：ＣＨ＿２ＣＨ＝ＣＨ＿２，Ｃ＿４Ｈ＿（９－ｎ），Ｃ＿５Ｈ＿（１１－ｎ），ＣＨ＿２ＣＨ＿２ＯＣＨ＿３，ＣＨ＿２ＣＨ＿２ＯＣ＿２Ｈ＿５，ＣＨ＿２ＣＨ＿２ＯＣ＿４Ｈ＿（９－ｎ），（ＣＨ＿２ＣＨ＿２Ｏ）＿２ＣＨ＿３，（ＣＨ＿２ＣＨ＿２Ｏ）＿２Ｃ＿４Ｈ＿（９－ｎ）。     

热扩散塔分离甲烷和氢的实验研究

引言用甲烷直接合成C_2以上的碳氢化合物非常困难,例如,由甲烷脱氢合成乙烯,按热力学计算在1000K下甲烷的平衡转化率只有4.8％,所以至今甲烷仍主要用作燃料．为了充分利用这一化工基础原料,作者利用热扩散塔进行了甲烷的催化脱氢反应,使反应与分离同时进行,大幅度提高了甲烷的转化率．为考察热扩散的分离效果,本文用甲烷脱氢反应的主要成分甲烷和氢混合物为原料,在热扩散塔中分别进行了空塔和填料塔的热扩散分离实验,考察了一些操作参数对分离效果的影响,以期对反应操作条件提供必要的参考．l原理所谓热扩散现象,就是在温度场…