Investigation on the physical properties of the charcoal briquettes prepared from wood sawdust and cotton stalk

The physical properties of the charcoal briquettes prepared from biomass waste are usually poor. In the paper, an alternative approach to the charcoal briquette preparation from the densified biomass briquette by carbonization was addressed. The carbonization process of the biomass briquettes prepared from cotton stalk (CS), wood sawdust (WS) and their blends was performed in a fixed bed at 400~600°C. The variation in the mass and volume of the biomass briquettes before and after the carbonization process and the physical properties of the resulted charcoal briquettes were investigated. The results indicate that the physical properties of the charcoal briquettes including bulk density and compression strength decreased firstly and then increased as the temperature increased. CS charcoal briquettes with better physical properties showed more volume shrinkage than WS charcoal briquettes after the carbonization process. However, the physical properties of the charcoal briquettes from the blends were poorer than expected due to the co-pyrolysis characteristics of CS and WS.     

生物质型煤的研制与应用

生物质型煤是一种新型型煤,是利用粉煤、生物质等通过一定的生产工艺制作而成,不仅有利于节约能源,同时也可以减少环境污染.文章重点介绍了水分、生物质添加量、粘结剂、原料煤粒度、成型压力、熟化过程、干燥程度对生物质型煤冷强度的影响,添加剂、生物质、配煤量以及煤的种类对生物质型煤热强度的影响.文章还分析了生物质型煤与生物质和煤在燃烧速度和着火性能上的区别,固硫效果与所加固硫剂量之间的关系,并提出了生物质型煤作为气化型煤今后应开展的研究方向与课题.     

锯末制备生物质成型燃料的试验研究

分别采用冷压成型和炭化成型工艺以锯末制备生物质成型燃料。冷压成型工艺主要考察原料水分、成型压力对燃料的成型性能影响。试验结果表明:原料水分为12%~16%,成型压力为60 MPa的条件下能够制得成型性能较好的生物质成型燃料,其密度与抗跌强度分别能够达到0.94 g/cm3和99%;炭化成型工艺主要考察混合料水分、无烟煤配比、J型粘结剂添加量、成型压力对燃料的成型性能影响。试验结果表明:无烟煤配比为50%、混合料水分为30%、J型粘结剂添加量为8%、成型压力为45 MPa的条件下能够制得成型性能较好的优质生物质成型燃料,其密度与抗跌强度分别为0.93 g/cm3和99.3%。     

型煤锅炉的选型及运行要点

介绍型煤锅炉在选型及运行方面应着重注意的几个问题:合理选用锅炉的受热面积、尽量选用采用新技术的炉型、正确认识型煤锅炉配用引风机的经济性、尽量燃用优质型煤、正确认识热水锅炉的出水温度等。     

玉米秸秆成型燃料锅炉的设计与试验研究

根据玉米秸秆成型燃料特性，通过详细的热工计算及一定加工工艺研制出适合于玉米秸秆成型燃料燃烧的专用锅炉，这种锅炉采用双层炉排结构，具有消烟除尘作用。不但燃烧效率高，气体及固体不完全燃烧损失小，而且排烟中的烟尘质量浓度，氮氧化物及二氧化硫体积分数低，符合国家锅炉的污染物排放标准要求。     

户用秸秆压块采暖装备优化设计与试验

北方农村地区以廉价秸秆压块燃料采暖是实现化石能源替代、减少污染物排放的重要措施。然而高效秸秆压块采暖炉的缺乏成为制约其发展的瓶颈。本文结合压块燃料燃烧特性,对前期研发的秸秆压块采暖装备进行优化设计与试验测试。结果表明：优化后自动送料装置可实现12h无人值守,炉膛内火焰脉动强烈;烟气中NO_x浓度、CO浓度、烟尘浓度分别为62.48mg/m^₃、522.04mg/m^₃、31.1mg/m^₃,降幅率分别为31.5%、46.8%、35.2%;林格曼烟气黑度小于1,额定热功率为10.19kW;热效率为84.69%,提高6.54%。     

Developing an Empirical Formula for the Assessment of the Char Yield of Pyrolyzed Lignocellulosic Materials

Abstract

A new empirical formula, based on the porosity, the botanical composition and the ash content of the precursor, is proposed for the assessment of the char yield, Y (wt%), of lignocellulosic materials pyrolyzed in a 600°C–900°C temperature range. The following equation is proposed:

Y (wt%) = (0.8815 ? 2.281/? + 61.44/?²)

· {[L(0.59 ? 2.74 × 10^?4 (t°C ? 600) + 0.22C]

+ A ? 0.1 E [1 + 2 × 10^?3 (600 ? t°C)]}

where ?, L, C, A, and E are parameters of the precursor, namely: porosity (%) and percentage (wt%) of lignin, cellulose, ash, and extractives, the t temperature, being in the Celsius grade.

The values calculated by the formula fit satisfactorily with the experimental results, the gap being less than 0.5%.     

火落现象及其在宝钢三期焦炉上的应用实践

介绍了焦炉生产过程中出现的火落现象及其判定方法，并根据宝钢三期焦炉的实际生产情况，进行了焦炉火落时间判定的试验研究，得到了特定工况下焦炉的火落判定经验关系式。经现场实际应用，结果表明：该火落时间判定公式有较高的准确度，其结果和人工判定的火落时间最大绝对误差仅为9min，完全可以替代人工进行火落时间的一，所做工作对同类焦炉有重要的借鉴意义。     

燃烧生物质成型燃料采暖热风炉的设计与试验

为弥补华北农村冬季传统采暖存在的不足,根据生物质成型燃料燃烧特性,设计制造出适合燃用生物质成型燃料的专用热风采暖炉,并对其进行了热工性能试验,结果表明,在较好工况下,其燃烧效率可达85.03％～92.06％,热效率可达44．82％～55．85％,为解决农村地区采暖问题提供了有效途径。     

Influence of moisture content on the direct gasification of dewatered sludge via supercritical water

In the present study, the feasibility of the direct gasification of dewatered sludge in supercritical water and the effect of water content on supercritical water gasification of the dewatered sludge were investigated using a high-pressure autoclave at a constant temperature of 400 °C with residence time of 60 min and by adjusting water content by adding distilled water or using air-dried dewatered sludge. The results showed that dewatered sludge can be directly gasified in supercritical water, with water content ranging from 75 to 95 wt%. The total gas production was increased by decreasing the water content, and the gas yield was decreased. The CO₂ yield was significantly affected by water content, whereas H₂, CH₄, and CO yields were slightly reduced. The liquid residue contained large amounts of organic matter (OM) and total phenols, thereby requiring further treatment before being discharged. The concentrations of OM and total phenols increased with a decrease in water content. Moreover, a serious carbonization reaction happened while carbon particles higher than 10 wt% (char/coke) were being formed in the solid residue.     

首钢预处理煤炼焦的产物特性研究

以首钢焦化厂常规炼焦配煤和预处理加工后炼焦用煤为实验原料,利用200kg焦炉和2kg焦炉进行对比炼焦实验研究。其中,首钢预处理炼焦煤增大了堆密度,减小了含水率。通过实验研究可得出如下结论:预处理煤炼焦的焦炭质量明显改善;采用首钢预处理煤炼焦,能提高生产能力,减少焦化废水;预处理煤炼焦的副产品中,焦油中芳香烃含量增加,煤气中氢气含量增加,甲烷含量减少;在工艺条件允许的情况下,尽量提高炼焦煤的堆密度和降低炼焦煤的含水率,有益于提高焦炭质量、提高炼焦产能和减少焦化废水。     

用于焦炉煤气重整合成气的管式透氧膜反应器的研制及其运行性能

采用热注浆法成功地制备了致密的混合导体BaCo0.7Fe0．2Nb0.1O3-δ（BCFNO）透氧膜管,应用在焦炉煤气中甲烷部分氧化制合成气反应中,可以利用透氧膜以空气为氧源和焦炉煤气中的甲烷反应制合成气,实现膜分离制氧和甲烷部分氧化反应的一体化。试验结果表明,当反应温度在875℃时,膜的透氧量为8．7mL／（cm^2·min）,焦炉煤气中甲烷的转化率可以达到94％以上,H2的选择性在90％左右。试验结果还表明,透氧膜管的性能可靠稳定,经过长时间的运行膜管没有出现破裂,在富氢焦炉煤气气氛下表现出很好的稳定性。     

干熄焦红焦烘炉的研究与应用

本文着重阐述了干熄焦红焦烘炉的理论依据、原理、方案等,并对红焦烘炉和煤气烘炉的实施效果进行了评价比较,指出了对年修后的干熄炉红焦烘炉的优点,这对焦化干熄焦系统具有很好的推广价值。     

烟煤焦催化还原NO_x实验研究

研究了烟煤焦在催化剂的作用下对 NOx 的还原过程。实验发现 ,烟煤焦中廉价催化剂的存在对煤焦异相还原 NOx 有很大的影响 ,在合适的反应温度和化学当量比 ( SR)条件下 ,煤焦中的催化剂能降低 NOx 还原反应的活化能 ,加快 NOx 还原反应的速度 ,提高 NOx 的还原率。实验使用两种催化剂后 ,NOx 的还原率可超过 5 0 % ,几乎达到与褐煤及气体再燃燃料相同的再燃效果     

Optimization of process parameters for preparation of powdered activated coke to achieve maximum SO2 adsorption using response surface methodology

Powdered activated coke (PAC) is a good adsorbent of SO₂, but its adsorption capacity is affected by many factors in the preparation process. To prepare the PAC with a high SO₂ adsorption capacity using JJ-coal under flue gas atmosphere, six parameters (oxygen-coal equivalent ratio, reaction temperature, reaction time, O₂ concentration, CO₂ concentration, and H₂O concentration) were screened and optimized using the response surface methodology (RSM). The results of factor screening experiment show that reaction temperature, O₂ concentration, and H₂O (g) concentration are the significant factors. Then, a quadratic polynomial regression model between the significant factors and SO₂ adsorption capacity was established using the central composite design (CCD). The model optimization results indicate that when reaction temperature is 904.74°C, O₂ concentration is 4.67%, H₂O concentration is 27.98%, the PAC (PAC-OP) prepared had a higher SO₂ adsorption capacity of 68.15 mg/g while its SO₂ adsorption capacity from a validation experiment is 68.82 mg/g, and the error with the optimal value is 0.98%. Compared to two typical commercial activated cokes (ACs), PAC-OP has relatively more developed pore structures, and its S_BET and V_tot are 349 m²/g and 0.1475 cm³/g, significantly higher than the 186 m²/g and 0.1041 cm³/g of AC1, and the 132 m²/g and 0.0768 cm³/g of AC2. Besides, it also has abundant oxygen-containing functional groups, its surface O content being 12.09%, higher than the 10.42% of AC1 and 10.49% of AC2. Inevitably, the SO₂ adsorption capacity of PAC-OP is also significantly higher than that of both AC1 and AC2, which is 68.82 mg/g versus 32.53 mg/g and 24.79 mg/g, respectively.     

Preparation and characterization of bio-oil by microwave pyrolysis of biomass

A low temperature method was used to produce bio-oil from fir sawdust by means of microwave pyrolysis. Effects of reaction temperature, ratios of the microwave absorption medium to sawdust, and reaction time on the yield of bio-oil were investigated. The results show that an optimized yield of 21.22% is achieved. Bio-oil obtained was analyzed by gas chromatography-mass spectrometry and Fourier transform infrared, and the result reveals that the product mainly consists of phenolic compounds with esteric compounds as the minor components. Thermal weight loss curves of bio-oil were determined by thermogravimetry-differential thermal analysis in the oxygen atmosphere at different super-heating rates, and combustion kinetic parameters were calculated.     

双循环流化床锅炉副床投入运行中防止原料层结焦的方法

本文主要对生产过程中副床原始料层结焦的原因进行分析,并提出解决办法。     

Preparation of NiO / PC catalyst with plasma for cracking tar to produce flammable gas

To increase the use of lignite, the tar was pyrolyzed with pyrolysis coke (PC) to produce more combustible gases such as H₂, CH₄, and CO. NiO/PC catalyst with plasma was prepared, and the influence of PC and NiO/PC catalyst on flammable gas was investigated in a two-stage fixed reactor. The catalysts were characterized by SEM, BET, XPS and XRD to analyze the tar cracking mechanism. The results were: (1) PC was prepared at different heating rates, and when the heating rate reached 20 °C/min, the amount of flammable gas was 5.4 L. (2) NiO/PC catalyst was modified with plasma in three background gases withO₂ being the best, mainly because of the increase of the oxygen functional groups. (3) PC was modified and calcined with plasma, and when the power reached 40 W, it produced the most combustible gas, and the volume could grow by 94.4%.     

燃用焦炉煤气的燃气轮机性能分析

将焦炉煤气用于燃气轮机发电,是有效利用焦炉煤气的形式。选用M701F型燃气轮机,对其燃用焦炉煤气的性能进行研究。为了得到更多关于该燃气轮机的性能参数,首先对该燃气轮机燃用天然气的设计工况下的性能参数进行计算,将计算结果输入ASPEN PLUS软件进行模拟,得到与设计值极为吻合结果。根据这些数据,计算M701F型燃气轮机燃用焦炉煤气工况下的燃气轮机性能参数,同样将计算结果输入软件进行模拟,最后得出结果。     

Utilization of pyrolytic char derived from bamboo chips for furfural removal: Kinetics,isotherm, and thermodynamics

Bamboo charcoal obtained from the pyrolysis of bamboo chips was used to remove furfural, a representative fermentation inhibitor in hydrolyzates or pyrolysis oil. Kinetics, isotherm, and thermodynamic calculations were performed. The adsorption process can be well depicted by Ho’s pseudo-second-order model. The particle diffusion of homogeneous particle diffusion model (HPDM) and shrinking core model (SCM) was found to be the controlling step. Isotherm analysis indicated the adsorption feature took place by a nonideal adsorption. Thermodynamic calculation suggested that ΔH° > 0, ΔG° < 0, ΔS° > 0, and E_a value was 2.02 kJ/mol. The comparison results demonstrate bamboo charcoal is a promising adsorbent for furfural removal.