超临界机组发生FAC的因素及相互关系分析

为了减轻因流动加速腐蚀(FAC)引起的锅炉结垢加速、汽水系统管道厚度减小甚至爆裂现象，对超临界机组发生流动加速腐蚀的机理及其主要影响因素进行了研究，并讨论了管壁内表面粗糙度、蒸汽含汽率、pH值、溶氧量对FAC的影响，以及温度与pH值、温度与流速、pH值与溶解氧量、溶解氧量与氢电导率等影响因素之间的相互作用关系，最后结合实际电厂的运行数据验证了分析结果。研究表明：减小工质流速、管壁粗糙度和氢电导率，增大给水的pH值和溶解氧含量可以使FAC的腐蚀速率减小，超临界加氧处理时pH值应在8.9～9.2之间，溶解氧量范围为45～100μg/L,氢电导率的期望值在0.1μS/cm以下。由于各影响因素之间的作用十分复杂，本文只给出了大致范围和趋势，并未给出准确数据。     

Effects of structural parameters on water film properties of transpiring wall reactor

Corrosion and salt deposition problems severely restrict the industrialization of supercritical water oxidation. Transpiring wall reactor can effectively weaken these two problems by a protective water film. In this work, methanol was selected as organic matter, and the influences of vital structural parameters on water film properties and organic matter removal were studied via numerical simulation. The results indicate that higher than 99% of methanol conversion could be obtained and hardly affected by transpiration water layer, transpiring wall porosity and inner diameter. Increasing layer and porosity reduced reactor center temperature, but inner diameter's influence was lower relatively. Water film temperature reduced but coverage rate raised as layer, porosity, and inner diameter increased. Notably, the whole reactor was in supercritical state and coverage rate was only approximately 85% in the case of one layer. Increasing reactor length affected slightly the volume of the upper supercritical zone but enlarged the subcritical zone.     

Mathematical model for coal conversion in supercritical water: reacting multiphase flow with conjugate heat transfer

Providing heat for supercritical water gasification (SCWG) of coal by coupling subsequent products oxidation in integrated supercritical water reactor (ISWR) provides an effective method for directional control of temperature field and avoids excessive hot spots caused by uniform heating. An exploratory numerical model incorporating particle-fluid flow dynamics, multispecies transport and thermal coupling between endothermic coal gasification and exothermic product oxidation was established to simulate the reacting multiphase flow process of coal conversion in a novel lab-scale ISWR. An eleven-lump kinetic model was proposed for the prediction of chemical reactions. And the thermal coupling relationship was described by conjugate heat transfer boundary conditions (BC). Detailed physical and chemical field distribution in ISWR were analyzed and influence factors were discussed. The results showed that oxidation of gas products as inner heat source could promote the gasification reaction with only slight or even little maximum temperature increase of the pressure-bearing wall. Coal feeding rate and oxygen supply method significantly affected the field distribution. The multi-injection compressed-air supply method provided a more uniform temperature field but would reduce heat transfer temperature difference. The carbon gasification efficiency (CGE) in the gasification zone could easily reach up to 97% under mild conditions (less than 650 °C).     

两台竹浆碱回收锅炉NOx、SO2排放的探讨

根据两台竹浆碱回收锅炉的实际运行情况,对其结构与运行对污染物排放的影响进行了比较、分析。     

超临界二氧化碳干气密封相态分布规律与密封性能研究

以超临界二氧化碳干气密封为研究对象，分别以维里方程、Lucas方程描述二氧化碳真实气体效应、黏度的变化，在考虑阻塞流效应的同时，采用有限差分法对考虑离心惯性力效应的Reynolds方程与能量控制方程进行耦合求解，分析讨论了工况参数与槽形结构参数对其相态分布规律与密封性能的影响。研究表明：S-CO₂从密封端面进口至出口的流动过程中，如果工况参数设置合理，将由超临界态逐渐转变为气态，并不会出现液态；较低的进口压力、进口温度以及转速，均会容易导致潜在的凝结流动发生；相比于工况参数对相态分布的影响，槽形参数对相态分布的影响较小，近乎可以忽略；开启力除了随进口温度的升高而减小外，均随进口压力、转速、槽深、螺旋角的增大而增大；泄漏率随进口温度和转速的增大而减小，但其随进口压力、槽深、螺旋角的增大而增大。这些结果为进一步研究超临界二氧化碳干气密封提供了一定的支撑。     

梅花鹿鹿油的提取及成分检测

采用超临界CO2提取法从梅花鹿(Cervus nippon)鹿脂肪中提取鹿油,探讨提取工艺对鹿油提取率的影响。以鹿脂肪为原料,通过单因素试验和正交试验分别研究提取温度、提取压力、提取时间以及CO2流量对鹿油提取率的影响。研究结果表明,最佳的提取工艺为:提取温度45℃、提取压力40 MPa、提取时间150 min、CO2流量14 L/h。此时鹿油的提取率为44.81%。通过气相色谱-质谱法(gas chromatography mass spectrometry,GC-MS)联用对鹿油的成分进行检测,确定其含有16种脂肪酸,其中饱和脂肪酸和不饱和脂肪酸相对含量分别为69.840 9%和30.159 1%,主要脂肪酸有十六烷酸、十八烷酸及十八碳烯酸。     

SNCR脱硝技术在液态排渣煤粉工业锅炉中的应用

为了检验选择性非催化还原（SNCR）脱硝技术在高效低NO_x液态排渣煤粉工业锅炉中的应用效果，本文在一台8.4MW有机热载体锅炉炉膛内开展了SNCR脱硝技术工业化试验研究。选用尿素作为还原剂，搭建了工业化SNCR脱硝试验平台。在10%、15%、20%三种浓度尿素溶液下进行了不同尿素溶液喷射量、不同氧含量、不同锅炉负荷下的SNCR脱硝试验研究。试验结果表明，提出的“低NO_x燃烧+SNCR脱硝”耦合技术方案是可行的，SNCR脱硝效率在80%以上，完全能够达到烟气中NO_x低于50mg/m³的超低排放要求。