Fluidized bed combustion of coal

To conserve oil an alternative start-up procedure for the fluidized-bed combustor has been established which uses charcoal. The elutriated carbon loss has been measured for different grades of coal, and the variation of carbon loss with fluidization velocity is also reported. The results could be useful in the design of fluidized-bed combustion systems.     

协同增效抗痘系列化妆品配方开发

基于粉刺(青春痘、暗疮、痤疮)产生机理,从平衡油脂分泌、祛除皮肤多余油脂、溶解粉刺角栓、除菌、暗瘢修复、防UV-A紫外线、抗炎症、抗过敏、抗氧化、保湿、抗炎症后色素沉着、经皮给药(助渗)、活血和细致毛孔等方面介绍了协同增效抗痘化妆品的开发途径、活性成分和祛痘洗面奶、除菌消痤香皂、活血按摩膏、黑头导出液、消炎除痘焕采面膜、抗痘精华素、控油啫喱、消痘乳液、消痘膏、暗疮收口膏、祛印平疤修复霜、舒缓抗敏褪红霜、深层磨砂膏、收细毛孔精华等系列化妆品的配方和抗痘消痤护理流程。     

喷管型气体分布器和颗粒物性对提升管内气固两相流动行为的联合影响

在两套均采用喷管型气体分布器的循环流化床实验装置上分别采用河沙和FCC颗粒系统测试了提升管内的轴向压力梯度分布和局部颗粒浓度,研究了气体分布器结构和颗粒直径及密度对上行气固两相流动行为的共同影响.结果表明,当表观气速小于8.0 m·s-1时,粗重的河沙颗粒在喷管型气体分布器效应逐渐消失的过程中会出现不同程度的减速,而细轻的FCC颗粒在本实验的测试范围内则不存在上述现象.当采用喷管型气体分布器时,粗重的河沙颗粒在加速过程中,不仅其颗粒浓度显著高于FCC,而且其沿径向分布的不均匀程度也明显大于FCC;但在充分发展段,河沙的颗粒浓度不仅比FCC低,而且在径向的分布也更为均匀.     

Flow Characteristics in Slot‐Rectangular Spouted Beds with Draft Plates

An experimental investigation was conducted of slot‐rectangular spouted beds with air entry slots spanning the full thickness of the column and vertical draft plates intended to help control the solids circulation rate. With increasing superficial gas velocity, the flow between the draft plates changed from bubbling to slugging and then to spouting with dilute pneumatic between the plates and moving‐bed downward motion on both sides. However, there was difficulty maintaining stability and symmetrical flow on the two sides. Once spouting is established, pressure drops and local voidages vary with gas velocity, particle size and gas entry size in broadly similar manners as for conventional spouted beds     

Periodic Operation of Three — Phase Catalytic Reactors

Periodic operation of three phase reactors has been explored for more than two decades. This type of forcing changes selectivity and can increase either conversion or throughput. Experiments and simulation demonstrate periodic flow interruption or variation enhances reaction rates for concurrent trickle beds provided reactants are in the gas phase or can be volatilized under bed operating conditions. Temperature excursions in trickle beds can be controlled by either flow variation or switching the feed between an inert and a reactant. Several approaches to increasing rate through faster mass transfer using flow pulsing have been studied. Pulsing flow can be induced by low amplitude modulation. Periodic switching of flow direction in airlift reactors increases gas hold up and thereby the mass transfer rate. Periodic operation of three phase reactors, thus, appears to be a fertile area for engineering research.     

一轴三径氨合成塔的设计与应用

论述了氨合成塔进行一轴三径内件改造的设计原则和结构特点；介绍了催化剂的装填与升温还原过程；对改造后生产运行情况和经济效益进行了总结。     

Spouting Enhancement by Addition of Small Quantities of Liquid to Gas‐Spouted Beds

The addition of liquid water to beds of polystyrene particles exceeding 3 mm in diameter enhanced spouting by causing a decrease in the minimum spouting velocity. While the degree of enhancement is quantitatively comparable to what we reported previously for fluidized beds of large light hydrophobic particles, the mechanism is quite different. Enhancement of spouting takes place because the liquid congregates at the spout‐annulus interface, forming an effective nearly‐impermeable draft tube which then increases the velocity of the gas up the spout.     

Particle velocity profiles and solid flow patterns in spouted beds

A fibre optic probe system was used to measure the profiles of vertical particle velocities in the spout and the fountain of a half-column and a full-column spouted bed. In addition, a fibre optic image probe was employed to measure vertical particle velocity profiles in the annulus of the full-column. In the spout, radial profiles of vertical particle velocities were of near Gaussian distribution. Particle velocities along the spout axis in the half-column were 30% lower than in the full-column under identical operating conditions. In the half column, particle velocities adjacent to the front plate were approximately 24% lower than a few millimeters away. The fountain core expanded suddenly near the bed surface and then gradually contracted with height. The model of Grace and Mathur (1978) gave good predictions of fountain heights for the full-column. In the annulus region, there was a 28% difference between particle velocities adjacent to the column wall and those only 2 mm away. The integrated upward solids mass flow in the spout and the downward solids flow in the annulus matched well at different bed levels.     

Circulating fluidized bed hydrodynamics with air staging: an experimental study

The influence of secondary air injection (SA) on the hydrodynamics of circulating fluidized beds was studied in a 0.23-m ID riser. The secondary to primary air ratio, the vertical position, and the mode of injection (radial, tangential, and 45° entrance) are considered to be the key parameters of SA injection. It was found that the amount and location of SA have direct influence on the solids holdup and the segregation patterns in the riser. The SA divided the riser into two different flow zones: a dense turbulent zone below and a relatively dilute bed above the injection port. The mean solids velocity is found to be upwards with a greater magnitude in the center region. It is downwards with a smaller magnitude along the walls, suggesting core-annular flow structures for both above and below the SA injection region.     

SOLID-LIQUID MASS TRANSFER IN PACKED BEDS: ENHANCEMENT DUE TO ULTRASOUND

Enhancement in the solid-liquid mass transfer coefficient in packed beds due to sonic vibrations (ultrasound) has been studied. The results show considerable enhancement at relatively high power inputs. A correlation for the Sherwood number in such systems has been proposed.