循环流化床锅炉启动中存在的问题及分析

介绍了山西晋城煤业集团综合利用电厂1号炉在启动过程中遇到的问题,分析了发生这些问题的原因,探讨了预防这些问题的方法,提出了具体解决问题的措施。

新建循环流化床锅炉运行研究

介绍了陆续新建或投产大批的发电机组 ,主要以循环流化床锅炉为主 ,由于这些新建机组投产试运行过程中前期准备不足或设备自身缺陷 ,导致机组不能正常运行 ,针对这些问题进行分析研究 。

Numerical simulation on the fluidized bed gasification and CaO dechlorination of refuse derived fuel

A three-dimensional numerical model verified by previous experimental data is developed to simulate the fluidized bed gasification of refuse derived fuel （RDF）. The CaO dechlorination model obtained by the thermal gravity analysis （TGA） is coupled to investigate the process of CaO dechlorination. An Eulerian-Eulerian method is adopted to simulate the gas-solid flow and self-developed chemical reaction modules are used to simulate chemical reactions. Flow patterns, gasification results and dechlorination efficiency are obtained by numerical simulation. Meanwhile, simulations are performed to evaluate the effects of Ca/Cl molar ratio and temperature on dechlorination efficiency. The simulation results show that the presence of bubbles in the gasifier lowers the CaO dechlorination efficiency. Increasing the Ca/Cl molar ratio can enhance the dechlorination efficiency. However, with the temperature increasing, the dechlorination efficiency increases initially and then decreases. The optimal Ca/Cl molar ratio is in the range of 3. 0 to 3. 5 and the optimal temperature is 923K.

The Physical Models of Cyclone Diplegs in Fluidized Beds

In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed through the dipleg is partially overcome by the back pressure build-up in the dipleg and by adding a trickle valve at the bottom of the dipleg. Diplegs of primary cyclones, operating at a high solid loading behave differently from diplegs of secondary and tertiary cyclones which operate at low solid loading. Both types have been investigated by pressure drop measurements, visual observation and by measurements of the air flow rate flowing up the riser. The primary dipleg was also studied using electrical capacitance tomography. The results are reported hereafter and will give a first indication towards the right design of the dipleg and the selection of the trickle valve. The influence of gas flow in the dipleg on the conversion in a catalytic fluidized bed reactor is found to be negligible.

Preparation of TiCl4 with the Titanium Slag Containing Magnesia and Calcia in a Combined Fluidized Bed

This paper describes a new method for producing TiCl4 by chloridizing materials of high content CaO and MgO, in which a combined fluidized bed is used as a reactor to avoid agglomeration between particles caused by molten CaCl2 and MgCl2. The combined fluidized bed consists of at least a riser tube and a semi-circulating fluidized bed. Two kinds of high titanium slag, in which the total mass content of CaO and MgO is 2.03% and 9.09% respectively, are employed to examine the anti-agglomeration effect and the conversion of the materials when the temperature ranges are between 923.15K and 1073.15K, gas apparent velocity 0.7--1.1m.s-1, and inlet amount of solid materials is 4.6-7.0kg·h^-1. It is found that the anti-agglomeration effect in the combined fluidized bed is satisfactory and the new method can achieve a TiCl4 production capacity of 14.0-75.4t·m^-2·d^-1 in relation to 25.0-- 40.0t·m^-2·d^-1 from the conventional bubble bed. Furthermore, low-temperature chloridization, for example, at 923K or 973K, can also be used to produce TiCl4 and avoid agglomeration.

Fluidized-Bed Drying of Biological Materials:Two Case Studies

Drying is the last operation for processing most biomaterials. Due to the heat and moisture sensitivity of biomaterials, selections of drying methods and operating parameters are very important to keep the viability of these materials. In the present study, experiments were carried out in fluidized bed drying of photosynthetic microorganism liquid and mixed culture animal food. Results show that most activities can be kept in dried products. Appropriate operation parameters were determined.

Commercial Application of Novel FDFCC Grid Packing Type Stripper

The novel FDFCC grid packing stripper is used to raise the stripping efficiency of the equipment. This technology aims to increase the gas-solid contact area and improve the gas-solid contact efficiency. This technology has been applied in the revamped 1.05 Mt/a No. 1 FCC unit at the SINOPEC Changling Branch Company. The outcome on application of this equipment has revealed that the fluidization of the stripper was stable coupled with smooth operation. At a steam stripping load of less than 50% of the design value the spent catalyst had a lower H/C ratio, and the hydrogen content in the coke after revamp of the FCC unit decreased by 8.1% compared to the case before the equipment revamp. The spent catalyst had higher activity with the dry gas and coke yields reduced by over 0.5%, resulting in goodeconomic benefits.

Strength and thermal behavior of low weight foam geopolymer using circulating fluidized bed combustion fly ash

A comparative study of the influence of elevated temperature on foam geopolymer using circulating fluidized bed combustion fly ash（CFA） was reported. Foam geopoymers were prepared with different amounts of foam agent and different Si O2/Al2O3 molar ratios of 3.1, 3.4, and 3.8. The mechanical, thermo-physical properties and microstructure of the foam geopolymers before and after exposure to elevated temperature of 800, 1000, and 1200 ℃ were investigated. The specimen with Si O2/Al2O3 molar ratio of 3.8 exhibits the highest compressive strength, better microstructure and dimension stability before and after firing. Carnegeite, nepheline, and zeolite crystalline phases appearing after exposure may contribute to the good post-exposure strength. Low weight foam geopolymer using CFA can increase strength and maintain higher stability as high as 1000 ℃.

Conversion of Fuel-N to N2O and NOx during Coal Combustion in Combustors of Different Scale

With focus on investigating the effect of combustor scale on the conversion of fuel-N to NOx and N20, experiments are carried out in three combustors, including single coal particle combustion test rig, laboratory scale circulating fluidized-bed boiler （CFB） and full scale CFB in this work. For single coal particle combustion, the majority of f-uel-N （65%-82%） is released as NOx, while only a little （less than 8%） fuel-N yields N20. But in labora- tory scale CFB, the conversion of fuel-N to N20 is increases, but the conversion of fuel-N to NOx is quite less than that of single coal particle combustion. This is because much char in CFB can promote the NOx reduction by in- creasing N20 formation. In full scale CFB, both of the conversion of fuel-N to NOx and the conversion of fuel-N to N20 are smaller than laboratory scale CFB.

氨法烟气脱硫装置中硫酸铵后处理系统存在的问题及处理

河南晋开化工投资控股集团有限责任公司二分公司热电车间二期锅炉系统有2台循环流化床锅炉,配备1套氨法烟气脱硫装置,实际运行过程中,由于从离心机出来的硫酸铵水分难以控制,导致流化床风腔内积液、振动流化床床层积料和"坐床",以及旋转卸料阀的锥形料仓出口、旋转卸料阀进口堵塞而排料困难。分析与查找原因并采取有针对性的解决方案后,解决了硫酸铵后处理系统运行过程中的难点问题;同时,针对离心机出料水分控制的问题,提出在离心机出料口加装实时在线水分检测仪及实时监控系统的对策,以确保氨法烟气脱硫装置的优质高效运行。

Incipient Condition of Hang-up in a Long Standpipe-Hopper System for Geldart-D Powders

The incipient condition of hang-up for three Geldart-D powders has been experimentally studied in a 21 m long standpipe hopper system. Experimental results show that the pressure gradient for hang-up to occur is independent of the materials height in the hopper and the diameter of orifice and equals to (dpw/dl)s, which can be predicted by Eq. (7). While the corresponding gas velocity in the standpipe equals to the incipient fluidized velocity of particles at the high pressure and can be predicted by Kwauk's equation.

Novel PLA/Chitosan Composite MaterialsPrepared by SCF-CO_(2) Technique

Because of the incomparable merits （nontoxicity, non-remainder, fast transfer mass） of supercritical carbon dioxide fluid technique（SC-CO2）, it was used to developed a series of novel biodegradable tissue engineering scaffold materials in this research. The novel PLA/chitosan composite materials could be molded to different shapes, and the porosity of the materials were over 200 lam and connected. Chondrocyte cultivation, subcutaneous and intramuscular implantation were mainly discussed this paper. The results showed that the cells could well adhere, grow and multiplicate on the surface of the materials, which indicated good biocompatibility of the composite materials. The plantation test revealed that the PLA materials had already dismissed 2 month late in the body, while the composite materials could still keep certain strength and shape, and the most important things is the response of the tissue toward the implanted PLA/chitosan composite materials was mild and had far less inflammation than PLA materials. 8 to 16 weeks later, fiber membrane was stable; degradation of the materials was seen clear and tissue had already spread into it.

A Model for Agglomeration in Bio-fuel Fired Fluidized Bed

A mathematical model has been developed to describe the agglomeration process in bio-fuel fired fluidized bed combustor. Based on the balance mechanism of the adhesive force caused by liquid bonding between two parti- cles and the breaking force induced by bubbles in the fiuidized bed, the model considers modified Urbain model and chemical equilibrium calculations using FactSage modeling. This model prediction accounts for the evolve- ment of the adhesive and breaking forces, and clearly demonstrates that the different composition of ash, the in- creasing liquid phase matter and the fiuidization velocity cause defluidization in fluidized bed. In this model, it is the first time to hypothesize that the bonding stress between two particles is proportional to mass fraction of liq- uid phase and inversely proportional to the diameter of particles and viscosity of liquid phase. The defluidization time calculated by this model shows good agreement with that from the experimental data.