高浓度化工放心液流化床焚烧炉的研制与应用

介绍了高浓度废液流化床焚烧炉的工作原理和结构，对流化床焚炉的设计以及为提高废液焚烧效率和辅助燃料利用率、防止二次污染所采用的关键技术进行了探讨和分析。该流化床焚烧炉具有綮杰烧彻底、环保性能优良、运行费用低廉等显著优点。     

流化床焚烧处理有机浓缩废液的结焦结渣特性

温度是有机废液焚烧的重要参数,也是影响焚烧炉结焦结渣的重要因素.实验研究分析了采用流化床焚烧处理有机浓缩废液时,焚烧温度对结焦结渣的影响.研究表明：随着焚烧温度的升高,焚烧炉的结焦结渣程度逐渐加大,渣样晶相由以Na₂SO₄、NaCl等为主转变为以Na₂SO₄、Na₂Si₃O₇等为主,且Na₂Si₃O₇在渣样中的比重随着焚烧温度的升高而升高;向焚烧炉添加石灰石、Fe₂O₃粉末、高岭黏土等添加剂能够较好地抑制焚烧炉的结焦结渣.     

氯硅废弃物焚烧特性实验研究

根据工业氯硅废弃物处理现状,设计开发了流化床焚烧试验台,对氯硅废弃物焚烧炉内温升特性和一次风/二次风配比对炉内燃烧温度的影响进行研究。结果表明,废液主要在流化床焚烧炉密相区燃烧,其温度维持在850℃左右;一次风/二次风配比为60:40时,其飞灰的灼烧率最低,燃烧效率最高,工况运行最优。     

北京新型有机废液焚烧炉填补国内空白

北京市机电研究院环保所研制的ＬＺＺ—２０—ＹＷ型有机废液焚烧炉于近日被评为国家级重点新产品。该设备填补了国产化有机废液焚烧炉的空白，设备性能价格比高，个别指标达到美国标准，具有良好的社会效益和经济效益。ＬＺＺ—２０—ＹＷ型有机废液焚烧炉设计合理，自动化水平高，运行安全可靠，焚烧效率高，对二氯苯等多种有害废液焚烧率达９９．９９％，所测项目均达国家排放标准。现场考察证明该系统结构紧凑，使用有效，对有机废液处理效果良好，处于国内领先水平。该项目开拓了国产化设备对强酸强碱及高浓度有机废液进行直接焚烧的新…     

用于处理BDO/PTMEG装置废液的焚烧炉设计

BDO(1,4-丁二醇)和PTMEG(聚四氢呋喃)装置生产过程中会产生大量高浓度废液,并含有盐分,极难处理。文章从焚烧法基本原则出发,根据废液组分特性,设计一套焚烧炉,配套处理BDO和PTMEG生产装置产生的废液,设计处理废液总量6 000 kg/h。焚烧炉设计主要包括:焚烧炉运行温度选择、燃烧器组织燃烧、烟气停留时间选取、燃烧炉膛衬里选择以及考虑烟气中熔盐腐蚀等几部分工作。本套焚烧炉经过1年多的实际运行,整套装置运行安全、可靠,性能满足30%—110%运行能力,燃烧效率不低于99.9%,焚烧残渣的热灼减率小于5%,烟气排放指标满足国家环保标准GB18484—2001《危险废弃物焚烧污染控制标准》。     

流化床焚烧技术的设计及污染物排放与防治

围绕流化床废物焚烧处理技术,对鼓泡式流化床、内旋流式流化床和循环流化床3种主要流化床焚烧炉的特点进行了介绍,并对废物和填料颗粒的性质、载气的性质和气速、温度和热平衡等参数对流化床焚烧技术设计过程的影响进行了探讨。最后,对流化床焚烧过程中主要污染物CO、HCl、SO_x、NO_x及二噁英类物质的产生机理进行了分析,总结了这些污染物的防治方法。     

有机氟化工废物焚烧炉燃烧工艺及自动控制

介绍了有机氟化工废物焚烧炉工艺及自动控制系统,从焚烧理论出发,推导出了废液、废气及燃气与空气的燃烧比例计算方法,由此计算得到,1 kg废液和1 m3废气完全焚烧分别需要空气1.574 m3和2.370 m3。在实际使用过程中得到验证,并取得较好效果。     

污泥焚烧设备的比较与选择

污泥是污水处理的副产物,含有大量的有害物质。污泥焚烧是将污泥中的有机物在高温条件下氧化分解为二氧化碳和水,同时回收热能,能实现污泥的无害化治理与资源化利用,是当前最主要的污泥热处理利用方法。本文对多膛式焚烧炉、流化床焚烧炉、回转窑式焚烧炉、炉排式焚烧炉等多种污泥焚烧设备的结构、运行方式及主要优缺点进行介绍,以期为污泥焚烧设备的合理选型并拓展污泥焚烧处理技术的应用范围提供指导。     

油田污泥焚烧处理技术分析

油田污泥的处理是目前国内外各大油田面临的一个棘手问题。本文分析了各种常见焚烧炉装置在焚烧油田污泥时的特点,认为流化床焚烧炉比较适合油田污泥的焚烧。同时,对焚烧处理过程中的污泥预处理系统也进行了分析。根据对油田污泥焚烧后形成的排烟和排渣特点的分析,认为只要采取恰当的措施,焚烧处理方法能比较容易地满足相关排放标准。     

污泥干化焚烧处置在城市污水处理厂的应用

本文主要介绍泉州市中心市区污水处理厂污泥处理、处置现状,以及如何优化选择处置方式,选用适宜污水处理厂污泥焚烧处置的蒸汽间接干化法和循环流化床焚烧工艺,对泉州市中心市区污水处理厂产生的污泥先干化至含水率40%～45%,再进入焚烧炉与生活垃圾进行掺烧处置.     

A diffusion model for particle mixing in a packed bed of burning solids

Particle mixing caused by grate movement in a packed bed of solids is an important process for biomass combustion and waste incineration. In this paper, a diffusion model for particle mixing in a burning bed is proposed and the related diffusion coefficient is measured. The diffusion model was incorporated into a combustion model for waste incineration in an actual full-scale bed and numerical calculations were carried to assess the effect of different mixing levels on the burning characteristics of the furnace. In-bed measurement of temperature, oxygen concentration and particle movement was also made using a special electronic device. It is found that the modelled flame front reaches the bed bottom at an earlier stage for a higher level of particle mixing; the average burning rate ranges from 0.05 to 0.13 kg/m² s and the mass loss rate for a higher mixing level can be twice of that for a lower mixing level. However, excessive mixing can cause significant delay in ignition or even extinction of the bed combustion; the obtained local air to fuel stoichiometric ratio covers a range from sub-stoichiometric (0.6 for the highest mixing level) to super-stoichiometric (1.6 for the lowest mixing level); the carbon in ash ranges from 3.5 to 10.5%; the most reasonable range of the particle-mixing (diffusion) coefficient is from 1.8 to 6.0 cm²/min for a full-scale bed, according to the calculation.     

Model of combustion and dispersion of carbon deposited on porous bed material during bubbling fluidized bed combustion

Porous bed materials capture volatile matter as carbon deposits during fluidized bed combustion of high-volatile fuels such as biomass and wastes. Carbon deposits burn in a dense bed mixed with bed materials; thereby enhancing horizontal dispersion of carbonaceous materials. Commercial scaling-up requires a model that simultaneously assesses carbon deposit combustion and horizontal solid dispersion. This study measured the carbon deposit combustion rate using a fluidized bed. A one-dimensional model of carbon deposit combustion in a fluidized bed is based on the carbon deposit burning rate. A two-dimensional model incorporates reactions and solid dispersion to predict the horizontal concentration profile. Experiments using a bubbling fluidized bed validated that model.     

Effect of fuel properties on biomass combustion. Part II. Modelling approach—identification of the controlling factors

Biomass fuels come from many varieties of sources resulting in a wide range of physical and chemical properties. In this work, mathematical models of a packed bed system were employed to simulate the effects of four fuel properties on the burning characteristics in terms of burning rate, combustion stoichiometry, flue gas composition and solid-phase temperature. Numerical calculations were carried out and results were compared with measurements wherever possible. It was found that burning rate is mostly influenced by fuel size and smaller fuels result in higher combustion rate due to increased reacting surface area and enhanced gas-phase mixing in the bed; combustion stoichiometry is equally influenced by fuel LCV and size as a consequence of variation in burning rate as well as the mass ratio of combustible elements to the oxygen in the fuel; for the solid-phase temperature, material density has the strongest influence and a denser material has a higher maximum bed temperature as it results in a less fuel-rich combustion condition; while CO concentration in the flue gases is mostly affected by both fuel calorific value and size, CH₄ in the exiting flow is greatly affected by material density due to change in reaction zone thickness.     

Enhancement of combustion efficiency with mixing ratio during fluidized bed combustion of anthracite and bituminous blended coal

In order to investigate the effect of mixing ratio of bituminous coal to blended coal on the enhancement of combustion efficiency, combustion experiments of blended coal with anthracite and bituminous are done in a laboratory scale fluidized bed combustor (10.8 cm ID and 170 cm height). The gross heating values of anthracite and bituminous coal used in this study are 2,810 cal/g and 6,572 cal/g, respectively. Experimental parameters are fuel feed rate, superficial gas velocity and mixing ratio of bituminous coal to blended coal. The combustion efficiency increases with the mixing ratio of bituminous coal due to the lower unburned carbon losses and higher burning velocity of bituminous coal. The rate of combustion in the combustor was increased with mixing ratio resulted from a higher burning velocity of bituminous coal. The measured combustion efficiency experimentally is about 3.5-12.4% higher than that of the calculated value based on the individual combustion of anthracite and bituminous coal under the same operating conditions. The optimum mixing ratio (MR) of bituminous coal determined is around 0.75 in this study. This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University.     

Effects of fuel devolatilisation on the combustion of wood chips and incineration of simulated municipal solid wastes in a packed bed

Detailed mathematical simulations as well as experiments have been carried out for the combustion of wood chips and the incineration of simulated municipal solid wastes in a bench-top stationary bed and the effects of devolatilisation rate and moisture level in the fuel were assessed in terms of ignition time, burning rate, reaction zone thickness, peak flame temperature, combustion stoichiometry and unburned gas emissions at the bed top. It is found that devolatilisation kinetic rate has a noticeable effects on the ignition time, peak flame temperature, CO and H₂ emissions at the bed top and the proportion of char burned in the final stage (char burning only) of the combustion. However, it has only a minor effect on the other parameters. Reaction zone thickness ranges from 20 to 55 mm depending on the moisture level in fuel and an increase in the moisture level causes a shift of the combustion stoichiometry to more fuel-lean conditions.     

Correlation of parameters in the burning rate law and its influence on intraballistic characteristics of a rocket motor

Experimental data demonstrating the correlation of parameters in the power-law dependence of the burning rate of composite solid propellants on pressure are reported. The reasons for changes in the burning rate due to changes in propellant mixing conditions are discussed. The deviation of the pressure in the combustor of a solid-propellant rocket motor is analyzed with due allowance for the correlation of parameters in the burning rate law. It is shown that the relative deviation of the burning rate depends on pressure at which propellant combustion occurs. Moreover, for each propellant, there exists a pressure level at which the burning rate deviation is theoretically equal to zero, regardless of the differences in propellant compositions and properties.     

Prediction of the distribution of alkali and trace elements between the condensed and gaseous phases in a municipal solid waste incinerator

The FactSage thermodynamic calculation package and databases have been used to predict the equilibrium composition of the solid, liquid and gaseous products from municipal solid waste incineration. One series of calculations has considered the equilibrium for municipal waste combustion over a range of temperatures (850-1350 °C) that includes the typical combustion temperature of 950 °C and covers excursions to both lower and higher temperatures. A second set covers cooling of the combustion gas to 300 °C and the formation of condensates. However, it is recognised that the lower the temperature the greater the importance of kinetics and no attempt is made to deal with such topics as nucleation by pre-existing airborne particulates. Consideration is given to the effect of oxygen potential together with alkali, chlorine, and water content on the equilibrium products. Further calculations conceptualising “local equilibrium” around specific metal-containing items in the waste stream, for example a CRT tube, have illustrated how lack of global equilibrium, arising from non-uniformity in the burning bed could lead to atypical local metal distributions. Combined, these calculations provide a greater understanding of the behaviour of metals in municipal waste incineration than previous studies, accounting to some extent for the great variation in waste composition and local combustion conditions in a complex and variable industrial system.     

Influence of Particle Size and Mixing Technology on Combustion of HMX/Al Compositions

In this work, two widely used components of high‐energy condensed systems – HMX and aluminium – were studied. Morphology, thermal behaviour, chemical purity and combustion parameters of HMX as a monopropellant and Al/HMX as a binary system were investigated using particles of different sizes. It was shown that in spite of the differences in composition and particle size, combustion velocities are almost identical for micrometer‐sized HMX (m‐HMX) and ultrafine HMX (u‐HMX) monopropellants under pressure from 2 to 10 MPa. Replacement of the micrometer‐sized aluminium with ultrafine one in the system with m‐HMX leads to a burning rate increase by a factor of 2.5 and the combustion completeness raise by a factor of 4. Two mixing techniques to prepare binary Al/HMX compositions were applied: conventional and ‘wet’ technique with ultrasonic processing in liquid. Applying wet mixing results in a burning rate increase of 18% compared to the conventional mixing for systems with ultrafine metal. The influence of the component's particle size and the composition microstructure on the burning rate of energetic systems is discussed and analysed.     

Effect of mechanochemical activation and microgrinding on the intensity of combustion of solid fuel

The effect of mechanochemical activation and microgrinding on the intensity of combustion of solid fuel particles was studied. As applied to the rapid process of the combustion of solid fuel particles, mechanochemical activation was simulated within the framework of nonequilibrium thermodynamics with the expansion of the classical dependence of the local entropy of state of the reacting system on relaxation phenomena. The dependences of the intensity of burning (mass loss time) of deformed organic solid fuel particles on the relaxation processes of the momentum transfer of their excited states and on the mutual orientation of shear stresses and the first difference in normal stresses (a steric factor), which compensate for temperature power consumption, were established. The rate of combustion is determined by the size of burning particles, their density, and a ratio between the elastic and dissipative scattering of mechanical energy in the particles, which increases the diffusion mobility of burning components with a decrease in the time of their burning. The ranges of variation in the parameters of the burning system in which the particle size or mechanoactivation exerts a considerable effect on the combustion time of fuel particles were recognized. Experiments on the torch combustion of coal-dust fuel as the cumulative combustion of its particles confirmed the effect of mechanoactivation.     

垃圾焚烧炉热力模型研究

将焚烧炉划分为加热干燥区、热解区、残炭燃烧区、挥发分燃烧区、辐射传热区 ,使建立的热力模型比 Essenhigh模型更接近实际过程。对各区域物理化学过程进行了较系统的分析 ,得到了稳定完全燃烧时 ,固体垃圾和可燃气在各区域所需的时间。结果表明 :加热和热解对整个焚烧过程起控制作用 ;保证挥发分的完全燃烧 ,是组织好燃烧工况的关键。