核桃壳热解分级冷凝产物分布特性研究

为研究热解温度、载气流量和冷凝温度对核桃壳热解产物分布的影响,在实验室研制的生物质热解与分级冷凝装置上对核桃壳热解进行实验研究,结果表明:液体产物收率随着热解温度的升高而增加,但增加速率逐步降低;载气流量对液体产物总收率及各级液体产物收率影响较小;冷凝温度对液体产物总收率影响较小,但对各级生物油的收率影响较大。GC/MS分析表明:热解温度为450～500℃时,酚类物质含量达到最大值;随着二级冷凝器温度的升高,二级生物油中酚类物质富集程度逐渐提高,酸类物质的富集程度逐渐降低,二级生物油的收率逐渐下降。     

化工装置蒸汽冷凝液处理方法探讨

化工装置生产过程中 ,蒸汽作为反应原料、加热和动力介质 ,产生大量蒸汽冷凝液。其特点是分布面广 ,因设备、管道泄漏或腐蚀 ,难免含有各种杂质。本文介绍了三套不同类型化工装置在冷凝液回收利用方面的方法。1　某年产 30 0 kt天然气合成氨装置该装置根据冷凝液的不同品质 ,采用分散回收处理流程。回收冷凝液 87t/h。1 .1　工艺蒸汽冷凝液　工艺冷凝液来自加入工艺系统气体中进行化学反应的过剩蒸汽 ,经冷凝后从工艺气体中分离出来的 ,含有多种杂质的冷凝液 ,数量 31 t/h。要回收这部分冷凝液必须先进行预处理 ,以除去溶解在冷凝液中的杂质…     

生物质快速热解装置尾气的循环利用

基于流化床生物质快速热解制备生物油技术,从产物中的不可冷凝气体着手,主要目的是使能源得到最大化利用,同时,又不会对环境造成危害.在分析了传统快速热解工艺的基础上,提出了一种新的利用尾气(不可冷凝气体)的方法.     

法国VICHEM公司利用"汽化"技术处理化工废弃物

法国VICHEM公司是一家专门从事废弃物处理,以交钥匙的方式进行系统设计、设备安装和调试的专业工程公司,已经有50年的从业历史。该公司设计的名为“汽化处理”的高温氧化系统,可以对气体和高浓度的液体废弃物进行处理,产生的二恶英和氧化氮量极低。由于技术上的先进性,该系统在     

矿井柴油机的液体中和器

按照现行规章,采用功率大于18.4kW柴油机的矿井自行车辆,都应装备两级废气中和系统.第一级采用催化中和器,第二级采用液体中和器.废气从柴油机中排入催化中和器,未完全燃烧的燃油产物在催化中和器中再度氧化后,导入液体中和器.废气成分中含有丙烯醛、甲醛、亚硫酸酐等可溶于水的成分,及焦炭、炭黑和金属等固体颗粒.用液体中和废气的实质是为气体和液体的接触创造一定条件.这样,废气中的部分有害成分就溶于液体中,而固体颗粒就下沉.目前,用水作吸收液体.为了提高液体中和器     

生物质热裂解技术的实验研究

以木屑为原料,利用从荷兰引进的旋转锥反应器闪速热裂解装置进行了热裂解试验。对热裂解产物的组成及反应的物质平衡进行了分析。结果表明：木屑热裂解产物由生物油、不可冷凝气体和木炭组成。其中,生物油成分复杂,低热值为１６ ５９５ｋＪ／ｋｇ;不可冷凝气体主要由ＣＯ,ＣＨ４ ,ＣＯ２ ,Ｈ２ 和Ｈ２Ｏ蒸汽组成。在反应器温度为６００℃,旋风机温度为５００ ℃,旋转锥频率为１０Ｈｚ 条件下,当木屑喂入率为２６．４２ｋｇ／ｈ 时,生物油、不可冷凝气体及木炭的得率分别为５３．３７％ ,２１ ．４５％ 和２５．１６％ 。     

新型加压填料饱和器及其关键结构研究

为了进一步揭示HAT循环的集成和运行的规律,促进HAT循环的商业化,搭建了100kW级的HAT循环示范系统。本文主要工作是研制HAT循环的关键部件加压饱和器及其内部气体分布器、液体分布器、气液两相测量装置等。在前人工作基础上,设计了分布性能好、压力损失小的双向环流式气体分布器。利用FLU-ENT软件对其进行了数值分析,结果显示该气体分布器可以满足饱和器内气流分布均匀性的要求。     

旋转气体介质对环膜液体射流破碎不稳定性影响的研究

利用线性不稳定性理论研究了旋转气体介质对黏性环膜液体射流破碎的影响。研究结果表明,无论是轴对称模式还是非轴对称模式,由液体环膜内部气体介质旋转所产生的离心力是液体射流的失稳因素,有助于液体射流的破碎。另外,由液体环膜外部气体介质旋转所产生的离心力是液体射流的促稳因素,不利于液体射流的破碎。当相同强度的旋转同时存在于内部和外部气体介质中时,对于轴对称模式,内部气体介质的影响显著,而对于非轴对称模式,则外部气体介质的影响更为明显。通常情况下,非轴对称模式的扰动增长率强于轴对称模式的扰动增长率,因此会在环膜液体射流的破碎中占据主导地位。     

滴入式气体渗碳炉的原理

对钢件表面进行渗碳以提高它的机械性能是众所周知的。渗碳有三种类型。固体渗碳在均匀性、重复性和操作性等方面都不理想,因为不需要特殊设备,在要求性能不高的情况下,还被工厂所利用。液体渗碳加热快易变形,处理后需清洗,处理时有烟气,工作环境差。气体渗碳较液体渗碳有优点,因而发展很快。     

黄豆秆两级连续热解特性研究

为优化生物质热解过程,获得更高品质的生物油,利用热裂解仪-气相色谱/质谱联用仪(Py-GC/MS)对黄豆秆进行两级连续热解研究,并利用热重分析仪(TG)研究黄豆秆在不同升温速率下的失重特性。结果表明:黄豆秆热失重过程主要分为4个阶段,其中200～450℃为主要的热解区间,此阶段内基本完成半纤维素和纤维素的热解。与单级热解相比,两级连续热解能减少组分间的相互作用和产物的二次反应,进而提高总可冷凝挥发性有机产物的产率。250℃和300℃时能提高各类产物的产率,尤其可显著提高酚类和芳香烃类等源于木质素的产物产率;而400℃和450℃时主要提高酸类、呋喃类和环戊烯酮类等源于半纤维素和纤维素的产物的含量和产率,有利于提高生物油的品质和分离利用。     

Hydrogen production from nuclear fission product waste heat and use in gas turbines

An analysis has been made on the feasibility of producing hydrogen using fission product waste heat and its subsequent combustion in gas turbines. The work has been performed in three distinct phases.In the first phase, a system using heat generated from radioactive wastes has been designed which produces saturated steam. This steam is sent through a turbogenerator to produce electricity. The electrical power output of this system has been calculated as a function of fission product decay time, solidified form of fission products, as well as numerous other parameters.In the second phase, the electrical energy produced is used to electrolyze water, which in turn produces hydrogen. The amount of hydrogen produced (lb/h) has been calculated for varying electrical inputs, electrolyzer efficiencies, and feedwater temperatures. This hydrogen is then assumed to be liquified and stored. Finally, the third phase considers the burning of this hydrogen in a standard marine gas turbine.     

钢铁企业日际煤气最优混合配比的算法研究

钢铁企业根据日际生产计划,可以确定日际生产的副产煤气总体积、各煤气消耗设备的热量需求。为进一步确定各设备消耗的混合煤气中的煤气配比,使煤气产耗平衡,提出混合煤气逆向分解方法,将各设备消耗的混合煤气中所包含的单一煤气成分体积,表示为各设备获得热量与混合煤气热值的函数,在此基础上建立日际煤气最优混合配比算法模型。该模型以各设备的混合煤气热值及热量作为决策变量,以各煤气消耗设备的热量偏差最小为目标,综合考虑各煤气设备的热值要求、自备电厂的热值、热量要求及煤气体积守恒等约束条件。采用遗传算法求解,并利用遗传算法基因初始化的范围区间控制混合煤气的热值范围。算例结果表明:建立的日际煤气最优混合配比算法模型,在优化煤气分配的同时,显著减少了约束方程及决策变量的数量,为钢铁企业日际煤气平衡调度提供了理论支撑。     

Numerical modeling of the gasification based biomass co-firing in a 600 MW pulverized coal boiler

Gasification based biomass co-firing was an attractive technology for biomass utilization. Compared to directly co-firing of biomass and coal, it might: (1) avoid feeding biomass into boiler, (2) reduce boiler fouling and corrosion problem, and (3) avoid altering ash characteristics. In this paper, CFD modeling of product gas (from biomass gasification) and coal co-firing in a 600 MW tangential PC boiler was carried out. The results showed that NO_x emission was reduced about 50–70% when the product gas was injected through the lowest layer burner. The fouling problem can be reduced with furnace temperature decreasing for co-firing case. The convection heat transfer area should be increased or the co-firing ratio of product gas should be decreased to keep boiler rated capacity.     

Indirectly heated biomass gasification using a latent heat ballast. Part 2: modeling

Experiments carried out in an indirectly heated biomass gasifier successfully demonstrated that throughput and gas heating value could be increased by using a latent heat ballast. A mathematical model describing heat transfer and chemical reaction in the system was developed. The heat transfer submodel is accurate to within 13 K for both ballasted and unballasted scenarios. However, the chemical submodel, based on thermodynamic equilibrium calculations, proved inadequate and underpredicted cooling times during the pyrolysis phase of the process by about 50%. Improvement was made by substituting the measured product gas composition for the calculated gas composition.     

通过清洁生产审核实现啤酒企业的节能降耗

啤酒生产中能源的消耗约占生产成本的10％。在开展啤酒企业清洁生产审核中,系统分析啤酒企业能源消耗状况,对比国内外先进工艺和技术,提出可以通过加强用能管理,采用麦汁一段冷却工艺、糖化热能回收、糖化热水回收、热电联供回收系统、沼气回收系统,以及在北方利用冬季室外风冷却系统的技术工艺,可以减少能源的消耗,达到节能、降耗、减污、增效的清洁生产目的。     

Thermodynamic analysis of a beer engine

This paper shows how the heat reclaimed from the exhaust gas of a gas turbine engine can be used to convert dilute ethyl alcohol (“beer”) to a fuel that can used to power the engine. Ordinarily, there is not enough heat available to distil the weak liquor to sufficient amounts of a strong product (>90%), due to high exergy destruction. In this design, a combination of destructive distillation and ordinary distillation is used, the wet product then being sent to a reformer for an endothermic shift reaction. The high temperature gas is now ready to burn in a gas turbine engine (or high temperature fuel cell). Water in the low temperature stack gas can be reclaimed in a cooling tower, if desired, so as to have no net loss of water for the system. The exergetic (Second Law) efficiency for power production is nearly 50%.     

Exergy analysis and optimization of a biomass gasification, solid oxide fuel cell and micro gas turbine hybrid system

A hybrid plant producing combined heat and power (CHP) from biomass by use of a two-stage gasification concept, solid oxide fuel cells (SOFC) and a micro gas turbine was considered for optimization. The hybrid plant represents a sustainable and efficient alternative to conventional decentralized CHP plants. A clean product gas was produced by the demonstrated two-stage gasifier, thus only simple gas conditioning was necessary prior to the SOFC stack. The plant was investigated by thermodynamic modeling combining zero-dimensional component models into complete system-level models. Energy and exergy analyses were applied. Focus in this optimization study was heat management, and the optimization efforts resulted in a substantial gain of approximately 6% in the electrical efficiency of the plant. The optimized hybrid plant produced approximately 290 kW_e at an electrical efficiency of 58.2% based on lower heating value (LHV).     

Studies on the energy demand of two-stage fermentative hydrogen production from biomass in a factory equipped with fuel-cell based power plant

A conceptual factory to produce hydrogen from starchy biomass is considered. The production plant comprises a pretreatment unit for starchy raw material, a bioreactor for dark fermentation, a photobioreactor for photofermentation and gas upgrading & compression units, and is supplied with the necessary heat and power from the power plant. In the power plant, a part of the stream of raw gas produced in bioreactors is burned in a steam boiler and in addition some product gas from the upgrading unit is directed to fuel cells from which waste gas flows to a catalytic oxidizer. The demand for process heat is covered by steam generation in the boiler and oxidizer, and the power demand is covered by electricity generation in the fuel cells.     

Optimization of hydrogen production by Chemical-Looping auto-thermal Reforming working with Ni-based oxygen-carriers

Chemical-Looping auto-thermal Reforming (CLRa) is a new process for hydrogen production from natural gas that uses the same principles as Chemical-Looping Combustion (CLC). The main difference with CLC is that the desired product is syngas (H₂ + CO) instead of CO₂ + H₂O. For that, in the CLRa process the air-to-fuel ratio is kept low to prevent the complete oxidation of the fuel. The major advantage of this technology is that the heat needed for converting CH₄ to syngas is supplied without costly oxygen production and without mixing of air with carbon containing fuel gases.An important aspect to be considered in the design of a CLRa system is the heat balance. In this work, mass and heat balances were done to determine the auto-thermal operating conditions that maximize H₂ production in a CLRa system working with Ni-based oxygen-carriers. It was assumed that the product gas was in thermodynamic equilibrium at the exit of the air- and fuel-reactors and the equilibrium gas compositions were obtained by using the method of minimization of the Gibbs free energy of the system. It was found that to reach auto-thermal conditions the oxygen-to-methane molar ratio should be higher than 1.20, which means that the maximum H₂ yield is about 2.75 mol H₂/mol CH₄. The best option to control the oxygen-to-methane molar ratio is to control the air flow fed to the air-reactor because a lower air excess is needed to reach auto-thermal conditions.