Optimization of Improvable Flows by combining BAT Analysis and process simulation

This paper proposes a methodology to improve the sustainability of industrial processes combining two tools: BAT Analysis and process simulation. Both tools are jointly applied to identify the IF of the analyzed process, so that the most appropriate candidate techniques from an inventory can be selected. The selected alternatives are tested in different scenarios that are evaluated using simulation, which would determine the configuration that best improves the sustainability of the process. The combination of both tools in an integrated methodology will help decision makers to select the most sustainable configuration for a given process. The methodology is validated in a case study: a hydrogen production plant. After analysing several scenarios where different candidate techniques are implemented, results show that the IF identified can be highly improved when the appropriate combination of BAT is applied.     

Integrated characteristics and performance of zero emission coal system

Before the commercialization of zero emission coal (ZEC), some technical hurdles must be settled and the performance of the whole system needs to be studied. The main technical hurdles of ZEC system are analyzed and some solutions are presented in this paper. A detailed ZEC system is setup and its characteristics are studied. High temperature solid oxide fuel cell (SOFC) is used to produce electricity and served as the heat source for the decarbonater. ZnO and NaHCO₃ are proposed to deeply eliminate H₂S and HCl. H₂ recycle ratio should be kept at 0.75 for the high conversion ratio of carbon in the gasifier and the high system efficiency. Calcium to carbon mole ratio (CTCR) should be kept around 0.6 to reach high CO₂ sequestration rate and acceptable economic penalty. Fuel utilization factor (U_f) of SOFC should be kept around 0.55 so as to supply enough heat to the decarbonater, and steam to carbon ratio (STCR) for the reformers in the system should be kept around 2.0. With these optimized parameters, the total efficiency of the system of 69.1% and the CO₂ sequestration ratio of 87% can be reached.     

转化炉管完整性分析专家系统(RTIES)的设计

针对RTIES的3个组成部分──炉管剩余寿命综合预测系统、炉管故障诊断系统和炉管性能数据库和知识库系统，介绍了其基本组成及设计思想，重点是寿命综合预测系统及故障诊断系统．对微机在转化管的运行和管理上的应用作了有益的尝试．     

Comparison of steam and autothermal reforming of methanol using a packed-bed low-cost copper catalyst

Small-scale reformers for hydrogen production via steam and autothermal reforming of hydrocarbon feedstocks can be a solution to the lack of hydrogen distribution infrastructure. A packed-bed reactor is one possible design for such purpose. However, the two reforming processes of steam and autothermal methods have different characteristics, thus they have different and often opposite design requirements. In implementing control strategy for small-scale reformers, understanding the overall chemical reactions and the reactor physical properties becomes essential. This paper presents some inherent features of a packed-bed reactor that can both improve and/or degrade the performance of a packed-bed reactor with both reforming modes.The high thermal resistance of the packed bed is disadvantageous to steam reforming (SR), but it is beneficial to the autothermal reforming (ATR) mode with appropriate reactor geometry. The low catalyst utilization in steam reforming can help to prevent the unconverted fuel leaving the reactor during transient by allowing briefly for higher reactant fuel flow rates. In this study, experiments were performed using three reactor geometries to illustrate these properties and a discussion is presented on how to take advantages of these properties in reactor design.     

Fast and exergy efficient start-up of micro-solid oxide fuel cell systems by using the reformer or the post-combustor for start-up heating

The start-up process of a micro-solid oxide fuel cell system strongly influences its overall efficiency, especially for portable applications where a frequent switch-on and switch-off is required. We present herein a novel start-up process for such systems that exploits existing units, such as the post-combustor or the reformer, as a heat source to reach the operation temperature of the cell at 600 °C. Our experimental results show that the employment of platinum catalysts in the post-combustor or rhodium catalysts in the reformer for total oxidation of butane by air combined with an electrically heated wire led to a faster and more efficient start-up than conventional start-up methods using only electrical energy. By using the post-combustor as heat source, the start-up time could be reduced by 79% and the exergy cost by 86%. The latter includes the cost of the stand-alone fuel cell system to produce electrical energy for the joule heating of the wire (i.e. the system efficiency is accounted for). There are several advantages to use the reformer as heat source during start-up, such as prevention of coking of the fuel cell or improved heat transfer by internal heating of the other components. The start-up performance, however, was lower than that of the post-combustor: the start-up time could be reduced by 65% and the exergy cost by 68% compared to a conventional start-up.     

Numerical simulation on non-catalytic thermal process of methane reformation for hydrogen productions

The reformer that produces hydrogen from hydrocarbon is very important part of fuel cell system. One of the promising solutions has been recently considered as direct partial oxidation of hydrocarbon by excess enthalpy flame under rich and ultra-rich condition without a platinum catalyst. In this paper, excess enthalpy flame reforming process in the perforated silicon carbide tube reformer using a two dimensional approached with GRI mechanism 1.2 was investigated. The result shows that the stable excess enthalpy flame with temperature spike was observed in a perforated silicon carbide tube reformer under condition of higher equivalence ratio than rich flammability limit of methane. It is found that hydrogen rich gases could be produced through partial oxidation at very rich equivalence ratio by formation of excess enthalpy flame. The peak flame temperature of excess enthalpy flame was higher than the adiabatic flame temperature for a free laminar flame at identical conditions and excess enthalpy flame at ultra-rich equivalence ratio could become effective way to produce hydrogen rich gases from hydrocarbon. The conversion efficiency of hydrogen and carbon monoxide by partial oxidation of excess enthalpy flame was calculated as 37.64% and 60.62%, respectively at equivalence ratio of 2.0 and inlet velocity of 80 cm/s.     

大型转化炉转化管系统应力分析

随着化工装置大型化的发展趋势,装置内核心设备转化炉为了达到高产也相应做大,炉内的转化管数量也随之增加。庞大的转化管体系使得它的力学稳定性成为一个突出的问题,因此转化管系的应力分析也就显得尤为重要。文章针对一台超大型蒸汽转化炉的转化管系进行了应力分析,得出一些规律性结论,为今后该类炉型的详细设计起到一定的指导作用。     

Thermoneutral Design Aspects of Gasoline Chemical Looping Reformer

Chemical looping reforming (CLR) is a new technology for syngas generation. The theoretical process design aspects of syngas generation using CLR of isooctane (gasoline) are studied in this paper to assess its ability for fuel processor development for solid oxide fuel cells. The fuel processor operating conditions for maximum syngas generation at thermoneutral conditions are determined in this study using nickel oxide as oxygen carrier for different inputs of oxygen carrier within the temperature range of 600–1,000 °C at 1 bar pressure. The thermoneutral temperatures for the dual reactor fuel processor were calculated using the hot product gas stream and exothermic CLR process enthalpy to completely balance the endothermic process requirements. The thermoneutral point of 879.5 °C (NiO input of 7 moles) delivered maximum syngas (13.92 moles) using lowest amount of air (26.13 moles) in the process was found to be the most suitable thermoneutral temperature for the fuel processor operation. The novel fuel processor design can also be used for other fuels and oxygen carriers.     

高温气冷堆工艺热应用研究

介绍了高温气冷堆高温工艺热研究现状,分析了我国能源结构特点及核煤转化可行途径。结合８６３计划项目１０ＭＷ高温气冷堆即将建成,推出高温气冷堆高温工艺势应用研究方向,并介绍了１０ＭＷ高温气冷堆高温工艺热利用系统的设计及２．５ＭＷ氦加热重整器概念设计。