整体煤气化燃料电池联合发电(IGFC)技术研究进展

整体煤气化燃料电池联合发电技术(IGFC)是一种新型煤基洁净高效发电技术,不考虑热电联供的情况下,发电效率达60%以上,可有效控制污染物的排放,为CO₂捕集和回收创造了条件,可实现CO₂的近零排放。IGFC系统一般由煤气化净化、燃料电池发电、余热回收及CO₂捕集和封存等子系统构成,其中燃料电池发电技术是制约IGFC发展的关键技术。固体氧化物燃料电池(SOFC)及熔融碳酸盐燃料电池(MCFC)是适配IGFC系统的2种燃料电池技术,其中SOFC在生产成本及发电效率方面更具优越性。2017年国家能源集团牵头,联合中国矿业大学(北京)、北京低碳清洁能源研究院、华能清洁能源技术研究院、清华大学等,在国家重点研发计划项目支持下承担了开发100 kW级SOFC和MCFC发电单元,建成MW_th级CO₂近零排放的IGFC示范工程任务,项目成果推动了我国IGFC系统从基础技术研发向产业化迈进的步伐。     

Performance improvement of integrated coal gasification combined cycle by a new approach in exergy analysis

A new approach to exergy analysis is proposed for examing the consumption of energy as the minimum driving force and of exergy consumption that is avoidable, and for the development of a method to predict the alternatives in system improvement by exploring possible reduction in the avoidable exergy consumption. Also suggested in this study is a dimensionless parameter γ_AVO, which is the ratio of avoidable exergy consumption over total fuel energy input to the system. Detailed analyses, including the calculation of exergy consumption, exergy loss and avoidable exergy consumption, were conducted for each component in the syngas cooling system in the Integrated coal Gasification Combined Cycle (IGCC) plant, to prove the effective application of the proposed method. The analysis showed that the rank of avoidable exergy consumption was different from that of total energy consumption, and hence it confirmed that an energy analysis by conventional methods misled the focus of improvement in system design. The methodology developed in this study offers a new approach for system designers to analyze and to improve the performance of a complex energy system such as an IGCC plant.     

Ni载体整体煤气化链式燃烧联合循环性能

本文将具有分离CO₂的链式燃烧技术与整体煤气化联合循环(IGCC)技术结合,构成整体煤气化链式燃烧联合循环系统,对系统性能进行了模拟研究。结果表明,采用德士古气化工艺、空气反应器出口温度1200℃,NiO/NiAl₂O₄作载氧体,压气机压比17、补燃后透平初温(TIT)1350℃、冷却空气量12％时,系统净效率39.61% HHV（41.55%LHV）,CO₂排放量126 g·kW^-1·h^-1。补燃温度1350℃,空气反应器温度由1000℃升高到1200℃,CO₂的回收率提高约23％,系统效率由40.3%降低到39.61％;补燃温度由1200℃提高到1500℃,系统净效率由37.4%增加到40.8%,CO₂的排放量从3g·kW^-1·h^-1增加到202 g·kW^-1·h^-1;补燃温度一定,压比增大,系统比功减小,CO₂排放量增加,效率先增大后减小,存在最佳压比.     

Sustainable fuel cell integrated membrane desalination systems

According to the United Nations, between two and seven billion people will face water shortages by the year 2050. Further, it is estimated that the amount of water available per person will shrink by a third during the next two decades. Inadequate supply of good-quality water coupled with higher water demand due to rapid population growth and industrialisation in developing countries are among the major reasons for the worsening water situation. Current shortages of potable water around the world and looming water scarcity especially in the developing countries is the driving force behind the implementation of membrane technologies for seawater and brackish water desalination. Typical energy consumption in seawater reverse osmosis (RO) plants operating at 40–45% product water recovery and with energy recovery from the high pressure reject stream currently is about 3–4 kWh/m³. The near-term goal of the industry is to reduce energy consumption to less than 2 kWh/m³ by using a combination of energy efficient RO pumps, more efficient energy recovery devices, high performance low energy RO membranes, hybrid membrane systems, advanced pretreatment technologies and alternate energy integrated membrane systems. The beneficial aspects of using alternate energy systems such as on-site distributed fuel cell systems integrated with membrane desalination units in remote locations are discussed.     

Combination of thermochemical recuperative coal gasification cycle and fuel cell for power generation

An integrated power generation cycle combining thermochemical recuperation, brown coal gasification and a solid oxide fuel cell (SOFC) was proposed based on the concept of thermochemical recuperative energy. Process simulation combining the coal gasifier, gas turbine cycle, and SOFC module was conducted using the ASPEN Plus process simulation tool. The simulation indicated that the cycle efficiency increases from 39.5% (HHV) without the SOFC to about 45% (HHV) with the SOFC.     

Cost of energy analysis of integrated gasification combined cycle (IGCC) power plant with respect to CO2 capture ratio under climate change scenarios

This paper presents the results of the cost of energy (COE) analysis of an integrated gasification combined cycle (IGCC) power plant with respect to CO₂ capture ratio under the climate change scenarios. To obtain process data for a COE analysis, simulation models of IGCC power plants and an IGCC with carbon capture and sequestration (CCS) power plant, developed by the United States Department of Energy (DOE) and National Energy Technology Laboratory (NETL), have been adopted and simulated using Aspen Plus. The concept of 20-year levelized cost of energy (LCOE), and the climate change scenarios suggested by International Energy Agency (IEA) are also adopted to compare the COE of IGCC power plants with respect to CO₂ capture ratio more realistically. Since previous studies did not consider fuel price and CO₂ price changes, the reliability of previous results of LCOE is not good enough to be accepted for an economic comparison of IGCC power plants with respect to CO₂ capture ratio. In this study, LCOEs which consider price changes of fuel and CO₂ with respect to the climate change scenarios are proposed in order to increase the reliability of an economic comparison. And the results of proposed LCOEs of an IGCC without CCS power plant and IGCC with CCS (30%, 50%, 70% and 90% capture-mole basis- of CO₂ in syngas stream) power plants are presented.     

Bench-scale production of liquid fuel from woody biomass via gasification

The bench-scale production of hydrocarbon liquid fuel was achieved from woody biomass via gasification. The daily production capacity of the biomass-to-liquid (BTL) plant used in this study was 7.8 L of hydrocarbon liquid from 48 kg of woody biomass (on a dry basis), corresponding to 0.05 barrels. The BTL process involved the following steps: oxygen-enriched air gasification of the woody biomass, wet and dry gas cleaning, gas compression, carbon dioxide removal, and the Fischer-Tropsch (FT) synthesis reaction. In the gasification step, oxygen-enriched air gasification was carried out using a downdraft fixed-bed gasifier. The content of oxygen, which acts as the gasifying agent, was increased from 21.0 to 56.7 vol%; maximum values of the conversion to gas on a carbon basis and cold gas efficiency-approximately 96 C-mol% and 87.8%, respectively-were obtained at an oxygen content of around 30 vol%. With the increased oxygen content, the concentrations of CO, H₂, and CO₂ increased from 22.8 to 36.5 vol%, from 16.8 to 28.1 vol%, and from 9.8 to 14.8 vol%, respectively, while that of N₂ decreased from 48.8 to 16.0 vol%. The feed gas for the FT synthesis reaction was obtained by passing the product gas from the gasification step through a scrubber, carbon dioxide removal tower, and desulfurization tower; its composition was 30.8 vol% CO, 25.2 vol% H₂, 0.9 vol% CO₂, 2.5 vol% CH₄, 40.6 vol% N₂, < 5 ppb H₂S, and < 5 ppb COS. The hydrocarbon fuel was synthesized in a slurry bed reactor using hexadecane as the solvent and a Co/SiO₂ catalyst. For hydrocarbons with carbon chain lengths of more than 5 carbon atoms (collectively referred to as C₅₊) in the liquid fuel, a selectivity of 87.5% was obtained along with a chain growth probability of 0.84 under the following conditions: 4 MPa, 280 to 340 °C, and a ratio of catalyst weight to feed gas rate (W/F) of 9.3 g·h/mol.     

Performance optimization of two-staged gasification system for woody biomass

The performance of a small-scale two-staged gasification system is reported. In this system wood chips are gasified with a fixed bed gasifier and then tar in the produced gas is reformed in a non-catalytic reformer, finally the production gas is used to generate electricity. In this system, the gasifying agents are high temperature air and steam supplied into the gasifier and the reformer. This paper reports on optimum gasification air ratio (defined as the ratio of the oxygen mole supplied into the gasifier to the oxygen mole required for complete combustion of biomass), reforming air ratio (defined as the ratio of the oxygen mole supplied in the reformer to the oxygen mole required for the complete combustion of biomass) and steam ratio (defined as the ratio of the steam mole supplied into the gasifier to the carbon mole in biomass supplied into the gasifier) for producing required gas supplied into a dual-fueled diesel engine. The results showed that, under optimum conditions, the higher heating value of the reformed gas was 3.9 MJ/m³_N; the cold gas efficiency (defined as the ratio of HHV reformed gas × reformed gas flow rate to HHV biomass × biomass feed rate) of the gasification system was 66%, and the gross thermal efficiency of the overall system was 27%.     

Experimental investigation into compression properties of integrated coal gasification combined cycle fly ashes on a ceramic filter

The compression properties of IGCC (integrated coal gasification combined cycle) fly ash cake on a ceramic filter were carefully investigated under well-controlled conditions. Overall cake porosity and pressure drop of dust cake of three different particles of geometric mean diameters of 3.7, 6.2, and 12.1 Μm, and dynamic shape factors of 1.37, 1.57 and 1.65, respectively, were investigated, at face velocities of 0.02-0.06 m/s. Overall cake porosity was strongly dependent on face velocity, mass load, and particle size. The expressions for overall cake porosity, considering the compression effect, and pressure drop across the dust cake were developed with good agreement with experimental results.     

生物质二氧化碳气化过程模拟分析

利用Aspen Plus软件对生物质二氧化碳气化流程进行了严格稳态模拟,模拟结果与实验数据吻合良好。在此模型基础上分别研究了CO2-O2,H2O-CO2和H2O-CO2-O23种组合气化剂的工艺特性,通过调节温度、氧气当量比、CO2/C(摩尔比)和H2O/C(摩尔比)4个影响生物质气化的参数,分析气体产率和冷煤气效率变化规律,从而获得最优流程优化参数。研究结果表明:随着温度升高,气体产率和冷煤气效率升高,1 000℃以后趋于平稳;随着氧气的增加气体产率和冷煤气效率降低,较低的混合气当量比下产生的合成气较为理想;二氧化碳增加,一氧化碳的产率和冷煤气效率大幅提高,氢气的产率几乎不变;随着水蒸汽的比例增加,氢气产率增加,一氧化碳和甲烷减少,冷煤气效率先减少再增加,并在0.1到0.15之间有最小值。     

Optimal design and integration of an air separation unit (ASU) for an integrated gasification combined cycle (IGCC) power plant with CO2 capture

The air separation unit (ASU) plays a key role in improving the efficiency, availability, and operability of an oxygen-fed integrated gasification combined cycle (IGCC) power plant. An optimal integration between the ASU and the balance of the plant, especially the gasifier and the gas turbine (GT), has significant potential for enhancing the overall plant efficiency. Considering the higher operating pressure of the GT, an elevated-pressure air separation unit (EP-ASU) is usually favored instead of the conventional low-pressure air separation units (LP-ASU). In addition, a pumped liquid oxygen (PLOX) cycle is usually chosen if the operating pressure of the gasifier is high. A PLOX cycle helps to improve plant safety and availability and to decrease the capital cost by reducing the size of the oxygen compressor or by eliminating it completely. However, the refrigeration lost in withdrawn liquid oxygen must be efficiently recovered. This paper considers five different configurations of an ASU with PLOX cycle and compares their power consumptions with an EP-ASU with a traditional gaseous oxygen (GOX) cycle. The study shows that an optimally designed EP-ASU with a PLOX cycle can have similar power consumption to that of an EP-ASU with GOX cycle in the case of 100% nitrogen integration. In the case of an IGCC with pre-combustion CO₂ capture, the lower heating value (LHV) of the shifted syngas, both on a mass and volumetric basis, is in between the LHV of the unshifted syngas from an IGCC plant and the LHV of natural gas, for which the GTs are generally designed. The optimal air integration in the case of a shifted syngas is found to be much lower than that of an unshifted syngas. This paper concurs with the existing literature that the optimal integration occurs when air extracted from the GT can be replaced with the nitrogen from the ASU without exceeding mass/volumetric flow limitations of the GT. Considering nitrogen and air integration between the ASU and the GT, this paper compares the power savings in an LP-ASU with a PLOX cycle to the power savings in an EP-ASU with GOX cycle and EP-ASU with PLOX cycle. The results show that an LP-ASU with a PLOX cycle has less power consumption if the nitrogen integration levels are less than 50-60%. In addition, a study is carried out by varying the concentration of nitrogen and steam in the fuel diluents to the GT while the NOx level was maintained constant. The study shows that when the nitrogen injection rate exceeds 50%, an EP-ASU with a PLOX cycle is a better option than an LP-ASU with a PLOX cycle. This paper shows that an optimal design and integration of an ASU with the balance of the plant can help to increase the net power generation from an IGCC plant with CO₂ capture.     

Hydrogen generation by catalytic gasification of motor oils in an integrated fuel processor

Catalytic gasification of waste motor oil (MO) for the generation of high purity of hydrogen and then integrated to a proton exchange membrane fuel cell (PEMFC) is economically and environmentally attractive. Thus, the objective of the present work was to investigate a MO catalytic gasification for generating high-purity hydrogen with 15 wt.% NiO/Al₂O₃ catalysts. In a lab-scale fixed-bed downdraft experimental approach, catalytic gasification of MO was accompanied by a substantial production of syngas at 760–900 K. From the XANES spectra, most of the Ni(II) reduced to Ni(0) was found in the MO catalytic gasification process. The EXAFS data also showed that the central Ni atoms have a Ni–O and a Ni–Ni with bond distances of 2.04 ± 0.05 Å and 2.48 ± 0.05 Å, respectively. In addition to over 85% of syngas generation, approximately 8.35 × 10⁵ kcal h⁻¹ of thermal energy was recovered and cold gas efficiency (CGE) was 77–84% when the catalytic gasifier was operated at O/C atomic ratios between 1.1 and 1.3. The proposed syngas production unit can be integrated in a fuel processor (e.g. PEMFC), in order to separate and purify the syngas to yield a 99.99% hydrogen stream. Moreover, cost or benefit analyses of MO catalytic gasifiers of 10- and 20-TPD (tons per day) were also performed.     

Environmental and economic analysis of methanol production process via biomass gasification

We have researched and simulated the BTL (biomass to liquid process) in which woody biomass is converted to transportation liquid fuels. In the present study, methanol (MeOH) was considered as a liquid fuel. The BTL-MeOH was designed and the environmental and economic analysis of the process was performed from the viewpoint of CO₂ emission and capital and operating costs. A case study focusing on heat and power resources was conducted. The result revealed that the process required an independent case of heat and power for CO₂ reduction; however, the cost of this was high due to the cogeneration with a steam turbine. Therefore, the introduction of a low-cost cogeneration, e.g., with a gas turbine, was required for commercialization.     

无人机用燃料电池系统性能分析

建立了无人机用质子交换膜燃料电池（PEMFC）动力系统性能随大气环境变化的数学模型,通过Matlab进行仿真,分析海拔高度对PEMFC系统运行状况和热力学性能的影响。结果显示: 随着高度的增加,系统输出电压、输出电功率及系统电效率呈下降趋势;当高度一定时,随着电流密度的增加,系统输出电功率有最大值,但电堆输出电压和系统输出电效率下降;氢气进气压力的增大使系统的输出电压、电功率和电效率逐渐增大;为了提高燃料电池系统在一定高度下的性能,需要选择合适的电流密度和较高的氢气进气压力。     

Performance of a coal gasification pilot plant with hot fuel gas desulfurization

A coal gasification pilot plant operation with hot fuel gas desulfurization (HGD) was performed taking two coals (Indonesian ABK and MSJ) that differ in their carbon and sulfur contents. A dry-feeding entrained-bed type gasifier was used for gasification with oxygen and capable of operating at 30 bar pressure and 1,550 °C. The HGD unit consisted of a transport desulfurizer, a bubbling regenerator and a multi-cyclone. Attention was focused on attaining high carbon conversion and cold gas efficiency in the entrained bed reactor and the sulfur removal efficiency of the hot fuel gas desulfurization unit. The optimum conditions for achieving high performance of the operation are reported.     

Liquid chemical looping gasification of biomass:Thermodynamic analysis on cellulose

Liquid chemical looping technology is an innovation of chemical looping conversion technology.Using liquid metal oxide as the oxygen carrier during gasification process could prolong the service life of oxy-gen carrier and improve the process efficiency.In this paper,based on Gibbs minimum free energy method,the thermodynamic characteristics of biomass liquid chemical looping gasification were studied.Cellulose and lignin,the main components of biomass,were taken as the research objects.Bismuth oxide and antimony oxide were selected as liquid oxygen carriers.The results showed that when the temper-ature increased from 600 ℃ to 900 ℃,the output of H2 and CO in the products of cellulose gasification increased from 0.5 and 0.3 kmol to 1.3 and 2.6 kmol respectively.Different ratios of oxygen carriers to gasification raw materials had the best molar ratio.The addition of steam in the system was beneficial to the increase of H2 content and the increase of H2/CO molar ratio.Bi2O3 and Sb2O3 with different mass ratios were used as mixed oxygen carriers.The simulation results showed that the gasification temper-ature of biomass with different mixed oxygen carriers had the same equilibrium trend products.It could be seen from the results of product distribution that the influence of the mixing ratio of Bi2O3 and Sb2O3 on gas product distribution could be neglected.These results could provide simulation reference and data basis for subsequent research on liquid chemical looping gasification.     

Performance of vanadium-oxygen redox fuel cell

A promising approach to improving the energy density of the all-vanadium redox flow battery while also saving on raw materials costs, is to eliminate the positive half-cell electrolyte and replace it with an air electrode to produce a hybrid vanadium–oxygen redox fuel cell (VOFC). This concept was initially proposed by Kaneko et al. in 1992 and first evaluated at the University of New South Wales by Menictas and Skyllas-Kazacos in 1997. In this project the performance of the VOFC over a range of temperatures and using different types of membranes and air electrode assemblies was evaluated. Despite early problems with the membrane electrode assemblies that saw separation of the membrane due to swelling and expansion during hydration, with improved fabrication techniques, this problem was minimized and it was possible to operate a 5-cell VOFC system for a total of over 100 h without any deterioration in its performance.     

Effect of air separation unit integration on integrated gasification combined cycle performance and NO<Subscript>x</Subscript> emission characteristics

Thermodynamic simulation method is developed and applied to analyze the performance and the NO_x emission characteristics of the IGCC (Integrated Gasification Combined Cycle) power plants coupled with ASU (Air Separation Unit). Simulations on IGCC power plants are made through combining the chemical process models for coal gasification and gas clean-up and the thermodynamic combined cycle model with NO_x prediction capability. With coal as feedstock of IGCC, the present study investigates and compares the power output, the overall efficiency and the NO_x emission characteristics of various IGCC plants at different ASU integration conditions in order to give the design criteria for efficient and environmental friendly IGCC configuration.     

一体式再生燃料电池性能

报道了反应条件对一体式再生燃料电池单体电池性能的影响,并对单体电池的极化特性和循环稳定性进行测试。结果表明：URFC单体电池表现出优异的电性能和良好的循环稳定性。双模式工作条件下,反应温度控制在60～70 ℃比较合适。在燃料电池模式下,提高氧气压力可以更显著的提高电池性能;在氢气相对湿度为100%条件下,氧气相对湿度对电池性能影响不大,当电流密度大于500 mA/cm²时,采用干态氧气和相对湿度为100%氧气时,电池性能趋于一致。