生物质能利用技术的研究及发展

我国的生物质能资源主要是农业废弃物、禽畜类便和林业废弃物。生物质能的利用方式有：直接燃烧、产生沼气等可燃气、发电、转化为液体燃料和加工成高密度的固体燃料。文中对几种利用方式进行了讨论。

生物质气化与废弃物焚烧联合发电的技术经济分析

介绍了生物质气化与废弃物焚烧联合发电技术项目，确定了该项目经济效益的评价指标，定量计算了项目的投资回收期、净现值和内部收益率。同时还对燃料费用、上网电价和固定资产变化引起的敏感性进行分析。结果表明，该联合发电技术的动态投资回收期为9.05a，净现值为2770万元，内部收益率为15.82％，三个经济指标均符合行业标准。从经济角度看是完全可行的。

Design and Operation of A 5.5 MWe Biomass Integrated Gasification Combined Cycle Demonstration Plant

The design and operation of a 5.5 MWe biomass integrated gasification combined cycle (IGCC) demonstration plant, which is located in Xinghua, Jiangsu Province of China, are introduced. It is the largest complete biomass gasification power plant that uses rice husk and other agricultural wastes as fuel in Asia. It mainly consists of a 20 MWt atmospheric circulating fluidized-bed gasifier, a gas-purifying system, 10 sets of 450 kW(e) gas engines, a waste heat boiler, a 1.5 MWe steam turbine, a wastewater treatment system, etc. The demonstration plant has been operating since the end of 2005, and its overall efficiency reaches 26-28%. Its capital cost is less than 1200 USD/kW, and its running cost is about 0.079 USD/kWh based on the biomass price of 35.7 USD/ton. There is a 20% increment on capital cost and 35% decrease on the fuel consumption compared to that of a 1 MW system without a combined cycle. Because only part of the project has been performed, many of the tests still remain and, accordingly, must be reported at a later opportunity.

High electrical-to-green efficiency high stability intracavity-frequency-doubled Nd:YAG-LBO QCW 532 nm laser with a straight cavity

An electrical-to-green efficiency of more than 10% was demonstrated by intracavity-frequency-doubling a Q-switched diode-side-pumped Nd:YAG laser with a type II lithium triborate (LBO) crystal in a straight plano-concave cavity. An average power of 69.2 W at 532 nm was generated when electrical input power was 666 W. The corresponding electrical-to-green conversion efficiency is 10.4%. To the best of our knowledge, this is the highest electrical-to-green efficiency of second harmonic generation laser systems with side-pumped laser modules, ever reported. At about 66 W of green output power, the power fluctuation over 4 hours was better than +/-0.86%.

Mixed reforming of heptane to syngas in the Ba0.5Sr0.5Co0.8Fe0.2O3 membrane reactor

Fuel cells are recognized as the most promising new power generation technology, but hydrogen supply is still a problem. In our previous work, we have developed a LiLaNiO/gamma-Al2O3 catalyst, which is excellent not only for partial oxidation of hydrocarbons, but also for steam reforming and autothermal reforming. However, the reaction needs pure oxygen or air as oxidant. We have developed a dense oxygen permeable membrane Ba0.5Sr0.5Co0.8Fe0.2O3 which has an oxygen permeation flux around 11.5 ml/cm(2) min at reaction conditions. Therefore, this work is to combine the oxygen permeable membrane with the catalyst LiLaNiO/gamma-Al2O3 in a membrane reactor for hydrogen production by mixed reforming of heptane. Under optimized reaction conditions, a heptane conversion of 100%, a CO selectivity of 91-93% and a H-2 selectivity of 95-97% have been achieved. (c) 2005 Elsevier B.V. All rights reserved.

Tecnologias CAC e Inquéritos de Percepção da Opinião Pública sobre “O papel da Captação e do Armazenamento/Sequestração de Dióxido de Carbono no Futuro da Energia na Europa”:O caso-de-estudo da Comunidade Fernando Pessoa

O carvão e outros combustíveis fósseis, continuarão a ser, por décadas, a principal matéria-prima energética para as Centrais Térmicas, não obstante os esforços para, dentro do possível, substituir os combustíveis fósseis por fontes de energia renovável.Tal como está, hoje, bem documentado, a produção de gases com efeito estufa (GEE), designadamente CO2, resulta da combustão dos ditos combustíveis fósseis, sendo que se espera ser possível mitigar substancialmente a emissão de tais gases com a aplicação das chamadas Tecnologias Limpas do Carvão.Há, pois, necessidade de promover o abatimento do CO2 através de Tecnologias de Emissão Zero ou Tecnologias Livres de Carbono, incluindo designadamente a Captura, o Transporte e a Sequestração geológica de CO2 correspondentes ao que é costume designar por Tecnologias CAC (Captação e Armazenamento de Carbono). De facto, tais tecnologias e, designadamente, o armazenamento geológico de CO2 são as únicas que, no estado actual do conhecimento, são capazes de permitir que se cumpram as metas do ambicioso programa da EU para a energia e o ambiente conhecido por “20 20 para 2020” em conjugação com os aspectos económicos das directivas relativas ao Comércio Europeu de Licenças de Emissão – CELE (Directivas 2003/87/EC, 2004/101/EC e 2009/29/EC).A importância do tema está, aliás, bem demonstrada com o facto da Comissão Europeia ter formalmente admitido que as metas supracitadas serão impossíveis de atingir sem Sequestração Geológica de CO2. Esta é, pois, uma das razões de ter sido recentemente publicada a Directiva Europeia 2009/31/EC de 23 de Abril de 2009 expressamente dedicada ao tema do Armazenamento Geológico de CO2.Ora, a questão do armazenamento geológico de CO2 implica, para além das Tecnologias CAC acima mencionadas e da sua viabilização em termos tanto técnicos como económicos, ou seja, neste último aspecto, competitiva com o sistema CELE, também o conhecimento, da percepção pública sobre o assunto. Isto é, a praticabilidade das Tecnologias CAC implica que se conheça a opinião pública sobre o tema e, naturalmente, que face a esta realidade se prestem os esclarecimentos necessários como, aliás, é reconhecido na própria Directiva Europeia 2009/31/EC.Dado que a Fundação Fernando Pessoa / Universidade Fernando Pessoa através do seu Centro de Investigação em Alterações Globais, Energia, Ambiente e Bioengenharia – CIAGEB tem ultimado um Projecto de Engenharia relativo à Sequestração Geológica de CO2 nos Carvões (Metantracites) da Bacia Carbonífera do Douro – o Projecto COSEQ, preocupou-se naturalmente, desde o início, com o lançamento de inquéritos de percepção da opinião pública sobre o assunto.Tal implicou, nesta fase, a tradução para português e o lançamento do inquérito europeu ACCSEPT que não tinha sido ainda formalmente lançado de forma generalizada entre nós. Antes, porém, de lançar publicamente tal inquérito – o que está actualmente já em curso – resolveu-se testar o método de lançamento, a recolha de dados e o seu tratamento com uma amostra correspondente ao que se designou por Comunidade Fernando Pessoa, i.e. o conjunto de docentes, discentes, funcionários e outras pessoas relacionadas com a Universidade Fernando Pessoa (cerca de 5000 individualidades).Este trabalho diz, precisamente, respeito à preparação, lançamento e análise dos resultados do dito inquérito Europeu ACCSEPT a nível da Comunidade Fernando Pessoa. Foram recebidas 525 respostas representando 10,5% da amostra. A análise de resultados foi sistematicamente comparada com os obtidos nos outros países europeus, através do projecto ACCSEPT e, bem assim, com os resultados obtidos num inquérito homólogo lançado no Brasil. The use of coal, and other fossil fuels, will remain for decades as the main source of energy for power generation, despite the important efforts made to replace, as far as possible, fossil fuels with renewable power sources.As is well documented, the production of Greenhouse Gases (GHG), mainly CO2, arises primarily from the combustion of fossil fuels. The increasing application of Clean Coal Technologies-CCTs, is expected to mitigate substantially against the emission of such gases.There is consequently a need to promote the CO2 abatement through Zero Emission (Carbon Free) Technologies - ZETs, which includes CO2 capture, transport and geological storage, i.e. the so-called CCS (Carbon, Capture and Storage) technologies. In fact, these technologies are the only ones that are presently able to conform to the ambitious EU targets set out under the “20 20 by 2020” EU energy and environment programme, jointly with the economic aspects of the EU Directives 2003/87/EC, 2004/101/EC and 2009/29/EC concerned with the Greenhouse Gas Emissions Allowance Trading Scheme – ETS scheme. The European Commission formal admission that the referred targets will be impossible to reach without the implementation and contribution of geological storage clearly demonstrate the importance of this particular issue, and for this reason the EC Directive 2009/31/EC of April 23, 2009 on Geological Storage of CO2 was recently published.In considering the technical and economical viabilities of CCS technologies, the latter in competition with the ETS scheme, it is believed that public perception will dictate the success of the development and implementation of CO2 geological storage at a large industrial level. This means that, in order to successfully implement CCS technologies, not only must public opinion be taken into consideration but objective information must also be provided to the public in order to raise subject awareness, as recognized in the referred Directive 2009/31/EC.In this context, the Fernando Pessoa Foundation / University Fernando Pessoa, through its CIAGEB (Global Change, Energy, Environment and Bioengineering) RDID&D Unit, is the sponsor of an Engineering Project for the Geological Sequestration of CO2 in Douro Coalfield Meta-anthracites - the COSEQ Project, and is therefore also engaged in public perception surveys with regards to CCS technologies.At this stage, the original European ACCSEPT inquiry was translated to Portuguese and submitted only to the “Fernando Pessoa Community” - comprising university lecturers, students, other employees, as well as, former students and persons that have a professional or academic relationship with the university (c. 5000 individuals). The results obtained from this first inquiry will be used to improve the survey informatics system in terms of communication, database, and data treatment prior to resubmission of the inquiry to the Portuguese public at large.The present publication summarizes the process and the results obtained from the ACCSEPT survey distributed to the “Fernando Pessoa Community”. 525 replies, representing 10.5% of the sample, have been received and analysed. The assessment of the results was systematically compared with those obtained from other European Countries, as reported by the ACCSEPT inquiry, as well as with those from an identical inquiry launched in Brazil.

Electrical machine characterisation and analysis for renewable energy applications

There has been an increased use of the Doubly-Fed Induction Machine (DFIM) in ac drive applications in recent times, particularly in the field of renewable energy systems and other high power variable-speed drives. The DFIM is widely regarded as the optimal generation system for both onshore and offshore wind turbines and has also been considered in wave power applications. Wind power generation is the most mature renewable technology. However, wave energy has attracted a large interest recently as the potential for power extraction is very significant. Various wave energy converter (WEC) technologies currently exist with the oscillating water column (OWC) type converter being one of the most advanced. There are fundemental differences in the power profile of the pneumatic power supplied by the OWC WEC and that of a wind turbine and this causes significant challenges in the selection and rating of electrical generators for the OWC devises. The thesis initially aims to provide an accurate per-phase equivalent circuit model of the DFIM by investigating various characterisation testing procedures. Novel testing methodologies based on the series-coupling tests is employed and is found to provide a more accurate representation of the DFIM than the standard IEEE testing methods because the series-coupling tests provide a direct method of determining the equivalent-circuit resistances and inductances of the machine. A second novel method known as the extended short-circuit test is also presented and investigated as an alternative characterisation method. Experimental results on a 1.1 kW DFIM and a 30 kW DFIM utilising the various characterisation procedures are presented in the thesis. The various test methods are analysed and validated through comparison of model predictions and torque-versus-speed curves for each induction machine. Sensitivity analysis is also used as a means of quantifying the effect of experimental error on the results taken from each of the testing procedures and is used to determine the suitability of the test procedures for characterising each of the devices. The series-coupling differential test is demonstrated to be the optimum test. The research then focuses on the OWC WEC and the modelling of this device. A software model is implemented based on data obtained from a scaled prototype device situated at the Irish test site. Test data from the electrical system of the device is analysed and this data is used to develop a performance curve for the air turbine utilised in the WEC. This performance curve was applied in a software model to represent the turbine in the electro-mechanical system and the software results are validated by the measured electrical output data from the prototype test device. Finally, once both the DFIM and OWC WEC power take-off system have been modeled succesfully, an investigation of the application of the DFIM to the OWC WEC model is carried out to determine the electrical machine rating required for the pulsating power derived from OWC WEC device. Thermal analysis of a 30 kW induction machine is carried out using a first-order thermal model. The simulations quantify the limits of operation of the machine and enable thedevelopment of rating requirements for the electrical generation system of the OWC WEC. The thesis can be considered to have three sections. The first section of the thesis contains Chapters 2 and 3 and focuses on the accurate characterisation of the doubly-fed induction machine using various testing procedures. The second section, containing Chapter 4, concentrates on the modelling of the OWC WEC power-takeoff with particular focus on the Wells turbine. Validation of this model is carried out through comparision of simulations and experimental measurements. The third section of the thesis utilises the OWC WEC model from Chapter 4 with a 30 kW induction machine model to determine the optimum device rating for the specified machine. Simulations are carried out to perform thermal analysis of the machine to give a general insight into electrical machine rating for an OWC WEC device.

Feasibility of combined wind-wave energy platforms

The European Union has set out an ambitious 20% target for renewable energy use by 2020. It is expected that this will be met mainly by wind energy. Looking towards 2050, reductions in greenhouse gas emissions of 80-95% are to be sought. Given the issues securing this target in the transport and agriculture sectors, it may only be possible to achieve this target if the power sector is carbon neutral well in advance of 2050. This has permitted the vast expansion of offshore renewables, wind, wave and tidal energy. Offshore wind has undergone rapid development in recent years however faces significant challenges up to 2020 to ensure commercial viability without the need for government subsidies. Wave energy is still in the very early stages of development so as yet there has been no commercial roll out. As both of these technologies are to face similar challenges in ensuring they are a viable alternative power generation method to fossil fuels, capitalising on the synergies is potentially a significant cost saving initiative. The advent of hybrid solutions in a variety of configurations is the subject of this thesis. A singular wind-wave energy platform embodies all the attributes of a hybrid system, including sharing space, transmission infrastructure, O&M activities and a platform/foundation. This configuration is the subject of this thesis, and it is found that an OWC Array platform with multi-MegaWatt wind turbines is a technically feasible, and potentially an economically feasible solution in the long term. Methods of design and analysis adopted in this thesis include numerical and physical modelling of power performance, structural analysis, fabrication cost modelling, simplified project economic modelling and time domain reliability modelling of a 210MW hybrid farm. The application of these design and analysis methods has resulted in a hybrid solution capable of producing energy at a cost between €0.22/kWh and €0.31/kWh depending on the source of funding for the project. Further optimisation through detailed design is expected to lower this further. This thesis develops new and existing methods of design and analysis of wind and wave energy devices. This streamlines the process of early stage development, while adhering to the widely adopted Concept Development Protocol, to develop a technically and economically feasible, combined wind-wave energy hybrid solution.

A COMPARISON OF MARKET CLEARING TOOLS IN ELECTRICITY SYSTEMS

To maintain a strict balance between demand and supply in the US power systems, the Independent System Operators (ISOs) schedule power plants and determine electricity prices using a market clearing model. This model determines for each time period and power plant, the times of startup, shutdown, the amount of power production, and the provisioning of spinning and non-spinning power generation reserves, etc. Such a deterministic optimization model takes as input the characteristics of all the generating units such as their power generation installed capacity, ramp rates, minimum up and down time requirements, and marginal costs for production, as well as the forecast of intermittent energy such as wind and solar, along with the minimum reserve requirement of the whole system. This reserve requirement is determined based on the likelihood of outages on the supply side and on the levels of error forecasts in demand and intermittent generation. With increased installed capacity of intermittent renewable energy, determining the appropriate level of reserve requirements has become harder. Stochastic market clearing models have been proposed as an alternative to deterministic market clearing models. Rather than using a fixed reserve targets as an input, stochastic market clearing models take different scenarios of wind power into consideration and determine reserves schedule as output. Using a scaled version of the power generation system of PJM, a regional transmission organization (RTO) that coordinates the movement of wholesale electricity in all or parts of 13 states and the District of Columbia, and wind scenarios generated from BPA (Bonneville Power Administration) data, this paper explores a comparison of the performance between a stochastic and deterministic model in market clearing. The two models are compared in their ability to contribute to the affordability, reliability and sustainability of the electricity system, measured in terms of total operational costs, load shedding and air emissions. The process of building the models and running for tests indicate that a fair comparison is difficult to obtain due to the multi-dimensional performance metrics considered here, and the difficulty in setting up the parameters of the models in a way that does not advantage or disadvantage one modeling framework. Along these lines, this study explores the effect that model assumptions such as reserve requirements, value of lost load (VOLL) and wind spillage costs have on the comparison of the performance of stochastic vs deterministic market clearing models.

Prospect for EPM application to environmental technology

EPM seems to have good prospects for the future not only in the materials processing but also in environmental technologies by the help of superior features like contactless processing, clean heating and melting, and good controllability. In the present paper, the authors commentate on the possibility of EPM to avoid environmental issues of energy, resources and hazardous wastes by the use of the functions of Lorentz force and Joule heating. Firstly, the present situation and future trend of electric power generation is outlined, and then some examples of the application of EPM to environmental technologies are introduced, which have been performed by the author’s group. Examples are as follows: production of spherical solar cell from a liquid jet by using intermittent electromagnetic force; fabrication of semi-solid Al-Si slurry for die-casting of vehicle-parts to reduce the weight of vehicle; electromagnetic separation of nonmetallic inclusions from liquid Al scrap and its application to the fabrication of partially particle-reinforced aluminum alloy; electromagnetic melting of hazardous wastes from power plants to stabilize wastes in glass state.

Detection and impacts of leakage from sub-seafloor deep geological carbon dioxide storage

Fossil fuel power generation and other industrial emissions of carbon dioxide are a threat to global climate1, yet many economies will remain reliant on these technologies for several decades2. Carbon dioxide capture and storage (CCS) in deep geological formations provides an effective option to remove these emissions from the climate system3. In many regions storage reservoirs are located offshore4, 5, over a kilometre or more below societally important shelf seas6. Therefore, concerns about the possibility of leakage7, 8 and potential environmental impacts, along with economics, have contributed to delaying development of operational CCS. Here we investigate the detectability and environmental impact of leakage from a controlled sub-seabed release of CO2. We show that the biological impact and footprint of this small leak analogue (<1 tonne CO2 d−1) is confined to a few tens of metres. Migration of CO2 through the shallow seabed is influenced by near-surface sediment structure, and by dissolution and re-precipitation of calcium carbonate naturally present in sediments. Results reported here advance the understanding of environmental sensitivity to leakage and identify appropriate monitoring strategies for full-scale carbon storage operations.

Detection and impacts of leakage from sub-seafloor deep geological carbon dioxide storage

Fossil fuel power generation and other industrial emissions of carbon dioxide are a threat to global climate1, yet many economies will remain reliant on these technologies for several decades2. Carbon dioxide capture and storage (CCS) in deep geological formations provides an effective option to remove these emissions from the climate system3. In many regions storage reservoirs are located offshore4, 5, over a kilometre or more below societally important shelf seas6. Therefore, concerns about the possibility of leakage7, 8 and potential environmental impacts, along with economics, have contributed to delaying development of operational CCS. Here we investigate the detectability and environmental impact of leakage from a controlled sub-seabed release of CO2. We show that the biological impact and footprint of this small leak analogue (<1 tonne CO2 d−1) is confined to a few tens of metres. Migration of CO2 through the shallow seabed is influenced by near-surface sediment structure, and by dissolution and re-precipitation of calcium carbonate naturally present in sediments. Results reported here advance the understanding of environmental sensitivity to leakage and identify appropriate monitoring strategies for full-scale carbon storage operations.

The investigation of mechanisms in environmental catalysis using time-resolved methods

The formation of nitrogen oxides (NOx) during a combustion process is difficult to avoid because of the large exotherm and the consequent problem of avoiding local high-temperature spikes. Consequently, for many applications, such as for automotive power generation, there will be a continuing need to use catalytic after-treatment to reduce harmful emissions. The investigation of the mechanisms of the key catalytic reactions in environmental catalysis can provide an insight into the action of the catalyst, and time-resolved methods offer a powerful means to study these processes under realistic conditions. The use of Temporal Analysis of Products (TAP) and Steady State Isotopic Transient Kinetic Analysis (SSITKA) methods to investigate the reduction of NOx under various experimental conditions is described. From a detailed analysis of the SSITKA profiles, it is shown that at low temperatures the mechanism for the formation of N-2 and N2O from NO may differ from the conventional high-temperature mechanism. This is supported by density functional theory calculations, which show that the barrier to the formation of N2O from the reaction of N(ads) and NO(ads) may be too high to allow this process to occur at low temperatures. The alternative reaction of NO(ads) + NO(ads) = N2O(g) + O(ads) is shown to be much more favorable and is consistent with the SSITKA analysis. The remarkable effect of hydrogen as a reductant at low temperatures is described, and alternative interpretations of the role of hydrogen are discussed.

Current transients in the small salient-pole alternator caused by sudden short-circuit and synchronisation events

Small salient-pole machines, in the range 30 kVA to 2 MVA, are often used in distributed generators, which in turn are likely to form the major constituent of power generation in power system islanding schemes or microgrids. In addition to power system faults, such as short-circuits, islanding contains an inherent risk of out-of-synchronism re-closure onto the main power system. To understand more fully the effect of these phenomena on a small salient-pole alternator, the armature and field currents from tests conducted on a 31.5 kVA machine are analysed. This study demonstrates that by resolving the voltage difference between the machine terminals and bus into direct and quadrature axis components, interesting properties of the transient currents are revealed. The presence of saliency and short time-constants cause intriguing differences between machine events such as out-of-phase synchronisations and sudden three-phase short-circuits.

Modelling gas storage with compressed air energy storage in a system with large wind penetrations

Installed wind capacity in the European Union is expected to continue to increase due to renewable energy targets and obligations to reduce greenhouse gas emissions. Renewable energy sources such as wind power are variable sources of power. Energy storage technologies are useful to manage the issues associated with variable renewable energy sources and align non-dispatchable renewable energy generation with load demands. Energy storage technologies can play different roles in electric power systems and can be used in each of the steps of the electric power supply chain. Moreover, large scale energy storage systems can act as renewable energy integrators by smoothening the variability of large penetrations of wind power. Compress Air Energy Storage is one such technology. The aim of this paper is to examine the technical and economic feasibility of a combined gas storage and compressed air energy storage facility in the all-island Single Electricity Market of Northern Ireland and the Republic of Ireland in order to optimise power generation and wind power integration. This analysis is undertaken using the electricity market software PLEXOS ® for power systems by developing a model of a combined facility in 2020.