Lignocellulosic biomass as sustainable feedstock and materials for power generation and energy storage

Lignocellulosic biomass has attracted great interest in recent years for energy production due to its renewability and carbon-neutral nature.There are various ways to convert lignocellulose to gaseous,liquid and solid fuels via thermochemical,chemical or biological approaches.Typical biomass derived fuels include syngas,bio-gas,bio-oil,bioethanol and biochar,all of which could be used as fuels for furnace,engine,turbine or fuel cells.Direct biomass fuel cells mediated by various electron carriers provide a new direction of lignocellulose conversion.Various metal and non-metal based carriers have been screened for mediating the electron transfer from biomass to oxygen thus generating electricity.The power density of direct biomass fuel cells can be over 100 mW cm^(-2),which shows promise for practical applications.Lignocellulose and its isolated components,primarily cellulose and lignin,have also been paid considerable attention as sustainable carbonaceous materials for preparation of electrodes for supercapacitors,lithium-ion batteries and lithium-sulfur batteries.In this paper,we have provided a state-of-the-art review on the research progress of lignocellulosic biomass as feedstock and materials for power generation and energy storage focusing on the chemistry aspects of the processes.It was recommended that process integration should be performed to reduce the cost for thermochemical and biological conversion of lignocellulose to biofuels,while efforts should be made to increase efficiency and improve the properties for biomass fuelled fuel cells and biomass derived electrodes for energy storage.

Techno-Economic Analysis of Power Production by Using Waste Biomass Gasification

Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for electricity generation by using timber and wood waste (T & WW) gasification in Iceland. Different expenses were considered, like capital, installation, engineering, operation and maintenance costs and the interest rate of the investment. Regarding to revenues, they come from of the electricity sale and the fee paid by the Icelandic municipalities for waste collection and disposal. The economic feasibility was conducted based on the economic indicators of net present value (NPV) and discounted payback period (DPP), bringing together three different subgroups based on gasifier capacities, subgroup a: 50 kW, subgroup b: 100 kW and subgroup c: 200 kW. The results show that total cost increases as the implemented power is increased. This indicator varies from 1228.6 k€ for subgroups a to 1334.7 k€ for subgroups b and 1479.5 k€ for subgroups c. It is worth mentioning that NPV is positive for three subgroups and it grows as gasifier scale is extended. NPV is about 122 k€ (111,020 $), 1824 k€ (1,659,840 $) and 4392 k€ (3,996,720 $) for subgroups a, b and c, respectively. Moreover, DPP has an inversely proportional to the installed capacity. It is around 5.5 years (subgroups a), 9.5 months (subgroups b) and 6 months (subgroups c). The obtained results confirm that using small scale waste biomass gasification integrated with power generation could be techno-economically feasible for remote area in Iceland.

The status quo and prospect of biomass power generation in China

Facing the pressure of fossil energy exhaustion and environment pollution, people begin to search for clean and renewable energy to partly substitute fossil energy and realize sustainable development. As the fourth type of energy, biomass energy has many advantages: wide distribution, large quantity, being renewable, clean, storable and transportable and so on. By adopting thermo-chemical and biochemical technologies, biomass energy can be converted to high quality solid, liquid and gaseous energy products, and provide convenient heat and power energy for human being’s production and daily life. This paper presented the status quo of biomass power generation industry in China and also introduced briefly the future development models.

Focus on the Chicken Manure Power Generation in China: How to Promote the Biomass Waste Industry?

With the vigorous growth of animal husbandry, animal feces in the agriculture sector gradually deteriorate the environment. The chicken manure power generation is becoming viable and useful for energy conversion to comply with the context of environmental protection in China. Based on resource endowments and technical conditions, this paper studies the current situation of chicken manure power generation in China. Combined with the policy environment, the research conducts a PEST-SWOT matrix analysis to thoroughly look into the strengths and weaknesses, the opportunities and challenges. Then, the paper analyzes the distribution of chicken manure and gives some solutions from respects of government regulatory behavior, industrial-organizational behavior and corporation strategic behavior. Finally, it is concluded that: 1) the government should strengthen policy support by actively improving the subsidy mechanism and lowering the threshold of financing and credit;2) enterprises should focus on improving power generation technology and boiler treatment technology.

Biomass gasification technology:The state of the art overview

In the last decades the interest in the biomass gasification process has increased due to the growing attention to the use of sustainable energy. Biomass is a renewable energy source and represents a valid alternative to fossil fuels. Gasification is the thermochemical conversion of an organic material into a valuable gaseous product, called syngas, and a solid product, called char. The biomass gasification represents an efficient process for the production of power and heat and the production of hydrogen and second-generation biofuels.This paper deals with the state of the art biomass gasification technologies, evaluating advantages and disadvantages, the potential use of the syngas and the application of the biomass gasification. Syngas cleaning though fundamental to evaluate any gasification technology is not included in this paper since; in the authors＇ opinion, a dedicated review is necessary.

Study on Biomass Gasified Generator Using Rotary Engine

The purpose of this study is to investigate the biomass gasification system for power supply to introduce in rural communities of developing countries.The study was conducted using biomass gasification system(20 kW)which developed at Ashikaga University.In general,for small scale power supply system using biomass gasification,reciprocate type engine or modified diesel engine are attached for power generation.However,biomass gasifier produces tar and it causes problems on smooth movement of piston in the reciprocate engine.To avoid effect by tar,the system is comprised the rotary engine coupled to a generator since there is no piston inside the engine.As for gasification system,downdraft gasifier is designed and installed.In this study woody biomass was gasified.The gasifier performance was evaluated with respect to fuel consumption rate.The rotary engine-generator system was evaluated in terms of power generation efficiency.Result of this study shows that fuel consumption rate was about 30 kg/h,gasification efficiency was about 63.4%and efficiency of rotary engine system was about 9.4%.

Si-C Foam Porous-Medium Combustion Power-Generation System for Low-Calorific-Value Biomass Syngas

Syngas produced from the gasification of organic feedstocks from biomass is one of the clean and sustainable sources of energy.The advantages of simple access and renewability of biomass energy can meet the energy needs of temporary power supply.This study presents a biomass power-generation system for vehicular applications.Using biomass and a free-piston Stirling engine generator(FPSEG)as the primary material and prime mover,respectively,biomass energy is converted into electricity by combusting the syngas to heat the FPSEG.Matching and key parameter design for biomass gasification and thermoelectric conversion systems within a power generation system were performed.A porous medium area was constructed using Si-C foam ceramics to obtain an energy-conversion experimental platform.The effects of bed height,porosity,porous-region diameter,and air-intake conditions on the power-generation performance were investigated,and optimisations were performed for the thermoelectric conversion system.The rate of increase during FPSEG power generation first increased and then decreased with increasing bed height,peaking at a bed height of 40 mm.An increasing porous-region diameter accelerated FPSEG power generation,whereas porosity changes in the porous media did not significantly affect the rate of change during FPSEG power generation.With increasing air intake,the rate of increase during power generation first increased and then decreased.The maximum change rate and the highest thermoelectric conversion efficiency of the power-generation system occurred at 9.5 m^(3)/h and 6.5 m^(3)/h(~45.1%)air intakes,respectively.Optimising the thermal inertia and combustion structure of the thermoelectric conversion system significantly increased the power-generation rate of the system,with 1.8 W/s being observed at a 9.7 m^(3)/h air intake.

Current status of national integrated gasification fuel cell projects in China

Coal has been the main energy source in China for a long period.Therefore,the energy industry must improve coal power generation efficiency and achieve near-zero CO_(2) emissions.Integrated gasification fuel cell(IGFC)systems that combine coal gasification and high-temperature fuel cells,such as solid oxide fuel cells or molten carbonate fuel cells(MCFCs),are proving to be promising for efficient and clean power generation,compared with traditional coal-fired power plants.In 2017,with the support of National Key R&D Program of China,a consortium led by the China Energy Group and including 12 institutions was formed to develop the advanced IGFC technology with near-zero CO_(2) emissions.The objectives of this project include understanding the performance of an IGFC power generation system under different operating conditions,designing master system principles for engineering optimization,developing key technologies and intellectual property portfolios,setting up supply chains for key materials and equipment,and operating the first megawatt IGFC demonstration system with near-zero CO_(2) emission,in early 2022.In this paper,the main developments and projections pertaining to the IGFC project are highlighted.

Numerical Calculation of a 3000MWt MHD-steam Combined Cycel System with Tail Gasification

A numerical calculation of a 3000MWt MHD steam combined cycle system with tail gasification is described . The research scheme has been set up and the parameters of this system have been designed. Then the efficiency of the combined cycle system has been calculated which is up to 53.9%.

Industrialization prospects for hydrogen production by coal gasification in supercritical water and novel thermodynamic cycle power generation system with no pollution emission

Energy conversion and utilization, particularly carbon-based fuel burning in air phase, have caused great environmental pollution and serious problems to society. The reactions in water phase may have the potential to realize clean and efficient energy conversion and utilization. Coal gasification in supercritical water is a typical carbon-based fuel conversion process in water phase, and it takes the advantages of the unique chemical and physical properties of supercritical water to convert organic matter in coal to H2 and CO2. N, S, P, Hg and other elements are deposited as inorganic salts to avoid pollution emission. The State Key Laboratory of Multiphase Flow in Power Engineering has obtained extensive experimental and theoretical results based on coal gasification in supercritical water. Supercritical water fluidized bed reactor was developed for coal gasification and seven kinds of typical feedstock were selected. The hydrogen yield covers from 0.67 to 1.74 Nm3/kg and the carbon gasification efficiency is no less than 97%. This technology has a bright future in industrialization not only in electricity generation but also in hydrogen production and high value-added chemicals. Given the gas yield obtained in laboratory-scale unit, the hydrogen production cost is U.S.$ 0.111 Nm3 when the throughput capacity is 2000 t/d. A novel thermodynamic cycle power generation system based on coal gasification in supercritical water was proposed with the obvious advantages of high coal-electricity conversion efficiency and zero pollutant emission. The cost of U.S.$ 3.69 billion for desulfuration, denitration and dust removal in China in 2013 would have been saved with this technology. Five kinds of heat supply methods are analyzed and the rates of return of investment are roughly estimated. An integrated cooperative innovation center called a new type of high-efficient coal gasification technology and its large-scale utilization was founded to enhance the industrialization of the technology vigorously.

Alkali-thermal gasification and hydrogen generation potential of biomass

Generating hydrogen gas from biomass is one approach to lowering dependencies on fossil fuels for energy and chemical feedstock, as well as reducing greenhouse gas emissions. Using both equilibrium simulations and batch experiments with NaOH as a model alkaline, this study established the technical feasibility of converting various biomasses （e.g., glucose, cellulose, xylan and lignin） into H2-rich gas via catalyst-free, alkali-thermal gasification at moderate temperatures （as low as 300℃）. This process could produce more H2 with less carbon-containing gases in the product than other comparable methods. It was shown that alkali-thermal gasification follows CxHyO2 ＋ 2xNaOH ＋ （x-z）H20 = （2x＋y/2-z）H2 ＋xNa2CO3, with carbonate being the solid product which is different from the one suggested in the literature. Moreover, the concept of hydrogen genera- tion potential （H2-GP）-the maximum amount of H2 that a biomass can yield, was introduced. For a given biomass CxHyO2, the H2-GP would be （2x ＋ y/2-z） moles of H2. It was demonstrated experimentally that the H2-GP was achievable by adjusting the amounts of H20 and NaOH, temperature and pressure. Keywords hydrogen generation potential, biomass, lignocellulose, alkali-thermal gasification, sodium hydroxide

A New Cleaner Power Generation System Based on Self-Sustaining Supercritical Water Gasification of Coal

A new cleaner power generation system(IPGS) is proposed and investigated in this paper. Integrating combined cycle with supercritical water gasification of coal, the thermodynamic energy of the produced syngas is cascade utilized according to its temperature and pressure, both sensible and latent heat of the syngas can be recycled into the system, and thereby the net power efficiency can be about 6.4 percentage points higher than that of the traditional GE gasification based power plant(GEPP). The exergy analysis results show that the exergy efficiency of the proposed system reaches 52.45%, which is 13.94% higher than that of the GEPP, and the improvement in exergy efficiency of the proposed system mainly comes from the exergy destruction decline in the syngas energy recovery process, the condensation process and the syngas purification process. The syngas combustion process is the highest exergy destruction process with a value of 157.84 MW in the proposed system. Further performance improvement of the proposed system lies in the utilization process of syngas. Furthermore, system operation parameters have been examined on the coal mass fraction in the supercritical water gasifier(GF), the gasification temperature, and the gasification pressure. The parametric analysis shows that changes in coal concentration in the GF exert more influence on the exergy efficiency of the system compared with the other two parameters.

Biomass energy cost and feasibility of gasifier based biomass power generation system

The present research work has been carried out on biomass based on 10 kW capacity gasifier power generation system installed at College of Agricultural Engineering and Technology,Dr.Panjabrao Deshmukh Agricultural University(Dr.PDKV),Akola Maharashtra,India.The main objectives were to evaluate various costs and benefits involved in the power generation system.The costs of energy per unit were calculated for the first year of operation.The economics of gasifier based power generation system and thereby the feasibility of the system was examined by estimating per unit cost,Net Present Value(NPV),Benefit Cost Ratio(BCR),Internal Rate of Return(IRR)and payback period.The discount cash flow method was used to find out the IRR.In the present analysis,three costs viz.,installed capital cost,operation and maintenance cost,and levelised replacement cost were examined for the evaluation of the power generation per unit.Discount rate on investment in case of subsidy(Case I)and in case without subsidy(Case II)for installation cost of system was considered as 12.75%.The BCR comes in Case I for operating duration of 22 h,20 h,and 16 h are 1.24,1.18,and 1.13,respectively.Similarly for Case II BCR comes 1.44,1.38,and 2.39.The IRR comes in Case I for operating duration of 22 h,20 h,and 16 h are 26%,22%,and 19%,respectively.Similarly for Case II,IRR comes 52%,44%,and 39%for operating duration of 22 h,20 h,and 16 h,respectively.The payback period in the present analysis was worked out.The payback period for biomass based gasifier power generation system was observed to be for Case I from three to four years and for Case II it was one to two years.

Integrated benefits of power generation by straw biomass--A case study on the Sheyang Straw Power Plants in Jiangsu Province,China

Power generation using straw biomass has quantifiable benefits from an economic,ecological,and sociological perspective in China.The methods used to construct the assessment models of these integrated benefits were the revenue capitalization approach and the discounted-cash-flow approach.The results indicated that a straw power plant with the capacity of 2.50×10^(7)W and burning 1.23×10^(5)tons of cotton straw could annually supply 1.40×10^(8)kWh of power.However,it would not be until six years later that these results could be measured.Over the long term,the gross benefits could reach up to 4.63×10^(8)Yuan.Therefore,the total benefits are expected to be 1.18×10^(12)Yuan if all available straw resources are used to generate power.The policy implication showed that the long-term integrated benefits of power generation by straw biomass outweighed the short-term benefits.This is the main incentive to use straw biomass for power generation in the future.

Renewable Energy:Wind Turbines,Solar Cells,Small Hydroelectric Plants,Biomass,and Geothermal Sources of Energy

In this paper,we present five basic types of renewable energy sources,namely:wind turbines,solar cells,small hydroelectric plants,biomass,and geothermal sources of energy.Wind turbines transform energy of wind into electrical energy,solar cells transform energy of sun into electric energy,hydroelectric plants transform energy of water into electric energy,devices or machines can be constructed to transform energy of biomass into heat energy,and geothermal energy into some form of energy.In this paper we present basic information and reasons why there is need today to use these forms of energy—called green energies,we present how these devices or machines function,and we propose for future work design of typical devices or machines that will satisfy basic functional needs.

电力市场环境下生物质气化耦合燃煤机组与风电场联合自调度优化策略

利用生物质气化耦合燃煤发电技术可以提升火电机组的燃料及运行灵活性,从而促进风电的高水平消纳,同时实现生物质能的有效开发利用。该文首先建立反映生物质气化耦合热电联产机组内部能流过程和外部出力特性的运行模型。然后,从能源供应商视角出发,给出耦合机组与风电场联合参与日前、日内和实时平衡市场的多阶段决策框架,提出反映联合体期望收益和条件风险价值的多目标自调度策略。最后,利用基于字典优化框架的增强ε约束法,给出构建帕累托前沿的多目标优化求解流程。以一台350 MW燃煤热电联产机组和一座600 MW风电场构成的联合体为例进行分析。结果可知,增设生物质气化子系统和联合运行能够使其经济效益提升6%左右,同时有利于降低能源供应商的运营风险。

An overview of biofuel power generation on policies and finance environment,applied biofuels,device and performance

The prices of fossil fuels,the gap between energy supply and demand,energy security,environmental issues,and the reduction of greenhouse gas emissions commonly promote the development of biomass power generation in China.Compared to direct biomass combustion power generation and biogas power generation,liquid biofuel power generation has better application potential.Policies and finance environment of countries and organizations have promoted the extensive application of biofuel power generation in recent years,especially in China.Evaluation of internal combustion engine,gas turbine and fuel cell on the stationary power station and mobile generation shows that gas turbine is the main generator-set,the fuel cell is the fastest-growing and future generator-set,while the engine is the first choice in transport and low power generation field.As the second,third and fourth generation biofuels,biomethanol,bioethanol,biodiesel and others have been researched and widely used in power generation.In addition,power generation performance and emissions have been improved to some extent after biofuels supplying.For the future,combined heat and power(CHP)generation and integrated gasification combined cycle(IGCC)is imperative development trends of power generation for higher energy and exergy efficiency.CHP based on the various generating facilities will be the next choice and direction of energy use trends for transport.

考虑多重不确定性的电-热-气综合能源系统协同优化方法

综合能源系统(IES)中风-光出力和负荷不确定性对系统的运行安全和规划提出了挑战。以包含光伏、生物质气化热电联产等设备的IES调度过程为例,提出一种集成随机规划-信息间隙决策理论(IGDT)的方法应对系统优化运行过程中源-荷侧的多重不确定性。随机规划方法处理光伏出力不确定性,并将优化结果作为IGDT处理负荷不确定性的基准值。其中,IGDT中的风险规避和风险寻求策略反映了系统管理者面对不确定性带来运行风险时的态度。结果表明,风险规避策略下生物质气化热电联产日电能输出总量高于风险寻求策略下生物质气化热电联产日电能输出总量的50%。不同策略下的调度结果差异性为系统管理者提供了灵活的选择。

生物质气化发电项目经济性分析

对2MW和6MW生物质气化发电站项目的经济性进行了分析和比较。在目前的经济环境下,生物质气化发电的设备成本为5000～6500$/kW,上网电价在0.60～0.65$/kWh的条件下,项目投资回收期在6～8a之间。6MW规模电站的投资成本虽然比2MW的高,但采用了更先进的技术,系统效率提高、技术经济性较优。生物质单价和税率是影响生物质气化发电经济性的两个重要因素,发电成本、投资回收期和内部收益率等对这些因素非常敏感。生物质单价或税率提高,都会导致项目经济性降低,表现为发电成本增加、投资回收期增长和内部收益率下降。

串行流化床生物质气化制取合成气试验研究

串行流化床气化是一种崭新的气化技术,可将气化和燃烧过程分隔开,气化反应器和燃烧反应器之间依靠惰性固体载热体进行热量传递。以水蒸气为气化介质,在小型串行流化床试验装置上进行生物质气化制取合成气的试验研究,探讨气化反应器温度T、水蒸气与生物质比率S/B对气化结果的影响。试验结果表明,燃烧反应器内燃烧烟气不会串混至气化反应器,该气化技术能够稳定连续地从气化反应器获得不含N2的高品质合成气。随着气化反应器温度的提高,合成气中?(H2)/?(CO)减小,合成气产率增加,热值降低,总碳转换率先升高而后保持不变。随着S/B的增大,合成气产率和总碳转换率均先升高而后降低,S/B的最佳值为1.4。在试验阶段获得的最高合成气产率为1.87m3/kg,合成气热值为13.20MJ/m3,总碳转化率为91%。