串行流化床生物质气化制氢试验研究

基于串行流化床生物质气化技术,以水蒸气为气化剂,在串行流化床试验装置上进行生物质气化制氢的试验研究,考察了气化反应器温度、水蒸气/生物质比率(S/B)对气化气成分、烟气成分和氢产率的影响。结果表明:在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N_2的富氢燃气,氢浓度最高可达71.5%;气化反应器温度是影响制氢过程的重要因素,随着温度的升高,气化气中H_2浓度不断降低,CO浓度显著上升,氢产率有所提高;S/B对气化气成分影响较小,随着S/B的增加,氢产率先升高而后降低,S/B的最优值为1.4。最高氢产率(60.3g H_2/kg biomass)是在气化反应器温度为920℃,S/B为1.4的条件下获得的。     

纤维素废弃物稀酸水解残渣制氢研究

对纤维素废弃物水解残渣催化气化制氢进行了研究,考察了气化温度、催化温度、催化剂颗粒粒径和S/B (单位时间内进入气化器中水蒸汽质量与生物质质量之比)4个主要参数对气体组成和氢气产率的影响并和以木屑为原料催化气化制氢进行了比较。在试验范围内提高气化温度、催化温度和S/B的值以及减小催化剂颗粒粒径对提高氢产率有利,其中气化温度和S/B对提高氢产率影响较大。气化温度在800～850℃内较为理想,催化剂颗粒的适宜粒径为2～3mm,S/B取1.5～2.0较佳;和木屑制氢相比,使用水解残渣制取的气体中CO和CO_2的体积百分比小,H_2/CO的值大,氢气含量高,有利于后续处理,且氢产率大,对制氢有利。     

稻壳与木屑气化制取富氢燃气的试验研究

采用单一流化床二步气化方法,以纯水蒸气为气化剂,在流化床中进行制取氢气的工艺试验。在对试验数据进行分析的基础上,探讨了一些主要参数[如反应器温度、水蒸气/生物质(S/B)、生物质化学成分]对氢产率的影响。分析结果表明:较高的反应温度、S/B以及纤维素和半纤维素含量比较有利于氢的产出。验证试验表明:在反应温度为1000~1050℃,S/B为2.0的条件下,纤维素和半纤维素含量为74.1%的木屑(干基)的氢产率最高,为61.67g/kg。     

生物质流化床气化制取富氢燃气的研究

以流化床为反应器，对生物质空气-水蒸汽气化制取富氢燃气的特性进行了一系列实验研究。在本实验中，气化介质(空气)从流化床底部进人反应器，水蒸汽从进料点上方通人反应器。在对实验数据进行分析的基础上，探讨了一些主要参数如：反应器温度，水蒸汽／生物质比率S／B(Steam／Biomass Ratio)，当量比ER(Equivalence Ratio)以及生物质粒度对气体成分和氢产率的影响。结果表明：较高的反应器温度，适当的ER和S／B(在本实验研究中分别为0．23，2．02)，以及较小的生物质颗粒比较有利于氢的产出。最高的氢产率：71gH2／kgbiomass是在反应器温度为900℃，ER为0．22，S／B为2．70的条件下取得的。     

生物质富氧——水蒸气气化制氢特性研究

以一个鼓泡流化床为反应器,对生物质富氧—水蒸气气化制取富氢燃气的特性进行了一系列的实验研究。通过对试验数据的分析,探讨了主要参数温度、水蒸气/生物质(S/B)和氧浓度对气体成分、氢产率和潜在产氢量的影响。结果表明:在3个主要参数的变化范围内,氢产率和潜在氢产量受温度的影响最大:当温度从700~900℃时,每千克生物质氢产量从18g增加到了53g,每千克生物质潜在氢产量从71.6g增加到了115.6g。     

双流化床生物质气化及CO2捕获的模拟

用Aspen Plus建立了双流化床气化和燃烧模型,对生物质在双流化床中气化及CaO吸收合成气中的CO2过程进行了模拟研究;探讨不同反应条件:气化温度、蒸汽与生物质的质量配比(S/B)以及CaO循环量与生物质的质量配比(Ca/B)对合成气成分的影响,为该类型工业反应器的研发提供了理论依据.模拟分析结果表明:气化温度低于700℃时,CaO能很好地吸收气化过程中产生的CO2并促进平衡反应向产氢方向进行;在温度为650℃及CaO作用下,S/B在0.6～1.7内对合成气成分的影响不大;CaO的加入能够有效地改善合成气的组成,合成气中氢气浓度能达到95％以上,氢气产量达到52 mol/kg.     

生物质气化制氢的模拟

以秸秆为研究对象,利用Aspen P lus软件建立气化反应器模型,对生物质气化制氢进行模拟计算.探讨不同反应条件,包括气化温度、生物质与蒸汽质量配比以及催化剂对富氢气体成分的影响.计算结果表明,未加催化剂条件下,采用生物质蒸汽气化技术可获得体积分数为6000/以上的富氢燃料气,增大蒸汽与生物质质量配比有利于氢气产率的提高;添加CaO、MgO催化剂可较大幅度地提高氢气产率,氢气体积分数最大可达到9400/,其中CaO对生物质气化制氢过程的催化作用非常显著.     

基于铁矿石载氧体25 kWth串行流化床生物质化学链气化实验研究

设计并建立了25kW_(th)串行流化床生物质气化反应器,基于此反应器,以赤铁矿石作为载氧体,开展生物质化学链气化实验研究,考察气化反应器温度、S/B、载氧体添加比例对生物质气化特性的影响。当赤铁矿占床料比例高于40%时,该气化装置的气化反应器温度保持平稳,铁矿石载氧体的再生及传热性能优良。燃料反应器出口烟气的成分为H_2、CO_2、CO、CH_4和少量的C_2H_4。随着气化反应器温度升高,气化反应器出口烟气中CO、CH_4和C_2H_4体积分数逐渐降低,相应的CO_2体积分数逐渐升高。随着S/B由0.6升高到1.4,气化反应器出口烟气中H_2和CO_2体积分数逐渐升高,CO、CH_4和C_2H_4体积分数逐渐降低。另外,载氧体添加比例增加,生物质气化反应器出口烟气中CO、H_2、CH_4和C_2H_4体积分数呈减小的趋势,而CO_2体积分数显著增加。     

生物质在超临界水流化床反应系统中气化制氢实验研究

以生物质模型化合物葡萄糖为原料,在温度500～600℃,压力23～37胁范围内,利用新研制的超临界水流化床系统对其气化制氧特性进行研究,讨论了过程主要参数温度、压力、物料浓度以及催化剂添加对气化制氢的影响.实验结果表明:温度对气化影响最大,而压力对气化的影响较小,升高温度和压力都有利于产氢.随着物料浓度增加葡萄糖气化效果下降,在超临界水流化床气化制氢系统中实现30%葡萄糖的连续稳定气化.K_2CO_3提高气化率同时降低了产气中CO含量,ZnCl_2的加入虽对气化率影响不大,但大大提高了氢气的选择性.该文的实验研究验证了超临界水流化床气化制氢系统的有效性.     

生物质气化费托合成航空煤油的模拟和火用分析

基于Aspen Plus软件对生物质串行流化床气化费托(FT)合成加氢裂化制取航空煤油进行模拟和热力学分析,研究操作参数变化和副产品蜡循环利用对系统性能的影响。结果表明:系统损失主要在气化子系统中,而合成气提质子系统损较小,过程不可逆损是系统损的主要来源,内部损率为88.3%,生物质大分子结构改变是造成不可逆损的主要原因。所有操作参数中水蒸气与生物质质量配比(S/B)对系统效率影响最大,气化合成气H_2与CO物质的量之比(H_2/CO)在1.95～2.00为宜,增大合成温度和压力可提高系统航空煤油产率和效率。对于玉米秆气化FT加氢裂化制取航空煤油系统,推荐的操作参数:气化温度和压力750℃,0.1～0.2 MPa,S/B为0.4～0.5,合成温度240℃,合成压力1.5～2.0 MPa。此时,航空煤油产率最大可达85.3 kg/t,系统效率为54.3%。副产品蜡进行循环利用,可提高航空煤油产率3.9%,并降低最佳S/B为0.3～0.4。     

Fundamental design of a continuous biomass gasification process using a supercritical water fluidized bed

A novel biomass gasification (first stage of hydrogen production from biomass) process using a supercritical water fluidized bed was proposed and the fundamental design of the process was conducted. The flow rate was determined by evaluating the minimum fluidization velocity and terminal velocity of alumina particles enabling fluidization with the thermodynamic properties of supercritical water. Three cases were examined: a bubbling fluidized bed in which water was used mainly as the fluidized medium and biomass were added for gasification, a bubbling fluidized bed fluidized by biomass slurry feed alone, and a fast fluidized bed fluidized by biomass slurry feed alone. According to calculations of the residence time and thermal efficiency assuming heat recovery with a heat exchanger efficiency of 0.75, the bubbling fluidized bed fluidized by biomass slurry alone was appropriate for continuous biomass gasification using a fluidized bed.     

生物质富氧气化气作为机动车燃料的初步试验

试验研究了生物质气化产出气作为机动车燃料的可行性.在实际运行的生物质气化系统中进行了富氧试验,并将生物质富氧气化产出气作为机动车燃料,进行了行驶试验.分析了富氧气化剂对于气化产出气成分的影响,对生物质气化产出气作为机动车燃料的经济可行性进行了简单分析.结果表明,采用富氧气化剂可以明显提高产出气的热值,增加气体的能量密度,同时,产出气作为燃料能够满足机动车的动力性要求;在生物质原料成本控制在一定范围内的情况下,生物质气化产出气作为汽车燃料能够体现一定的经济性.     

4MW级生物质气化发电示范工程的设计研究

介绍了我国4MW级的生物质气化整体联合循环发电示范工程的设计特点。该工艺中使用了中温静电除尘、焦油裂解装置和显热回收系统，预计投运后，将会使生物质的气化效率提高、可燃气中焦油含量减少以及系统效率得以提高，为我国生物质能的开发与运用开辟了广阔的前景。     

户用型下吸式生物质气化炉性能研究

由于生物质能具有储量大、环境友好等特点,生物质气化技术尤其是户用型气化技术在我国农村应用值得研究。论文在建立下吸式户用型气化系统上,研究了不同生物质原料的气化性能,如对温度分布、气化效率、燃气热值、燃气产量等,并进行了焦油脱除效率的研究。结果表明,该炉型的气化效率可达70％,燃气热值达到6MJ／m3,燃气中焦油含量降低至20mg／m3。     

生物质焦油防水膏试验研究

从生物质焦油资源的综合利用和环境保护的角度出发，提出用生物质焦油作主要原料研究开发新型的高效防水膏，通过对生物质焦油防水膏样品的吸水性和耐热性能的试验研究，表明防水膏中的生物质焦油含量越高其防水性能越好，而耐热性能越差。当防水膏中的生物质焦油含量为45％，时其综合性能最佳，既易于施工，又有较好的防水作用，具有显著的经济和环境效益，适用于工业和民用建筑的防水材料。     

Exergy analysis of biomass-to-synthetic natural gas (SNG) process via indirect gasification of various biomass feedstock

This paper presents an exergy analysis of SNG production via indirect gasification of various biomass feedstock, including virgin (woody) biomass as well as waste biomass (municipal solid waste and sludge). In indirect gasification heat needed for endothermic gasification reactions is produced by burning char in a separate combustion section of the gasifier and subsequently the heat is transferred to the gasification section. The advantages of indirect gasification are no syngas dilution with nitrogen and no external heat source required. The production process involves several process units, including biomass gasification, syngas cooler, cleaning and compression, methanation reactors and SNG conditioning. The process is simulated with a computer model using the flow-sheeting program Aspen Plus. The exergy analysis is performed for various operating conditions such as gasifier pressure, methanation pressure and temperature. The largest internal exergy losses occur in the gasifier followed by methanation and SNG conditioning. It is shown that exergetic efficiency of biomass-to-SNG process for woody biomass is higher than that for waste biomass. The exergetic efficiency for all biomass feedstock increases with gasification pressure, whereas the effects of methanation pressure and temperature are opposite for treated wood and waste biomass.     

基于热化学平衡机理的生物质气化过程模型

生物质气化是生物质能利用的有效方式之一,通过分析气化过程热化学反应机理,基于气化过程的物料平衡、热量平衡和热化学反应平衡关系,建立了一种生物质气化过程的热化学平衡模型.由该模型模拟计算了锯屑、棉花秸和木粉三种生物质料在以空气为气化剂,不同输入参数(物料湿度和气化剂当量比)下的气化气组分及气体产率,考察了当模型输入参数分别变化时气化气组分、气体产率的变化情况,结果表明该模型输出值与文献值的变化趋势基本相符,模拟具有较好的预测效果.     

Solar thermochemical gasification of wood biomass for syngas production in a high-temperature continuously-fed tubular reactor

Biomass gasification is an attractive process to produce high-value syngas. Utilization of concentrated solar energy as the heat source for driving reactions increases the energy conversion efficiency, saves biomass resource, and eliminates the needs for gas cleaning and separation. A high-temperature tubular solar reactor combining drop tube and packed bed concepts was used for continuous solar-driven gasification of biomass. This 1 kW reactor was experimentally tested with biomass feeding under real solar irradiation conditions at the focus of a 2 m-diameter parabolic solar concentrator. Experiments were conducted at temperatures ranging from 1000 °C to 1400 °C using wood composed of a mix of pine and spruce (bark included) as biomass feedstock. This biomass was used under its non-altered pristine form but also dried or torrefied. The aim of this study was to demonstrate the feasibility of syngas production in this reactor concept and to prove the reliability of continuous biomass gasification processing using solar energy. The study first consisted of a parametric study of the gasification conditions to obtain an optimal gas yield. The influence of temperature, oxidizing agent (H₂O or CO₂) or type of biomass feedstock on the product gas composition was investigated. The study then focused on solar gasification during continuous biomass particle injection for demonstrating the feasibility of a continuous process. Regarding the energy conversion efficiency of the lab scale reactor, energy upgrade factor of 1.21 and solar-to-fuel thermochemical efficiency up to 28% were achieved using wood heated up to 1400 °C.     

Systems analysis of integrating biomass gasification with pulp and paper production - Effects on economic performance, CO2 emissions and energy use

This paper evaluates system aspects of biorefineries based on biomass gasification integrated with pulp and paper production. As a case the Billerud Karlsborg mill is used. Two biomass gasification concepts are considered: BIGDME (biomass integrated gasification dimethyl ether production) and BIGCC (biomass integrated gasification combined cycle). The systems analysis is made with respect to economic performance, global CO₂ emissions and primary energy use. As reference cases, BIGDME and BIGCC integrated with district heating are considered. Biomass gasification is shown to be potentially profitable for the mill. The results are highly dependent on assumed energy market parameters, particularly policy support. With strong policies promoting biofuels or renewable electricity, the calculated opportunity to invest in a gasification-based biorefinery exceeds investment cost estimates from the literature. When integrated with district heating the BIGDME case performs better than the BIGCC case, which shows high sensitivity to heat price and annual operating time. The BIGCC cases show potential to contribute to decreased global CO₂ emissions and energy use, which the BIGDME cases do not, mainly due to high biomass demand. As biomass is a limited resource, increased biomass use due to investments in gasification plants will lead to increased use of fossil fuels elsewhere in the system.     

An innovative biomass gasification process and its coupling with microturbine and fuel cell systems

The use of biomass, wood in particular, is one of the oldest forms of producing energy for heating or cooking. Nowadays, new technologies concerning the utilisation of biomass or waste residues are in demand and the trend to use them in decentralised applications for combined heat and power (CHP) production provides an attractive challenge to develop them. At the TU München an innovative allothermal gasification technology, the Biomass Heatpipe Reformer (BioHPR) has been developed. The aim of this project was to integrate the technology of liquid metal heatpipes in the gasification process in order to produce a hydrogen rich product gas from biomass or residues. The gasification product can be further used in microturbine or SOFC systems. The present paper presents the aforementioned gasification technology, its coupling with innovative CHP systems (with microturbine or fuel cells) and investigates, through the simulation of these systems, the optimum conditions of the integrated systems in order to reach the highest possible efficiencies.