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1、生物质气化发电机组中内燃机的运行特性分析任永志1，崔亨哲1，郭军1，李维尧2辽宁省能源研究所 辽宁 营口 115000；辽宁省宽甸县农村能源办公室，辽宁 宽甸 118200摘要：本文针对生物质气化机发电系统中的燃气发电机组的实验测试结果分析了其运行特性，结果表明，低热值生物质气化产出气能够满足内燃式燃气发电机的运行要求，只是在能够实现的最大输出功率方面受到限制；生物质气化机发电系统的尾气排放能够满足环保的要求；内燃式发电机与生物质气化机组间具有良好的匹配性。关键词：生物质；气化；内燃机 The Performance and Analysis of SI Engine in Biomass G
2、asification for Power SystemRen Yong-zhi1, Cui Heng-zhe1, Guo Jun1, Li Wei-yao2(1. Liaoning Institute of Energy Resources, Yingkou 115000, China; 2. Kuandian Office of Rural Energy, Kuandian 118200, China)Abstract:Experiments have been carried out with a Tessari 80kW SI engine in conjunction with a
3、fixed bed biomass gasification unit, the results of analysis on the experiment data shows that the lower caloric value producer gas can satisfy the requirement of the SI engine for power generation except for the limit of the maximum power output; the exhausted gases of the SI engine can reach the r
4、equirement for environment protection; the SI engine matches well with the biomass gasification unit. Key words: biomass; gasification; SI engine1. 前言生物质气化发电技术作为生物质能源化利用的一项有效途径在国内外得到广泛的研究和不同程度的应用，辽宁省能源研究所在国家“十五”科技攻关计划项目“50kW生物质气化发电机组研制”的执行过程中，在所建设的生物质气化发电系统示范点针对生物质气化机组和燃气发电机组分别进行了实验测试，本文根据燃气发电机组的测试结
5、果对其运行特性进行了分析，以验证内燃式发电机与生物质气化机组间的可匹配性并评估以生物质气化产出气为燃料时，燃气发电机尾气对于环境的影响。2. 系统组成和技术指标如图一，生物质气化发电系统由螺旋输送机、下吸式气化炉、旋风除尘器等净化设备、罗茨鼓风机、安全水封、专用灶具、内燃式发电机、湿法储气柜以及地下管网等组成，系统在保证居民生活用气的同时，将富裕的产出气用于发电，实现气电联产。1.螺旋输送机 2.下吸式气化炉 3.旋风除尘器 4.喷淋净化器 5.气水分离器 6.生物质过滤器 7.罗茨鼓风机 8.安全水封 9.专用灶具 10.内燃式发电机 11.湿法储气柜图1 系统工艺流程图生物质气化机组原料处
6、理量为150190kg/h,产气量300380Nm3/h,气化效率7275%，产出气中焦油和灰含量17mg/Nm3，通过采用不同生物质物料并控制反应条件得到几种不同气体组分的产出气用于燃气发电机组的实验测试，同种原料在相同工况下得到的产出气进入储气柜后充分扩散混合，保证了燃气发电机入口可燃气体成分的一致性。3. 燃气发电机的测试方案3.1 燃气发电机规格测试实验采用意大利Tessari 80kW燃气发电机,采用六缸直列式IVECO 8210型内燃机，火花塞点火，汽缸直径和冲程为137156mm,总排气量为13.8L，转数为1500RPM。3.2 燃气发电机组测试方案 针对不同原料、不同工况的产
7、出气，测试燃气发电机入口气体组分焦油含量，燃气发电机组的输出功率在10kW、20kW、30kW、40kW、50kW、60kW、70kW、80kW工况下的气体耗耗量，从而计算不同负荷下燃气发电机的比气耗、效率并绘制特性曲线，考察气体组分对于燃气发电机功率特性的影响； 针对不同气体组分的产出气，测试燃气发电机组的输出功率在10kW、20kW、30kW、40kW、50kW、60kW、70kW、80kW工况下的尾气中NOx、CO2、CO等成分； 考察产出气中氢气组分的含量对于燃气发电机的影响； 在不同时间间隔，考察燃气发电机气体入口过滤器清洁情况和火花塞积炭情况； 选择最佳工况和最差工况，测试燃气发电
8、机的最长连续稳定运行时间；3.3 燃气发电机组测点布置及说明在燃气发电机入口布置温度、压力和流量测点，测量可燃气体的温度T1、压力P和流量F1、F2以及发电机入口可燃气的成分G2（VARIAN GC3800 气相色谱仪）和焦油含量（GB12208-90）；在燃气发电机尾气出口布置取样探头以测试燃气发电机尾气中一氧化碳等组分G1（意大利Tecnotest MULTIGAS 488型尾气测试仪）的含量，同时，通过相应的传感器测试发电机的转数和机油温度，除此之外，连接于两个分别为50kW和30kW的负载箱的测功仪将测试燃气发电机的实际输出功率。图2 燃气发电机组测点布置示意图4. 测试结果及分析 4
9、.1 气体组分分析和计算结果表1气体组分分析和计算结果气样编号12345产出气气体成分（%）CO215.3616.3617.0915.8713.92C2H4+C2H20.380.410.330.300.45C2H60.000.000.000.000.00H210.4210.6212.1512.9413.42O21.540.790.48待添加的隐藏文字内容30.450.00N256.0054.7052.6151.1149.27CH41.381.441.431.251.57CO14.9215.6815.9018.0821.38产出气热值Qdw（KJ/Nm3）3752.539134051.14323
10、.85 5002.8在燃气发电机入口测得的产出气中焦油含量与生物质气化机组出口基本一致，均小于17mg/Nm3；由于以空气为气化剂，产出气中含有大量N2，产出气被稀释，属于低热值燃气，表格中N2含量普遍比生物质气化机组所取气样中N2含量高，可以确定供气管路存在微小漏气点，由于燃气发电机运行的抽气作用而吸入少量空气，造成所取气样N2含量高，热值偏低于实际值。4.2 燃气发电机的功率特性分析燃气发电机启动容易，发电准备时间短，运行平稳，转速基本稳定在1500RPM，发电频率稳定在50Hz，由于燃气发电机的供气管存在轻微泄露，本次测试燃气发电机所实现的最高输出功率为72kW，没有达到其铭牌功率。采用
11、不同组分产出气所得到的比气耗和发电机效率曲线如图3所示。图3 比气耗与效率随着燃气发电机发电功率的增加，发电比气耗逐渐减小，根据不同产出气热值，在中高负荷下，一般为2.53Nm3/kW，同时效率逐渐提高，在低负荷情况下，其效率较低，由此看来，根据用户负荷情况选择容量适合的燃气发电机是必要的，虽然燃气发电机前测出的产出气组分不同且热值相差较大，但从燃气热值为3752.5kJ/Nm3到5002.8kJ/Nm3，发电机均能够平稳运行，同样发电负荷下燃气发电机的效率相差不多，均能达到30%，但是在所能实现的最高输出功率方面，低热值气体在发电机负荷到一定数量时不能维持内燃机的正常运转，出现发电机转数和发
12、电频率变化大并最终在不能满足符合情况下停机的现象。4.3 燃气发电机尾气排放分析从实际运行的效果看，燃气发电机尾气烟度很低，表明可燃气体与空气的混合充分，这是由于以分子状态存在的气体，相对于燃油（尽管也经过雾化）扩散性好，并且由于气体稀薄，可燃组分少，燃烧较完全，保证了燃气发电机的效率。表2发电机尾气成分测试结果输出功率(kW)尾气成分（%）CO(%)CO2(%)HC(ppm)O2(%)NOx(ppm)怠速0.3118.792.5234391.0590 0.2615.595.548141.16811 0.3313.897.619141.2620 0.1916.394.729391.13932
13、0.1917.494.139781.11241 0.1417.503.49481261.09652 0.131902.54532681.06363 0.1219.501.91583511.04668 0.111901.753741.04370 0.1819.900.633881.01272 0.1119.500.484001.008本身稀薄的产出气加上轻微空气被发电机吸入，因此表2显示排烟侧测得的空燃比（过量空气系数）均大于1，较高的空燃比有助于CO和HC（碳氢化合物）的燃尽，5个气样测出的尾气中CO和HC均含量很小，相对而言，CO和HC的含量在低负荷时较高，中高负荷时较低；表2中给出气样1和
14、气样5的NOx测试结果，可以看出，尾气中的NOx含量在低负荷时较低，中高负荷时较高，当燃气热值高时，NOx含量高，这是由于中高负荷时和燃气热值高时内燃机的燃烧温度高，促进了NOx的生成，文献4中指明，在空燃比稍大于1.0处，NOx的浓度将随负荷增加迅速增加，解释了气样5的NOx含量偏高的原因，因此，在保证燃气热值的条件下，适当提高空燃比，使混合气中燃料含量减少，成为稀薄燃烧，发动机的燃烧温度将降低，可以有效地控制NOx的生成，本次实验没有进行调节空燃比的尝试。国家火电厂大气污染物排放标准（GB13223 2003）中的规定NOx指标为：燃煤锅炉：4501100 mg/m3 (220537ppm
15、)燃油锅炉: 200 mg/m3 (98ppm)燃气轮机组: 80150 mg/m3 (3973ppm)通过调整空燃比，以生物质气化产出气为燃料的内燃机发电，应该能够达到燃油锅炉的尾气排放标准。4.4 焦油含量及氢气的含量对于燃气发电机的影响生物质气化气中的焦油和灰分含量过多会使火花塞积炭而不能打火，总计约110个小时实验结束后，拆下火花塞和发电机供气管入口的电磁阀观察，非常清洁，见图4和图5，表明焦油和灰份含量小于17mg/Nm3的产出气使火花塞积炭的可能性很小，能够满足发电机组的可靠运行。图4 火花塞积炭情况图5 燃气发电机气体入口过滤器由于产出气中H2的甲烷值最低，为0，实验前认为H2组
16、分增加时会出现内燃机汽缸内爆震的现象，从燃气发电机前气体取样分析的结果看，H2组分含量最多为13.42%，最少为10.42%，实验期间没有爆震现象，由于以空气为气化介质的生物质气化气中的N2的组分普遍在40%以上，加上CO2、CO（甲烷值为73）的存在，起到了惰性作用；文献2采用高达34% H2的生物质两步法气化产出气进行了内燃机发电实验，经过调整空燃比和压缩比，解决了爆震问题。图6 当量空气系数与产出气成分关系如图6所示，空气气化的最佳当量比在0.28左右，此条件下，产出气中H2的含量在20%左右，事实上，为了得到焦油含量较少的产出气，往往需要提高反应温度，因提高反应温度而提高当量比，当量比
17、提高的同时，产出气中H2的含量也就相应的减少了。由此看来，以空气为气化介质的生物质气化产出气能够满足燃气发电机的匹配要求。5. 结论上述分析表明，不同组分、不同热值的生物质气化产出气在一定范围内均可以作为内燃式燃气发电机燃料并保证可靠运行，但所能够实现的最大发电功率却不同；随着燃气发电机发电功率的增加，发电比气耗逐渐减小，在中高负荷下，一般为2.53Nm3/kW，在低负荷情况下，燃气发电机效率较低；燃用生物质气化产出气的发电机尾气中CO和HC均含量很小，通过合理调整空燃比，尾气中NOx含量应该能够达到燃油锅炉的尾气排放标准；焦油含量及氢气的含量对于燃气发电机的影响比预想小，这些均表明，生物质气
18、化机组与内燃式燃气发电机具有良好的匹配性，其集成系统是环境友好的生物质能源利用系统。参考文献：1 任永志，刘洪刚，崔亨哲等. 50kW固定床生物质气化热电联供系统的研究A. 21世纪太阳能新技术C. 上海：上海交通大学出版社，2003. 709-7122 Jesper Ahrenfeldt, Troels Pedersen, Jesper Schramm. FORD VSG 411 FUELED BY PRODUCER GAS FROM A TWO-STAGE GASIFIERA. Proceedings of 1st World Conference on Biomass for Energ
19、y and IndustryC. London, UK：James & James (Science Publishers) Ltd，20003 王明华. 内燃机节能手册M. 北京：化学工业出版社，19874 蒋德明. 内燃机原理M. 北京：中国农业机械出版社，19815 T.B. Reed. Biomass Gasification Principles and TechnologyM. New Jersey, USA: Noyes Data Corporation, 1981基金项目：国家“十五”科技攻关项目（2001BA403B0305）作者简介：任永志（1968-），男，副研究员，从事
20、生物质气化技术的研究和开发工作。Editors note: Judson Jones is a meteorologist, journalist and photographer. He has freelanced with CNN for four years, covering severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle around a shortwave radio
21、 and through the crackling static from space hear the faint beeps of the worlds first satellite - Sputnik. I also missed watching Neil Armstrong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fascinated with what goes on
22、 in the sky, and when NASA pulled the plug on the shuttle program I was heartbroken. Yet the privatized space race has renewed my childhood dreams to reach for the stars.As a meteorologist, Ive still seen many important weather and space events, but right now, if you were sitting next to me, youd he
23、ar my foot tapping rapidly under my desk. Im anxious for the next one: a space capsule hanging from a crane in the New Mexico desert.Its like the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unimaginable free fall from t
24、he edge of space - live.The (lack of) air up there Watch man jump from 96,000 feet Tuesday, I sat at work glued to the live stream of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they would just line up in a vert
25、ical straight line we would be go for launch.I feel this mission was created for me because I am also a journalist and a photographer, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do this, Felix Baumgartner, mu
26、st have that same feeling, at a level I will never reach. However, it did not stop me from feeling his pain when a gust of swirling wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon, with skin no thicker tha
27、n a dry cleaning bag, scraped the ground I knew it was over.How claustrophobia almost grounded supersonic skydiverWith each twist, you could see the wrinkles of disappointment on the face of the current record holder and capcom (capsule communications), Col. Joe Kittinger. He hung his head low in mi
28、ssion control as he told Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunday.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity
29、and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of co
30、mmercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, Fearless Felix will unclip. He
31、 will roll back the door.Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not
32、be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he appro
33、aches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-
34、meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wo
35、nt. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way Id miss this.
