压缩机论文模板范文

The Basics A jet engine can be divided into several distinct sections: intake, compressor, diffuser, combustion chamber, turbine, and exhaust. These sections are much like the different cycles in a four-stroke reciprocating engine: intake, compression, power and exhaust. In a four-stroke engine a fuel/air mixture is is brought into the engine (intake), compressed (compression), and finally ignited and pushed out the exhaust (power and exhaust). In it's most basic form, a jet engine works in much the same way. * Air comes in the front of the engine where it enters the compressor. The air is compressed by a series of small spinning blades aptly named compressor blades and leaves at a high pressure. The pressure ratio between the beginning and end of the compressor can be as much as 48:1, but almost always 12:1 or more. * The air now enters the diffuser, which is nothing more than an area where the air can expand and lower it's velocity, thus increasing its pressure a little bit more. * The high pressure air at the end of the diffuser now enters the combustion chamber where it is mixed with fuel, ignited and burned. * When the fuel/air mixture burns, the temperature increases (obviously) which makes the air expand. * This expanding gas drives a set of turbine blades located aft of the combustion chamber. At least some of these turbine blades are connected by a shaft to the compressor blades to drive them. Depending on the type of engine, there may be another set of turbine blades used to drive another shaft to do other things, such as turn a propeller or generator. * The left over energy not extracted by the turbine blades is pushed out the back of the engine (exhaust section) and creates thrust, usually used to drive an airplane forward. The types of jet engines include: * Turbojet * Turbofan * Turboprop * Turbo shaft Turbojet The turbojet is the simplest of them all, it is just as described in "The basics" section. This style was the first type of jet engine to be used in aircraft. It is a pretty primitive style used mostly in early military jet fighters such as the F-86. Its use was discontinued, for the most part, in favor of the more efficient turbofans. Actually, I should clarify that. Each type of engine is most efficient under certain conditions. Turbojets are most efficient at high altitudes and speeds above the speed of sound. See the diagram at the end of this page for relative efficiencies of each style engine. Turbofan Turbofans make up the majority of jet engines being produced and used today. A turbofan engine uses an extra set of turbine blades to drive a large fan, typically on the front of the engine. This fan differs from a propeller in that there are many small blades and they are inside of a duct. The fan sits just in front of the normal intake, some of the air driven by this fan will enter the engine, while the rest will go around the outside. The amount of air that bypasses the engine is different for each type of airplane. The different styles are called high and low bypass engines. Bypass ratio is the ratio of how much air goes through the fan, to how much goes through the engine. Typical bypass ratios would be 1:1 for a low bypass and 5:1 or more for a high bypass. Low bypass engines are more efficient at higher speeds, and are used on planes such as military aircraft, while high bypass engines are used in commercial airliners. Turboprop Turboprops are similar to turbofans in that they incorporate an extra set of turbine blades used to drive the propeller. Unlike the turbofan engines, nearly all the thrust produced by a turboprop is from the propellor, hardly any thrust comes from the exhaust. These engines are used mostly on smaller and slower planes such as commuter aircraft that fly to the smaller airports. As you can see from the efficiency chart below, turboprops are very efficient over a fairly wide range of speeds. They would probably be used more often on large transport aircraft, except for one problem: they have propellors. The general public does not like propellors, as they appear to be old-fashioned and unsafe. However, the military knows better and uses them on several large transport aircraft. Turbo shaft Turbo shaft engines are very similar to turboprop engines, but instead of driving a propellor, they are used to drive something else. Many helicopters use them to drive their rotors, and airliners and other large jets use them to generate electricity. Also, the Alaska Pipeline uses them at the pump stations to pump oil. Overall Overall the big difference between these engines is how they take a chunk of air and move it. Newton's third law states that Force equals mass times acceleration. Applying this to turbine engines: the turboprop takes a large chunk and accelerates it a little bit, while the turbojet takes a small chunk and accelerates the heck out of it, and the turbofan is somewhere in between these two. These different methods of moving air also have to do with how much noise each engine makes. The turbojet makes the most noise because there is a large difference in velocities of the blast of air coming out the exhaust and the surrounding air. The air from the fan on a turbofan engine "shields" the blast in the center by having the slower moving air from the fan surround it. Then the turboprop is the quietest of all because the air it's moving is relatively slow. A pressure - volume diagram (or a P-V diagram) is a useful tool in thermodynamics. In this case, it relates the pressure and volume of the gas moving through the engine at different stages. A P-V diagram can also be helpful in finding the work output of an engine. Work equals the integral of pressure with respect to volume. Or is simpler form, work equals the area enclosed in the diagram above. The above cycle is the Brayton cycle, or the cycle used by aircraft gas turbine engines. Explanation of the above cycle: * Air enters the inlet at point 1 at atmospheric pressure. * As this air passes through the compressor (from point 1 to 2), the pressure rises adiabatically (no heat enters or leaves the system). * Now the air enters the combustion chamber (from point 2 to 3), is mixed with fuel, and burned at a constant pressure. * Finally, the air goes through the turbine and out the exhaust (point 3 to 4) where the gases expand and do work. Thus, the pressure drops and the volume increases. The Compressor There are two main styles for turbine compressors: the axial and the centrifugal. The Axial Compressor * The axial type compressor is made up of many small blades, called rotor vanes, arranged in rows on a cylinder whose radius gets larger towards the back (as can be seen from the above picture). These blades act much like small propellors. * In between these rotor vanes are stator vanes which stay in a fixed spot and straighten the air coming out of the previous stage of rotor vanes before it enters the next stage. * On some newer engines, the angle of these stator vanes can be adjusted for optimum efficiency. * Each stage (1 row of rotor and stator vanes) generally provides for a pressure rise of about (so after the first stage, the pressure would be above atmospheric, after the second it would be , , etc...). The Centrifugal Compressor * Air enters the centrifugal compressor at the front and center. The blades then sling the air radially outwards where it is once again collected (at a higher pressure) before it enters the diffuser. * Pressure rise per stage is usually about 4 to 8:1 (higher than axial). These can be sombined in series (that is the exit of the first leads to the entrance of the next) to produce a greater pressure rise. But more than two stages is not practical. - Jet engines are rated in "pounds of thrust," while turboprops and turboshaft engines are rated in "shaft horsepower" (SHP). This is because it is difficult to hook up a dynamometer (power measuring device) to the column of air coming out of a jet engine, while it is easy to hook one to the shaft of a turboprop. - An equivalent measure to horsepower is thrust horsepower (THP). THP = (Thrust x MPH) / 375. or THP = SHP x 80% in the case of turboprop engines (the 80% is because the propeller "slips" a little in flight). - Exhaust gases exit the exhaust at upwards of 1000 mph or more and can use 1000 gallons of fuel/hour or more. - Turbine engines run lean. Unlike gasoline engines, turbines take in more air than they need for combustion. - Fuel can be injected into the exhaust section to burn with this unused air for extra thrust. This is called an afterburner. - A water/methanol mixture can be injected into the intake to increase the air density, and thus increase thrust. - Turbine engines can be built on a small scale as well. The turbine pictured below has a diameter of 4mm and runs at 500,000 rpm. It was built by at MIT for purposes of powering an aircraft with a wing span of about 5 inches that was projected to fly about 35 - 70 mph with a range of about 40 - 70 miles. micro turbine - The ignition system on turbine engines is only necessary for starting, afterwards it is self sustaining. In jets, the ignition system is also turned on for added saftey in "critical" stages of flight, such as takeoff and landing. - A device similar to a spark plug is used for the ignition process, but it has a larger gap. The spark is about 4 to 20 Joules (watts/second) at about 25000 volts and occurs between 1 and 2 times per second. - Turbine engines will run on just about anything, they prefer Jet-A (AKA diesel, kerosene, or home heating oil), but can burn unleaded, burbon, or even very finely powdered coal! - The above snowmachine uses an Allison turbine engine, a very common engine in helicopters (such as the Bell 206 Jet Ranger shown below). A lot of horsepower can be put into a small package! Note the intake and compressor are at the front of the engine, then the two side tubes take the compressed air and bring it around back to the combustion chamber and turbine and the exhaust exits out the middle. There are many engines out there with strange configurations like this. Communications Technology Your Rights and what the Data Protection Commissioner can do to help Right of Access The personal information to which you are entitled is that held on computer or in a manual filing system that facilitates access to information about you. You can make an access request to any organisation or any individual who has personal information about you. For example, you could make an access request to your doctor, your bank, a credit reference agency, a Government Department dealing with your affairs, or your employer. If you find out that information kept about you by someone else is inaccurate, you have a right to have that information corrected (or "rectified"). In some circumstances, you may also have the information erased altogether from the database - for example, if the body keeping the information has no good reason to hold it (. it is irrelevant or excessive for the purpose), or if the information has not been obtained fairly. You can exercise your right of rectification or erasure simply by writing to the body keeping your data. In addition, you can request a data controller to block your data . to prevent it from being used for certain purposes. For example, you might want your data blocked for research purposes where it held for other purposes. If an organisation holds your information for the purposes of direct marketing (such as direct mailing, or telephone marketing), you have the right to have your details removed from that database. This right is useful if you are receiving unwanted "junk mail" or annoying telephone calls from salespeople. You can exercise this right simply by writing to the organisation concerned. The organisation must write back to you within 40 days confirming that they have dealt with your request. Right to complain to the Data Protection Commissioner What happens if someone ignores your access request, or refuses to correct information about you which is inaccurate? If you are having difficulty in exercising your rights, or if you feel that any person or organisation is not complying with their responsibilities, then you may complain to the Data Protection Commissioner, Mr Mead, who will investigate the matter for you. The Commissioner has legal powers to ensure that your rights are upheld. The Data Protection Commissioner will help you to secure your rights: * with advice and information * by intervening directly on your behalf if you feel you have not been given satisfaction * by taking action against those failing to fulfil their obligations. SEE APPENDIX 2 FOR CASE STUDY Ergonomics Ergonomics (from Greek ergon work and nomoi natural laws) is the study of designing objects to be better adapted to the shape of the human body and/or to correct the user's posture. Common examples include chairs designed to prevent the user from sitting in positions that may have a detrimental effect on the spine, and the ergonomic desk which offers an adjustable keyboard tray, a main desktop of variable height and other elements which can be changed by the user. Ergonomics also helps with the design of alternative computer input devices for people who want to avoid repetitive strain injury or carpal tunnel syndrome. A normal computer keyboard tends to force users to keep their hands together and hunch their shoulders. To prevent the injuries, or to give relief to people who already have symptoms, special split keyboards, curved keyboards, not-really-keyboards keyboards, and other alternative input devices exist. Ergonomics is much larger than looking at the physiological and anatomical aspects of the human being. The psychology of humans is also a key element within the ergonomics discipline. This psychological portion of ergonomics is usually referred to as Human factors or Human factors engineering in the ., and ergonomics is the term used in Europe. Understanding design in terms of cognitive workload, human error, the way humans perceive their surrounds and, very importantly, the tasks that they undertake are all analysed by ergonomists. [IMAGE] With video conferencing consideration should be taken in positioning of camera and screens so as to avoid neck strain. Codec 1. (COder/DECoder or COmpressor/DECompressor) Hardware or software that encodes/compresses and decodes/decompresses audio and video data streams. The purpose of a codec is to reduce the size of digital audio samples and video frames in order to speed up transmission and save storage space. The goal of all codec designers is to maintain audio and video quality while compressing the binary data further. Speech codecs are designed to deal with the characteristics of voice, while audio codecs are developed for music. Codecs may also be able to transcode from one digital format to another; for example, from PCM audio to MP3 audio. The codec algorithms may be implemented entirely in a chip or entirely in software in which case the PC does all of the processing. They are also commonly implemented in both hardware and software where a sound card or video capture card performs some of the processing, and the main CPU does the rest. When analog signals are entered into a computer, cellphone or other device via a microphone or video source such as a VHS tape or TV, analog-to-digital converters create the raw digital audio samples and video frames. Speech, audio and video codecs are typically lossy codecs that compress data by altering the original format, which is why "codec" means "encoder/decoder" and "compressor/decompressor." If a codec uses only lossless compression in which the original data is restored exactly, then it would not be a coder/decoder. This is a subtle point, but the two meanings of the acronym have been confusing. LAN A local area network (LAN) is a computer network covering a local area, like a home, office or small group of buildings such as a college. The topology of a network dictates its physical structure. The generally accepted maximum size for a LAN is 1000m2. LANs are different from personal area networks (PANs), metropolitan area networks (MANs) or wide area networks (WANs). LANs are typically faster than WANs. The earliest popular LAN, ARCnet, was released in 1977 by Datapoint and was originally intended to allow multiple Datapoint 2200s to share disk storage. Like all early LANs, ARCnet was originally vendor-specific. Standardization efforts by the IEEE have resulted in the IEEE 802 series of standards. There are now two common wiring technologies for a LAN, Ethernet and Token Ring. Wireless technologies are starting to evolve and are convenient for mobile computer users. A number of network protocols may use the basic physical transport mechanism including TCP/IP. In this case DHCP is a convenient way to obtain an IP address rather than using fixed addressing. LANs can be interlinked by connections to form a Wide area network. A router is used to make the connection between LANs. WAN WANs are used to connect local area networks together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organisation and are private, others, built by Internet service providers provide connections from an organisation's LAN to the Internet. WANs are most often built of leased lines. At each end of the leased line, a router connects to the LAN on one side and a hub within the WAN on the other. A number of network protocols may use the basic physical transport mechanism including TCP/IP. Other protocols including and ATM. Frame relay can also be used for WANs. Ethernet Ethernet is normally a shared media LAN. All stations on the segment share the total bandwidth, which is either 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet) or 1000 Mbps (Gigabit Ethernet). With switched Ethernet, each sender and receiver pair have the full using Ethernet the computers are usually wired to a hub or to a switch. This constitutes the physical transport mechanism. Fiber-optic Ethernet (10BaseF and 100BaseFX) is impervious to external radiation and is often used to extend Ethernet segments up to miles. Specifications exist for complete fiber-optic networks as well as backbone implementations. FOIRL (Fiber-Optic Inter Repeater Link) was an earlier standard that is limited to .6 miles distance.

空调压缩机过载保护的研究321前言空调器压缩机易受电压、制冷系统工况的影响，在不良的使用环境中，压缩机容易烧毁。作为空调器成本最高的部件，压缩机的保护技术成为空调技术领域必须关注的一个重要课题。在现有的压缩机的保护技术中使用最多的是用电流互感器或温度传感器检测技术，前者是利用电流互感器感应压缩机主电路的电流，通过电流的检测获知压缩机电流，当电流超过设定值时，通过软件的控制断开主回路保护压缩机，电流互感器可以装在室内机或室外机中；温度传感器检测技术是在压缩机的表面安装一个温度传感器，通过检测压缩机的温度来保护压缩机，由于压缩机线圈在内部，其表面与外部的温升相差甚远，温度测量误差较大，在瞬间的过流中，保护效果不理想。以上两种技术需要单片机控制，而且在室内机与室外机之间要增加一至两条连接线，制造成本较高。从有关的实验中发现，压缩机烧毁往往出现在缺少制冷剂并在恶劣的使用环境工况下，压缩机线圈温度与进气压力、制冷剂的数量有关。本文主要讨论在常用的空调器室内机的软件、硬件不变的情况下，利用压力开关作为压力检测器件，在室外机的闲置的空间增加一个检测的电控板，通过对压缩机的压力检测实现压缩机的过载保护。采用这种方案，无需对空调器的原有电路进行更改，通用性极强，可应用于不同型号的空调器，而且室内机无需变化。2控制方案及实现方法电路原理压缩机压力检测电路原理包括：在压缩机的进气管安装压力开关，以及在室外机安装一个电控板，电控板主要包含5个部分：阻容降压电路、压缩机延时电路、外风机转换电路、压力开关转换电路、三极管控制电路，利用压缩机、外风机、压力开关的信号，通过硬件电路自动实现压缩机进气压力过低等不正常的压力保护，在保护的过程中，不影响空调的启动和空调的除霜。图1为压缩机保护装置检测结构方框图，图2为压缩机保护装置电气原理图。阻容降压电路主要由电阻、电容、压敏电阻、稳压二极管组成，输入端与压缩机线相连接，其作用是将220V的交流电转为低压的12V直流电，作为各电路的供电电源，输出端的12V供给比较器及其偏图1压缩机保护装置检测结构方框原理图置电路、三极管、压力开关等器件，阻容降压电路省略了变压器，成本极低。压缩机延时电路。该电路是保证压缩机运行的前5分钟能正常运行，由于压缩机刚开启的头3分钟，进气管的压力偏低，压力开关打开，压力开关转换电路会出现低压保护信号。压缩机延时电路与压力开关转换电路为并联关系，图3为压缩机延时电路控制逻辑示意图。压缩机开启后，阻容降压电路输出12V供给压缩机延时电路，由于C 3 0 7正在充电，IC304A的2脚输出低电平，当压缩机得电后约5分钟，C307充满电，IC304A的2脚输出由低电平转为高电平，这样压缩机延时电路相当于一个延时5分钟的开关，在压缩机开启头5分钟闭合，超过5分钟后打开，这样保证了压缩机开启的头3分钟能正常运行。外风机转换电路：压缩机除霜时间一般为8至10分钟（如图2），大功率的压缩机除霜期间，进气口处于低压力的时间较长，致使压力开关打开，然而压缩机延时电路只能延时5分钟，这样会出现压缩机除霜超过5分钟后不能除霜的现象，所以需要加入一个外风机转换电路。以比较器芯片为主构成的外风机转换电路相当一个非门电路，图4为外风机转换电路控制逻辑示意图。当外风机线得电时，转换电路输出为高电平；反之转换电路输出为低电平。正常的制热或制冷工况下，外风机得电，IC303光耦PC817导通，IC305C的14脚为高电平；在除霜期间外风机关闭，IC303光耦PC817截止，IC305C的14脚为低电平，这时不论压力开关转换电路处于何种工作状态，压缩机仍可运。压力开关转换电路。将压力开关的进气孔和出气孔串接在压缩机低压的进气管路中，当制冷剂泄漏造成不足，且空调器运行在恶劣的环境工况中，造成压力过低时，压力开关打开，反之，压力开关闭合，有图与我索取全文免费

轮机工程技术论文范文篇二 燃气轮机在热电联产工程中的应用状况分析 摘要： 燃气轮机是21世纪乃至更长时间内能源高效转换与洁净利用系统的核心动力装备.介绍了燃气轮机的发展现状及其在热电联产工程中的应用，简述了联合循环和简单循环燃气轮机电厂的基本组合方式，并列举了目前应用在热电联产工程中的几种主要的燃气轮机.阐述了燃气轮机相对于常规火电机组的优点，分析了影响燃气轮机在热电联产工程中推广的因素，并对我国燃气轮机的发展前景进行了展望. 关键词： 燃气轮机; 联合循环电厂; 热电联产 中图分类号： TK 479文献标志码： A Analysis of the application of gas turbines in heat and power cogeneration projects SUN Peifeng， JIANG Zhiqiang (1. China United Engineering Corporation， Hangzhou 310022， China; 2. China Huadian Corporation， Beijing 100031， China) Abstract： The gas turbine is the core equipment of highefficiency clean energy systems in the 21st century and even longer period of time. The current situation of gas turbine development and its application in heat and power cogeneration projects were showed in this paper. Two types of application of gas turbines in heat and power cogeneration projects were briefly introduced， namely， the simple cycle gas turbine power plant and the combined cycle power plant， and gas turbines widely used at present in heat and power cogeneration plants were enumerated. The advantages of the gas turbine plant compared with conventional coalfired power units were described and factors which could influence the application of the gas turbine were analyzed. In addition， the prospects for the development of gas turbines in China were evaluated. Key words： gas turbine; combined cycle power plant; heat and power cogeneration 燃气轮机由压气机、燃烧室、透平、控制系统和辅助设备组成.燃气轮机的设计是基于布莱顿循环.压气机(即压缩机)连续地从大气中吸入空气并将其压缩;压缩后的空气送入燃烧室，与喷入的天然气混合，并点火燃烧;燃烧后产生的高温烟气随即流入燃气透平中膨胀做功，推动透平带动压气机叶轮一起旋转.加热后的高温燃气的做功能力显著提高，因此，透平在带动压气机的同时，还有余功作为燃气轮机的输出功输出. 由于燃气轮机的工质是高温烟气而不是水蒸气，故可省去锅炉、冷凝器、给水处理等大型设备.因此，燃气轮机电厂附属设备较少，系统简单，占地面积较少. 燃气轮机可分为重型燃气轮机、工业型燃气轮机和航改型燃气轮机三类.重型燃气轮机的零件较为厚重，大修周期长，寿命可在10万h以上，主要用于满足城市公用电网需求，例如日立的H25和H80系列燃气轮机、通用电气的F级燃气轮机、西门子的SGT-8000系列燃气轮机、三菱的M701系列燃气轮机和阿尔斯通的GT系列重型燃气轮机等.工业型燃气轮机的结构紧凑，所用材料一般较好，燃气轮机的效率较高，例如索拉的T130燃气轮机和西门子SGT-800燃气轮机，常用于热电联产工程.航改型燃气轮机是由航空发动机改装而成的燃气轮机，在航空领域运用较多，但也有应用于发电及相关工业领域，例如通用电气的 LM 系列航改型燃气轮机等.航改型燃气轮机的结构最紧凑，最轻巧，效率最高，但寿命较短[1-2]. 燃气轮机自上世纪30年代诞生以来发展迅速.当今国际上最新型的G型燃气轮机和H型燃气轮机，单机功率已达到292～334 MW，发电热效率已达到.其中，由G型燃气轮机组成的联合循环单机功率可达489 MW，发电热效率可达;由H型燃气轮机组成的联合循环机组的发电热效率可达60%[3-5].H型燃气轮机组成的联合循环机组是目前已掌握的热-功循环效率最高的大规模商业化发电方式.不仅如此，燃气轮机与以煤为燃料的蒸汽轮机相比，它具有重量轻、体积小、效率高、污染少、启停灵活等优点.燃气轮机发电机组能在无外界电源的情况下迅速启动，机动性好.在电网中用它带动尖峰负荷和作为紧急备用电源，还能携带中间负荷，能较好地保障电网的安全运行，所以得到广泛应用[6]. 国内外科技界与产业界已经认识到燃气轮机将是21世纪乃至更长时期内能源高效转换与洁净利用系统的核心动力装备. 1燃气轮机在热电联产工程中的应用方式 燃气轮机在热电联产工程中的应用形式主要有两种：一种是燃气轮机联合循环热电厂;另一种是燃气轮机简单循环热电厂. 燃气轮机联合循环热电厂由燃气轮机、余热锅炉、蒸汽轮机(背压式、抽背式或者抽凝式)和发电机共同组成.燃气轮机排出的做功后的高温烟气通过余热锅炉回收烟气中的热量而得到高温水蒸气，水蒸气注入蒸汽轮机发电.蒸汽轮机的排汽或者部分在蒸汽轮机中做功后的抽汽用于供热，形式有：燃气轮机、蒸汽轮机同轴推动一台发电机的单轴联合循环;燃气轮机、蒸汽轮机推动各自的发电机的多轴联合循环.单轴的燃气轮机联合循环电厂规模较大，例如通用电气的9F系列机组.而多轴的联合循环机组常见于中小型的燃气轮机联合循环电厂.因此，对于电厂规模相对较小的热电联产工程来说，常选择多轴的燃气轮机联合循环机组. 燃气轮机简单循环热电厂由燃气轮机和余热锅炉组成.该类型燃气轮机热电厂不配置蒸汽轮机，通过余热锅炉直接对外供热.因此该类型燃气轮机热电厂发电热效率相对联合循环燃气轮机热电厂较低，约为30%～35%之间;热电比和供热成本的指标方面，简单循环燃气轮机热电厂也低于联合循环燃气轮机热电厂[7]. 由此可见，燃气轮机联合循环可大大提高发电厂整体发电热效率.即使只有燃气轮机和余热锅炉组成的不配置蒸汽轮机的简单循环燃气轮机发电厂，其发电效率也高于常规的小型燃煤热电厂. 2热电联产工程中燃气轮机机型选择 热电联产工程遵循“以热定电”原则，首先满足外界对蒸汽负荷的需求，一般对发电量的需求相对较少.因此，对于热电联产工程来说，大功率的重型燃气轮机使用相对较少，常配置一些中小型的燃气轮机. 世界主要的中小型燃气轮机有：索拉的T130燃气轮机;日立的H25和H80燃气轮机;通用电气的6F和LM系列的航改型燃气轮机;西门子的SGT-800燃气轮机.各机型的主要技术参数如表1(见下页)所示(表中数据来自各个燃气轮机厂家产品宣传手册，且会因计算的天然气热值等参数变化而发生微小的变化). 表1各中小型燃气轮机相关性能参数 Performance parameters of some gas turbines 表1中，H25，H80 和6F为重型燃气轮机;SGT-800和T130为工业型燃气轮机;LM6000为航改型燃气轮机.从表1可知，工业型和航改型燃气轮机单机发电热效率相对重型燃气轮机的单机发电效率明显更高，但燃气轮机的排烟温度相对较低.由于排到余热锅炉的高温烟气所包含的热量相对较少，因此对于整个联合循环热电厂，工业型和航改型燃气轮机联合循环热电厂的整体发电热效率反而低些[8-9].简单循环的燃气轮机热电厂若选择工业型燃气轮机及航改型燃气轮机，其热电厂发电热效率会较高. 对于配置蒸汽轮机的燃气轮机联合循环，重型燃气轮机因其排烟温度较工业型燃气轮机和航改型燃气轮机高，排到余热锅炉的高温烟气所包含的热量相对较多，余热锅炉产出的供蒸汽轮机发电用的高温高压的蒸汽也更多.因此，重型燃气轮机联合循环整体发电热效率比工业型燃气轮机和航改型燃气轮机联合循环的发电热效率高.燃气轮机联合循环热电厂中大多选择重型燃气轮机. 从能量的充分利用和逐级利用角度讲，相比于燃气轮机简单循环热电厂，燃气轮机联合循环热电厂更具有优势.目前我国燃气轮机热电联产工程中，大多选择重型燃气轮机组成的联合循环燃气轮机热电厂，如浙江省的某热电厂，采用6F级燃气轮机匹配余热锅炉和蒸汽轮机组成燃气轮机联合循环机组对外供热供电，燃气轮机联合循环热电厂整体发电热效率约60%. 但是对于某些对占地面积有严格要求的场合，如海上油气平台井等，一般可选择结构紧凑、效率高的工业型燃气轮机或者航改型燃气轮机机. 具体燃气轮机机型的选择可根据各工程的实际情况进行分析、计算、确定，如热电厂的对外供热参数和供热量、装机容量、机组数量、占地面积、整体热效率等. 3燃气轮机联合循环热电联产工程相对于常规火力发电热电联产的优势[10] 相对于常规燃煤的小型火力发电的热电联产电厂，燃气轮机联合循环热电厂的优势主要有： (1) 高效：燃气轮机联合循环的发电热效率已经达到甚至突破60%，这是一般常规火电机组无法比拟的，甚至高于目前最先进的超超临界机组而稳居各类火电机组之首. (2) 单位造价低：燃气轮机联合循环机组单位容量造价约400美元·kW-1，而常规火电机组造价为600～1 000美元·kW-1;若我国国产燃气轮机的制造加工水平进一步提升，燃气轮机联合循环机组单位容量造价还有非常大的下降空间. (3) 低排放：燃气轮机联合循环不排放SO2以及飞灰和灰渣;NOx的排放量也非常低，一般都可以达到 mg·m-3以下，甚至可以根据需要达到小于 mg·m-3的水平，CO2的排放量可以做到 mg·m-3;环保性能居于现有各种火电机组之上. (4) 节水：燃气轮机联合循环机组以燃气轮机发电为主，燃气轮机发电机功率占总容量的70%，联合循环机组所需用水量约为常规燃煤机组的1/3.这在某些缺水的地区显得尤为重要.若选择燃气轮机和余热锅炉配置的简单循环，整个电厂对机组冷却水量的需求相对于常规火电厂的冷却水量更是大幅度减少. (5) 省地：燃气轮机联合循环机组因附属设备较少，无需储煤场、输煤设施，占地面积仅为加脱硫装置的常规火电厂的1/3.这在城市边缘及城区的供热电厂显得尤为重要. (6) 建设工期短：燃气轮机联合循环机组最适合模块化设计，燃气轮机各部件模块可工厂化生产，运至现场吊装，因而大大缩短了燃气轮机电厂的建设工期. (7) 调峰性能好：通过余热锅炉的旁路烟囱，不运行蒸汽轮机及发电机组的情况下，一般在20 min 内就能达到燃气轮机及发电机组的100%负荷，而燃气轮机及其发电机组负荷占整个燃气轮机联合循环电厂额定负荷的70%左右，这保证了燃气轮机联合循环的良好调控性能，实现机组的日启夜停和调峰功能. (8) 操作运行和维护人员少：因为燃气轮机联合循环电厂自动化程度高，采用先进的控制系统，电厂对员工数量的需求大幅下降.一般情况下占同容量常规燃煤电厂人员的20%～25%就足够了. 4影响燃气轮机在热电联产工程中推广的主要因素 燃气轮机联合循环电厂在国外已经得到了普遍发展，近几年已占据美国电力市场的重要地位，欧洲的燃气轮机联合循环电厂也获得了长足的发展.目前我国燃气轮机联合循环电厂能否获得大力推广和发展，主要受制于如下三个因素： (1) 我国能提供多少天然气资源供燃气轮机发电工业使用;当前国内已有部分燃气轮机联合循环电厂因受制于燃料供应，每年运行的时间远远少于常规燃煤机组. 2012年，随着“西气东输”二线最后几条干线的建成投产，整个输气管道实现每年输气300亿m3.未来中国甚至有可能规划修建“四线”或者“五线”，进一步便于西部地区的天然气输送到东部地区开发利用. 另外，海上(东海、南海)天然气的开发、沿海港口城市液化天然气(LNG)的进口，也为联合循环发电扩充了气源供应条件.国内已经探明了华北、东北、西北三大煤层气资源储量，并将逐步开采. 随着天然气来源渠道的扩大，燃气轮机联合循环电厂的应用范围将大大突破西气东输管网和海上天然气所能影响的地区. (2) 如何合理确定天然气价格，使燃气轮机联合循环发电成本能够与严重污染的以煤为燃料的常规火电相竞争. 必须指出，天然气的价格对燃气轮机及联合循环的运行成本有着决定性的影响.在燃气轮机三项发电成本的组成中(设备折旧成本、机组运行维护成本、燃料成本)，燃料成本的比例高达60%～65%，即使在天然气的产地，运输过程费用大为降低，天然气价格相对东南沿海地区更加便宜，其成本占燃气轮机发电成本的比例仍然是非常高的[4].在天然气价格居高不下的今天，燃料成本高已经成为制约燃气轮机发电大力推广的一个关键性因素. 当前，作为工业企业及城市基础设施的重要组成部分的许多中小型燃煤热电厂，通常地处城市之中或者城市郊区，因此不可避免地会对当地大气环境质量产生很大影响.中小型燃煤热电厂改造为燃气轮机联合循环热电厂，对当地环境质量的改善效果非常明显，也最容易得到人民群众的接受和支持. 热电厂的燃料从煤炭改造为天然气，虽然合理调整了能源结构，提高了能源利用效率，减少了煤炭运输环节的损失和浪费，但是对燃气轮机联合循环热电厂来说，燃料成本必然要增加，能源代价必然会提高，因此争取群众和企业的理解和参与，合理分担部分天然气成本因素，是解决天然气市场和成本关系的一条合理途径. 政府在制定燃气轮机联合循环热电厂上网电价和外供蒸汽价格时，应考虑到燃气轮机的环境效益，适当提高上网电价和外供蒸汽价格，这也是对天然气成本过高的一种消化. (3) 从长远的角度看，我国燃气轮机整体行业水平的提高是决定我国燃气轮机及联合循环电厂能否大力推广的一个重要因素. 燃气轮机的发展水平代表着一个国家的重大装备制造业的总体水平.当前我国的燃气轮机技术水平与世界先进水平之间的差距还很大，燃气轮机的核心部件依赖于进口，燃气轮机的每次大修花费很大.若某些燃气轮机的大修只能运回美国等发达国家进行，则其费用更大. 近年来，为了推动燃气轮机工业的发展，按照“市场换技术”的原则，我国对规划批量建设的燃气轮机发电站工程项目采取“打捆”式招标采购模式，由国外先进燃气轮机制造企业与国内制造企业相互结合组成联合体，进行燃气轮机联合循环电站工程项目的竞争投标，以吸收和引进国外先进技术.在这一过程中，我国同时引进了世界三大动力集团(通用电气、西门子、三菱)的F级重型燃气轮机.在实现燃气轮机设备制造本土化和国产燃气轮机技术开发方面都取得了良好的成果.在吸收和引进国外先进燃气轮机技术的基础上，逐步实现了燃气轮机联合循环电站设备研发和制造的国产化、本地化和知识产权自主化[11-12]. 2008年，我国具有完全自主知识产权的110 MW级R0110燃气轮机进行了点火及实验验证，其性能已经接近于目前国际上先进的F级燃气轮机，对我国的燃气轮机设计、制造和加工的整体水平是一个巨大的提升[13-14]. 目前，我国燃气轮机技术水平与国际先进水平之间的差距正在不断缩小，我国的燃气轮机自主研发、生产制造等方面取得了重大进展.2012年9月12日，上海市科委重大专项课题“高温合金叶片制造技术研究”通过专家验收，这标志着我国在燃气轮机核心部件国产化、自主化生产的道路上迈出了坚实的一步. 从制约燃气轮机联合循环电厂发展的三个因素及我国目前的相应情况可知，我国大力发展燃气轮机联合循环的条件已经具备，燃气轮机联合循环电厂的快速发展在近期将成为可能. 5总结 实现节能减排，提高能源利用率是我国能源结构调整的目标.随着我国天然气资源的开发、利用及液化天然气资源的引进，我国燃气轮机联合循环机组将不断增加.燃气轮机联合循环以其高效、清洁和灵活的特点，必将成为我国未来大力发展的电厂类型. 目前可用于热电联产的中小型燃气轮机容量和整个热电厂供热能力与我国广泛使用的蒸汽轮机热电机组的规格十分接近，因而可在不改变外部系统，不增加发电容量和不间断供热、发电的前提下，以较短的时间、较低的投资和较合理的电、热成本实现对热电厂以气代煤的改造.这也是燃气轮机联合循环热电厂可获得大力推广的现实条件. 总之，燃气轮机联合循环机组在我国电力工业中的作用将逐渐增强，发展燃气轮机联合循环热电厂任重而道远，但是前景是非常光明的. 参考文献： [1]李孝堂.燃气轮机的发展及中国的困局[J]，航空发动机，2011，37(3)：1-7. [2]马悦，纪锦锋.燃气-蒸汽联合循环电站机组配置及选型分析[J].能源工程，2011(6)：52-57. [3]蒋洪德.重型燃气轮机的现状和发展趋势[J].热力透平，2012，41(2)：83-88. [4]清华大学热能工程系动力机械与工程研究所，深圳南山热电股份有限公司.燃气轮机与燃气-蒸汽联合循环装置[M].北京：中国电力出版社，2007. [5]刘红，蔡宁生.重型燃气轮机技术进展分析[J].燃气轮机技术，2012，25(3)：1-5. [6]张荣刚，李文强.浅析燃气轮机在电力行业中的应用[J].企业技术开发，2011，30(10)：122-123. [7]徐迎超，阎波，樊泳，等.燃气-蒸汽联合循环(CCPP)发电在首钢迁钢公司中的应用[J].冶金动力，2012(1)：27-29. [8]刘祖仁，李达，张阳.海上燃气轮机余热资源计算[J].中外能源，2012，17(5)：99-103. [9]李达，张阳，孙毅.海上冷、热、电、惰气四联供护技术探讨[J].石油和化工节能，2012(5)：11-14. [10]黄勇.我国发展联合循环机组的背景和条件[J].中国科技博览，2011(29)：372. [11]刘华强，汪晨晖.燃气轮机在我国应用情况分析[J].中国新技术新产品，2012，(6)：149. [12]杨连海，沈邱农.大型燃气轮机的自主化制造[J].燃气轮机技术，2006，19(1)：11-14. [13]崔荣繁，陈克杰，郭宝亭.R0110重型燃气轮机的研制[J].航空发动机，2011，37(3)：8-11. [14]包大陆.R0110重型燃气轮机气缸结构研究[J].中国新技术新产品，2012(9)：109. 看了“轮机工程技术论文范文”的人还看： 1. 轮机工程技术个人简历免费模板 2. 船舶轮机管理论文 3. 船舶最新技术论文 4. 农业机械技术论文 5. 电厂工程技术管理论文

一、概述 可编程控制器（PLC）是一种新型的通用控制装置，他将传统的继电器控制技术、计算机控制技术和通信技术融为一体，专为工业控制而设计，具有功能强、通用灵活、可靠性强、环境适应性好、编成简单、使用方便、体积小、重量轻、功耗低等一系列优点。近年来，随着可编程控制器的日渐成熟，越来越多设备的控制都采用PLC控制器来代替传统的继电器控制，并取得了很好的经济效益。空气压缩机使矿山生产重要的四大固定设备之一，它生产压缩空气，用以带动凿岩机、风动装岩机等设备及其他风动工具。其能否安全运行直接影响着煤矿生产的产量和效益问题。影响其安全生产的要素主要有空压机的超温、超压、断水、断油等因素。随着煤矿现代化的发展，矿山对矿山设备的要求越来越高,建设本质安全性矿山已成为煤矿生产建设的核心。矿山设备不断更新，不断进步，可靠性、易操作性、可监视性、易维护性等已是最基本的要求了。用继电器搭成的控制电路具有可靠性差、不易维护、不易监视，已不能适应当前的要求。现在迫切需要可靠性高、易维护、易操作、可监视并且价格不高这样的控制器来代替继电器搭成的电路。随着电子技术、软件技术、控制技术飞速发展，可编程控制器（PLC）发展迅猛，性能很高，价格较为合理，与继电器搭的控制电路比具有非常大的优势。许多矿山设备已选用了PLC来代替比较重要的设备控制。传统的保护主要采用分离仪表，其可靠性差、集程度低、费用高，不能有效的满足矿山设备投入的经济性和安全性的要求。本文笔者采用可编程控制器（PLC）作为核心控制器，通过检测仪器为PLC提供控制中所需要的信号参数对空压机进行自动巡回检测控制。进行监控的主要参数有空压机高低压缸温度、润滑油温度、电动机温度、风包温度、出水温度；高低压缸压力、风包压力、润滑油压力；高/低压、中/后冷却水断水检测等参数。二、控制功能和控制原理1. 保护控制功能⑴、 电机电流和电压的检测。⑵、 一二级缸、油压、风包压力检测。⑶、 一二级排气温度、油温、电机温度检测。⑷、 电动机的延时启动。⑸、 电机的无水运转。2. 保护控制原理在启动主机之前先将水源电磁阀和放空电磁阀都打开，在冷却水压和流量达到规定值条件下，可以进行空压机的空载起动，然后延时自动关闭放空电磁阀，空压机进行正常运行。启动时允许低油压启动，设置一定时间后对油压进行监控。在停机时，按复位按钮放空电磁阀打开，经30秒延时后切断主电源。实现空压机的停机，同时关闭水源电磁阀和放空电磁阀。在保户状态时，以上监控参数有一个在设定范围内发生故障，产生报警信号，同时打开放空电磁阀，压缩机减载运行，延时30秒故障不消除自动机停机。 ⑴. 控制分布图1-1压缩机控制分布图⑵. 控制通讯原理现场总线PROFIBUS可以实现数字和模拟输入/输出、智能信号装置和过程调节装置与可编程控制器PLC和PC之间的数据传输，把I/O通道分散到实际需要的现场设备附近。PROFIBUS一方面覆盖了传感器/执行器领域的通信要求，另一方面又具有单元级领域的所有通信网络通信功能。他支持高速的循环数据通信，以满足了实时监控的要求。1-2系统控制通讯图三、信号采集S7-200为每个本机数字量输入提供脉冲捕捉功能。脉冲捕捉功能允许PLC捕捉到持续时间很短的脉冲。而在扫描周期的开始，这些脉冲不是总能被CPU读到。当一个输入设置了脉冲捕捉功能时，输入端的状态变化被锁存并一直保持到下一个扫描循环刷新。这就确保了一个持续时间很短的脉冲被捕捉到并保持到S7-200读取输入点。本设计需对下列参数进行采集： (1)、压力信号分别为1级缸、2级缸及储风缸压力、润滑油压力4点； (2)、温度信号为1级缸排气温度、2级缸进气温度、风包温度、油温、电机温度以及冷却水出口温度共6点； (3)、电量信号为主电机电流1点，电源电压1点，共2个点。(4)、流量检测有高低/压端2点，中/后冷2点共4点。采集参数总计为4+6+2+4=16个。 对上述参数采集后，首先判断有关参数是否异常，然后形成动态数据表格进行实时巡回显示，并存储起来而供以后进行随机查询。四、系统软件设计本系统主要是以保护为主，根据《煤矿安全规程》的要求和空压机的保护原理，其控制的软件设计流如下。五、结束语该系统主要是以S7-200 为核心控制器，PROFIBUS作为通讯桥梁，通过检测元件为控制其提供检测信号，以此达到保护控制的目的。在本文的编写过程中，得到了张集矿机电科多位领导的大力支持，在此致以诚挚的谢意！同时感谢西门子（中国）有限公司自动化驱动集团提供的大量资料。