链条锅炉加煤粉复合燃烧节能改造

1　复合燃烧技术链条锅炉是一种常用的燃烧设备,在我国工业中广泛使用,目前75ｔ/ｈ以下蒸汽锅炉及29ＭＷ以下热水锅炉多数采用此种锅炉(见图1)。链条锅炉虽然是一种较好的燃烧设备,但在使用中存在一定缺点,主要是当煤种多变、煤质不好时,造成出力不足,热效率偏低,运行较好时实际出力一般为额定出力的60%～70%,少数运行不好的仅在50%左右,实际热效率仅在60%左右。链条锅炉加煤粉复合燃烧技术的主要目的是为了强化炉内燃烧过程,提高锅炉燃烧效率及煤种适应性。从锅炉燃烧理论可知,保持炉膛足够高的温度是保证锅炉良好燃烧的首要条件,炉温高则…     

链条炉加煤粉双重燃烧的改造设计与运行

链条炉是古老的机械层燃炉之一。由于它具有结构简单和操作方便等优点,目前在我国中小型工业锅炉中链条炉被广泛采用,并在机械化锅炉中占有重要的地位。然而,链条炉对煤种有一定的适应性。我国煤质资源丰富,但煤质差异很大,煤质的变化将使锅炉出力和效率下降,尤其是在燃烧热值偏于下限的燃料时,就必须采用措施解决着火、排渣等问     

人造板厂链条炉喷砂光粉复合燃烧技术

针对人造板厂燃煤链条炉煤种适应性差、热效率普遍较低的现状，提出了将人造板生产过程的剩余物——砂光粉喷人炉膛进行悬浮燃烧，与链条炉上煤的层燃共同组成复合燃烧的技术改造方案，该项技术可显著提高链条炉的煤种适应性，改善燃烧状况，提高锅炉热效率；同时，将砂光粉作为燃料使用，不仅可以减少锅炉的燃煤消耗量，而且也可避免砂光粉对环境的污染。     

复合燃烧技术在抛煤机链条炉上的应用

老式抛煤机链条炉出力不足,热效率偏低,通过复合燃烧技术在抛煤机链条炉上的改造应用,可以有效的提高热效率和出力,节能降耗。     

分行(垄形)燃烧在链条锅炉上的探索和创新

链条锅炉属平面层燃方式,煤层为单面引燃,燃烧过程煤间无扰动,所以燃烧效率低下,对煤质要求高。根据层燃属扩散燃烧区的理论,欲提高煤炭的完全燃烧程度,就要加强燃煤与空气的混合,提高气体的扩散速度。分行垄形煤层燃烧突破了链条炉燃煤表面必须是平的常规框框,实现多面引燃,层煤间自动、有序拨火续煤,低氧和薄煤层燃烧,节煤、节电,提高锅炉热效率与出力达到环保的目的。只要闸门和分层布煤锅炉可用的煤质,改用分行垄形燃烧都可比原来节能10%以上。     

大力推广锅炉分层燃烧技术利用

１　引言据统计，全国在用４ｔ／ｈ以上正转链条炉排锅炉约４万台，由于受正转链条炉排锅炉燃烧设备的限制，锅炉运行普遍存在通风不良，蒸发量低（一般为额定出力的７０％～８０％），煤种适应性差，热效率低等问题。前拱着火较慢，煤着火点偏后，造成锅炉燃烧不完全，煤渣含碳量居高不下（一般为２５％～３０％）。生产用汽量较大时，负荷波动性也大，锅炉的应变能力较差，为了赶负荷，需司炉工频繁钩火，以改善通风，消灭火口，强化燃烧。对此，人们在寻找上述问题的症结过程中，习惯的思路往往是局限于强调改造炉拱，调节风量，变换煤质…     

复合燃烧技术在链条锅炉上的应用

针对链条锅炉普遍燃烧状况不好 ,热效率偏低的现状 ,提出了把复合燃烧技术引入链条锅炉的方案 ,将层燃与室燃两种方式结合起来 ,可大为改善目前链条锅炉的燃烧状况 ,提高锅炉的煤种适应性和热效率 ,最终达到节煤和环保的双重目的。     

KZL4-13型锅炉强化燃烧节能技术改造

文章着重叙述了KZL4—13型锅炉出力低、热效率低的原因,并提出KZL4—13型锅炉经过链条炉加喷煤粉复合燃烧技术改造及运行经验。     

KZL4—13型锅炉强化燃烧节能技术改造

文章着重叙述了ＫＺＬ４－１３型锅炉出力低,热效率低的原因,并提出ＫＺＬ４－１３型锅炉经过链条炉加喷煤粉复合燃烧技术改造及运行经验。     

利用循环流化床技术对链条炉排锅炉进行增容改造

1前言链条炉排锅炉在工业锅炉中应用广泛,数量也较多,随着锅炉燃烧技术的发展,链条炉排锅炉暴露出许多缺陷,如出力不足,煤种适应性差,炉排检修量大,燃烧效率偏低等。近年来,随着市场经济的发展,生产规模的扩大,原有链条炉排锅炉在出力方面远远满足不了生产的要求。因此急需对锅炉进行增容改造。由于燃烧技术的限制,链条炉排锅炉在原有燃烧方式的基础上进行增容改造有一定局限性,因此,利用循环流化床技术对链条炉排进行增容改造,是当前企业节能技术的重要举措。近年来,为满足用户的要求我公司先后对30多台10t／h－65t／h的链…     

一种高效率的内燃机燃烧模式

本文探讨了以双燃料发动机为代表的预混合和扩散燃烧共存的复合燃烧模式。认为这种燃烧模式兼有预混合燃烧和扩散燃烧的优点，而且有比传统的燃烧模式更高的热效率。实验证明，采用这种燃烧模式工作的发动机可以有比火花点火式发动机更高的压缩比，有比压燃式发动机更高的燃烧速率。最后对这种发动机的燃烧特性及获得较高热效率的原因进行了分析。     

Investigation of forward flow distributed combustion for gas turbine application

New innovative advanced combustion design methodology for gas turbine applications is presented that is focused on the quest towards zero emissions. The new design methodology is called colorless distributed combustion (CDC) and is significantly different from the currently used methodology. In this paper forward flow modes of CDC have been investigated for application to gas turbine combustors. The CDC provides significant improvement in pattern factor, reduced NO_x emission and uniform thermal field in the entire combustion zone for it to be called as an isothermal reactor. Basic requirement for CDC is carefully tailored mixture preparation through good mixing between the combustion air and product gases prior to rapid mixing with fuel so that the reactants are at much higher temperature to result in hot and diluted oxidant stream at temperatures that are high enough to autoignite the fuel and oxidant mixture. With desirable conditions one can achieve spontaneous ignition of the fuel with distributed combustion reactions. Distributed reactions can also be achieved in premixed mode of operation with sufficient entrainment of burned gases and faster turbulent mixing between the reactants. In the present investigation forward flow modes consisting of two non-premixed combustion modes and one premixed combustion mode have been examined that provide potential for CDC. In all the configurations the air injection port is positioned at the opposite side of the combustor exit, whereas the location of fuel injection ports is changed to give different configurations. Two combustion geometries resulting in thermal intensity of 5 MW/m³-atm and 28 MW/m³-atm are investigated. Increase in thermal intensity (lower combustion volume) presents many challenges, such as, lower residence time, lower recirculation of gases and effect of confinement on jet characteristics. The results are presented on the global flame signatures, exhaust emissions, and radical emissions using experiments and flowfield using numerical simulations. Ultra-low NO_x emissions are found for both the premixed and non-premixed combustion modes at the two thermal intensities investigated here. Almost colorless flames (no visible flame signatures) have been observed for the premixed combustion mode. The reaction zone is observed to be significantly different in the two non-premixed modes. Higher thermal intensity case resulted in lower recirculation of gases within the combustion chamber and higher CO levels, possibly due to lower associated residence time. The characteristics at the two thermal intensity combustors investigated here were found to be similar.     

A review on plasma combustion of fuel in internal combustion engines

In recent years, new ways of improving the combustion efficiency of fuel during gas turbine operations have been developed. The most significant has been the application of plasma technology for the combustion of fuel in gas turbine operations. Plasma is formed when gas is exposed to either high temperature or high‐voltage electricity. This technology is very promising and has proven to enhance the performance of gas turbines and reduce toxic emissions. Recent studies have shown the use of different types of plasma applications in gas turbine operations such as plasma torch, filamentary discharge, and nanosecond pulse discharge, whose results show that plasma technology has great potential in improving flame stabilization, the fuel/air mixing ratio, and flash point values of these fuels. These findings and advances have further provided new opportunities in the development of efficient plasma discharges for practical uses in plasma combustion of fuel for gas turbine operations. This article is a comprehensive overview of the advances and blind spots in the knowledge of plasma combustion of fuel during internal combustion engine operations. This review also focuses on applications, methods, and experimental results in plasma combustion of fuel in gas turbines.     

Droplet combustion in the presence of acoustic excitation

This experimental study focused on droplet combustion characteristics for various liquid fuels during exposure to external acoustical perturbations generated within an acoustic waveguide. The alternative liquid fuels include alcohols, aviation fuel (JP-8), and liquid synthetic fuel derived via the Fischer–Tropsch process. The study examined combustion during excitation conditions in which the droplet was situated in the vicinity of a pressure node (PN). In response to such acoustic excitation, the flame surrounding the droplet was observed to be deflected, on average, with an orientation depending on the droplet’s relative position with respect to the PN. Flame orientation was always found to be consistent with the sign of a theoretical bulk acoustic acceleration, analogous to a gravitational acceleration, acting on the burning system. Yet experimentally measured acoustic accelerations based on mean flame deflection differed quantitatively from that predicted by the theory. Phase-locked OH^∗ chemiluminescence imaging revealed temporal oscillations in flame standoff distance from the droplet as well as chemiluminescent intensity; these oscillations were especially pronounced when the droplets were situated close to the PN. Simultaneous imaging and pressure measurements enabled quantification of combustion-acoustic coupling via the Rayleigh index, and hence a more detailed understanding of dynamical phenomena associated with acoustically coupled condensed phase combustion processes.     

摆动式水平浓淡风煤粉燃烧器在670 t/h锅炉的应用研究

我厂2号锅炉(DG 670/13.7-8A)为四角切圆布置,一、二次风间隔布置,分上下两组,设计煤种为晋中贫煤.在实际运行中,煤质不稳定,锅炉着火和燃烧稳定性差.采用"摆动式水平浓淡风煤粉燃烧器"技术对燃烧器改造后,燃烧效率提高0.84%、在300 t/h时能稳定燃烧、炉膛无结渣,锅炉参数稳定.     

First and second thermodynamic-law analyses of hydrogen-air counter-flow diffusion combustion in various combustion modes

In this paper, from the viewpoints of both the first and the second law of thermodynamics, we conduct a comprehensive study on hydrogen-air counter-flow diffusion combustion in various modes. The effects of air inlet temperature (T_oxi) and effective equivalence ratio of fuel (φ) on the reaction zone structure and entropy generation of combustion are revealed over a wide range of T_oxi and φ. Through the present work, five interesting features of combustion of this kind, which are quite different from that reported in the literature, are presented. Especially, for the first time we divide various combustion modes in the φ − T_oxi map instead of the popular way used in previous studies. Such innovation can help judge the final combustion regime more straightforwardly for any given operative condition.     

准均质充气压缩点燃系统燃烧特性研究

准均质充气压缩点燃（QHCCI）燃烧系统是在柴油机上实现稀薄预混合气燃烧的有效方法，建立了一个燃烧过程准维数学模型，结合试验结果，对QHCCI系统的燃烧特性进行了研究。内容包括引燃柴油喷射定时对系统燃烧性能的影响，引燃柴油喷射量对系统的影响，以及发动机工作粗暴的特性。模拟结果与试验结果一致，并发现QHCCI燃烧系统的放热律曲线一般呈双峰，引起爆震的原因主要是引燃柴油喷射量大或喷射早造成上止点附近的大量剧烈燃烧造成的。     

无焰燃烧发展及研究现状

无焰燃烧是一种同时具备高效和低排放特点的燃烧技术,然而传统实现无焰燃烧所需的高温预热空气及高速射流两大重要条件,提高了整体工业设备实现无焰燃烧的复杂性,限制了该技术在更广阔领域的发展。本文综述了无焰燃烧燃烧机理与特性的研究发展,并提出了未来可能的发展趋势。分析发现：高温预热空气并不是实现无焰燃烧的必要条件,而通过高速射流提高炉内烟气循环率却必不可少;使用EDC模型结合GRI 3.0反应机理能在数值模拟中得到贴合实验数据的结果;气体、液体及固末燃料均可实现无焰燃烧,使用CH4/H2混合气体实现无焰燃烧可在提升燃烧稳定性的同时依旧保持低排放的特点;炉膛结构可很大程度上影响炉内流场进而影响无焰燃烧效果。因此,研究无需预热的无焰燃烧系统在降低工业成本的同时可增大燃料种类的选择性,通过设计合理的炉膛结构,营造良好的炉内流场在强化无焰燃烧效果的同时可一定程度降低对初始射流速度的要求,研究CH4/H2混合气体的燃烧机理具有十分重要的意义。     

锅炉氧煤无焰燃烧技术分析

氧煤燃烧是一种全新燃烧方式,将氧煤燃烧器的表观氧气浓度从30％提高到50％、将O2/CO2混合气改变为纯氧气与再循环CO2烟气分离、将喷嘴速度从50m/s左右提高到200 m/s左右组织炉膛烟气形成高倍率内循环,从而在炉膛内实现高温低氧的氧煤无焰燃烧状态,氧煤无焰燃烧技术能实现煤粉高效燃烧和较低NO浓度排放的统一,锅炉...     

掺氢对微尺度空间内预混层流火焰转捩爆燃特性的影响

针对基于燃烧的微小型动力装置存在燃烧效率低、火焰传播速度慢的问题,设计了一个可视化的、特征间距仅为0.45 mm的微尺度定容燃烧室,实验比较了0~1的掺氢比例下,丙烷/氢气/空气预混火焰在该燃烧室内的传播以及加速过程.实验发现没有掺氢时,丙烷/空气预混火焰需要在0.25 MPa初始压力下才能够传播;当掺氢比例为0.2时,火焰在传播过程中会发生从缓燃到爆燃的转变,这种燃烧模态的转变可以大幅缩短燃烧室内火焰传播时间,极大提升火焰传播速度.实验还发现掺氢比例以及初始压力的提升均能使得微尺度火焰传播速度提升.