煤粒度对循环流化床燃烧影响分析

循环流化床燃烧技术属于一种新型的高效洁净燃烧技术,与其他燃烧方式相比,循环流化床燃烧技术具备着低污染、高效率、燃烧适应性广、灰渣能够有效利用等优点,广泛应用于循环流化床锅炉中,在保护环境、节约能源、充分利用劣质煤等方面发挥着重要作用。然而在应用循环流化床技术时,要求煤粒度符合一定的粒度要求。通过研究发现,煤粒度对循环流化床锅炉存在着较大影响,主要表现在点火启动、锅炉运行及燃烧效率、对设备磨损及底渣粒径分布等方面。本文通过对煤粒度对循环流化床燃烧影响分析,主张合理控制煤粒度,提高燃烧效率,最终为企业收获良好的经济效益。

烟气再循环对循环流化床锅炉燃烧影响的对比研究

某电厂300 MW CFB锅炉进行了烟气再循环改造。改造后,机组启动及运行中发现投入烟气再循环后,锅炉主要运行参数发生变化,进一步适应电网深度调峰要求。为分析其指标变化原因,某电厂开展了相关热态试验,本文对比分析了烟气再循环投停对锅炉主要运行参数及经济指标的影响。经性能测试试验结果对比分析,300 MW负荷下锅炉风机总电流增加260 A,底渣及飞灰可燃物含量分别增加1.2%和1.9%,机组厂用电率上涨0.85%,锅炉效率下降1.85%,为CFB锅炉深度调峰期间优化烟气再循环运行方式提供了技术参考。

进气道结构对混动发动机滚流和燃烧影响

随着电池、电机成本的进一步降低,混合动力汽车因其良好的动力性、经济性和低排放特性,将逐渐成为主流,进而推动传统内燃机向高效率、低排放方向发展。混合动力系统可使发动机运行在高效的点工况或线工况上,因此最高热效率对于混合动力发动机至关重要。常见能提高热效率的技术有:高压缩比、中冷 EGR(排气冷却再循环)、米勒循环、稀薄燃烧、涡轮增压等。这些技术的采用可能会引起缸内燃烧的不稳定、早燃甚至爆震等不利因素出现,因此需要设计更加先进的燃烧系统来组织清洁高效的燃烧。

煤粒度对循环流化床燃烧影响分析

燃烧方法是一种新的清洁高效的循环流化床燃烧方法。循环流化床过程中的燃烧技术与其他燃烧方法相比具有以下优点:污染低、效率高、燃烧调节高、灰渣利用率高。在保护环境、提高能效和优化利用劣质煤水合物方面发挥着重要作用。但是,在应用循环流化床技术时,必须对煤颗粒的尺寸提出一些要求。研究表明,煤颗粒的大小对循环流化床锅炉的分布有重大影响,主要影响锅炉的启动、运行和燃烧效率、设备磨损和粒径。从煤粉对循环流化床燃烧的影响分析出发,实现了对煤粒度的合理控制,提高了燃烧效率,最终给企业带来了经济效益。

燃烧对森林土壤物理性质的影响

自然燃烧会毁掉大量的对土壤物理性质起着积极作用的森林凋落物。另一方面,控制燃烧能烧掉的有机表层一般低于50%。美国加里福尼亚黄松林的燃烧试验表明,4次燃烧,烧掉了枯叶层的76%及粗腐殖层的23%。

W形火焰锅炉的煤粉均匀特性和风量对燃烧的影响分析

介绍了W形火焰锅炉的燃烧特点,着重分析了此类型锅炉直吹式制粉系统的风量、煤粉均匀性在不同状态下的特性及其对燃烧的影响,分别阐述了冷态、热态检验及调整的效果。最后指出要满足燃烧的要求,W形火焰锅炉的风速、煤粉调平工作必须在热态下进行。

锅炉燃烧不完全的影响因素及解决措施

对锅炉来说,如果燃烧不完全会导致锅炉效率下降,影响舰艇续航力,该文从分析锅炉的燃烧过程出发引出影响锅炉燃烧的几个因素即燃油、供油设备和空气供给等,并详细阐述这些因素,最后提出了解决燃烧不完全的措施和建议。

“燃烧的条件”实验再改进

针对“燃烧的条件”实验存在的不足,通过分析文献和探索实践,提出新的改进方案。新方案遵循教材原型实验教学意图,利用燃烧匙、集气瓶、导管、气球、橡胶塞等物品,进行改进设计。改进后的实验具有装置简约、操作简便、效果显著等优点,同时结合实际对实验进行拓展探究,提出了比表面积、闪点等对物质燃烧有影响的因素,以帮助学生提升对燃烧知识的认识。

浅谈锅炉结焦对燃烧的影响及防范措施

锅炉结焦不仅影响了锅炉的安全性,而且影响了锅炉燃料燃烧时利用率。锅炉结焦一方面不仅严重影响了人们的身体健康,另一方面也使资源不能得到最大化的利用。浪费了燃料,对环境造成了污染。当然锅炉结焦的问题的产生,包括很多方面。一方面是锅炉内部煤炭的质量;另一方面是燃烧煤炭的锅炉自身设计。若锅炉中的煤炭质量不好,会导致煤炭燃烧不完全或燃烧时有危害气体产生,进而对人体和周围的环境产生影响。这些情况在锅炉结焦的燃烧方面产生不良影响。另一方面是锅炉内部的问题,例如锅炉内部温度不均匀等。若锅炉的质量较差,即锅炉内部不能保证煤炭燃烧时的安全性和持续性,则锅炉燃烧产生的气体也将会对生态环境有害,同时严重影响人们的身体健康。锅炉结焦的原因有一部分来自相关的技术人员的技术水平和对待锅炉燃烧的态度。部分技术人员的专业水平只能解决表面问题,不能从根本问题解决,或者对于工作没有足够的责任心。导致锅炉内部的灰质不能做到及时的清理,进而使锅炉内部剩余的灰质结焦,对锅炉内部物体的燃烧产生恶劣影响。在当前社会,我国越来越注重对生态环境的保护。因此我们应坚决防止锅炉内部结焦,导致内部物体燃烧不完全产生对环境,对人体有害的气体。以下是我对于锅炉结焦燃烧的影响及锅炉结焦的防范措施的简要分析。

燃煤的储存与掺配

煤炭是国家重要能源,是火力发电企业主要成本,燃煤的管理与掺配好坏,与企业效益息息相关。通过对发电厂燃煤储存动态管理和科学掺配,满足电厂锅炉用煤需要,提高燃煤利用效率,提高锅炉热效率,减少了设备故障率,减轻了维护人员的工作量,从而达到提升企业管理水平和经济效益,确保发电企业经济、环保、安全、稳定运行。

Analysis and key control technologies to prevent spontaneous coal combustion occurring at a fully mechanized caving face with large obliquity in deep mines

In order to prevent spontaneous coal combustion occurring at a fully mechanized caving face with large obliquity in deep mines in China, we have analyzed the characteristics of spontaneous coal combustion and explain theoretically the factors affecting spontaneous coal combustion, such as rock bursts, high temperatures, high ventilation resistance, slow advancing speed and large obliquity mining. Key technologies to prevent spontaneous combustion occurring in sharply inclined seams in deep mines are pro- posed; these include pouring water, stopping leakage in upper and lower comers of the working face, choking off the goaf and cov- eting the coal. CO concentrations were controlled within two years to less than 15×10^-6 at the upper comer by applying these tech- nologies at the 1410 working face of the Huafeng coal mine. Our method has significant theoretical value and is of practical impor- tance in controlling spontaneous coal combustion occurring at a fully mechanized caving face with large obliquity in deep mines.

Distribution of bromine and iodine in thermal power plant

The bromine （Br） and iodine （I） in raw coal, bottom ash （BA） and fly ash （FA） from seven thermal power plants （TPP） digested with pyrohydrolysis were determined by using inductively coupled plasma mass spectrometry （ICP-MS）. The distribution behavior of Br and I during coal combustion were researched and the environmental effects of Br and I in BA, FA and gas phase were analyzed. The results show that both elements Br and I in combustion products from TPP are usually pre- sent in decreasing order of the distribution rate as gas phase, FA and BA. In FA and BA, the distribution rate of Br （8.11% and 1.68%, respectively） are generally lower than that of I （9.26% and 4.67%, respectively）; on the contrary, in gas phase, the former （90.2%） is higher than the latter （86.9%）. In addition, for gas phase, the percentage of Br： （2.0%-75%） in total Br is generally larger than that of I2 （1.0%-10%） in total I. The environmental effects for Br and I emitted into atmosphere from TPP may be larger than those remained and captured by both FA and BA.

Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion(Ⅰ)

In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

STUDY ON MAJOR FACTORS INFLUENCINGSPONTANEOUS COMBUSTION OF COAL

This paper theoretically analyzes major factors influencing spontaneous combustion of coal, such as molecule structure of coal, porosity, temperature, concentration of oxygen, coal thickness, velocity of face advance, and so on; and probes into how they affect the process of spontaneous combustion of coal, which is of momentous significance to predict or control self ignition of coal.

A back analysis of the temperature field in the combustion volume space during underground coal gasification

The exact shape and size of the gasification channel during underground coal gasification(UGC) are of vital importance for the safety and stability of the upper parts of the geological formation.In practice existing geological measurements are insufficient to obtain such information because the coal seam is typically deeply buried and the geological conditions are often complex.This paper introduces a cylindrical model for the gasification channel.The rock and soil masses are assumed to be homogeneous and isotropic and the effect of seepage on the temperature field was neglected.The theory of heat conduction was used to write the equation predicting the temperature field around the gasification channel.The idea of an excess temperature was introduced to solve the equations.Applying this model to UCG in the field for an influence radius,r,of 70 m gave the model parameters,u1,2,3...,of 2.4,5.5,8.7...By adjusting the radius(2,4,or 6 m) reasonable temperatures of the gasification channel were found for 4 m.The temperature distribution in the vertical direction,and the combustion volume,were also calculated.Comparison to field measurements shows that the results obtained from the proposed model are very close to practice.