Optimal dynamic dispatch of surplus gas among buffer boilers in steel plant

As valuable energy in iron-and steel-making process,by-product gas is widely used in heating and technical processes in steel plant.After being used according to the technical requirements,the surplus by-product gas is usually used for buffer boilers to produce steam.With the rapid development of energy conservation technology and energy consumption level,surplus gas in steel plant continues to get larger.Therefore,it is significant to organize surplus gas among buffer boilers.A dynamic programming model of that issue was established in this work,considering the ramp rate constraint of boilers and the influences of setting gasholders.Then a case study was done.It is shown that dynamic programming dispatch gets more steam generation and less specific gas consumption compared with current proportionate dispatch depending on nominal capacities of boilers.The ignored boiler ramp rate constraint was considered and its contribution to the result validity was pointed out.Finally,the significance of setting gasholders was studied.

锅炉管泄漏原因

某锅炉管在运行过程中发生泄漏事故。采用宏观观察、化学成分分析、金相检验、扫描电镜及能谱分析等方法分析了锅炉管泄漏原因。结果表明:管道内存在腐蚀性介质,在工作应力以及热应力的共同作用下,管道内壁发生了应力腐蚀开裂,裂纹不断扩展并穿透壁厚,最终导致锅炉管发生泄漏事故。

锅炉扁钢用免退火12Cr1MoV盘条控轧控冷工艺优化

为开发免球化退火扁钢用12Cr1MoV热轧盘条,基于形变诱导相变机理,采用830℃终轧温度和800℃的吐丝温度。通过抑制形变奥氏体晶粒回复和再结晶过程增加形变储能,促进奥氏体分解为铁素体和珠光体组织。同时配合轧后风冷辊道速度调节,实现分段控制冷却,延长盘条在630~750℃区间停留时间,可完全消除盘条中马氏体和贝氏体组织。试验结果为:热轧盘条抗拉强度从576 MPa降至520 MPa,断面收缩率从66%提高至74%,淬火组织的消除使盘条变形能力明显优化,避免少量或极少量马氏体组织无法协同变形而产生的心部孔洞或拉拔断裂,经用户多规格批量使用,未发生塑性开裂问题。

GB/T 5310-2023《高压锅炉用无缝钢管》国家标准概述

简要介绍了《高压锅炉用无缝钢管》(GB/T 5310—2023)修订的背景,重点解析修改的主要技术内容,对比分析国内外相关标准主要技术指标,并提出实施新版标准的建议,对企业执行标准具有指导意义。分析认为:新版GB/T 5310在标准的适用范围、钢管的尺寸精度、钢的化学成分、钢管的力学性能均与国外先进标准相当;在钢管的检验项目及指标要求方面,如无损检测、低倍、非金属夹杂物、显微组织、晶粒度和脱碳层要求等,新版GB/T 5310比国外先进标准规定项目多,部分指标要求严。

T91+TP347H异种钢焊接接头失效分析

某电厂超临界锅炉运行中发现高温再热器出口T91/TP347H异种钢焊接接头发生断裂致使锅炉泄漏。对失效焊接接头进行宏观形貌观察、化学成分分析、金相检验、硬度测试等一系列检验,结合该锅炉的运行情况和历史故障情况,综合分析该锅炉异种钢焊接接头的失效原因。结果显示,焊缝成形差、焊接质量不合格是导致出现接头开裂的直接原因;异种钢接头本身化学成分差异大,性能不均匀,在长期的高温和应力作用下发生元素迁移,造成交界面性能下降,这是焊接接头出现开裂的根本原因;机组的深度调峰、频繁启停调峰则进一步加速了裂纹的产生。经过失效原因分析,并借鉴异种钢焊接接头的管理标准及实践经验,建议加强焊接质量控制和优化金属监督策略,提高无损检测的抽样率,并注意控制机组调峰速率。可为同类型电厂异种钢焊接接头管理提供参考。

“双碳”目标下钢铁企业煤气发电技术发展及影响

钢铁企业煤气发电技术有助于我国钢铁行业实现“双碳”目标以及应对欧盟碳边境调节机制(CBAM)贸易壁垒。通过研究钢铁企业煤气锅炉发电技术发展及其对钢铁企业碳排放的影响,年产粗钢1 000万t的钢铁企业采用新型高效超超临界参数煤气锅炉发电技术可减少二氧化碳年排放量188.57万t,较采用高温超高压煤气发电技术的相对减碳量增幅达15.71%。通过基于欧盟碳边境调节机制规则的计算分析,采用新型超超临界参数煤气锅炉发电技术的钢企钢材单位出口成本较我国钢铁行业总体水平降低约94.2元/t,相对降幅达10.9%。

高压锅炉管用钢12Cr1MoVG的开发生产

凌钢通过采用冶炼—脱氧合金化(合金烘烤)—LF精炼—RH真空—8号铸机—堆冷—轧制—收集—入坑缓冷生产工艺成功研发了高压锅炉管用钢。根据其技术要求设计合理的生产工艺过程,针对关键技术加强过程和关键参数的控制,并对生产的产品的化学成分、非金属夹杂物、晶粒度、气体含量等技术指标进行统计分析。结果显示,钢材的各项性能指标完全满足用户要求,产品组织均匀,纯净度高,性能控制稳定。

垃圾焚烧余热炉的安装施工工艺研究

结合具体的工程案例,对生活垃圾处理厂的余热锅炉的施工进行分析,从锅炉钢架、受热面、汽包等方面,探讨具体的施工工艺,希望能够为类似工程的安装施工提供参考和借鉴。

精密铸造锅炉管件用耐热奥氏体钢的研究

为了优化耐热奥氏体钢在锅炉管件精密铸造中的工艺,选取典型焊接接头进行分析,预热温度≥5℃,电压13~14V,焊层数3层,电流190~200 A,层间温度50~230℃。结果显示,600~1200℃温度环境下,AFA25-15为单相奥氏体基体,析出相为NiAl、σ相、M_(23)C_(6)、MC碳化物。通过适当冷变形处理之后,强度明显提升,AFA-50%与AFA-20%抗拉强度均有所降低,断后伸长率变动差异表现不明显。材料氧化腐蚀程度与温度呈正比关系,S31042材料抗氧化腐蚀能力最强,S31035与C-HRA-5材料抗氧化腐蚀能力基本相当。通过本文的研究与探讨,有利于改善锅炉管件用耐热奥氏体钢的综合性能,提升拉伸性能。

长期服役锅炉末级再热器管泄漏分析

某电厂600 MW亚临界机组累计运行14万h后,锅炉末级再热器管发生泄漏。通过宏观观察、金相分析、扫描式电子显微镜(SEM)观察、能谱分析、X射线衍射(XRD)分析、硬度测试、拉伸性能测试等方式,对发生泄漏的末级再热器12Cr1MoV钢管段进行分析。结果表明:发生泄漏的进汽侧12Cr1MoV钢管段已发生明显的组织老化,球化等级为4级,布氏硬度降低至103HBW,屈服强度低于标准值。机组长期运行过程中再热器管内壁的氧化皮发生脱落,使U形弯管的下弯头部位堵塞,从而导致进汽侧直管段发生严重超温。12Cr1MoV材质发生组织老化和性能下降,管内壁氧化皮脱落严重导致壁厚减薄,从而引起爆管泄漏。

GB/T 13296《锅炉、热交换器用不锈钢无缝钢管》新旧标准对比分析与研究

叙述了锅炉、热交换器用不锈钢无缝钢管产品迎合了当代先进应用领域发展的前瞻性需求,为了更好的理解和执行GB/T 13296-2023《锅炉、热交换器用不锈钢无缝钢管》标准,从适用范围、规范性引用文件、技术要求、新旧标准水平对比以及与国外标准的对比等方面阐述了新旧标准之间的差异和分析结论,针对性的对关键先进、领先指标内容进行解读,对标准采纳和实施过程中的具体执行给出可行性的实施建议。

锅炉受热面异种钢焊缝相控阵超声与射线检测分析

通过相控阵超声检测与射线检测对某锅炉受热面异种钢焊接接头进行检测对比分析及验证试验,结果表明相控阵超声检测结果更准确。因此,建议在进行电站锅炉受热面异种钢焊接焊缝的无损检测时,可采用相控阵超声检测替代射线检测。

锅炉高温再热器长时服役TP310HCbN钢管失效分析

针对某660 MW超超临界机组服役4.6万h后的锅炉高温再热器,通过金相检测、扫描电镜、拉伸试验和冲击试验等方法对泄漏的TP310HCbN钢管的组织形貌和力学性能进行研究。结果表明:长时高温服役使TP310HCbN钢管的金相组织老化至3~4级,晶界析出大量碳化物,管材严重脆化,导致其韧性储备不足,受外力撞击后外壁表面形成大量微裂纹,随着服役时间的延长,管样裂纹逐渐扩展并最终导致爆管泄漏。

Hot-corrosion behavior of Cr_2O_3–CNT-coated ASTM-SA213-T22 steel in a molten salt environment at 700°C

The present work investigates the hot-corrosion behavior of carbon nanotube(CNT)-reinforced chromium oxide coatings on boiler steel in a molten salt(Na_2SO_4–60 wt%V_2O_5) environment at 700°C under cyclic conditions. The coatings were deposited via the high-velocity oxygen fuel process. The uncoated and coated steel samples were subjected to hot corrosion in a silicon tube furnace at 700°C for 50 cycles. The kinetics of the corrosion behavior was analyzed through mass-gain measurements after each cycle. The corrosion products were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis techniques. The results revealed that uncoated steel suffered spallation of scale because of the formation of nonprotective Fe_2O_3 scale. The coated steel samples exhibited lower mass gains with better adhesiveness of oxide scale with the steel alloy until the end of exposure. The CNT-reinforced coatings were concluded to provide better corrosion resistance in the hot-corrosion environment because of the uniform dispersion of CNTs in the coating matrix and the formation of protective chromium oxides in the scale.

Review of research developments of 12Cr1MoVG heat resistant steel in China

In this paper, we review the evolution of 12CrlMoV steel standards at home and abroad, analyze the effects of various elements and determine their optimal contents in steel. The influence of heat treatment and microstructure on the creep strength of 12CrlMoV steel is investigated. Statistical results from conventional mechanical properties, ductile-brittle transition temperature, high temperature oxidation resistance, aging, instant high temperature properties, and creep are introduced. The results show that the chemical composition and heat treatment process of 12CrlMoVG steel identified in the GB 5310 - 2008 standard is appropriate, resulting in a steel with higher creep strength and good comprehensive properties.

Effect of Revolution on Inhomogeneous Deformation of IF Steel in High Pressure Torsion

The effect of revolution on inhomogeneous plastic deformation of HPT processed IF steel was investigated using experimental and simulation approaches. The results indicate that the degree of inhomogeneous plastic deformation increases as the revolutions increase along the radial direction on the transversal plane of disks. In addition, the hardness and the microstructure distributions verify the trend that the effective strain of the HPT processed disks at the early torsion stage is gradually deformed from the edge to the center with the revolutions increases.

Inhomogeneous Hardness Distribution of High Pressure Torsion Processed IF Steel Disks

The inhomogeneous hardness distribution of high pressure torsion (HPT) processed IF steel disks along different directions is investigated. The results indicated that there exists inhomogeneous distribution in HPT processed IF steel disks, giving lower hardness in the center and higher hardness in the edge regions. However, on the axisymmetrical section testing plane of the disks’ thickness direction, there is a soft zone near the surface of disks. Further results from radius testing plane of different depths from the surface of HPT processed disks show that the inhomogeneity rules of hardness distribution on the radius direction are similar to that on the thickness direction. Compared with the initial state, different stages of HPT (compression and compression + torsion) can both remarkably increase the hardness of IF steel disks. Microstructure investigation results can give a well support to verify the rules of hardness distribution, showing hardly no change of grains in center and sever plastic deformation in edge. The inhomogeneous distribution of stress and strain with the huge friction between anvil and disks in the process of HPT play an important role of hardness and microstructure distribution.

超超临界锅炉末级过热器异种钢焊接接头断裂原因分析与预防

对某电厂开裂的超超临界锅炉末级过热器F91/TP310HNbN异种钢焊接接头进行分析,包括宏观形貌检查、几何尺寸测量、金相组织检验、扫描电镜断口形貌分析和维氏硬度试验。结果表明:异种钢焊接接头开裂是焊缝的化学成分、组织、力学性能和物理性能与不锈钢侧母材差异较小,而与F91侧母材差异较大,导致F91侧焊缝熔合线附近成为整个接头的薄弱环节,再加上多种应力作用共同造成的。预防异种钢焊接接头早期失效应选用更为合适的焊材进行焊接,并在机组停机时加强金属监督检验。

Investigation and Analysis of High Temperature Corrosion and Degradation of Marine Boiler Combustion Swirler

现在的纸调查了并且分析了 swirler 材料由在 30 MW 水兵锅炉为一年的时期受到服务的低碳钢组成。由于在结合的炉子的高温度的存在，腐蚀剂水兵环境 swirler 材料显示出加速的降级和材料消耗量。调查进与交替的材料或涂层生产存在 swirler 的可行性有热障碍涂层的 swirler 材料被承担。基于他们的性质和表演， SS 304 和 SS 316 为 swirler 作为代替材料被建议。有在提高的温度在他们的表演为任何改进观察的热障碍涂层也是的一种形式的存在 swirlers 测试了的涂层的另外的选择。钨铬钴合金，它是一个 Ni 公司基于涂层，在 MS 样品上被执行，一样暴露于上面提及的一样的温度。可得到的选择的表演关于材料的谷物结构被评估，在提高的温度的材料和恶化的坚硬价值。调查证明象 SS 304， SS 316 和钨铬钴合金涂层一样的建议材料 / 涂层表明 SS 316 是适合高温度申请的材料最好。

超超临界锅炉烟气环境中S31042、S31035、C-HRA-5奥氏体耐热钢热腐蚀行为研究

为研究超超临界锅炉过热器候选材料在高温烟气环境下的腐蚀行为,开展了3种奥氏体耐热钢S31042、S31035、C-HRA-5暴露于实验室模拟燃煤锅炉烟气中的热腐蚀试验。试验包括650、675、700、725℃4个温度,试样表面有无涂覆、涂覆真实煤灰、涂覆腐蚀性模拟煤灰3种工况,试验时长为500 h。通过试验研究获得了3种材料的腐蚀动力学曲线,采用XRD、SEM和EDS对材料的腐蚀行为进行了分析,并对比了3种材料的耐腐蚀性能。结果表明:在无涂覆和涂覆真实煤灰工况下,3种材料均表现出优秀的抗氧化和腐蚀能力;在涂覆腐蚀性模拟煤灰工况下,材料腐蚀加剧,腐蚀产物分层;不同表面工况下温度的影响有所不同;S31042材料的耐腐蚀性能最强,S31035和C-HRA-5材料相当。