Study on Curing Effect and the Waste Heat Recovering Equipment Design of Flue Gas of Bulk Curing Barn

In order to realize tobacco curing with energy saving and emission reduc- ing and lower cost, the waste heat recovering equipment was designed and built on blowing-upward type bulk curing barn. The comparative experiment of tobacco leaf curing was conducted between a bulk curing barn with waste heat of flue gas and conventional bulk curing barn. The results showed that the effect of saving coal in bulk curing barn with waste heat of flue gas was obvious than the contrast. The coal consumption quantity was 1.531 kg per kg of dry tobacco leaf. The saving coal in bulk curing barn with use waste heat of flue gas was 0.181 kg per kg of dry tobacco leaf than the contrast and saving coal rate was 10.57%. The electricity consumption quantity was 0.593 kWh per kg of dry tobacco leaf. The saving elec- tricity quantity in bulk curing barn with use waste heat of flue gas was 0.022 kWh/kg and the saving electricity rate was 3.58% than the contrast. The saving curing cost was 0.158 yuan per kg of dry tobacco leaf and saving cost rate 9.09% in bulk cur- ing barn with use waste heat of flue gas than the contrast. The appearance quality, grade structure and primary chemical composition had no significant difference be- tween bulk curing barn with use waste heat of flue gas and the contrast.

A Compound Cycle for Power Generation by Utilizing Residual Heat of Flue Gas in Electric Steelmaking Process

Electric furnace short process steelmaking is one of the most important steelmaking methods in the world today, and the waste heat recovery potential of electric furnace flue gas is huge.?The research on the recovery of electric furnace flue gas waste heat is of great significance. In order to make better use of this part of the heat,?in this paper, a compound cycle of nitrogen Brayton cycle as a first-order cycle and toluene transcritical Rankine cycle as a second-order cycle is proposed to recover waste heat from furnace flue gas in steelmaking process for power generation. A mathematical model was established with the net output power as the objective function and the initial expansion pressure, the final expansion pressure, the initial expansion temperature and the initial pressure of the second cycle as the independent variables. The effect of multivariate on the net output power of the waste heat power generation cycle is studied, and then, the optimal parameters of the compound cycle are determined. The results show that under the general electric furnace steelmaking process, the power generation efficiency of this new cycle can be increased by 21.02% compared with the conventional cycle.

Technical Measures and Selections for Reducing Flue Gas Heat Loss of Large Coal-Fired Boilers

The main technologies for reducing flue gas heat loss of pulverized coal-fired boilers are introduced, and the suitability of these technologies for boiler operation and the principles for selection of these technologies are explored. The main conclusions are： 1） the non-equilibrium control over flue gas flow rates at the inlet of the air heater and the reversal rotation of the air heater rotator should be popularized as regular technologies in large boilers; 2） increasing the area of the air heater to reduce the flue gas heat loss in pulverized coal-fired boilers should be the top option and increasing the area of the economizer be the next choice; 3） low- pressure economizer technology could save energy under special conditions and should be compared with the technology of increasing economizer area in terms of technical economics when the latter is feasible; 4） the hot primary air heater is only suitable to the pnlvefizing system with a large amount of cold air mixed.

Comprehensive Energy-Saving Technology for RTO Flue Gas Waste Heat Utilization

In the automobile painting workshop,the oven will discharge harmful exhaust gas,the exhaust gas can be reused through the TNV system,the natural gas can meet the emission standard to the atmosphere after burning,and the high temperature gas discharged TNV the system can carry considerable heat.Utilization can effectively improve the economic benefits of the factory.At present,the more mature scheme is to heat the high temperature exhaust gas through the heat exchanger,which can reduce the steam consumption of the factory.Based on the analysis of the comprehensive energy saving content of waste heat utilization of RTO flue gas,this paper hopes to provide some reference and reference for readers.

Utilization and recycling of low-temperature waste heat of stainless steel continuous annealing furnace

Stainless steel continuous annealing furnace is mainly used for heat treatment of hot-rolled strip steel.The combustion air will be enabled to heat to 520℃by waste heat recovery system,but the discharge temperature is still up to about 300℃.Owing to with development of global emphasis on energy conservation energy saving and discharge reduction,it's significant to lower the discharge temperature to below 200℃, for the sake of achieving rational use of waste heat resource.Through the analysis of the existing heat recovery system by this study,it is proved that mixing low temperature with flue gas in high temperature standard will increase the capacity of the flue gas and deteriorate the quality of remaining heat resource.In stead of that,increasing the combustion air temperature to 600℃on the basis of stability temperature for the prerequisite of recuperator design,and giving priority to reducing fuel consumption are the better way.The recovery and recycle of low temperature gas are also be introduced.It is demonstrated by the way of setting a secondary recuperator at the exit of the primary recuperator,and using low temperature flue gas to heat the air used for drying the strip steel,the exhuast temperature of flue gas can be reduced to lower than 200℃.At the same time,the steam required for heating air is saved,the energy reserve as high as 2 300 t of standard coal per year.

Preparation of gangue ceramsite by sintering pot test and potential analysis of waste heat recovery from flue gas

Preparation of ceramsite from solid waste based on the sintering process is a new technology and had a high efficiency in improving producing capability, decreasing consumption of liquefied petroleum gas (LPG), and recovering waste heat of flue gas. An experiment sintering gangue ceramsite was conducted in a 25 kg scale sintering pot with a 100 cm height. The combustion characteristics, phase transformation, and the release profile of SO_(2)^(*) (SO and/or SO_(2)) and NO_(x)^(*) (N_(2)O, NO, and/or NO_(2)) of gangue ceramsite during the sintering process were studied by X-ray diffraction analysis, X-ray fluorescence spectrometry, thermogravimetry–differential thermogravimetry–differential scanning calorimetry, and measurement of physical properties of ceramsite and gas components of flue gas. The results showed that the gangue ceramsite had excellent properties, and its compressive strength and water absorption were 8.2–9.6 MPa and 8.9%–9.8%, respectively, far exceeding the requirement of standard (GB/T 17431.1–2010). The ignition temperature of gangue ceramsite was 443 ℃, and the ignition loss was 14.60 mass% at 1000 ℃. Kaolinite and calcite disappeared at 600 and 800 ℃, respectively. Albite disappeared and mullite formed at 1000 ℃. Two peaks of SO_(2)^(*) emissions emerged in the range of 311–346 mg m^(-3) near 500 ℃ of upper layer ceramsite and 420–489 mg m^(-3) near 1000 ℃ of lower layer ceramsite, respectively. NO_(x)^(*) emissions peak emerged in the range of 227–258 mg m^(-3) near 550 ℃ of the upper layer ceramsite, which was related to the oxidation of sulfide and the combustion of LPG. Gangue is a direct heat source for sintering of ceramsite as well. During sintering process, the heat of flue gas above and below 400 ℃ accounts for 55.9% and 30.0% of the all-output heat, respectively, and was potentially used for producing waste-heat steam or electricity as by-products and drying raw materials during its own initial sintering process, which can realize combined mass and heat utilization for the gangue and further reduce the cost of sintered gangue ceramsite.

Waste heat recovery and denitrification of flue gases from gas-fired boilers

A waste heat recovery and denitrification system was developed for improving energy conservation and emissions control especially for control of PM2.5 particles and haze. The system uses enhanced heat and mass transfer techniques in a packed heat exchange tower with self-rotation and zero-pressure spraying, low temperature NO oxidation by ozone, and neutralization with an alkali solution. Operating data in a test project gave NOx in the exhaust flue gas of less than 30 mg/Nm3 with an ozone addition rate of 8 kg/h and spray water p H of 7.5–8, an average heat recovery of 3 MW, and an average heat supply of 7.2 MW.

青浦污泥干化焚烧项目设计运行分析

青浦区污泥干化焚烧项目Ⅰ期工程设计处理规模为300 t/d(含水率为80%),处理青浦区的10座污水处理厂的脱水污泥。项目核心工艺采用“薄层干化+鼓泡式流化床”干化焚烧技术,设2条生产线,设置余热锅炉回收热量生产污泥干化所需的蒸汽,配套“炉内脱硫+选择性非催化还原(SNCR)脱硝+静电除尘+小苏打干法脱酸+活性炭喷射+布袋除尘+湿式脱酸+烟气再热”组合烟气净化系统;臭气按源头有效封闭、分区分类收集、分质处理和末端组合处理的原则进行,系统产生的混合废水与脱酸废水进行分类收集、分质处理。该项目克服了类似“孤岛”建设污泥项目的困难,整体运行稳定、环保达标,对类似项目具有一定的参考价值。

关于涂装高温烟气余热再利用的研究

通过余热回用器对涂装高温烟气余热进行回收再利用,优化互利互通各个热源系统,综合利用各供热系统并合理启停热源,实现能源利用效率最大化,达到增效降本、节能减排、绿色环保的目的。

Experimental study of the flow and heat transfer of a gas–water mixture through a packed channel

Waste heat recovery from the flue gas of gasfired boilers was studied experimentally by measuring the flow and heat transfer of air and water through six kinds of packing with saturated humid air as the simulated flue gas.The experiments measured the effects of inlet air temperature, inlet air velocity and circulating water flow rate on the flow and heat transfer. The results show that higher inlet air temperatures and lower inlet air velocities lower the flow resistance and increase the heat transfer coefficient. The stainless steel packing had better surface wettability and larger thermal conductivity than the plastic packing, which enhanced the heat transfer between the water and the saturated moist air. When both the flow resistance reduction and the heat transfer enhancement were considered, the experimental results gave an optimal packing-specific surface area. A packed heat exchanger tower was designed for waste heat recovery from the flue gas of gas-fired boilers based on the experimental results which had better flow and heat transfer characteristics with lower pump and fan power consumption, more stable system operation and less thermal fluctuations compared with a non-packed heat transfer system with atomized water.

密集烤房烟气余热回收系统的设计与应用

对烟叶烘烤过程中产生的烟气余热进行回收利用,可实现节能减排、降低成本的目的。在密集烤房上搭建烟气余热回收系统,并与未采用烟气余热回收的密集烤房进行对照试验。试验结果表明,该系统节煤效果明显,平均每千克干烟叶的耗煤量为1.015 kg,比对照烤房节省0.362 kg,节煤率达到26.29%,烘烤成本降低0.33元/kg,节本率达到19.88%。此外,该系统烤后烟叶的外观质量、等级结构以及烟叶均价与对照密集烤房相比略有提高,不影响烟叶品质。

锅炉烟气余热用于木材干燥的节能改造

针对广东某胶合板企业2台蒸汽锅炉排烟温度高,不能根据工序用热需求实现能源梯级利用的问题,提出了锅炉烟气余热利用方案。根据干燥窑干燥木材的特点,将蒸汽锅炉的烟气引入干燥窑内的换热器用于干燥木材,每年通过回收利用的锅炉烟气余热折合标煤达439t。

高温空气燃烧技术的开发应用、技术优势及其展望

高温空气燃烧技术和高温空气气化技术是当前世界节能与环保领域中的两大新技术,二者均采用高于燃料着火点温度的高温空气作氧化剂或气化剂。介绍了利用蓄热式高温烟气余热回收装置和专门的高温空气发生器产生高温空气的方法,前者主要用于高温空气燃烧技术,后者主要用于高温空气气化技术。概括了高温空气燃烧技术和高温空气气化技术的应用状况,总结了其技术优势,并指出高温空气燃烧技术和高温空气气化技术符合中国国情,具有巨大的开发潜力和广阔的市场前景。

焦化行业余热回收与利用技术

介绍了焦化行业的红焦显热、荒煤气显热和烟道气余热回收利用技术，重点介绍已成功运用的偏心型径向热管在焦炉烟道气余热回收技术，具有换热效率高、环境适用性好，设备制造简单、投资低的特点，为焦化行业烟道气的余热回收利用提供一种技术参考。

面向污染物减排的烧结烟气循环研究与应用进展

对比了已有的5种典型烧结烟气循环工艺特点与应用情况,介绍了烧结烟气循环工艺的研究进展,研究了宝钢开发的BSFGR工艺对烧结烟气中O2、CO、SO2、NOX等成分排放规律的影响。结果表明,当循环烟气中O2含量从21%降至18%时,烧结烟气中O2、SO2、NOX含量均有所降低,CO含量升高,烧结烟气总排放量及各污染物排放量降低,节能减排效果显著。

烟气余热回收利用的可行性研究

烟气余热回收装置是一套用烟气热量加热吸热介质的装置。从投资、运行等各方面,针对设置烟气换热器的工程,分别阐述其有利及不利因素,并进行比较,从而论证安装烟气余热换热器具有很大的社会效益和经济效益。

海上油田透平烟气余热循环利用技术

为了解决海上油田透平烟气余热回收和含聚原油脱水加热的问题,采用透平烟气余热循环利用技术对透平高温烟气余热进行循环利用:利用热管蒸汽发生器将透平高温烟气余热与水进行热交换,产生低压饱和蒸汽;再利用相变掺热器将高温低压饱和蒸汽直接掺混加热含聚原油,使含聚原油达到脱水温度要求。该技术在SZ36-1油田进行示范应用,取得良好的效果,每年节约标准煤8060.5t,减少CO2排放量20150t。采用蒸汽直接掺混加热含聚原油,替代传统的管壳式换热器加热方式,避免了结垢和结焦严重问题的出现,换热效率提高20%~30%。

罐式炉煅烧烟气系统漏风分析与测试

煅烧烟气温度高,通常可达850~950℃,发热量可达4186~8373 kJ/m^(3),具有较高的余热回用价值,既可以用于余热锅炉产蒸汽并发电,也可以用于导热油炉加热热媒。然而在国内某些炭素企业的正常生产中,罐式炉煅烧烟气系统普遍存在漏风问题,情况严重时会造成烟气热量较大损失,为了解决上述问题,提出了一套煅烧烟气系统漏风测试与分析方法,并对某炭素厂的漏风问题进行了分析检测及优化,使得该厂煅烧烟气进入余热用户时的温度从537℃提升至820℃,余热锅炉发电量提高30%以上,较好的改善了该煅烧烟气系统的漏风问题,提高了余热利用情况。

燃气锅炉烟气余热深度回收利用的分析研究

通过常规烟气板式换热器可回收部分烟气余热,利用烟气板式换热器配套吸收式热泵机组进行烟气余热深度回收,可提高天然气能源综合利用率10%以上,节能减排的潜力巨大。

焦炉烟道气余热回收利用

通过分析烟气成分、改造原有烟道系统,采用热管+水管组合式余热锅炉,具体热力流程为热管省煤器+水管蒸发器,进行焦炉烟道气余热回收利用,减少了温室气体和酸性气体的排放,年产生蒸汽约9.6万t,收益约1 152万元,每年节约标煤约9 300 t。