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.

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.

Experiment Study on the Exhaust-Gas Heat Exchanger for Small and Medium-Sized Marine Diesel Engine

This paper aims to design a special exchanger to recover the exhaust gas heat of marine diesel engines used in small and medium-sized fishing vessels,which can then be used to heat water up to 55°C–85°C for membrane desalination devices to produce fresh water.A new exhaust-gas heat exchanger of fins and tube,with a reinforced heat transfer tube section,unequal spacing fins,a mixing zone between the fin groups and four routes tube bundle,was designed.Numerical simulations were also used to provide reference information for structural design.Experiments were carried out for exhaust gas waste heat recovery from a marine diesel engine in an engine test bench utilizing the heat exchanger.The experimental results show that the difference between heat absorption by water and heat reduction of exhaust gas is less than 6.5%.After the water flow rate was adjusted,the exhaust gas waste heat recovery efficiency was higher than 70%,and the exhaust-gas heat exchanger’s outlet water temperature was 55°C–85°C at different engine loads.This means that the heat recovery from the exhaust gas of a marine diesel engine meets the requirement to drive a membrane desalination device to produce fresh water for fishers working in small and medium-sized fishing vessels.

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 and Economic Aspects and Experience from 6 Years of Operating the Technology Using the Waste Heat from the Exhaust Gases of Heat Sources and 3 Years of Operating a Heating Plant in an Autonomous, Island Regime

This article is focused on technical and economic evaluation of more than 6-years experiences of operating the Waste Heat Recovery technology—the manner and system of flue gas processing generated in the combustion process in heat & power plants, cogeneration units, etc., which burn the gaseous fuel, primarily natural gas, or methane, biogas, geothermal gas, or other gaseous mixtures containing hydrogen. The solution proposes a more effective and non-traditional use of gaseous fuel for heating, the flue gases of which are processed in order to extract additional utilisable heat, with potential elimination of CO2 from them. Deploying of the heating plant in an island regime (OFF-GRID) enables definition of the benefits brought by the 3 years of operational experience and presents visions for the future offering the possibility to utilise the support energy services at the municipal as well as regional level.

Experimental Investigation on Solution Regeneration Performance and Coefficients in Full-Open System for Heat and Water Recovery of Flue Gas

The recovery of heat and water from low-grade flue gas is of considerable importance for energy conservation and environmental preservation.While the full-open absorption heat pump shows promise as a means of achieving heat and water recovery,the lack of research on heat and mass transfer performance of open-type solution evaporation regeneration represents a significant impediment to its design and operation.This paper experimentally investigates the regeneration performance of an open-type spaying tower equipped with ceramic structured packings.Two different regeneration modes are proposed,namely ambient air receiver mode and flue gas receiver mode,to utilize air or low-grade flue gas as a driving source.The impact of different input parameters on the regeneration characteristics,including heat transfer capacity,water removal rate,thermal efficiency,and humidity effectiveness,are demonstrated.The findings indicate that the enhancement of regeneration can be achieved through the increase of solution flow rate,solution temperature,and flue gas flow rate in both regeneration modes.However,high solution concentration and flue gas humidity ratio can weaken water removal rates and reduce thermal efficiency.For the regeneration of CaCl_(2)-H_(2)O with a concentration of55%,flue gas around 200℃with a humidity ratio below 44 g/kg can successfully drive the solution regeneration process.When the solution concentration or flue gas humidity ratio continues to rise,additional energy is necessary for regeneration.Furthermore,the coupled heat and mass transfer coefficients are fitted,which can contribute to the design and optimization of the open-type regenerator.

Machine learning-based multi-objective optimization and thermal assessment of supercritical CO_(2) Rankine cycles for gas turbine waste heat recovery

Technologies for utilizing waste heat for power generation have attracted significant attention in recent years due to their potential to enhance energy efficiency and reduce greenhouse gas emissions.This research focuses on the comparative and optimization analysis of three supercritical carbon dioxide(sCO_(2))Rankine cycles(simple,cascade,and split)for gas turbine waste heat recuperation.The study begins with parametric analysis,investigating the significant effects of key variables,including turbine inlet temperature,condenser inlet temperature,and pinch point temperature,on the thermal performance of advanced sCO_(2) power cycles.To identify the most efficient cycle configuration,a multi-objective optimization approach is employed.This approach combines a Genetic Algorithm with machine learning regression models(Random Forest,XGBoost,Artificial Neural Network,Ridge Regression,and K-Nearest Neighbors)to predict cycle performance using a dataset extracted from cycle simulations.The decision-making process for determining the optimal cycle configuration is facilitated by the TOPSIS(technique for order of preference by similarity to the ideal solution)method.The study's major findings reveal that the split cycle outperforms the simple and cascade configurations in terms of power generation across various operating conditions.The optimized split cycle not only demonstrates superior power output but also exhibits enhanced net power output,heat recovery,system and exergy efficiency of 7.99 MW,76.17%,26.86%and 57.96%,respectively,making it a promising choice for waste heat recovery applications.This research has the potential to contribute to the advancement and widespread adoption of waste heat recovery in energy technologies boosting system efficiency and economic feasibility.It provides a new perspective for future research,contributing to the improvement of energy generation infrastructure.

Heat Transfer and Energy Utilization of Waste Heat Recovery Device with Different Internal Component

Steel industry is high energy-consuming industry, and its waste?heat recovery is critically?important for energy utilization. In this study, pipeline bundle is used to enhance heat transfer in?waste?heat recovery device,?and?associated gas-solid heat transfer and energy utilization performance with different pipeline arrangement, pipe diameter and shape of internal component are further analyzed. The temperatures of gas and particle in device with pipeline bundle periodically fluctuate in horizontal direction, and those in staggered system distribute more uniformly than those in paralleled system. Compared with paralleled device, exergy and waste heat utilization efficiency of staggered device have been improved, and they are both higher than?those without pipeline. As pipe diameter increases, exergy and waste heat utilization efficiency first increases and then decreases, and they reach the maxima with optimal pipe diameter.?As the width of internal component keeps constant, influence of its shape on heat transfer is very little.

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.

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.

Characteristics of gaseous product from municipal solid waste gasification with hot blast furnace slag

Possibility of combustible gas production from municipal solid waste （MSW） using hot blast furnace （BF） slag has been studied.The objective of this work is to generate combustible gas from MSW using heated BF slag.In this experiment,the thermal stability of the MSW was analyzed by thermogravimetric analysis,and effects of temperature,gasifying agent （air,N2,steam） and BF slag on the gas products were investigated at 600？900 ？C.The thermogravimetric analysis indicates that the weight loss of MSW includes four stages：evaporation of the moisture,combustion of volatile materials,burning of carbon residue and burnout of ash.The contents of the combustible gas increase with increasing temperature,and the lower calorific value （LCV） increases rapidly at 600？900 ？C.It is found that volume fraction of CO,H2 and CH4 at different atmospheres increases in the order N2〈air〈steam.It is believed that BF slag acts as the catalyst and the heat carrier,which promotes the gasification reactivity of MSW.

Transforming Waste Heat into“Renewable Heat”

Introduction:The current worldwide electric power&heat&cool production has a negative impact on the environment by emissions and enormous leaks of low-potential waste heat.Transformation of unused industrial low power heat into“renewable heat”useful to enhance the efficiency of the system is essential and actual innovation in the field of worldwide environmental protection.By introducing and defining the terminology of low-potential,“renewable”,“green heat”has created a new,parallel category of research in the energy sector.Traditional co-generation systems produce heat for space heating and hot water and generate electricity.Moving to tri-generation allows growing demand for air conditioning for homes,offices and commercial spaces such as server rooms and switchboards to be met simultaneously or on a seasonal basis.Tri-generation,or combined cooling,heat and power,is the process by which some of the heat produced by a co-generation plant is used to generate chilled water for air conditioning or refrigeration.Usually an absorption chiller is linked to the plant to provide this functionality.The technical solution is related to the new efficient manner and system of simultaneous generation of heat/cold from multiple heat sources,which has not yet been known,but in practice required.New system also enables advantageous utilization of solar power in supporting of the cooling output.The innovative system can be operated also within the existing central heating distribution systems.

水蒸气载热式锅炉烟气余热回收系统的节能量测量方法

烟气余热回收可有效降低锅炉的排烟热损失,减少燃料耗量和温室气体排放。近年来,作为一种高效的全热热回收方式,水蒸气载热式锅炉烟气余热回收系统已在实际工程中得到一定的应用,但由于其流程及能量转化关系较为复杂,人们对该系统节能量如何判定存在争议。本文在分析烟气余热回收系统及其各环节的能量平衡与转化关系基础上,提出了采用温度传感器、热计量表等常规仪表间接测量整个余热回收系统及其锅炉助燃风预热节能量的方法,并以山东临邑恒利热电厂为例给出了采用水蒸气载热式锅炉烟气余热回收前、后的测量结果。数据分析表明,对于蒸发量为176.90 t/h的锅炉,整个烟气余热回收系统的总节能量为10.86 MW,占锅炉产热量的8.46%,其中通过锅炉的进风预热加湿使锅炉加热助燃风节能1.73 MW,占余热总回收量的16%。该测量方法为水蒸气载热式锅炉烟气余热回收系统规模化应用提供了节能量在线实时监测的技术支撑。

一种智控型烟气余热深度回收装置的实践探索

为了解决大庆油田加热炉排烟温度高、生产能耗大的问题,在加热炉排烟系统增设智控型烟气余热深度回收装置,以加热炉进液为冷源,将排烟温度冷却至50℃以下,综合回收烟气的显热和潜热,达到深度回收烟气余热的目的,并对烟气降温过程中产生的冷凝水进行全部回收,从根本上解决了冷凝水排放问题。应用装置前后系统整体热效率分别为79.94%和87.47%,综合计算得到装置的节能率为8.35%,节能效果显著;此外,对于1.0 MW加热炉,年平均负荷率50%,年运行时间330 h,测算得到每年节约天然气4.58×10^(4) m^(3),折合7.4万元,具有良好的经济效益。

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.

前置暖风器电站锅炉烟气余热回收系统多参数设计与变工况运行策略

针对前置暖风器烟气余热回收系统,建立了多参数设计优化与变工况特性计算模型,开展了系统的多参数优化,并提出了运行参数控制策略。结果表明:多参数优化后系统在设计工况下的节煤率为3.67 g/(kW·h);多参数优化后的系统在变工况下虽能保持较高的节煤率,但系统的安全性受到环境温度和负荷的严重制约;采用所提出的控制策略可使系统在100%额定负荷下,安全运行的环境温度下限从24℃扩展至-3℃,显著提高了系统优化的综合效果。

湿法脱硫后烟气和浆液余热回收技术研究进展

低品位余热高效深度利用是促进燃煤电站进一步节能减排的关键之一,湿法脱硫后的低温饱和湿烟气蕴含大量潜热和水资源,大量脱硫浆液吸收烟气热量后温度升高。烟气与浆液具有巨大的余热利用和水资源回收的潜力,若直接排放烟气,直接排出浆液,不但造成资源浪费,还容易引发“白色烟羽”污染环境。本文以湿法脱硫后饱和湿烟气和脱硫浆液为研究对象,针对目前湿法脱硫技术余热回收效率低、利用难以匹配冷源等困境,总结了国内外针对脱硫后烟气水热回收和浆液余热回收技术及发展方向,研究中针对浆液余热利用仍待发展。其中,直接冷凝烟气和浆液技术和热泵技术成熟,应用广泛;溶液吸收技术能源利用率高,烟气腐蚀性低;烟气膜分离技术、浆液闪蒸、热泵技术清洁环保,回收质量高。直接冷凝烟气、浆液技术和膜分离技术需要进一步提高抗腐蚀性和转换效率;浆液闪蒸、热泵技术能耗较高,吸收式热泵技术仍需寻找高效安全环保无毒的吸收溶液。最后,探讨了目前脱硫浆液余热利用的主要方式及存在问题,回收余热主要用于供暖和电厂内部热利用,以期进一步推动湿法脱硫后烟气与浆液余热回收利用,实现燃煤电站的深度节能减排。

烷烃脱氢加热炉排烟余热深度回收协同烟压控制性能分析

炼化装置加热炉为石油炼化生产工艺中高能耗、高碳排放设备之一,但低温下烟气冷凝水会腐蚀换热设备,增设排烟余热回收换热设备还会增加烟气系统阻力,对生产工艺造成影响,降低加热炉燃烧效率。排烟余热回收利用系统的防腐、高效、低阻力及烟压控制是余热回收系统能效最大化技术难题。本文以炼化装置加热炉为对象,以烷烃脱氢加热炉为例,提出加热炉低温排烟余热深度回收协同炉膛烟压控制系统方案,采用自主研发的防腐、高效、低阻力排烟余热回收设备,建立加热炉低温排烟余热回收利用节能改造示范工程,并跟踪实测,将实测值与理论值进行对比。结果表明:该系统可将炉膛烟压控制在满足生产工艺要求范围内,控制精度达(-35±6.4)Pa;排烟温度由178.3~178.7℃降至54.3~78.7℃,系统节能率达4.75%~6.9%,烟气余热回收率达28.1%~40.4%,其中梯级换热比单级换热性能提高43.8%,(火用)效率可达52.8%~63.7%,并减少CO_(2)排放2884.5~4197.9t/a,且降低NO_(x)和SO_(2)等污染物排放,节能、减污、降碳效果显著。为炼化装置加热炉的排烟低温余热利用技术开发与应用提供了参考和示范。

硫回收装置余热锅炉铵盐结晶腐蚀机理研究

针对某公司硫回收装置余热锅炉在运行过程中出现了大范围的结晶现象、给装置带来了流道沉积堵塞和设备腐蚀泄漏等严重问题,重点研究结晶对设备的腐蚀机理。利用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分别测定了结晶样品的微观结构、元素分布和物相组成。结果表明,结晶样品的微观结构呈现平滑致密和粗糙多孔两种形态,晶粒尺寸在20~50μm;所含元素种类主要有N,O,S,Fe,C,其中余热锅炉列管内结晶底面Fe含量达到了35%,说明沉积结晶对设备有较强的腐蚀作用;主要物相组成为NH_(4)HSO_(4),(NH4)_(2)SO_(4),(NH_(4))_(3)H(SO_(4))_(2)等铵盐;制硫尾气中含有的NH3是结晶形成的根本原因。此外,对不同区域的腐蚀过程进行了详细阐述,为该装置同类问题的研究和解决提供参考。

耦合余热回收下电站锅炉尾部烟气热能高效梯级利用系统设计

针对电站锅炉尾部烟气热能利用效率较低,梯级利用数值模拟过程与全尺度数据分析过程偏差较大的问题,设计了一种耦合余热回收下的电站锅炉尾部烟气热能高效梯级利用系统。实验结果表明,系统的最佳烟气热能高效梯级节点利用情况和热能梯级置换情况整体都保持在60%以上,采用热能阶梯式温差电站后,系统整体效率提高了约22%,证明了所设计系统的使用优越性。