型煤燃烧过程中石灰石固硫的试验研究（Ⅱ）

采用石灰石作固硫剂，考察其加入量和空气流量对北宿型煤固硫的影响，研究了固硫型煤矿析出特性和石灰石对不同煤的固硫能力。研究表明：石灰石的最佳固硫温度为８００℃、Ｃａ／Ｓ＝２：１；石灰石中所含的杂质对低温固硫有利，煤中所含钙基组分对固硫有利，石灰石对低灰熔点煤高温固硫不利。     

流化床反应器石灰石固硫特性研究

采集了兖矿地区华聚能源各电厂附近的6种石灰石,在流化床反应器中对其进行固硫实验,研究探讨了石灰石品种、粒径及脱硫温度对石灰石固硫性能的影响.实验结果表明,兖矿地区石灰石粒径小于1.5 mm时,最佳脱硫温度在900℃左右.当粒径小于0.5 mm时,石灰石的钙利用率最高可达43.86%,并且钙利用率对温度的敏感度较高,不同...     

型煤燃烧过程中石灰石固硫的试验研究（Ⅰ）：CaCO3,Na2CO3和K2C …

以高有机硫北宿烟煤为研究对象,在对石灰石中各组分进行固硫试验的基础上,对固硫能力较强的ＣａＣＯ３,Ｎａ２ＣＯ３和Ｋ２ＣＯ３在不同温度,不同固硫剂用量条件下进行了固硫试验研究,并利用改进的自动测硫仪对ＣａＣＯ３,ＮａＣＯ３和Ｋ２ＣＯ３作固硫剂时固硫型煤的硫析出特性进行了研究。     

可燃固废复合燃料的固硫固氯效果

以可燃垃圾、污水污泥和煤粉为原料,添加园林残余、固硫剂等按L16(45)正交表配料,采用机械成型设备制备固废复合燃料,研究燃料组分对固硫固氯效果的影响。固硫率、固氯率实验数据的极差、方差分析结果显示:CaO添加量对固硫率、固氯率的影响最显著;MnO2添加量对固氯率的影响仅次于CaO添加量,但对固硫率没有影响。运用ForStat 2.0统计软件建立了固硫率、固氯率指标的预测方程,置信度大于95%。应用综合评分法筛选出最佳固硫固氯效果的燃料制备配方为:A2B3C2D3,即垃圾、污泥、煤粉以2∶1∶1比例混合,园林残余为10%,助燃剂MnO2添加量为0.17%,固硫剂CaO添加1.2%时所制备的燃料,燃烧中固硫率可达74.55%,固氯率可达77.35%。     

循环流化床燃煤固硫灰改良云南红粘土

为因地制宜寻求适合固硫灰大掺量利用的新途径,解决固硫灰滞销的问题,提高固硫灰的综合利用率,利用固硫灰具有游离氧化钙含量高、火山灰特性、自硬性的特点,将其掺入红粘土进行土质改良,开展土工实验,以满足高速路基填筑材料技术要求为指标,确定适宜的固硫灰掺入量。结果表明:在红粘土中掺入适量固硫灰,能够有效降低塑性指数、增强压实性、提高承载比,固硫灰掺入量为30%以内,CBR可提高至5%以上,符合路床土最小强度要求;当固硫灰掺入量为10%~20%时,CBR可提高至15%以上,符合高速公路路床土最小强度要求。在红粘土中掺入适量固硫灰,能够有效改良红粘土,当固硫灰掺入量为10%~20%时,改良红粘土用作高速公路路床土在技术上是可行的。     

复合固硫剂对型煤固硫的影响研究

固硫型煤作为煤燃烧中脱硫的一种重要方法,在燃煤SO2的减排方面起着重要的作用。为了考察固硫剂和固硫添加剂对型煤固硫及其对型煤燃烧释放SO2的规律的影响,对利用氧化镁和氧化钙为固硫剂,以煤矸石和粉煤灰为固硫添加剂进行了研究,同时通过XRD和SEM表征,进一步探讨了固硫剂及添加剂的固硫作用和机理。研究结果表明：(1)CaO...     

MnO2对煤粉中CaO固硫效率影响机理

采用热力学计算和实验方法对钙硫比n（CaO）/n（S）=2.0条件下不同钙基固硫剂的固硫效果进行了比较,发现：CaO的固硫效率最高。以CaO为固硫剂,研究了添加剂MnO2对CaO固硫效果的影响。结果表明,加入MnO2可以提高CaO的固硫效率,且其含量为1%时对CaO固硫的促进效果最佳。这是因为煤粉燃烧过程中MnO2将逐级分解,分解产物依次为Mn2O3和Mn3O4,锰的氧化物一方面可以催化CaO的固硫反应,另一方面,Mn3O4本身也参与到固硫反应之中,生成MnSO4,从而促进钙基固硫剂的固硫效果。     

固硫灰路面基层材料的性能

以固硫灰作为路面基层材料,研究了固硫灰原灰和经预处理固硫灰路面基层材料的最佳含水量、最大干密度、体积安定性、膨胀率和强度等性能。同时,通过重金属浸出实验评估了固硫灰对土壤环境的影响。结果表明,经预处理固硫灰路面基层材料体积安定性好,膨胀率低,性能良好;此外,固硫灰重金属浸出率低,符合环保要求。     

利用铁矾渣制备轻质固硫陶粒

铁矾渣是锂电回收过程黄铁矾法除铁产生的废渣,高温条件下易分解产生二氧化硫。通过在铁矾渣中添加固硫剂制备固硫陶粒是实现铁矾渣合理利用的有效途径。通过计算高温环境下不同氧化物吉布斯自由能,并结合固硫剂铁矾渣混合焙烧实验,确定固硫效果较优的氧化钙作为固硫陶粒的固硫剂;同时,考察固硫剂掺量对固硫陶粒的固硫效果及性能的影响。结果表明,随着固硫剂掺量增加固硫率上升,固硫陶粒的吸水率和抗压强度先增加后减少,堆积密度和表观密度先减少后增加。当Ca/S 比为 2.35时,固硫陶粒的固硫率达到最高48.8%,吸水率为3.89%,抗压强度为0.79 MPa,表观密度和堆积密度分别为0.72 g·cm^-3和0.51 g·cm^-3。通过XRD和TG-DSC-FTIR分析固硫机理,发现硫酸盐通过与固硫剂相互作用形成了分解温度更高的CaSO₄和K₂SO₄。固硫陶粒的毒性浸出实验结果符合国家标准。本研究结果可为铁矾渣的高值环保利用的相关研究提供参考。     

贝壳粉型煤固硫剂固硫的实验及机理研究

以贝壳粉作为型煤固硫剂,用正交实验的方法研究了影响贝壳粉固硫率的主要影响因素,在高温(1 150℃)时固硫效率达到56.6%,比CaCO3的固硫率提高40%以上,具有较好的高温固硫性。分析得知,贝壳的主要成分为CaCO3,其含钙量在40%左右,贝壳中又含有较高的Na等碱金属元素以及Fe,Al和Si等。用X射线粉末衍射法分析了高温(1 150℃)型煤样生成的灰渣,分析了贝壳粉作为型煤固硫剂在高温下具有较高固硫率的机理。发现CaAlSi2O8为主的复合晶体在高温下包裹在CaSO4的表面,抑制了CaSO4的热分解从而有效地提高了固硫率。     

基于正交实验的颗粒移动床烟气脱硫工艺参数优化

石灰石颗粒移动床脱硫工艺参数是影响脱硫效率和操作压降变化的重要因素,考虑到工艺参数对脱硫过程的影响,基于正交实验方法,通过直观分析和方差分析得到喷淋密度、空床气速、SO2浓度、烟气温度和床层下移速度对脱硫效率影响程度的主次顺序和脱硫效率与各因素之间的关系,并且分析了各因素对脱硫效率的影响规律。研究发现,各因素对脱硫效率的影响程度依次是空床气速>喷淋密度>SO2浓度>烟气温度>床层下移速度。喷淋密度对脱硫效率的影响高度显著,呈正相关;空床气速对脱硫效率的影响高度显著,呈负相关;SO2浓度和烟气温度对脱硫效率有影响但不显著,呈负相关。床层下移速度与脱硫效率呈正相关。     

生石灰孔结构对高温脱硫性能的影响

喷钙脱硫工艺的炉内脱硫率 ,不仅受工艺参数的影响 ,还与石灰石分解生成的新生CaO或直接喷入的CaO的表面结构有关。本研究用同一石灰石经不同方法 (煅烧、过烧、煅烧 -水合 -脱水等 )制备了四种具有不同比表面积和孔结构的生石灰。高温脱硫研究表明 :这四种不同孔结构的生石灰 ,具有不同的脱硫率。通过对高温脱硫前后吸着剂宏观结构变化的对比 ,发现半径小于 30 的孔易被反应产物堵塞 ,因而脱硫能力有限 ,而半径大于 5 0 的孔对脱硫更有效。本研究将为提高炉内喷钙的脱硫率、研制和开发高效脱硫剂提供新的途径。     

燃煤工业锅炉排放二氧化硫对大气的污染及工业固硫型煤的应用

本文论述了我国燃煤工业锅炉排放ＳＯ２对大气污染的状况及发展趋势,以及应用工业固硫型煤控制燃煤工业锅炉对大气的污染。燃煤工业锅炉燃烧工业固硫型煤时,可明显地降低ＳＯ２和烟尘的排放量,并节约煤炭。在当前及今后相当长的时期内,推广和发展工业固硫型煤,是防治燃煤工业锅炉大气ＳＯ２污染的一条投资少、见效快、简便易行的实用措施,其经济效益及环境效益相当可观。     

Cross-Media Environmental Impacts of Air Pollution Regulations for a Coal-Fired Power Plant

The types and rates of pollutant emissions from a coal-fired power plant depend upon plant design, coal characteristics, and environmental control policy. In the past, air pollution regulations were often promulgated without rigorous analysis of the resulting energy penalties and secondary environmental impacts that occur in other environmental media (air, land, or water), which are counterproductive to overall environmental quality. This paper describes a Comparative Assessment Model that has been developed to consider systematically such tradeoffs for conventional and advanced coal-to-electric technologies. The model is applied to quantify the secondary (“cross-media”) environmental and resource impacts resulting from alternative air pollution control policies that reduce sulfur dioxide emissions from a 1000 MW power plant. Multimedia pollutant burdens are presented, together with the increased requirements for coal, limestone, and water that are incurred in generating a fixed net quantity of electricity. The development of sound public policy requires that environmental regulations be sensitive to adverse effects in all environmental media, and that tradeoffs involved in the regulation of specific pollutants to one medium be rigorously and systematically characterized.     

Sulfur Gas Emissions from Flue Gas Desulfurization Sludge Ponds

This paper presents initial measurement data on the emission of volatile, reduced sulfur-containing gases from flue gas desulfurization (FGD) storage ponds. Several different types of FGD stored sludges were studied including lime, limestone, and mixtures of fly ash and lime or limestone residues, some of which had been chemically stabilized. The volatile sulfur gas emissions were cryogenically concentrated and determined by wall-coated, open-tubular capillary column gas chromatography using a flame photometric detector. Hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, carbon disulfide, and an unusual, unidentified sulfur-containing compound were found in the gaseous pond flux. Benzene, toluene, and α-pinene were also identified by gas chromatography-single ion monitoring mass spectrometry. The total reduced sulfur gas emission from a 100 acre pond approximated 2.0 kg day^?1 (as sulfur).     

Fine Paniculate Removal and S02 Absorption with a Two Stage Wet Scrubber

This paper includes results from pilot plant studies and early field demonstration units and a discussion of the application of the limestone wet scrubbing process to a low sulfur syb-butuminous coal. This latter application required the development of a hybrid two stage scrubber to enable collection of the fine particulate matter as well as removal of a significant amount of the sulfur dioxide.     

Technical Description of Parameters Influencing the pH Value of Suspension Absorbent Used in Flue Gas Desulfurization Systems

Abstract

As a result of the large limestone deposits available in Poland, the low cost of reagent acquisition for the large-scale technological use and relatively well-documented processes of flue gas desulfurization (FGD) technologies based on limestone sorbent slurry, wet scrubbing desulfurization is a method of choice in Poland for flue gas treatment in energy production facilities, including power plants and industrial systems. The efficiency of FGD using the above method depends on several technological and kinetic parameters, particularly on the pH value of the sorbent (i.e., ground limestone suspended in water). Consequently, many studies in Poland and abroad address the impact of various parameters on the pH value of the sorbent suspension, such as the average diameter of sorbent particles (related to the limestone pulverization degree), sorbent quality (in terms of pure calcium carbonate [CaCO₃] content of the sorbent material), stoichiometric surfeit of CaCO₃ in relation to sulfur dioxide (SO₂) absorbed from flue gas circulating in the absorption node, time of absorption slurry retention in the absorber tank, chlorine ion concentration in sorbent slurry, and concentration of dissolved metal salts (Na, K, Mg, Fe, Al, and others). This study discusses the results of laboratory-scale tests conducted to establish the effect of the above parameters on the pH value of limestone slurry circulating in the SO₂ absorption node. On the basis of the test results, a correlation equation was postulated to help maintain the desirable pH value at the design phase of the wet FGD process. The postulated equation displays good coincidence between calculated pH values and those obtained using laboratory measurements.     

Pollution Control Progress

A scrubbing process for flue gas desulfurization, based upon naturally occurring carbonate rocks, has been developed from laboratory to pilot plant scale. Calcitic limestones are better sulfur dioxide absorbents than dolomitic ones when used in the slurry form. The process was tested on a 200-cfm pilot plant on a coal-fired boiler. Various types of scrubbing equipment were evaluated. Up to 80 per cent sulfur dioxide removal was feasible. The consumption of limestone ranged between 20 and 30 per cent more than the stoichiometric requirements.     

Continuous Monitoring for Sulfur Dioxide at A Utility Boiler Equipped with a Limestone Scrubber

The results of a 30-day sulfur dioxide monitoring program conducted at a utility boiler equipped with a limestone scrubber are presented. Program objectives were twofold: to demonstrate the reliable use of continuous monitoring equipment for determining scrubber performance and to support the proposed New Source Performance Standards (NSPS) published in the September 19, 1978, Federal Register. In general, continuous monitoring equipment is reliable as a source surveillance method. Results of the data collected indicate that the test site monitored was capable of performing under the guidelines of the proposed NSPS, and were incorporated in the final NSPS promulgated on June 11, 1979.     

Flue gas desulfurization: the state of the art

Coal-fired electricity-generating plants may use SO2 scrubbers to meet the requirements of Phase II of the Acid Rain SO2 Reduction Program. Additionally, the use of scrubbers can result in reduction of Hg and other emissions from combustion sources. It is timely, therefore, to examine the current status of SO2 scrubbing technologies. This paper presents a comprehensive review of the state of the art in flue gas desulfurization (FGD) technologies for coal-fired boilers. Data on worldwide FGD applications reveal that wet FGD technologies, and specifically wet limestone FGD, have been predominantly selected over other FGD technologies. However, lime spray drying (LSD) is being used at the majority of the plants employing dry FGD technologies. Additional review of the U.S. FGD technology applications that began operation in 1991 through 1995 reveals that FGD processes of choice recently in the United States have been wet limestone FGD, magnesium-enhanced lime (MEL), and LSD. Further, of the wet limestone processes, limestone forced oxidation (LSFO) has been used most often in recent applications. The SO2 removal performance of scrubbers has been reviewed. Data reflect that most wet limestone and LSD installations appear to be capable of approximately 90% SO2 removal. Advanced, state-of-the-art wet scrubbers can provide SO2 removal in excess of 95%. Costs associated with state-of-the-art applications of LSFO, MEL, and LSD technologies have been analyzed with appropriate cost models. Analyses indicate that the capital cost of an LSD system is lower than those of same capacity LSFO and MEL systems, reflective of the relatively less complex hardware used in LSD. Analyses also reflect that, based on total annualized cost and SO2 removal requirements: (1) plants up to approximately 250 MWe in size and firing low- to medium-sulfur coals (i.e., coals with a sulfur content of 2% or lower) may use LSD; and (2) plants larger than 250 MWe and firing medium- to high-sulfur coals (i.e., coals with a sulfur content of 2% or higher) may use either LSFO or MEL.