脱硫废水毕业论文

燃煤火电厂紧凑式湿法烟气脱硫技术发布日期：2009-5-12 13:32:16 (阅130次)关键词: 烟气脱硫 脱硫 湿法脱硫引言我国目前的酸雨区已超过国土面积的三分之一，2005年的S排放量达到2549万t，超过总量控制指标749万t，加剧了我国的大气污染火电厂是S的主要排放源，我国2004年1月1日实施的GBl3223-2003《火电厂大气污染排放标准》按时段规定了火电厂的大气污染物最高允许排放值，加快了我国火电厂脱硫装置的投入使用，对于单机容量超过20MW的大型燃煤火电机组，国内外目前流行的脱硫工艺是采用湿法脱硫，在完成脱硫要求的同时，可以同时产生副产品石膏，实现脱硫副产品的资源再利用，我国现在运行的许多火电厂在原设计中没有考虑脱硫装置的安装位置，这使运行的火电厂增加脱硫装置带来了困难，未来10年装机容量3×10MW的火电机组均需要安装脱硫'>烟气脱硫装置，因此，我国现在运行的火电厂急需一种既具有高脱硫效率且节省占地面积的湿法脱硫新工艺，母公司为德国鲁尔集团公司(Ruhr AG)的德国斯特雅克集团公司(steag AG)自1969年开始研发以CaO或CaCO为脱硫剂的紧凑式湿法脱硫新工艺，该工艺具有脱硫效率高、占地面积小的独特优点，1977年在德国wilhelmshaven第一套具有商业化使用价值的紧凑式湿法脱硫工业化试验设备对5×10Nm/h的燃煤电厂烟气进行脱硫，相应的汽轮发电机组的电功率为140 MW；1982年第一台工艺脱硫设备在该电厂投入运行，脱硫的烟气量为×10Nm/h，相应的汽轮发电机组的电功率为450 MW，该工艺到2000年已成功应用的火电机组容量超过2×10MW，单台锅炉的最大额定烟气流量为×10Nm/h，单台汽轮发电机组的最大额定电功率为750MW，紧凑式湿法脱硫工艺特别适用于已运行电厂增加脱硫装置的改造方案，对我国大批火电厂的增加脱硫装置的改造方案具有重要的实用价值。1、燃煤火电厂紧凑式湿法脱硫工艺紧凑式湿法脱硫工艺的流程图如图1所示，来自电除尘器(1)温度为120～130％的待脱硫的烟气进入回转式烟气加热器(2)，把热量放给来自脱硫塔(4)温度为40～45℃的净化烟气，净化后的烟气是经过立式风机(3)使其压力升高来克服回转式烟气加热器的流动阻力，净化后的烟气温度升高到80～90％后排人烟囱(17)，以达到烟气进入烟囱的温度要求，放热后的烟气从脱硫塔底部进入脱硫塔向上流动，在脱硫塔内待脱硫的烟气与来自脱硫塔底部经泵(6)，升压后从分布在脱硫塔上部的喷嘴(5)喷出的脱硫剂浆液进行混合发生化学反应达到脱硫目的，化学反应产物从脱硫塔上部流向脱硫塔下部，与经风机(8)送人脱硫塔的空气进一步进行化学反应，形成脱硫'>烟气脱硫的副产品石膏的浆液，石膏浆液进入经浆泵(9)送人分离器(10)，分离出来的浓石膏浆液进入石膏生产系统(11)，产生石膏产品，从石膏生产系统(11)分离出来的废液与分离器(10)分离出来的废液进入混合器(12)，流出混合器(12)的浆液分成3部分，一部分进入脱硫剂制浆系统(16)，另一部分进入脱硫塔再循环利用，还有一部分经浆泵(13)升压后送人分离器(14)，分离出来的废水送入废水处理系统(15)进行净化处理，浆泵(7)将浆液升压后在脱硫塔下部进行搅拌，防止脱硫塔下部浆液沉淀，脱硫所需的工艺用水经水泵送入脱硫塔，随着脱硫剂的不断补充，就可以使脱硫系统连续运行，完成对烟气的连续脱硫。2、紧凑式湿法脱硫'>烟气脱硫工艺的应用实例紧凑式湿法脱硫工艺与常见的湿法脱硫工艺相比，主要差别是脱硫净化后的烟气经立式风机升压后送入回转式烟气加热器升温，然后再送人烟囱排入大气中。紧凑式湿法脱硫工艺已在德国、荷兰、土耳其、印尼、意大利、西班牙、巴西等十几个国家得到推广和应用，脱硫剂分别可以采用CaO、CaO/CaC03、海水，电厂的燃料可以是烟煤、褐煤、石油焦等，长期实际运行的脱硫效率从早期的90％达到目前的95％以上，最高可达％，列出了紧凑式湿法脱硫工艺的部分实例。德国对电厂排放要求十分严格，燃煤火电厂烟气的排放限定值S为400 mg/Nm脱硫效率要大于85％，NO为200 mg/Nm，烟尘50mg/Nm，这使电力生产中为环保支出的成本十分可观，在德国燃煤火力发电厂电力成本的构成中：燃料成本65％、湿法脱硫及生产石膏15％、脱氮成本9％、除尘成本5％、噪音治理2％、水费3％、厂区生态维护费用1％，德国燃煤电厂实际的烟气排放值优于排放限定值，某电厂脱硫'>烟气脱硫的实际运行记录绘出的烟气SO，出口含量和实际运行的脱硫效率，图中表明，脱硫前烟气中的SO浓度约为11000 mg/Nm，脱硫后烟气中的SO浓度约为33mg/Nm，脱硫效率为％紧凑式湿法脱硫过程产生的石膏产量可由下式计算。3、紧凑式湿法脱硫工艺应用过程中的改进措施在紧凑式湿法脱硫工艺的实用过程中，为了进一步提高该脱硫工艺的安全性、经济性和可靠性，主要进行了如下几个方面的技术改进：3、1提高设备运行的可靠性采用耐磨材料和螺旋型大口径喷嘴，解决了喷嘴的堵塞和磨损问题，不仅提高了喷嘴的耐磨性能和浆液流场的均匀性，而且使喷嘴的压差由改进前的 MP下降到 MP，实现了喷嘴节能超过30％。脱硫塔内部采用橡胶内衬结构，不仅节省了钢材，而且提高了脱硫塔的耐腐蚀性能，从而也提高了脱硫塔的使用寿命和运行可靠性。3、2减少脱硫装置的占地面积和初投资采用立式风机给进入烟气加热器的净化烟气升压，节省了紧凑式脱硫装置的安装尺寸，节约了烟气管道的长度，不仅可以大幅度降低烟气的流动阻力，而且节约了该脱硫工艺的占地面积和降低了该脱硫工艺的初投资，便于在已运行的燃煤机组上采用此脱硫工艺，如单机容量400 MW燃煤机组的脱硫塔的直径为，回转式烟气加热器的直径为10m。3、3优化脱硫工艺的运行方式和参数为了改善净化后的烟气中液体颗粒的分离效果，使气液分离器采用瓦楞板折返结构，在增加气液分离面积和增加气液分离流程的同时，降低了分离器的高度，从而也达到了降低脱硫塔高度的效果。在脱硫塔底部采用浆液循环搅拌措施，使脱硫塔底部的浆液的浓度变得十分均匀，提高了脱硫塔底部的容积有效利用率，从而降低了脱硫塔的高度，如930MW燃煤机组的锅炉高度为175m，而紧凑式脱硫塔的高度为48m。将脱硫塔内的喷嘴层设为6层，每两层喷嘴用一台浆泵供给喷嘴浆液，使喷嘴的流量可以调节，从而保证不同烟气SO浓度时均能达到较高的脱硫效率，以增强该脱硫工艺对燃料的适应性。经过上述改进措施的实施，使紧凑式湿法脱硫工艺具有改造费用低、节省占地面积、系统的安全性、经济性和可靠性都很高的一种新的湿法脱硫工艺，得到广泛推广和应用，成为运行中的大型燃煤电厂脱硫改造的首选新工艺。4、结束语紧凑式湿法脱硫工艺实际长期运行的脱硫效率现在已经超高95％，最高已达到98，5％，脱硫效率可以满足燃煤电厂脱硫效率的要求；紧凑式湿法脱硫工艺产生的脱硫石膏产品的质量和石膏中微量元素的含量，完全可以满足市场对石膏产品的质量要求，实现了脱硫副产品的资源化再利用；经过改进的紧凑式湿法脱硫工艺具有改造费用低、节省占地面积、系统的安全性、经济性和可靠性高等独特优点，是已运行的大型燃煤电厂脱硫改造的首选新工艺。本文来自: 环境技术网() 详细出处参考： thermal power plant compact wet flue gas desulfurization technologyRelease date :2009-5-12 13:32:16 (130 read)Key words: flue gas desulfurization desulfurization WFGDIntroductionAcid rain areas in China have more than one-third of the land area in 2005, emissions of S to reach million t, the total control of more than 7,490,000 t, exacerbated by air pollution in China's thermal power plant is the main source S, China's January 1, 2004 implementation GBl3223-2003 "thermal power plant air pollution emission standards," according to periods of thermal power plant provides the maximum allowable emissions of air pollutants the value of thermal power plants in China to speed up the desulfurization devices put into use, the stand-alone capacity more than 20MW of large-scale coal-fired thermal power units, both at home and abroad is currently popular is the use of wet FGD desulphurization, desulfurization requirements completed at the same time, it will also produce a by-product gypsum, FGD by-product of the realization of re-use of resources, China is now running a number of thermal power plants In the original design did not consider the installation of desulfurization equipment, which makes the operation of thermal power plant desulfurization devices to increase the difficulties brought about by the next 10 years the 3 × 10MW installed capacity of thermal power units are required to install desulfurization '> flue gas desulfurization devices, therefore, Our country is now in urgent need of running a thermal power plant not only has the high desulfurization efficiency and save the new area of the wet FGD process, the parent group for Germany's Ruhr (Ruhr AG) of Germany斯特雅克Group (steag AG) since R & D in 1969 for CaO or CaCO compact Desulfurizer WFGD new technology, the desulfurization process with high efficiency and small footprint of the unique advantages of wilhelmshaven in Germany in 1977 the first set of commercial value of the compact WFGD type of industrial test equipment 5 × 10Nm / h for coal-fired power plant flue gas desulfurization, the corresponding turbine-generator unit for the electric power 140 MW; 1982 in the first Taiwan-process desulfurization equipment in the plant put into operation, flue gas desulfurization capacity of × 10Nm / h, corresponding turbine-generator unit for the electric power 450 MW, the process that has been successfully applied in 2000 the thermal power unit capacity of more than 2 × 10MW, the largest single boiler flue gas flow rated × 10Nm / h, a single turbine-generator unit of the largest electric power for the rated 750MW, compact wet FGD process has been in operation is especially suitable for power plant desulfurization equipment to increase the transformation program, a large number of our thermal power plant desulfurization devices an increase in the transformation of program has an important practical , coal-fired thermal power plant technology of compact WFGDCompact wet FGD process flow chart as shown in Figure 1, from electrostatic precipitator (1) temperature of 120 ~ 130% of the flue gas desulfurization to be turning into the flue gas heater (2), the heat released to the from the desulfurization tower (4) temperature of 40 ~ 45 ℃ flue gas purification, after purification of the flue gas is the result of vertical fan (3) to overcome the increased pressure to turn the flow of flue gas heater resistance, purified flue gas temperature to 80 ~ 90% of people behind the chimney (17), in order to achieve the temperature of flue gas entering the chimney request, after the heat from the flue gas desulfurization tower at the bottom of upward mobility into the desulfurization tower, to be in the desulfurization tower Desulfurization of flue gas desulfurization tower from the bottom by the pump (6), step-up from the desulfurization tower located in the upper part of the nozzle (5) out of the mixed slurry desulfurizer chemical reaction to achieve the purpose of desulfurization, chemical reaction products from the desulfurization Tap the bottom of the upper part of the flow of desulfurization tower, with the fan (8) give the air desulfurizer further chemical reaction, the formation of desulfurization '> FGD gypsum by-product of the slurry, gypsum slurry into the pump through (9) give separator (10), separated into the dense slurry gypsum plaster production systems (11), resulting in gypsum products, gypsum production system from (11) separated from the liquid and the separator (10) separated from the liquid into the mixer (12 ), outflow mixer (12) of the slurry into 3 parts into the system desulfurizer Pulp (16), another part of recycling into the desulfurization tower, some by the pump (13) give separator after boost (14), separated from the wastewater into the wastewater treatment system (15) for purification, pump (7) after the slurry desulfurizer boost to stir the bottom, to prevent the lower part of serous desulfurizer precipitation, water desulfurization process required by the pump into the desulfurization tower, with the constant desulfurizer added that allow continuous operation of desulfurization systems, to complete a continuous flue gas , compact WFGD '> FGD application processCompact wet FGD process with common wet FGD process, the main difference is the desulfurization of flue gas purification by following the step-up into the vertical rotary fan flue gas heater to heat up, and then send the person into the air chimney wet FGD process has been in Germany, the Netherlands, Turkey, Indonesia, Italy, Spain, Brazil and other countries has been the promotion and application, respectively, can be used desulfurizer CaO, CaO/CaC03, water, fuel for power plants can be bituminous coal, lignite, petroleum coke, etc., long-term operation of the desulfurization efficiency of 90% from early to reach more than 95% of the current up to , are listed in the compact part of wet FGD process has very strict requirements of power plant emissions, coal-fired thermal power plant flue gas emission limit value of S for the 400 mg / Nm desulfurization efficiency is greater than 85%, NO for the 200 mg / Nm, dust 50mg/Nm, which makes power production the cost of expenditures for environmental protection is very impressive, in Germany the cost of electricity coal-fired power plants in the composition: 65% of fuel costs, the production of gypsum wet FGD and 15%, 9% of the cost of removal, the cost of 5% of dust, noise control 2% , 3 percent water, plant maintenance costs 1% of the ecological, the German coal-fired power plant flue gas emissions from the actual value than the emission limit values, a power plant desulfurization '> FGD drawn record of the actual operation of the flue gas SO, export content and practical operation of the desulfurization efficiency, the figure shows that before the flue gas desulfurization of SO concentration is about 11000 mg / Nm, after the desulfurization of flue gas concentration of SO of about 33mg/Nm, desulfurization efficiency of percent of compact wet FGD gypsum produced by the process of production can be , compact wet FGD process applications in the process of improvement measuresIn the compact utility wet FGD process, in order to further enhance the desulfurization process of the security, economy and reliability, mainly the following aspects of the technical improvements:3,1 to improve the reliability of equipmentWear-resistant materials and the use of large diameter spiral nozzles, nozzle solve the problem of congestion and wear and tear, not only improve the wear resistance and serous nozzle flow field uniformity, but also pressure from the nozzle to improve the pre-fell to MP MP, achieved more than 30% energy-saving internal structure of the use of rubber-lined, steel not only saves, but also enhanced the desulfurization tower corrosion resistance, and thus improve the life of the desulfurization tower and operating desulfurization equipment to reduce the footprint and the initial investmentThe use of vertical flue gas fan heater to enter the flue gas purification step, saving compact size of the installation of desulfurization equipment, saving the length of the gas pipeline, not only can greatly reduce the flow of flue gas resistance, and to save the Desulfurization of the area and reduce the initial investment in desulfurization technology for the coal-fired units have been in operation for the use of this desulfurization process, such as stand-alone capacity of 400 MW coal-fired units in the desulfurization tower diameter of , rotary the diameter of gas-gas heater of 3,3-FGD operation mode and parametersIn order to improve the purification of the flue gas after the separation of liquid particles, so that the use of gas-liquid separator returned to the structure of corrugated board, after an increase in size and increase in gas-liquid separation processes, gas-liquid separator at the same time, reduce the height of the separator, which also reached to reduce the effect of a high degree of desulfurization in the desulfurization tower at the bottom of the cycle slurry mixing measures to desulfurizer the concentration of slurry at the bottom become very uniform, increased volume at the bottom desulfurizer effective utilization, thereby reducing the height of the desulfurization tower, such as coal-fired units of 930MW Boiler height for the 175m, while the compact desulfurization tower height of tower will set the nozzle layer 6 layers, each with a two-tier nozzle pump slurry supply nozzle so that the flow of the nozzle can be adjusted to ensure that flue gas SO different concentration can reach the high desulfurization efficiency, in order to enhance the desulfurization process of adaptation of the above-mentioned measures to improve implementation of the compact wet FGD process with a modified low-cost, save area, the system's security, economy and reliability are very high, a new wet FGD process has been widely and applications, to become in the operation of the transformation of large-scale coal-fired power plant of choice for a new desulfurization , concluding remarksCompact actual wet desulfurization process of long-term operation of ultra-high desulfurization efficiency of 95 percent now, the maximum has reached 98,5%, the efficiency of desulfurization desulfurization efficiency coal-fired power plants to meet the requirements;Compact Wet FGD gypsum produced by the quality and content of trace elements in gypsum, plaster fully meet the market requirements of product quality to achieve desulfurization by-product of re-use of resources;Compact improved wet FGD process with a modified low-cost, save area, the system's security, economy and the unique advantages of high reliability is already running a large-scale coal-fired power plant desulfurization new technology of choice for article from: Environmental Technology Network () detailed reference to the source: