The study of electron beam flue gas treatment for coal-fired thermal plant in Japan

The fundamental research work with simulated coal-fired flue gas was performed in JAERI to get basic data for electron beam treatment of flue gas from thermal power plants in Japan. The standard condition of the experiments was set to be the same as that of next large scale pilot test in Nagoya. The concentrations of NO_x and SO_x were 225 ppm and 800 ppm, respectively. The temperature of the system was 65°C. The effect of multiple irradiation was observed for NO_x removal. The target SO_x and NO_x removals (94% and 80%, respectively) with low NH₃ leakage (less than 10 ppm) were achieved at 9 kGy irradiation with 0.9 NH₃ stoichiometry during 7 hours continuous operation. The facility for the pilot plant (12,000 Nm³/hr) has just built at the site of Shin-Nagoya power plant of Chubu Electric Power Company and will be started in full operation in November 1992.     

Contribution to electrical discharge electron beam system for flue gas cleaning method

Many authors have investigated simultaneous reduction of SO₂ and NO_x from flue gas stack emission by electron beam-induced plasma process. Because of high costs, this technology has been applied in only a few countries (Japan, China and Poland) until now. Small countries, consumers of cheap combustibles, produce a great deal of atmospheric pollutants SO₂ and NO_x, For this reason there is a great interest in the implementation of cheaper technologies with a similar impact as electron beam processing. This paper presents a series of experimental data for SO₂ and NO_x removal by electron beams, electric discharge and ozone in different processing variants of flue gas.     

Operational experience of a commercial scale plant of electron beam purification of flue gas

A commercial scale plant using electron beam irradiation was constructed to clean the flue gas from a coal fired thermal power plant at Chengdu in China. Operations began in September 1997 and the plant achieved its design performance with the satisfactory recovery of by-product fertilizer for agricultural use. Another commercial plant is now under construction at Nagoya, Japan and the operation will be started in November, 1999.     

Development of an up-flow irradiation device for electron beam wastewater treatment

Electron beam irradiation processing is an available technology to treat sludge, groundwater, surface water and industrial and municipal wastewater. The use of this technology into environmental areas has moved slowly because industry and government are always conservative in the adoption of new processes, especially when they can not observe the efficiency and cost effectiveness of a treatment in a full scale facility.

In this direction the hydraulic system where the water is presented to the electron beam governs the efficacy of this technology. The present work is based on the development of the irradiation device, an up-flow delivery system that alleviates the dependence of energy transfer to the stream with the beam accelerating voltage (penetration capability).

In this work a series of experiments were performed to establish the relationships between accelerating voltage ranging from 0.5 to 1.5 MeV, current, water flow and deposited dose in order to optimize the operating parameters and the selection of a cost-effective commercial electron beam.     

Kinetics of SO2 removal from flue gas by electron beam technique

Laboratory scale experiments were carried out in order to get more information about the oxidation of SO₂ by OH radicals (homogeneous reaction) and the oxidation of SO₂ at aerosol surfaces (heterogeneous reaction). For the experiment of homogeneous reaction, SO₂ was added to synthetic flue gas without initial NO and without ammonia and the mixture was irradiated with electron beam. The SO₂ removal was measured as a function of temperature and water vapour concentration at constant dose. For the experiment of heterogeneous reaction, SO₂ was added to nucleating sulfuric acid aerosol. No SO₂ removal was observed in this case. So, it can be concluded that the heterogeneous oxidation of SO₂ is negligible in the absence of ammonia. Therefore, the oxidation of SO₂ must be interpreted merely by homogeneous gas phase chemistry. The gas phase kinetics are derived from comparison of experimental results and computer modelling.     

电子束辐照与电化学还原联用技术——一种用于煤炭直接液化的新方法

对电子束辐照与电化学联用技术提高煤炭液化率的新型方法进行了研究。利用高能电子束对煤炭样品进行辐照,并通过四氢呋喃萃取出辐照后的可能产物并计算其提取率。实验结果发现,提取产率随着辐照剂量的增加而增加,并得到在氧气气氛下25 kGy的最佳辐照条件。辐照的样品进一步在氢氧化钠电解液中电化学还原液化,并采用元素分析法、傅里叶红外光谱法、阴极极化曲线法、核磁共振法和计时电流法等来检测辐照对煤炭电化学还原的影响。     

Application of electron beam irradiation combined to conventional treatment to treat industrial effluents

A preliminary study to combine electron beam irradiation process with biological treatment was carried out. Experiments were conducted using samples from a governmental wastewater treatment plant (WTP) that receives about 20% of industrial wastewater, with the objective of destroying the refractory organic pollutants and to obtain a better performance of this plant. Samples from five different steps of WTP were collected and irradiated in the electron beam accelerator in a batch system with 5.0, 10.0 and 20.0 kGy doses. The main results showed a removal of 99% of all organic compound analysed in the industrial receiver unit (IRU) effluent and in the coarse bar screen (CBS) effluent with a 20 kGy dose, and for the medium bar screen (MBS) and primary sedimentation (PS) effluent a 10 kGy dose was sufficient. In the case of final effluent (FE), a dose of 5 kGy removed the remaining organic compounds and dyes present after biological treatment.     

1-Chloronaphthalene decomposition in different gas mixtures under electron beam irradiation

The decomposition by electron beam (EB) irradiation of 1-chloronaphthalene in different gas matrices (air, N₂) was studied. Over 80% 1-chloronaphthalene was decomposed in air at 58 kGy dose when the initial concentration of 1-chloronaphthalene was 12–30 mg/Nm³. Over 50% 1-chloronaphthalene was decomposed in nitrogen when the initial concentration of 1-chloronaphthalene was 15–42 mg/Nm³.     

Electron beam forming system for irradiation of large diameter cylindrical products

The report describes electron beam electromagnetic forming system, which is destined for irradiation of cylindrical long goods, specifically for PE tubes 160 mm diameter. System consists of electromagnet, power supply units, beam distributions control units, etc. for use at an electron accelerator at 5 MeV and 50 kW. The particular geometry of the magnet poles and their mutual arrangement are creating an irradiation field that allows the electrons to irradiate the surface of the product close to 90°.     

Computer monitoring and control system (CMCS) for electron beam flue gas treatment

The computer monitoring and control system (VME based) with various facilities are described. The solution of preparing sampling probes and automatic calibration system is also presented.     

Analytical methods and monitoring system for E-beam flue gas treatment process

The results of reliable and precise measurement of gas composition in different key points of e-beam installation are necessary for its proper operation and control. Only the composition of flue gas coming into installation is adequate to composition of flue gas emitted from coal-fired boiler. At other points of e-b installation the gas composition is strongly modified by process conditions therefore specific measuring system (sampling and conditioning system and set of gas analyzers) for its determination are required. In the paper system for gas composition measurement at inlet and outlet of e-b installation are described. Process parameters are continuously monitoring by CEM system and occasionally by the grab sample system. Both system have been tested at pilot plant at EPS Kaw czyn.     

水对采空区遗煤吸附电厂烟气影响的理论计算

为研究电厂烟气注入采空区时,煤中含水率和烟气中水分对于封存温室气体CO_2和抑制煤自燃的影响,建立干煤和湿煤结构模型,采用巨正则系综蒙特卡洛方法,计算了不同水分含量的烟气组分CO_2/O_2/N2/H_2O在干煤以及不同含水率的湿煤中的吸附行为。结果表明,烟气中CO_2竞争性最强吸附量最大,O_2的物理吸附量极小,烟气中H_2O含量不影响CO_2、N2和O_2的吸附量,可不进行干燥处理直接将电厂烟气注入采空区。随着煤中含水率增加,水分占据孔隙空间,范德华作用减弱,H_2O-H_2O之间的氢键作用增强且提供了额外吸附位。H_2O的等量吸附热升高,吸附位移向吸附作用更强的低相互作用能区域,吸附大量水形成水团簇,与CO_2竞争吸附位,并且占据吸附空间抑制CO_2、O_2、N2的吸附,使其吸附量降低50%以上,因此,注入烟气时应充分考虑采空区煤体的含水率问题。     

燃煤烟气脱硫脱硝技术研究进展

综述了燃煤烟气脱硫脱硝技术研究进展,分析比较了目前烟气脱硫脱硝技术的优缺点;指出燃煤烟气脱硫脱硝技术是目前国内外燃煤烟气研究领域的一大热点,其中活性焦烟气脱硫脱硝技术是投入小、成本低、效益好的应用新技术,应用推广前景广阔.     

Kinetic modeling of benzene and toluene decomposition in air and in flue gas under electron beam irradiation

Computer simulations of benzene and toluene decomposition in air (79% N₂+21% O₂) and in flue gas (87% N₂+10% O₂+3% H₂O+160 ppm SO₂+80 ppm NO) under electron beam (EB) irradiation were carried out using computer code KINETIC and GEAR method. 285 reactions involving 73 species and 294 reactions involving 78 species were considered for simulation of benzene and toluene decomposition, respectively. Calculation results of benzene and toluene decomposition in air under electron beam agree well with the published experimental results. OH radicals play a main role in benzene or toluene decomposition.     

Hydrate capture CO2 from shifted synthesis gas,flue gas and sour natural gas or biogas

CO₂ capture by hydrate formation is a novel gas separation technology, by which CO₂ is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO₂ and other gases. However, rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO₂ capture. In this paper, the key problems in CO₂ capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas (CO₂/CH₄ system), the bottleneck is how to enhance the selectivity of CO₂ hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO₂ separation from shifted synthesis gas, flue gas and sour natural gas or biogas.     

烟气共存成分对微波辐照活性炭同时脱硫脱硝的影响研究

研究了O₂、CO₂以及水蒸气等各种烟气共存成分对微波辐照活性炭脱硫脱硝的影响。实验结果表明,SO₂对烟气脱硝有一定的抑制作用;烟气中水蒸气会抑制脱硫,低浓度水蒸气含量使脱硝效率上升,但高浓度水蒸气使脱硝效率下降;O₂和CO₂的存在可在一定程度上促进脱硫脱硝,但高浓度的O₂和CO₂会造成活性炭的损耗,从而抑制与脱硫和脱硝有关的还原反应。采用此方法可有效脱除烟气中SO₂和NO_{x,其脱除效率均在90%以上。}     

Remotion of organic compounds of actual industrial effluents by electron beam irradiation

Organic compounds has been a great problem of environmental pollution, the traditional methods are not effecient on removing these compounds and most of them are deposited to ambient and stay there for long time causing problems to the environment. Ionizing radiation has been used with success to destroy organic molecules. Actual industrial effluents were irradiated using IPEN's electron beam wastewater pilot plant to study organic compounds degradation. The samples were irradiated with and without air mixture by different doses. Irradiation treatment efficiency was evaluated by the Cromatography Gas Analyses of the samples before and after irradiation. The studied organic compounds were: phenol, chloroform, tetrachloroethylene (PCE), carbon tetrachloride, trichloroethylene (TCE), 1,1-dichloroethane, dichloromethane, benzene, toluene and xilene. A degradation superior to 80% was achieved for the majority of the compounds with air addition and 2kGy delivered dose condition. For the samples that were irradiated without air addition the degradation was higher.     

Effects of electron beam irradiation on cork volatile compounds by gas chromatography-mass spectrometry

Summary The effects of electron beam irradiation on cork volatile compounds was studied at different doses (25, 100, 1000 kGy). Volatiles were isolated from cork using the dynamic headspace-sampling technique, then identified by gas chromatography-mass spectrometry (GC-MS). Similar gas chromatographic profiles were obtained for non-irradiated and irradiated corks. Quantitative differences induced by the three doses were evaluated by calculating peak areas for each compound identified. The quantitative differences between non-irradiated corks and those irradiated at 25 kGy were significant for only a few substances, whereas significant quantitative differences were found in samples irradiated at 100 and 1000 kGy. For these doses, the content of volatile compounds generally increased, especially that of aliphatic hydrocarbons and carbonyl compounds. The behaviour of radiolytic hydrocarbons indicates that the mechanisms proposed for their formation in irradiated foods could take place even in cork.     

Pilot-scale test on electron beam treatment of municipal solid waste flue gas with spraying slaked-lime slurry

Simultaneous removal of NO_x, SO₂ and HCl in flue gas of a municipal solid waste incinerator was studied by using electron beam irradiation technology. The flue gas around of 1000 Nm³/h was led to a spray-dryer-type reactor from an inlet of ESP of the municipal waste incinerator by spraying slaked-lime slurry with one or more stoichiometic amount of the pollutants, concentrations of HCl (400 ppm) and SO₂ (50 ppm) decreased almost completely, while concentrations of NO_x (100 ppm) were markedly decreased to about 20 ppm by electron beam irradiation with a dose of 10 kGy at 150°C under spraying slaked-time slurry of two stoichiometric amounts. The removal of NO_x was improved by increasing the dose and the amount of spraying slaked-time slurry, and by lowering the irradiation temperature.     

添加剂对乙二胺湿法烟气脱硫的影响

采用自主设计的鼓泡吸收装置,以乙二胺溶液为脱硫剂,研究了盐酸、硫酸、磷酸、柠檬酸和硼酸作为添加剂对湿法烟气脱硫的影响。实验结果表明,加入酸添加剂后,提高了吸收液的有效吸收容量。其中,乙二胺/硼酸和乙二胺/磷酸的有效吸收容量较高,分别为266 mg/L和269 mg/L,pH值缓冲效果最佳。同时发现,乙二胺溶液的脱硫率随时间的延长而迅速减小;加入添加剂后,吸收液能在较长时间内保持较高脱硫率。10次吸收-解吸循环实验结果显示,乙二胺/硼酸、乙二胺/磷酸和乙二胺/柠檬酸的平均脱硫率均达99%,SO2解吸顺序为乙二胺/硼酸乙二胺/磷酸乙二胺/柠檬酸。硼酸和磷酸可强化乙二胺湿法烟气脱硫过程,是具有开发前景的添加剂。