Electron Beam Flue Gas Treatment Research Articles

A high-efficiency and eco-friendly design for coal-fired power plants: Combined waste heat recovery and electron beam irradiation

To ensure the sustainable development of the economy and society, energy-saving and emission reduction is an inevitable choice to solve resource scarcity and control environmental pollution, while coal-fired power plants are an important industry to implement this strategy. A novel design combining organic Rankine cycle with electron beam flue gas treatment is proposed to reduce pollutant emissions and recover flue gas waste heat of 600 MW power plant. The flue gas flows through the organic Rankine cycle to recover waste heat, then enters the electron beam irradiation device for desulfurization-denitrification, and eventually generates by-products of ammonium sulfate and ammonium nitrate that could be applied in agriculture. The particle swarm optimization algorithm is employed to improve the thermodynamic, economic and environmental performance, then the most suitable scheme is selected by combining TOPSIS and the entropy weight method. The optimization results indicate that the integrated system could produce equivalent electric quantity of 22.58 MW, and the payback period is 4.91 years. Meanwhile, ammonium sulfate and nitrate with production of 3544 kg/h and 6165 kg/h are obtained. Compared with the referenced power plant, the thermal efficiency of the improved scheme increases by 1.26% and the standard coal consumption rate decreases by 2.72%.

Plasma technology to remove NOx from off-gases

Abstract Operation of marine diesel engines causes significant emission of sulphur and nitrogen oxides. It was noticed worldwide and the regulations concerning harmful emissions were introduced. There were several solutions elaborated; however, emission control for both SOx and NOx requires two distinctive processes realized in separated devices, which is problematic due to limited space on ship board and high overall costs. Therefore, the electron beam flue gas treatment (EBFGT) process was adopted to ensure the abatement of the problem of marine diesel off-gases. This novel solution combines two main processes: first the flue gas is irradiated with electron beam where NO and SO2 are oxidized; the second stage is wet scrubbing to remove both pollutants with high efficiency. Laboratory tests showed that this process could be effectively applied to remove SO2 and NOx from diesel engine off-gases. Different compositions of absorbing solution with three different oxidants (NaClO, NaClO2 and NaClO3) were tested. The highest NOx removal efficiency (>96%) was obtained when seawater-NaClO2-NaOH was used as scrubber solution at 10.9 kGy dose. The process was further tested in real maritime conditions at Riga shipyard, Latvia. More than 45% NOx was removed at a 5.5 kGy dose, corresponding to 4800 Nm3/h off-gases arising from ship emission. The operation of the plant was the first case of examination of the hybrid electron beam technology in real conditions. Taking into account the experiment conditions, good agreement was obtained with laboratory tests. The results obtained in Riga shipyard provided valuable information for the application of this technology for control of large cargo ship emission.

Removal of NOx using electron beam process with NaOH spraying

Nitrogen oxides (NOx; NO and NO2) are major air pollutants and can cause harmful effects on the human body. Electron Beam Flue Gas Treatment (EBFGT) is a technology that generates electrons with an energy of 0.5–1 MeV using electron accelerators and effectively processes exhaust gases. In this study, NOx was removed using an electron beam accelerator with spraying additives (NaOH and NH4OH). NO and NO2 were 100% and more than 94% removed, respectively, at an electron beam absorbed dose of 20 kGy and an additive concentration of 0.02 M (mol/L). In most cases, NOx was removed better with lower initial NOx concentrations and higher electron beam absorbed doses. As the irradiation strength (mA) of the electron beam increases, the probability of electron impact on the material accordingly rises, which may lead to increase removal efficiency. The results of the present study show that the continuous electron beam process using additives achieved more effective removal efficiency than either individual process (wet-scrubbing or EB irradiation only).

Application of electron accelerator for flue gas treatment of coal power plant to support green technology

Fossil fuels, which include coal, natural gas, petroleum, shale oil, and bitumen, are the main source of heat and electrical energy, but burning these fuels will emit pollutants to the environment. Most countries use coal burning power plant in generating electricity for living needs such as household electricity and industrial development. This power plant generates large quantities of pollutants (SOX and NOX) that create acid rain and smog leading to the water and soil degradation and they can affect living things. To meet rising worldwide energy demand, projections call for the use of coal to increase by 50 percent from 2006 - 2030, as a consequence SOX and NOX pollutions will rise. There are two conventional technologies to decrease air pollution from coal power plant, the first is FGD (flue gas desulfurization) based on SO2 absorption in lime or limestone slurry; and the second is SCR (selective catalytic reduction) based on NOx reduction over a catalyst to atmospheric nitrogen with ammonia as a reductant. But these technologies cannot treat different pollutants in one step process. To support green technology program, this paper describes a modern technology called EBFGT (electron beam flue gas treatment) which can treat SOx and NOx in one step process using electron accelerator. The technology and economy comparison between FGD, SCR, EBFGT as well as the existing EBFGT in the world are compiled.

Electron beam flue gas technology for SOx and NOx simultaneous removal: its process and chemistry evolution from power plants to diesel off-gas treatment

Abstract Environmental pollution is one of the most important problems in present-day society. Governments and international organizations try to mitigate this problem by enforcing strict laws concerning the emission of certain pollutants. This process is especially rapidly applied concerning air pollution. In the past, the main focus was placed on the regulation of the energy sector and of land-based transportation emissions, as they produce the vast majority of pollutants. Today, the emphasis is shifted toward marine-based transportation, as it is anticipated that after the year 2020, the emission from sea-based sources (with respect to sulfur and nitrogen oxides) will exceed the land-based emission. One of the technologies that have been successfully implemented in industries to decrease the level of air pollution caused by NOx and SOx is electron beam flue gas treatment. This review shows the chemical principles of this method as well as the chemical engineering issues and its development and modifications to suit the changing needs of industries worldwide.

Environmentally friendly treatment of airpollutants: evaluation of cumulative process for flue gas treatment

This paper proposes the combination of two different domains; the environment and agriculture. Emission of sulfur oxides and nitrogen oxides is associated with global acidification (e.g. acid rain), and it has become a serious environmental problem. Meanwhile, the amount of fertilizer consumed globally in 1996 was over 6 times that consumed in 1960. Electron beam flue gas treatment (a dry process) can simultaneously convert sulfur dioxide, sulfur trioxide and nitrogen oxides into nitrogen fertilizer. This process has been considered costly. An electron beam industrial plant has been built and is currently operating. The data delivered from this industrial plant proves that economic performance of the electron beam process is about the same as that of the conventional wet limestone process.

A hybrid plasma-chemical system for high-NOx flue gas treatment

The reduction of high concentrations of NOx and SO2 from simulated flue gas has been studied. Our aim was to optimise energy consumption for NOx and SO2 removal from off-gases from a diesel generator using heavy fuel oil. A hybrid process: electron beam (EB) plasma and wet scrubber has been applied. A much higher efficiency of NOx and SO2 removal was achieved in comparison to dry, ammonia free, electron beam flue gas treatment (EBFGT). A recorded removal from a concentration of 1500ppm NOx reached 49% at a low dose of 6.5kGy, while only 2% NOx was removed at the same dose if EB only was applied. For SO2, removal efficiency at a dose of 6.5kGy increased from 15% (EB only) to 84% when sea water was used as a wet scrubber agent for 700ppm SO2. The results of this study indicate that EB combined with wet scrubber is a very promising technology to be applied for removal of high concentrations of NOx and SO2 emitted from diesel engines operated e.g. on cargo ships, which are the main sources of SO2 and NOx pollution along their navigation routes.

A kinetic sensitivity analysis for the SO2 and NOx removal using the electron beam technology

The mathematical modeling of the phenomena taking place during the electron beam flue gas treatment is a complex endeavor due to the different time scales of the processes occurring as accelerated electrons are bombarding the flue gas. The paper presents a complex kinetic model for these gas phase interactions, consisting of 1034 chemical reactions with the participation of 115 reactive species. The mathematical model couples the complex gas phase kinetics with a liquid phase kinetic model, taking into account the nucleation and condensation phenomena occurring due to the presence of sulfuric acid. The modeling results for both coupled and uncoupled gas phase kinetics are validated against a set of literature experimental data with satisfactory outcome. The work aims to identify the most important chemical reactions influencing the pollutants removal, proposing a sensitivity analysis using the concept of generated entropy. To the best of the authors’ knowledge a sensitivity analysis of this extent has not been performed for the electron beam flue gas treatment. The results of this analysis emphasize the link between the removal efficiencies of NOx and SO2, the importance of hydroxyl radicals and can aid in future model reduction efforts.

Analysis of mixing conditions and multistage irradiation impact on NOx removal efficiency in the electron beam flue gas treatment process

ABSTRACTIn the process of electron beam flue gas treatment (EBFGT), most energy is spent on NOx removal. The dose distribution in the reactor is not uniform and the flue gas flow pattern plays an important role in the process efficiency. It was found that proper construction of the reactor may increase the energy efficiency of the process. The impact of the number of irradiation stages and mixing conditions on NOx removal efficiency was investigated for an ideal case and a practical solution was presented and compared with previously known EBFGT reactor constructions. The research was performed by means of computational fluid dynamics methods in combination with empirical Wittig formula. Two versions of dose distribution were taken for calculations. The results of the research show that for an ideal case, application of multistage irradiation and interstage mixing may reduce the energy consumption in the process by up to 39%. On the other side, simulation of reactor construction modification for two-stage irradiation results in 25% energy consumption reduction. The results of presented case study may be applied for improving the existing reactors and proper design of future installations.

Pilot plant for electron beam treatment of flue gases from heavy fuel oil fired boiler

The pilot scale electron beam flue gas treatment (EBFGT) plant was constructed at Saudi Aramco's Refinery in Jiddah, Saudi Arabia. The plant was designed to treat 2000Nm3/h of flue gas emitted from a heavy fuel oil fired boiler. A unique mobile electron accelerator unit (600keV, 20kW) made by EB TECH Co., Ltd., Korea was used as a beam source. The pilot plant operation proved the high potential of the technology for simultaneous control of sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions. The obtained removal efficiencies reached 98.5% for SO2 and 83.1% for NOx. Two types of byproduct collection devices – cartridge bag filter and electrostatic precipitator – were tested. The obtained byproduct was a high quality fertilizer that can be used directly or as a substrate for NPK blends manufacturing. The soluble part of the byproduct was almost pure ammonium sulfate (98% to 99%) with some amount of ammonium nitrate. The content of heavy metals in the byproduct was very low and lower than the allowed standards by two orders of magnitude. The results of the research are the basis for the design of a full industrial scale EBFGT plant for treatment of flue gas from heavy fuel oil combustion.

New “wet type” electron beam flue gas treatment pilot plant

Abstract We describe a new pilot plant for flue gas cleaning by a high energy electron beam. The special feature of this pilot plant is a uniquely designed reactor called VGS® (VIVIRAD Gas Scrubber, patent pending), that allows oxidation/reduction treating flue gas in a single step. The VGS® process combines a scrubber and an advanced oxidation/reduction process with the objective of optimizing efficiency and treatment costs of flue gas purification by electron accelerators. Promising treatment efficiency was achieved for SOx and NOx removal in early tests (99.2% and 80.9% respectively). The effects of various operational parameters on treatment performance and by-product content were investigated during this study.

Electron beam treatment of simulated marine diesel exhaust gases

Abstract The exhaust gases from marine diesel engines contain high SO2 and NOx concentration. The applicability of the electron beam flue gas treatment technology for purification of marine diesel exhaust gases containing high SO2 and NOx concentration gases was the main goal of this paper. The study was performed in the laboratory plant with NOx concentration up to 1700 ppmv and SO2 concentration up to 1000 ppmv. Such high NOx and SO2 concentrations were observed in the exhaust gases from marine high-power diesel engines fuelled with different heavy fuel oils. In the first part of study the simulated exhaust gases were irradiated by the electron beam from accelerator. The simultaneous removal of SO2 and NOx were obtained and their removal efficiencies strongly depend on irradiation dose and inlet NOx concentration. For NOx concentrations above 800 ppmv low removal efficiencies were obtained even if applied high doses. In the second part of study the irradiated gases were directed to the seawater scrubber for further purification. The scrubbing process enhances removal efficiencies of both pollutants. The SO2 removal efficiencies above 98.5% were obtained with irradiation dose greater than 5.3 kGy. For inlet NOx concentrations of 1700 ppmv the NOx removal efficiency about 51% was obtained with dose greater than 8.8 kGy. Methods for further increase of NOx removal efficiency are presented in the paper.

Comparative life cycle assessment of plasma-based and traditional exhaust gas treatment technologies

The emissions of airborne contaminants from various industrial processes are an important source of air pollution and presents problems for human health and the environment in general. The removal of gaseous pollutants, such of nitrogen and sulphur oxides (NOx and SOx), from exhaust gases, or volatile organic compounds (VOC) emitted from various industrial processes is of continuous challenge in the environmental engineering. Plasma-based pollutant decomposition methods emerge as promising techniques, but little is known about their overall environmental performance. We compared two plasma based technologies (Electron Beam Flue Gas Treatment (EBFGT) and Dielectric Barrier Discharge (DBD) against the conventional methods (Wet Flue Gas Desulphurization with Selective Catalytic Reduction, WFGD+SCR, biofiltration and adsorption) using life cycle analysis (LCA), which took into account the usage of materials, waste generation and energy consumption. Five main categories (Global Warming, Ozone Layer Depletion, Acidification, Euthrophication and Human Toxicity, based on the CML2001 method) were used for the environmental impact evaluation. Based on CML2001 IKP Experts weighting, WFGD+SCR technology is marginally more environmentally friendly in comparison to EBFGT (59.25 to 73.74 CML2001 IKP Experts score). The generation of byproducts (in this case gypsum waste) is the main disadvantage of the WFGD+SCR. At the same time, EBFGT enables formation of useful byproducts, which are suitable to be utilized as fertilizers in the agriculture sector. On the other hand, DBD was six times more favorable to the environment than the adsorbtion and more than two times more environmentally friendly than the biofiltration technology (4.23, 27.78 and 9.29 relative units, respectively). With respect to the adsorption/thermal incineration of VOCs, both the electricity and the material consumption, as well as the management of byproducts caused the highest impact. In case of biofiltration, the management of remaining filter material waste (in this case, landfilling) was the most significant. Relatively high electrical energy demand causes lower positioning of plasma based technologies in cases where no other materials are utilized and major waste is formed. In turn, many traditional end-of pipe technologies are associated with high amounts of process waste, which provides plasma technologies with an opportunity to establish them in the market as more efficient and in many occasions, more environment-friendly ones.

E-Beam SO2 and NOx removal from flue gases in the presence of fine water droplets

The Electron Beam Flue Gas Treatment (EBFGT) has been proposed as an efficient method for removal of SO2 and NOx many years ago. However, the industrial application of this procedure is limited to just a few installations. This article analyses the possibility of using medium-power EB accelerators for off-gases purification. By increasing electron energy from 0.7MeV to 1–2MeV it is possible to reduce the energy losses in the windows and in the air gap between them (transformer accelerators can be applied as well in the process). In order to use these mid-energy accelerators it is necessary to reduce their penetration depth through gas and this can be achieved by increasing the density of the reaction medium by means of dispersing a sufficient amount of fine water droplets (FWD). The presence of FWD has a favorable effect on the overall process by increasing the level of liquid phase reactions. A special reactor was designed and built to test the effect of FWD on the treatment of flue gases with a high concentration of SO2 and NOx using high-energy EBs (9MeV). By determining the energy efficiency of the process the favorable effect of using FWD and high-energy EB was demonstrated.

Basic technology for developing cost-effective thermal waste recycling industry

The advantages of electron-beam treatment of flue gases of industrial and power plants are discussed. The equations of the basic chemical reactions are presented, and a mathematical model of the cleaning process is developed. A conclusion on the self-repayment of this technology was drawn, which opens up new prospects for its implementation.

Electron Beam Technology for Multipollutant Emissions Control from Heavy Fuel Oil-Fired Boiler

The electron beam treatment technology for purification of exhaust gases from the burning of heavy fuel oil (HFO) mazout with sulfur content approximately 3 wt % was tested at the Institute of Nuclear Chemistry and Technology laboratory plant. The parametric study was conducted to determine the sulfur dioxide (SO2), oxides of nitrogen (NOx), and polycyclic aromatic hydrocarbon (PAH) removal efficiency as a function of temperature and humidity of irradiated gases, absorbed irradiation dose, and ammonia stoichiometry process parameters. In the test performed under optimal conditions with an irradiation dose of 12.4 kGy, simultaneous removal efficiencies of approximately 98% for SO2 and 80% for NOx were recorded. The simultaneous decrease of PAH and one-ringed aromatic hydrocarbon (benzene, toluene, and xylenes [BTX]) concentrations was observed in the irradiated flue gas. Overall removal efficiencies of approximately 42% for PAHs and 86% for BTXs were achieved with an irradiation dose 5.3 kGy. The decomposition ratio of these compounds increased with an increase of absorbed dose. The decrease of PAH and BTX concentrations was followed by the increase of oxygen-containing aromatic hydrocarbon concentrations. The PAH and BTX decomposition process was initialized through the reaction with hydroxyl radicals that formed in the electron beam irradiated flue gas. Their decomposition process is based on similar principles as the primary reaction concerning SO2 and NOx removal; that is, free radicals attack organic compound chains or rings, causing volatile organic compound decomposition. Thus, the electron beam flue gas treatment (EBFGT) technology ensures simultaneous removal of acid (SO2 and NOx) and organic (PAH and BTX) pollutants from flue gas emitted from burning of HFO. This technology is a multipollutant emission control technology that can be applied for treatment of flue gas emitted from coal-, lignite-, and HFO-fired boilers. Other thermal processes such as metallurgy and municipal waste incinerators are potential candidates for this technology application.

Electron beam flue gas treatment (EBFGT) technology for simultaneous removal of SO 2 and NO x from combustion of liquid fuels

Electron beam flue gas treatment technology was applied for removal of SO 2 and NO x from flue gas, emitted from combustion of high-sulfur fuel oils. The detailed study of this process was performed in a laboratory by irradiating the exhaust gas from the combustion of three grades of Arabian fuels with an electron beam from accelerator (800 keV, max. beam power 20 kW). SO 2 removal is mainly dependent on ammonia stoichiometry, flue gas temperature and humidity and irradiation doses up to 8 kGy. NO x removal depends primarily on irradiation dose. High removal efficiencies up to 98% for SO 2 and up to 82% for NO x were obtained under optimal conditions. The flue gas emitted from combustion of high-sulfur fuel oils, after electron beam irradiation, meets the stringent emission standards for both pollutants. The by-product, which is a mixture of ammonium sulphate and nitrate, can be used as a fertilizer as such or blended with other components to produce commercial agricultural fertilizer.

Industrial applications of electron beam flue gas treatment—From laboratory to the practice

The electron beam technology for flue gas treatment (EBFGT) has been developed in Japan in the early 1980s. Later on, this process was investigated in pilot scale in the USA, Germany, Japan, Poland, Bulgaria and China. The new engineering and process solutions have been developed during the past two decades. Finally industrial plants have been constructed in Poland and China. The high efficiency of SO x and NO x removal was achieved (up to 95% for SO x and up to 70% for NO x ) and by-product is a high quality fertilizer. Since the power of accelerators applied in industrial installation is over 1 MW and requested operational availability of the plant is equal to 8500 h in year, it is a new challenge for radiation processing applications.

Radiation technologies: past, present and future

The radiation technologies applying gamma sources and electron accelerators for material processing are well-established processes. New fields concerning radiation sources are development of compact size gamma irradiators, high-power accelerators with direct e −/X conversion and low-energy EB processing systems. The technologies to be developed besides environmental applications, could be nanomaterials, structure engineered materials (sorbents, the composites, ordered polymers, etc.) and natural polymers processing. The International Atomic Energy Agency (the Agency) has been involved in the support of projects related to the application of radiation technology for many years. Due to its assistance, advanced radiation processing centers were established in many countries. New materials and processes were developed as well: wound hydrogel dressing, radiation vulcanized latex, industrial plant for electron beam flue gas treatment, pilot plant for electron beam wastewater treatment and others.

Operational experience of the industrial plant for electron beam flue gas treatment

Electron beam flue gas treatment technology is one of the most advanced technologies among new generation processes for air pollution control. The process, which has been developed in Japan, the United States, Germany and Poland allows simultaneous removal of SO 2 and NO x with high efficiency and by-product generated can be applied as fertilizer. Two industrial installations using this technology have been constructed in the world, one in China and the second in Poland. Other plants are constructed in Japan and China. Chinese installation is mostly SO 2 removal oriented (since the NO x emission limits in China are not imposed up to now), so Polish plant one is as a matter of fact the first installation for simultaneous desulfurization and denitrification of flue gases. The plant located in EPS Pomorzany in Szczecin treats the flue gases emitted from two Benson boilers of 65 MW e and 100 MW th each. The flue gases of maximum flow of 270 000 N m 3/h are irradiated by four accelerators of 700 keV electron energy and 260 kW beam power each. Description of the plant and the results obtained have been presented in this paper. The plant has been in operation for more than 2500 h (5500 h including one accelerator set operation). Removal efficiencies up to 95% for SO 2 and up to 70% for NO x were achieved. Several thousand tons of the by-product was sold in the form of NPK fertilizer. Economically, the technology is competitive with the conventional ones.