Boiler Flue Gas Research Articles

The measurement of dew point

A sensor of the dew point of the flue gases of boilers and other installations is described, based on the occurrence of an emf between unlike metals when moisture from the flue gases is deposited.

Simulation of a combined Rankine–absorption cycle

A simulation of a combined Rankine–absorption cycle is presented in which the boiler flue gases of the Rankine cycle are used as an energy source to the absorption cycle that is used to cool the Rankine cycle condenser to offset the performance degradation of the Rankine cycle when operating under high ambient temperature conditions. The results indicate that there is insufficient energy in the flue gases for a single effect absorption unit to improve the overall cycle performance to that of an ISA day case. The analysis concludes by indicating the level of coefficient of performance (COP) that would be needed to achieve the desired objective.

Gas-Phase Mercury Reduction to Measure Total Mercury in the Flue Gas of a Coal-Fired Boiler

Gaseous elemental and total (elemental + oxidized) mercury (Hg) in the flue gas from a coal-fired boiler was measured by a modified ultraviolet (UV) spectrometer. Challenges to Hg measurement were the spectral interferences from other flue gas components and that UV measures only elemental Hg. To eliminate interference from flue gas components, a cartridge filled with gold-coated sand removed elemental Hg from a flue gas sample. The Hg-free flue gas was the reference gas, eliminating the spectral interferences. To measure total Hg by UV, oxidized Hg underwent a gas-phase, thermal-reduction in a quartz cell heated to 750°C. Simultaneously, hydrogen was added to flash react with the oxygen present forming water vapor and preventing Hg re-oxidation as it exits the cell. Hg concentration results are in parts per billion by volume Hg at the flue gas oxygen concentration. The modified Hg analyzer and the Ontario Hydro method concurrently measured Hg at a field test site. Measurements were made at a 700-MW steam turbine plant with scrubber units and selective catalytic reduction. The flue gas sampled downstream of the selective catalytic reduction contained 2100 ppm SO2 and 75 ppm NOx. Total Hg measured by the Hg analyzer was within 20% of the Ontario Hydro results.

Landfill is an important at-mospheric mercury emission source

Since municipal wastes contain refuses with high mercury contents, incineration of municipal wastes becomes the major anthropogenic atmospheric mercury emission source. In China, landfills are however the main way to dispose of municipal wastes. Total gaseous mercury (TGM) concentrations in landfill gas of Gaoyan sanitary landfill located in suburb of Guiyang City were monitored using a high temporal resolved automated mercury analyzer, and mono-methylmercury (MMHg) and dimethylmercury (DMHg) concentrations in landfill gas were also measured using GC coupled with the cold vapor atomic fluorescence (CVAFS) method. Meanwhile, the TGM exchange fluxes between exposed waste and air and the soil surface of the landfill and air, were measured using low Hg blank quartz flux chamber coupled with high temporal resolved automated mercury analyzer technique. TGM concentrations in landfill gas from half year filling area averaged out at 665.52 ±291.25 ng/m3, which is comparable with TGM concentrations from flue gas of a small coal combustion boiler in Guiyang. The average MMHg and DMHg concentrations averaged out at 2.06 ±1.82 ng/m3 and 9.50±5.18 ng/m3, respectively. It is proven that mercury emission is the predominant process at the surfaces of both exposed wastes and soil of landfill. Landfills are not only TGM emission source, but also methylmercury emission source to the ambient air. There are two ways to emit mercury to the air from landfills, one is with the landfill gas through landfill gas duct, and the other through soil/air exchange. The Hg emission processes from landfills are controlled by meteorological parameters.

Nonthermal Plasma Electrocatalytic Reduction of Nitrogen Oxide

The high cost of a currently available selective catalytic reduction (SCR) process is driving R&D efforts toward finding alternative technologies to remediate NO emissions from utility boilers. A hybrid plasma−catalyst (P−C) system is investigated for NOx removal. The plasma (dielectric barrier discharge) and SCR techniques are each studied for the reduction of NOx for comparative purposes. γ-Al2O3 is used as a catalyst in the hybrid P−C system. The hybrid P−C experiments show effective NOx removal compared to the results obtained from either plasma or SCR experiments. NOx removal by the P−C system is about 15% higher compared to that by the SCR alone when 1000−3000 ppm of methane or ethylene is added to the inlet gas stream. The hybrid P−C system has the potential to be successfully used for the removal of NOx from utility boiler flue gases and diesel exhausts.

Mercury speciation in the flue gas of a small-scale coal-fired boiler in Guiyang, PR China

Chemical speciation of mercury in the flue gas of a boiler with wet flue gas precipitator and desulfurization (WFGPD) system were studied by using Ontario Hydro Mercury Speciation Method. The average concentrations of Hg p , Hg 2+ , Hg 0 , and Hg t in flue gas before the WFGPD system, were 0.29 μg/m 3 , 0.64 μg/m 3 , 0.79 μg/m 3 and 1.71 μg/m 3 , respectively, and the percentage of Hg p , Hg 2+ and Hg 0 were 22.8%, 32.8% and 44.4% with regard to Hg t , respectively. However, in the flue gas after the WFGPD system, the average concentrations of Hg p , Hg 2+ , Hg 0 , and Hg t were only 0.07 μg/m 3 , 0.04 μg/m 3 , 0.58 μg/m 3 and 0.69 μg/m 3 , respectively, and the percentage of Hg p , Hg 2+ and Hg 0 with regard to Hg t were 14.3%, 8.8% and 76.9%, respectively The mean removal percentage of Hg 2+ and Hg p by the WFGPD system, concerning Hg t , was 93.8% and 74.2%. However, Hg 0 removal efficiency was only 25.8%. In the aggregate, the Hg t removal efficiency was 57.2%.

Kerr-Mcgee announces 2003 capital plan

Commercially proven technology developed by Kerr-McGee Chemical Corp., and now jointly licensed by Kerr-McGee and ABB Lummus Crest Inc., is being used for the production of food-grade and chemical-grade CO2 products from coal. The technology can also be used to recover CO2 from oil or gas-fired boiler flue gases, gas turbine and engine exhausts, and other oxygen-containing waste gases. This paper describes the Kerr-McGee/Lummus Crest appraoch for recovering CO2 from oxygen-containing gases, as well as discusses design aspects of a unit which recovers food-grade CO2 from coal-fired boiler stack gases. Markets for CO2 are also discussed.

Kerr-Mcgee announces 2003 capital plan

Commercially proven technology developed by Kerr-McGee Chemical Corp., and now jointly licensed by Kerr-McGee and ABB Lummus Crest Inc., is being used for the production of food-grade and chemical-grade CO2 products from coal. The technology can also be used to recover CO2 from oil or gas-fired boiler flue gases, gas turbine and engine exhausts, and other oxygen-containing waste gases. This paper describes the Kerr-McGee/Lummus Crest appraoch for recovering CO2 from oxygen-containing gases, as well as discusses design aspects of a unit which recovers food-grade CO2 from coal-fired boiler stack gases. Markets for CO2 are also discussed.

Injection Nozzle for Ultraviolet Light-Enhanced H2O2 Oxidation of Air Pollutants in Flue Gas

Injecting aqueous solutions of hydrogen peroxide (H2O2) into hot flue gases can split the peroxide into OH and HO2 radicals. These reactive radicals readily oxidize air pollutants such as CO, VOCs, NO, mercury, and others. H2O2 is thermally “activated” (split into free radicals) rapidly at temperatures of 500°C and above. At lower temperatures, such as found in boiler exhaust flue gases, ultraviolet (UV) light can be used to activate the peroxide molecules. However, placing the UV lamps directly in the flue gases can lead to operating and maintenance problems, and “dilutes” the UV energy due to absorption by other gases. A “UV nozzle” has been developed that produces H2O2 radicals and delivers them into a flowing stream of boiler flue gases. Using a previously constructed pilot scale system at NASA's Kennedy Space Center, experiments were run to prove the concept of the nozzle, measuring the oxidation of NO as an indicator of radical formation and delivery. Data were taken at three temperatures, with none, one, or two UV lamps on, and with various injection rates of peroxide. Flue gas temperatures ranged from 85 to 304°C (186 to 580°F), and the molar ratios (inlet peroxide to inlet NOx) ranged from about 1.5 to over 15. Conversions of NO varied from 0% (at the lowest temperature tested) to above 50% (at highest temperature). Although increasing temperature had a marked effect on conversion, the activation of hydrogen peroxide by UV light was demonstrated in the temperature range of final flue gas exhaust gases (290–350°F). These results indicate that radicals can be created from hydrogen peroxide at reasonable temperatures using UV light, and that the radicals can be delivered into a flue gas stream where they can oxidize pollutants.

Simultaneous removal of NO x and SO 2 from coal boiler flue gases by DC corona discharge ammonia radical shower systems: pilot plant tests

Pilot scale tests were conducted for simultaneous removal of NO x and SO 2 from coal boiler flue gases by corona discharge induced ammonia radical injection techniques, i.e. the corona radical shower system. Tests were conducted for the flue gas rate from 1000 to 1500 Nm 3/ h , the gas temperature from 62°C to 80°C, the ammonia-to-total acid gas molecule ratio from 0.88 to 1.3, applied voltage from 0 to 25 kV and NO initial concentration from 53 to 93 ppm for a fixed SO 2 of 800 ppm . The results show that SO 2 removal increases with increasing ammonia radical injection rate and non-monotonically depends on in-put electrical power. The NO x removal increases with increasing in-put electrical power and ammonia radical injection rate. Approximately 9 kg of SO 2 were removed by 1 kWh of energy input with 99% of SO 2 removal, while approximately 125 g of NO x was removed by 1 kWh of energy input with 75% of removal efficiency.

KERR-MCGEE SANCTIONS DEEPWATER GAS DEVELOPMENT

Commercially proven technology developed by Kerr-McGee Chemical Corp., and now jointly licensed by Kerr-McGee and ABB Lummus Crest Inc., is being used for the production of food-grade and chemical-grade CO2 products from coal. The technology can also be used to recover CO2 from oil or gas-fired boiler flue gases, gas turbine and engine exhausts, and other oxygen-containing waste gases. This paper describes the Kerr-McGee/Lummus Crest appraoch for recovering CO2 from oxygen-containing gases, as well as discusses design aspects of a unit which recovers food-grade CO2 from coal-fired boiler stack gases. Markets for CO2 are also discussed.

Boiler flue gas desulfurization system

The development of materials with large nonlinear response and ultra-fast response is the goal of the field of nonlinear optics. Here, we report the large nonlinear response (Imχ(3)=-8.54 × 10−11 esu; FOM = 4.03 × 10−11 esu cm) and femtosecond timescale carrier recovery time in few-layer germanium sulfide (GeS) with high crystal quality. The GeS exhibited a broad-band nonlinear optical absorption (400−800 nm) and large nonlinear optical response which is wavelength and excitation intensity dependent. The saturable absorption response with short wavelength excitation is stronger than that of the other two long excitation wavelengths. The carrier recovery times of the few layer GeS were determined to be hundreds of femtoseconds. Our results indicated that the few layer GeS is a promising candidate for the nanophotonic applications such as saturable absorber and optical diode.

101 潜熱回収によるボイラ効率の向上(FM-1 ガスタービン以外の熱機関の性能向上(1))

Nowadays, reduction of CO_2 emissions is one of the most important problem in Japanese industry with respect to global warming. The improvement of boiler efficiency is the most effective for reduction of CO_2 emissions in industry boiler field compared with other CO_2 reduction technologies. The heat loss by flue gas is the major part in the total heat loss of the boiler. The natural gas has increased to be used for small boilers recently. It is easy to recover waste heat from flue gas of boiler. It contains about 15 vol. % of H_2O gas in flue gas of natural gas-fired boiler. So, we can get substantial improvement in boiler efficiency by recovering not only the sensible heat, but also the latent heat from the flue gas.

Commercial Boiler Waste-Heat Utilization for Air Conditioning in Developing Countries

This study investigates the utilization of waste heat from commercial process steam boilers for air conditioning using absorption cooling systems. An ammonia-water generator absorber heat exchange system was developed and modeled to use waste heat from the boiler flue gases and deliver chilled water. Based on approximately 1000 process steam boilers at an average throughput of 2000 kg/h in one metropolitan area in India, the study estimates that installation of these systems could result in annual operating cost savings of $10,200,000 in this region alone. These 1000 systems would also reduce the installed electric capacity needs by 16 MW. Annual coal consumption would decrease by 87,000 tonnes, while ash production would decrease by 39,000 tonnes. Carbon-based emissions are estimated to decrease by 176,000 tonnes. Therefore, installation of these systems on a countrywide basis and also in other developing countries with high year-round cooling loads and coal-based power generation would significantly alleviate installed power capacity shortages, conserve energy resources, and reduce greenhouse gas emissions.

99/01405 Condensing economizers for efficiency improvement and emissions control in industrial boilers : Butcher, T. A. et al. Combust. Can. 1996 Conf.: Future Changing Role Combust. Can. Effic. Environ., 1996, Paper7/1–7/15

Condensing economizers recover sensible and latent heat from boiler flue gas, leading to marked improvements in thermal efficiency. This paper summarizes the current commercial status and continuing development efforts with one type of condensing economizer. In this design Teflon{reg_sign} covered tubes and enclosure walls are used to handle the corrosive condensate. Flue gas flows around the tubes and feed water, being heated, flows through the inside. In addition to improving thermal efficiency, condensing economizers can also be used to reduce particulate emissions primarily by inertial impaction of particles on tube surfaces, water droplets, and added impactors. Collected particles are then removed with condensate. Water sprays directly on the tubes can be used to enhance particle capture. With coal-firing, tests have shown particle removal efficiencies as high as 98%. To enhance the emissions control potential of condensing economizer technology a two-stage economizer system concept has been developed. Two heat exchanger modules are used. The first is a downflow design and recovers primarily sensible heat from the flue gas. The second is upflow and recovers mostly latent heat. Condensate is collected in a transition plenum between the two stages. This configuration, termed the Integrated Flue Gas Treatment System, provides great flexibility for implementing emissions reduction strategies. Particulate emissions can be reduced without impacting sensible heat recovery by recirculating collected condensate to spray nozzles at the top of the second stage heat exchanger. In tests at BNL with heavy oil firing, particulate reductions over 90% and final emission rates on the order of.005 lb/MMBtu are achieved. Adding sorbents to the recirculated condensate reduces sulfur dioxide emissions and SO{sub 2} removal efficiencies over 95% are achieved. Also, condensing economizers show great potential for the removal of certain air toxics such as mercury and nickel.

98/04314 Recent developments in coal mine inertisation in Australia

98/04314 Recent developments in coal mine inertisation in Australia

Carbon Dioxode Recovery: Large Scale Design Trends

Abstract With renewed interest in enhanced oil recovery (EOR) as existing fields become depleted, there is renewed interest in supplying CO2 for flooding by CO2 recovery from flue gas. This paper examines key design and operating issues and trends for new unit designs which hold the potential for reducing the plant investment and operating costs associated with this source of CO2. The emphasis is on conventional processes using chemical solvents for CO2 removal (such as Fluor Daniel's ECONAMINE FGSM process) as these are either commercial or have been successfully pilot tested. Developments in new tower packings and solvents and their potential impact on plant and operating costs are discussed, as are the effects on these costs of the flue gas source. Operating and capital recovery cost data are provided for 1,000 tonne/d plants which would be a typical size for an EOR project. Introduction In the mid 1980s, when crude oil prices were over $30 per barrel, several plants came on line in West Texas in the U.S. which used 30 wt% MEA with special inhibitors to extract CO2 from boiler flue gas for use in EOR. However, when the price of crude oil dropped dramatically, these plants quickly became uneconomic and were scrapped. The then existing process licensors, Dow Chemical and Union Carbide, became less active in promoting these technologies and in 1989 Dow Chemical sold their FT-1 process to Fluor Daniel Inc. Fluor renamed the technology "ECONAMINE FG" and has since licensed three commercial plants, one 320 tonne/d plant at Bellingham, Massachusetts, U.S.A. (1989), a 150 tonne/d plant for Sumitomo Chemical at Chiba, Japan (1993) and a 90 tonne/d plant for Prosint Produtos Sint?ticos at Rio de Janeiro, Brazil (1997). All plants sell CO2 primarily to the food industry. The Bellingham plant, which has a gas turbine exhaust flue gas source, was constructed by Fluor. The Sumitomo plant was constructed by Mitsubishi Heavy Industries (MHI) with the flue gas source from a boiler fired by a variety of fuels including heavy fuel oils. The Prosint plant was owner-constructed and has a boiler flue gas feed source. In addition, Fluor has performed a number of studies, several of which involved large-scale plants (1,000 tonne/d and larger). These studies were prompted by interest in using the CO2 for EOR and to avoid the new carbon tax being imposed in EC countries. In addition, the company designed two pilot plants for Japan which were used by the owners to study the process for greenhouse gas mitigation purposes. The results from the KEPCO pilot plant have been reported in the literature(1,2). Much of the KEPCO work is applicable to EOR applications as will be discussed later in this paper. Interest in greenhouse gas emission mitigation has spawned a number of processes for capturing CO2 from boiler stacks that differ considerably from capture by chemical solvents. None of these processes are presently offered commercially and most will remain in the laboratory study phase at least for the near future.

98/02257 Purification of coal fired boiler flue gas and fertilizer production by using electron beam

The partitioning of iron during pulverized coal combustion was investigated both experimentally and theoretically. Emphasis was on determining how coal variables and combustion conditions influenced the formation of slagging precursors. Experimental work consisted of burning a suite of six well-characterized coals in an aerodynamically well-defined 17 kW downflow combustor. Speciation of iron in collected ash samples was determined by Mössbauer Spectroscopy. A model was developed to predict the partitioning of iron for the coals and experimental conditions examined. The model was based on a competition between pyrite oxidation and iron capture by silicates and required as input, CCSEM data on the initial distribution of mineral matter in the coal. It used literature-derived mechanisms and kinetics to calculate pyrite oxidation and char combustion rates, together with a new glass formation mechanism, coupled with current knowledge of sintering. Requiring only two unknown parameters to be fitted, the model agreed well with 26 sets of experimental data, which covered a wide range of iron partitioning in the fly ash. Both experimental and theoretical results suggest that removal from the parent coal, of extraneous iron alone, may not be very effective in eliminating slag formation in boilers.

98/02237 Apparatus for dust-charged wet-type desulfurization of coal-fired boiler flue gases

98/02237 Apparatus for dust-charged wet-type desulfurization of coal-fired boiler flue gases

97/04145 Boiler flue gas cleaning by condensation and liquefaction

97/04145 Boiler flue gas cleaning by condensation and liquefaction