Power Plant Stack Gases Research Articles

Equilibrium solubility of CO2 in aqueous binary mixture of 2-(diethylamine)ethanol and 1, 6-hexamethyldiamine

CO2 solubility data are important for the efficient design and operation of the acid gas CO2 capture process using aqueous amine mixture. 2-(Diethylamino)ethanol (DEEA) solvent can be manufactured from renewable sources like agricultural products/residue, and 1,6-hexamethyldiamine (HMDA) solvents have higher absorption capacity as well as reaction rate with CO2 than conventional amine-based solvents. The equilibrium solubility of CO2 into aqueous binary mixture of DEEA and HMDA was investigated in the temperature range of 303.13-333.13 K and inlet CO2 partial pressure in the range of 10.133-20.265 kPa. Total concentration of aqueous amine mixtures in the range of 1.0-3.0 kmol/m3 and mole fraction of HMDA in total amine mixture in the range of 0.05-0.20 were taken in this work. CO2 absorption experiment was performed using semi-batch operated laboratory scale bubble column to measure equilibrium solubility of CO2 in amine mixture, and CO2 absorbed amount in saturated carbonated amine mixture was analyzed by precipitation-titration method using BaCl2. Maximum equilibrium CO2 solubility in aqueous amine mixture was observed at 0.2 of HMDA mole fraction in total amine mixture with 1.0 kmol/m3 total amine concentration. New solubility data of CO2 in DEEA+HMDA aqueous mixtures in the current study was compared with solubility data available in previous studies conducted by various researchers. The study shows that the new absorbent as a mixture of DEEA+HMDA is feasible for CO2 removal from coal-fired power plant stack gas streams.

Experimental scale multi component absorption of SO2 and NO by NH3/NaClO scrubbing

In current situation numerous technologies have been applied for simultaneous removal of SO2 and NO in coal fired power plant stack gases, one of the major SO2 and NO emission sources. But few researches had been done concentrating in environmental aspect for simultaneous SO2 and NO absorption. No established technology was opted for removal of these toxic gases suitable for coal fired thermal power plants. This paper suggests a proposed feasible method for instantaneous removal of SO2 and NO by NH3/NaClO scrubbing. The main intention for the development of this process is to produce valuable products such as ammonium sulphite, ammonium nitrite, ammonium sulphate and ammonium nitrate which can be utilized as fertilizer for plants in agricultural field. Here NaClO can be utilized as oxidative additive in the aqueous absorbent blend of NH3/NaClO to make the process of simultaneous removal of SO2 and NO by wet scrubbing feasible. The experimental parameters such as reaction temperature, mole ratio of NH3 to NaClO, reaction time, SO2 concentration, NO concentration, etc. were studied in this process. The optimal operating parameters were determined. The detailed process description has been explained in this paper.

Reactive absorption of NO and SO2 into aqueous NaClO in a counter‐current spray column

AbstractThe experiments were performed in a spray column to study the simultaneous absorption of NO and SO2 using NaClO solution from simulated gas stream under various experimental conditions. The effects of various influencing parameters, such as absorbent concentration, reaction temperature, initial SO2 and NO concentration, and initial pH of NaClO solution on simultaneous removal of SO2 and NO, were emphatically investigated in regard to coal‐fired thermal power plant stack gas emission control. The maximum removal efficiencies of SO2 and NO were found as 97% and 87.8%, respectively, at 313 K, initial NaClO solution pH 5.4 and 0.024 M NaClO concentration. The addition of CO2 in simulated gas stream was also carried out to see its influence on removal efficiency of SO2 and NO. The results using a spray column showed that NaClO can be used effectively for simultaneous removal of NO and SO2from coal‐fired thermal power plant simulated gas stream. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

화력발전소 배출가스 중 질소산화물의 확산에 관한 연구

화력발전소 배출가스 중 질소산화물의 확산에 관한 연구

New experimental results of combined SO2 and NO removal from simulated gas stream by NaClO as low-cost absorbent

The experiments were performed in a magnetic stirrer reactor to study the simultaneous absorption of NO and SO2 using NaClO solution from simulated gas stream. The effects of various operating parameters viz., absorbent concentration, reaction temperature, initial SO2 and NO concentration and initial pH of NaClO solution on simultaneous removal of SO2 and NO were investigated in regard to coal-fired thermal power plant stack gases. The maximum removal efficiencies of SO2 and NO were observed as 100% and 92%, respectively at 313K, initial NaClO solution pH 5.8 and 0.01M NaClO concentration. The important rate governing steps with appropriate reaction mechanisms for simultaneous removal of SO2 and NO using NaClO as absorbent were also discussed.

Solubility of CO2 in aqueous strontium hydroxide

The present communication represents the experimental results on CO2 solubility in aqueous Sr(OH)2 as an innovative absorbent. The absorption experiments were carried out over the temperature range of 303.14–333.14K and CO2 inlet partial pressure range of 10.133–20.265kPa in the light of coal-fired thermal power plant stack gases using a bubble column. The concentration of Sr(OH)2 was varied from 12.548 to 26.08g Sr(OH)2/100g water. All parameters viz., CO2 inlet partial pressure, temperature and the absorbent concentration showed positive effects on CO2 solubility. The CO2 absorption in aqueous Sr(OH)2 was found to follow first order rate kinetics. The results showed that Sr(OH)2 can be an efficient absorbent for removal of CO2 due to the formation of useful product SrCO3 after absorption.

Atmospheric distribution of organic compounds from urban areas near a coal-fired power station

Atmospheric particulate matter and volatile organic compounds (VOCs) from three sites surrounding a thermoelectric complex, VOCs from the power plant stack gas and aliphatic and aromatic fractions obtained from a coal sample utilized by the thermoelectric complex were monitored in Tubarao and Capivari de Baixo cities, State of Santa Catarina, Brazil, in December 1997. Literature data were reviewed in order to outline differences and similarities among sources and levels of pollutants from coal combustion. Concentrations of benzo[a]pyrene, which is a well-known carcinogenic chemical, were relatively high compared to large urban agglomerations worldwide and similar compared to Asian cities as Beijing in China, a substantial producer and consumer of coal. Concentrations of benzene were lower than other Brazilian urban areas. Quantitation of the compounds identified showed that they were present within the recommended limits of exposure for substances present in air.

Fossil fuel decarbonization technology for mitigating global warming

It has been understood that production of hydrogen from fossil and carbonaceous fuels with reduced CO 2 emission to the atmosphere is key to the production of hydrogen-rich fuels for mitigating the CO 2 greenhouse gas climate change problem. The conventional methods of hydrogen production from fossil fuels (coal, oil, gas and biomass) include steam reforming and water gas shift mainly of natural gas (SRM). In order to suppress CO 2 emission from the steam reforming process, CO 2 must be concentrated and sequestered either in or under the ocean or in or underground (in aquifers, or depleted oil or gas wells). Up to about 40% of the energy is lost in this process. An alternative process is the pyrolysis or the thermal decomposition of methane, natural gas (TDM) to hydrogen and carbon. The carbon can either be sequestered or sold on the market as a materials commodity or used as a fuel at a later date under less severe CO 2 restraints. The energy sequestered in the carbon amounts to about 42% of the energy in the natural gas resource which is stored and not destroyed. A comparison is made between the well developed conventional SRM and the less developed TDM process including technological status, efficiency, carbon management and cost. The TDM process appears to have advantages over the well developed SRM process. It is much easier to sequester carbon as a stable solid than CO 2 as a reactive gas or low temperature liquid. It is also possible to reduce cost by marketing the carbon as a filler or construction material. The potential benefits of the TDM process justifies its further efficient development. The hydrogen can be used as a transportation fuel or converted to methanol by reaction with CO 2 from fossil fuel fired power plant stack gases, thus allowing reuse of the carbon in conventional IC automobile engines or in advanced fuel cell vehicles.

Production of hydrogen and methanol from natural gas with reduced CO 2 emission

The thermal decomposition of natural gas forms the basis for the production of hydrogen with reduced CO 2 emission. The hydrogen can be used to reduce CO 2 from coal-fired power plants to produce methanol which can be used as an efficient automotive fuel. The kinetics of methane decomposition is studied in a one inch diameter tubular reactor at temperatures between 700 and 900 °C and at pressures between 28 and 56 atm. The Arrhenius activation energy is found to be 31.3kcal/mol of CH 4. The rate increases with higher pressures and appears to be catalyzed by the presence of carbon particles formed. The conversion increases with temperature and is equilibrium limited. A thermodynamic study indicates that hydrogen produced by methane decomposition while sequestering the carbon produced requires the least amount of process energy with zero CO 2 emission. Application to methanol synthesis by reacting the hydrogen with CO 2 recovered from coal burning power plant stack gases can significantly reduce CO 2 from both the utility and transportation sectors. Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy.

The Carnol process for CO 2 mitigation from power plants and the transportation sector

A CO 2 mitigation process is developed which converts waste CO 2, primarily recovered from coal-fired power plant stack gases with natural gas, to produce methanol as a liquid fuel and coproduct carbon as a materials commodity. The Carnol process chemistry consists of methane decomposition to produce hydrogen which is catalytically reacted with the recovered waste CO 2 to produce methanol. The carbon is either stored or sold as a materials commodity. A process design is modelled and mass and energy balances are presented as a function of reactor pressure and temperature conditions. The Carnol process is a viable alternative to sequestering CO 2 in the ocean for purposes of reducing CO 2 emissions from coal burning power plants. Over 90% of the CO 2 from the coal burning plant is used in the process which results in a net CO 2 emission reduction of over 90% compared to that obtained for conventional methanol production by steam reforming of methane. Methanol as an alternative liquid fuel for automotive engines and for fuel cells achieves additional CO 2 emission reduction benefits. The economics of the process is greatly enhanced when carbon can be sold as a materials commodity. Improvement in process design and economics should be achieved by developing a molten metal (tin) methane decomposition reactor and a liquid phase, slurry catalyst, methanol synthesis reactor directly using the solvent saturated with CO 2 scrubbed from the power plant stack gases. The benefits of the process warrants its further development.

The Carnol process for CO2 mitigation from power plants and the transportation sector

Abstract A CO2 mitigation process is developed which converts waste CO2, primarily recovered from coal-fired power plant stack gases with natural gas, to produce methanol as a liquid fuel and coproduct carbon as a materials commodity. The Carnol process chemistry consists of methane decomposition to produce hydrogen which is catalytically reacted with the recovered waste CO2 to produce methanol. The carbon is either stored or sold as a materials commodity. A process design is modelled and mass and energy balances are presented as a function of reactor pressure and temperature conditions. The Carnol process is a viable alternative to sequestering CO2 in the ocean for purposes of reducing CO2 emissions from coal burning power plants. Over 90% of the CO2 from the coal burning plant is used in the process which results in a net CO2 emission reduction of over 90% compared to that obtained for conventional methanol production by steam reforming of methane. Methanol as an alternative liquid fuel for automotive engines and for fuel cells achieves additional CO2 emission reduction benefits. The economics of the process is greatly enhanced when carbon can be sold as a materials commodity. Improvement in process design and economics should be achieved by developing a molten metal (tin) methane decomposition reactor and a liquid phase, slurry catalyst, methanol synthesis reactor directly using the solvent saturated with CO2 scrubbed from the power plant stack gases. The benefits of the process warrants its further development.

Design of monolith catalysts for power plant nitrogen oxide (No.+-.) emission control

A mathematical model was developed to describe the reduction of NO with NH 3 in simulated power plant stack gases, over the internal surfaces of monolith-shaped catalysts of the vanadia-titania type. The model indicated that up to 50% improvement in the volumetric activity of these catalysts would be possible if they could be prepared with the computed optimum pore structure

A study of the energetics and economics of microalgal mass culture with the marine chlorophyte Tetraselmis suecica: Implications for use of power plant stack gases

The marine phytoplankter Tetraselmis suecica was grown in shallow outdoor flumes for a period of approximately 6 months at the Natural Energy Laboratory of Hawaii. In full sunlight, gross production rates were 15-20 g C m(-2) d(-1). The corresponding photosynthetic efficiencies (PE's) were 9-10%. Respiration losses removed about half the gross production. The CO(2) utilization efficiencies of 96 +/- 11% were achieved by bubbling CO(2) into the culture with the use of a counterflow sump system. Adding the CO(2) in the form of carbonated water resulted in utilization efficiencies of 81 +/- 11%. Archimedes screws proved superior to both paddle wheels and propellers as a means of circulating the water in the flumes. Insertion of foil arrays into the flumes to effect systematic mixing of the culture significantly enhanced production. The enhancement was greater when the foils were oriented at a small angle relative to the horizontal than when they were oriented at the same angle relative to the vertical. Light modulation effects are implicated as the probable cause of most of the enhancement. Substitution of electric power plant stack gases for pure CO(2) resulted in no significant change in the production of T. suecica grown in chemostat culture.

Primary Sulfates in Atmospheric Sulfates: Estimation by Oxygen Isotope Ratio Measurements

The relative amounts of primary and secondary sulfates in atmospheric aerosols and precipitation can be estimated from measurements of the stable oxygen isotope ratios. The oxygen-18 content of sulfates formed in power plant stack gases before emission into the atmosphere is significantly higher than that of sulfates formed from sulfur dioxide after emission. Results show that 20 to 30 percent of the sulfates in rain and snow at Argonne, Illinois, are of primary origin.

Coal gasification: a source of carbon dioxide for enhanced oil recovery?

A preliminary analysis of how the concentrated carbon dioxide stream produced by the high-Btu coal gasification process might be used for enhanced oil recovery is presented. Because power plant stack gases are not amenable to CO/sub 2/ recovery and utilization, this concept offers synfuel production a significant advantage over coal electrification by minimizing CO/sub 2/ emissions to the atmosphere. (JMT)

Sheep Mountain CO2 Production Facilities - A Conceptual Design

This paper discusses the potential supply of CO2 for enhanced recovery projects from the natural CO2 reservoir at Sheep Mountain, Huerfano projects from the natural CO2 reservoir at Sheep Mountain, Huerfano County, CO. Producing well characteristics are examined, and a conceptual process is discussed for separation of water, dehydration, compression, and transportation of 300 MMscf/D of CO2 from Colorado to Texas. Introduction Carbon dioxide (CO2) enhanced recovery projects potentially could recover up to 40% of all oil produced by potentially could recover up to 40% of all oil produced by enhanced recovery methods. CO2 supply is a critical factor in the ability to undertake the scope of available projects. The major sources of supply include power projects. The major sources of supply include power plant stack gas, future coal gasification plants, and plant stack gas, future coal gasification plants, and natural deposits. Although power and coal gasification plants eventually may be important sources, natural plants eventually may be important sources, natural deposits likely will be the first source to be developed.ARCO Oil and Gas Co. began studies of a natural CO2 reservoir at Sheep Mountain in Huerfano County, CO, in 1972. These studies resulted in lease of private, state, and federal lands and the formation of two development units, Sheep Mountain Unit and Dike Mountain Unit (Fig. 1). Sixteen wells within these units have delineated a deposit of sufficient size to warrant a pipeline study. Given sufficient incentive for enhanced oil recovery, ARCO Oil and Gas Co. could build a 20-in. pipeline 420 miles to the Permian basin to deliver 300 MMscf/D. The proposed route shown in Fig. 2 terminates at the Wasson (San Andres) and Seminole (San Andres) fields located in Yoakum and Gaines counties, TX. Pipeline Pipeline The pipeline would begin in the northwestern portion of Sheep Mountain Unit at an elevation of 8,000 ft and continue southeast near Trinidad, CO, where it would drop to an elevation of 5,400 ft. The line would climb to an elevation of 8,250 ft east of Raton Pass before continuing southeastward across New Mexico and into Texas to the Seminole field at an elevation of 3,400 ft.The pipeline would operate as a liquid-filled system requiring sufficient pressure throughout the line to prevent two-phase (gas/liquid) occurrence and an input prevent two-phase (gas/liquid) occurrence and an input pressure exceeding 1,200 psig. CO2 density at various pressure exceeding 1,200 psig. CO2 density at various pipeline operating conditions can vary from 44 to almost pipeline operating conditions can vary from 44 to almost 60 lbm/cu ft; therefore, the differences in elevation involve significant head changes. Two-phase conditions would be approached at the maximum design rate of 300 MMscf/D where the line rises to 8,250 ft, resulting in the lowest line pressure of approximately 950 psig. Two-phase conditions would be approached more closely in late summer as the flowing temperature peaks, perhaps approaching 75 degrees F. The 8,250-ft location also would be critical to winter operating conditions because of the reduced ability of the CO2 to hold water at low temperature and pressure. One criterion for pipeline corrosion control is for the CO2 to have a water content less than 60% of saturation. Thus, the 8,250-ft elevation mountain crossing establishes the required input line pressure and the degree of dehydration required of the producing equipment.Desired pipeline delivery pressure is approximately 2,000 psig, which is sufficient for field distribution and injection control. The pipeline is sized to facilitate this delivery pressure at 300 MMscf/D without booster compression along the line. JPT P. 1462

Membrane electrodialysis process for recovery of sulfur dioxide from power plant stack gases

A new regenerative process for recovery of sulfur dioxide from stack gases by sodiumbased solution scrubbing is described. The spent solution from the scrubber, consisting mostly of bisulfite, is converted through the use of a novel low-energy membrane electrodialysis technique to a basic solution of sulfite/hydroxide suitable for reuse in the SO 2 absorbers, and a solution of sulfurous acid from which concentrated SO 2 is easily regenerated. p]This electrodialysis process, based on bipolar membrane technology, requires only a fraction of the energy required in conventional electrolysis. Engineering estimates indicate that this membrane/SO 2 process has a significant economical advantage over other gas desulfurization processes. In addition, this process has internal flexibility to operate under various conditions without the requirement of significant equipment modification.

Improving mass transfer characteristics of limestone slurries by use of magnesium sulfate

Poor mass transfer coefficients for limestone scrubbing slurries limit the effectiveness of spray-type scrubbers in removing SO/sub 2/ from power plant stack gases. Large resistances in the liquid phase, due to the need for limestone or calcium sulfite to dissolve during the absorption process, are the cause of this inefficiency. Experimental work is presented to show that these resistances can be largely eliminated by addition of magnesium sulfate to the slurry, enabling an efficiency to be achieved that approaches that of strong sodium carbonate solution. A detailed description of the chemical processes involved is given, accompanied by experimental data showing the effect of sulfate addition on the dissolved scrubbing capacity of the slurries. The magnesium sulfite ion pair, MgSO/sub 3//sup 0/, is shown to be responsible for the increased scrubbing efficiency. As a bonus, it was found that slurries containing magnesium sulfate could be treated with air to convert sulfite sludge into filterable gypsum.

Reduction of Nitric Oxide with Ammonia on Noble Metal Catalysts

The reduction of nitric oxide with ammonia on alumina-supported platinum, palladium, ruthenium, and rhodium catalysts was studied in flow reactors at temperatures between 120 and 400/sup 0/C. The presence of oxygen in the gas mixture enhanced the reduction of NO on Pt and Pd below about 230/sup 0/C, whereas O/sub 2/ inhibited NO reduction on Ru and Rh. Considerable nitrous oxide was produced on both Pt and Pd in the presence of O/sub 2/. Using a simulated power plant stack gas containing 14% carbon dioxide, 5% water, 3% O/sub 2/, and 250 to 1000 ppM NO, the conversion of NO was a function of the NH/sub 3//NO inlet ratio from 0.5 to 2.3. The presence of O/sub 2/ also accelerated the decomposition of NO on Pt in the simulated flue gas. Maximum decomposition occurred with 2% O/sub 2/ present in the flue gas at a temperature of 300/sup 0/C.

Reduction and removal of SO2 and NOx from simulated flue gas using iron oxide as catalyst/absorbent

AbstractIron oxide supported on alumina is a promising catalyst/absorbent for use in the simultaneous removal of NOx and SOx from power plant stack gases. A dry‐contacting process is under development which would operate under net reducing conditions at temperatures of 370° to 540°C. Iron oxide is converted to the ferrous state, NO is reduced to N2 or NH3, and SO2 is removed as ferrous sulfide or sulfate. Regeneration with air produces SO2 and reforms Fe2O3.The reduction of SO2 by CO and H2 was studied in fixed‐bed reactors to determine the effects of temperature and of the other reactive components of flue gas (excepting fly ash) on the rate of reaction and the products formed. H2S and COS react with FeO to form FeS. Under readily attainable conditions, virtually complete removal of sulfur compounds was achieved for gas‐phase residence times of about 1 to 10 ms. NO and O2 were also reduced. Conditions under which oxygen poisons the catalyst were determined.