Reburning of Cattle Manure-Based Biomass With Coals in a Small Scale Boiler Burner Facility for NOx and Hg Reduction

2011 ◽  
Author(s):  
Hyukjin Oh ◽  
Kalyan Annamalai ◽  
John Sweeten
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Molecular Nitrogen ◽  
Pulverized Coal ◽  
Cattle Manure ◽  
Solid Fuels ◽  
Small Scale ◽  
Fixed Carbon ◽  
Boiler Burner ◽  
Conversion Technologies

Reburning of cattle manure-based biomass (CB) with coals is performed to develop environmentally friendly thermo-chemical energy conversion technologies for NOx reductions and Hg captures and removals from existing pulverized coal-fired power plants. A small-scale (30 kWth) down-fired boiler burner facility has been used for burning most types of pulverized solid fuels including coal and biomass. Blends of CB and coals are used as reburn fuels. It has hypothesized that a major fraction of the fuel-N in the CB is released in the form of NH3 or urea. In the reburn process, therefore, it is believed that NOx produced by coal is reduced to molecular nitrogen by NH3 released from the pyrolysis of CB under slightly fuel-rich conditions. The CB also contains larger amounts of chlorine (Cl) than most types of coals. Hence gaseous mercury (Hg) in the flue gas is oxidized by large amounts of Cl species mainly from the CB combustion. Consequently, the results indicate that the CB can serve as a very effective fuel supplementing coals on NOx reductions and Hg captures and removals in pulverized coal-fired boilers. It was also found that the auto-gasification occurred during the pyrolysis due to the oxygen available in the fuel mainly helped for burning fixed carbon.

Combustion of Cattle Biomass as a Supplementary Fuel in a Small Scale Boiler Burner Facility for NOx and Mercury Reductions

2009 ◽  
Author(s):  
Hyukjin Oh ◽  
Kalyan Annamalai ◽  
John M. Sweeten ◽  
Christopher Rynio ◽  
Witold Arnold
Keyword(s):  
Power Plants ◽  
Unburned Carbon ◽  
Small Scale ◽  
Large Animal ◽  
Stoichiometric Ratio ◽  
Coal Consumption ◽  
Animal Feeding Operations ◽  
Boiler Burner ◽  
Conversion Technologies ◽  
Fuel Costs

Combustion of cattle biomass (CB) as a supplementary fuel has been proposed for reducing emissions of NOx, Hg, SO2, and nonrenewable CO2 in large coal-fired power plants. It has benefits to power industries for lowering coal consumption and fuel costs and to animal industries for disposing burdensome agricultural wastes from large animal feeding operations. In order to develop environmentally friendly thermo-chemical energy conversion technologies that can utilize CB for NOx and Hg reductions in existing coal-fired power plants, co-firing and reburning experiments involving CB and coal were performed in a small-scale 30 kWt (100,000 Btu/h) downward fired boiler burner facility. The co-firing results are mainly presented and discussed. Preliminary reburn results are also reported. The results show that the pulverized CB can serve as a supplementary fuel for the coal-fired boilers, and combustion of the CB with coals shows reductions in NOx and Hg emissions. It is believed that 1) most of the fuel-nitrogen in the CB existed in forms of NH3 or urea which led the high NOx reductions and 2) burning the CB containing high chlorine (Cl) produced large amounts of Cl species (mainly HCl) which oxidized the elemental Hg in the flue gas, hence the Hg emissions were reduced. The equivalence ratio (φ), an inverse value of the stoichiometric ratio, was considered as a key parameter to achieve high NOx reductions. Higher NOx and Hg reductions were measured under fuel-rich conditions (φ > 1.0). It appeared that the effect of the unburned carbon (UBC) was much stronger on the Hg reductions than that of Cl.

Theoretical and Experimental Evaluation of the EvGT-Process

2000 ◽  
Author(s):  
Torbjörn O. Lindquist ◽  
Per M. Rosén ◽  
Tord Torisson
Keyword(s):  
Gas Turbine ◽  
Flue Gas ◽  
Power Output ◽  
Pilot Plant ◽  
Power Plants ◽  
Saturation Temperature ◽  
Combined Cycle ◽  
Small Scale ◽  
Pinch Point ◽  
Gas Turbine Cycle

Abstract In recent years the interest for new advanced thermodynamical gas turbine cycles has increased. One of the new designs is the evaporative gas turbine cycle. A lot of effort worldwide has been put into predicting the possible efficiency, pollutants, and dynamic behaviour of the evaporative gas turbine cycle, but all results so far have been affected by uncertain assumptions. Until now this cycle has not been demonstrated in a pilot plant. The purpose of this work has been to identify the potential of this cycle, by erecting a pilot plant at the Lund Institute of Technology. The project was financed on a 50/50 basis from the Swedish National Energy Administration and the industrial partners. Three different thermodynamical cycles have been tested in the pilot plant: the simple, the recuperative, and the evaporative cycles. The final pilot plant roughly consists of a 600 kW gas turbine, a hydraulic brake, a recuperator, a humidification tower, an economiser, and a flue gas condenser. All layout and functional analysis were made within the project. The pilot plant is, however, optimized neither for best efficiency nor for best emissions. It has only been built for demonstration purpose. It has been shown from the performance tests that the efficiency for the simple, recuperative, and evaporative cycles are 22, 27, and 35%, respectively, at rated power output. The NOx emissions were reduced by 90% to under 10 ppm, and the UHC and CO were not measurable when running the evaporative cycle at rated power output. The performance of the humidification tower was better than expected. The humidified air out from the humidification tower is always saturated. The pinch point, i.e. the temperature difference between the outcoming water from the humidification tower and the saturation temperature of the incoming air, is around 3°C. The water circuit was closed, i.e. there was no need for additional water, when the flue gases after the flue gas condenser reached a temperature of 35° C. The inhouse heat balance program, used for both cycle optimization and evaluation, has been verified. The evaporative gas turbine cycle has, when optimized, at least the same efficiency as the best combined cycle today, based on the same gas turbine. The evaporative cycle will also show very good performance when used in small scale power plants.

Design and Computational Validation of In-Line Bare Tube Economizer for a 210 MW Pulverized Coal Fired Boiler

2013 ◽  
Author(s):  
P. R. Dhamangaonkar ◽  
Abhishek Deshmukh ◽  
Santosh Pansare ◽  
M. R. Nandgaonkar
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Power Plants ◽  
Gas Flow ◽  
Tube Bundle ◽  
Thermal Power ◽  
Pulverized Coal ◽  
Root Cause ◽  
Economizer Tube ◽  
Bare Tube

One of the pulverized coal fired thermal power plants in India intended to find the root cause of frequent boiler tube failures in three 210 MW units. Operation & Maintenance history and feedback from plant O&M team revealed that economizer tube failure was a frequent cause of forced outage. The plant under study used CFS (continuous fin surface) economizer with staggered tube arrangement in the 210 MW units. CFS staggered tube economizers originally appealed to many plant designers because the tortuous path created for the flue gas, enhanced heat absorption and the fins could capture heat and transfer it to the tubing. This made the CFS economizer less costly and easy for installation in a relatively small space. There is increasing use of lower quality high ash coals over the past few decades. Due to this fact an advantage of the CFS economizer design became a disadvantage. The narrow spacing in the tubes proved more susceptible to plugging and fly ash erosion. Literature study and the root cause analysis suggested that CFS staggered arrangement of economizer could be one of the prominent reason of failure of economizer tube bundle due to fly ash erosion. Flue gas flow simulation also highlighted that there is increase in velocity of flue gases across the economizer. A bare tube in-line configuration in place of existing CFS economizer was an alternative. To recommend an alternate economizer as solution, the merits of an in-line bare tube economizer were studied. Bare tubes arranged in-line are most conservative in hostile environments with high ash content, are least likely to plug, and have the lowest gas-side resistance per unit of heat transfer. A bare tube in-line economizer that can replace the existing finned tube economizer in the available space while meeting the existing design & performance parameters is recommended. An attempt was made to model & analyze the new economizer using computational fluid dynamics (CFD) tools in order to get firsthand experience and validate the results obtained using manual calculations. With limited computational resources and not so fine meshing, the performed CFD model analysis showed the expected trend but did not completely match the results.

Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Superheated Steam ◽  
Black Liquor ◽  
Simulation Software ◽  
Operating Conditions ◽  
Costs And Benefits ◽  
Steam Generation ◽  
Fireside Corrosion ◽  
Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

On the prospect of introduction of plasma ignition in power boilers

2019 ◽  
Vol 12 (1) ◽  
pp. 22-28
Author(s):  
V. Ye. Mikhailov ◽  
S. P. Kolpakov ◽  
L. A. Khomenok ◽  
N. S. Shestakov
Keyword(s):  
Russian Federation ◽  
Solid Fuel ◽  
Power Plants ◽  
Thermal Power ◽  
Fuel Oil ◽  
Solid Fuels ◽  
Thermal Power Plants ◽  
Plasma Ignition ◽  
The Russian Federation ◽  
Capital Construction

One of the most important issues for modern domestic power industry is the creation and further widespread introduction of solid propellant energy units for super-critical steam parameters with high efficiency (43–46%) and improved environmental parameters. This will significantly reduce the use of natural gas.At the same time, one of the major drawbacks of the operation of pulverized coal power units is the need to use a significant amount of fuel oil during start-up and shutdown of boilers to stabilize the burning of the coal torch in the variable boiler operating modes.In this regard, solid fuel TPPs need to be provided with fuel oil facilities, with all the associated problems to ensure the performance (heating of fuel oil in winter), reliability and safety. All of the above problems increase both the TPP capital construction costs, and the electricity generating cost.A practical solution to the above problems at present is the use of a plasma technology for coal torch ignition based on thermochemical preparation of fuel for combustion. The materials of the developments of JSC “NPO CKTI” on application of plasmatrons in boilers of thermal power plants at metallurgical complexes of the Russian Federation are also considered.Plasma ignition systems for solid fuels in boilers were developed by Russian specialists and were introduced at a number of coal-fi red power plants in the Russian Federation, Mongolia, North Korea, and Kazakhstan. Plasma ignition of solid fuels is widely used in China for almost 30% of power boilers.The introduction of plasma-energy technologies will improve the energy efficiency of domestic solid-fuel thermal power plants and can be widely implemented in the modernization of boilers.During the construction of new TPPs, the construction of fuel oil facilities can be abandoned altogether, which will reduce the capital costs of the construction of thermal power plants, reduce the construction footprint, and increase the TPP safety.

Life Cycle Analysis: Sub-Critical Pulverized Coal (SubPC) Power Plants

2018 ◽  
Author(s):  
Timothy J Skone ◽  
Greg Schivley ◽  
Matthew Jamieson ◽  
Joe Marriott ◽  
Greg Cooney ◽  
...  
Keyword(s):  
Life Cycle ◽  
Life Cycle Analysis ◽  
Power Plants ◽  
Pulverized Coal
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