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.

Artificial Intelligence-Based Emission Reduction Strategy for Limestone Forced Oxidation Flue Gas Desulfurization System

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Ghulam Moeen Uddin ◽  
Syed Muhammad Arafat ◽  
Waqar Muhammad Ashraf ◽  
Muhammad Asim ◽  
Muhammad Mahmood Aslam Bhutta ◽  
...  
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Operating Conditions ◽  
Process Models ◽  
Flue Gas Desulfurization ◽  
Optimum Operating ◽  
Input Control ◽  
Network Process ◽  
Coal Power Plants ◽  
Forced Oxidation

Abstract The emissions from coal power plants have serious implication on the environment protection, and there is an increasing effort around the globe to control these emissions by the flue gas cleaning technologies. This research was carried out on the limestone forced oxidation (LSFO) flue gas desulfurization (FGD) system installed at the 2*660 MW supercritical coal-fired power plant. Nine input variables of the FGD system: pH, inlet sulfur dioxide (SO2), inlet temperature, inlet nitrogen oxide (NOx), inlet O2, oxidation air, absorber slurry density, inlet humidity, and inlet dust were used for the development of effective neural network process models for a comprehensive emission analysis constituting outlet SO2, outlet Hg, outlet NOx, and outlet dust emissions from the LSFO FGD system. Monte Carlo experiments were conducted on the artificial neural network process models to investigate the relationships between the input control variables and output variables. Accordingly, optimum operating ranges of all input control variables were recommended. Operating the LSFO FGD system under optimum conditions, nearly 35% and 24% reduction in SO2 emissions are possible at inlet SO2 values of 1500 mg/m3 and 1800 mg/m3, respectively, as compared to general operating conditions. Similarly, nearly 42% and 28% reduction in Hg emissions are possible at inlet SO2 values of 1500 mg/m3 and 1800 mg/m3, respectively, as compared to general operating conditions. The findings are useful for minimizing the emissions from coal power plants and the development of optimum operating strategies for the LSFO FGD system.

scholarly journals Study on the preparation and properties of talcum-fly ash based ceramic membrane supports

2020 ◽  
Author(s):  
Chao Cheng ◽  
Hongming Fu ◽  
Heng Zhang ◽  
Haiping Chen ◽  
Dan Gao
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Flue Gas ◽  
Power Plants ◽  
Ceramic Membrane ◽  
Low Cost ◽  
Water Flux ◽  
Ceramic Membranes ◽  
Operating Conditions ◽  
Water Recovery

Abstract Ceramic membrane method for moisture recovery from flue gas of thermal power plants is of considerable interest due to its excellent selection performance and corrosion resistance. However, manufacturing costs of commercial ceramic membranes are still relatively expensive, which promotes the development of new methods of preparing low-cost ceramic membranes. In this study, a method for the preparation of porous ceramic membrane supports is proposed. Low-cost fly ash from power plants is the main material of the membrane supports, and talcum is the additive. The fabrication process of the ceramic membrane supports is described in detail. The properties of the supports were fully characterized, including surface morphology, phase composition, pore diameter distribution and porosity. Corrosion resistance and mechanical strength of the supports were measured. The obtained ceramic membrane support displays a pore size of about 5 µm and porosity of 37.8%. Furthermore, the water recovery performance of the supports under different operating conditions was experimentally studied. The experimental results show that, the recovered water flux varies with operating conditions. In the study, the maximum recovered water flux reaches 5.22 kg/(m2·h). The findings provide a guidance for the ceramic membrane supports application of water recovery from flue gas.

scholarly journals The Prototype of Non-thermal Plasma After treatment System for Simultaneous Reduction of Nitrogen Oxide Emission in Flue Gas

2021 ◽  
Vol 302 ◽  
pp. 01010
Author(s):  
Dararat Laohalertdecha ◽  
Kampanart Theinnoi ◽  
Sak Sittichompoo
Keyword(s):  
Nitrogen Oxides ◽  
Nitrogen Oxide ◽  
Flue Gas ◽  
Thermal Plasma ◽  
Power Plants ◽  
Gas Flow ◽  
Nox Reduction ◽  
Combustion Process ◽  
Operating Conditions ◽  
Non Thermal Plasma

Nowadays, global warming is the main environmental problems all over the world. The air pollutants mainly from the burning of fossil fuels and coal in power plants, transportation, and automobiles. There are release major point emission of the atmosphere. The nitrogen oxides are the most relevant for air pollution that contribute to the formation of photochemical smog and acid rain. Numerous methods have been studied to eliminate the nitrogen oxides such as the use low-nitrogen fuels technology, the selective catalytic reduction (SCR), wet scrubbing. The aim of this research is investigated non-thermal plasma (NTP) techniques offer an innovation to eliminate both nitrogen oxide (NOx) and soot emissions from combustion. This study is used to selectively transfer input electrical energy to electrons without expending this in heating the entire gas flow which creates free radicals in the flue gases. The simulated flue gas from combustion process is applied to the system. The results showed that the prototype of nonthermal plasma system is shown the highly efficient of NOx removal was achieved. However, the optimised of NTP operating conditions are required to enhance the NOx reduction activities.

Comparative System Performance Analysis of Direct Steam Generation Central Receiver Solar Thermal Power Plants in Megawatt Range

2014 ◽  
Vol 136 (1) ◽  
Author(s):  
Javier Sanz-Bermejo ◽  
Víctor Gallardo-Natividad ◽  
José Gonzalez-Aguilar ◽  
Manuel Romero
Keyword(s):  
Power Plants ◽  
Superheated Steam ◽  
Thermal Power ◽  
Solar Thermal ◽  
Saturated Steam ◽  
Thermal Power Plants ◽  
Steam Generation ◽  
Optical Efficiency ◽  
Solar Thermal Power ◽  
Central Receiver

This work proposes and analyses several integration schemes specially conceived for direct steam generation (DSG) in megawatt (MW) range central receiver solar thermal power plants. It is focused on the optical performance related to the heliostat field and the arrangement of receiver absorbers, and the management of steam within a Rankine cycle in the range between 40–160 bar and 400–550 °C at design point. The solar receiver is composed of one single element for saturated steam systems or two vertically aligned separated units, which correspond to the boiler and the superheater (dual-receiver concept), for superheated steam solar thermal power plants. From a fixed heliostat field obtained after layout optimization for the saturated steam solar plant the heliostat field is divided in two concentric circular trapezoids where each of them independently supplies the solar energy required by the boiler and the superheater for the different steam conditions. It has been observed that the arrangement locating the boiler above the superheater provides a slightly higher optical efficiency of the collector system, formed by the solar field and the receiver, compared with the reverse option with superheater above boiler. Besides, two-zone solar fields provide lower performances than the entire heliostat layout aiming at one absorber (saturation systems). Optical efficiency of two-zone solar fields decreases almost linearly with the increment of superheater heat demand. Concerning the whole solar collector, heliostat field plus receiver, the performance decreases with temperature and almost linearly with the steam pressure. For the intervals of steam pressure and temperature under analysis, solar collector of saturated steam plant achieves an optical efficiency 3.2% points higher than the superheated steam system at 40 bar and 400 °C, and the difference increases up to 9.3% points when compared with superheated system at 160 bar and 550 °C. On the other hand, superheated steam systems at 550 °C and pressure between 60 and 80 bar provide the highest overall efficiency, and it is 2.3% points higher than performance of a saturated steam solar plant at 69 bar. However, if saturated steam cycle integrates an intermediate reheat process, both would provide similar performances. Finally, it has been observed that central receiver systems (CRS) producing saturated steam and superheated steam at 500 °C operating at 40 bar provide similar performances.

Performance Analysis of Direct Steam Generation-Central Receiver Systems

2012 ◽  
Author(s):  
Javier Sanz-Bermejo ◽  
José Gonzalez-Aguilar ◽  
Manuel Romero
Keyword(s):  
Power Plants ◽  
Superheated Steam ◽  
System Analysis ◽  
Live Steam ◽  
Saturated Steam ◽  
Steam Generation ◽  
Central Receiver ◽  
Power Block ◽  
Direct Steam ◽  
Solar Field

This work presents a comparative study between direct steam generation central receiver solar power plants working at live steam conditions similar to those found in commercial plants. PS10 and PS20 by Abengoa Solar use a single-receiver, producing saturated steam, whereas Sierra SunTower by e-Solar and Ivanpah Solar Electric Generating System (ISEGS) by BrightSource use dual-receiver technology producing superheated steam. The system analysis includes individual studies for each subsystem: solar field, receiver and Rankine power block; as well as the overall-analysis of a 66.7 MWth plant. PS10 working conditions were analysed with and without intermediate reheat step. It was assumed that Sierra SunTower-configuration has non-reheat turbine and Ivanpah-cycle includes an intermediate reheat step. The reheat process in PS10 configuration was performed using a fraction of live steam coming from the receiver; while for Ivanpah-configuration exhaust steam from high pressure turbine stage was sent back to the superheated steam section of the dual-receiver. These concepts make possible to avoid hybridisation and assure special regimes (such as Spanish feed-in tariff). The analysis of the heliostat field for dual-receiver concepts reveals that the aiming strategy on the absorbers has not relevant influence on optical performances. However, receiver efficiency decreased from 91.9%, working with saturated steam, to 87.86–84.14% working with superheated steam related to operating temperatures and heat exchange surface area. This study reveals that the improvement achieved in the power block under Ivanpah configuration was able to compensate higher thermal losses at the receiver, increasing net power production by 25.5% compared with saturated steam conditions.

scholarly journals Study on the Preparation and Properties of Talcum-Fly Ash Based Ceramic Membrane Supports

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 207
Author(s):  
Chao Cheng ◽  
Hongming Fu ◽  
Jun Wu ◽  
Heng Zhang ◽  
Haiping Chen
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Power Plants ◽  
Ceramic Membrane ◽  
Low Cost ◽  
Thermal Power ◽  
Water Flux ◽  
Ceramic Membranes ◽  
Operating Conditions ◽  
Water Recovery

Ceramic membrane method for moisture recovery from flue gas of thermal power plants is of considerable interest due to its excellent selection performance and corrosion resistance. However, manufacturing costs of commercial ceramic membranes are still relatively expensive, which promotes the development of new methods for preparing low-cost ceramic membranes. In this study, a method for the preparation of porous ceramic membrane supports is proposed. Low-cost fly ash from power plants is the main material of the membrane supports, and talcum is the additive. The fabrication process of the ceramic membrane supports is described in detail. The properties of the supports were fully characterized, including surface morphology, phase composition, pore diameter distribution, and porosity. The mechanical strength of the supports was measured. The obtained ceramic membrane supports displays a pore size of about 5 μm and porosity of 37.8%. Furthermore, the water recovery performance of the supports under different operating conditions was experimentally studied. The experimental results show that the recovered water flux varies with operating conditions. In the study, the maximum recovered water flux reaches 5.22 kg/(m2·h). The findings provide a guidance for the ceramic membrane supports application of water recovery from flue gas.

Use of Condensing Heat Exchangers in Coal-Fired Power Plants to Recover Flue Gas Moisture and Capture Air Toxics

2013 ◽  
Author(s):  
Edward Levy ◽  
Harun Bilirgen ◽  
Joshua Charles ◽  
Mark Ness
Keyword(s):  
Water Vapor ◽  
Heat Exchanger ◽  
Power Plant ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Power Plants ◽  
Operating Conditions ◽  
Dew Point ◽  
Air Toxics ◽  
Condensing Heat Exchanger

Heat exchangers, which cool boiler flue gas to temperatures below the water vapor dew point, can be used to capture moisture from flue gas and reduce external water consumption for power plant operations. At the same time, thermal energy removed from the flue gas can be used to improve unit heat rate. Recent data also show that emissions of air toxics from flue gas would be reduced by use of condensing heat exchangers. This paper describes results from a slip stream test of a water cooled condensing heat exchanger system at a power plant with a lignite-fired boiler. The flue gas which flowed through the heat exchangers had been extracted from a duct downstream of the electrostatic precipitator. Measurements were made of flue gas and cooling water temperatures, flue gas water vapor concentrations, and concentrations of elemental and oxidized Hg at the inlet and exit of the heat exchanger system. Condensed water was also collected and analyzed for concentrations of H2SO4 and HCl. Results on the effects of the condensing heat exchanger operating conditions on oxidation and capture of Hg and on the capture of sulfuric and hydrochloric acids are described.

scholarly journals Improving the Carbon Capture Efficiency for Gas Power Plants through Amine-Based Absorbents

2020 ◽  
Vol 13 (1) ◽  
pp. 72
Author(s):  
Saman Hasan ◽  
Abubakar Jibrin Abbas ◽  
Ghasem Ghavami Nasr
Keyword(s):  
Climate Change ◽  
Flue Gas ◽  
Carbon Capture ◽  
Power Plants ◽  
Environmental Concern ◽  
Co2 Reduction ◽  
Operating Conditions ◽  
Circulation Rate ◽  
Co2 Removal ◽  
Reduction Of Co2

Environmental concern for our planet has changed significantly over time due to climate change, caused by an increasing population and the subsequent demand for electricity, and thus increased power generation. Considering that natural gas is regarded as a promising fuel for such a purpose, the need to integrate carbon capture technologies in such plants is becoming a necessity, if gas power plants are to be aligned with the reduction of CO2 in the atmosphere, through understanding the capturing efficacy of different absorbents under different operating conditions. Therefore, this study provided for the first time the comparison of available absorbents in relation to amine solvents (MEA, DEA, and DEA) CO2 removal efficiency, cost, and recirculation rate to achieve Climate change action through caron capture without causing absorbent disintegration. The study analyzed Flue under different amine-based solvent solutions (monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA)), in order to compare their potential for CO2 reduction under different operating conditions and costs. This was simulated using ProMax 5.0 software modeled as a simple absorber tower to absorb CO2 from flue gas. Furthermore, MEA, DEA, and MDEA adsorbents were used with a temperature of 38 °C and their concentration varied from 10 to 15%. Circulation rates of 200–300 m3/h were used for each concentration and solvent. The findings deduced that MEA is a promising solvent compared to DEA and MDEA in terms of the highest CO2 captured; however, it is limited at the top outlet for clean flue gas, which contained 3.6295% of CO2 and less than half a percent of DEA and MDEA, but this can be addressed either by increasing the concentration to 15% or increasing the MEA circulation rate to 300 m3/h.

Prediction of the Remaining Service Life of Superheater and Reheater Tubes in Coal-Biomass Fired Power Plants

2013 ◽  
Vol 856 ◽  
pp. 343-348 ◽  
Author(s):  
Mohammad Asgaryan ◽  
Nigel Simms ◽  
Shao Min Wu
Keyword(s):  
Service Life ◽  
Power Plants ◽  
Operating Conditions ◽  
Fireside Corrosion ◽  
Remaining Service Life ◽  
Boiler Efficiency ◽  
Early Failures ◽  
Oxidation Damage ◽  
Type Of Failure ◽  
The Impact

Burning biomass in power plants is believed to result in severe fireside corrosion of superheater/reheater tubing and cause unexpected early failures of tubes. Morover, higher operating temeprtures and pressures (to increase the boiler efficiency) will also increase the risk of fireside and steamside oxidation damage to the boiler tubing and lead to shorter component lives. Predicting the remaining service life of superheater/reheater tubes in coal-biomass fired power plants is therefore an important aspect of managing such power plants. The path to this type of failure of tubes involves five processes: combustion, deposition, fireside corrosion, steam-side oxidation, and creep. To fully understand the impact of new fuel mixes and changing operating conditions on such failures, an integrated model of all of these processes is required. This work has produced an integrated set of models and so predicted the remaining life of tubes based on the conceptual and mathematical frameworks developed.

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