Design of a 2 x 160 MWel CFB Boiler Utilizing High Sulfur Turkish Lignite

Author(s):  
Guenter Scheffknecht ◽  
Nevin Selc¸uk

Advantages of fluidized bed combustion technology such as the ability to burn wide variety of fuels efficiently and to control pollutant emissions without flue gas treatment systems have led to a steady increase in its commercial use over the past decades. There exist widely spread lignite reserves in Turkey with an estimated total quantity of 8 billion tons. A major proportion of this indigenous lignite is characterized by high sulfur, moisture and ash contents. CFBC is the fastest growing and still developing technology especially for such indigenous fuels. Meeting the environmental requirements needs high desulfurization efficiency. Special emphasis must therefore be given to the optimum use of the desulfurization agents, normally limestone, to achieve economical operation and to minimize solid by-product generation. This paper deals with a 2 × 160 MWel CFB plant, currently under construction in C¸an, Turkey. Indigenous lignite with a sulfur content of more than 8% (daf) will be utilized. In order to test the performance of Turkish lignites from C¸an mines, firing tests were performed at the 1.2 MW CFBC test rig at the Niederaussem power plant of RWE Rheinbraun in Germany. Main objective of the tests was to evaluate the sulfur retention efficiency to comply with Turkish emission limits.

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Chang-Sang Cho ◽  
Jae-Hwan Sa ◽  
Ki-Kyo Lim ◽  
Tae-Mi Youk ◽  
Seung-Jin Kim ◽  
...  

This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH4), Nitrous oxide (N2O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH4and N2O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH4and N2O exhausted from the CFB boiler. As a result, the emission factors of CH4and N2O are 1.4 kg/TJ (0.9–1.9 kg/TJ) and 4.0 kg/TJ (2.9–5.3 kg/TJ) within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N2O emission, compared to the emission factor of the CFB boiler using fossil fuel.


Author(s):  
Nevin Selc¸uk ◽  
Aykan Batu ◽  
Olcay Oymak

NOx emissions from fluidized bed combustion of various coals have extensively been investigated and well documented. However, NOx emissions from combustion of Turkish lignites with high ash, volatile matter and sulfur contents have not drawn much attention to date. Recent trend in utilization of indigenous lignites in fluidized bed boilers necessitated investigation of pollutant emissions and adaptation of fluidized bed combustion technology to these lignites. In this study, experimental results of various runs pertaining to the formation and emission of NOx from METU 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) test rig burning typical indigenous lignites; Aydin without limestone addition and Beypazari with and without limestone addition are presented. NOx profiles along the combustor show that concentrations are higher in bed compared to those in freeboard and that conditions leading to higher unburned volatiles in freeboard enhances NOx reduction in that region. Limestone addition results in higher concentrations of NOx in bed but lower concentrations in freeboard, albeit insignificantly.


Author(s):  
Eleni Agelidou ◽  
Martin Henke ◽  
Thomas Monz ◽  
Manfred Aigner

Residential buildings account for approximately one fifth of the total energy consumption and 12 % of the overall CO2 emissions in the OECD countries. Replacing conventional boilers by a co-generation of heat and power in decentralized plants on site promises a great benefit. Especially, micro gas turbine (MGT) based combined heat and power systems are particularly suitable due to their low pollutant emissions without exhaust gas treatment. Hence, the overall aim of this work is the development of a recuperated inverted MGT as heat and power supply for a single family house with 1 kWel. First, an inverted MGT on a Brayton cycle MGT was developed and experimentally characterized, in previous work by the authors. This approach allows exploiting the potential of using the same components for both cycles. As a next step, the applicability of the Brayton cycle components operated in inverted mode needs to be evaluated and the requirements for a component optimization need to be defined, both, by pursuing thermodynamic cycle simulations. This paper presents a parametrization and validation of in-house 1D steady state simulation tool for an inverted MGT, based on experimental data from the inverted Brayton cycle test rig. Moreover, a sensitivity analysis is conducted to estimate the influence of every major component on the overall system and to identify the necessary optimizations. Finally, the component requirements for an optimized inverted MGT with 1 kWel and 16 % of electrical efficiency are defined. This work demonstrates the high potential of an inverted MGT for a decentralized heat and power generation when optimizing the system components.


Author(s):  
Han-Ping Chen ◽  
Xian-Hua Wang ◽  
Shi-Hong Zhang ◽  
De-Chang Liu ◽  
Yu-Hua Lai ◽  
...  

In China, there are a large number of pulverized coal-fired industrial boilers, whose steam capacities are usually relatively small. These boilers can burn only high-grade coal and have low combustion efficiency. Furthermore, the combustion emissions, such as SO2 and NOx, pollute the environment severely. Therefore it is very important and urgent to adopt economically efficient and environmentally friendly technologies to retrofit these boilers. At the same time, there are many industrial wastes, such as bagasse, wood waste, rubbish, petroleum coke and so on, need burning disposal in China. Fluidized bed combustion technology is a kind of clear combustion technology, which has many advantages, such as excellence fuel flexibility, high combustion efficiency, low pollutant emission and good turndown capability etc. So, adopting fluidized bed combustion technology, retrofitting pulverized coal-fired boiler into fluidized bed boiler can realize pure burning various wastes or co-firing with coal, which should have great economic benefits and social benefits. And the application prospect of the method is also extensive. The State Key Laboratory of Coal Combustion has successfully retrofitted a 25t/h pulverized coal-fired boiler into circulating fluidized bed boiler with in-bed tubes and downward exhaust cyclone. The retrofitted boiler can burn mixture of coal and bagasse and the steam capacity reaches 35t/h. This paper presents the retrofitting measures and the operation status of the boiler after retrofitting.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3436 ◽  
Author(s):  
Guan-Bang Chen ◽  
Samuel Chatelier ◽  
Hsien-Tsung Lin ◽  
Fang-Hsien Wu ◽  
Ta-Hui Lin

Co-combustion technology can be a gateway to sewage sludge valorization and net CO2 reduction. In this study, combustion characteristics of sewage sludge, Australian black coal, shiitake substrate, and their blends were analyzed via thermogravimetric analysis (TGA) coupled with Fourier transform infrared spectroscopy. The ignition temperature, burnout temperature, flammability index (C), and combustion characteristics index (S) of the fuels and their respective blends were estimated. Kinetic parameters were also estimated using the Coats-Redfern method. The results showed that the oxidation of the blends had two distinct stages. Synergistic effects existed for all the blends, with negative ones occurring at temperatures between 300 and 500 °C and positive ones during the char oxidation period. In the first oxidation stage, both C and S indexes increased with sludge addition to the coal. However, they decreased with sludge addition in the final oxidation stage. The catalytic effect of the sludge and the shiitake was pronounced in the final oxidation stage and it resulted in a decrease of activation energy. As for the pollutant emissions, the results showed that NOx and SO2 emissions decreased for 25 wt.% sludge addition to the coal. For the sludge-shiitake blends, NOx and SO2 emissions decreased with increasing shiitake addition. The single-pellet combustion results showed that ignition delay time reduced with increasing sludge/coal ratio but increased with increasing sludge/shiitake ratio. The volatile combustion duration decreased with the addition of sludge and total combustion time decreased sharply with increasing sludge ratio.


Author(s):  
Heiner Zwahr

Up to now the emissions of waste-to-energy plants have been of major concern for the operators of waste incineration plants and the public. In Germany the emission standards for waste incineration plants have been very strict for more than 10 years, more stringent than for coal fired power plants, for example. Now the member states of the European Union are following suit with the same standards in accordance with European directive 2000/76/EC on the incineration of waste. Within a couple of years all European waste incineration plants will have to comply with the emission limits of directive 2000/76/EC. There is also legislation in the pipeline restricting landfilling of untreated waste. In view of the discussions about CO2 reductions the efficiency of today’s Waste to Energy (WTE) plants should be improved, even though — or rather because — waste is regarded to some extent as “green power”. With the same goal in mind the recovery rate of reusable materials from the incineration of waste or flue gas treatment should be improved. This will make it possible to reduce the amount of CO2 generated by the production of these materials from natural resources and to conserve natural resources.


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