Operating Experience With a Fluidized Bed Test Combustor

1987 ◽  
Vol 109 (2) ◽  
pp. 58-65
Author(s):  
D. C. Hainley ◽  
M. Z. Haji-Sulaiman ◽  
S. Yavuzkurt ◽  
A. W. Scaroni
Keyword(s):  
Fluidized Bed ◽  
Operating Experience ◽  
Experimental Measurements ◽  
Performance Tests ◽  
Fuel Feed ◽  
Bed Height ◽  
Coal Properties ◽  
Primary Focus ◽  
Bed Agglomeration ◽  
Fluidized Bed Combustor

This paper presents operating experience with a fluidized bed combustor burning various coals. The primary focus is on the effect of relevant coal properties on combustor performance. Tests were carried out using anthracite, HVB and HVC bituminous and sub-bituminous A coals, and petroleum coke. Comparisons of the performance of the combustion on the various fuels are made. A two-stage fluidized bed combustor operating in a single-stage mode without recycle was employed. Experimental measurements included temperature, fuel feed rate, fluidization velocity and bed height. For some of the coals, bed agglomeration was found to occur. The results indicate that coal properties have an important effect upon the operation of the fluidized bed combustor.

Pengurangan Pelepasan Emisi dari Pembakar Lapisan Terbendalir Menggunakan Tempurung Kelapa Sawit Sebagai Bahan Api

2012 ◽  
pp. 07-11
Author(s):  
Mohammad Nazri Mohd Jaafar ◽  
Rosyida Permatasari ◽  
Mohd Nazar Yakin Mohd Sobree
Keyword(s):  
Fluidized Bed ◽  
Fuel Oil ◽  
Silica Sand ◽  
Nox Emissions ◽  
Fuel Feed ◽  
Bed Height ◽  
Excess Air ◽  
Axial Temperature ◽  
Fluidized Bed Combustor ◽  
Air Staging

Emissions released from fluidized bed combustor (FBC) are highly dependent on several operating parameters, for example, temperature, staged air, excess air, fuel feed rate, and fuel properties. This paper presents results of experiments conducted using air staging technique on a laboratory scale fluidized bed rig, using palm shells as fuel oil and silica sand as an inert medium. Silica sand was used to ensure a sustainable fuel ignition and stable combustion occurs in the FBC. Emission of CO and NOx emissions, and temperatures along the height of the bed and flue were measured. The experimental results show that the axial temperature profile along the height was proportionally reduced with bed height of FBC. CO and NOx emissions obtained exhibit lower values for the air staged combustion. Pelepasan emisi dari pembakar lapisan terbendalir (FBC) adalah sangat bergantung kepada beberapa parameter kendalian sebagai contoh: suhu, udara berperingkat, udara berlebihan, kadar suapan bahan api, dan sifat bahan api. Kertas kerja ini mempersembahkan keputusan eksperimen yang dilaksanakan menggunakan teknik pemeringkatan udara ke atas rig lapisan terbendalir skala makmal, menggunakan tempurung kelapa sawit sebagai bahan api dan pasir silika sebagai bahan perantara lengai. Pasir silica telah digunakan untuk memastikan pencucuhan bahan api mampan dan pembakaran stabil berlaku di dalam FBC. Pelepasan gas emisi CO dan NOx serta suhu sepanjang ketinggian pembakar dan juga dalam serombong diukur. Keputusan ujikaji menunjukkan bahawa profil suhu paksi berkurangan secara berkadaran sepanjang ketinggian FBC. Pelepasan CO dan NOx yang diperolehi mempamerkan nilai yang lebih rendah untuk keadaan pembakaran dengan pemeringkatan udara.

Ceramic Candle Filter Performance at the Grimethorpe (UK) Pressurized Fluidized Bed Combustor

1992 ◽  
Vol 114 (2) ◽  
pp. 371-379 ◽  
Author(s):  
J. Stringer ◽  
A. J. Leitch
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Porous Ceramic ◽  
Operating Experience ◽  
Filter Element ◽  
Reverse Direction ◽  
Process Conditions ◽  
Filter Performance ◽  
Fluidized Bed Combustor

A pilot hot-gas particulate removal system, based on positive porous ceramic filters, has been tested on the Grimethorpe Pressurized Fluidized Bed Combustor facility. The filters are in the form of closed-ended tubes, 1.5 m long: These are generally called “candles.” The dust accumulates on the outside of the candles, and is periodically removed by a pulse of air into the candle interior, which then flows outward through the candle wall in the reverse direction to the normal flow of the combustion gas. The EPRI system contained a maximum of 130 candles, which is approximately equivalent to the requirement for 7 MW(e) capacity, depending on the filter-operating parameters. The filter unit operated for a total of 860 h under PFBC conditions, of which 790 h were at defined process conditions, typically 850°C and 10 bar. The amount of gas flowing through each filter element was varied, and the time between cleaning pulses also was varied. The pressure drop through each filter element rose as the dust accumulated on the outer wall, and recovered after the cleaning pulse. However, the post-cleaning pressure drop does not recover to the original clean candle value, but increases with time. It is believed that a steady-state value is attained, but the exposure in the Grimethorpe test series was insufficient to establish this unequivocally. During the test, five candles failed. This appears to have been due to mechanical shock, as a result of candles lifting because of excessive pressure differentials across their support plate, and dropping back. The failures are not believed to be intrinsic to the technology. However, in addition a reduction in the strength of the candles with time of exposure was observed. This might also attain a steady-state value, but this too could not be established on the basis of the tests reported in this paper. This is clearly a matter of importance, and further work will be required to determine the suitability of the clay-bonded silicon carbide medium used in these tests for this application. A number of deficiencies in the design of the unit emerged with the operating experience, and suggestions have been made for improvements. However, it is clear that further work on design optimization is required. The pulse-cleaning air usage in the tests was greater than would be economically acceptable in a practical system. Further work needs to be done to optimize the cleaning cycle. Overall, the test was very successful, and, when operating properly, the filters removed essentially all of the dust in the gas exiting from the combustor. Apart from the issues with the candle strength and the pulse-cleaning air usage, the other problems were not believed to be of major importance in the further development of the technology. This paper will summarize the test results, emphasizing the problems of candle durability and the pulse-cleaning system.

scholarly journals Ceramic Candle Filter Performance at the Grimethorpe (UK) Pressurized Fluidized Bed Combustor

1991 ◽  
Author(s):  
John Stringer ◽  
Alan J. Leitch
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Porous Ceramic ◽  
Operating Experience ◽  
Filter Element ◽  
Reverse Direction ◽  
Process Conditions ◽  
Filter Performance ◽  
Fluidized Bed Combustor

A pilot hot gas particulate removal system based on positive porous ceramic filters has been tested on the Grimethorpe Pressurized Fluidized Bed Combustor facility. The filters are in the form of closed ended tubes, 1.5 m long: these are generally called ‘candles’. The dust accumulates on the outside of the candles, and is periodically removed by a pulse of air into the candle interior, which then flows outwards through the candle wall in the reverse direction to the normal flow of the combustion gas. The EPRI system contained a maximum of 130 candles, which is approximately equivalent to the requirement for 7 MW(e) capacity, depending on the filter operating parameters. The filter unit operated for a total of 860 hours under PFBC conditions, of which 790 hours were at defined process conditions, typically 850°C and 10 bar. The amount of gas flowing through each filter element was varied, and the time between cleaning pulses was also varied. The pressure drop through each filter element rose as the dust accumulated on the outer wall, and recovered after the cleaning pulse. However, the post-cleaning pressure drop does not recover to the original clean candle value, but increases with time. It is believed that a steady-state value is attained, but the exposure in the Grimethorpe test series was insufficient to establish this unequivocally. During the test, five candles failed. This appears to have been due to mechanical shock, as a result of candles lifting because of excessive pressure differentials across their support plate, and dropping back. The failures are not believed to be intrinsic to the technology. However, in addition a reduction in the strength of the candles with time of exposure was observed. This might also attain a steady state value, but this too could not be established on the basis of the tests reported in this paper. This is clearly a matter of importance, and further work will be required to determine the suitability of the clay-bonded silicon carbide medium used in these tests for this application. A number of deficiencies in the design of the unit emerged with the operating experience, and suggestions have been made for improvements. However, it is clear that further work on design optimization is required. The pulse cleaning air usage in the tests was greater than would be economically acceptable in a practical system. Further work needs to be done to optimize the cleaning cycle. Overall, the test was very successful, and when operating properly the filters removed essentially all of the dust in the gas exiting from the combustor. Apart from the issues with the candle strength and the pulse cleaning air usage, the other problems were not believed to be of major importance in the further development of the technology. This paper will summarize the test results, emphasizing the problems of candle durability and the pulse cleaning system.

Bed agglomeration characteristics of rice straw combustion in a vortexing fluidized-bed combustor

2015 ◽  
Vol 183 ◽  
pp. 195-202 ◽  
Author(s):  
Feng Duan ◽  
Chien-Song Chyang ◽  
Li-hui Zhang ◽  
Siang-Fong Yin
Keyword(s):  
Fluidized Bed ◽  
Rice Straw ◽  
Bed Agglomeration ◽  
Fluidized Bed Combustor ◽  
Straw Combustion

scholarly journals Combustion Characteristics of Mui and Taru Basin Coal in a Fluidized Bed Combustor

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Brian Ondari ◽  
Zachary Siagi ◽  
Anil Kumar
Keyword(s):  
Fluidized Bed ◽  
Volatile Matter ◽  
Gas Analysis ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Fuel Feed ◽  
Loss Analysis ◽  
Coal Reserves ◽  
Fluidized Bed Combustor

Coal reserves at Mui and Taru in Kitui and Kilifi counties in Kenya are estimated to provide over 400 million tons. Being new discoveries, their properties were investigated using the ASTM standards, while the combustion characteristics were studied in a fluidized bed combustor (FBC). Proximate analyses of the Mui1, Mui2, and Taru coal samples were as follows: moisture content 3.75, 5.48, and 3.53%; volatile matter 59.25, 58.05, and 55.10%; ash content 9.25, 11.48, and 24.63%; and fixed carbon 27.80, 25.00, and 16.75%, respectively. Ultimate analysis for Mui1, Mui2, and Taru coal samples is as follows: sulphur wt.% 1.94, 1.89, and 1.07; carbon 65.68, 60.98, and 51.10%; hydrogen 5.97, 5.70, and 5.09%; nitrogen 0.92, 0.94, and 1.00%; and oxygen 11.62, 12.33, and 11.13%, respectively. Temperature–weight loss analysis showed that for Mui and Taru basin coal, devolatilization starts at 200°C and 250°C, and combustion was complete at 750°C and 650°C, respectively. The maximum temperature obtained in FBC was 855°C at 700 mm height, just above the point of fuel feed, while the minimum was 440°C at height of 2230 mm. Maximum pressure drop was 1.02 mbars at 150 mm, while minimum was 0.67 mbars at 700 mm from the base. Gross calorific values were Mui1 coal, 27090 kJ/kg (grade A), Mui2 coal, 25196 kJ/kg (grade B), and the Taru coal, 21016 kJ/kg (grade C). Flue gas analysis for Taru and Mui coal gave hydrogen sulfide as 20 ppm and 6 ppm, maximum carbon monoxide of 2000 ppm at 600°C, and a decrease in oxygen as combustion progressed to a minimum of 15%, followed by an increase to 20.3%, suggesting depletion of coal. Based on the findings, the coal samples were suitable for commercial use.

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