CO2 emission during the combustion of Orhaneli lignite coal

2017 ◽  
Vol 14 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Mehmet Ozkaymak ◽  
Mehmet Ali Ceylan ◽  
Hasancan Okutan ◽  
Hüsnü Atakul ◽  
Engin Berrin ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Side Reactions ◽  
Content Type ◽  
Positive Effects ◽  
Bed Temperature ◽  
Combustion Technology ◽  
Combustion Experiment ◽  
Lignite Coal

Purpose In Turkey, dependence on foreign countries for energy is a problem which upsets all economic balances. Turkey’s biggest fossil energy source is lignite coal. Therefore, energy conversion of lignite in thermal plants, causing minimum environmental effect is extremely important. The basic problem in terms of the combustion technology is to improve the combustion technology that can burn the low-qualified fuels that do not have standard fuel features (lignite, peat, schist). The most suitable technology today for the efficient and clean combustion of nonstandard low-qualified fuels is the combustion at fluidized-bed technology. In this study, CO2 emission that occurs during the combustion of Orhaneli coal that is one of our native low-qualified lignite, has been investigated according to the experimental study. Design/methodology/approach For this combustion experiment, laboratory-scaled circulating fluidized-bed (CFB) process that exists at TÜBITAK-MAM Energy Institute which has been designed and used before has been used. The effect of excess-air coefficient, combustion type and bed temperature to the greenhouse gas formation and CO2 emission has been investigated experimentally. In terms of flue gas emissions, it has been detected that the decrease of the amount of CO2 that has occurred has no positive effects on combustion efficiency, water vapor, SO2, NOx, CO and other gases which occur during deficient combustion must be thought as a whole and each reaction affects each other similar to complex reactions. Findings As a consequence of measuring CO2 emissions over 10 minute periods, CO2 emissions are 12.43 percent average, CO2 decreases at different air coefficient values; Often form undesirable side reactions such as CO, NOx with back and forth reactions. Originality/value The importance of aerodynamic structure of the system, and the losses and leakages forming in the system has been observed experimental and affected parameters are evaluated.

Retrofitting 25T/h Pulverized Coal-Fired Boiler Into 35T/h Circulating Fluidized Bed Boiler for Burning Mixture of Coal and Bagasse

2005 ◽  
Author(s):  
Han-Ping Chen ◽  
Xian-Hua Wang ◽  
Shi-Hong Zhang ◽  
De-Chang Liu ◽  
Yu-Hua Lai ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Economic Benefits ◽  
Pulverized Coal ◽  
Industrial Wastes ◽  
Pollutant Emission ◽  
Fluidized Bed Combustion ◽  
Circulating Fluidized Bed Boiler ◽  
Combustion Technology

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.

Combustion of Wood Processing Residues in a Circulating Fluidized Bed

2003 ◽  
Author(s):  
Fernando Preto
Keyword(s):  
Fluidized Bed ◽  
Pilot Plant ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Tree Bark ◽  
Feed System ◽  
Wood Processing ◽  
System A ◽  
Bed Temperature ◽  
High Moisture Level

The combustion of wood processing residues was tested in the 0.8 MWth CANMET Circulating Fluidized Bed Combustor (CFBC) pilot plant. The specific residues tested were three different types of coniferous tree bark (i.e. from different locations to represent a range of possible fuels and fuel properties). Combustion conditions may be summarized as follows: fuel moisture levels 42–60%, fluidizing velocity 2.1–2.4 m/s; bed temperature 785–910 °C; maximum freeboard temperature 980–1070 °C and excess air levels 20–75%. The CFBC unit was able to burn the high moisture level fuels with no detrimental effect. In all trials the residues burned very well, with combustion efficiency greater than 99% based on overhead carbon loss. Emissions measurements were made of the following pollutant species CO, NOx, N2O, SO2, and dioxins and furans. The emissions levels were: 100–130 ppm NOx; <1 ppm N2O; 5–20 ppm SO2 and 400–1800 ppm CO. These emission levels are well below pollution guidelines for all major pollutants except CO. This however can be traced to the non-homogeneous nature of the coarse feed in the pilot plant. The problem can reasonably be addressed in a full-scale unit by a more stable feed system. A preliminary economic analysis of a new 25 MW FBC power plant firing these fuels was performed. Conservative inputs give a cost of 6 cents/kWh for the electricity produced and a economic wood haulage radius of 70 km.

The Local Heat Balance in a Stationary Fluidized-Bed Furnace Burning Biomass Fuels

2003 ◽  
Author(s):  
Fredrik Niklasson ◽  
Filip Johnsson
Keyword(s):  
Fluidized Bed ◽  
Combustion Rate ◽  
Heat Balance ◽  
Circulating Fluidized Bed ◽  
Local Heat ◽  
Splash Zone ◽  
Two Phase ◽  
Bed Temperature ◽  
Temperature Constant ◽  
The Vertical Distribution

This work investigates the influence of biomass fuel properties on the local heat balance in a commercial-scale fluidized bed furnace. Experiments with different wood based fuels were performed in the Chalmers 12 MWth circulating fluidized bed boiler, temporarily modified to run under stationary conditions. A two-phase flow model of the bed and splash zone is applied, where the combustion rate in the bed is estimated by global kinetic expressions, limited by gas exchange between oxygen-rich bubbles and a fuel-rich emulsion phase. The outflow of bubbles from the bed is treated as “ghost bubbles” in the splash zone, where the combustion rate is determined from turbulent properties. It is found that a large amount of heat is required for the fuel and air to reach the temperature of the bed, in which the heat from combustion is limited by a low char content of the fuel. This implies that a substantial fraction of the heat from combustion of volatiles in the splash zone has to be transferred back to the bed to keep the bed temperature constant. It is concluded that the moisture content of the fuel does not considerably alter the vertical distribution of heat emitted, as long as the bed temperature is kept constant by means of flue gas recycling.

Identification of Circulating Fluidized Bed Boiler Bed Temperature Based on Hyper-Plane-Shaped Fuzzy C-Regression Model

2020 ◽  
Vol 19 (04) ◽  
pp. 2050029
Author(s):  
Jianzhong Shi
Keyword(s):  
Regression Model ◽  
Fluidized Bed ◽  
Membership Function ◽  
Clustering Algorithm ◽  
Circulating Fluidized Bed ◽  
Fuzzy Model ◽  
Identification Algorithm ◽  
Identification Process ◽  
Bed Temperature ◽  
Hyper Plane

Bed temperature in dense-phase zone is the key parameter of circulating fluidized bed (CFB) boiler for stable combustion and economic operation. It is difficult to establish an accurate bed temperature model as the complexity of circulating fluidized bed combustion system. T-S fuzzy model was widely applied in the system identification for it can approximate complex nonlinear system with high accuracy. Fuzzy c-regression model (FCRM) clustering based on hyper-plane-shaped distance has the advantages in describing T-S fuzzy model, and Gaussian function was adapted in antecedent membership function of T-S fuzzy model. However, Gaussian fuzzy membership function was more suitable for clustering algorithm using point to point distance, such as fuzzy c-means (FCM). In this paper, a hyper-plane-shaped FCRM clustering algorithm for T-S fuzzy model identification algorithm is proposed. The antecedent membership function of proposed identification algorithm is defined by a hyper-plane-shaped membership function and an improved fuzzy partition method is applied. To illustrate the efficiency of the proposed identification algorithm, the algorithm is applied in four nonlinear systems which shows higher identification accuracy and simplified identification process. At last, the algorithm is used in a circulating fluidized bed boiler bed temperature identification process, and gets better identification result.

Combustion Behavior and SO2, NOx Emissions of an Anthracite Coal in a Circulating Fluidized Bed

2005 ◽  
Author(s):  
Leming Cheng ◽  
Zhongyang Luo ◽  
Zhenglun Shi ◽  
Haixiao Zheng ◽  
Qinghui Wang ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Cross Section ◽  
Circulating Fluidized Bed ◽  
Nox Emissions ◽  
So2 Emission ◽  
Combustion Behavior ◽  
Excess Air ◽  
Anthracite Coal ◽  
Bed Temperature ◽  
Experimental Researches

Combustion behavior and SO2, NOx emissions of anthracite coal in a circulating fluidized bed are reported in this paper. Experimental researches were done on a 1 MWt circulating fluidized bed facility with a 0.31 m × 0.31 m cross section and 11.2 m height combustor. The anthracite coal with 6.28% volatile and 3.76% sulfur content burns steadily during the test. The bed was operated under different temperature, Ca/S ratio and excess air. A limestone containing 75% CaCO3 and 15% MgCO3 was used as the sulfur sorbent. Results show that the SO2 emission varies with operating bed temperature and more than 90% sulfur capture efficiency can be reached while Ca/S is about 3. With Rosemount Analytical NGA2000, N2O, NO and NO2 were also measured in the test. It was found the majority content of NOx was NO and the least was NO2. Those NOx emissions change highly with the excess air number.

Co-combustion of olive cake with lignite coal in a circulating fluidized bed

Fuel ◽  
2004 ◽  
Vol 83 (7-8) ◽  
pp. 859-867 ◽  
Author(s):  
Aysel T Atimtay ◽  
Hüseyin Topal
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Olive Cake ◽  
Lignite Coal
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