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Optimization of a Cement Plant Preheating Tower, Equipped with a Precalciner, Burning Pulverized Coal
Published in Maria da Graça Carvalho, Woodrow A. Fiveland, F. C. Lockwood, Christos Papadopoulos, Combustion Technologies for a Clean Environment, 2021
C. Belot, D. Goffe, D. Grouset, C. Bertrand, B. Homassel, J. L. Philippe
The correction coefficient a has been introduced to account for the specific operating conditions of the precalciner (lack of oxygen and high concentrations of CO2). The value α = 0, 1 has been found to correlate satisfactorily from experiments by Gadiou and Prado (1987) on coal samples used at the LEXOS plant. In these experiments a drop tube furnace was used characterize the combustion of single coal particles under controlled temperature and partial pressure of oxygen. The experimental data are the delays taken by each step in the combustion process. By a data regression procedure, relations can be developped to correlate the combustion time with burner temperature and oxygen concentration. In our case, one obtains:
Physicochemical Properties of Coal
Published in Vivek Ranade, Sanjay Mahajani, Ganesh Samdani, Computational Modeling of Underground Coal Gasification, 2019
Vivek Ranade, Sanjay Mahajani, Ganesh Samdani
FTIR and other chromatographic instruments such as GC/MS have also been coupled to TGA (thermogravimetric analyzer) and drop tube furnaces (DTF), providing controlled conditions to study pyrolysis or combustion byproducts. The typical experimental procedure and the spectra used during FTIR are as follows (Singan, 2018):
Study into petrographic characteristics, coal quality and combustion features of several kinds of Chinese energy coals
Published in Wang Yuehan, Ge Shirong, Guo Guangli, Mining Science and Technology, 2004
Xinqian Shu, Wei Qi, Tianji Liu, Xuchang Xu
On the basis of preceding investigation, parameters related to combustion were studied with a Du-Pont thermal balance. And the combustion test was further carried out on a drop tube furnace (DTF) (Shu 1997, Wang 1995, Shu et al. 2000) for YQ and SF samples.
Modelling copper smelting – the flash smelting plant, process and equipment
Published in Mineral Processing and Extractive Metallurgy, 2020
Pekka Taskinen, Ari Jokilaakso, Daniel Lindberg, Jiliang Xia
The modelling of FSF using a commercial CFD software started in early ‘90s and a comprehensive review has been published recently (Sohn 2014). The scope initially included detailed models of the FSF reaction shaft (Jokilaakso et al. 1994) and the WHB (Ahokainen and Jokilaakso 1997; Yang et al. 1999). A more advanced approach with chemical reactions of sulphide particles for both FSF and FCF were made public later (Hahn and Sohn 1987; Järvi et al. 1997; Ahokainen et al. 2006). One of the first developers of FSF simulations by a commercial CFD code published a reaction shaft flow simulation in 1992 (Vaarno et al. 2003), and they included chemical reactions in the model in 2003 (Solnordal et al. 2003; Solnordal et al. 2006). Adams et al. (Adams et al. 1999) modelled drop-tube experiments followed by combustion in 1999. In the industrial context, a CFD model of an independent burner development was published in 2006 (Sasaki et al. 2006) materialising in a new side blown burner in 2013 (Nagai et al. 2013). A CFD model for improved FSF burner performance has also been published (Jastrzebski et al. 2013), and Li & Xiao (Li and Xiao 2003) used numerical simulation for browsing production enhancement. An early attempt of FSF simulation with a commercial code was provided already in 1994 by Seo & Rhee (Seo and Rhee 1994).
Effect of rice husk co-combustion with coal on gaseous emissions and combustion efficiency
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Javaid Akhtar, Anum Yaseen, Shahid Munir
Results of the combustion of Lakhra coal using a drop tube furnace are shown in Figure 2. It was found that the concentration of CO2 increased gradually from 9.4 to 14.1% by increasing the temperature from 800 to 1000°C. The decreasing trend of CO emissions was observed during combustion of Lakhra coal because at a low temperature of 800°C, CO was formed in bulk quantity as 713 ppm, but at a high temperature of 1000°C, it reduced to 40 ppm. The basic mechanism for combustion of volatile matter and char could be explained based on Equations (1–4). It would be expected that the conversion of solid to CO would be initiation reaction due to high solid carbon-to-air ratio. Similarly, the presence of moisture in coal would increase the possibility of Boudard gasification reaction, thereby adding CO in gaseous emissions (Yang et al. 2017). The rate of formation of CO2 and disappearance of CO with an increase in temperature were observed as shown in Figure 1. The production of intense phase volatiles and mixing with oxygen would be a good source for conversion of gaseous phase CO to CO2 (Shahzad et al. 2015).
NO Emission and Burnout Characteristic in Combustion of Coal Gasification Fine Slag with Preheating Technology
Published in Combustion Science and Technology, 2023
Xiaohe Xiong, Zhaomin Lyu, Falin Chen, Houzhang Tan
A one-dimensional drop-tube furnace system was employed to achieve the combustion of CGFS following preheating treatment (Figure 2). The current setup has already been used successfully in multiple studies regarding the preheating of semi-coke (Lv et al. 2021) and sludge (Lv et al. 2023). Detailed description of the system can be found in many papers. Briefly, the system includes two drop-tube furnaces both with an inner diameter of 50 mm and a length of 1200 mm. The upper furnace is for preheating and the bottom is for combustion. In our experiments, the CGFS was fed through a screw feeder at a rate of 0.27 ± 0.01 g/min and was introduced into the upper furnace using a water-cooled probe to prevent fuel pyrolysis.