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Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine
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Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine Q4
Gunung Oh a, Ho Won Ra b, Sung Min Yoon b, Tae Young Mun b, Myung Won Seo b, Jae-Goo Lee a, c, Sang Jun Yoon a, b, * a b c
Advanced Energy Technology, Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea Climate Change Research Division, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea Future Energy Plant Convergence Research Center, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history: Received 26 July 2017 Received in revised form 16 January 2018 Accepted 16 January 2018 Available online xxx
In the present study, a syngas was produced by preparing coal water mixtures of two different concentrations and gasifying the coal water mixtures. An entrained-flow gasifier of 1 ton/day scale was used and, after undergoing a purification process, the produced syngas was applied to a modified diesel engine for power generation. As the gasification temperature increased, the carbon conversion and the cold gas efficiency were found to increase. In the composition of the produced syngas, the content of H2 remained constant, that of CO increased, and those of CO2 and CH4 decreased. The carbon conversion increased with equivalence ratio. A maximum cold gas efficiency of 66.1% was found at the equivalence ratio of 0.43. N2 was additionally supplied to verify the gasification characteristics depending on the gas feed flow rate. The optimum feed flow rate was verified at different slurry concentrations and equivalence ratio. The produced syngas was supplied to a modified diesel engine and operated depending on the syngas feed flow rate and the engine operation conditions. The brake thermal efficiency of the engine was constant regardless of the syngas feed flow rate. The diesel engine showed high efficiency despite the mixing of the syngas. © 2018 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Keywords: Gasification Entrained-flow Coal water mixture Feed flow rate Dual-fuel Diesel engine
1. Introduction The climate change is drawing international attention, and CO2 is considered the major cause of climate change [1]. Hence, to reduce CO2 emission, studies have been continuously conducted for highly efficient and clean utilization of fossil fuels, which are the main sources of carbon emission [2]. Gasification has been studied as one technology to accomplish the highly efficient and clean utilization of fossil fuels. Gasification is a thermochemical technology for producing a syngas containing H2 and CO through a thermochemical reaction of coal, biomass, and other fuels. The produced syngas may be applied to the generation of electric power and as a raw material of chemicals [3,4]. Gasification has advantages over traditional combustion, including less discharge of pollutant, and high thermal efficiency [5,6]. Gasifiers are classified into fixed bed, fluidized bed, and entrained-flow gasifiers. In particular, entrained-flow gasifiers, having a high carbon conversion and a high efficiency, are used in such processes as integrated gasification combined cycle (IGCC) [7e9]. Various fuels, such as coal, biomass [10,11], glycerin [12], coke [13], and bio-oil [14], have been studied as fuels for entrained-flow gasification, and gasification for waste treatment has also been conducted [15]. Among these fuels, coal is extensively used because it is widely available and its reserves are plentiful, and coal consumption is expected to continue into the future [16,17]. With regard to entrained-flow gasification of coal, studies have been conducted on gasifiers [18] as well as on gasification agents and gasification kinetics [19]. Coal supply modes in entrained-flow gasification include dry feeding and slurry feeding. Dry feeding, in which coal powder is supplied to a gasifier, gives a high cold gas efficiency and a high carbon conversion and, compared with slurry feeding, allows users to utilize more various types of coal [18]. On the contrary, in slurry feeding, in which coal is supplied as a coal water mixture (CWM), the transportation is
* Corresponding author. Advanced Energy Technology, Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea. E-mail address: [email protected] (S.J. Yoon). https://doi.org/10.1016/j.joei.2018.01.009 1743-9671/© 2018 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
Q1 Q2
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convenient and the pressurization for the gasification reaction is easily performed due to the liquid-like characteristics of CWM. In addition, slurry feeding may prevent scattering and spontaneous ignition of the raw material, enhancing the operational safety. Since the water contained in the CWM is a reactant, the syngas composition and the gasification efficiency were adjusted by varying the CWM concentration. Air and oxygen are commonly used as gasification agents for entrained-flow gasifiers. Air-blown gasification enables a saving of installation and operation costs because it does not require an air separation unit (ASU) for oxygen separation [12]. However, due to the N2 contained in the produced syngas, the heating value of the syngas decreases, and a large purification facility is required. However, oxygenblown gasification shows a higher carbon conversion and cold gas efficiency in comparison with air-blown gasification. In addition, since almost no N2 is injected, little NOx is generated, and CO2 capture from the produced syngas is easier than it is for air-blown gasification. Electric power generation using a produced syngas requires a gas turbine, a gas engine, or a steam turbine depending on the scale. With regard to small and middle-scale power generation, studies are being conducted on not only gas engines but also diesel engines using a mixture of diesel and syngas. Utilization of a mixture of diesel and syngas results in higher efficiency and less generation of NOx, CO2, and particulate matter (PM) in comparison with gas engines [20e22]. Studies have been conducted on various types of diesel engines, such as compression ignition (CI) [23] and high speed direct injection (HSDI) [24], usually using a simulation syngas. While the composition and the flow rate of syngas are dependent on such gasification conditions as slurry concentration, equivalence ratio, and temperature, few studies have been conducted on diesel engines in relation to the variation of these conditions. Therefore, studies should be conducted on the actual application of a syngas produced from a gasifier to a diesel engine for the application to a commercial gasification plant. In the present study, CWM of different concentrations were prepared and gasified in a 1 ton/day scale entrained-flow gasification plant. The syngas produced from the gasification was applied to a modified diesel engine for power generation. The gasification of CWM was conducted by varying the gasification conditions, including the temperature, equivalence ratio, and feed flow rate. To investigate the effect of the CWM concentration on the H2/CO ratio, the syngas composition and gasification efficiency depending on the CWM concentration difference were compared. In addition, the produced syngas was used together with diesel in dual-fuel mode in a modified diesel engine, and the characteristics of the dual-fuel engine operation were also measured. 2. Experimental 2.1. Coal water mixture Table 1 shows the results of the proximate, ultimate, and heating value analysis of the coal used for the preparation of the coal water mixture (CWM). The coal was pulverized into a powder having a size of about 75 mm, which was then mixed with a surfactant (Sikament NN, Sika Korea) and water. To verify the effect on gasification depending on slurry concentration, two types of slurry having different coal concentrations, with carbon/H2O molar ratios of 1.35 (CWM-H, 57.1 wt%) and 1.22 (CWM-L, 54.6 wt%), were prepared with same surfactant. 2.2. Entrained-flow gasification system Fig. 1 is a schematic diagram of the entrained-flow gasifier of 1 ton/day scale used in the present study. Coal and water were mixed in a slurry tank to prepare the CWM, which was then quantitatively supplied using a mono-pump (4B-20, MONAS). The CWM was sprayed into the gasifier through the central hole of a burner attached to the top of the gasifier, and then atomized by contacting the O2 and N2 sprayed from eight holes around the central hole [25]. The O2 and N2 used for the experiment were supplied using a mass flow controller (MFC, Smart mass flow 5853S, BROOKS). The internal diameter and height of the gasifier were 250 mm and 1700 mm, respectively. Three R-type thermocouples were installed to measure the internal temperature distribution. Refractory and insulation materials were used to protect and insulate the gasifier. A K-type thermocouple was installed to monitor the temperature of the refractory and the insulation materials. The ash and slag remaining after the gasification were cooled through contact with the coolant at the bottom of the gasifier, moved to the lockhopper at the bottom of the gasifier, and then discharged. The flow rate of the syngas produced from the gasifier was measured using a vortex flow meter (KODS-KV-01, OVAL KOREA LIMITED), and the composition of syngas was measured using an IR gas analyzer (AO2020, ABB) and a thermal conductivity detector (TCD, carbosphere 80/100 packed column, Alltech) of a gas chromatography (7890A, Agilent). After going through a wet scrubber, a desulfurization unit, and a filter, the syngas was combusted in a dual-fuel engine and a flare stack. According to the experimental conditions, the syngas was injected into a gas mixer using a valve, mixed with the air, and then injected into the diesel engine. The syngas feed flow rate is measured by a vortex flow meter (KODS-KV-01, OVAL KOREA LIMITED), which is installed before gas mixer. The direct injection type diesel engine used in the experiment (D1146T, Doosan Commercial Engine) had a maximum power of 130 kW, and was operated at a constant rate of 1800 rpm using diesel and the syngas produced from the gasifier. The power generation was set at 26 or 40 kW using a resistive load bank. The quantity of injected diesel was automatically controlled by an electronic control unit (ECU) so that the engine could be operated at a constant rate at 1800 rpm. For the preheating of the gasifier, the temperature was raised to 1000 C using LNG. Then, CWM, O2, and N2 were supplied to vary the equivalence ratio (ER) from 0.35 to 0.53. O2 and N2 were supplied at flow rates of 21e30 and 9e12 Nm3/h, respectively, according to the experimental conditions. The carbon conversion (Xc) and cold gas efficiency (CGE) of the gasification, and the brake thermal efficiency (BTE) and syngas replacement ratio (SRR) of the engine, were calculated using the following equations [26e29]: Carbon conversion (%, Xc) ¼ (mass flow of carbon in the syngas)/(mass flow of carbon in the feedstock)*100%
(1)
Table 1 Properties of coal. Fuel
Proximate analysis (Air dry basis), wt%
Ultimate analysis (Dry basis), wt%
HHV (kcal/kg)
Moisture
Volatile
Ash
Fixed carbon
C
H
O
N
S
Coal
6.37
29.2
13.47
50.99
72.1
4.13
8.75
1.51
0.04
6,220
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 1. Schematic diagram of entrained-flow gasification system.
Cold gas efficiency (%, CGE) ¼ ( *100%
P mass flow of H2, CO, CH4*heating value of H2, CO, CH4)/(heating value of feedstock*mass flow of feedstock) (2)
Brake thermal efficiency (%, BTE) ¼ (engine power output)/(
P mass flow of fuel*heating value of fuel)*860 (kcal/hr)/kW*100%
(3)
860 (kcal/hr)/kW ¼ (3600 s/hr)/(4.184 J/kcal)
Syngas replacement ratio (%, SRR) ¼ (diesel mass flow of diesel mode e diesel mass flow of dual fuel mode)/(diesel mass flow of diesel mode) *100% (4) 3. Results and discussion 3.1. Effect of temperature Fig. 2 shows the syngas composition, Xc, and CGE depending on the CWM-L gasification temperature. The CO content in the produced syngas increased with the gasification temperature, reaching 37.1% at 1190 C. On the other hand, the content of CO2 and CH4 in the syngas decreased as the gasification temperature increased, while the content of H2 remained constant. The key reactions affecting the composition of the syngas produced by coal gasification are represented by the following formulae [5,30,31].
DH ¼ 394 kJ mol1
Char combustion : C þ O2 ¼ CO2
Char partial oxidation : C þ 0:5O2 ¼ CO Water gas : C þ H2 O ¼ CO þ H 2 Methanation : C þ 2H 2 ¼ CH 4
DH ¼ 111 kJ mol1
DH ¼ 131 kJ mol1 DH ¼ 75 kJ mol1
Water gas shift : CO þ H2 O ¼ CO2 þ H 2 Methane reforming : CH 4 þ H 2 O ¼ CO þ 3H 2 Boudouard : C þ CO2 ¼ 2CO
DH ¼ 41 kJ mol1 DH ¼ 206 kJ mol1
DH ¼ 173 kJ mol1
(5) (6) (7) (8) (9) (10) (11)
The CWM supplied to the burner was atomized through contact with the gasification agent and then supplied to the gasifier. Subsequently, the CWM was conducted the oxidation and gasification reactions of Eqs. (5)e(7), and the produced gases further were carried out the reactions of Eqs. (8)e(11). Temperature affects not only the rate but also the equilibrium of each reaction. As the gasification temperature increased, the endothermic reactions, such as those of Eqs. (7), (10) and (11), were enhanced, but the exothermic reactions were suppressed, Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 2. Effect of temperature on gasification of CWM-L.
influencing the composition of the syngas. Therefore, explanation of the variation of the syngas composition requires a consideration of the enthalpy, the reactants, and the products in Eqs. (5)e(11). Considering the increase of the CO content and the decrease of the CO2 content in the syngas, as shown in Fig. 2, in addition to the gasification reactions of Eqs. (5)e(7), the reactions that affected the content of CO and CO2 with the increase of the gasification temperature should be endothermic reactions. In addition, since the H2 content in the syngas remained constant, the reactions should have no effect on the H2 content. Among the reactions represented by Eqs. (8)e(11), the reaction that meets the above conditions is the Boudouard reaction of Eq. (11). Therefore, the variation of the syngas composition shown in Fig. 2 may have been affected by the oxidation and gasification reactions of Eqs. (5)e(7), as well as by the Boudouard reaction. The contents of CO, CH4, and CO2 in the syngas, which affect Xc in Fig. 2, either increased or decreased. However, as the syngas flow rate increased due to the increase of the gasification temperature, Xc also increased. In addition, as the flow rates of H2 and CO, the combustible components, increased and the content of CO2, a non-combustible component in the syngas, decreased, the CGE increased with the increase of the gasification temperature, reaching 66.1% at 1190 C. 3.2. Effect of equivalence ratio Fig. 3 shows the results of CWM-L gasification depending on the ER. As the ER increased, the contents of H2 and CH4 in the produced syngas decreased, reaching 28.6% and 0.4%, respectively, at the ER of 0.51. In contrast, the CO content increased to 38.4% until the ER was 0.47, Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 3. Effect of equivalence ratio on gasification of CWM-L.
and then remained almost constant. The CO2 content in the syngas decreased until the ER increased to 0.43, and then started to increase. The minimum CO2 content was 26.8% at the ER of 0.43. Xc increased with the increase of the ER due to the increase of the CO content in the syngas and the variation of the CO2 production. Xc at the ER of 0.51 was 91.1%. However, due to the decrease of the H2 content and the increase of the CO content in the produced syngas, the CGE increased with the increase of ER up to the ER of 0.43and reached a maximum of 66.1%. The increase of the ER due to the increase of the O2 supply enhanced the oxidation reactions, such as those of Eqs. (5) and (6), producing thermal energy. Thus, the increase of the ER caused the increase of the gasifier temperature, which resulted in increases of Xc and CGE, as shown in Fig. 2. However, when the ER was close to 1, conditions for combustion were formed, resulting in the production of CO2 rather than the production of H2 and CO, the combustible components in the syngas. Therefore, while Xc increased with the increase of the ER, CGE showed a maximum value due to combination of the gasification temperature, the composition of the produced syngas, and the flow rate of the produced syngas.
3.3. Comparison of CWM-H and L gasification Fig. 4 shows the entrained-flow gasification results for CWM-H and L at a constant ER of 0.41. The CO contents in the syngas of the CWMH and L gasification were 37.1% and 32.7%, respectively, showing a difference of 4.4%. The H2 content in the CWM-L gasification syngas was 36.8%, which was higher than that of CWM-H. The CH4 content in the CWM-L gasification syngas was 1.8%, which was two times higher than Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 4. Comparison of gasification performance on CWM-H and CWM-L (ER 0.41).
that of CWM-H. The CO2 content was also higher in the CWM-L gasification syngas. The Xc of the CWM-H and L were 84.6 and 82.1%, respectively, and the CGE were 61.36% and 60.6%, respectively. Hence, the Xc and CGE, representing the gasification efficiency, were higher in the CWM-H gasification. The water contained in the CWM was supplied with coal to the gasifier and absorbed the heat in the gasifier. The CWM, having a relatively low coal concentration, had a high water content. Thus, the gasification temperatures of CWM-H and L, shown in Fig. 4 under the same operation conditions, were different at 1151 C and 1115 C, respectively. From this temperature difference, CWM-H with high gasification temperature showed higher Xc and CGE than CWM-L. On the other hand, the water contained in the CWM was consumed in the endothermic reactions (Eqs. (7) and (10)) and exothermic reactions (Eq. (9)) in the gasifier, and the increase in the amount of water affected the equilibrium of Eqs. (7), (9) and (10) by the increase of the reactant. The H2/CO ratios of the syngas produced by the CWM-H and L gasification were different at 0.97 and 1.13, respectively, and the CO2 contents were also different. Hence, the contents of H2, CO, and CO2 in the gasification syngas were affected by the CWM concentration. Considering the high H2 and CO2 contents and the low CO content in the CWM-L, which has a relatively higher water content than CWM-H, the composition of the syngas was considered to affect by the water gas shift reaction of Eq. (9). The H2/CO ratio is an important factor in the production processes of hydrogen, methanol, dimethyl ether (DME), etc. using syngas [32,33]. According to the results shown in Fig. 4, it is possible to produce syngas with an H2/CO ratio suitable for a syngas application process through the CWM concentration control. Thus, the CWM concentration during the gasification operation is a key parameter for gasification, together with the ER. However, since a decrease of the CWM concentration causes a decrease of Xc and CGE, optimization is required with regard to the process. 3.4. Effect of feed flow rate on gasification After the CWM is injected in the burner, the CWM supplied to the gasifier is atomized by the gasification agent. Atomized CWM, having an increased specific surface area, enhances the gasification reactions [34]. Hence, the variation of the flow rate of the gasification agent affects the CWM atomization, resulting in a change in the gasification reaction. Fig. 5 shows the results of CWM-H gasification with varying feed (O2 þ N2) flow by addition of N2 at ER of 0.31 to verify the effect of the gasification agent flow rate variation. As the feed flow rate increased from 21 to 31 Nm3/h, the contents of H2, CO, and CO2 in the produced syngas were found to decrease due to the added N2. On the contrary, the content of CH4 increased. The flow rate of the produced syngas increased as N2 was additionally supplied. The flow rate of the syngas produced in the feed flow rate range of 21e28 Nm3/h increased by 10 Nm3/h, which was greater than the flow rate of the additionally supplied N2. Due to the changes of the composition and flow rate of the produced syngas, Xc and CGE showed maximum values of 61.7 and 47.7%, respectively, at the feed flow rate of 28 Nm3/h. In Fig. 6, gasification of CWM-L at a constant ER of 0.44 was Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 5. Effect of feed flow rate on gasification of CWM-H (ER 0.31).
Fig. 6. Effect of feed flow rate on gasification of CWM-L (ER 0.44).
performed to verify the effect of the feed flow rate change at different ER and CWM concentrations. As the feed flow rate increased, the CO content in the produced syngas decreased, and the contents of H2 and CO2 changed slightly. The flow rate of the produced syngas increased with the feed flow rate. The increase of the syngas flow rate in the feed flow rate range of 28e34 Nm3/h was 7.4 Nm3/h, which was greater than that of the flow rate of the additionally supplied N2. However, in the feed flow rate range of 34e37 Nm3/h, the increase of the syngas flow rate was 1.7 Nm3/h, which was smaller than the flow rate of the additionally supplied N2. Due to the variation of the composition and flow rate of the produced syngas, the Xc and CGE showed maximum values of 90.4% and 65.1%, respectively, at the feed flow rate of 34 Nm3/h. The increase of the feed flow rate was found to enhance the CWM atomization and produce smaller droplets [34,35], which increased Xc and CGE [12,36]. However, the increase of the feed flow rate decreased the residence time of the CWM in the gasifier due to the high flow rate. In addition, the inflow of a colder gas in comparison with the gasifier temperature increased, and the injected N2, which does not participate in the reactions but takes thermal energy away from the gasifier, decreased the gasifier temperature [12,26]. The decrease of the CWM residence time and the gasification temperature reduced Xc and CGE. Therefore, the gasification results shown in Figs. 5 and 6 reflect both the positive and negative effects of the increase of the feed flow rate, indicating that an optimum feed flow rate exists depending on the CWM concentration and the ER.
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 7. Effect of syngas flow rate on modified diesel engine.
3.5. Application of syngas to dual-fuel diesel engine Fig. 7 shows the results of the application of the syngas produced by CWM-L gasification to a modified dual-fuel diesel engine. While operating the engine under a constant gasification condition of ER 0.44, the syngas was supplied at the constant composition of H2 28.1%, CO 36%, CH4 0.3%, and CO2 35.1%. As shown in Fig. 7, despite the increase of the feed flow rate of the syngas injected into the engine, the BTE at the operation conditions of 26 kW and 40 kW were not significantly change at 24.8% and 34%, respectively. As the syngas feed flow rate increased, the SRR continuously increased due to the syngas replacing diesel, but the BTE remained constant regardless of the increase of the SRR under the constant operation conditions of 26 kW and 40 kW. The BTE was higher in the operation at 40 kW than it was at 26 kW, indicating that the BTE in dual-fuel mode was higher at a higher load [20,28]. In the operation at 26 kW, until the syngas feed flow rate increased to 21 Nm3/h, the SRR was lower than that of the operation at 40 kW, but the highest SRR of 63.3% was found at 26 Nm3/h. A similar result was reported by Sahoo et al. [28], in which the SRR increased with the increase of the engine load, but then decreased after showing a maximum value at a specific load. Thus, an appropriate engine load is required, when a high SRR is required to reduce the diesel consumption and to increase the syngas consumption. As found in Figs. 2e6, the flow rate of the syngas, which affects the SRR, is determined by the gasification conditions including the temperature, CWM concentration and the ER. The composition of the syngas is also determined by the gasification conditions. Hernandez et al. [20] determined the effects that change of contents of H2, CO, and CH4 had on the BTE. Thus, gasification conditions enabling the control of the syngas composition and flow rate should be considered for efficient dual-fuel operation of a diesel engine. Therefore, efficient power generation through entrainedflow gasification requires the optimization of gasification operation, considering not only the gasification efficiency but also the efficiency of the modified dual-fuel diesel engine operation. 4. Conclusion CWMs prepared at different concentrations were gasified through entrained-flow gasifier under various operation conditions. The produced syngas was applied to a modified diesel engine to investigate the power generation from the syngas. As the gasification conditions were varied, the composition of the produced syngas was affected by the Boudouard reaction. The CGE showed a maximum of 66.1% at an ER of 0.43, while Xc was seen to increase with the increase of the ER. The difference in composition of syngas, Xc, and CGE was found for gasification of CWM-H and CWM-L. The gasification of CWM-H showed lower H2/CO ratio, however, higher Xc and CGE than CWM-L. The effect of the feed flow rate was investigated by additionally supplying N2 at a constant ER. In the gasification of CWM-H at the ER of 0.31, Xc Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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and CGE showed maximum values at the gasification agent flow rate of 28 Nm3/h. In the gasification of CWM-L at the ER of 0.44, Xc and CGE showed maximum values of 90.4% and 65.1%, respectively, at the feed flow rate of 34 Nm3/h. The produced syngas was applied to a dual-fuel diesel engine. The BTE remained almost constant despite changes in the flow rate of the syngas injected into the engine. A maximum BTE of 35.1% was found in the operation at 40 kW. The SRR increased with syngas feed flow rate and reached 63.3% at 26 kW. The dual-fuel operation of the diesel engine was found to be dependent on the flow rate of the syngas as well as on the engine load. Thus, entrainedflow gasification operation for power generation requires a determination of the gasification conditions considering both gasification efficiency and diesel engine operation. In the present study, the potential of efficient power generation was verified through a hydrogen-rich syngas production by gasification of CWM and the dual-fuel operation of a diesel engine with syngas. Acknowledgements This research was supported by the Energy Technology Development project of the Ministry of Trade, Industry and Energy in Republic of KOREA (20143030050060). Appendix A. Supplementary data Supplementary data related to this article can be found at https://doi.org/10.1016/j.joei.2018.01.009. References
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mez-Barea, B. Leckner, Modeling of biomass gasification in fluidized bed, Prog. Energy Combust. Sci. (2010), https://doi.org/10.1016/j.pecs.2009.12.002. [1] A. Go [2] K.Y. Koo, H.-S. Roh, U.H. Jung, W.L. Yoon, Combined H2O and CO2 reforming of CH4 over Ce-promoted Ni-Al2O3 catalyst for gas to liquid (GTL) process- enhancement of NieCeO2 interaction, Catal. Today 185 (2012) 126e130, https://doi.org/10.1016/j.cattod.2011.07.027. [3] S.Y. Park, G. Oh, K. Kim, M.W. Seo, H.W. Ra, T.Y. Mun, J.G. Lee, S.J. Yoon, Deactivation characteristics of Ni and Ru catalysts in tar steam reforming, Renew. Energy 105 (2017) 76e83, https://doi.org/10.1016/j.renene.2016.12.045. [4] S. Chen, A. Meng, Y. Long, H. Zhou, Q. Li, Y. Zhang, TGA pyrolysis and gasification of combustible municipal solid waste, J. Energy Inst. 88 (2015) 332e343, https://doi.org/ 10.1016/j.joei.2014.07.007. [5] J.I. Na, S.J. Park, Y.K. Kim, J.G. Lee, J.H. Kim, Characteristics of oxygen-blown gasification for combustible waste in a fixed-bed gasifier, Appl. Energy 75 (2003) 275e285, https://doi.org/10.1016/S0306-2619(03)00041-2. [6] T. Chmielniak, M. Sciazko, Co-gasification of biomass and coal for methanol synthesis, Appl. Energy 74 (2003) 393e403, https://doi.org/10.1016/S0306-2619(02)00184-8. [7] K. Qin, W. Lin, S. Faster, P.A. Jensen, H. Wu, A.D. Jensen, Characterization of residual particulates from biomass entrained flow gasification, Energy and Fuels 27 (2013) 262e270, https://doi.org/10.1021/ef301432q. [8] A.D. Lewis, T.M. Holland, N.R. Marchant, E.G. Fletcher, D.J. Henley, E.G. Fuller, T.H. Fletcher, Steam gasification rates of three bituminous coal chars in an entrained-flow reactor at pressurized conditions, Energy and Fuels 29 (2015) 1479e1493, https://doi.org/10.1021/ef502608y. [9] A.H. Tchapda, S.V. Pisupati, Characterization of an entrained flow reactor for pyrolysis of coal and biomass at higher temperatures, Fuel 156 (2015) 254e266, https:// doi.org/10.1016/j.fuel.2015.04.015. [10] J. Billaud, S. Valin, M. Peyrot, S. Salvador, Influence of H2O, CO2 and O2 addition on biomass gasification in entrained flow reactor conditions: experiments and modelling, Fuel 166 (2016) 166e178, https://doi.org/10.1016/j.fuel.2015.10.046. [11] S. Chaiklangmuang, K. Kurosawa, L. Li, K. Morishita, T. Takarada, Thermal degradation behavior of coffee residue in comparison with biomasses and its product yields from gasification, J. Energy Inst. 88 (2015) 323e331, https://doi.org/10.1016/j.joei.2014.08.001. [12] S.J. Yoon, Y.C. Choi, Y. Il Son, S.H. Lee, J.G. Lee, Gasification of biodiesel by-product with air or oxygen to make syngas, Bioresour. Technol. 101 (2010) 1227e1232, https:// doi.org/10.1016/j.biortech.2009.09.039. [13] S.H. Lee, S.J. Yoon, H.W. Ra, Y. Il Son, J.C. Hong, J.G. Lee, Gasification characteristics of coke and mixture with coal in an entrained-flow gasifier, Energy 35 (2010) 3239e3244, https://doi.org/10.1016/j.energy.2010.04.007. [14] P. Feng, W. Lin, P.A. Jensen, W. Song, L. Hao, K. Raffelt, K. Dam-Johansen, Entrained flow gasification of coal/bio-oil slurries, Energy 111 (2016) 793e802, https://doi.org/ 10.1016/j.energy.2016.05.115. [15] I. Adeyemi, I. Janajreh, Modeling of the entrained flow gasification: kinetics-based ASPEN Plus model, Renew. Energy 82 (2015) 77e84, https://doi.org/10.1016/ j.renene.2014.10.073. [16] M. Saiful Alam, A.T. Wijayanta, K. Nakaso, J. Fukai, Study on coal gasification with soot formation in two-stage entrained-flow gasifier, Int. J. Energy Environ. Eng. 6 (2015) 255e265, https://doi.org/10.1007/s40095-015-0173-1. [17] M.B. Tilghman, R.E. Mitchell, Impact of Co-firing coal and biomass on mixed char reactivity under gasification conditions, Energy and Fuels 30 (2016) 1708e1719, https:// doi.org/10.1021/acs.energyfuels.5b02480. [18] S. Xu, Y. Ren, B. Wang, Y. Xu, L. Chen, X. Wang, T. Xiao, Development of a novel 2-stage entrained flow coal dry powder gasifier, Appl. Energy 113 (2014) 318e323, https:// doi.org/10.1016/j.apenergy.2013.07.045. [19] J. Tanner, S. Bhattacharya, Kinetics of CO2 and steam gasification of Victorian brown coal chars, Chem. Eng. J. 285 (2016) 331e340, https://doi.org/10.1016/ j.cej.2015.09.106. ndez, M. Lapuerta, J. Barba, Separate effect of H2, CH4 and CO on diesel engine performance and emissions under partial diesel fuel replacement, Fuel 165 (2016) [20] J.J. Herna 173e184, https://doi.org/10.1016/j.fuel.2015.10.054. ndez, M. Lapuerta, J. Barba, Effect of partial replacement of diesel or biodiesel with gas from biomass gasification in a diesel engine, Energy 89 (2015) 148e157, [21] J.J. Herna https://doi.org/10.1016/j.energy.2015.07.050. [22] A.L. Boehman, O. Le Corre, Combustion of syngas in internal combustion engines, Combust. Sci. Technol. 180 (2008) 1193e1206, https://doi.org/10.1080/ 00102200801963417. [23] G. Diaz, V.A. Kuznetsov, I.I. Kumkova, A.N. Bratsev, I.I. Kumkova, Experimental Study on the Effect of Varying Syngas Composition on the Emissions of Dual Fuel CI Engine Operating at Various Engine Speeds, IOP Conf. Series: Mater. Sci. Eng. 100, 2015, https://doi.org/10.1088/1757-899X/100/1/012006, 012006. [24] F. Christodoulou, A. Megaritis, The effect of reformer gas mixture on the performance and emissions of an HSDI diesel engine, Int. J. Hydrogen Energy 39 (2014) 9798e9808, https://doi.org/10.1016/j.ijhydene.2014.03.090. [25] Y.C. Choi, X.Y. Li, T.J. Park, J.H. Kim, J.G. Lee, Numerical study on the coal gasification characteristics in an entrained flow coal gasifier, Fuel 80 (2001) 2193e2201, https:// doi.org/10.1016/S0016-2361(01)00101-6. [26] S.J. Yoon, Y.M. Yun, M.W. Seo, Y.K. Kim, H.W. Ra, J.G. Lee, Hydrogen and syngas production from glycerol through microwave plasma gasification, Int. J. Hydrogen Energy 38 (2013) 14559e14567, https://doi.org/10.1016/j.ijhydene.2013.09.001. [27] N. Kobayashi, M. Tanaka, G. Piao, J. Kobayashi, S. Hatano, Y. Itaya, S. Mori, High temperature air-blown woody biomass gasification model for the estimation of an entrained down-flow gasifier, Waste Manag. 29 (2009) 245e251, https://doi.org/10.1016/j.wasman.2008.04.014. [28] B.B. Sahoo, N. Sahoo, U.K. Saha, Effect of H2:CO ratio in syngas on the performance of a dual fuel diesel engine operation, Appl. Therm. Eng. 49 (2012) 139e146, https:// doi.org/10.1016/j.applthermaleng.2011.08.021. [29] S. Sugiyama, N. Suzuki, Y. Kato, K. Yoshikawa, A. Omino, T. Ishii, K. Yoshikawa, T. Kiga, Gasification performance of coals using high temperature air, Energy 30 (2005) 399e413, https://doi.org/10.1016/j.energy.2004.06.001. [30] F. Guo, Y. Dong, L. Dong, C. Guo, Effect of design and operating parameters on the gasification process of biomass in a downdraft fixed bed: an experimental study, Int. J. Hydrogen Energy 39 (2014) 5625e5633, https://doi.org/10.1016/j.ijhydene.2014.01.130.
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[31] G. Oh, S.Y. Park, M.W. Seo, Y.K. Kim, H.W. Ra, J.G. Lee, S.J. Yoon, Ni/Ru-Mn/Al2O3 catalysts for steam reforming of toluene as model biomass tar, Renew. Energy 86 (2016) 841e847, https://doi.org/10.1016/j.renene.2015.09.013. [32] G.A. Olah, A. Goeppert, M. Czaun, T. Mathew, R.B. May, G.K.S. Prakash, Single step Bi-reforming and oxidative Bi-reforming of methane (natural gas) with steam and carbon dioxide to metgas (CO-2H2) for methanol synthesis: self-sufficient effective and exclusive oxygenation of methane to methanol with oxygen, J. Am. Chem. Soc. 137 (2015) 8720e8729, https://doi.org/10.1021/jacs.5b02029. rez-Uriarte, M. Sa nchez-Contador, J. Eren ~ a, A.T. Aguayo, J. Bilbao, Direct synthesis of dimethyl ether from syngas on CuOZnOMnO/SAPO-18 bifunctional [33] A. Ateka, P. Pe catalyst, Int. J. Hydrogen Energy 41 (2016) 18015e18026, https://doi.org/10.1016/j.ijhydene.2016.07.195. [34] Y. Hai-long, Z. Chao, L. Jian-zhong, C. Ke-fa, Experimental study of the atomizing performance of a new type of nozzle for coal water slurry, Energy and Fuels 22 (2008) 1170e1173, https://doi.org/10.1021/ef700553s. [35] Z. Yan, Q. Liang, Q. Guo, G. Yu, Z. Yu, Experimental investigations on temperature distributions of flame sections in a bench-scale opposed multi-burner gasifier, Appl. Energy 86 (2009) 1359e1364, https://doi.org/10.1016/j.apenergy.2008.09.020. [36] T. Jakobs, N. Djordjevic, S. Fleck, M. Mancini, R. Weber, T. Kolb, Gasification of high viscous slurry R&D on atomization and numerical simulation, Appl. Energy 93 (2012) 449e456, https://doi.org/10.1016/j.apenergy.2011.12.026.
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Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine Q4
Gunung Oh a, Ho Won Ra b, Sung Min Yoon b, Tae Young Mun b, Myung Won Seo b, Jae-Goo Lee a, c, Sang Jun Yoon a, b, * a b c
Advanced Energy Technology, Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea Climate Change Research Division, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea Future Energy Plant Convergence Research Center, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history: Received 26 July 2017 Received in revised form 16 January 2018 Accepted 16 January 2018 Available online xxx
In the present study, a syngas was produced by preparing coal water mixtures of two different concentrations and gasifying the coal water mixtures. An entrained-flow gasifier of 1 ton/day scale was used and, after undergoing a purification process, the produced syngas was applied to a modified diesel engine for power generation. As the gasification temperature increased, the carbon conversion and the cold gas efficiency were found to increase. In the composition of the produced syngas, the content of H2 remained constant, that of CO increased, and those of CO2 and CH4 decreased. The carbon conversion increased with equivalence ratio. A maximum cold gas efficiency of 66.1% was found at the equivalence ratio of 0.43. N2 was additionally supplied to verify the gasification characteristics depending on the gas feed flow rate. The optimum feed flow rate was verified at different slurry concentrations and equivalence ratio. The produced syngas was supplied to a modified diesel engine and operated depending on the syngas feed flow rate and the engine operation conditions. The brake thermal efficiency of the engine was constant regardless of the syngas feed flow rate. The diesel engine showed high efficiency despite the mixing of the syngas. © 2018 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Keywords: Gasification Entrained-flow Coal water mixture Feed flow rate Dual-fuel Diesel engine
1. Introduction The climate change is drawing international attention, and CO2 is considered the major cause of climate change [1]. Hence, to reduce CO2 emission, studies have been continuously conducted for highly efficient and clean utilization of fossil fuels, which are the main sources of carbon emission [2]. Gasification has been studied as one technology to accomplish the highly efficient and clean utilization of fossil fuels. Gasification is a thermochemical technology for producing a syngas containing H2 and CO through a thermochemical reaction of coal, biomass, and other fuels. The produced syngas may be applied to the generation of electric power and as a raw material of chemicals [3,4]. Gasification has advantages over traditional combustion, including less discharge of pollutant, and high thermal efficiency [5,6]. Gasifiers are classified into fixed bed, fluidized bed, and entrained-flow gasifiers. In particular, entrained-flow gasifiers, having a high carbon conversion and a high efficiency, are used in such processes as integrated gasification combined cycle (IGCC) [7e9]. Various fuels, such as coal, biomass [10,11], glycerin [12], coke [13], and bio-oil [14], have been studied as fuels for entrained-flow gasification, and gasification for waste treatment has also been conducted [15]. Among these fuels, coal is extensively used because it is widely available and its reserves are plentiful, and coal consumption is expected to continue into the future [16,17]. With regard to entrained-flow gasification of coal, studies have been conducted on gasifiers [18] as well as on gasification agents and gasification kinetics [19]. Coal supply modes in entrained-flow gasification include dry feeding and slurry feeding. Dry feeding, in which coal powder is supplied to a gasifier, gives a high cold gas efficiency and a high carbon conversion and, compared with slurry feeding, allows users to utilize more various types of coal [18]. On the contrary, in slurry feeding, in which coal is supplied as a coal water mixture (CWM), the transportation is
* Corresponding author. Advanced Energy Technology, Korea University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea. E-mail address: [email protected] (S.J. Yoon). https://doi.org/10.1016/j.joei.2018.01.009 1743-9671/© 2018 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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convenient and the pressurization for the gasification reaction is easily performed due to the liquid-like characteristics of CWM. In addition, slurry feeding may prevent scattering and spontaneous ignition of the raw material, enhancing the operational safety. Since the water contained in the CWM is a reactant, the syngas composition and the gasification efficiency were adjusted by varying the CWM concentration. Air and oxygen are commonly used as gasification agents for entrained-flow gasifiers. Air-blown gasification enables a saving of installation and operation costs because it does not require an air separation unit (ASU) for oxygen separation [12]. However, due to the N2 contained in the produced syngas, the heating value of the syngas decreases, and a large purification facility is required. However, oxygenblown gasification shows a higher carbon conversion and cold gas efficiency in comparison with air-blown gasification. In addition, since almost no N2 is injected, little NOx is generated, and CO2 capture from the produced syngas is easier than it is for air-blown gasification. Electric power generation using a produced syngas requires a gas turbine, a gas engine, or a steam turbine depending on the scale. With regard to small and middle-scale power generation, studies are being conducted on not only gas engines but also diesel engines using a mixture of diesel and syngas. Utilization of a mixture of diesel and syngas results in higher efficiency and less generation of NOx, CO2, and particulate matter (PM) in comparison with gas engines [20e22]. Studies have been conducted on various types of diesel engines, such as compression ignition (CI) [23] and high speed direct injection (HSDI) [24], usually using a simulation syngas. While the composition and the flow rate of syngas are dependent on such gasification conditions as slurry concentration, equivalence ratio, and temperature, few studies have been conducted on diesel engines in relation to the variation of these conditions. Therefore, studies should be conducted on the actual application of a syngas produced from a gasifier to a diesel engine for the application to a commercial gasification plant. In the present study, CWM of different concentrations were prepared and gasified in a 1 ton/day scale entrained-flow gasification plant. The syngas produced from the gasification was applied to a modified diesel engine for power generation. The gasification of CWM was conducted by varying the gasification conditions, including the temperature, equivalence ratio, and feed flow rate. To investigate the effect of the CWM concentration on the H2/CO ratio, the syngas composition and gasification efficiency depending on the CWM concentration difference were compared. In addition, the produced syngas was used together with diesel in dual-fuel mode in a modified diesel engine, and the characteristics of the dual-fuel engine operation were also measured. 2. Experimental 2.1. Coal water mixture Table 1 shows the results of the proximate, ultimate, and heating value analysis of the coal used for the preparation of the coal water mixture (CWM). The coal was pulverized into a powder having a size of about 75 mm, which was then mixed with a surfactant (Sikament NN, Sika Korea) and water. To verify the effect on gasification depending on slurry concentration, two types of slurry having different coal concentrations, with carbon/H2O molar ratios of 1.35 (CWM-H, 57.1 wt%) and 1.22 (CWM-L, 54.6 wt%), were prepared with same surfactant. 2.2. Entrained-flow gasification system Fig. 1 is a schematic diagram of the entrained-flow gasifier of 1 ton/day scale used in the present study. Coal and water were mixed in a slurry tank to prepare the CWM, which was then quantitatively supplied using a mono-pump (4B-20, MONAS). The CWM was sprayed into the gasifier through the central hole of a burner attached to the top of the gasifier, and then atomized by contacting the O2 and N2 sprayed from eight holes around the central hole [25]. The O2 and N2 used for the experiment were supplied using a mass flow controller (MFC, Smart mass flow 5853S, BROOKS). The internal diameter and height of the gasifier were 250 mm and 1700 mm, respectively. Three R-type thermocouples were installed to measure the internal temperature distribution. Refractory and insulation materials were used to protect and insulate the gasifier. A K-type thermocouple was installed to monitor the temperature of the refractory and the insulation materials. The ash and slag remaining after the gasification were cooled through contact with the coolant at the bottom of the gasifier, moved to the lockhopper at the bottom of the gasifier, and then discharged. The flow rate of the syngas produced from the gasifier was measured using a vortex flow meter (KODS-KV-01, OVAL KOREA LIMITED), and the composition of syngas was measured using an IR gas analyzer (AO2020, ABB) and a thermal conductivity detector (TCD, carbosphere 80/100 packed column, Alltech) of a gas chromatography (7890A, Agilent). After going through a wet scrubber, a desulfurization unit, and a filter, the syngas was combusted in a dual-fuel engine and a flare stack. According to the experimental conditions, the syngas was injected into a gas mixer using a valve, mixed with the air, and then injected into the diesel engine. The syngas feed flow rate is measured by a vortex flow meter (KODS-KV-01, OVAL KOREA LIMITED), which is installed before gas mixer. The direct injection type diesel engine used in the experiment (D1146T, Doosan Commercial Engine) had a maximum power of 130 kW, and was operated at a constant rate of 1800 rpm using diesel and the syngas produced from the gasifier. The power generation was set at 26 or 40 kW using a resistive load bank. The quantity of injected diesel was automatically controlled by an electronic control unit (ECU) so that the engine could be operated at a constant rate at 1800 rpm. For the preheating of the gasifier, the temperature was raised to 1000 C using LNG. Then, CWM, O2, and N2 were supplied to vary the equivalence ratio (ER) from 0.35 to 0.53. O2 and N2 were supplied at flow rates of 21e30 and 9e12 Nm3/h, respectively, according to the experimental conditions. The carbon conversion (Xc) and cold gas efficiency (CGE) of the gasification, and the brake thermal efficiency (BTE) and syngas replacement ratio (SRR) of the engine, were calculated using the following equations [26e29]: Carbon conversion (%, Xc) ¼ (mass flow of carbon in the syngas)/(mass flow of carbon in the feedstock)*100%
(1)
Table 1 Properties of coal. Fuel
Proximate analysis (Air dry basis), wt%
Ultimate analysis (Dry basis), wt%
HHV (kcal/kg)
Moisture
Volatile
Ash
Fixed carbon
C
H
O
N
S
Coal
6.37
29.2
13.47
50.99
72.1
4.13
8.75
1.51
0.04
6,220
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 1. Schematic diagram of entrained-flow gasification system.
Cold gas efficiency (%, CGE) ¼ ( *100%
P mass flow of H2, CO, CH4*heating value of H2, CO, CH4)/(heating value of feedstock*mass flow of feedstock) (2)
Brake thermal efficiency (%, BTE) ¼ (engine power output)/(
P mass flow of fuel*heating value of fuel)*860 (kcal/hr)/kW*100%
(3)
860 (kcal/hr)/kW ¼ (3600 s/hr)/(4.184 J/kcal)
Syngas replacement ratio (%, SRR) ¼ (diesel mass flow of diesel mode e diesel mass flow of dual fuel mode)/(diesel mass flow of diesel mode) *100% (4) 3. Results and discussion 3.1. Effect of temperature Fig. 2 shows the syngas composition, Xc, and CGE depending on the CWM-L gasification temperature. The CO content in the produced syngas increased with the gasification temperature, reaching 37.1% at 1190 C. On the other hand, the content of CO2 and CH4 in the syngas decreased as the gasification temperature increased, while the content of H2 remained constant. The key reactions affecting the composition of the syngas produced by coal gasification are represented by the following formulae [5,30,31].
DH ¼ 394 kJ mol1
Char combustion : C þ O2 ¼ CO2
Char partial oxidation : C þ 0:5O2 ¼ CO Water gas : C þ H2 O ¼ CO þ H 2 Methanation : C þ 2H 2 ¼ CH 4
DH ¼ 111 kJ mol1
DH ¼ 131 kJ mol1 DH ¼ 75 kJ mol1
Water gas shift : CO þ H2 O ¼ CO2 þ H 2 Methane reforming : CH 4 þ H 2 O ¼ CO þ 3H 2 Boudouard : C þ CO2 ¼ 2CO
DH ¼ 41 kJ mol1 DH ¼ 206 kJ mol1
DH ¼ 173 kJ mol1
(5) (6) (7) (8) (9) (10) (11)
The CWM supplied to the burner was atomized through contact with the gasification agent and then supplied to the gasifier. Subsequently, the CWM was conducted the oxidation and gasification reactions of Eqs. (5)e(7), and the produced gases further were carried out the reactions of Eqs. (8)e(11). Temperature affects not only the rate but also the equilibrium of each reaction. As the gasification temperature increased, the endothermic reactions, such as those of Eqs. (7), (10) and (11), were enhanced, but the exothermic reactions were suppressed, Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 2. Effect of temperature on gasification of CWM-L.
influencing the composition of the syngas. Therefore, explanation of the variation of the syngas composition requires a consideration of the enthalpy, the reactants, and the products in Eqs. (5)e(11). Considering the increase of the CO content and the decrease of the CO2 content in the syngas, as shown in Fig. 2, in addition to the gasification reactions of Eqs. (5)e(7), the reactions that affected the content of CO and CO2 with the increase of the gasification temperature should be endothermic reactions. In addition, since the H2 content in the syngas remained constant, the reactions should have no effect on the H2 content. Among the reactions represented by Eqs. (8)e(11), the reaction that meets the above conditions is the Boudouard reaction of Eq. (11). Therefore, the variation of the syngas composition shown in Fig. 2 may have been affected by the oxidation and gasification reactions of Eqs. (5)e(7), as well as by the Boudouard reaction. The contents of CO, CH4, and CO2 in the syngas, which affect Xc in Fig. 2, either increased or decreased. However, as the syngas flow rate increased due to the increase of the gasification temperature, Xc also increased. In addition, as the flow rates of H2 and CO, the combustible components, increased and the content of CO2, a non-combustible component in the syngas, decreased, the CGE increased with the increase of the gasification temperature, reaching 66.1% at 1190 C. 3.2. Effect of equivalence ratio Fig. 3 shows the results of CWM-L gasification depending on the ER. As the ER increased, the contents of H2 and CH4 in the produced syngas decreased, reaching 28.6% and 0.4%, respectively, at the ER of 0.51. In contrast, the CO content increased to 38.4% until the ER was 0.47, Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 3. Effect of equivalence ratio on gasification of CWM-L.
and then remained almost constant. The CO2 content in the syngas decreased until the ER increased to 0.43, and then started to increase. The minimum CO2 content was 26.8% at the ER of 0.43. Xc increased with the increase of the ER due to the increase of the CO content in the syngas and the variation of the CO2 production. Xc at the ER of 0.51 was 91.1%. However, due to the decrease of the H2 content and the increase of the CO content in the produced syngas, the CGE increased with the increase of ER up to the ER of 0.43and reached a maximum of 66.1%. The increase of the ER due to the increase of the O2 supply enhanced the oxidation reactions, such as those of Eqs. (5) and (6), producing thermal energy. Thus, the increase of the ER caused the increase of the gasifier temperature, which resulted in increases of Xc and CGE, as shown in Fig. 2. However, when the ER was close to 1, conditions for combustion were formed, resulting in the production of CO2 rather than the production of H2 and CO, the combustible components in the syngas. Therefore, while Xc increased with the increase of the ER, CGE showed a maximum value due to combination of the gasification temperature, the composition of the produced syngas, and the flow rate of the produced syngas.
3.3. Comparison of CWM-H and L gasification Fig. 4 shows the entrained-flow gasification results for CWM-H and L at a constant ER of 0.41. The CO contents in the syngas of the CWMH and L gasification were 37.1% and 32.7%, respectively, showing a difference of 4.4%. The H2 content in the CWM-L gasification syngas was 36.8%, which was higher than that of CWM-H. The CH4 content in the CWM-L gasification syngas was 1.8%, which was two times higher than Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 4. Comparison of gasification performance on CWM-H and CWM-L (ER 0.41).
that of CWM-H. The CO2 content was also higher in the CWM-L gasification syngas. The Xc of the CWM-H and L were 84.6 and 82.1%, respectively, and the CGE were 61.36% and 60.6%, respectively. Hence, the Xc and CGE, representing the gasification efficiency, were higher in the CWM-H gasification. The water contained in the CWM was supplied with coal to the gasifier and absorbed the heat in the gasifier. The CWM, having a relatively low coal concentration, had a high water content. Thus, the gasification temperatures of CWM-H and L, shown in Fig. 4 under the same operation conditions, were different at 1151 C and 1115 C, respectively. From this temperature difference, CWM-H with high gasification temperature showed higher Xc and CGE than CWM-L. On the other hand, the water contained in the CWM was consumed in the endothermic reactions (Eqs. (7) and (10)) and exothermic reactions (Eq. (9)) in the gasifier, and the increase in the amount of water affected the equilibrium of Eqs. (7), (9) and (10) by the increase of the reactant. The H2/CO ratios of the syngas produced by the CWM-H and L gasification were different at 0.97 and 1.13, respectively, and the CO2 contents were also different. Hence, the contents of H2, CO, and CO2 in the gasification syngas were affected by the CWM concentration. Considering the high H2 and CO2 contents and the low CO content in the CWM-L, which has a relatively higher water content than CWM-H, the composition of the syngas was considered to affect by the water gas shift reaction of Eq. (9). The H2/CO ratio is an important factor in the production processes of hydrogen, methanol, dimethyl ether (DME), etc. using syngas [32,33]. According to the results shown in Fig. 4, it is possible to produce syngas with an H2/CO ratio suitable for a syngas application process through the CWM concentration control. Thus, the CWM concentration during the gasification operation is a key parameter for gasification, together with the ER. However, since a decrease of the CWM concentration causes a decrease of Xc and CGE, optimization is required with regard to the process. 3.4. Effect of feed flow rate on gasification After the CWM is injected in the burner, the CWM supplied to the gasifier is atomized by the gasification agent. Atomized CWM, having an increased specific surface area, enhances the gasification reactions [34]. Hence, the variation of the flow rate of the gasification agent affects the CWM atomization, resulting in a change in the gasification reaction. Fig. 5 shows the results of CWM-H gasification with varying feed (O2 þ N2) flow by addition of N2 at ER of 0.31 to verify the effect of the gasification agent flow rate variation. As the feed flow rate increased from 21 to 31 Nm3/h, the contents of H2, CO, and CO2 in the produced syngas were found to decrease due to the added N2. On the contrary, the content of CH4 increased. The flow rate of the produced syngas increased as N2 was additionally supplied. The flow rate of the syngas produced in the feed flow rate range of 21e28 Nm3/h increased by 10 Nm3/h, which was greater than the flow rate of the additionally supplied N2. Due to the changes of the composition and flow rate of the produced syngas, Xc and CGE showed maximum values of 61.7 and 47.7%, respectively, at the feed flow rate of 28 Nm3/h. In Fig. 6, gasification of CWM-L at a constant ER of 0.44 was Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 5. Effect of feed flow rate on gasification of CWM-H (ER 0.31).
Fig. 6. Effect of feed flow rate on gasification of CWM-L (ER 0.44).
performed to verify the effect of the feed flow rate change at different ER and CWM concentrations. As the feed flow rate increased, the CO content in the produced syngas decreased, and the contents of H2 and CO2 changed slightly. The flow rate of the produced syngas increased with the feed flow rate. The increase of the syngas flow rate in the feed flow rate range of 28e34 Nm3/h was 7.4 Nm3/h, which was greater than that of the flow rate of the additionally supplied N2. However, in the feed flow rate range of 34e37 Nm3/h, the increase of the syngas flow rate was 1.7 Nm3/h, which was smaller than the flow rate of the additionally supplied N2. Due to the variation of the composition and flow rate of the produced syngas, the Xc and CGE showed maximum values of 90.4% and 65.1%, respectively, at the feed flow rate of 34 Nm3/h. The increase of the feed flow rate was found to enhance the CWM atomization and produce smaller droplets [34,35], which increased Xc and CGE [12,36]. However, the increase of the feed flow rate decreased the residence time of the CWM in the gasifier due to the high flow rate. In addition, the inflow of a colder gas in comparison with the gasifier temperature increased, and the injected N2, which does not participate in the reactions but takes thermal energy away from the gasifier, decreased the gasifier temperature [12,26]. The decrease of the CWM residence time and the gasification temperature reduced Xc and CGE. Therefore, the gasification results shown in Figs. 5 and 6 reflect both the positive and negative effects of the increase of the feed flow rate, indicating that an optimum feed flow rate exists depending on the CWM concentration and the ER.
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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Fig. 7. Effect of syngas flow rate on modified diesel engine.
3.5. Application of syngas to dual-fuel diesel engine Fig. 7 shows the results of the application of the syngas produced by CWM-L gasification to a modified dual-fuel diesel engine. While operating the engine under a constant gasification condition of ER 0.44, the syngas was supplied at the constant composition of H2 28.1%, CO 36%, CH4 0.3%, and CO2 35.1%. As shown in Fig. 7, despite the increase of the feed flow rate of the syngas injected into the engine, the BTE at the operation conditions of 26 kW and 40 kW were not significantly change at 24.8% and 34%, respectively. As the syngas feed flow rate increased, the SRR continuously increased due to the syngas replacing diesel, but the BTE remained constant regardless of the increase of the SRR under the constant operation conditions of 26 kW and 40 kW. The BTE was higher in the operation at 40 kW than it was at 26 kW, indicating that the BTE in dual-fuel mode was higher at a higher load [20,28]. In the operation at 26 kW, until the syngas feed flow rate increased to 21 Nm3/h, the SRR was lower than that of the operation at 40 kW, but the highest SRR of 63.3% was found at 26 Nm3/h. A similar result was reported by Sahoo et al. [28], in which the SRR increased with the increase of the engine load, but then decreased after showing a maximum value at a specific load. Thus, an appropriate engine load is required, when a high SRR is required to reduce the diesel consumption and to increase the syngas consumption. As found in Figs. 2e6, the flow rate of the syngas, which affects the SRR, is determined by the gasification conditions including the temperature, CWM concentration and the ER. The composition of the syngas is also determined by the gasification conditions. Hernandez et al. [20] determined the effects that change of contents of H2, CO, and CH4 had on the BTE. Thus, gasification conditions enabling the control of the syngas composition and flow rate should be considered for efficient dual-fuel operation of a diesel engine. Therefore, efficient power generation through entrainedflow gasification requires the optimization of gasification operation, considering not only the gasification efficiency but also the efficiency of the modified dual-fuel diesel engine operation. 4. Conclusion CWMs prepared at different concentrations were gasified through entrained-flow gasifier under various operation conditions. The produced syngas was applied to a modified diesel engine to investigate the power generation from the syngas. As the gasification conditions were varied, the composition of the produced syngas was affected by the Boudouard reaction. The CGE showed a maximum of 66.1% at an ER of 0.43, while Xc was seen to increase with the increase of the ER. The difference in composition of syngas, Xc, and CGE was found for gasification of CWM-H and CWM-L. The gasification of CWM-H showed lower H2/CO ratio, however, higher Xc and CGE than CWM-L. The effect of the feed flow rate was investigated by additionally supplying N2 at a constant ER. In the gasification of CWM-H at the ER of 0.31, Xc Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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and CGE showed maximum values at the gasification agent flow rate of 28 Nm3/h. In the gasification of CWM-L at the ER of 0.44, Xc and CGE showed maximum values of 90.4% and 65.1%, respectively, at the feed flow rate of 34 Nm3/h. The produced syngas was applied to a dual-fuel diesel engine. The BTE remained almost constant despite changes in the flow rate of the syngas injected into the engine. A maximum BTE of 35.1% was found in the operation at 40 kW. The SRR increased with syngas feed flow rate and reached 63.3% at 26 kW. The dual-fuel operation of the diesel engine was found to be dependent on the flow rate of the syngas as well as on the engine load. Thus, entrainedflow gasification operation for power generation requires a determination of the gasification conditions considering both gasification efficiency and diesel engine operation. In the present study, the potential of efficient power generation was verified through a hydrogen-rich syngas production by gasification of CWM and the dual-fuel operation of a diesel engine with syngas. Acknowledgements This research was supported by the Energy Technology Development project of the Ministry of Trade, Industry and Energy in Republic of KOREA (20143030050060). Appendix A. Supplementary data Supplementary data related to this article can be found at https://doi.org/10.1016/j.joei.2018.01.009. References
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mez-Barea, B. Leckner, Modeling of biomass gasification in fluidized bed, Prog. Energy Combust. Sci. (2010), https://doi.org/10.1016/j.pecs.2009.12.002. [1] A. Go [2] K.Y. Koo, H.-S. Roh, U.H. Jung, W.L. Yoon, Combined H2O and CO2 reforming of CH4 over Ce-promoted Ni-Al2O3 catalyst for gas to liquid (GTL) process- enhancement of NieCeO2 interaction, Catal. Today 185 (2012) 126e130, https://doi.org/10.1016/j.cattod.2011.07.027. [3] S.Y. Park, G. Oh, K. Kim, M.W. Seo, H.W. Ra, T.Y. Mun, J.G. Lee, S.J. Yoon, Deactivation characteristics of Ni and Ru catalysts in tar steam reforming, Renew. Energy 105 (2017) 76e83, https://doi.org/10.1016/j.renene.2016.12.045. [4] S. Chen, A. Meng, Y. Long, H. Zhou, Q. Li, Y. Zhang, TGA pyrolysis and gasification of combustible municipal solid waste, J. Energy Inst. 88 (2015) 332e343, https://doi.org/ 10.1016/j.joei.2014.07.007. [5] J.I. Na, S.J. Park, Y.K. Kim, J.G. Lee, J.H. Kim, Characteristics of oxygen-blown gasification for combustible waste in a fixed-bed gasifier, Appl. Energy 75 (2003) 275e285, https://doi.org/10.1016/S0306-2619(03)00041-2. [6] T. Chmielniak, M. Sciazko, Co-gasification of biomass and coal for methanol synthesis, Appl. Energy 74 (2003) 393e403, https://doi.org/10.1016/S0306-2619(02)00184-8. [7] K. Qin, W. Lin, S. Faster, P.A. Jensen, H. Wu, A.D. Jensen, Characterization of residual particulates from biomass entrained flow gasification, Energy and Fuels 27 (2013) 262e270, https://doi.org/10.1021/ef301432q. [8] A.D. Lewis, T.M. Holland, N.R. Marchant, E.G. Fletcher, D.J. Henley, E.G. Fuller, T.H. Fletcher, Steam gasification rates of three bituminous coal chars in an entrained-flow reactor at pressurized conditions, Energy and Fuels 29 (2015) 1479e1493, https://doi.org/10.1021/ef502608y. [9] A.H. Tchapda, S.V. Pisupati, Characterization of an entrained flow reactor for pyrolysis of coal and biomass at higher temperatures, Fuel 156 (2015) 254e266, https:// doi.org/10.1016/j.fuel.2015.04.015. [10] J. Billaud, S. Valin, M. Peyrot, S. Salvador, Influence of H2O, CO2 and O2 addition on biomass gasification in entrained flow reactor conditions: experiments and modelling, Fuel 166 (2016) 166e178, https://doi.org/10.1016/j.fuel.2015.10.046. [11] S. Chaiklangmuang, K. Kurosawa, L. Li, K. Morishita, T. Takarada, Thermal degradation behavior of coffee residue in comparison with biomasses and its product yields from gasification, J. Energy Inst. 88 (2015) 323e331, https://doi.org/10.1016/j.joei.2014.08.001. [12] S.J. Yoon, Y.C. Choi, Y. Il Son, S.H. Lee, J.G. Lee, Gasification of biodiesel by-product with air or oxygen to make syngas, Bioresour. Technol. 101 (2010) 1227e1232, https:// doi.org/10.1016/j.biortech.2009.09.039. [13] S.H. Lee, S.J. Yoon, H.W. Ra, Y. Il Son, J.C. Hong, J.G. Lee, Gasification characteristics of coke and mixture with coal in an entrained-flow gasifier, Energy 35 (2010) 3239e3244, https://doi.org/10.1016/j.energy.2010.04.007. [14] P. Feng, W. Lin, P.A. Jensen, W. Song, L. Hao, K. Raffelt, K. Dam-Johansen, Entrained flow gasification of coal/bio-oil slurries, Energy 111 (2016) 793e802, https://doi.org/ 10.1016/j.energy.2016.05.115. [15] I. Adeyemi, I. Janajreh, Modeling of the entrained flow gasification: kinetics-based ASPEN Plus model, Renew. Energy 82 (2015) 77e84, https://doi.org/10.1016/ j.renene.2014.10.073. [16] M. Saiful Alam, A.T. Wijayanta, K. Nakaso, J. Fukai, Study on coal gasification with soot formation in two-stage entrained-flow gasifier, Int. J. Energy Environ. Eng. 6 (2015) 255e265, https://doi.org/10.1007/s40095-015-0173-1. [17] M.B. Tilghman, R.E. Mitchell, Impact of Co-firing coal and biomass on mixed char reactivity under gasification conditions, Energy and Fuels 30 (2016) 1708e1719, https:// doi.org/10.1021/acs.energyfuels.5b02480. [18] S. Xu, Y. Ren, B. Wang, Y. Xu, L. Chen, X. Wang, T. Xiao, Development of a novel 2-stage entrained flow coal dry powder gasifier, Appl. Energy 113 (2014) 318e323, https:// doi.org/10.1016/j.apenergy.2013.07.045. [19] J. Tanner, S. Bhattacharya, Kinetics of CO2 and steam gasification of Victorian brown coal chars, Chem. Eng. J. 285 (2016) 331e340, https://doi.org/10.1016/ j.cej.2015.09.106. ndez, M. Lapuerta, J. Barba, Separate effect of H2, CH4 and CO on diesel engine performance and emissions under partial diesel fuel replacement, Fuel 165 (2016) [20] J.J. Herna 173e184, https://doi.org/10.1016/j.fuel.2015.10.054. ndez, M. Lapuerta, J. Barba, Effect of partial replacement of diesel or biodiesel with gas from biomass gasification in a diesel engine, Energy 89 (2015) 148e157, [21] J.J. Herna https://doi.org/10.1016/j.energy.2015.07.050. [22] A.L. Boehman, O. Le Corre, Combustion of syngas in internal combustion engines, Combust. Sci. Technol. 180 (2008) 1193e1206, https://doi.org/10.1080/ 00102200801963417. [23] G. Diaz, V.A. Kuznetsov, I.I. Kumkova, A.N. Bratsev, I.I. Kumkova, Experimental Study on the Effect of Varying Syngas Composition on the Emissions of Dual Fuel CI Engine Operating at Various Engine Speeds, IOP Conf. Series: Mater. Sci. Eng. 100, 2015, https://doi.org/10.1088/1757-899X/100/1/012006, 012006. [24] F. Christodoulou, A. Megaritis, The effect of reformer gas mixture on the performance and emissions of an HSDI diesel engine, Int. J. Hydrogen Energy 39 (2014) 9798e9808, https://doi.org/10.1016/j.ijhydene.2014.03.090. [25] Y.C. Choi, X.Y. Li, T.J. Park, J.H. Kim, J.G. Lee, Numerical study on the coal gasification characteristics in an entrained flow coal gasifier, Fuel 80 (2001) 2193e2201, https:// doi.org/10.1016/S0016-2361(01)00101-6. [26] S.J. Yoon, Y.M. Yun, M.W. Seo, Y.K. Kim, H.W. Ra, J.G. Lee, Hydrogen and syngas production from glycerol through microwave plasma gasification, Int. J. Hydrogen Energy 38 (2013) 14559e14567, https://doi.org/10.1016/j.ijhydene.2013.09.001. [27] N. Kobayashi, M. Tanaka, G. Piao, J. Kobayashi, S. Hatano, Y. Itaya, S. Mori, High temperature air-blown woody biomass gasification model for the estimation of an entrained down-flow gasifier, Waste Manag. 29 (2009) 245e251, https://doi.org/10.1016/j.wasman.2008.04.014. [28] B.B. Sahoo, N. Sahoo, U.K. Saha, Effect of H2:CO ratio in syngas on the performance of a dual fuel diesel engine operation, Appl. Therm. Eng. 49 (2012) 139e146, https:// doi.org/10.1016/j.applthermaleng.2011.08.021. [29] S. Sugiyama, N. Suzuki, Y. Kato, K. Yoshikawa, A. Omino, T. Ishii, K. Yoshikawa, T. Kiga, Gasification performance of coals using high temperature air, Energy 30 (2005) 399e413, https://doi.org/10.1016/j.energy.2004.06.001. [30] F. Guo, Y. Dong, L. Dong, C. Guo, Effect of design and operating parameters on the gasification process of biomass in a downdraft fixed bed: an experimental study, Int. J. Hydrogen Energy 39 (2014) 5625e5633, https://doi.org/10.1016/j.ijhydene.2014.01.130.
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009
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[31] G. Oh, S.Y. Park, M.W. Seo, Y.K. Kim, H.W. Ra, J.G. Lee, S.J. Yoon, Ni/Ru-Mn/Al2O3 catalysts for steam reforming of toluene as model biomass tar, Renew. Energy 86 (2016) 841e847, https://doi.org/10.1016/j.renene.2015.09.013. [32] G.A. Olah, A. Goeppert, M. Czaun, T. Mathew, R.B. May, G.K.S. Prakash, Single step Bi-reforming and oxidative Bi-reforming of methane (natural gas) with steam and carbon dioxide to metgas (CO-2H2) for methanol synthesis: self-sufficient effective and exclusive oxygenation of methane to methanol with oxygen, J. Am. Chem. Soc. 137 (2015) 8720e8729, https://doi.org/10.1021/jacs.5b02029. rez-Uriarte, M. Sa nchez-Contador, J. Eren ~ a, A.T. Aguayo, J. Bilbao, Direct synthesis of dimethyl ether from syngas on CuOZnOMnO/SAPO-18 bifunctional [33] A. Ateka, P. Pe catalyst, Int. J. Hydrogen Energy 41 (2016) 18015e18026, https://doi.org/10.1016/j.ijhydene.2016.07.195. [34] Y. Hai-long, Z. Chao, L. Jian-zhong, C. Ke-fa, Experimental study of the atomizing performance of a new type of nozzle for coal water slurry, Energy and Fuels 22 (2008) 1170e1173, https://doi.org/10.1021/ef700553s. [35] Z. Yan, Q. Liang, Q. Guo, G. Yu, Z. Yu, Experimental investigations on temperature distributions of flame sections in a bench-scale opposed multi-burner gasifier, Appl. Energy 86 (2009) 1359e1364, https://doi.org/10.1016/j.apenergy.2008.09.020. [36] T. Jakobs, N. Djordjevic, S. Fleck, M. Mancini, R. Weber, T. Kolb, Gasification of high viscous slurry R&D on atomization and numerical simulation, Appl. Energy 93 (2012) 449e456, https://doi.org/10.1016/j.apenergy.2011.12.026.
Please cite this article in press as: G. Oh, et al., Syngas production through gasification of coal water mixture and power generation on dual-fuel diesel engine, Journal of the Energy Institute (2018), https://doi.org/10.1016/j.joei.2018.01.009