IMPACT OF PETROLEUM BASED RESIDUES TREATMENT METHODS PRIOR TO BURNING IN THE SHIP BOILERS ON THE CO, CO2, AND NOX EMISSION LEVEL

Author(s):  
Marcin Skarbek_Zabkin
2014 ◽  
Vol 115 ◽  
pp. 360-373 ◽  
Author(s):  
Maryori Díaz-Ramírez ◽  
Fernando Sebastián ◽  
Javier Royo ◽  
Adeline Rezeau

Author(s):  
Satoru Goto ◽  
Sadao Nakayama ◽  
Yoshiharu Ono ◽  
Yoshifumi Nishi

Abstract Lean-burn gas engines are operating worldwide because of having an advantage of lower NOx emission and higher thermal efficiency than those of stoichiometric gas engines. The modern lean-burn gas engines, especially medium and large size, have the pre-combustion chamber technology. On the contrary, there are some problems that originate in the spark plug. Particularly near the ignition plug located in the center, the fuel gas density is lean, affected by the lean-gas mixture coming from the main combustion chamber during the compression stroke and the fuel gas density near the wall is rich. The lifetime of ignition plug is likely to be shorter than those used in the conventional theoretical mixture gas combustion engine, because the required voltage for the plug is high, which reaches 20–25 kV or more. The authors and their colleagues have studied a combustion method of using micro-pilot fuel oil instead of spark plug as an ignition source in recent four years to provide a solution for the above mentioned technical problems. The energy of micro-pilot fuel oil is equivalent to 1% of the total thermal input, but the energy of the pilot fuel oil is several thousands times of the spark ignition. According to the author’s study, NOx emission level is defined by the amount of pilot fuel oil. But only about 1% fuel can meet the NOx target. NOx emission level meets TA-Luft of 500 mg/m3N @ 5% O2. Even the regulation of 200 ppm @ 0% O2 in the Japanese large cities can be achieved, this level is almost corresponding to the half TA-Luft. This paper describes the performance being desired for gas engines through the service-experience in co-generation fields and also describes the newly developed gas engine corresponding to a 1000 kW class, which has micro-pilot fuel oil ignition method. This engine has the same performance of a diesel engine, BMEP of 2.3 MPa and brake thermal efficiency of 43%.


2021 ◽  
Vol 12 (2) ◽  
pp. 16-35
Author(s):  
Suman Kumar Dey ◽  
Deba Prasad Dash ◽  
Mousumi Basu

This article presents a multi-objective economic environmental/emission dispatch (EED) of variable head hydro-wind-thermal power system. The combination of NOx emission, SO2 emission, and fuel cost are minimized for non-smooth hydrothermal plants while satisfying various operational constraints like non-smooth fuel cost, penalty coefficient, and wind power uncertainty. The objectives—cost, NOx emission, and SO2 emission—are optimized at the same time. In this research, the non-dominated sorting genetic algorithm-II (NSGA-II) has been employed for solving the given problem where the total cost, NOx emission level, and SO2 emission level are optimized at the same time while satisfying all the operational constraints. The simulation results that are obtained by applying the two test systems on the proposed scheme have been evaluated against strength pareto evolutionary algorithm 2 (SPEA 2).


Author(s):  
V. V. Tsatiashvili ◽  
V. G. Avgustinovich

Reduction of NOx emission of aircraft gas turbines is moving in the direction of development of direct combustor fuel injection systems providing conditions for rapid mixing and combustion of a uniform lean fuel/air mixture. However, formation of sufficient uniform fuel/air mixture in real combustors fails to be completed. It may result in burning out a considerable portion of fuel in stoichiometric conditions that in turn imposes limits on the emission level minimizing. The research accomplished by a number of authors justifies the necessity of decreasing the extent of stoichiometric zones by means of increasing fuel-air mixing rate on the stoichiometric surface of their contact, to reduce emission. This publication contains the analysis results upon the effect of mixing rate, in terms of a methane-air laminar diffusion combustion. It is proved that changes of mixing rate influence the two main factors governing the emission level: the extent of NO production zone and the efficient rate of its production. If the mixing rate increases explicitly due to the decrease of NOx production scale, the efficient velocity curve will contain a maximum value. Furthermore, the scale effect is all-over stronger than the kinetic one. It is concluded that in case of mixing rate increase, the reduction of NOx emission goes nonlinearly and steadily. The ranges of maximum effect are specified. Herewith, we introduce the relation, which demonstrates that in the diffusion combustion a sufficient reduction of NOx emission can be achieved.


Author(s):  
A. N. Dubovitsky ◽  
◽  
E. D. Sverdlov ◽  
K. S. Pyankov ◽  
H. F. Valiev ◽  
...  

To reduce the NOx emission level in low emission combustors designed for industrial gas turbines, the technology of lean preliminary mixed fuel-air mixtures burning is used. But this gives rise to combustion instability modes.


Author(s):  
Jianwen Xie ◽  
Weidong Fan ◽  
Jianwen Zhang

A 600MW tangentially fired sub-critical boiler with the volume heat load of 87.6kW/m3 at the case of BMCR was not originally equipped with the separated over fire air (SOFA) system. Shenhua bituminous coal with low ash fusion point and strong slagging characteristics is employed as its design coal. To prevent serious slagging on its platen heaters, it is necessary to employ 80% Shenhua bituminous coal with low ash fusion temperature blending 20% Shenhua bituminous coal with high ash fusion temperature. However, NOx emission value at the furnace exit reaches more than 370mg/m3 (O2 = 6%). In order to achieve a NOx emission limitation level below 100mg/m3 (O2 = 6%) for pulverized coal power boilers which meets the requirement from latest Chinese environmental protection regulation, while considering a low cost of retrofit, a comprehensive low NOx emission boiler retrofit scheme combining air-staged low NOx combustion technology and selective catalytic reduction of flue gas in the low temperature flue duct of boiler was selected preferentially. Two-level air staging technology has some obvious advantages including a little negative effect on the boiler’s combustion efficiency, and easily achieving deep air-staged combustion mode. Therefore, a study of numerical simulation concerning original combustion mode and optimized two-level air staging combustion mode was conducted. Due to excellent ignition and burnout characteristics of Shenhua bituminous coal with high volatile matter, low ash fusion temperature and reasonable configuration of upper and lower burnout air ports, the NOx emission level at the exit of furnace would be greatly reduced, and the fouling layer temperature of water wall obviously decreases, which means a definite improvement of clean degree of furnace. And the gas temperature at the bottom of platen heaters decreases about 20 °C while burning 100% Shenhua bituminous coal with low ash fusion temperature. However, its combustion efficiency would decline weakly. The performance of boiler was optimized by combustion tests after the retrofit. This boiler can fully burn Shenhua bituminous coal with low ash fusion temperature by use of two-level air staging system, and furnace soot blowing frequency also lowered. Consequently, exhaust gas temperature decreased, which achieved an increase of boiler efficiency by about 0.3%. In addition, NOx emission level decreased more than 60%, and was about 15 mg/m3 (O2 = 6%) lower than coal blending cases. To meet a full burning of Shenhua bituminous coal with low ash fusion temperature, it is suggested that two-level air staging technology should be applied to the retrofit of boiler. And then goals of low NOx emission and anti-slagging on the platen heaters can be achieved.


2013 ◽  
Vol 724-725 ◽  
pp. 1422-1426
Author(s):  
Jian Xi Pang ◽  
Da Wei Qu ◽  
Xiao Lu ◽  
Guang Yang Liu

Experimental research on the effect of excess air ratio on dynamic and emission performance of turbocharged lean-burned CNG engine. The 12 test conditions contain engine speeds of 1300r/min, 1600r/min, and 1900r/min, with 25%, 50%, 75%, 100% load separately. When keeping other combustion boundary conditions unchanged, the excess air ratio has little effect on engine output torque at almost all test conditions, but has obvious effect on CH4 and NOx emission. With the excess air ratio increasing, the emission of CH4 has increased while the NOx emission has decreased significantly. When the λ value is in the range of 1.4-1.45, the emission level is lower.


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