The newly issued gb31570-2015 "emission standard for pollutants in petroleum refining industry" requires that the emission limit of NOx≤150mg/ nm3@3.5%o2 in the process heating furnace of existing petroleum refining and chemical enterprises (hereinafter referred to as refining and chemical enterprises) shall be implemented from July 1, 2017.
In existing refinery process using the traditional heating furnace burner is still cannot achieve NOx emissions of 150 mg/Nm3@3.5 % or less O2, emissions of waste gas heating furnace mainly comes from the flammable gas in the burner combustion to produce nitrogen oxides, combustible gas is produced by burning spray gun to regularly after ever-burning lamps light burning chamber, therefore, combustible gas can achieve full combustion is precondition to determine whether emissions standards, and the atmosphere of the combustible gas can fully burning and the combustion chamber and the flow field is closely related to the conventional combustion gun only one nozzle, the flow field of the combustion chamber is very difficult to form stable.Therefore, it is necessary to improve the fuel gun structure of burner.
Technical implementation elements:
In view of this, the company provides a center-ignition low-nitrogen emission fuel gun for the burner of the process heating furnace. The fuel gun can meet the requirements of low-nitrogen transformation of the burner of the process heating furnace of the refinery enterprise. After operation, the burner can meet the emission requirements of NOx≤150mg/ nm3@3.5%o2.The fuel gun comprises a long light and a group of guns which are distributed in a circumferential direction around the center of the long light;Gun is the top of the cavity structure of the ball head, ball head spray has three holes, three spray hole distribution on a ball head points on a curve, in the middle of the nozzle at the top of the ball head after the fuel spray from the middle hole jet direction are consistent with the center of the gun axis, fuel from the remaining two are tilted divergent nozzle jet, a jet direction toward the pilot burner, another jet direction ever-burning lamps to deviate from the direction.
Further, the included Angle between the central axis of the middle nozzle and the central axis of the gun is 4 ~ 6°, the included Angle between the central axis of the nozzle facing the lamp and the central axis of the gun is 12 ~ 18°, and the included Angle between the central axis of the nozzle deviating from the direction of the lamp and the central axis of the gun is 22 ~ 28°.The gun and lamp are mounted and fixed together through the base.
Beneficial effects: the fuel gun ever-burning lamps will be set in the center of the positive, gun using took, vertical upward and outward direction of three kinds of injection form three reaction zone, in the area of the combustion reaction of fuel match each other, can not only guarantee the stability of combustion, and can guarantee a certain proportion of flue gas flow, fuel combustion can fully and completely, combustion products of nitrogen oxides significantly decreased relative to the conventional combustion gun, promote the burner of nox emission reduction.
Fuel is ejected from the remaining two jets in a slanted and divergent direction, one toward the lamp and the other away from the lamp.Jet axis direction toward the ever-burning lamps of the center of the nozzle and the center of the gun axis Angle is 15 ° and fuel from the nozzle jet after have the effect of stable flame, jet direction deviating from the direction of the pilot burner nozzle hole at the center of the axis and the Angle of the center of a gun is 25 °, after the fuel from the nozzle jet fuel for grading.
Working principle: the reaction zone formed by the jet orienting toward the nozzle of the lamp plays the role of flame stabilization: the proportion of primary fuel in the total fuel is small, and the jet momentum is low. After the low-momentum primary fuel converges into the center, local stagnation reflux area will be generated, and these stagnation reflux areas play the role of flame stabilization.
The reaction zone formed by the jet hole deviating from the direction of the long lamp plays the role of fuel classification: secondary fuel accounts for about 30% of the total fuel, and 30% of the secondary fuel and air reaction will form the low-temperature condition of lean fuel, which will inhibit NOx formation at low temperature.On the other hand, 30% of the secondary fuel and air reaction will form oxygen-poor flue gas, which enters the downstream and becomes an oxidant in the backflow area of flue gas. This oxidant has a certain temperature and can directly ignite the fuel for three times.Formed in the middle of the nozzle plays a role of flue gas of reflux reaction zone: three fuel accounts for more than half of the total fuel, jet momentum, high injection speed, high speed of three times the fuel jet induced by high temperature flue gas back into the three times of the reaction zone, and promote the backflow of flue gas and fuel, three times the secondary reaction zone oxygen-depleted gas fast mixing, reflux flue gas mixture will be diluted reactants to hypoxic reaction conditions, low oxygen inhibition of NOx formation.
To sum up, the above are only better examples, not the protection scope.
