A kind of catalytic cracked regenerated process denitrating techniqueTechnical field
The present invention relates to a kind of denitrating technique, be specifically related to a kind of technique of catalytic cracked regenerated process denitration, belong to technical field of petrochemical industry.
Background technology
Along with the increasingly stringent of environmental regulation, the requirement of country to the restriction of oil refining enterprise's Air Pollutant Emission is also stricter.The emission limit of current country to most area existing enterprise nitrogen oxide is 240mg/m3, July 1 in 2014, the emission limit of Qi existing enterprise nitrogen oxide reduced to 100mg/m3, and some area is even lower.Reaching this standard, there is certain difficulty in existing exhaust gas denitration technology.Exhaust gas denitration technology conventional both at home and abroad has dry method exhaust gas denitration and wet method exhaust gas denitration.The dry method exhaust gas denitration technology that present commercial plant adopts mainly comprises selective catalytic reduction (SCR) and SNCR method (SNSR), but these two kinds of technology also exist the shortcomings such as cost of investment is high, denitration rate is low.And wet method exhaust gas denitration technology industrially Application comparison many have sour absorption process, aqueous slkali absorption process, oxidative absorption method, liquid-phase reduction absorption process etc., wet method exhaust gas denitration technology has the advantages such as process equipment is relatively simple, operating temperature is lower, energy consumption is low, disposal cost is lower, has research and industrial application value.
Urea wet method exhaust gas denitration technology belongs to liquid-phase reduction absorption process, the waste liquid absorbed uses through supplementing fresh urea Posterior circle, do not produce discarded absorbing liquid, the problems such as the side reaction that the technology such as traditional WATER-WASHING METHOD, aqueous slkali absorption process, selective catalysis ammonia reducing process that avoids exists is many, the difficult recovery of byproduct and acid pollution, can reach the requirement of environmental protection.Therefore be widely used in the exhaust-gas treatment that urea wet denitration is high in NOx concentration, fluctuation range is large.The NOx waste gas that this research produces for desulfuration adsorbent process units, adopts urea/O3wet method exhaust gas denitration technique carries out pilot plant test, investigates exhaust gas flow and O3flow is on the impact of NOx removal effect in waste gas, and O3oxidation progression on the impact of NO removal effect and NOx removal efficiency, and contrasts with the hypergravity applied/absorption tower urea wet method exhaust gas denitration technology, provides theoretical foundation for meeting higher environmental requirement after desulfuration adsorbent process units exhaust gas denitration.
In the waste gas that desulfuration adsorbent process units produces, NOx is mainly NO and NO2, wherein NO2generation HNO soluble in water3and HNO2, urea liquid is a kind of strong reducing agent, is easy to nitric acid, nitrous acid to be reduced to nitrogen under sour environment, and NO compares NO2more difficult absorption.Therefore this test adopts O3first NO is oxidized to NO2, NO2water-solublely to react with urea liquid further afterwards, thus improve denitration rate, concrete reaction is:
201310279499.X discloses a kind of SNCR denitration device and utilizes this device to carry out the method for denitration, described device comprises Benitration reactor (1), fuel injection control system (2), temperature control equipment (3), injection of reducing agent injection device (4), Benitration reactor exhaust pass (5), Benitration reactor inlet flue duct (6), fuel system controller (8), described fuel injection control system (2), temperature control equipment (3), injection of reducing agent injection device (4), Benitration reactor exhaust pass (5), Benitration reactor inlet flue duct (6) is installed in (1) on Benitration reactor, described fuel injection control system (2) is connected with described temperature control equipment (3) by described fuel system controller (9).Method of denitration provided by the invention utilizes denitrification apparatus of the present invention to carry out.Unit efficiency of the present invention is high, small investment, recuperation of heat are profitable.
201510309481.9 disclose a kind of denitrification apparatus, liquefied ammonia evaporator, blending tank, Benitration reactor, blower fan, liquefied ammonia evaporator is connected with ammonia excretion tank, ammonia excretion tank is connected with purification tank for liquid waste, arranges ammonia-spraying grid in the connection flue of blending tank and Benitration reactor, the spray ammonia arm that ammonia-spraying grid includes spray ammonia house steward and is assemblied on flue body, spray ammonia arm is connected by tube connector with described spray ammonia house steward, spray ammonia arm is evenly distributed with ammonia nozzle, tube connector is respectively arranged with control valve, the two ends cross-over connection of control valve has differential manometer, each control valve is connected, it flashes to ammonia by liquefied ammonia in liquefied ammonia evaporator, and send into ammonia-spraying grid after mixing in blending tank with the air introduced by blower fan, flue is sprayed into by ammonia-spraying grid, the pressure differential that the aperture of the control valve in ammonia-spraying grid records according to differential manometer regulates, Benitration reactor reaction is entered after ammonia fully mixes with nitrogen oxide, its structure is simple, and denitration efficiency is high.
Summary of the invention
The object of this invention is to provide a kind of catalytic cracked regenerated process denitrating technique, this technology can realize removing the NOx that desulfuration adsorbent process units produces.
A kind of catalytic cracked regenerated process denitrating technique, comprises the steps:
(1) waste gas is by blower fan suction one-level positive displacement oxidator, drives ozone generator, opens ozone pipeline valve, logical O3;
(2) waste gas and O3stair oxidation reaction is carried out in positive displacement oxidator 1;
(3) Urea Absorbing Tower 1 is entered, the NOx of absorption portion after oxidation;
(4) remainder of exhaust gas enters after secondary oxidation occurs positive displacement oxidator 2, enters Urea Absorbing Tower 2;
(5) giving vent to anger of Urea Absorbing Tower 2 enters positive displacement oxidator 3, enters Urea Absorbing Tower 3 after there is tertiary oxidation;
(6) waste gas is emptying after three grades of tower process;
(7) urea absorption liquid is by pump from each Urea Absorbing Tower of urea cycle groove suction, thus recycles;
(8) after system stability, the mass concentration of NOx in device import and export flue gas is detected.
Waste gas described in step (1) is the NOx that desulfuration adsorbent process units produces.
Positive displacement oxidator specification described in step (2) is φ 300x500mm.
Urea Absorbing Tower described in step (3) is self-control stainless steel helices tower, and specification is φ 300x1400mm.
Positive displacement oxidator specification described in step (4) is φ 300x500mm
Urea Absorbing Tower described in step (4) is self-control stainless steel helices tower, and specification is φ 300x1400mm.
Positive displacement oxidator specification described in step (5) is φ 300x500mm.
Urea Absorbing Tower described in step (5) is self-control stainless steel helices tower, and specification is φ 300x1400mm.
Tool of the present invention has the following advantages:
(1) waste liquid that the method absorbs uses through supplementing fresh urea Posterior circle, does not produce discarded absorbing liquid, there is not side reaction many and byproduct difficulty and reclaims and the problem such as acid pollution, environmentally safe;
(2) process equipment is relatively simple, operating temperature is lower, energy consumption is low, disposal cost is lower.
Detailed description of the invention
Be described in further details the present invention below by embodiment, these embodiments are only used for the present invention is described, do not limit the scope of the invention.
Embodiment
A kind of catalytic cracked regenerated process denitrating technique, the flue gas in process of the test is the NOx waste gas that desulfuration adsorbent process units produces, and in order to by fully oxidized for the NO in waste gas, and fully reacts with urea absorption liquid, devises O3generating means and cyclic absorption device.O3the O that generating means produces3enter one-level, secondary and three grades of positive displacement oxidators respectively, in positive displacement oxidator, NO is oxidized to NO2.Cyclic absorption device is Urea Absorbing Tower and circulating slot.Positive displacement oxidator specification is φ 300x500mm; Urea Absorbing Tower is self-control stainless steel helices tower, and specification is φ 300x1400mm.In order to increase gas liquid interfacial area, in absorption tower, load a certain amount of φ 6mm type ceramic raschig rings.Waste gas, by blower fan suction one-level positive displacement oxidator, is driven ozone generator, is opened ozone pipeline valve, logical O3waste gas and O3in positive displacement oxidator 1, carry out stair oxidation reaction, after oxidation, enter Urea Absorbing Tower 1, the NOx of absorption portion; Remainder of exhaust gas enters after secondary oxidation occurs positive displacement oxidator 2, and enter Urea Absorbing Tower 2, most of NOx is by being absorbed with urea reaction; Giving vent to anger of Urea Absorbing Tower 2 enters positive displacement oxidator 3, and enter Urea Absorbing Tower 3 after there is tertiary oxidation, waste gas is emptying after three grades of tower process.Urea absorption liquid, thus to be recycled from each Urea Absorbing Tower of urea cycle groove suction by pump.After system stability, the mass concentration of NOx in device import and export flue gas is detected.