A kind of improved plasma ignition nozzle of coal dust gasifier
Technical field
The utility model belongs to coal gasification apparatus igniting field, refers in particular to the plasma ignition mode of the gasification furnace of fine coal charging, is the improvement to existing powder coal gasification furnace sparking mode.
Background technology
At present, powder coal gasification furnace mainly contains the two stage gasifier of Shell gasification furnace, Prenflo gasification furnace, Xi'an thermal technology institute etc., and the common feature of its driving ignition process is that sparking mode is too loaded down with trivial details, and nozzle arrangements and logic control are very complicated.Such gasification furnace has disposed three class nozzles according to different purposes: ignition burner (1), the nozzle that goes into operation (1) and coal nozzle (4-8).Its sequencing that uses in gasification furnace feeds intake driving is: the ignition burner → nozzle that goes into operation → coal nozzle.Promptly properly mixed instrument air and liquefied petroleum gas are lighted, then relied on the stable burning things which may cause a fire disaster of ignition burner to add that the appropriate oxygen oil ratio of the nozzle that the goes into operation nozzle that will go into operation lights by the electricity sparking of ignition burner igniter.After the nozzle that goes into operation is lighted, gasification furnace boosts gradually, pressure drops into the 1st coal nozzle during near 1.0MPa (at pressure during near 0.65MPa, start the Quench air compressor and adjust stable), after the 1st coal nozzle successfully lighted, stablize a few minutes, drop into the 2nd coal nozzle again, 4 coal nozzles drop into the most at last, the gasification furnace initial success that feeds intake.The shortcoming of this ignition process is:
1, in whole gasification furnace feeds intake driving, ignition burner is easy to light, the nozzle that goes into operation is lighted a fire and successfully but had certain difficulty, and is easy to go wrong in the ignition process of nozzle that goes into operation: the igniting shortage of heat especially is difficult for lighting to the low fire coal of fugitive constituent value; The nozzle head that goes into operation often burns out, and produces and uses and the maintenance cost height; Service life of equipment is short, and fuel combustion is insufficient, and fuel heat utilization is low; The start-up course complexity starts and the blowing out inconvenience.
2, to install independently fuel supply and storage system.The price of common fuel oil and combustion gas is than used solid fuel height, and fuel oil, combustion gas that igniting need be a large amount of, and the continuous rise along with oil product and combustion gas price has increased factory's operating cost.
3, because igniting is unfavorable, thereby cause subsequent combustion incomplete, produce to the waste of the energy with to the pollution of environment.Unburnt fine coal particle produces adherent slagging scorification phenomenon near the internal face port and the port, thereby causes the generation of high temperature corrosion, has greatly influenced the service life of nozzle.
In the prior art, existing relevant patent is transformed ignition burner, such as, the patent No. is 200820152717.8, name is called the patent of " a kind of powder coal gasification furnace composite startup nozzle "; The patent No. is 200820020573.0, and name is called the patent of " combined type coal gasification burner ".Though these patents are transformed nozzle, but still adopt natural gas and fuel oil to light a fire, fundamentally do not eliminate the drawback that the tradition igniting exists.
Plasma ignition and stable combustion technology are the new technologies of replace oil with coal in a pulverized coal boiler igniting and the steady combustion process, in the coal-burning power plant, have successfully realized not needing to drop into oil gun before black furnace starts, and can realize the function of plasma direct-fire.In the plasma ignition start-up course, the plasma ignition nozzle is overtemperature not, and the boiler heating curve satisfy to start requirement fully, successful is applied to many station boilers.Easy to control and the energy smooth combustion of plasma torch, characteristic according to its smooth combustion, can control flexibly by the speed of regulating fuel supplying, therefore, plasma apparatus is suitable for the igniting as all solids gasifier fuel, needn't add fuel such as using fuel oil or combustion gas, it is dangerous minimum that fire extinguishing and generation are exploded.
In the structure of prior art ionic medium generating apparatus as shown in Figure 1, plasma generator 3 comprises anode 31, negative electrode 32 and coil 33.Wherein negative electrode 32 and anode 31 are made by high conductivity, high thermal conductivity and oxidation resistant special material, impact to bear high-temperature electric arc.Coil 33 has anti-high direct voltage breakdown capability under high-temperature condition.Its ignition principle is: under certain output current condition, after negative electrode advanced with the anode contact, system was in short-circuit condition, when negative electrode slowly leaves anode, produced electric arcs 35 in the discharge cavity 34, and electric arc 35 is drawn out the jet pipe outside under the effect of coil magnetic field.Under the effect of compressed air at electric arc that enters in compressed air inlet 36, be ionized and be high-temperature plasma 37, plasma contains a large amount of chemically-active particles, as atom (C, H, O), ion (O
2-, H
+, OH
-) and electronics etc.This plasma forms the great localized hyperthermia of the gradient fire nuclear of T>5000K in ignition burner, pulverized coal particle discharges volatile matter rapidly during by this plasma " fire nuclear ", and makes the pulverized coal particle pulverizing of breaking, thereby burning rapidly, reaching a little fights quickens the purpose of pulverized coal friring.For protection plasma generator device itself, need with water cooling cathode and anode and coil, plasma generator is provided with cooling water intake 38 and coolant outlet 39.
How adopting plasma technology to solve the problems of the technologies described above, then is the design problem of utility model.
The utility model content
In view of this, the utility model provides a kind of powder coal gasification furnace sparking mode, a kind of powder coal gasification furnace plasma ignition mode especially is provided, replace existing ignition burner and the nozzle that goes into operation, do not need fuel oil and combustion gas, directly the coal nozzle is lighted, realized on the function " two-in-one ", thereby reach igniting heat abundance, ignition is easy, fuel combustion is abundant, energy savings, be beneficial to environmental protection, adapt to the purpose that coal-fired ability is strong, prolong service life of equipment, reduction use cost.
For reaching above-mentioned purpose, the utility model adopts following technical scheme:
A kind of improved plasma ignition nozzle of coal dust gasifier, be connected with plasma generator, comprise outer sleeve, outwards be disposed with central tube one-level combustion chamber and inner sleeve secondary combustion chamber from the outer sleeve center, inner sleeve secondary combustion chamber space is greater than central tube one-level combustion chamber, central tube one-level combustion chamber connects fine coal and air intake, and inner sleeve secondary combustion chamber connects oxygen intake.
The advantage of utility model is:
1, the utility model is used Plasma Firing Technology, to the original nozzle transformation that goes into operation of powder coal gasification furnace, directly lights a fire with fine coal.Because this sparking mode is convenient to install, effect stability is reliable, can extensively use in the gasification furnace of various fine coal chargings, and simple in structure, cost is low, handling safety.
2,, thereby obtained the beneficial effect being convenient to implement because the plasma ignition generator described in the utility model device general for market purchases.
3, the plasma ignition nozzle can be installed on the new gasification furnace, also can be used for replacing the existing gasification furnace igniting and the nozzle that goes into operation, and gasification furnace structure needn't be done bigger change.
4, adopt Plasma Firing Technology to save fuel oil and combustion gas cost, have good economic benefit, the environmental pollution that over-emitting black exhaust causes when having overcome fuel ignition has simultaneously improved environmental benefit.
5, because the plasma ignition nozzle uses solid fuel, avoid using the storage and the supply equipment of fuel oil or combustion gas, thereby make the bunkering management convenient.
6, after satisfying gasification furnace igniting requirement, the plasma ignition nozzle can utilize automatic extending-contracting apparatus to withdraw from.
Description of drawings
Fig. 1 is existing plasma generator apparatus structure schematic diagram;
Fig. 2 is the improved plasma ignition nozzle arrangements of a utility model schematic diagram;
Fig. 3 is the overall structure schematic diagram of the improved powder coal gasification furnace plasma ignition of the utility model mode.
The specific embodiment
For making your auditor know composition of the present utility model, and embodiment, cooperate graphic being described as follows now:
Under low fire box temperature, can't light by entrainmenting the interior hot flue gas heating of stove because of containing the powder jet, must be by self flame propagation effect, impel the jet complete inflammation, therefore in order to utilize Plasma Firing Technology, need the original nozzle transformation that goes into operation of gasification furnace, improved plasma ignition nozzle arrangements as shown in Figure 2, characteristics are: identical with the geometry overall dimensions of the original nozzle that goes into operation of gasification furnace; Keep close with the moment of momentum of original jet expansion air-flow that goes into operation; And use multistage amplification principle, plasma ignition device partly is made up of plasma generator 3, plasma ignition nozzle 2, outer sleeve 5, inner sleeve secondary combustion chamber 6, central tube one-level combustion chamber 7 etc.
Central tube one-level combustion chamber 7: introduce the pulverized coal borne air flow (coal dust and air 1) after concentrating, strong electrochemical reaction takes place at this in plasma-arc and coal dust, and the coal dust cracking produces a large amount of fugitive constituents and lighted generation one-level flame;
Inner sleeve secondary combustion chamber 6: fugitive constituent and coal dust burn away, and the coal dust of follow-up introducing is lighted, and realize fractional combustion, produce secondary flame;
Outer sleeve 5: utilize high speed oxygen 4 cooling secondary combustion chamber, carry out combustion-supportingly simultaneously, the unburnt fixed carbon that replenishes secondary combustion chamber's ejection produces three grades of flames at the oxygen that the burner hearth internal combustion needs.Gasification furnace boosts gradually afterwards, and follow-up work is identical with the gasification furnace ignition procedure.
The plasma ignition nozzle is installed on the powder coal gasification furnace.Plasma torch can be by direct current or AC power energy supply, forms isoionic gas and can be any suitable gas such as nitrogen, carbon dioxide, compressed air etc.Plasma generator produces electric arc between two electrodes, plasma forms the great localized hyperthermia of the gradient fire nuclear of T>5000K at the coal nozzle exit, nozzle is continuously carried fine coal, and pulverized coal particle is during by this plasma " fire nuclear ", discharges volatile matter immediately, makes the pulverized coal particle pulverizing of breaking, thereby burning rapidly, carbon is caught fire, reach igniting, stable burning, then the further more coal grain of gasification, therefore increase the effect of plasma torch, and quickened the burning of fine coal.By regulating current strength, control the energy of plasma torch, make it to be complementary with the nozzle fan-out capability, realize controllably igniting, finish the igniting task of gasification furnace.After lighting fine coal, extinguish arcs is utilized automatic extending-contracting apparatus, and the plasma ignition nozzle is withdrawed from from gasification furnace.
As shown in Figure 3, plasma ignition nozzle 2 becomes α ° of angle with gasification furnace 8 coal nozzle plane.Plasma generator 3 is provided with a cover body control system, be responsible for finishing inner each controlled device of plasma generator startup, stop, opening, close and control such as interlock protection.This body control system comprises control system 9, power cabinet 10 and isolating transformer 11.Fire box temperature is low during igniting, enough fuel quantity burning heat releases should be arranged, with smooth combustion.Just throw fuel quantity and should adapt to the requirement that gasification furnace heats up, boosts.Start plasma generator 3 and accessory system 12 thereof according to plasma ignition nozzle ignition procedure.From the compressed air of air compressor machine in the factory 13, be adjusted to setting value through control valve 14, after the fine coal of entering fine coal feeder 16 for batch can 15 from fine coal mixes in blender 17, enter plasma ignition nozzle 2, under the effect of plasma generator 3, produce flame, burn.In order to guarantee the stability of flame, through control valves, enter plasma ignition nozzle 2 from the oxygen 4 of air separation unit, carry out combustion-supportingly, gasification furnace 8 boosts gradually.To note the adjusting of amount of oxygen and the atomizing situation of nozzle after the igniting.When furnace pressure reaches a certain setting value, according to properly mixed oxygen and fine coal, drop into the 1st coal nozzle, after the 1st coal nozzle successfully lighted, stablize a few minutes, gasification furnace heats up, boosts.For different gasification furnaces, according to increasing temperature and pressure control requirement, wait to reach when temperature and pressure requires in the stove that the gasification furnace ignition procedure sets, the diagonal angle drops into the 2nd coal nozzle again, so not only furnace temperature is even, and the diagonal angle light mutually, be beneficial to catch fire stable.Gasification furnace all has flame-observing hole, is furnished with the flame monitoring system, is lighted the post plasma ignition burner and will utilize automatic extending-contracting apparatus to withdraw from when having detected at least 2 coal nozzles, and other nozzles are just lighted a fire by the nozzle of having lighted.4 coal nozzles drop into the most at last, the gasification furnace initial success that feeds intake.
The above only for the usefulness that the utility model is described, but not does any pro forma restriction to the utility model; Person skilled in the relevant technique, under the situation that does not break away from spirit and scope of the present utility model, can also utilize the technology contents of above-mentioned announcement to be changed or be modified as the equivalent example of equivalent variations, therefore, all technical schemes that are equal to also should belong to category of the present utility model, all still belong in the scope of the technical solution of the utility model.