In addition to the application of new desulfurization tower mist
2016-02-03 09:57:01
Author: Lu Yuegang Cai Yongtao Dong Jianqing
Abstract: with the exception of the sprayer is essential in wet flue gas desulphurization equipment, the widely used of removing fog device comprises a ridge type, plate type and the flue type three. Through the door Fujian power plant desulfurization renovation project operation shows that the new high efficiency demister in flue gas with traditional spray mist eliminator, has its unique advantages and demisting efficiency.
Key words: desulfurization; dehydration; mist; high efficiency demister
1 Introduction
Domestic flue gas desulfurization are mostly adopted the wet process, the core of the device is absorption tower, due to the absorbing reaction tower, most of the spray pipe spray washing, treated flue gas containing a lot of slurry droplet; thus, the fume after washing through the mist eliminator, the purpose of which is to will be in flue gas entrained slurry drops by the impact in addition to mist eliminator blades separated, down except demister blade passage flow tower, lest it with the flue gas excluded tower, the pollution of the environment.
The mist eliminator is essential in wet desulfurization equipment. The widely used demister (including the roof type, plate type and the flue type), but from the currently running in the desulfurization system can found in the mist, mainly has the following two questions.
(1) the demisting efficiency is not high, resulting in the chimney "gypsum rain"
Gypsum rain in mist outlet flue gas carrying liquid drops exceeded, now most of the desulfurization system are not set GGH desulfurization system, due to the low exhaust gas temperature, gas diffusion unfavorable conditions, the flue gas entrained droplets will "gypsum rain" (that is, in the desulfurization tower slurry pool large amounts of gypsum slurry with smoke rises from the chimney mouth smell, serious impact on surrounding environment) is formed at the outlet of a chimney.
The two level plate or roof with the exception of mist eliminator can only guarantee the droplet concentration of exports is not greater than 75mg / Nm3 has been far from being able to meet the goal of mainstream environmental companies and export power plants droplet concentration less than 20mg / Nm3, it is imperative to improve.
(2) misteliminator fouling, wash the demister collapse caused by arrhythmia.
When the addition to the mist eliminator flushing system by absorbing tower level does not affect the according to the normal operation of the program, except for mist eliminator in on-chip scaling are often not timely flushing, intensified the vicious circle, tower arrangement in addition to fog in the sulfite calcium sulfate and calcium accumulation more and more, finally make the demister overwhelmed and collapse.
My company the latest research and development, in addition to mist eliminator blades in Huadian Fujian can Door No. 2 flue gas desulfurization EPC project application, showing in in dehydration and high efficiency of fog. The technology of desulfurization tower dehydration demister has brought new technology theory and application of ideas, to keep pace with the increasingly stringent environmental requirements.
2 overview of desulfurization project
The door No. 2 flue gas desulfurization EPC projects desulfurization project using limestone - gypsum wet desulphurization process, furnace 1 1 tower arrangement has through the transformation of the cancelled desulfurization flue gas bypass and GGH, FGD inlet flue gas volume (standard state, wet basis, alpha =1.397 2143108Nm3/h, maximum smoke temperature 179 DEG C, ceiling absorber except the mist outlet droplet content <75mg/Nm3 Huadian Fujian, the
Due to high content of drop of the liquid outlet, to carry out the transformation of the desulfurization system, taking into account absorption tower has no space transformation. Therefore, the company decided in the absorption tower outlet horizontal flue add a vertical flat plate demister, ensure the horizontal flue flue gas at the outlet of the mist eliminator in the droplet concentration is equal to or less than 20mg / Nm3 (dry, in addition to standard state).
Below is the flue demister layout
Figure 1
Since the original section of the flue flow rate is too high, will expand the size of flue, passing through the demister section of the flow rate decreased to about 5m/s, to ensure the slurry droplet in flue gas can effectively be demister blade interception. The mist eliminator blade layout
Figure 2
The leaves of our company has been reported utility model. The utility model is characterized in that: wet flue gas through the leaves of PP, the entrainment of tiny droplets and leaves many hooks collision, being sucked agglomeration integrated large droplets, under the influence of gravity, and is separated from the flue gas. To solve the problem of fog mist eliminator in low efficiency.
Huadian Fujian the door No. 2 flue gas desulfurization EPC projects desulfurization project officially put into operation, my company commissioned Huadian Electric Power Research Institute (EPRI) for removing mist droplet content of the outlet of the detection, after testing, actual concentration of droplet 16mg/Nm3 (dry, standard state), with horizontal flue in flue gas at the outlet of the mist eliminator in the droplet concentration is equal to or less than 20mg / Nm3 (dry, standard state). Following is the transformation of the former online monitoring data showed that dust content is 23mg/Nm3
图3
The online monitoring data show that after the transformation, the dust content is 8mg/Nm3
Figure 4
After the transformation, found by contrast, chimney outlet dust concentration by 23mg/Nm3 drop 8mg/Nm3, droplet content of 16mg/Nm3 (dry, standard state), meet the design requirements of the mainstream environmental companies and power plants.
3 new high efficiency demister advantage
1, through the reasonable calculation and design, so as to ensure the high demister efficiency, low pressure drop.
2, pipe type demister is arranged in a lower level module, can uniform the flue gas flow field and the removal of large particles slurry droplet.
2, the thickness of the blade design fully consider blade strength requirements, set to 3 mm thick, high pressure flushing and non normal maintenance condition.
3, blade surface is flat and smooth, a module level within the leaves did not set the physical barb, but is designed to form a "fluid hook structure, easy to wash, blade surface is not easy to scale, high removal efficiency of fog; secondary blade module is arranged inside the physical barb to remove very fine slurry particle and ensure demister efficiency; interior of three blade module set multiple physical barb, to remove secondary mist eliminator can not remove the fine slurry particle removal, ensure the demisting efficiency.
4, blade spacing set reasonable and is not easy to be blocked; a span 30mm leaf and secondary spacing 25mm hooked blade, three level spacing 23mm hook, blade.
The optimization of the design of streamline cavity design, 5 nozzle and cavity cavity is larger, the flushing water injection effect is good, and the effective prevention of nozzle clogging.
6, the chemical and physical properties, strong anticorrosion performance.
7, three roof and a tube type in the mist eliminator can let in flue gas at the outlet of the mist eliminator carrying droplet content less than 20mg / Nm3 (dry basis), which can meet the requirements of mainstream environmental companies and power plants.
4.
The model, in addition to the mist eliminator is domestic enterprises in view of the increasingly stringent environmental requirements developed a new technology, with complete independent intellectual property rights, for desulfurization industry provides a new defrosting technology theory and ideas. Because of new high efficiency demister has unique advantages and high efficiency of the mist, a very broad application prospects.