Cautions for Magnesium Oxide Manufacturers in the Process of Desulfurization with Magnesium Oxide

Magnesium oxide is used for desulfurization. Magnesium oxide desulfurization technology has been introduced into many domestic power plants because of its sophisticated technology, abundant material, high desulfurization power, low investment cost, low operation cost and reliable operation. Now some companies have built more than ten sets of magnesium oxide flue gas desulfurization equipment, construction equipment and operation experience are relatively rich. The following focuses on some questions that should be paid attention to in the construction of magnesium oxide desulfurization technology.

1. Pipeline Construction

Magnesium oxide causticization process is a slow and chaotic process. In the process of transportation of magnesium hydroxide slurry from caustic tank to magnesium hydroxide tank and to desulfurization tower, slurry is the coexistence of particles and liquids. It is very simple to form pipeline diameter change, elbow, valve blockage and other places, which causes great potential safety hazards to the system. This requires attention in construction to prevent the potential safety hazards of the system caused by poor construction.

Usually there are four places where the pipeline is blocked, one is the three-way with valve, the other is the elbow with climbing pipeline, the third is the nozzle, and the fourth is the outlet of the pump backstop door.

The reason of blocking slurry in the three-way with valve is that when the pipeline is not together, the residual slurry presents dead point and can not be thoroughly cleaned. With the change of external temperature and other reasons, magnesium oxide crystallizes and finally blockages the pipeline. In the construction period, the best way to deal with this problem is that the shorter the valve is from the tee without affecting the loading and unloading bolts, the better. Sometimes residual liquid can also be brought into the slurry under the scour of slurry.

The pipeline carrying slurry should be cut down as much as possible. If it can't be prevented, the best way is to equip the drain valve under the low side pipeline and flush the pipeline with the high side pipeline equipment, but the barrier doors at the two places must be very close to the opening point.

The blockage of slurry nozzle is very difficult to deal with. The best way is to reduce the number of nozzles, add the number of porous plates or add liquid distributor.

Other pipeline construction usually chooses steel pipe liner or FRP pipeline as slurry transportation pipeline. These two pipelines have high cost. Recently, some manufacturers choose rubber pipeline as slurry transportation pipeline. This kind of pipeline has low cost, convenient maintenance and short direct replacement time. It does not need to wait for the liner again like the liner pipeline, but there are many pipeline brackets.

2. Combination of chimney and desulfurization tower

Due to the late start of desulfurization in China, many power plants are jointly expanding and adding desulfurization equipment to the original boilers, which is often unable to equip because of the severe site.

The combination of chimney and desulfurization tower is a good choice, which can reduce both occupied area and investment. Moreover, if desulfurization equipment is added to the existing boiler renovation, the method of "flue tower integration" is selected, and the anticorrosion treatment of the original chimney and horizontal flue is omitted. Our company has successfully planned the magnesium oxide desulfurization project which combines chimney and desulfurization tower.

3. Anti-corrosion of Magnesium Oxide Desulfurization Tower

Anti-corrosion is an important part of desulfurization. The quality of anti-corrosion of desulfurization tower directly affects the safe operation and desulfurization power of desulfurization system. As far as the current general FRP scale anti-corrosion is concerned, the links that must be paid attention to during construction are as follows:

1) Grinding of weld joint. The polishing of weld directly affects the placing of scales. The thickness of weld must not exceed 2 mm of wall plate. It is necessary for the weld and tower wall to be over-arced.

2) Sandblasting. Many construction teams pay little attention to sand blasting, which usually results in large area of glass flakes falling off and all desulfurization towers corroded. Sandblasting must use quartz sand, particles in the 2 mm distribution, if there is no quartz sand using yellow sand needs to fry sand. The sandblasted panels have metallic luster, and the marks of the sand do not exceed 1.5mm.

4. Equipment of demister

The quality of demister equipment directly affects the quality of flue gas emission. The demister not only removes water and impurities from flue gas, but also directly affects the power of desulfurization.

The quantity and uniformity of scouring water are very important. The amount of scouring water is less. The impurities in mist eliminator are hanging on the mist eliminator, which affects the power of mist eliminator. Severe impurities can block the mist eliminator, resulting in excessive pressure in the tower, high temperature of flue gas, low power of desulfurization, and even the damage of mist eliminator. It is necessary to equip the scouring water system.

High (thick) degree of demister equipment should be moderate, too high and too long will result in low outlet temperature of flue gas and high pressure in the tower; too low (thin), poor demister effect, high outlet pressure and high temperature of flue gas.

5, summary

Magnesium oxide manufacturer in the magnesium oxide desulfurization technology construction, must be combined with the practical application and site conditions, think more that can meet the planning requirements, but also to ensure safe, fast operation, improve the practical application power.