Why does the CFB tube abrasion cannot be eradicated?

CFB boiler is affected by wear and tear leakage, almost with the birth of CFB boiler has been existing. Over the years, CFB boiler technology has made great breakthroughs, and various technologies related to cyclic sulfide bed have made rapid progress, but only the boiler furnace wear problem has not been eradicated. So why has the problem of wear and tear remained fundamentally unresolved for so long?

The reasons need to be explained from the subjective and objective aspects, from the objective factors:

I. combustion characteristics:

1. The use of coal is complex, changeable and inferior. CFB boilers often burn inferior fuels such as bituminous coal, lignite, gangue, garbage, biomass and refractory solid fuel, etc., with very high ash content;

2. Cyclic combustion, ash and slag, large particle fuel, inevitably in the furnace circulation, and uninterrupted wear to the boiler;

Ii. Maintenance environment decision：

1. The heating surface area in the furnace is very large, and the amount of scaffolding construction in the furnace is very large for daily maintenance. The inspection and maintenance of wall thickness are also based on regional sampling measurement, which is quite tedious and cannot be done in every aspect, and the slightest negligence may leave safety risks.

2. Abrasion and leakage events in the furnace are all occurred suddenly in the running boiler, without any warning in advance. In addition, in the running boiler, rapid combustion reaction continues to occur in the furnace. High temperature, high pressure, high wind speed and high concentration of doped material particles make it impossible to conduct effective real-time monitoring and feedback.

3. Deep inside the furnace in the worn area, there are problems in the confined space that cannot be timely detected, maintained and dealt with;

Iii. Operation demand decision:

Because each shutdown of the boiler is corresponding to a huge loss of benefits, so the boiler has to take a long period of operation, sometimes even under high load long period of operation.

Long cycle operation allows the boiler to achieve regular maintenance in the theoretical maintenance cycle, and high load operation will even increase the wear to more than ten times.

From the perspective of subjective factors:

Previously, mainstream solutions and ideas were too passive:Before the mainstream of the way to deal with wear cladding, spraying, pouring materials are passive thickening type anti-wear, can not fundamentally solve the wear, can only delay the time of wear leakage, only to alleviate the role. However, the construction time of these methods is long, the maintenance is troublesome, and the protection effect is short, which is no more than one year and requires repeated construction and maintenance every year.

So, why not change the passive into active, and develop an active and efficient anti-wear method?

As a Chinese saying goes, "yu the great is better to control the flood than to block it".

According to this subjective thinking, we have carefully studied and concluded the main causes of wear leakage: high-speed adherent flow and local eddy current

The heat-conducting grille anti-wear technology developed by our company further optimizes the flow field on the surface of the water-cooled wall to eliminate local eddies on the basis of eliminating high-speed adherent flow. In addition, the anti-wear grille can eliminate the cold isolation effect, realize the speed control function of the wall-mounted flow, and keep the flow rate of the wall-mounted materials within an ideal range to improve the heat transfer efficiency. From the current use of the effect, there is no problem with the grid five years.

Cold insulation effect: when the adherent flow falls along the water wall, the material close to the wall remains unchanged and the lowest temperature affects the efficient heat transf