Introduce a coal powder pipeline balancing device

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Coal powder pipeline balancing system: Under normal circumstances, the distribution of coal powder supplied by one coal grinder to various coal powder pipelines is uneven, with deviations of ±25–30% being quite common. This will result in high levels of CO, unburned carbon, and NOx. Moreover, burners with a large amount of these coal particles during combustion exacerbate slagging and corrosion. ABT’s solution: It utilizes aerodynamic principles to improve the balance between burners, keeping the variation within ±10%, and it does not require on-line measurement devices for air and coal powder, nor computer control of the orifices in the coal powder pipelines. Tower-type distributor: Suitable for all coal grinding systems (except vertical roller mills). It replaces traditional distributors and samplers. Double-inlet, double-outlet ball mills, powder-discharging coal mills, impact coal mills with multiple outlets, vertical spherical and bowl-shaped coal mills. Balance valve: Applicable to any coal powder pipeline and any type of coal grinding system; the balance valve enables online adjustment of the flow rate of primary air and coal powder to the burner ； It has no drawbacks of traditional fixed or adjustable orifice plates. The deviation issue in coal powder pipelines is only partially caused by the differences in the coal powder pipelines, such as their length and the number of elbows on each pipeline. Essentially, it is caused by the accumulation of coal powder inside the coal grinder, and the use of an external balancing device for a specific coal grinder provides the most effective solution. Figure 1 shows that over a wide range of loads, the deviation between tubes remains below ±10%. mhtml:file://L:\Messy Files\Clean Energy Downloads\Advanced Burner Technologies (ABT) Product Brochure\6. Tower Distributor.mht! Figure 1 shows the tower distributor at the outlet of the powder discharge pump. It is worth noting that at the design point, the flow rate deviation is 5.5%, with an improvement factor of nearly 5:1 ； Meanwhile, the pressure drop with a tower-type distributor decreased from 5” to 3.2”. The application of tower-type distributors in impact coal mills, vertically arranged ball mills, and bowl coal mills is the same as that in powder-discharge coal mills. Furthermore, the use of double-inlet double-outlet ball mills simultaneously solves the problems of fuel balance and auxiliary air flow control. In these types of coal mills, if the control and balance of the auxiliary air flow are inaccurate, the variations in the coal powder flow between the tubes will increase. And the tower-type distributor solves all the problems. Since the tower distributor automatically balances the distribution of coal powder and primary air to the coal powder pipes, only one auxiliary air control damper is required. Therefore, the auxiliary air for the burners of each coal grinder can be measured and controlled precisely, with no imbalance in the fuel flow between burners. The complete design of the tower-type distributor is owned by ABT, offering a long product life and high reliability. All surfaces in contact with coal powder are made of corrosion-resistant materials: this ensures an extremely long service life. Furthermore, since the tower-type distributor separates the burner from the coal grinder, disturbances in the coal grinder do not affect the imbalance of the burner, nor the control of combustion efficiency and NOx levels. 1:2 distributor: The simplest form of division is the 1:2 distributor, which is a straightforward version of the tower series. In this case, ABT measurements show that the deviation between tubes is within ±5%. Balance valve: ABT has developed a new type of valve for coal powder pipelines. Traditional orifice plates cause coal dust to accumulate and form vortices, resulting in excessive wear and sparks. The design of ABT eliminates these problems while ensuring long-term reliability. The balance valve is used to reduce the deviation of primary air and coal powder between the coal powder pipelines, thereby helping to control NOx and unburned carbon losses. Although it helps to balance the pressure among the various coal powder pipelines coming from the same coal grinder, in a vertical positive-pressure coal powder system where there is no available control system inside the coal grinder, the main function of the balance valve is to eliminate the areas of coal powder accumulation that form inside the grinder – and these areas are precisely the root cause of coal powder imbalances. The balance valve has two main advantages over traditional fixed and adjustable orifice plates: it can be adjusted both horizontally and vertically, and no accumulation of coal powder occurs downstream of the orifice plate blades. No swirls of coal powder are formed in the coal powder pipeline, which helps to reduce wear inside the pipeline. All balance valves feature ceramic linings, offering a long service life and can be used in any type of coal grinder.