Figures 3 and 4 show the effect on fuel line air balancing when the mill outlet temperature was increased from 128F to 135F. Mill A had coal laid out in the horizontal coal pipe, partly plugging ...
The ratio of coal to water is about 1 to 1 by weight. Coal log pipelines use coal that has been compressed into logs with a diameter 5 to 10% less than the diameter of the pipeline and a length about twice the diameter of the pipeline. The ratio of coal to water is about 3 or 4 to 1.
The CSIRO Division of Minerals has developed and successfully planttested a commercial prototype pulverised fuel (PF) mass flow measurement system on all four boiler feed lines from a single pulverising mill at Bayswater power station, in the Hunter Valley, NSW, Australia. The CSIRO PF mass flow measurement system utilises measurements of the attenuation and velocity of pulsed beams of 60 kHz ...
A flow splitter distributes solid particles flowing in a fluid, such as coal particles flowing in air, through a piping system. The flow splitter includes a divider housing having an inlet configured to connect to an upstream pipe and having an outlet configured to connect to a plurality of downstream pipes,, by way of a divider head.
Ascertain the dirty airflow and fuel flow balances for each mill. Determine the mill grinding performance through coal fineness analysis. Provide a correlation between fuel line "dirty air" velocities and fuel balance. Determine the air to fuel ratio needed for optimum pulverizer performance.
for pipetopipe balance (Graph 3), conditions for coal layout, (Graphs 4 5) mill instability (Graph 6) and clean air conditions when the feeder is shut down and the mill is stripped of coal (Graph 7). Figure 5 — Graph 3: Pipe to Pipe Balance
Fixed orifices are put in shorter pipes to balance velocities / dirty air flow / coal flows. The sizes of the orifices are specified by equipment supplier. Dirty air flow distribution should be within +/ % Coal distribution within +/10% of the average of fuel pipes. Pipe to Pipe Fuel Flows (210 MW) Mills. 2 3
constant airfuel rations at the burner levels. Additionally, the mill and the classifier are adjusted according to the readings of the coal flow and the size spectrum. INTRODUCTION The pulverizedfuel balance, air fuel ratio and particle size spectrum are key parameters for the
coal particles is adjusted as they enter the riffl e. Coal distribution is balanced with very little affect on primary air balance. VCR adjustments for balancing coal distribution are made with the mill in service. VARIABLE ORIFICE The Riley Power variable orifi ce is used for balancing coal, pipe pressure drop and clean airfl ow.
The issue of poor coal distribution is a common problem in vertical spindle mills, adversely effecting unit performance and efficiency. Any deviation from the specified airtofuel ratio in a coal pipe results in a fuel rich or fuel lean zone in the vicinity of a particular burner. In particular, CO emissions and unburned carbon in fly ash ...
A significant improvement in air to fuel ratio between all the fuel piping now allows for the proper usage of an orificing system, if needed, to match the fuel pipe velocities. The SAS MultiOutlet Diffuser is designed to work on all types of pressurized mills with outlet chambers, including Foster Wheeler, MPS Pulverizers, Riley Ball Mills, EL ...
it does not guarantee fuel balance. The fuel balance is dependent upon supplying equal amounts of pulverized coal to each individual coal pipe. Clean air balancing is a mandatory prerequisite to balancing coal flow among coal pipes. 3. Measure on a grid. The pitot tube measures clean air flow in a coal pipe based
In many cases a simple tuning of roll wheel pressure, ball classification in a balltube mill, or air and coalpipe balancing effort can work wonders for unit performance and fuel flexibility.
Balancing Act Pulverized coal ground finely and distributed to the burners is burned in suspension, much like natural gas. To optimize combustion in the furnace, the airfuel mixture can be readily divided equally between coal pipes leaving the mill and will burn much like natural gas when the coal is ground
Pulverized Coal Pipe Testing and Balancing By Richard F. (Dick) Storm, PE The first step in optimizing combustion system performance is balancing the air and fuel flowing through each of the plant's coal pipes—the pipes that convey the air/fuel mix from the pulverizers to the individual burners in the furnace wall.
The reasons for coal hangup to mills can be many, like large raw coal size, jamming of the feeder, jamming of the coal chute from the bunker due to high moisture in the coal, foreign material at raw coal inlet to feeder, etc. Plant responses. The boiler fuel input coming down due to coal flow hangup the mill slowly gets unloaded.
In essence, the performance of a pulverizer is a delicate balancing act between the HGI, fuel fineness, and throughput. 1. A typical MPS89 pulverizer found in many coalfired power plants ...
Current design is for mills with 2, 3, and 4way pipe splits. Coal distribution is heavily affected by inlet maldistribution. Rifflers are used to improve coal flow distribution. Design in progress for pressurized vertical spindle mills CFD modeling completed Laboratory testing completed Prototype field test in 2008
of poor fuel balance. As part of a comprehensive combustion study, the air and coal balance was determined across each mill. This testing was performed utilizing Airflow Sciences' Advanced Coal Flow Measurement System (ACFM). The ACFM (Figure 2) has the capability to follow either the ISO 9931 or the ASMC PTC
The coal is fed to the coal mill through the central inlet pipe, where it is pulverized by a series of large balls separated by two types of rings. ... Scheme of coal mill heat balance. ... Modeling and control of pulverized fuel coal mills. Institution of Electrical Engineers, Thermal power plant simulation and control: Chapter3. 2003. 6399; 3.
The only option available to maintain mill throughput in many plants, beyond burner tuneups, airflow optimizations, and coal pipe balancing or adding more sootblowers, is to optimize or blueprint ...
Coal Imbalance (%). Pipe 1 Pipe 2 Pipe 4 Trials 1 to 6 FCE's Adjusted to Various Settings FCE : Flow Control element Results from a coalflow balancing test on a laboratoryscale pulverizer with four outlet pipes. Beginning with a maximum pipetopipe coal flow imbalance of 12/+17 percent, the imbalance was reduced to less than +2 percent ...
© DZCrusher - كل الحقوق محفوظة
