On-line adjustable coal flow distributing device

Abstract

A method of and an apparatus for operating a pulverized coal-fired boiler system, which includes at least one coal pulverizer in flow connection with at least two burners disposed on a boiler enclosure by a coal feed system having a coal pipe junction with a riffle enclosure including a plurality of parallel partition walls forming multiple flow channels from an upstream coal pipe to each of at least two downstream coal pipes and a plurality of individually pivotable vanes upstream of the plurality of partition walls, and controlling the distribution of coal between the downstream pipes by pivoting at least one of the vanes. Preferably a coal flow rate is monitored in the downstream coal pipes and at least one of the vanes is pivoted in response to a measured distribution of the coal flow rate.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method of and an apparatus for operating a pulverized coal-fired boiler system including an on-line adjustable coal flow distributing device. The invention particularly relates to controlling the balance of flows of pulverized coal from a coal pipe to multiple coal pipes by using an adjustable riffle in a coal pipe junction. A riffle is an enclosure including a series of parallel flowchannels with rectangular cross sections, leading coal from an inlet pipe alternatively to each of a plurality of outlet pipes. [0003] 2. Description of the Related Art [0004] In a pulverized coal-fired boiler, particulate coal and primary air flow from one or more pulverizers to multiple coal burners disposed on the boiler enclosure, i.e., on the walls, corners, roof and / or arches, of the boiler. Coal is fed to the burners through a coal feed system comprising multiple coal pipes extending from the pu...

AI Technical Summary

Benefits of technology

[0010] An object of the present invention is to provide a riffle configuration in a simple and reliable method of and apparatus for efficiently controlling the balance of multiple coal flows in a pulverized coal fired boiler system, without significantly increasing the pressure drop of the system.

Problems solved by technology

However, achieving a uniform coal flow distribution to the coal pipes is often a difficult task.

When reaching a coal pipe junction, the rope may be directed mainly to one downstream coal pipe, and the distribution of coal to the burners may therefore become highly unbalanced.

However, such a swirler increases the pressure drop in the coal pipe.

Also, in cases in which an unbalanced distribution of coal is observed, such a swirler cannot be adjusted to correct the flows.

However, channels that are too narrow cause a high flow resistance.

However, in this configuration, a too large imbalance may be caused.

Such a device is, however, quite a complicated construction and prone to wearing.

Images