JPS6197052A - Device for drying and grinding coal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a coal drying and pulverizing device in a pulverized coal combustion boiler system.

BACKGROUND OF THE INVENTION Conventional coal drying and pulverizing equipment pulverizes coarse coal supplied from the outside into pulverized coal, dries the pulverized coal using drying and pneumatic air supplied from the outside, and burns the pulverized coal. This happened because of the structure that transports it to the boiler.

Problems to be Solved by the Invention According to the above-mentioned conventional configuration, the superficial velocity of the old method pneumatic air in the coal drying/pulverizing device is determined by the amount of drying/pneumatic air, and the amount of raw coal to be supplied is determined by the amount of drying/pneumatic air. Even if the air volume is lowered, the amount of air for drying and pneumatics cannot be significantly reduced in order to maintain the minimum superficial velocity for floating pulverized coal, and the weight ratio of air for drying and pneumatics to pulverized coal ( It was not possible to reduce the value of rA/CJ (hereinafter referred to as rA/CJ) too low. Especially in small coal drying and pulverizing equipment, reducing the A/C increases the pressure drop in the equipment.
The equipment was overfilled with pulverized coal, causing abnormal operation such as vibration of the equipment, making it difficult to operate the equipment at low A/C. On the other hand, when considering the combustion of pulverized coal, it is convenient to have the A/C as small as possible in terms of stability of combustion and suppression of NOx. Operability as a charcoal-fired boiler system (
Town Down) was especially bad.

In addition, in order to prevent abnormal operation due to load fluctuations in the coal drying/pulverizing equipment, there has been a system that uses a hinge system to temporarily store pulverized coal. In addition, due to safety measures for storing pulverized coal, additional blowing equipment (2) was required, which increased costs.

An object of the present invention is to provide an upper drying/pulverizing device that solves all of the above problems.

Means for Solving the Problems In order to solve the above-mentioned problems, the primary drying/pulverizing device of the present invention is provided with crude coal and drying/air blowing air, and pulverizes the coarse coal into pulverized coal. The mill may have a structure including a mill body and a cyclone for recovering the pulverized coal mixed with the drying/air blowing air and conveyed to the outside of the mill body.

Operation In the above configuration, the pulverized coal obtained in the mill body is dried and conveyed by drying and pneumatic air, collected by a cyclone, and supplied to the pulverized coal combustion boiler. therefore,
Even if the A/C of the pneumatic pulverized coal from the mill body is large, the A/C of the pneumatic pulverized coal supplied from the cyclone to the pulverized coal combustion boiler can be sufficiently small, which improves the combustion stability of the pulverized coal combustion boiler. It is possible to simultaneously achieve improvement and prevention of abnormal operation of the mill body.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

In the figure, (1) is the mill body, (2) is the cyclone,
(3) is a proa, (4) is a raw coal supply pipe for supplying raw coal to the mill body (1), and (5) is for supplying drying and pneumatic air to the mill body (1). (6) is a low concentration pneumatic pulverized coal conveying pipe connecting the mill main body (1) and the cyclone (2); (7) is a drying/pneumatic air supply pipe;
(8) is a high concentration pneumatic pulverized coal conveying pipe connected to the lower end of the cyclone (2) marked with #, and (8) is a pipe that connects the upper end of the cyclone (2) and the mill main body (IJ) through the proar (3). This is the extremely low concentration pneumatic pulverized coal return pipe to be connected.

The effects of the above configuration will be explained below.

The raw coal supplied to the mill body (IJ) through the raw coal supply pipe (4) is ground into pulverized coal by the mill body (1).This pulverized coal is It is dried by the drying/pneumatic air supplied to the mill body (1) through the supply pipe (5), and is transported to the cyclone (2) through the low concentration pneumatic fine powder return transport pipe (6). It is desirable that the weight ratio of oxygen in the drying/pneumatic air is 12% or less.
Ordinary air may be used for pulverized coal with a high moisture content. In the cyclone (2), the pulverized coal mixed in the drying/pneumatic air is collected, and this pulverized coal is transferred to the high concentration pneumatic pulverized coal conveying pipe (7).
It is supplied to a pulverized coal combustion boiler (not shown) through the pulverized coal combustion boiler. Generally, the cyclone (2) can collect pulverized coal with a particle size of 10 μm or more, so almost all of the pulverized coal is recovered. On the other hand, the pulverized coal collected by the cyclone (2) is dried and
The pneumatic air is returned to the mill body (1) by the proa (3) through the extremely low concentration pneumatic pulverized coal return pipe (8) for drying and pneumatic feeding.

It is mixed with drying and pneumatic air from the air supply pipe (5) to dry the fineness and convey it.

In this way, the cyclone (2) collects the fine powder and supplies it to the pulverized coal combustion boiler as high concentration pneumatic pulverized coal, so that the A of the low concentration pneumatic pulverized coal carried out from the mill body (1) is reduced. Regardless of the /'C value, pneumatic pulverized coal with a sufficiently low value can be supplied to the pulverized coal combustion boiler, and therefore, it is possible to simultaneously improve combustion stability and prevent abnormal operation of the mill body. In other words, even under low load, the mill body (1
Since the amount of air for drying and pneumatics is small, powdered coal can be supplied to the mill body (
1) Overfilling the mill body (υ) will not cause abnormal operation such as vibration.In addition, the value of the high concentration pneumatic pulverized coal used for combustion is (4)
The amount of raw coal supplied to the mill body (1) through the
The amount of drying and pneumatic air supplied to the mill body (1) through the pneumatic air supply pipe (5) and K can be freely controlled, and the A/C value is 2 even at low loads. It is possible to operate under

In addition, as in the non-implemented example, if the air for drying and pneumatics that collects the pulverized coal in the cyclone (2) is returned to the mill body (υ) and used for circulation, the air for drying and pneumatics can be effectively used. This is preferable because it can be used.This is particularly useful when drying and pneumatic air consisting of special air with an oxygen concentration of 12% by weight or less is used.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, although the present invention can be manufactured at a lower cost than the conventional bottle type, it causes abnormal operation such as abnormal vibration of the mill body due to load change #IK. In addition, pneumatic pulverized coal with a constant A/C value can always be used for combustion regardless of load fluctuations on the mill main body, and large town-down operations and small VC operations can be made possible.

[Brief explanation of the drawing]

The drawing is an overall configuration diagram of an upper drying and pulverizing apparatus in one embodiment of the present invention. (1)...The mill body, (2)...Cyclone agent Yoshihiro Morimoto...The mill body? ...γ(70n

Claims (1)

[Claims] 1. A mill body to which coarse coal and air for drying and pneumatics are supplied and which pulverizes the coarse coal into pulverized coal; A cyclone for recovering the pulverized coal.