JPH053881Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a warming device for a mill.

[Prior Art] Coal-fired boilers take longer to start up than oil/gas-fired boilers, and one of the reasons for this is mill warming.

Coal-fired boilers generally produce
After the primary air is heated through the air preheater, it is guided to the mill through the primary air duct, and the pulverized coal pulverized in the mill is entrained and supplied to the boiler.

In addition, when starting up the mill, oil is burned and the exhaust gas from the oil is used to warm the primary air to perform mill warming. Because the primary air duct is cold, it takes time to warm up the duct, so as shown in Figure 3, after the mill starts warming up, the mill inlet temperature actually rises and the mill outlet temperature reaches a certain level. It takes a long time t to rise to the value A.

[Problems to be solved by the invention] As described above, since mill warming conventionally takes time, DSS (Daily Start Stop) is required especially in coal-fired boilers in recent years.
During operation, there were problems such as time loss and increased mill operating costs for mill warming.

The present invention has been developed by focusing on the problems of the conventional method described above, and aims to shorten the time required for mill warming and to shorten the mill drive time for mill warming.

[Means for Solving the Problems] The present invention is an attempt to solve the above-mentioned technical problems, and includes a hot air duct that preheats primary air through a primary air preheater and is connected to the mill. be done1
The mill inlet of the secondary air duct and the secondary air duct that supplies preheated secondary air to the boiler via the secondary air preheater are connected by a bypass duct with an opening/closing damper for releasing duct preheating air. death,
Further, the mill warming device is characterized in that a mill inlet opening/closing damper is provided between the connecting portion of the bypass duct in the primary air duct and the mill.

[Function] Therefore, in the present invention, prior to warming the mill, a long duct in front of the mill is warmed in advance, and at the same time as mill warming starts, high temperature air can be guided to the mill to perform mill warming.

[Example] An example of the present invention will be described below based on the drawings.

Figure 1 shows an example of the present invention, with boiler 1
A primary air preheater 2 and a secondary air preheater 3 are installed in the middle of the exhaust gas duct 4 to guide the exhaust gas from the primary air fan 5 to preheat the air. part is 1 above
After passing through the primary air preheater 2, the primary air is led to the regulating damper 7 via the hot air duct 6, and the other part of the primary air is directed to the regulating damper 9 via the cold air duct 8, which bypasses the primary air preheater 2. Guided, both adjustable dampers 7, 9
The temperature of the air is adjusted by the adjusting dampers 7 and 9, and the air is sent to the mill 11 through the primary air duct 10, and further supplied to the burner 13 of the boiler 1 via the pulverized coal pipe 12.

Further, after the secondary air from the forced draft fan 14 is preheated through the secondary air preheater 3, it is supplied as secondary air to the burner 13 of the boiler 1 through the secondary air duct 15. It's getting old.

In the above configuration, the inlet of the mill 11 of the primary air duct 10 and the secondary air duct 15 are connected by a bypass duct 17 having an opening/closing damper 16 for releasing duct preheated air. A mill inlet opening/closing damper 18 is provided in the primary air duct 10 between the duct 17 and the mill 11.

In the above configuration, when warming the mill 11, the dampers 9 and 18 are first closed, and the dampers 7 and 16 are closed.
Warming operation starts when the is opened.

Then, 1 from primary air fan 5
The secondary air is heated by the primary air preheater 2, warmed while flowing through the hot air duct 6 and the primary air duct 10, and sent to the boiler 1 via the bypass duct 17 and the secondary air duct 15. It will be done.

Warming of the hot air duct 6 and the primary air duct 10 is performed, and the inlet temperature of the mill 11 (1
When the temperature of the air flowing through the air duct 10 reaches the required temperature, the mill inlet opening/closing damper 18 is opened and the duct preheating air release opening/closing damper 16 is closed to guide hot air to the mill 11 and warm the mill. conduct.

As mentioned above, prior to warming the mill 11, the long ducts 6 and 10 in front of the mill are warmed, so when starting the warming of the mill 11, the mill inlet temperature is Since A is maintained at a required high temperature, the time T required from the start of warming of the mill 11 to raise the mill outlet temperature to the required temperature A can be significantly shortened.

Note that the present invention is not limited to the above-mentioned embodiments, and various changes may be made without departing from the gist of the present invention.

[Effect of the invention] As described above, according to the mill warming device of the present invention, the long duct in front of the mill can be warmed through the bypass duct prior to warming the mill, and thus the mill warming can be started quickly. At the same time, high-temperature primary air can be introduced into the mill, resulting in the excellent effect of significantly shortening the operating time of the mill required for mill warming.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention;
The figure is a graph showing temperature changes during mill warming in the present invention, and FIG. 3 is a graph showing temperature changes during mill warming in the conventional method. 1 is a boiler, 2 is a primary air preheater, 3 is a secondary air preheater, 4 is an exhaust gas duct, 5 is a primary air fan, 6 is a hot air duct, 7 is an adjustment damper, 8 is a cold air duct, 9 is a Adjustment damper, 10 is the primary duct, 11 is the mill, 12 is the pulverized coal pipe, 14
15 is a forced draft fan, 15 is a secondary air duct, 16 is a duct preheating air release opening/closing damper, 17 is a bypass duct, and 18 is a mill inlet opening/closing damper.

Claims (1)

[Scope of utility model registration request] The mill inlet part of the primary air duct connected to the mill is equipped with a hot air duct that preheats the primary air through the primary air preheater, and the mill inlet part of the primary air duct that is connected to the mill and that preheats the secondary air through the secondary air preheater. A bypass duct having an opening/closing damper for releasing duct preheated air is connected to a secondary air duct that supplies the boiler, and a mill is connected between the connection part of the bypass duct in the primary air duct and the mill. A mill warming device characterized by being provided with an inlet opening/closing damper.