JPS60227844A - Treating equipment of stack gas - Google Patents

Abstract

PURPOSE:To improve the performance of a dust collector, to reduce the size of the collector, and to reduce the power consumption of an induced draft blower by providing a device for reducing the temp. of an inlet gas on the upstream side of an air preheater or on the downstream side of an electrical dust collector in the treating equipment of stack gas. CONSTITUTION:Air for fuel is compressed by a forcing blower 1, and fed into a fired furnace along with fuel through an air preheater 3 by steam and an air preheater 4 by gas to obtain a combustion gas which is heat-exchanged at a boiler 5. The temp. of the gas is then decreased by a flue 6, the preheater 4 by gas, and a combustion gas cooler 14 of a gas-gas heat-exchange type, and the cooled gas flows into an electrical dust collector 8. The ash content in the combustion gas is almost completely removed in the collector 8, and the gas is pressurized by an induced draft blower 9. The SO2 and the remaining ash content are removed by a desulfurizer 11, and the gas is then cooled by the combustion gas cooler and discharged from a stack 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to flue gas treatment equipment for a coal-fired boiler plant.

[Conventional technology]

Figure 4 shows a system diagram of the flue gas treatment equipment for a conventional coal-fired boiler plant. In Fig. 4, the coal is fed into the boiler 5, and reacts with the coal fed from the burner (not shown) to become combustion gas.

Flue after heat exchange in boiler 6. Gas air preheater 4, flue 7. Induced through 8 electric precipitators] Pressurized with Iη wind fan 1) and then gas-gas heater 10. After passing through a desulfurization device 11 and heating with a gas-gas heater 10.

It is disposed of through the chimney 13 through the flue 12i.

[Problem that the invention seeks to solve]

As shown in FIG. 5, the temperature is generally around 150 to 130°C, which is limited by the glass side design along the gas flow direction of the conventional system. As shown in FIG. 6, the air resistance of ash containing combustion gas shows a typical extreme value in this width range. For this reason, the ability to collect ash is reduced and the gas temperature is at a high level.
The volumetric flow rate of combustion gas is large, and the movement speed within the electrostatic precipitator is large, reducing dust collection performance1.Therefore, the precipitator requires large-sized equipment, and the induced draft fan 9 is also large, reducing power consumption. increases.

The present invention was made to solve the problems of the conventional method, and it reduces the temperature of the log gas entering the electric precipitator in a manner that does not involve heat loss, improving the performance of the precipitator and making it more compact. The purpose of this design is to reduce power consumption and downsize the induced draft fan.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a flue gas treatment equipment for a coal-fired boiler plant having an air preheater and an electrostatic precipitator. Temperature of log gas entering electric precipitator? The present invention proposes a flue gas treatment facility characterized by being equipped with a device for reducing the amount of smoke.

Hereinafter, one embodiment of the present invention will be explained in detail by way of examples.

〔Example〕

Example 1 FIG. 1 shows a system diagram of one practical example of the present invention.

In FIG. 1, combustion air is pressurized by a forced draft fan 1 and exits through a wind duct 2. Non-steaming air preheater: After passing through the 3° gas air preheater 4 and the outlet air duct, it is fed into the furnace together with fuel from a burner wind box (not shown) and becomes combustible gas. After the combustion gas undergoes complete heat exchange in the boiler 5, it passes through the flue 6. Gas air preheater 4° flue 7. It flows into the electrostatic precipitator 8 via a combustion gas cooler 14 of a gas-gas heat exchange type. Here, after the ash in the combustion furnace gas is almost completely removed, the pressure is increased by the induced draft fan 9, and after SO2 and residual soot and dust are removed by the desulfurization device 11, it is heated by the combustion phosphorus gas cooler 14, and then heated by the chimney 13. more discarded. The steam-type air preheater 3 is a device that heats the air with steam and maintains the low-temperature end metal temperature of the gas-type air preheater 4 at the required temperature. ! !
-11 Perform all heat exchange with low temperature exhaust gas.

At the same time, the electrostatic precipitator lowers the gas temperature and diffuses the desulfurization equipment outlet gas into the atmosphere through the chimney (untreated gas).
This is a so-called non-leak type heat exchanger with a structure that prevents the ash inside from leaking into the desulfurizer outlet gas (processing gas).

FIG. 2 shows a gas temperature diagram for this example.

Example 2 Is Fig. 3 a system diagram of another embodiment of the present invention? show.

In FIG. 3, the same reference numerals as in FIG. 1 indicate devices having the same functions as the device in FIG. This system lowers the gas temperature at the electrostatic precipitator inlet by recovering the heat retained in the combustion gas in low-pressure water condensation.

The device for lowering the electrostatic precipitator inlet gas temperature 7 used in the present invention is not limited to the above-mentioned embodiments, but may be any device that has the function of recovering the retained heat of the electrostatic precipitator inlet gas. The electrical resistance of the ash in the combustion gas is at the highest temperature level, which is 4℃, which can be used with any type of equipment. can be done. The reduction in electrical resistance improves the ability to collect ash, and at the same time reduces the volumetric flow rate of the combustion gas, reducing the flow rate of combustion gas within the electrostatic precipitator and improving the performance of the electrostatic precipitator. The relationship between the electrical resistance of ash and the gas temperature is shown in Figure 6. By lowering the temperature from the level of combustible gas to B, the electrical resistance can be reduced to 1.
]. Also, because the volume flow rate decreases due to the decrease in gas temperature, the power consumption of the induced draft fan decreases as shown in Figure 7. In addition, the low-temperature gas at the exit of the flue gas desulfurization equipment needs to be heated as it diffuses into the atmosphere from the chimney. No additional heating is required.

〔effect〕

As described above, according to the present invention, the performance of the electrostatic precipitator can be improved and the size can be reduced, and the power consumption of the induced draft fan can be reduced and the size can be reduced.
At the same time, it is also possible to achieve the heating temperature of the log gas output from the price removal device.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of one embodiment of the present invention, Fig. 2 is a gas temperature diagram for the embodiment, Fig. 3 is a system diagram of another embodiment of the present invention, and Fig. 4 is a diagram of the conventional system. System diagram of flue gas treatment equipment, No. 5
The figure is a gas temperature diagram for a conventional system, Figure 6 is a graph showing the relationship between gas temperature and electrical resistance, Figure 7 is a graph showing the relationship between gas temperature and vessel, 9. Induced draft fan, 11 Desulfurization equipment, 14 ...Combustion gas cooler, 15..Low pressure feed water heater. 1M Power Matata City - □ Figure 4 Figure 5 Notation: Star Settings and □ Figure 6

Claims (1)

[Claims] In flue gas treatment equipment for a coal-fired boiler plant that has an air preheater and an electrostatic precipitator, a device is installed downstream of the air preheater and upstream of the electrostatic precipitator to lower the gas temperature at the inlet of the electrostatic precipitator. A flue gas treatment facility characterized by: