JP2001074229A - Flue gas processor and method of operating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical flue gas treating equipment by using only one drain tank with a heat exchanger. SOLUTION: This processor comprises a GGH heat recovery unit 4 for recovering the heat of exhaust gas discharged from a burner, a desulphurization unit for removing SOx in the exhaust gas at the outlet of the GGH heat recovery unit 4, an SGH 50 for heating the exhaust gas at the outlet of the desulphurization unit with steam and a GGH reheating unit 8 for reheating the exhaust gas at the outlet of the desulphurization unit, wherein these components are sequentially arranged on an exhaust gas channel. The processor further comprises heat transfer tubes 11 and 12 respectively provided in the GGH heat recovery unit 4 and the GGH reheating unit 8 which tubes are communicated with each other, and heating medium circulation lines 13-1 and 13-2 provided with a heating-medium heater 17 for heating the heating medium therein with steam. In this case, drain from the heating-medium heater 17 is pressurized by a heating-medium heater drain recovery pump 57 and is led to an SGH drain tank 54 provided with a heat exchanger through a heating-medium heater drain recovery tank 56. As a result, it is possible to omit the installation of the heating- medium heater drain recovery tank with an expensive heat exchanger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas treatment apparatus and a method of operating the same, and more particularly to a flue gas treatment apparatus suitable for treating exhaust gas discharged from a combustion device such as a boiler and a method of operating the same.

[0002]

2. Description of the Related Art FIG. 3 shows a general system of a flue gas treatment apparatus. In the flue gas treatment device shown in FIG. 3, the exhaust gas discharged from the boiler 1 is introduced into a denitration device 2 and, after nitrogen oxides in the exhaust gas are removed, the combustion air supplied to the boiler 1 in the air preheater 3. Heat exchange with. The exhaust gas is introduced into an exhaust gas heat recovery device (hereinafter, referred to as a GGH heat recovery device) 4, and after heat recovery, most of the dust in the exhaust gas is removed by an electric dust collector 5.

[0003] The exhaust gas is sucked by the attraction fan 6 and then introduced into the wet desulfurization unit 7 where the SO 2 is brought into contact by gas-liquid contact.
x is removed. The exhaust gas at the outlet of the wet desulfurization device 7 is heated by a steam gas heater (hereinafter referred to as SGH) 50,
The mist (liquid atomized fine particles) at the inlet of the exhaust gas re-heater (hereinafter referred to as GGH re-heater) 8 is removed, reheated by the GGH re-heater 8, pressurized by the desulfurization fan 9, and then discharged from the chimney 10. Is discharged.

FIG. 4 shows a conventional GGH system in the system diagram of the above-mentioned smoke exhaust treatment device. The GGH system connects the heat transfer tubes 11 in the GGH heat recovery unit 4 and the GGH reheater heat transfer tubes 12 in the GGH reheater 8 for recovering the heat of the exhaust gas discharged from the combustion device. In the heat transfer tubes 11 and 12 and the communication pipes 13-1 and 13-2.
A heat medium circulating pump 14 circulates a heat medium therein. Here, the GGH heat recovery unit heat transfer tube 11 and the GGH
Generally, a fin tube or the like is used for the reheater heat transfer tube 12 in order to improve the efficiency of heat exchange.

Further, the temperature of the exhaust gas at the outlet of the wet desulfurization unit 7 is raised by the SGH 50, and the mist at the inlet of the GGH reheater 8 is removed.

In FIG. 4, a G thermometer for measuring the temperature of the exhaust gas or the heat medium at the inlet and outlet of each device is provided at the inlet duct 31 and the outlet duct 32 of the GGH heat recovery unit 4, respectively.
A GH heat recovery device inlet exhaust gas thermometer 21 and a GGH heat recovery device outlet exhaust gas thermometer 22 are provided, and the GGH reheater 8 and S
A GGH reheater inlet exhaust gas thermometer 23 and a GGH reheater outlet exhaust gas thermometer 25 are provided in the inlet duct 33 and the outlet duct 34 of the GH 50, respectively. Further, a heat medium circulating pump outlet heat medium thermometer 26 and a GGH heat recovery unit inlet heat medium thermometer 27 are provided in the heat medium communication pipe 13-2, and the GGH heat recovery apparatus outlet heat gauge is provided in the communication pipe 13-1. A medium thermometer 28, a heating medium thermometer 29 at a heating medium heater inlet, and a heating medium thermometer 30 at a GGH reheater inlet are provided.

Further, in order to control the exhaust gas temperature at the outlet of the GGH heat recovery unit 4, a part of the heat medium bypasses the GGH heat recovery unit 4 and the GGH reheater 8 and the communication pipes 13-1 and 13-1.
A heat medium bypass line 15 circulating 3-2 is provided,
According to a signal from the exhaust gas thermometer 22 at the outlet of the GGH heat recovery unit 4, the heat medium circulation flow control valve 41 provided in the heat medium bypass line 15 is controlled so that the exhaust gas temperature at the outlet of the GGH heat recovery unit 4 becomes higher than a set value. The opening is adjusted and the exchanged heat is controlled.

Further, the communication pipe 13-1 or 13-2
In order to cope with various operations such as a load change of the power plant in the heat medium circulation line, a heat medium tank 16 is installed in the heat medium circulation line for the purpose of absorbing the expansion of the heat medium. The heat medium tank 16 is pressurized so that the heat medium is not vaporized in the heat medium circulation line.

On the other hand, in order to make the exhaust gas temperature at the outlet of the GGH reheater 8 equal to or higher than the set value or to set the minimum temperature of the heat medium equal to or higher than the set value, the heat medium heater 17 is connected to the GGH heat recovery unit heat transfer tube 11. It is installed in the connecting pipe 13-1 at the exit,
The heating medium heater 17 is provided with a steam line 20 provided with a steam supply amount adjusting valve 43, and outputs signals from an exhaust gas thermometer 25 at the outlet of the GGH reheater 8 and a heating medium thermometer 27 at the inlet of the GGH heat recovery unit 4. The heating medium heater steam supply amount adjusting valve 43
Is adjusted, and steam for heating the heating medium is supplied to the steam line 20.

The steam supplied to the heat medium heater 17 exchanges heat with the heat medium, and the latent heat is recovered to form a drain, which is recovered in the heat medium heater drain tank 39 with a heat exchanger. Also, S
The steam supplied to the SGH 50 via the GH steam regulating valve 51 exchanges heat with the exhaust gas, and the latent heat is collected and turned into a drain, which is collected in the SGH drain tank 54 with a heat exchanger.

Heat medium heater drain tank 39 with heat exchanger
And the SGH drain tank 54 is provided in the communication pipe 13-2 on the GGH heat recovery unit side, and collects the drain from the heat medium heater 17 recovered in the heat medium heater drain tank 39 and collects the latent heat in the SGH drain tank 54. The steam drain from the SGH 50 recovered by the latent heat is recovered, and the heat is exchanged again with the heat medium, thereby recovering the sensible heat of the drain,
The heating medium heater drain pump 37 and the SGH drain pump 5 are used to lower the temperature of each drain and reuse it in the power plant.
Each is returned to the collection destination (condenser 38 etc.) by 3.

[0012]

In the system configuration of the above-mentioned conventional flue gas treatment system, one heat medium heater drain tank 39 with a heat exchanger and one SGH drain tank 54 with a heat exchanger are required. Therefore, two relatively expensive heat exchangers (heat exchangers attached to the drain tanks 39 and 54) are required.

In addition, when the heat medium heater drain tank 39 with a heat exchanger is omitted, the drain of the heat medium heater 17 is led to the SGH drain tank 54 with a heat exchanger. If the pressure is lower than the SGH drain pressure, the recovery of the heating medium heater drain becomes impossible.

Further, an SGH drain tank 5 with a heat exchanger
4 is omitted, the SGH drain is led to the heat medium heater drain tank 39 with a heat exchanger, and even if only one heat exchanger is used, if the SGH drain pressure is lower than the heat medium heater drain pressure, the SGH drain recovery is not possible. It becomes possible.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an economical flue gas treatment apparatus by using a single drain tank with a heat exchanger.

[0016]

The above objects of the present invention can be attained by connecting the heating medium heater drain to the SGH drain tank via a tank, or connecting the SGH drain to the heating medium drain tank via a tank. Is done.

That is, the first invention of the present invention provides an exhaust gas heat recovery unit (G) for recovering heat of exhaust gas discharged from a combustion device.
GH heat recovery unit), a wet desulfurization device for removing sulfur oxides in the exhaust gas at the outlet of the exhaust gas heat recovery unit, a steam gas heater (SGH) for heating the exhaust gas at the outlet of the wet desulfurization device by steam, and wet desulfurization. An exhaust gas reheater (hereinafter, referred to as a GGH reheater) for reheating exhaust gas at the apparatus outlet is sequentially arranged in the exhaust gas flow path, and an exhaust gas heat recovery unit (GGH heat recovery unit) and an exhaust gas reheater (GGH reheater) In the flue gas treatment device that connects the heat transfer tubes also provided in each of the above and has a heat medium circulating line for circulating the heat medium therein, the heat medium heater that supplies the steam for heating the heat medium is connected to the exhaust gas recirculation line. Provided in the heating medium circulation line on the inlet side of the heater (GGH reheater),
An SGH drain recovery tank with a heat exchanger for supplying steam drain from the GH is provided in the heat medium circulation line on the inlet side of the exhaust gas heat recovery device (GGH heat recovery device), and a heat medium for recovering the steam drain from the heat medium heater is provided. A heater drain recovery tank is provided, and steam drain from the heat medium heater is supplied to the SGH with the heat exchanger through the heat medium heater drain recovery tank.
This is a flue gas treatment device provided with a drain flow path for supplying to a drain recovery tank.

Further, a second invention of the present invention provides a GGH heat recovery device for recovering heat of exhaust gas discharged from a combustion device, a wet desulfurization device for removing sulfur oxides from exhaust gas at an exhaust gas heat recovery device outlet, An SGH for heating the exhaust gas at the outlet of the wet desulfurizer by steam and a GGH reheater for reheating the exhaust gas at the outlet of the wet desulfurizer are sequentially arranged in the exhaust gas channel.
Supplying steam for heating the heating medium in a flue gas treatment device that connects the heat transfer tubes provided in the GH heat recovery unit and the GGH reheating unit, respectively, and has a heating medium circulation line for circulating the heating medium inside. A heat medium heater is provided in a heat medium circulation line on the inlet side of an exhaust gas reheater (GGH reheater), and a heat medium heater drain recovery tank with a heat exchanger for supplying vapor drain from the heat medium heater is connected to an exhaust gas heat recovery device. (GGH heat recovery unit 4) Provided in the heat medium circulation line on the inlet side and provided with an SGH drain recovery tank for recovering steam drain from SGH,
This is a flue gas treatment apparatus provided with a drain passage for supplying steam drain from H to the heat medium heater drain recovery tank with a heat exchanger via the SGH drain recovery tank.

According to a third aspect of the present invention, there is provided the operation method of the smoke exhaust treatment device according to the first aspect, wherein the drain collected in the heat medium heater drain recovery tank is at a height level equal to or higher than a predetermined value. The heat medium heater drain is stepped up by the heat medium heater drain recovery pump to guide the heat medium heater drain to the SGH drain recovery tank with heat exchanger, and the heat medium in the SGH drain recovery tank with heat exchanger is heated by the heat medium heater drain and the SGH drain. This is an operation method of the flue gas treatment device for heating.

According to a fourth aspect of the present invention, there is provided the method for operating a flue gas treatment apparatus according to the second aspect, wherein the drain collected in the SGH drain recovery tank is at a height level equal to or higher than a predetermined value. , The pressure of the SGH drain is increased by the SGH drain recovery pump, the SGH drain is guided to the heat medium heater drain recovery tank with a heat exchanger, and the heat medium in the heat medium heater drain recovery tank with a heat exchanger is heated by the SGH drain and the heat medium heater drain. It is an operation method of the flue gas treatment device.

[0021]

[Action] The pressure, temperature and SGH of the drain from the heating medium heater
Although the pressure and temperature of the drain from the tank are not always the same depending on the operating conditions, the drain is guided to the SGH drain recovery tank with a heat exchanger through the heat medium heater drain recovery tank and the pressure rise of the drain by the heat medium heater drain recovery pump. It is possible to omit installation of an expensive heat medium heater drain recovery tank equipped with a heat exchanger.

[0022] Further, through the SGH drain recovery tank, S
By introducing the drain to the heat medium heater drain recovery tank with a heat exchanger by increasing the pressure of the drain by the GH drain recovery pump, the installation of an expensive SGH drain recovery tank with a heat exchanger can be omitted.

[0023]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a system for collecting the heat medium heater drain into the heat medium heater drain recovery tank 56, and FIG.
The system for collecting GH drain to the SGH drain recovery tank 58 is shown. 1 and 2, members and devices having the same functions as the members and devices described with reference to FIG. 4 are denoted by the same reference numerals, and description thereof is omitted.

First, the GGH system shown in FIG.
A connecting pipe 13-connects the GGH heat recovery unit heat transfer tube 11 in the heat recovery unit 4 and the GGH reheater heat transfer tube 12 in the GGH reheater 8.
1, 13-2, and a system in which the heat medium is circulated by the heat medium circulation pump 14. Also, GGH
A heat medium heater 17 is provided in the connecting pipe 13-1 on the inlet side of the GGH heat recovery heat transfer pipe 11 in order to make the exhaust gas temperature at the outlet of the reheater 8 equal to or higher than the set value.

The steam supplied to the heat medium heater 17 exchanges heat with the heat medium to recover the latent heat, becomes a drain, and is recovered in the heat medium heater drain recovery tank 56. If the drain collected in the heat medium heater drain recovery tank 56 is found to be a drain of a specified value or more by the level meter of the heat medium heater drain recovery tank 56, the heat medium heater drain recovery pump 57 is operated to exchange heat with the heat medium drain. And collected in the SGH drain tank 54 with a container.

The steam supplied to the SGH 50 exchanges heat with the heat medium, and the latent heat is recovered to form a drain. The drain is collected in the SGH drain tank 54 with a heat exchanger and mixed with the heat medium heater drain. SGH drain tank 5 with heat exchanger
Numeral 4 is provided in the connecting pipe 13-2 on the inlet side of the GGH heat recovery unit 4, and the temperature of the collected drain is reduced by exchanging the latent heat recovered in the tank 54 with the heat medium again, The water is returned to a recovery destination such as the condenser 38 by the SGH drain pump 53 for reuse in the power plant.

Next, the system shown in FIG. 2 is the same as the system shown in FIG. 1 in terms of the system configuration of the GGH itself, but the steam supplied to the heating medium heater 17 exchanges heat with the heating medium, and the latent heat is recovered. Then, it is drained and collected in a heat medium heater drain tank 39 with a heat exchanger. Further, the steam supplied to the SGH 50 exchanges heat with the heat medium, the latent heat is recovered to be drained, and is recovered in the SGH drain recovery tank 58.

The drain collected in the SGH drain collection tank 58 has a level meter in the SGH drain collection tank 58.
Is recovered in the heat medium heater drain tank 39 with a heat exchanger and mixed with the heat medium drain.

Heat medium heater drain tank 39 with heat exchanger
Is provided in the communication pipe 13-2 on the inlet side of the GGH heat recovery unit 4, and the temperature of the recovered drain is reduced by exchanging the latent heat recovered in the tank 39 with the heat medium again to lower the temperature of the recovered drain. Is returned to the collection destination by the heat medium heater drain pump 37 for reuse.

[0030]

According to the present invention, even when the pressure and temperature of the drain from the heating medium heater and the pressure and temperature of the drain from the SGH are not the same depending on the operating conditions, the SGH drain tank with the heat exchanger or It is possible to omit the heat medium heater drain recovery tank with a heat exchanger, and there is an effect that one relatively expensive heat exchanger can be used.

[Brief description of the drawings]

FIG. 1 shows a system for collecting a heat medium heater drain in a heat medium heater drain recovery tank according to an embodiment of the present invention.

FIG. 2 shows an SGH drain according to an embodiment of the present invention.
Shows the system for collecting to the drain collection tank.

FIG. 3 shows a system of a general flue gas treatment device.

FIG. 4 shows a conventional GGH system.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 boiler 2 denitration device 3 air preheater 4 GGH heat recovery device 5 electric precipitator 6 induction fan 7 wet desulfurization device 8 GGH reheater 9 desulfurization fan 10 chimney 11 GGH heat recovery device heat transfer tube 12 GGH reheater heat transfer tube 13- 1, 13-2 Communication pipe 14 Heat medium circulation pump 15 Heat medium bypass line 16 Heat medium tank 17 Heat medium heater 20 Steam line 21 GGH heat recovery unit inlet exhaust gas thermometer 22 GGH heat recovery unit outlet exhaust gas thermometer 23 GGH reheating Exhaust gas thermometer at exhaust gas outlet 25 GGH reheater outlet exhaust gas thermometer 26 Heat medium circulation pump outlet heat medium thermometer 27 GGH heat recovery unit inlet heat medium thermometer 28 GGH reheater inlet heat medium thermometer 29 Heat medium heater inlet heat Medium thermometer 30 GGH reheater inlet heat medium thermometer 31 GGH heat recovery unit inlet duct 32 GGH heat recovery unit outlet duct 33 GGH reheater inlet duct 34 GGH reheater outlet duct 37 Heat medium heater drain pump 38 Condenser 39 Heat medium heater drain tank with heat exchanger 41 Heat medium circulation flow control valve 43 GGH heat recovery unit outlet heat medium heater vapor Volume adjusting valve 50 SGH 53 SGH drain pump 54 SGH drain tank with heat exchanger 56 Heat medium heater drain recovery tank 57 Heat medium heater drain recovery pump 58 SGH drain recovery tank 59 SGH drain recovery tank 60 Steam drain from the heat medium heater as heat medium 61. A drain flow path for supplying the SGH drain recovery tank with heat exchanger via the heater drain recovery tank 61 A drain flow path for supplying steam drain from the SGH to the heat medium heater drain recovery tank with heat exchanger via the SGH drain recovery tank

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Saito 6-9 Takaracho, Kure-shi, Hiroshima Babcock-Hitachi Inside the Kure Factory (72) Inventor Masayuki Yamamoto 6-9 Takaracho, Kure-shi, Hiroshima Babcock-Hitachi, Ltd. F-term in Kure Plant (reference) 3K070 DA03 DA09 DA52 DA53 DA76 4D002 AA02 BA02 BA12 BA16 CA06 CA13 EA14 GA03 GB03 HA08

Claims (6)

[Claims] An exhaust gas heat recovery device for recovering heat of exhaust gas discharged from a combustion device, a wet desulfurization device for removing sulfur oxides in exhaust gas at an outlet of the exhaust gas heat recovery device, A steam gas heater for heating the exhaust gas and an exhaust gas reheater for reheating the exhaust gas at the outlet of the wet desulfurization unit are sequentially arranged in the exhaust gas flow path, and heat transfer tubes provided in the exhaust gas heat recovery unit and the exhaust gas reheater, respectively. In a flue gas treatment device provided with a heat medium circulating line for circulating a heat medium therein, a heat medium circulating line on the inlet side of the exhaust gas reheater is provided with a heat medium heater for supplying steam for heating the heat medium. A steam gas heater drain recovery tank with a heat exchanger that supplies steam drain from the steam gas heater is provided in the heat medium circulation line on the exhaust gas heat recovery unit inlet side, and the heat medium heater A heat medium heater drain collection tank for collecting the steam drain of the heat medium heater, and a drain flow path for supplying the steam drain from the heat medium heater to the steam gas heater drain collection tank with the heat exchanger through the heat medium heater drain collection tank. A flue gas treatment device characterized by the following. 2. A flue gas treatment apparatus according to claim 1, wherein a heat medium heater drain pump is provided in a drain passage at an outlet of the heat medium heater drain recovery tank. 3. An exhaust gas heat recovery device for recovering heat of exhaust gas discharged from the combustion device, a wet desulfurization device for removing sulfur oxides in exhaust gas at an exhaust gas heat recovery device outlet, and an exhaust gas at a wet desulfurization device outlet using steam. A steam gas heater for heating the exhaust gas and an exhaust gas reheater for reheating the exhaust gas at the outlet of the wet desulfurization device are sequentially arranged in the exhaust gas channel, and the exhaust gas heat recovery unit and the heat transfer tubes provided for the exhaust gas reheater are connected. In a flue gas treatment apparatus provided with a heat medium circulation line for circulating a heat medium therein, a heat medium heater for supplying steam for heating the heat medium is provided in a heat medium circulation line on the exhaust gas reheater inlet side. A heat medium heater drain recovery tank with a heat exchanger for supplying the steam drain from the heat medium heater is provided in the heat medium circulation line on the inlet side of the exhaust gas heat collector, and the steam drain from the steam gas heater is provided. A steam gas heater drain collection tank for collecting heat, and a drain flow path for supplying steam drain from the steam gas heater to the heat medium heater drain collection tank with a heat exchanger via the steam gas heater drain collection tank. And flue gas treatment equipment. 4. A flue gas treatment apparatus according to claim 3, wherein a steam gas heater drain pump is provided in a drain passage at an outlet of the steam gas heater drain recovery tank. 5. The method for operating a flue gas treatment apparatus according to claim 2, wherein when the drain collected in the heat medium heater drain recovery tank is at a height level equal to or higher than a predetermined value, the heat medium heater drain recovery pump generates heat. The heat medium drain is guided to the steam gas heater drain recovery tank with a heat exchanger by increasing the pressure of the medium heater drain, and the heat medium in the steam gas heater drain collection tank with a heat exchanger is heated by the heat medium heater drain and the steam gas heater drain. Method of operating a flue gas treatment device. 6. The method for operating a flue gas treatment apparatus according to claim 4, wherein when the drain collected in the steam gas heater drain collection tank is at a height level equal to or higher than a predetermined value, the steam gas heater drain collection pump is used to perform steam generation. The gas heater drain is pressurized to guide the steam gas heater drain to the heat medium heater drain recovery tank with a heat exchanger, and the heat medium in the heat medium heater drain recovery tank with a heat exchanger is heated by the steam gas heater drain and the heat medium heater drain. Method of operating a flue gas treatment device.