JPS6334416A - Pulverized coal combustion process heater - Google Patents

Abstract

PURPOSE:To carry bottom ashes by a combustion waste gas thereby to prevent the same from solidifying. CONSTITUTION:A combustion waste gas from a heating furnace 1 is cooled in an air preheater 6 via a denitrification device 8, and then passes through a bag filter 9. Thereafter, approximately 10% of the waste gas is induced to bottom ash pressure delivery tubes 18 and 19 within a combustion waste gas inlet tube 20. Bottom ashes within combustion chambers 2 and 3 drop into dampers 24 and 25, and are delivered to the bag filter 9 under pressure by the combustion waste gas of the combustion chambers 2 and 3. Upon this occasion, dampers 24, 28 and 29 are closed and dampers 25, 26 and 27 are open, and the bottom ashes within the combustion chamber 3 successively drop into the bottom ash pressure delivery tube 19. When the opening and closing of the damper group are reverse, bottom ashes of the combustion chamber 2 successively drop into the bottom ash pressure delivery tube 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pulverized powder combustion process heating system, and more particularly to an apparatus for discharging bottom ash produced in a heating furnace using combustion exhaust gas.

[Conventional technology] Conventionally, process heating furnaces used in oil refining and petrochemical plants have mainly used oil and/or gas as fuel, but in order to solve energy problems, solid fuels such as coal, petroleum coke, charcoal, and wood have been used as fuel. Progress has been made in the development of heating furnaces that use fuel powder as fuel. In this type of heating furnace, for example, in the case of coal, a large amount of bottom fat is produced after burning the coal.
and fly ash are generated, so these ash must be processed.
For example, as shown in Figure 2, it is necessary to A space heating device is configured.

That is, pulverized coal pulverized by a coal mill is supplied to pulverized coal burner b in heating furnace a, and combustion air is taken in by a push-in method J@machine C, and the pulverized coal is preheated by an air preheater d. is supplied to burner b. In this way, a process fluid such as crude oil or hydrocarbon gas is introduced into the heating furnace a where pulverized coal is burned, and passes through the heat exchanger tube e to a predetermined temperature j (
heated up to.

Incidentally, the combustion exhaust gas discharged from the heating furnace a by the induced draft fan f is denitrified by the denitrification device 9, and then is denitrated by the air preheater 11.
The combustion air is preheated in step d and is then discharged from the stack i through a bag filter h.

This combustion exhaust gas contains fly ash generated during combustion in the heating furnace a, and this fly ash is collected by an ash sump j and a bag filter h provided in the middle of the exhaust pipe, and is then collected using a pressure blower k. The fly ash is sent under pressure to the fly ash silo β.

On the other hand, the bottom ash generated in the heating furnace a is discharged from a bottom ash discharge hopper in the lower part of the heating furnace, and is conveyed by a scraper conveyor n or a jet water stream.

[Problems to be Solved by the Invention] By the way, in this type of heating G11l that heats a process fluid such as crude oil or hydrocarbon gas, the temperature of the exhaust gas at the exit of the combustion chamber is adjusted to prevent thermal decomposition of the process fluid during heating. The temperature is set at about 850 to 950°C, which is lower than that of boilers, etc., and therefore the bottom ash has light fine particles. Therefore, as the above-mentioned scraper conveyor, a water-seal type is mainly used to prevent the bottom ash from scattering. In other words, whether a scraper conveyor or jet water stream is used, bottom ash will be mixed with water, and as a result, bottom ash stored in a silo will solidify and cannot be removed from the silo. It becomes difficult.

Furthermore, the area near the bottom ash discharge hopper garden receives radiant heat from heating furnace a, so it is in a high temperature state.
When trying to convey bottom ash using a water ring scraper conveyor or jet water stream, a large amount of the water used evaporates. Therefore, there is a problem in that a cold fJl device or the like is required to prevent this.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a heating device for a pulverulent combustion process that is capable of conveying bottom seven pieces without using a water seal scraper conveyor or a water jet. .

Means for Solving Problem E] In order to achieve the above object, the pulverized powder combustion process heating device of the present invention heats the process fluid with a heating furnace that uses pulverized powder as fuel, and passes the combustion exhaust gas through a filter to cool the combustion exhaust gas. In an apparatus for recovering fly ash contained in the fly ash, a bottom ash pressure feeding pipe is provided to connect the lower part of the bottom ash discharge hopper of the heating furnace to the upstream side of the filter, and the combustion filtered by the filter is provided. A blower that induces a part of the exhaust gas or air into the bottom ash pressure feed pipe and force-feeds the bottom ash discharged from the bottom ash discharge hopper of the heating furnace into the bottom seven pressure feed pipe to the filter. It is.

[Function] As described above, the bottom ash produced by this type of heating Hfl is in the form of light fine particles, so it can be easily forced out using a blower. Therefore, a part of the combustion exhaust gas or air after being filtered by the blower is transferred to the bottom 7 connected to the lower part of the bottom ash discharge hopper of the heating furnace.
If the bottom ash is drawn into the feed pipe and forced to the upstream side of the filter, the bottom ash is collected together with the fly ash by the filter.

By the way, filters used for fly ash recovery have been conventionally used with heat resistance properties of about 100-100 degrees Celsius, and the combustion exhaust gas induced from the heating furnace is heat-exchanged with an air preheater and has a temperature of 140 to 150 degrees It was configured to pass through a filter after being cooled to a temperature of 100°C. On the other hand, the bottom ash discharged from the heating furnace has a high temperature of about 850 to 950 degrees Celsius, which is the same as the 4A degrees Celsius exhaust gas from the combustion chamber, so if this bottom ash is introduced directly into the filter, the filter will be damaged. .

However, in the present invention, the high temperature bottom ash is pumped using a part of the combustion exhaust gas or air cooled to about 140 to 150°C, so during the pumping process, the bottom ash is cooled by 1JI by the combustion exhaust gas or air.
The temperature will be about 150℃ or less.

Therefore, conventional filters with good heat resistance characteristics can be used as is, and there is no need to use new filters especially for high temperatures. It is sufficient to use about 10% of the amount for pumping bottom ash.

C Embodiment] Hereinafter, an embodiment of the present invention will be described based on a pulverized coal combustion process heating furnace with reference to the attached drawings, but the present invention is not limited to this embodiment.

FIG. 1 is a configuration diagram of a pulverized coal combustion process heating apparatus according to an embodiment of the present invention. In the figure, 1 is a two-bath type heating furnace, in which heat transfer 1! passes a process fluid such as crude oil or hydrocarbon gas through the first and second combustion chambers 2 and 3, respectively. ! 4 and a pulverized coal burner 5.

A forced air blower 7 is connected to the pulverized coal burner 5 via the primary side of a heat storage and regeneration type air preheater 6 in order to supply combustion air. Further, a denitration device 8 is connected to the heating furnace 1 in order to denitrify the exhaust gas after combustion, and an induction conduit II n10 is connected to this denitration device 18 via the secondary side of the air preheater 6 and a bag filter 9. The stack 11 is configured such that the combustion exhaust gas is discharged from the stack 11.

In addition, an ash basin 12 installed in the middle of the combustion exhaust gas exhaust pipe
A conveyor pipe 13 for conveying 7 pieces is connected to the bag filter 9, and a conveyor blower 14 is installed at one end of the conveyor pipe 13, and an ash silo 15 is installed at the other end.

Furthermore, bottom ash pressure feeding pipes 18 and 19 connected to the upstream side of the bag filter 9 are provided at the bottom of the bottom ash discharge hoppers 16 and 17 located at the bottom of each combustion chamber 2 and 3 of the heating furnace 1, respectively. ing. A combustion exhaust gas introduction pipe 2 is branched from the downstream side of the bag filter 9.
0 is connected to the bottom ash pressure feed pipes 18 and 19, and a recirculation blower 2 is installed in the middle of this combustion exhaust gas introduction pipe 20.
1 and a damper 22 for adjusting air volume. This damper 22 is equipped with a differential pressure adjustment device that detects the internal pressure of the combustion chamber 2 of the heating furnace 1 and the internal pressure of the bottom ash pressure feed pipe 18 and controls the opening of the damper 22 so that the differential pressure between these becomes 0! 23
is connected.

Also, dampers 24 and 2 for opening and closing the discharge 1] are provided at the bottom of the bottom ash discharge hoppers 16 and 17, respectively.
dampers 26 and 27 are provided on the upstream and downstream sides of the bottom ash pressure feed pipe 18, respectively, and dampers 28 and 29 are provided on the upstream and downstream sides of the bottom ash pressure feed pipe 19, respectively. Each of these dampers 24 to 29 is connected to an air cylinder (not shown) and a timer (not shown), and each damper is configured to repeat opening and closing operations at a predetermined time t by the timer. Furthermore, the dampers 24, 28, 29 exhibit the same behavior as each other and the dampers 25, 26, 27 exhibit the same behavior as each other, so that when both the dampers 24, 28, 29 are open, the dampers 25, 26, 27 are both The timing is such that when dampers 24, 28, and 29 are all closed, dampers 25, 26, and 27 are all open.

Next, the operation of this embodiment will be explained.

First, pulverized coal pulverized by a coal mill (not shown) or the like and combustion air taken in from the forced air blower 7 and preheated to a predetermined temperature by the air preheater 6 are supplied to the pulverized coal burner 5 to start combustion. will be started.

A process fluid is introduced into the heat transfer tubes 4 of the heating furnace 1 and heated.

Further, the combustion exhaust gas discharged from the heating furnace 1 by the induced draft fan 10 is denitrified by the denitrification device 18, and then is purified by passing through the secondary side of the air preheater 6, and then passed through the bag filter 9. A part (approximately 10%) of the ash is drawn through the combustion exhaust gas introduction pipe 20 to the bottom ash pressure feed pipes 18 and 19 by the recirculation blower [21], and the rest is discharged from the stack 11.

On the other hand, bottom ash generated in the first and second combustion chambers 2 and 3 of the heating furnace 1 falls to the dampers 24 and 25, respectively. Here, assuming that the dampers 24, 28, and 29 are closed and the dampers 25, 26, and 27 are open, the combustion exhaust gas that has been drawn into the combustion exhaust gas introduction pipe 20 is introduced into the bottom ash pressure feeding pipe 18, The bottom ash of the first combustion chamber 2 that has fallen here is forced into the bag filter 9 by the combustion exhaust gas.

At this time, since the dampers 28 and 29 are closed, no combustion exhaust gas is introduced into the bottom ash pressure feed pipe 19.
Further, since the damper 25 is open, the bottom ash generated in the second combustion chamber 3 falls into the bottom ash pressure feed pipe 19 one after another.

Then, when the predetermined time t of the timer connected to each damper has elapsed, the dampers 24, 28, 29 are turned on, and the dampers 25, 26, and 27 are closed.

As a result, the combustion exhaust gas that has been drawn into the combustion exhaust gas introduction ff20 is introduced into the bottom ash pressure feed pipe 19,
The bottom ash of the second combustion chamber 3 that had fallen here is forced into the bag filter 9, and the bottom ash generated in the first combustion chamber 2 is successively transferred to the photomasher pressure feeding pipe 1.
Fall within 8.

In this way, the predetermined vIg! The bottom ash in the bottom ash pressure feeding pipes 18 and 19 is alternately L[
and is collected by the bag filter 9. Further, fly ash in the combustion exhaust gas discharged from the heating furnace 1 is recovered by an ash reservoir 12 and a bag filter 9 provided in the middle of the discharge pipe. The collected bottom ayu and fly ash are then transported to the ash silo 15 through the transport pipe 13 by the transport blower 14.

Furthermore, when the combustion exhaust gas is introduced into the bottom ash pressure-feeding pipes 18 and 19, the dampers 24 and 25 between the bottom ash discharge ports m, respectively, are operated, thereby blowing and handling the combustion exhaust gas for pressure-feeding into the furnace. Although injuries are prevented,
Damper 24. And differential pressure adjustment to completely prevent blow handling due to leaks! 61123 and a damper 22 for ILL adjustment are provided.

That is, the internal pressure of the combustion chamber 2 of the heating furnace 1 and the internal pressure of the bottom ash pressure feed pipe 18 are detected by the differential pressure adjustment 11223, and the opening degree of the damper 22 is controlled so that the differential pressure becomes O. In this way, the pressure difference between the combustion chamber 2 and the bottom ash pressure feed pipe 18 is maintained at zero. By the way, since the internal pressure of combustion chamber 3 is almost equal to the internal pressure of combustion chamber 2,
At this time, the pressure difference between the combustion chamber 3 and the bottom ash pressure feed pipe 19 is also maintained at zero. As a result, the damper 2 for opening and closing the discharge port
Even if a leak occurs at ports 4 and 25, the pressurized combustion exhaust gas is prevented from blowing into the furnace.

[Effects of the Invention] As explained above, according to the present invention, the following excellent effects are exhibited.

(1) Bottom ash can be transported using combustion exhaust gas and collected by a filter together with fly ash.

(2) Since no water is used to transport bottom ash,
The bottom ash does not solidify, making it easy to treat, and there is no need to provide a cooling device to prevent evaporation of the carrier water and damage to the carrier due to radiant heat from inside the furnace.

(3) Extremely economical as combustion exhaust gas is reused.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a pulverized coal combustion process heating apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional example. In the figure, 1 is a heating furnace, 9 is a bag filter, 16 and 17 are bottom ash discharge hoppers, and 18 and 19 are bottom 7
The pressure feed pipe 21 is a recirculation blower. Patent applicant Ishikawajima Haram Kogyo Co., Ltd. Idemitsu Engineering Co., Ltd.

Claims (1)

[Claims] In an apparatus for heating a process fluid using a heating furnace using fine powder as fuel and passing combustion exhaust gas through a filter to recover fly ash contained in the combustion exhaust gas, the lower part of the bottom ash discharge hopper of the heating furnace and the filter are provided. A bottom ash pressure feeding pipe is connected to the upstream side of the bottom ash, and a part of the combustion exhaust gas or air filtered by the filter is induced into the bottom ash pressure feeding pipe and the bottom ash is discharged from the bottom ash discharge hopper of the heating furnace. A pulverulent combustion process heating device comprising: a blower for forcefully feeding bottom ash discharged into a bottom ash pressure feeding pipe to the filter.