WO2012124380A1

WO2012124380A1 - Device and method for processing chlorine bypass exhaust gas

Info

Publication number: WO2012124380A1
Application number: PCT/JP2012/051520
Authority: WO
Inventors: 淳一寺崎; 貴寛林田
Original assignee: 太平洋セメント株式会社
Priority date: 2011-03-11
Filing date: 2012-01-25
Publication date: 2012-09-20
Also published as: JP2012188322A; TW201238640A

Abstract

[Problem] To process chlorine bypass exhaust gas by keeping operating costs including maintenance management costs low, and by inhibiting heat loss. [Solution] A device for processing chlorine bypass exhaust gas (1), etc. comprising: a probe (3) which extracts a part (G1) of a combustion gas from a kiln exhaust gas passage from the kiln bottom of a cement kiln (2) to a lowermost cyclone and which cools the extracted combustion gas with a low temperature gas; and a filter type electrostatic precipitator (6) which collects dust (D2) contained in gas (G2) extracted with the probe. This device may also comprise a classifier (5) which separates coarse grain dust (D1) from the extraction gas extracted with the probe, and supply the extraction gas containing fine particles discharged from the classifier to a solid-gas separation device. An inlet gas temperature of the filter type electrostatic precipitator can be 150°C to 500°C.

Description

Chlorine bypass exhaust gas treatment device and treatment method

The present invention relates to an apparatus and a method for treating gas discharged from a chlorine bypass facility for extracting chlorine from a kiln exhaust gas passage from a kiln bottom of a cement kiln to a lowermost cyclone to remove chlorine. About.

Focusing on chlorine, sulfur, alkali, etc., which causes problems such as blockage of preheaters in cement manufacturing facilities, from the bottom of the kiln kiln to the bottom cyclone From the kiln exhaust gas flow path, a chlorine bypass facility for extracting a part of combustion gas and removing chlorine is used.

As shown in FIG. 3, the chlorine bypass facility includes a probe 83 for extracting a part of combustion gas from a kiln exhaust gas passage from a kiln bottom of a cement kiln 82 to a lowermost cyclone (not shown), and a probe 83. A cooling fan 84 that cools the extraction gas G1 by supplying cold air therein, a cyclone 85 as a classifier that separates the coarse dust D1 contained in the extraction gas G1, and fine powder D2 discharged from the cyclone 85 are included. A cooler 86 that cools the extracted gas G2, a cooling fan 87 that supplies cool air to the cooler 86, a bag filter 88 that collects the dust dust D2 in the extracted gas G2 cooled by the cooler 86, and cooling A dust tank 89 that collects the fine powder D2 discharged from the vessel 86 and the bag filter 88.

In the chlorine bypass facility 81 having the above-described configuration, while the part of the combustion gas G1 from the kiln exhaust gas flow path from the kiln bottom of the cement kiln 82 to the lowermost cyclone is extracted by the probe 83, the cold air from the cooling fan 84 is extracted. By cooling with, fine crystals of chlorine compounds are produced. Since the fine crystals of the chlorine compound are unevenly distributed on the fine powder side of the dust contained in the extraction gas G1, the coarse powder D1 classified by the cyclone 85 is returned to the preheater or the like attached to the cement kiln 2 as a cement raw material.

On the other hand, the extraction gas G2 containing the fine powder D2 separated by the cyclone 85 is introduced into the cooler 86, the cooled extraction gas G2 is introduced into the bag filter 88, and the dust D2 contained in the extraction gas G2 in the bag filter 88 is removed. to recover. The dust D2 recovered by the bag filter 88 is stored in the dust tank 89 as chlorine bypass dust having a high chlorine concentration together with the dust discharged from the cooler 86, and then discharged out of the cement firing process and processed.

By the way, in recent years, a high heat-resistant bag filter having a plurality of rod-shaped ceramic tubes formed into honeycomb cells and having heat resistance up to about 900 ° C. has been developed and proposed to be introduced into a chlorine bypass facility (for example, , See Patent Document 1).

In addition, gas with a high chlorine concentration cannot be treated, but an electrostatic precipitator may be used to process a gas with a relatively low chlorine concentration, such as an alkali bypass bleed gas attached to a cement firing device. Proposed.

Japanese Unexamined Patent Publication No. 2009-298777

In the chlorine bypass facility 81, a bag filter 88 is used to collect the fine powder D2. However, the bag filter 88 has a problem in that since the pressure loss is high, the operation cost becomes high, and the maintenance cost is increased because the filter cloth needs to be periodically replaced. In addition, since it is necessary to adjust the temperature of the extraction gas G2 by installing the cooler 86 before introducing the extraction gas G2 to the bag filter 88, maintenance of the cooler 86 is also required. There is also a problem that heat loss occurs due to cooling of G2.

In particular, when the indirect cooling type cooler 86 is used, solidification may occur in the cooler 86 and the capacity may be reduced, or the operation may be difficult due to a closed state. In addition, since recycled fuel is used in the kiln bottom of the cement kiln, part of the burned fuel reaches the bag filter 88, and there is a possibility of clogging the filter cloth of the bag filter 88 or burning the filter cloth. .

On the other hand, when the high heat-resistant bag filter is used, the cooler 86 is unnecessary, and maintenance and management of the cooler 86 and heat loss due to cooling do not occur. Furthermore, there is a problem that the operating cost is high due to high pressure loss.

Therefore, the present invention has been made in view of the above-described problems in the prior art, and the gas discharged from the chlorine bypass facility (chlorine bypass exhaust gas) can be kept low in operating cost including maintenance and management costs. It aims at processing while suppressing loss.

In order to achieve the above object, the present invention is a chlorine bypass exhaust gas treatment apparatus for extracting a part of combustion gas from a kiln exhaust gas passage from the bottom of a cement kiln to the bottom cyclone, It is characterized by comprising a probe for cooling the burned combustion gas with a low temperature gas, and a filtration type electrostatic precipitator for collecting dust contained in the gas extracted by the probe.

According to the present invention, since dust contained in the extraction gas is collected using a filtration type electrostatic precipitator, maintenance of the bug of the bag filter is unnecessary, and pressure loss can be kept low. The operating cost can be kept low.

In the chlorine bypass exhaust gas processing apparatus, a classifier for separating coarse dust from the extracted gas extracted by the probe is provided, and the extracted gas containing fine powder discharged from the classifier is supplied to the solid gas separating apparatus. be able to.

Further, the present invention is characterized in that the chlorine bypass exhaust gas treatment apparatus is used, and the inlet gas temperature of the filtration type electrostatic precipitator is 150 ° C. or more and 500 ° C. or less, preferably 250 ° C. or more and 450 ° C. or less. And According to the present invention, since the outlet gas temperature of the filtration type electrostatic precipitator can be kept high, heat loss can be suppressed even when the exhaust gas system of the cement kiln is returned.

As described above, according to the present invention, the equipment cost of the cooler can be reduced, and the cost for maintenance management of the cooler and the bag filter can be reduced. In addition, it is possible to provide a chlorine bypass exhaust gas treatment apparatus capable of reducing operating costs such as electric power by reducing the number of devices and suppressing pressure loss and suppressing heat loss.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows one Embodiment of the processing apparatus of the chlorine bypass waste gas concerning this invention. It is a schematic sectional drawing for demonstrating the structure and operation | movement of a filtration type electrostatic dust collector used for the processing apparatus of the chlorine bypass exhaust gas of FIG. It is a whole block diagram which shows an example of the conventional chlorine bypass installation.

Next, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 shows a chlorine bypass facility provided with an embodiment of a chlorine bypass exhaust gas treatment apparatus according to the present invention. This chlorine bypass facility 1 is connected from the kiln bottom of a cement kiln 2 to a lowermost cyclone (not shown). From the kiln exhaust gas flow path, the probe 3 for extracting a part of the combustion gas G1 with cooling air from the cooling fan 4 and the coarse dust D1 contained in the extraction gas G1 extracted by the probe 3 are separated. A cyclone 5 as a classifier to be collected, a filtration type electrostatic precipitator 6 for collecting fine powder D2 contained in the extraction gas G2 discharged from the cyclone 5, and an exhaust gas G3 discharged from the filtration type electrostatic precipitator 6 It comprises a fan 7 and the like for supplying the exhaust gas system at the subsequent stage. About the probe 3 and the cyclone 5, since it has the structure similar to what is installed in the conventional chlorine bypass installation, detailed description is abbreviate | omitted.

As the filtration type electrostatic precipitator 6, for example, a filter type electrostatic precipitator manufactured by Furukawa Industrial Systems Co., Ltd. as described in JP 2010-115618 A can be used, as shown in FIG. In the interior 61, there are provided

discharge electrodes

63 and 64 for generating corona discharge, and box-shaped

dust collection electrodes

65 and 66 having both a dust collection function and a filter function, and the dust D in the dust-containing gas Gd is discharged. After being charged by corona discharge generated at the

electrodes

63 and 64 and collected by the

dust collecting electrodes

65 and 66, it is filtered when passing through these dust collecting electrodes (filters). The clean gas Gc from which the dust D has been removed is discharged from the dust collector outlet 62 to the exhaust gas system of the cement kiln 2.

In addition to the synergistic effect of the electrostatic dust collection function and the filter filtration dust collection function, this filtration type electrostatic precipitator 6 has a high dust collection efficiency because the gas passes perpendicular to the filter, and is equivalent to a high-temperature bag filter. Has dust collection efficiency.

Further, the conventional electrostatic precipitator has a problem that the collected dust is re-scattered by striking, but the filter-type electrostatic precipitator 6 is filtered by the

dust collecting electrodes

65 and 66 after the dust is re-scattered. Therefore, the dust concentration at the outlet does not increase significantly.

In addition, stainless steel is used for the

dust collection electrodes

65 and 66, and it can maintain a stable performance with excellent heat resistance, so it can be expected to have a long life and has less pressure loss than a bag filter. This leads to a reduction in operating costs. Furthermore, since the dust collection efficiency is higher than that of a conventional electric dust collector, the size of the main body is small with the same air volume, and space can be saved. The design temperature of the filter type electrostatic precipitator 6 is 320 ° C., the pressure loss of the main body is about 50 mmAq, the design temperature of the conventional bag filter is 150 ° C., and the pressure loss of the main body is about 150 mmAq.

Next, for the chlorine bypass facility 1 having the above-described configuration, a cooling fan is used to extract a part G of the combustion gas from the kiln exhaust gas flow path from the kiln bottom of the cement kiln 2 to the lowermost cyclone with the probe 3. Cool with cold air from 4. As a result, the extraction gas is rapidly cooled to about 550 ° C. or less, and a chlorine compound microcrystal is generated. Since the fine crystals of the chlorine compound are unevenly distributed on the fine powder side of the dust contained in the extraction gas G1, the coarse powder D1 classified by the cyclone 5 is returned to the preheater attached to the cement kiln 2 as a cement raw material.

The extraction gas G2, which contains the fine powder D2 separated by the cyclone 5 and is about 400 ° C., is introduced into the filtration type electrostatic precipitator 6 to collect the fine powder D2. The dust D2 collected by the filtration type electrostatic precipitator 6 is discharged out of the cement firing process and processed.

On the other hand, the exhaust gas G3 discharged from the filtration type electrostatic precipitator 6 and supplied downstream by the fan 7 is an exhaust gas system of the cement kiln 2, that is, an outlet side of a fan (IDF) that induces the exhaust gas of the cement kiln 2, The preheater attached to the cement kiln 2 can be returned.

DESCRIPTION OF SYMBOLS 1 Chlorine bypass facility 2 Cement kiln 3 Probe 4 Cooling fan 5 Cyclone 6 Filtration type electric dust collector 7 Fan 61 (of the filtration type electric dust collector) Interior 62 (of the filtration type electric dust collector)

Gas outlet

63, 64

Discharge Electrodes

65, 66 Dust collection electrode

Claims

A probe for extracting a part of the combustion gas from the kiln exhaust gas passage from the bottom of the kiln of the cement kiln to the lowermost cyclone, and cooling the extracted combustion gas with a low temperature gas,
An apparatus for treating chlorine bypass exhaust gas, comprising: a filtration-type electrostatic precipitator that collects dust contained in gas extracted by the probe.
A classifier for separating coarse dust from the extracted gas extracted by the probe;
The chlorine bypass exhaust gas treatment apparatus according to claim 1 or 2, wherein a bleed gas containing fine powder discharged from the classifier is supplied to the solid gas separation device.
A chlorine bypass exhaust gas treatment method, wherein the chlorine bypass exhaust gas treatment device according to claim 1 or 2 is used, and an inlet gas temperature of the filtration electrostatic precipitator is set to 150 ° C or higher and 500 ° C or lower.