JPS6141818A - Simultaneous decreasing method of nox-sox-hcl and the like in incinerator - Google Patents

Abstract

PURPOSE:To enable the simultaneous decreasing of NOx, SOx and HCl and save the running cost for water spraying in an incinerator by a method wherein ash and soil water are sprayed in the incinerator. Na, K, Ca, Mg and like are utilized as a dechlorinating agent and a desulfurizing agent. CONSTITUTION:Ash and soil water from a fire grate sewerage sealing tank 14 of a stoker type incinerator 1 is received in an ash sewerage tank 15, a supernatant water is accumulated in an ash and soil water supernatant tank 16. Na, K, Ca, Mg and the like are dissolved as ion in the supernatant water of the ash and soil water. After the dilution of the supernatant water by a industrial water and the like, the supernatant water is pressured by an incinerator inside water spraying pump 17 and water-sprayed into the incinerator 1 from the ash and soil water spraying nozzles 6. Then the water spraying quantity inside of the incinerator is controlled by detecting the NOx concentration contained in an exhaust gas with an NOx concentration detector 19, and the Na, K, Ca and Mg concentration in the spraying water inside of the incinerator is controlled by detecting the SO2, HCl concentration in the exhaust gas with an SO2 concentration detector 22 and an HCl concentration detector. Thereby, simultaneous decreasing of NOx, SOx, HCl contained in the exhaust gas is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to NOx-SOx-HC in an incinerator! ! This relates to a method for simultaneously reducing

Conventional Structure and Problems As a NOx reduction method when burning fuel in an incinerator, a combustion control method that suppresses combustion air is generally used.

In this case, reducing the amount of combustion air causes the temperature inside the incinerator to rise, but methods such as spraying water into the incinerator or sending combustion exhaust gas into the incinerator as a cooling gas can be used to counter this. method, or by cooling the incinerator wall with water pipes, etc.
A method is used to reduce the temperature inside the furnace.

Among these methods, the in-furnace water spray method is commonly used because it has lower equipment costs and equipment operating costs than other methods, and is easy to operate. Water for in-furnace water spraying must not contain substances that may cause clogging of the spray claw μ, such as 88 min, as it is necessary to reduce the spray 4M particle size during in-furnace water spraying. water is required, and more water than that equivalent to industrial water has been used.

However, in addition to the above-mentioned NOx, pollution regulations include VcSOx and HO.
However, the above-mentioned in-furnace water spraying method had a problem in that it could only reduce NOx.

Purpose of the Invention The present invention solves the above-mentioned conventional problems by reducing NO in an incinerator.
The purpose of this invention is to provide a method for simultaneously reducing x-SOx-HCl, etc.

Structure of the Invention In order to achieve the above object, the NO in the incinerator of the present invention
A simultaneous reduction method such as x-5OyvHCl involves spraying ash wastewater into an incinerator with water to reduce Na- contained in the ash wastewater.

It has a structure that uses K, Ca, Mg, etc. as a desalinating agent and a desulfurizing agent, and as a result, it is possible to reduce not only NOx but also SOx and HC/, and also reduce ash. By evaporating the sewage in the incinerator, there is no need to treat ash wastewater, and the cost of draining the in-furnace water spray can be saved.

Examples and effects Hereinafter, one embodiment of the present invention will be described based on the drawings.

In the figure, (1) is the stoker type incinerator, (2) is the fuel input hopper of the stoker type incinerator (1), (3) (4)
(5) is a nine-dry grate installed in the furnace, a combustion grate,
Filter with a post-combustion grate. (6) is a large water spray nozzle μ installed on the ceiling wall of the combustion chamber (7), (8) is a gas cooling chamber connected to the combustion chamber (7), and (9) is a gas cooling chamber ( 8
) is a gas cooling nozzle p installed on the top wall of the building. αO is an air preheater connected to the gas cooling chamber (8), (
6) is a dust collector that collects dust in the exhaust gas that has passed through the air preheater αQ, and @ is a dust collector that collects stray gas from the dust collector (6) using an induced exhaust fan exclusively at the time of the chimney.

On the other hand, (b) is a grate sewage sealing tank that receives the incinerated ash falling from each grate (4) (5) (6) and the gas cooling room (8), and (2) is from the grate sewage sealing tank a4. The taiga water tank (CAQ) is a taiga water tank (CAQ) that stores the supernatant water of the taiga water tank (2), and the supernatant ash sewage collected in the taiga water supernatant tank αQ is passed through the in-furnace water spray pump Q7). It is configured to be guided to the large river water fountain nozzle μ(6). Incidentally, the ash sewage in the large river tank (to) is passed through the ash sewage pump (to).

Appropriately, the grate water sealing tank α→ will be damaged.

(6) is a NOx concentration detector that detects the NOx concentration in the exhaust gas led to the chimney (2), 4 is a computing unit connected to NOx concentration detector 4, iv (a) By controlling the pulp (goods) interposed in the taiga water inlet fins between them, the ratio of taiga water supernatant water in the reactor water spray water is controlled according to the detected flk degree of NOx. This serves to control the amount of water sprayed inside the reactor. (Foundation) is an SO□ concentration detector that detects the SO2 concentration in the exhaust gas led to the chimney.
It functions in the same way as the NOx concentration detector Q field by controlling the valve 4 installed in the water supply fin that supplies water to the NOx concentration detector Q field. In addition to these detectors Q')
A CI concentration detector or an HF concentration detector may be provided.

Although the figure shows a stoker-type incinerator (1), any type of furnace may be used in carrying out the method of the present invention.

That is, any incinerator such as a fluidized bed incinerator, multistage incinerator, rotary kiln incinerator, fixed bed incinerator, etc. may be used. In addition, ash wastewater contains Na + K + Ca.

Any material may be used as long as it contains Mg or the like dissolved or as fine particles.

Next, the operation of such a configuration will be explained.

The incineration ash discharged from the incinerator (1) contains Na and KIC.
It contains a large amount of alkaline earth elements and alkaline earth metals such as alMg, and the content of these elements varies depending on the type of fuel, but the total amount of these elements usually ranges from a few inches to several tens of inches. This part is contained in the incineration ash as compounds such as oxides and carbonates. A portion of these compounds dissolves in the ash wastewater, and Na+, +Ca, Mg, etc. exist as ions or dissolved substances within the range of their solubility products. That is,
The supernatant water of ash wastewater contains Na.

ic, ca + Mg, etc. are dissolved as ions, and it does not contain any foreign matter that could clog the spray nozzle. Therefore, all or part of this supernatant water is diluted with aqua regia, etc., and then the pressure is increased by an in-furnace water spray pump @ and water is sprayed into the furnace from the large river water spray nozzle/L' (6).

If the supernatant water is insufficient, water is supplied to the large river tank (2). Then, as long as soluble Na, K, Ca*Mg, etc. are included in the incinerated ash in the Taiga water tank (5),
Since these ions elute to concentrations limited by their solubility products, large river water species (1119 include Na, K,
Supernatant water in which Ca, Mg, etc. are dissolved will be stored.

The ash wastewater (supernatant water) that has been sprayed with the furnace water evaporates when it comes into contact with the high-temperature combustion exhaust gas, and takes away the latent heat of vaporization, thereby preventing the temperature inside the furnace from rising. Therefore, NOx can be reduced due to synergistic effects such as low air ratio operation, prevention of local combustion in the furnace, and reduction of flame temperature.

In addition, the ejected large river water evaporates inside the reactor, causing N in the input water.
a, +Ca+Mg, etc. float in the furnace as ions or compounds. These ions or compounds are SOx' in the exhaust gas? As a result of reacting with FICI to produce sulfate and chloride, SOx and HCl can also be reduced.

In this case, Na and K that did not react with SOx and HCj'
, Ca.

Most of the carbonate is produced by reacting with ■2,02.
Stable oxide compounds, sulfates, and chlorides are discharged from the furnace and collected as dust in a dust collector (b), making large river water treatment and disposal unnecessary. .

On the other hand, conventionally, when powders such as CaCo), Ca(OH)2, etc. are injected into a furnace, the powders tend to condense among themselves, have poor dispersion in the furnace, and tend to adhere to the furnace walls, etc. is large, so
There was a problem that clinker was easily generated due to low melting point Ca compounds, but in the case of the method of the present invention, Na, +Ca
+Mg etc. are dispersed as ions in the exhaust gas, and their size is much smaller than the aforementioned particles, eliminating the possibility of clinker generation.

By the way, water spray from the large river in the reactor reduces Ri, NOx, and S.
When reducing Ox + HCI, the amount of NOx reduction is related to the amount of water sprayed in the reactor, SOx, HCI
The reduction amount is related to Na1K contained in the input water.
, Ca, Mg, etc. Therefore, NOx, SOx
, to reduce HCl at the same time, NOx concentration detector Q is required.
The NOx concentration in the exhaust gas is detected and the water jet inside the reactor is activated.
In addition to controlling the amount, SO2 concentration detector and HCI
The concentration detector detects the SO2 and HCl concentrations in the exhaust gas and activates the water jet inside the reactor.

Control the Na* K r Ca + Mg concentration in fog water. As a result, NOx + SOx, H
Simultaneous reduction of Cl becomes possible.

That is, the ratio of large river water supernatant water in the reactor water spray water is controlled according to the SOx and HCj concentrations in the exhaust gas.
By controlling the amount of water sprayed in the furnace according to the NOx concentration in the exhaust gas, NOx, HC! ! , SOx can be reduced, and the reduction rate can be controlled.

In addition to the effects of the invention, the method of the present invention provides the following effects.

0 By spraying large river water into the incinerator, NOx
, SOx, and HCl can be reduced simultaneously. In addition, Na r K + C'' + Mg, etc., exist in large river water as ions and very axial particles, so after the spray water evaporates, Na, K, Ca, Mg, etc. are ions and Exists as very small particles, HCI!, SO in exhaust gas
As the contact efficiency with K and K increases, the generation of clinker due to the reaction product produced decreases.

0 Na, K, Ca, Mg, etc. in the incineration ash are desalinating agents,
Since it can be effectively used as a desulfurization agent, SOx in exhaust gas can be
, if you are using drugs to remove HCI,
The amount of this drug can be reduced.

If Taiga water is used as in-furnace water spray water for reducing ONOx, the amount of industrial water used as in-furnace spray water can be reduced.

0 By spraying large river water into the reactor, the Na, +Ca, Mg, etc. contained in the input water are replaced by HCl in the exhaust gas.

Reacts with SOx and others to form sulfates and chlorides. Moreover, unreacted substances react with CO2, O□, etc., and become carbonates and oxides. Since these reaction products are stable and collected as dust in a dust collector, no special post-treatment is required.

0 By spraying large river water into the reactor, the amount of large river water can be reduced, and the amount of sewage that requires large river water treatment can be reduced.

[Brief explanation of drawings]

The drawing is a flow diagram of a stoker type incinerator showing one embodiment of the method of the present invention. (1)... Incinerator, (6)... Taiga water spray nozzle p1
(To)...Input water tank, QQ...Taiga water immersion species

Claims (1)

[Claims] 1. NOx-SOx in an incinerator characterized by water spraying ash wastewater into the incinerator and using Na, K, Ca, Mg, etc. contained in the ash wastewater as a desalting agent and a desulfurizing agent.
- Simultaneous reduction method of HCl etc.