JP3021094B2 - Concentration treatment equipment for wastewater discharged from desulfurization equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sulfur dioxide gas in the combustion exhaust gas (hereinafter, referred to as SOx gas) absorption and a from the viewpoint of prevention of environmental pollution, an alkali agent such as limestone as an absorbent
Concentrate wastewater discharged from the desulfurizer to separate and concentrate
The present invention relates to a concentration treatment device for obtaining water .

[0002]

2. Description of the Related Art Waste water discharged from a desulfurization unit includes gypsum produced in the desulfurization unit and solid components such as limestone that did not contribute to the reaction, hydrogen chloride gas in exhaust gas and calcium and magnesium in an absorbent. Contains various components such as calcium chloride, magnesium chloride and other salt components produced by the reaction with the gas, oxides of metals such as silica and aluminum in the exhaust gas, and combustion ash in the combustion exhaust gas captured in the desulfurization unit. Not only SO2 in exhaust gas
The liquid property of the wastewater is also acidic due to x gas and hydrogen chloride gas, and cannot be discharged to public waters or the like with the same properties, and the treatment is usually performed as described below.

FIG. 3 shows one embodiment of a flow chart of a conventional wastewater treatment facility, and a conventional wastewater treatment method will be described with reference to FIG. The wastewater from the desulfurization unit that is treated by the conventional wastewater treatment equipment, that is, the liquid to be treated, is temporarily stored in the stock solution tank 01 by the line aa. Thereafter, the liquid to be treated is placed on line b.
The solution is supplied to the acid decomposing tank 02 by b, and after decomposing the acid component contained in the same solution, is sent to the solid separation tank 03 for separating the solid component via the line cc. While the liquid to be treated flows through the line cc, an alkali and a coagulant for adjusting the hydrogen ion concentration of the liquid to be treated are injected through the line dd for the purpose of increasing the separation efficiency in the solid separation tank 03. You. In the solid separation tank 03, solids such as limestone, gypsum, and combustion ash in the liquid to be treated are separated, and a liquid having a low solids content (hereinafter referred to as a cleaning liquid) and a liquid having a high solids content (Hereinafter referred to as a concentrated suspension).

The concentrated suspension is supplied to a dehydrator 0 via a line ee.
4 and further separated into water and solids by the dehydrator 04. The water and solids separated by the dehydrator 04 are discharged to the outside of the wastewater treatment facility by lines ff and gg, respectively.

On the other hand, the cleaning liquid from the solid content separation tank 03 is sent to a fine filter 05 such as a sand filter via a line hh.
The solids that could not be separated in the solids separation tank 03 were further separated from the liquid to be treated to improve cleanliness, and then the line ii.
Is stored in the processing liquid tank 06 via the. The treated wastewater in the treatment liquid tank 06 is discharged to the public water area via the line jj (after it is confirmed that the wastewater meets the wastewater standards).

[0006]

As described above, the conventional wastewater treatment equipment has a complicated apparatus configuration, and the operation control method of each apparatus is also complicated. The operation control method is based on the wastewater discharged from the wastewater treatment equipment. In some cases, it is impossible to discharge the wastewater in the treatment liquid tank 06, and in the worst case, the entire system of the wastewater treatment equipment is stopped. Further, as described above, since the apparatus configuration is complicated and the operation control method is complicated, not only the equipment cost and the operation and maintenance cost become expensive, but also the site area required for installing the wastewater treatment equipment becomes large.

The present invention has been made in view of the above-mentioned state of the art, and has as its object to provide a wastewater treatment apparatus capable of solving the above-mentioned disadvantages of the prior art.

[0008]

Means for Solving the Problems The present invention provides the following (1) and
It has the configuration of (2). (1) Concentration treatment of wastewater discharged from a desulfurization unit that absorbs and separates sulfur dioxide gas in combustion exhaust gas with an alkaline agent
An apparatus for storing wastewater discharged from the desulfurization apparatus
Raw water tank, waste water from the raw water tank and the desulfurization
Part of the flue gas before passing through the device is introduced and contacted
Gas-liquid contact to concentrate the wastewater and obtain concentrated wastewater
A gas-liquid contacting device, which drains water collected at the bottom.
Circulating in the space of the section, where the combustion exhaust gas is circulated.
Water and evaporate water to concentrate and concentrate the circulating fluid.
Concentration treatment of wastewater discharged from a desulfurization unit, characterized in that part of the wastewater is discharged as concentrated wastewater
apparatus.

(2) Exhaust gas released from a desulfurization device that absorbs and separates sulfur dioxide gas in combustion exhaust gas with an alkali agent
A water concentration treatment device, which is discharged from the desulfurization device.
A raw water tank for storing wastewater discharged from the
An evaporator for supplying water and evaporating water under reduced pressure;
The wastewater in the can is circulated and the temperature is raised by the heating medium
A drain heater, a condenser for condensing and separating water vapor evaporating from the evaporator, and a vacuum exhaust device provided downstream of the cooler , wherein the drain is maintained under reduced pressure.
Concentrate by evaporating water in the can and discharge as concentrated wastewater
A concentration treatment device for wastewater discharged from a desulfurization device, characterized in that the treatment device is configured to perform the treatment .

That is, the present invention relates to SOx in combustion exhaust gas.
A treatment device for waste water discharged from a desulfurization device that absorbs and separates SOx gas from exhaust gas using an alkaline agent such as limestone as an absorbent from the viewpoint of preventing environmental pollution of the gas , wherein the waste water released from the desulfurization device is a combustion exhaust gas. Or concentrated using steam or other heating medium, and the waste water is further concentrated by condensing waste water containing a large amount of solids and dissolved matter and evaporating condensed water (hereinafter simply referred to as recovered water) or the concentrated waste water. This is a wastewater treatment device that separates and collects the solids obtained and the collected water.

In the present invention, when flue gas is used for evaporating and condensing wastewater discharged from the desulfurization unit, a part of the flue gas before being treated by the desulfurization unit is used as the flue gas and is discharged from the desulfurization unit. that drainage and in direct contact with the gas-liquid contact device, is to concentrate the waste water by evaporating the moisture in the waste water by the sensible heat of the flue gas.

On the other hand, when steam or other heating medium is used, a heating medium generated by another steam generator or the like is used.
The wastewater to be concentrated according to the present invention is charged into an evaporator in which the pressure in the apparatus is reduced, and the wastewater is evaporated by raising the wastewater with the heating medium to concentrate the wastewater.

[0013]

The present invention is a wastewater treatment apparatus for evaporating and condensing wastewater with combustion exhaust gas or steam or other heating medium and separating the wastewater into concentrated wastewater or solids and recovered water. The solid components, salt components, metal oxides, combustion ash and the like in the combustion exhaust gas, which have been formed, are all reduced in concentrated wastewater or solid content and concentrated.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is an explanatory diagram showing an embodiment in which combustion exhaust gas is used as a heat source for condensing wastewater, and FIG. 2 is an embodiment showing a case in which steam is used as the heat source.

In FIG. 1, reference numeral 1 denotes a desulfurizer (not shown).
Raw water tank for temporarily storing wastewater released from
2 is a gas-liquid contact device for bringing waste water and flue gas into direct contact,
Reference numeral 3 denotes a circulation pump that circulates the waste water in the gas-liquid contact device to make it contact the combustion exhaust gas in the gas-liquid contact device.

The waste water from the desulfurization unit is once stored in a raw water tank 1 by a line a, and then supplied to a gas-liquid contact unit 2 through a line b. Line b in the gas-liquid contact device 2
The wastewater supplied from the line c and the circulation pump 3 are circulated by the circulation pump 3 so as to directly contact the combustion exhaust gas supplied from the line e. At the time of this contact, the water in the waste water evaporates due to the heat of the combustion exhaust gas. The temperature of the flue gas corresponding to the heat component required for evaporating the water in the waste water decreases, and the content of the water in the flue gas increases, and the flue gas is discharged out of the system via the line f by the gas-liquid contact device 2. Is done. A processing method is adopted in which the combustion exhaust gas discharged from the gas-liquid contact device 2 is combined with the combustion exhaust gas before being processed again by the desulfurization device, and then combined and processed by the desulfurization device.

On the other hand, the waste water contacts the combustion exhaust gas in the gas-liquid contact device 2, so that the water in the waste water evaporates, and the solid components, salt components, metal oxides and non-burning ash contained in the waste water. Evaporation components are concentrated, and drainage capacity is reduced,
Thereafter, the gas is discharged from the gas-liquid contact device 2 via the line d.

Next, an embodiment in which steam or other heating medium is used will be described with reference to FIG. In FIG. 2, reference numeral 1 'denotes a raw water tank for temporarily storing waste water discharged from a desulfurizer (not shown), 2' an evaporator for evaporating water in the waste water, and 3 'an evaporator in the evaporator 2'. Drain heater for raising the temperature of the waste water, 4 'is a cooler for condensing and recovering the water evaporated in the evaporator 2', 5 'promotes evaporation of the water in the waste water in the evaporator 2' This is a vacuum evacuation device for reducing the pressure inside the evaporator 2 ′ and quickly moving the steam generated in the evaporator 2 ′ to the cooler 4 ′.

In FIG. 2, the waste water from the desulfurization unit is once stored in a raw water tank 1 'by a line a' and then supplied to an evaporator 2 'through a line b'. The wastewater in the evaporator 2 'is supplied to a wastewater heater 3' via a line c '. Steam and other heating media are supplied to the drain heater 3 'through a line e', and the waste water supplied from the evaporator 2 'is heated and discharged out of the system through a line f'. The wastewater whose temperature has been raised by the wastewater heater 3 'returns to the evaporator 2' again via the line d '. Since the pressure inside the evaporator 2 'is maintained at a negative pressure by the evacuation unit 5' and the temperature of the waste water is raised by the waste water heater 3 'as described above, the evaporator 2'
The water contained in the waste water evaporates, and the vapor generated by the evaporation is extracted from the evaporator 2 ′ through the line g ′ and sent to the cooler 4 ′. The steam sent into the cooler 4 'exchanges heat with the cooling medium supplied to the cooler 4' through a line h ', and condenses into moisture (liquid) to be extracted from the cooler 4' through a line j '. And is discharged out of the system. The cooling medium supplied from line h 'to cooler 4' is extracted from line i '. The non-condensable gas after recovering the vapor content in the gas as water (liquid) in the cooler 4 'is sent to the evacuation unit 5' through the line k ', and further through the line l'. It is discharged out of the system.

On the other hand, the concentrated wastewater separated from the wastewater as steam in the evaporator 2 'is extracted from the evaporator 2' via a line m 'and discharged to the outside of the system.

FIG. 1 shows an embodiment of the present invention in which steam or another heating medium is used. The purpose of the evaporator 2 'and the drain heater 3' is to increase the thermal efficiency of the steam or other heating medium. May be plural.

[0022]

According to the present invention, since the components which cannot be discharged to public waters can be concentrated and reduced in volume by concentrating the wastewater to be treated, a complicated apparatus configuration as in the conventional wastewater treatment equipment,
Not only does complicated operation control become unnecessary, but the present invention also simplifies the device configuration, which leads to a reduction in equipment costs and a reduction in the area of the site.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a wastewater treatment apparatus according to the present invention.

FIG. 2 is an explanatory view showing another embodiment of the wastewater treatment device according to the present invention.

FIG. 3 is an explanatory view showing one embodiment of a conventional wastewater treatment facility.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroshi Yoshida, 1-20, Kitakanyama, Odaka-cho, Midori-ku, Nagoya-shi Within Chubu Electric Power Co., Inc. Technology Development Headquarters Power Technology Research Institute (72) Inventor Mamoru Toriyao Midori, Nagoya-shi 1 at 20 Kita-Sanzan, Otaka-cho, Chubu Electric Power Research Institute, Chubu Electric Power Co., Inc. (72) Inventor Hiroyo Tsutsui 2-5-1 Marunouchi, Chiyoda-ku Mitsubishi Heavy Industries, Ltd. Inventor Shinichiro Kotake 2-5-1 Marunouchi, Chiyoda-ku Mitsubishi Heavy Industries, Ltd. ) Inventor: Susumu Okino, 6-22, Kannonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor: Shigeru Nakamura West, Hiroshima-shi 4-6-22 Kannon Shinmachi Hiroshi Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-2-152518 (JP, A) JP-A-1-94920 (JP, A) JP-A-3-8411 ( JP, A) JP-A-63-141601 (JP, A) JP-A-63-224701 (JP, A) JP-A-61-204633 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , (DB name) B01D 53/50 B01D 53/34 B01D 53/77 C02F 1/04

Claims (2)

(57) [Claims] 1. A wastewater discharged from a desulfurization device that absorbs and separates sulfur dioxide gas in combustion exhaust gas with an alkali agent .
A concentration treatment device, wherein the waste gas is discharged from the desulfurization device.
A raw water tank for storing water and drainage from the raw water tank;
Part of the flue gas before passing through the desulfurization unit is introduced
To contact and concentrate the wastewater to obtain concentrated wastewater
A gas-liquid contact device, which is stored at the bottom
The wastewater is circulated to the upper space, and the
Direct contact with combustion exhaust gas to evaporate water and concentrate,
It is configured to discharge part of the circulating fluid as concentrated wastewater.
It is Te effluent concentration treatment device to be released from the desulfurization apparatus according to claim. 2. The wastewater discharged from a desulfurization unit that absorbs and separates sulfur dioxide gas in flue gas with an alkaline agent .
A concentration treatment device, wherein the waste gas is discharged from the desulfurization device.
A raw water tank for storing water and drainage from the raw water tank
An evaporator for supplying and evaporating water under reduced pressure, inside the evaporator
Circulates through the wastewater and raises the temperature with a heating medium.
A water heater, a condenser for condensing and separating water vapor evaporating from the evaporator, and a vacuum exhaust device provided downstream of the cooler, wherein the evaporator can maintain the wastewater under reduced pressure.
Concentrate by evaporating the water inside and discharge as concentrated wastewater
Wastewater concentration treatment device to be released from the desulfurization apparatus characterized by comprising configured to.