JPH06142507A - Regenerating method for activated coke - Google Patents

Abstract

PURPOSE:To control consumption of activated coke by performing regeneration of activated coke, separating and recovering harmful gas components and heavy metals adsorbed on activated coke and repeatedly using regenerated activated coke in the case of treating exhaust gas. CONSTITUTION:Superheated steam is supplied into a regeneration tower 1 which is packed with activated coke 2 and is in the state of low oxygen. Harmful gas components and heavy metals adsorbed on the surface of activated coke 2 are reduced by heating activated coke 2 by the superheated steam in the reducing atmosphere of low oxygen. Thereby activated coke 2 is regenerated. Regenerating steam discharged from the regeneration tower 1 is led to a cooler 5 and condensed. Condensate is led to a precipitation tank 6, separated into separating liquid being an acidic solution and heavy metals. Heavy metals are settled and recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating active coke used for adsorbing and removing SO _X , Hg and the like contained in exhaust gas from an incinerator or the like.

[0002]

2. Description of the Related Art Conventionally, exhaust gas discharged from an incinerator is discharged to the outside of the system through the following treatment procedure for reuse of thermal energy and removal of harmful gas.

Exhaust gas discharged from the incinerator is first led to a waste heat boiler to recover the thermal energy of the exhaust gas as steam. The steam obtained from the waste heat boiler is used as a heat source for heating and supplying hot water inside and outside the treatment plant and as a driving force for a steam turbine that drives a generator.

The exhaust gas that has passed through the waste heat boiler is guided to the gas cooling chamber, and the exhaust gas is cooled to an appropriate temperature by the jet water sprayed into the gas cooling chamber. Guides cooled exhaust gas into the bag filter, and spraying the slaked lime in the flue gas in the middle of the path, a harmful gas in the exhaust gas SO _X
Hydrogen chloride or the like is reacted with slaked lime Ca (OH) ₂ , and the reaction product is removed by a bag filter.

Further, the exhaust gas that has passed through the bag filter is guided to a desulfurization / denitration apparatus, and the activated coke filled in the desulfurization / denitration apparatus removes harmful gases such as SO _X and heavy metals such as Hg and dioxins contained in the exhaust gas. Adsorbed and removed.

[0006]

However, in the above-mentioned conventional structure, the adsorbing capacity of the active coke deteriorates with the lapse of time, so that the coke needs to be replaced periodically, and the running cost is high. Also, since used activated coke has adsorbed SO _X , Hg, etc. on its surface, if it is directly subjected to melting treatment, etc.
O _X and Hg, etc. will be included, which is a problem.

The present invention solves the above problems, and an object of the present invention is to provide a method for regenerating active coke in which SO _X and Hg adsorbed on the active coke are separated and recovered, and the active coke is reused. .

[0008]

In order to solve the above-mentioned problems, the method for regenerating active coke according to the present invention comprises supplying superheated steam into a regeneration tower in a low oxygen state filled with used active coke to superheat it. By heating the active coke in a reducing atmosphere of low oxygen with steam, the harmful gas components and heavy metals adsorbed on the surface of the active coke are reduced to regenerate the active coke, and the regenerated steam discharged from the regeneration tower is guided to the cooler. The condensed liquid is introduced into a settling tank, and the condensed liquid and the heavy metal are settled and recovered to be collected.

The superheated steam is obtained by reheating the steam generated in the waste heat boiler by using the exhaust gas of the incinerator as a heat source and reheating it in the heater by using the exhaust gas of the incinerator introduced separately from the waste heat boiler. Is.

[0010]

With the above structure, it is possible to regenerate the active coke and separate and collect the harmful gas components and heavy metals adsorbed to the active coke, and use the waste heat of the incinerator as the superheated steam for regenerating the active coke. Therefore, it is not necessary to separately provide a heat source for generating superheated steam. Therefore, when treating the exhaust gas, by repeatedly using the regenerated activated coke, it is possible to suppress the consumption of activated coke, and by effectively utilizing the waste heat of the incinerator for regenerating the activated coke, The efficiency of energy use can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a regeneration tower 1 is filled with used activated coke 2, which is used in a desulfurization / denitration process in an exhaust gas treatment process of an incinerator and acts as a catalyst and It adsorbs and removes SO _x , which is a harmful gas, and Hg, which is a heavy metal.

A superheated steam supply pipe 3 is provided in communication with the regenerator 1, and the superheated steam sent to the superheated steam supply pipe 3 uses the exhaust gas of the incinerator as a heat source for the steam generated in the waste heat boiler as a heater. At 300 to 500 ° C., the exhaust gas of the incinerator is introduced into the heater separately from the waste heat boiler and used as a heat source. Further, the steam heated by the heater may be exhaust steam after the steam generated in the waste heat boiler is used in the steam turbine.

A regeneration steam discharge pipe 4 is provided in communication with the top of the regeneration tower 1, and the regeneration steam discharge pipe 4 discharges the regeneration steam used in the regeneration tower 1. It communicates with 6.

The operation of the above structure will be described below. The regeneration tower 1 is filled with used activated coke 2 and the inside of the regeneration tower 1 is maintained in a low oxygen state. In this state, superheated steam is supplied from the superheated steam supply pipe 3, and the active coke 2 is heated in the low oxygen reducing atmosphere by the superheated steam.

As a result, the harmful gas component SO _X and the heavy metal Hg adsorbed on the surface of the active coke 2 are reduced, and Hg and sulfuric acid are released from the active coke 2 as steam to regenerate the active coke 2. Reduced Hg
The sulfuric acid and sulfuric acid are discharged to the outside of the regeneration tower 1 together with the regeneration steam.

The regenerated steam discharged from the regenerator 1 is introduced into the cooler 5 through the regenerated steam discharge pipe 4, and the regenerated steam, Hg vapor and sulfuric acid vapor are condensed in the cooler 5. This condensate is introduced into the settling tank 6, and is separated and separated into a separated liquid that forms an acidic solution in which sulfuric acid is dissolved and metal Hg, and is collected.

The activated coke 2 regenerated in the regeneration tower 1 is passed through a vibrating screen 7 and separated into a solid active coke 8 having an appropriate particle size and a powdered active coke 9. The solid active coke 8 is reused in the desulfurization / denitration process, and the powdered active coke 9 is used as a fuel or melted.

[0018]

As described above, according to the present invention, it is possible to regenerate the active coke and to separate and recover the harmful gas components and heavy metals adsorbed to the active coke, and to regenerate the active coke when treating the exhaust gas. By repeatedly using, the consumption of active coke can be suppressed. Moreover, since the superheated steam for regenerating the active coke is obtained by using the waste heat of the incinerator, it is not necessary to separately provide a heat source for generating the superheated steam, and the waste heat of the incinerator is used for regenerating the active coke. By effectively using the, it is possible to improve the energy use efficiency.

[Brief description of drawings]

FIG. 1 is a schematic view showing a step of regenerating active coke in an example of the present invention.

[Explanation of symbols]

 1 Regeneration tower 2 Activated coke 3 Superheated steam 5 Cooler 6 Precipitation tank

Claims (2)

[Claims] 1. Adsorption on the surface of active coke by supplying superheated steam into a regeneration tower in a low oxygen state filled with used active coke and heating the active coke in a reducing atmosphere of low oxygen by the superheated steam. The activated gas is regenerated by reducing the harmful gas components and heavy metals, and the regenerated steam discharged from the regeneration tower is introduced into a cooler for condensation, and the condensate is introduced into a settling tank to form an acidic solution of the separated liquid and heavy metal. A method for regenerating activated coke, which comprises collecting the coke by sedimentation. 2. The superheated steam is obtained by reheating the steam generated in the waste heat boiler by using the exhaust gas of the incinerator as a heat source, in the heater by using the exhaust gas of the incinerator introduced separately from the waste heat boiler. The method for regenerating active coke according to claim 1.