JPS61293531A - Treatment of exhaust gas of waste incineration - Google Patents

Abstract

PURPOSE:To remove a harmful substance efficiently by adding the specified assistant and adsorbent to an exhaust gas contg. HCl and Hg or the like, forming a layer of the assistant and the adsorbent on a bag filter of a rear flow and passing the exhaust gas therethrough. CONSTITUTION:Both an assistant 3 such as a mixture of diatomaceous earth and perlite and an adsorbent 4 consisting of 95-99wt.% slaked lime, 1-4 wt.% Na2S and 0.5-2 wt.% Zn are added to an exhaust gas contg. an acidic substance such as HCl, Hg and a compd. thereof produced in an incinerator 5. The mixture is sprayed so that a layer consisting of the assistant 3 and the adsorbent 4 is made uniform from a filter cloth side on the filter cloth of a bag filter 1 in a rear flow and therein HCl and Hg or the like are removed. In such a way, HCl and Hg are removed without increasing the pressure drop.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a comprehensive treatment method for exhaust gas that simultaneously removes harmful substances from the exhaust gas from incineration of waste such as municipal waste.

(Prior Art) Exhaust gas emitted from municipal waste incinerators, etc. contains acidic substances, mainly hydrogen chloride, and mercury and its compounds. To date, these two substances have been removed separately, with hydrochloric acid being removed by wet scrubbers and dry bag filters using alkaline substances, and treatment methods for mercury and its compounds currently being researched by departments. .

(Problems to be Solved by the Invention) The present invention seeks to provide a method for simultaneously removing acidic substances such as hydrogen chloride and harmful substances such as mercury and its compounds from exhaust gas containing these substances.

(Means for Solving the Problems) The present invention uses specific auxiliary agents and adsorbents to simultaneously remove the above-mentioned substances from the exhaust gas using a bag filter. That is, in the present invention, an auxiliary agent that lowers the pressure drop of the bag filter described later and facilitates the removal of attached dust is added to the exhaust gas stream containing acidic substances mainly composed of hydrogen chloride, mercury, and its compounds, and then slaked lime is added to the exhaust gas stream. 95-99% by weight, 1-1% sodium sulfide
An adsorbent of 4% by weight and 0.5-2M % of zinc is added to form a layer of auxiliary agent and adsorbent from the bag filter side in the downstream bag filter, and the exhaust gas is passed through the layer. This is a method for treating waste incineration gas.

The present invention can be advantageously applied to the treatment of incinerator exhaust gas such as industrial waste and sludge in urban areas.

(Structure) An embodiment of the present invention is shown in FIG. In Figure 1,
1 is a bag filter, 2 is a flue spray section, 3 is an auxiliary agent, 4 is an adsorbent, 5 is an incinerator, and 6 is a chimney.

Auxiliary agent 3 and adsorbent 4 to flue spray section 2 in front of bag filter 1
Filter from the right side onto the filter cloth of bag filter 1, auxiliary agent 3, adsorbent 4.
The mixture is sprayed so that the layer becomes uniform, and the exhaust gas from the incinerator 5 passes through this layer.

(Function) The auxiliary agent is used for the purpose of facilitating the pressure loss metal work of the bag filter and the removal of adhering dust. A pre-coating agent is applied as an auxiliary layer to the surface of the filter cloth of a bag filter at a mixing ratio of up to 1, and then a round plate adhesive (1 to 100μ With particles of ca (
oH)2: Na2S: Zn powder at 95~? 9:1
-4: A mixture of 0.5 to 2) is continuously sprayed into the exhaust gas in an amount 5 to 10 times that of the auxiliary agent.

At that time, as the neutralization reaction of hydrogen chloride progresses in the exhaust gas, Jll! ! When the exhaust gas passes between the particles, the following reaction occurs,
Simultaneously removes hydrogen chloride and mercury (or mercury compounds).

2HcI + CeL(OH)24 Gap/2+ 2
H20Hg + Zn → Hg-Zn (Amalgam) HgOI! + Zn −+ Hg−Zn
(Amalgam) + znaz2Ego/2+ Na2S
-*) When the IgS + Nap/Mil/Bag filter becomes high or the adsorption performance of the adsorbent deteriorates, lightly hitting the bag filter will reduce the effect of the adsorbent and reduce the adsorbent layer and adsorbent. The agent layer falls to the bottom. These fall.

After dropping, the auxiliary agent and adsorbent may be added to the exhaust gas again and the same process may be repeated.

The proportions of the components in the adsorbent were determined as a result of many experiments.

(Effects) Harmful substances such as mercury or its compounds and acidic substances such as hydrogen chloride can be removed at the same time as dust by simply spraying an easy-to-use powder adsorbent into the flue. In particular, soda sulfide and zinc powder can be easily dispersed without waste, and mercury or its compounds can also be removed without significantly increasing pressure loss.

That is, it is thought that mercury is mostly composed of its compounds CHgC1, . . . , but the mercury contained therein can also be removed by the metal zinc powder present in the adsorbent.

By attaching the auxiliary agent in advance, the adsorbent layer can be easily removed after the reaction is completed, and the removal operation can be carried out efficiently.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining one embodiment of the present invention. Sub-Agents 1) Meifuku Agent Ryo Hagiwara − Sub-Agent Atsuo Anzai

Claims (1)

[Claims] An auxiliary agent that lowers the pressure drop of the bag filter and facilitates the removal of attached dust, which will be described later, is added to the exhaust gas stream containing acidic substances mainly composed of hydrogen chloride, mercury, and its compounds, and then slaked lime of 95 to 99 wt. %, 1 to 4% by weight of sodium sulfide, and 0.5 to 2% by weight of zinc to form a layer of auxiliary agent and then adsorbent on the downstream bag filter from the bag filter side. A method for treating waste incineration exhaust gas, characterized in that the exhaust gas is passed through.