Method of treating coal gasification wastewater

A technology of coal gasification wastewater and treatment method, which is applied in the fields of gaseous discharge wastewater treatment, degassed water/sewage treatment, oxidized water/sewage treatment, etc., and can solve the problem of not providing

Inactive Publication Date: 2012-02-08
KURITA WATER INDUSTRIES LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented technology helps reduce pollution caused by disposal of used coal-fired boiler flue gases (FG) during combustion processes. It achieves this through removing various harmful substances like sulfur dioxides from exhaust streams produced when burning fossil fuels at high temperatures. By doing so, these contaminants are removed before they enter into our environment's watershed basin where it may cause damage that could be more severe than other methods.

Problems solved by technology

This patents describes various technical problem addressed during processing coal gasifying residue gases including nitrogen, methane, hydrogen chlorides, and others. Existing solutions involve separating these materials individually, leading to increased costs associated therewith. Additionally, existing techniques have limitations when applied alone due to their effectiveness at low concentrations of specific chemicals like CFx/COyand SO2.

Method used

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  • Method of treating coal gasification wastewater
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  • Method of treating coal gasification wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0213] according to Figure 5 The treatment sequence shown is for the treatment of coal gasification wastewater.

[0214] The treatment conditions and the like in each step are as follows.

[0215] (Process (1): Coagulation and precipitation treatment of SS and fluorine)

[0216] according to the following conditions figure 1 Shown based on addition of Ca salt (using Ca(OH) 2 ) coagulation precipitation treatment and based on the addition of Mg salt (using MgSO 4 ) coagulation and precipitation treatment.

[0217] (Ca aggregation condition)

[0218] Ca addition amount = 2500mg / L (as Ca)

[0219] pH=7

[0220] Polymer coagulant: anionic polymer coagulant "Kurifarm PA893" manufactured by Kurita Kogyo Co., Ltd., with an addition amount of 3 mg / L.

[0221] (Mg aggregation condition)

[0222] (Implemented for supernatant water treated with Ca coagulation and precipitation)

[0223] Mg addition amount = 500mg / L (as Mg)

[0224] pH=11

[0225] Polymer coagulant: Kurifloc...

Embodiment 2

[0260] The treated water of the simulated process (2) prepared simulated wastewater with the following water quality, and carried out selenium treatment based on the Al / Ti method under the following conditions. Apart from image 3 This treatment was performed in the same manner except that aluminum and titanium were used as the metal reducing agent.

[0261] (raw water quality)

[0262] T-Se=5mg / L(Se(Ⅵ))

[0263] COD Mn =490mg / L (formic acid=4900mg / L)

[0264] NH 4 -N=4900mg / L

[0265] (based on reducing agent processing conditions)

[0266] Reductant: Al / Ti=1 / 1 (volume ratio)

[0267] Temperature: 65°C

[0268] Dissolution of Al: 1500mg / L

[0269] SV: 5 / hr (relative to Al)

[0270] (agglutination condition)

[0271] pH=7

[0272] Table 2 shows the processing results.

[0273] Table 2

[0274] project

[0275] As can be seen from Table 2, the selenium treatment by the Al / Ti method can sufficiently remove selenium as in the case of using an iron reducin...

Embodiment 3

[0277] according to Image 6 The treatment sequence shown is for the treatment of coal gasification wastewater.

[0278] In steps (1) to (4), the treatment conditions and treatment order of steps (1) to (3) are the same as those in Example 1.

[0279] Wherein, in step (2), H 2 o 2 The addition amount was set at 4000 mg / L, and the reaction time was set at 1 hr.

[0280] In addition, in the step (3), the amount of HCl added was set to be an amount such that the eluted iron amount became 1600 mg / L.

[0281] The treatment conditions of the step (4) are as follows.

[0282] (Process (4): ammonia stripping)

[0283] It implements with respect to the treated water of process (3).

[0284] NaOH was added to the wastewater to adjust the pH to 10, and then it was supplied from the upper part of a packed tower type diffuser filled with cascade ring packing, and steam and air were blown in from the lower part.

[0285] (air stripping conditions)

[0286] G / L=500 (air / wastewater vo...

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Abstract

Treated water with good water quality which can be discharged or reused is obtained by efficiently removing SS, fluorine, cyanogen, selenium, ammonia, and COD components contained in coal gasification wastewater such as gas washing wastewater generated in a coal gasification step. A method of treating coal gasification wastewater comprising steps (1) to (4), wherein the step (1) is performed prior to the step (2): (1) a fluorine removal step in which fluorine is removed by coagulation sedimentation; (2) a cyanogen decomposition step in which cyanogen is decomposed by wet oxidation or thermal hydrolysis; (3) a selenium treatment step in which selenate ions are subjected to a reduction treatment with a metal reductant; and (4) a COD/ammonia removal step in which COD and/or ammonia are/is removed.

Description

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Claims

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Application Information

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Owner KURITA WATER INDUSTRIES LTD
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