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Low-cost and zero-discharge treatment process for MTO alkaline washing waste alkali liquor

A treatment process and waste lye technology, which is applied in the field of low-cost MTO alkali washing waste lye zero discharge treatment process, can solve the problems of long biological treatment process, large floor area, high operating costs, etc., to avoid the use and Effects of equipment corrosion, ease of process operating conditions, reduction of investment and land occupation

Active Publication Date: 2017-12-08
SINOPEC ENG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The biological treatment process inevitably has the disadvantages of long process, large floor area, low treatment efficiency, high operating costs (requires regular supplementation of bacteria), etc., which limits the application of biological methods to a certain extent
At the same time, the use of biological methods will produce a certain amount of sludge, and the treatment of sludge is becoming more and more restricted.
[0009] In summary, for MTO waste lye, the current various treatment methods have many problems such as inapplicability, large investment, high operating cost, and low efficiency.

Method used

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  • Low-cost and zero-discharge treatment process for MTO alkaline washing waste alkali liquor

Examples

Experimental program
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Effect test

Embodiment 1

[0036] A stream of waste lye discharged from the bottom of the MTO alkali washing tower, wherein: COD is 8000mg / l, Na 2 CO 3 The concentration is 7.6 wt%, the NaOH concentration is 1.6 wt%, the free oil is 250 mg / l, the methanol concentration is 0.03 mol%, and the dimethyl ether concentration is 0.01 mol%.

[0037] use figure 1 The processing flow chart shown, the processing steps are as follows:

[0038] (1) Oil washing and degassing: Utilizing the difference in solubility, washing oil is used to wash MTO waste lye, and by standing and stratifying, the washing oil and waste lye are separated, and the oil entrained in waste lye is initially removed Carry out decompression treatment to the waste lye after oil washing to reduce its pressure from 1.4MPaG to 0.05MPaG; through oil washing and degassing, the oil content and dissolved organic matter content in the waste lye are reduced to about 4000mg / l;

[0039] (2) The storage tank is left standing: the spent lye after prelimina...

Embodiment 2

[0044] A stream of waste lye discharged from the bottom of the MTO alkali washing tower, wherein: COD is 15000mg / l, Na 2 CO 3 The concentration is 6.7wt%, the NaOH concentration is 1.5wt%, the free oil is 1000mg / l, the methanol concentration is 0.04mol%, and the dimethyl ether concentration is 0.02mol%.

[0045] use figure 1 The processing flow chart shown, the processing steps are as follows:

[0046] (1) Oil washing and degassing: Utilizing the difference in solubility, washing oil is used to wash MTO waste lye, and by standing and stratifying, the washing oil and waste lye are separated, and the oil entrained in waste lye is initially removed Carry out decompression treatment to the waste lye after oil washing to reduce its pressure from 1.3MPaG to 0.05MPaG; through oil washing and degassing, the oil content and dissolved organic matter content in the waste lye are reduced to about 4000mg / l;

[0047] (2) the storage tank is left standing: the spent lye after preliminary ...

Embodiment 3

[0052] A stream of waste lye discharged from the bottom of the MTO alkali washing tower, wherein: COD is 8000mg / l, Na 2 CO 3 The concentration is 7.6 wt%, the NaOH concentration is 1.6 wt%, the free oil is 250 mg / l, the methanol concentration is 0.03 mol%, and the dimethyl ether concentration is 0.01 mol%.

[0053] use figure 1 The processing flow chart shown, the processing steps are as follows:

[0054] (1) Oil washing and degassing: Utilizing the difference in solubility, washing oil is used to wash MTO waste lye, and by standing and stratifying, the washing oil and waste lye are separated, and the oil entrained in waste lye is initially removed Carry out decompression treatment to the waste lye after oil washing to reduce its pressure from 1.4MPaG to 0.1MPaG; through oil washing and degassing, the oil content and dissolved organic content in the waste lye are reduced to about 5000mg / l;

[0055] (2) The storage tank is left standing: the spent lye after preliminary oil r...

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Abstract

The invention provides a low-cost and zero-discharge treatment process for MTO alkaline washing waste alkali liquor. The treatment process comprises the following steps: (1) oil washing and degassing: washing the MTO waste alkali liquor by adopting washing oil, preliminarily removing oil entrained in the waste alkali liquor, and then performing reduced pressure treatment; (2) standing in a storage tank: keeping and standing the waste alkali liquor subjected to preliminary oil removal and reduced pressure treatment in the storage tank, and further removing floating oil after the oil and water are demixed; (3) removal of carbonate: adding a carbonate precipitant into the waste alkali liquor subjected to standing oil removal for precipitation reaction, and removing precipitates in the waste alkali liquor after standing demixing; (4) regeneration of alkali liquor: adding sodium hydroxide into the waste alkali liquor from which the carbonate is removed, and regenerating the alkali liquor. According to the treatment process, the sodium hydroxide can be recycled, zero discharge of waste alkali liquor treatment is realized, the using amount of the alkali liquor is greatly reduced, and the environmental protection pressure is reduced.

Description

technical field [0001] The invention relates to the field of petrochemical wastewater treatment, and more specifically, relates to a zero-discharge treatment process of low-cost MTO alkaline washing waste lye. Background technique [0002] MTO plant product gas contains CO 2 and other acid gases, the process requires the CO in the product gas 2 Remove to 10 -6 (VOL) or less. At present, it is widely used to set up an alkali washing tower to remove CO by washing the product gas with NaOH solution. 2 . During the scrubbing process, the acid gas reacts with NaOH to remove it, and waste lye is generated at the same time. [0003] Unlike the waste lye produced by ethylene plants, MTO waste lye does not contain sulfur, but contains organic oxides such as dimethyl ether and methanol. The existence of organic matter will lead to high COD of spent caustic soda, and in the subsequent treatment process, it is difficult to degrade such organic oxides by traditional biochemical sew...

Claims

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Application Information

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IPC IPC(8): C02F9/04B01D53/96
CPCB01D53/96B01D2251/304B01D2251/604C02F1/40C02F1/52C02F1/58C02F9/00C02F2301/08
Inventor 段波潘珂陈海王振维赵百仁雷正香
Owner SINOPEC ENG