Process for removing oil substances in coking wastewater based on electron beam irradiation principle

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a process for removing oil substances in coking wastewater based on an electron beam irradiation principle, which comprises the following steps: adding persulfate into the coking wastewater and carrying out electron beam irradiation treatment at the same time; and carrying out coagulation treatment and flocculation treatment on the coking wastewater subjected to electron beam irradiation treatment. Aiming at the problems that oil substances in the coking wastewater are difficult to remove and the treatment cost is high, the invention provides a persulfate synergistic electron beam irradiation-coagulation and flocculent precipitation combined process, so that the removal of the oil substances in the coking wastewater is remarkably enhanced. The combined process is easy to operate, has the advantages of being good in treatment effect, short in treatment time and low in treatment cost for the oil substances in the coking wastewater, and shows wide application prospects in the field of treatment of the oil substances in the coking wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation. Background Art

[0002] Coal chemical industry, as an important part of my country's chemical industry, is an industrial project that processes raw coal to produce chemical energy products. In the process of coal chemical industry, there will be emissions of waste gas, wastewater and solid waste pollution sources. Coal chemical wastewater can be divided into coking wastewater, liquefied wastewater and gasification wastewater. Among them, coking wastewater refers to the wastewater with complex components produced in the process of heating coal in isolation from air and producing coal products. The wastewater from this source contains a variety of harmful and difficult-to-degrade organic matter. If it is not effectively treated and directly discharged, it will seriously damage the ecological environment.

[0003] At present, the existing technology for removing organic matter from coking wastewater mainly targets the organic pollutants dissolved in coking wastewater. For hydrophobic oil substances, the current treatment processes mainly include cyclone filtration technology, air flotation technology, fiber coalescence separation technology and membrane separation technology. Among them, cyclone filtration technology is a technology that combines filtration with centrifugal separation to achieve the separation of oil, water and sand in wastewater; air flotation technology is a technology that introduces air into the treated wastewater to generate a large number of tiny bubbles, which promotes the adsorption of oil substances and bubbles, thereby achieving rapid separation and removal of oil substances; fiber coalescence separation technology is a technology that coalesces small oil droplets into large oil droplets, thereby enhancing sedimentation separation. However, the above three technologies can only remove part of the oil substances, and the removal effect is not good. Membrane separation technology achieves oil-water separation through pore size interception. Although the removal effect is good, the membrane is easy to clog, resulting in an increase in the frequency of membrane backwashing, which reduces the service life of the membrane and increases the treatment cost. Therefore, how to economically and efficiently treat oil substances in coking wastewater is still a problem that needs to be solved urgently. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of poor treatment effect and high treatment cost of the existing treatment process for oil substances in coking wastewater, thereby providing a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation to solve the above problems.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A process for removing oily substances from coking wastewater based on the principle of electron beam irradiation comprises: adding persulfate to the coking wastewater and simultaneously performing electron beam irradiation treatment; and performing coagulation treatment and flocculation treatment on the coking wastewater after the electron beam irradiation treatment.

[0007] Preferably, the concentration of oil substances in the coking wastewater is ≤300 mg / L.

[0008] Preferably, the persulfate includes peroxymonosulfate and / or peroxydisulfate, preferably peroxymonosulfate. When peroxydisulfate is used, the dosage is much greater than that of peroxymonosulfate.

[0009] Preferably, when the persulfate is peroxymonosulfate, the dosage of peroxymonosulfate is ≥ 0.2 mM, preferably 0.2-5 mM;

[0010] And / or, the dose of the electron beam irradiation treatment is ≥1 kGy, preferably 1-10 kGy.

[0011] Preferably, when the dosage of the peroxymonosulfate is 0.2-1 mM, the dosage of the electron beam irradiation treatment is 1-2 kGy;

[0012] And / or, when the dosage of the peroxymonosulfate is 1-5 mM, the dosage of the electron beam irradiation treatment is 5-10 kGy.

[0013] Preferably, the coagulant used in the coagulation treatment includes at least one of polyaluminium ferric chloride and polyferric sulfate, preferably polyaluminium ferric chloride.

[0014] Preferably, the flocculant used in the flocculation treatment includes polyacrylamide.

[0015] Preferably, the duration of the coagulation treatment is 5-30 min;

[0016] And / or, the duration of the flocculation treatment is 5-30 min.

[0017] Preferably, the mass concentration of the coagulant in the coagulation treatment is 1-3‰.

[0018] Preferably, the mass concentration of the flocculant in the flocculation treatment is 0.5-1‰.

[0019] In the present invention, the electron beam irradiation is generated by a high energy electron accelerator, and the energy thereof is between 0.5-2 MeV.

[0020] The technical solution of the present invention has the following advantages:

[0021] 1. A process for removing oily substances from coking wastewater based on the principle of electron beam irradiation, comprising: adding persulfate to the coking wastewater while performing electron beam irradiation treatment; and performing coagulation and flocculation treatment on the coking wastewater after electron beam irradiation treatment. In view of the problem that oily substances in coking wastewater are difficult to remove and the treatment cost is high, the present invention proposes a combined process of persulfate synergistic electron beam irradiation-coagulation and flocculation precipitation, thereby significantly enhancing the removal of oily substances in coking wastewater. The combined process is simple to operate, and has the advantages of good treatment effect, short treatment time and low treatment cost for oily substances in coking wastewater, showing broad application prospects in the field of treatment of oily substances in coking wastewater. Specifically, persulfate can acidify coking wastewater, thereby hydrolyzing and removing some oily substances; at the same time, persulfate will produce sulfate radicals under the action of electron beam irradiation, and the sulfuric acid radicals will further react with peroxymonosulfate to produce SO 5 Free radicals, SO 5 Free radicals can be further converted into singlet oxygen, which has higher selectivity and can further strengthen the oxidation of oil substances. At the same time, combined with the active species produced by electron beam irradiation itself, the oxidation of oil substances in coking wastewater is strengthened, thereby changing the hydrophilic and hydrophobic balance of oil substances, making the entire oil molecule more hydrophilic. As a result, the oxidized oil substances can be better polymerized into macromolecules by coagulants and flocculants, and then removed by precipitation, achieving the aggregation and removal of oil substances.

[0022] 2. In the process of removing oily substances from coking wastewater based on the electron beam irradiation principle of the present invention, when the persulfate is peroxymonosulfate, the dosage of peroxymonosulfate is 0.2-5mM, and the concentration of peroxymonosulfate is too high, so that the pH of the coking wastewater is strongly acidic (pH≤3), and acidic hydrolysis can be achieved at this time, and the acidity is also conducive to changing the hydrophilic and hydrophobic properties of oily substances. Under the condition of strongly acidic pH, the electron beam irradiation activated water mainly produces hydrogen free radicals. The hydrogen free radicals can react with the oily substances to undergo hydrogenation, thereby changing the hydrophilic and hydrophobic balance of the oily substances, making the entire oil molecule more hydrophilic.

[0023] 3. In the process of removing oil substances from coking wastewater based on the principle of electron beam irradiation of the present invention, polyaluminium ferric chloride (PAFC) is first used for coagulation, and then polyacrylamide (PAM) is used for flocculation. The monopersulfate remaining in the effluent after electron beam irradiation produces active species in the flocculation unit with the help of PAFC, further enhancing the removal effect of oil substances in the water. Among them, the material selection of coagulant and flocculant in this process belongs to a specific combination. If PAFC is replaced with polyferric sulfate (PFS), the treatment effect of oil substances in coking wastewater will be poor, and the acidity of the effluent will be significantly enhanced, requiring further alkali adjustment, which will significantly increase the treatment cost. Finally, adding PAM can polymerize the oil substances in the water and the organic matter formed in the above treatment into macromolecules, which are then removed by precipitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The present invention is a process flow chart for removing oil substances from coking wastewater based on the principle of electron beam irradiation. DETAILED DESCRIPTION

[0026] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0027] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0028] In the following embodiments and comparative examples, the oil concentration test method is: "SY / T 0530-2011 Determination of Oil Content in Oilfield Produced Water - Spectrophotometric Method".

[0029] Example 1

[0030] This embodiment provides a process for removing oil substances from coking wastewater based on the principle of electron beam irradiation. The process flow is as follows: Figure 1As shown, coking wastewater from a coking plant is obtained, wherein the COD of the coking wastewater is 1920 mg / L, the concentration of oil substances is 270 mg / L, and the pH of the wastewater is 7.8. The treatment steps of the above wastewater in this embodiment are as follows:

[0031] 1) adding peroxymonosulfate to the above coking wastewater and simultaneously performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.84 mM and the electron beam irradiation dose is 1 kGy;

[0032] 2) PAFC was added to the coking wastewater after electron beam irradiation treatment. The mass concentration of PAFC in the wastewater was 2‰. After stirring for 30 minutes, 1‰ PAM was added. After precipitation for 30 minutes, the concentration of oil substances in the effluent was measured to be 14 mg / L, and the effluent pH was 7.1.

[0033] Example 2

[0034] This embodiment provides a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this embodiment are as follows:

[0035] 1) adding peroxymonosulfate to the coking wastewater and performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.84 mM and the electron beam irradiation dose is 2 kGy;

[0036] 2) PAFC was added to the coking wastewater after electron beam irradiation treatment. The mass concentration of PAFC in the wastewater was 2‰. After stirring for 30 minutes, 1‰ PAM was added. After precipitation for 30 minutes, the concentration of oil substances in the effluent was measured to be 6 mg / L, and the effluent pH was 6.9.

[0037] Example 3

[0038] This embodiment provides a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this embodiment are as follows:

[0039] 1) adding peroxymonosulfate to the coking wastewater and performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.84 mM and the electron beam irradiation dose is 2 kGy;

[0040] 2) PAFC was added to the coking wastewater after electron beam irradiation with a mass concentration of 3‰ in the wastewater. After stirring for 30 minutes, 1‰ PAM was added. After precipitation for 30 minutes, the concentration of oil substances in the effluent was measured to be 2 mg / L, and the effluent pH was 6.4.

[0041] Example 4

[0042] This embodiment provides a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this embodiment are as follows:

[0043] 1) adding peroxymonosulfate to the coking wastewater and performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.4 mM and the electron beam irradiation dose is 2 kGy;

[0044] 2) PAFC was added to the coking wastewater after electron beam irradiation treatment. The mass concentration of PAFC in the wastewater was 1‰. After stirring for 30 minutes, 1‰ PAM was added. After precipitation for 5 minutes, the concentration of oil substances in the water was measured to be 53 mg / L, and the effluent pH was 7.3.

[0045] Example 5

[0046] This embodiment provides a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this embodiment are as follows:

[0047] 1) adding peroxymonosulfate to the coking wastewater and performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 5 mM and the electron beam irradiation dose is 10 kGy;

[0048] 2) PAFC was added to the coking wastewater after electron beam irradiation treatment. The mass concentration of PAFC in the wastewater was 3‰. After stirring for 5 minutes, 0.5‰ PAM was added. After precipitation for 30 minutes, the concentration of oil substances in the water was measured to be 0 mg / L, and the effluent pH was 6.3.

[0049] Example 6

[0050] This embodiment provides a process for removing oil substances in coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this embodiment are as follows:

[0051] 1) adding peroxymonosulfate to the coking wastewater and performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.84 mM and the electron beam irradiation dose is 2 kGy;

[0052] 2) PFS was added to the coking wastewater after electron beam irradiation treatment. The mass concentration of PFS in the wastewater was 2‰. After stirring for 30 minutes, 1‰ PAM was added. After precipitation for 30 minutes, the concentration of oil substances in the effluent was measured to be 47 mg / L, and the effluent pH was 3.7.

[0053] Comparative Example 1

[0054] This comparative example provides a process for removing oily substances from coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this comparative example are as follows:

[0055] While adding peroxymonosulfate to the coking wastewater, electron beam irradiation treatment was performed, wherein the dosage of peroxymonosulfate was 0.84 mM and the electron beam irradiation dose was 2 kGy. The concentration of oil substances in the water was measured to be 137 mg / L and the pH of the effluent was 7.6.

[0056] Comparative Example 2

[0057] This comparative example provides a process for removing oily substances from coking wastewater. The coking wastewater used is the same as that in Example 1. The treatment steps of the coking wastewater in this comparative example are as follows:

[0058] 1) adding peroxymonosulfate to the coking wastewater without electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.84 mM and the electron beam irradiation dose is 0 kGy;

[0059] 2) Adding polyaluminium ferric chloride to the coking wastewater treated in step 1), the mass concentration of polyaluminium ferric chloride in the wastewater is 2‰, stirring for 30 minutes, adding 1‰ PAM, and after precipitation for 30 minutes, the concentration of oil substances in the water is measured to be 81 mg / L.

[0060] Comparative Example 3

[0061] This comparative example provides a process for removing oily substances from coking wastewater based on the principle of electron beam irradiation. The coking wastewater used is the same as that in Example 1. The steps for treating the coking wastewater in this comparative example are as follows:

[0062] 1) adding peroxymonosulfate to the coking wastewater and reacting for 30 minutes, and then performing electron beam irradiation treatment, wherein the dosage of peroxymonosulfate is 0.84 mM and the electron beam irradiation dose is 2 kGy;

[0063] 2) PAFC was added to the coking wastewater after electron beam irradiation treatment. The mass concentration of PAFC in the wastewater was 2‰. After stirring for 30 minutes, 1‰ PAM was added. After precipitation for 30 minutes, the concentration of oil substances in the water was measured to be 67 mg / L.

[0064] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A process for removing oil from coking wastewater based on the principle of electron beam irradiation, characterized in that: include: Adding persulfate to coking wastewater and simultaneously subjecting it to electron beam irradiation treatment; The coking wastewater after electron beam irradiation treatment is subjected to coagulation and flocculation treatment.

2. The process according to claim 1, characterized in that The concentration of oil substances in the coking wastewater is ≤300 mg / L.

3. The process according to claim 1 or 2, characterized in that The persulfate includes peroxymonosulfate and / or peroxydisulfate, preferably peroxymonosulfate.

4. The process according to any one of claims 1 to 3, characterized in that When the persulfate is peroxymonosulfate, the dosage of peroxymonosulfate is ≥ 0.2 mM, preferably 0.2-5 mM; And / or, the dose of the electron beam irradiation treatment is ≥1 kGy, preferably 1-10 kGy.

5. The process according to claim 4, characterized in that When the dosage of the peroxymonosulfate is 0.2-1 mM, the dosage of the electron beam irradiation treatment is 1-2 kGy; And / or, when the dosage of the peroxymonosulfate is 1-5 mM, the dosage of the electron beam irradiation treatment is 5-10 kGy.

6. The process according to any one of claims 1 to 5, characterized in that The coagulant used in the coagulation treatment includes at least one of polyaluminium ferric chloride and polyferric sulfate, preferably polyaluminium ferric chloride.

7. The process according to any one of claims 1 to 6, characterized in that The flocculant used in the flocculation treatment includes polyacrylamide.

8. The process according to any one of claims 1 to 7, characterized in that The duration of the coagulation treatment is 5-30 minutes; And / or, the duration of the flocculation treatment is 5-30 min.

9. The process according to any one of claims 1 to 8, characterized in that The mass concentration of the coagulant in the coagulation treatment is 1-3‰.

10. The process according to any one of claims 1 to 9, characterized in that The mass concentration of the flocculant in the flocculation treatment is 0.5-1‰.

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