CN105174552A - Oil removal treatment method for high-concentration sewage in coal chemical industry - Google Patents

Abstract

The invention relates to a method for degreasing treatment of high-concentration sewage in the coal chemical industry; the specific steps are as follows: firstly, the high-concentration sewage in the coal chemical industry enters the deoiling and demulsification unit and adds a demulsifier and a coagulant aid to make the oily substances in the waste water Demulsification achieves the removal effect; then the wastewater after oil removal and demulsification enters the adsorption unit, and the solid suspended particles and oily substances in the wastewater are further removed by the adsorbent. The removal rates of oily substances and solid suspended particles in waste water through the invention are as high as 97% and 95% respectively, and the COD removal rate is as high as 40%. The invention has the characteristics of simple treatment process, good effect, low treatment cost and the like, and has broad application prospects.

Description

A method for degreasing treatment of high-concentration sewage in coal chemical industry

technical field

The invention relates to a water treatment method, in particular to an oil removal treatment method suitable for high-concentration sewage in coal chemical industry.

Background technique

The development of coal chemical industry is my country's energy demand, but with the development of modern coal chemical industry, its "water pollution" and "water shortage" are becoming more and more serious, which seriously threatens the sustainable development of enterprises, and it is urgent to realize "near-zero emissions". However, the high-concentration sewage of coal chemical industry contains a large amount of oily substances and solid suspended particles in the water, which leads to blockage of heat exchangers during the recovery process of phenolic ammonia, reduces the stability of the phenolic ammonia recovery system, and inhibits microbial metabolism in the subsequent biochemical process. Reduce biochemical efficiency. Therefore, in order to improve the reuse rate of reclaimed water, the key is to remove oil and turbidity. At present, there are many methods for treating oily wastewater, such as chemical method (salting out method, coagulation method), electrochemical method; membrane separation method, air flotation method; biological method, etc. These methods have their own disadvantages: the equipment occupies a large area, high investment, large dosage of chemicals, and complicated pretreatment. Gravity method, air flotation method, membrane technology, etc. are widely used in domestic and foreign coal chemical wastewater treatment technology projects, which do not address the characteristics of large water volume, oil and suspended solids content in high-concentration coal chemical wastewater, resulting in overall degreasing , Dust removal cost is high and efficiency is low. At present, more demulsifiers are used to remove oil, but the existing conventional demulsifiers have poor applicability, low efficiency, and secondary pollution because they do not have the characteristics of oil and solid suspended particles in high-concentration coal chemical sewage water. , Dosing large amount and other issues.

Chinese patent application CN104826578A discloses a fly ash modified adsorbent and a method for preparing and treating oily sewage. The method uses specific component modification, specific process parameters and operating steps to make the final adsorbent The treatment of oily sewage has a certain effect when used in low-concentration oil-content wastewater, but if it is used to deal with complex and stable coal chemical high-concentration sewage, it shows shortcomings such as large dosage and substandard treatment effect. Patent CN103435132B discloses a method and device for treating oily wastewater with activated carbon fiber and its regeneration method and device. The electrochemical treatment of oily wastewater with activated carbon fiber and its in-situ regeneration technology for oil removal are cumbersome and difficult to realize industrial application.

Contents of the invention

The object of the present invention is to provide an oil removal treatment method for high-concentration sewage in coal chemical industry in order to improve the deficiencies of the prior art.

The technical solution of the present invention is: a method for degreasing treatment of high-concentration sewage in coal chemical industry, which is characterized in that the process flow is as follows: high-concentration sewage inflow→oil removal and demulsification unit→adsorption unit→filter tank→water outlet; its specific steps as follows:

① Oil removal and demulsification unit: Sewage enters the oil removal and demulsification treatment unit, and demulsifiers and additives are added to the degreasing tank to control the temperature reaction, thereby removing oily substances in the water. Wherein said demulsifier is a polyether demulsifier or a mixed demulsifier of sulfuric acid and polyether demulsifier;

②Adsorption unit: The effluent from the oil removal and demulsification unit enters the adsorption unit, and is treated by adding an adsorbent; the solid suspended particles in the water are removed and the oil is further removed.

③Filter pool: filter the effluent from the adsorption unit to retain the adsorbent.

Preferably, the polyether demulsifier described in the above step ① is propylene glycol block ether, isomeric decanth or lauryl polyethers, etc.

When the above-mentioned demulsifier is a polyether demulsifier, the volume ratio of the added mass of the demulsifier to the sewage is 200-500 mg/L.

When the above-mentioned demulsifier is a mixed demulsifier, the volume ratio of the added mass of sulfuric acid in the demulsifier to the sewage is 8-12g/L. The mass ratio of sulfuric acid and polyether demulsifier in the mixed demulsifier is 2-5:1.

Preferably, the controlled temperature in the oil removal and demulsification unit is 25-40° C.; the reaction time is 0.5-5 hours.

Preferably, the auxiliary agent described in step ① is one or both of anionic polyacrylamine, cationic polyacrylamine or diatomite; the volume ratio of the additive mass to sewage is 5-10 mg/L.

The adsorbent described in the preferred step ② is a mixture of activated carbon and fly ash; the mass ratio of activated carbon to fly ash is 1: (1～4); the volume ratio of activated carbon dosing quality to sewage is 2.5～7.5g/ L. The treatment time after adding the adsorbent is generally 3 to 5 hours.

Beneficial effect:

(1) The method for degreasing treatment of high-concentration coal chemical sewage according to the present invention has the advantages of less demulsifier consumption, good effect and fast treatment speed in the overall process.

(2) After the process of the present invention, the oily substances and solid suspended particles in the water can be aggregated, and the removal rate can reach more than 97% and 95% respectively, and the removal rate of COD can reach more than 40%.

(3) The demulsifier added in the present invention is an organic compound of sulfuric acid and polyether demulsifier, which effectively reduces the dosage of demulsifier in the degreasing process, significantly improves the degreasing efficiency, and has no secondary pollution And other issues.

Detailed ways

The technical solutions of the present invention will be further described below through specific implementation examples. In the following examples, the dosing quality of demulsifiers, additives and adsorbents is based on the volume of high-concentration coal chemical sewage to be treated in step ①.

Example 1

A method for degreasing treatment of high-concentration coal chemical sewage, comprising the following steps:

① Sewage enters the degreasing and demulsifying treatment unit, and the demulsifying agent propylene glycol segmented ether is added to the degreasing pool. The dosage is 200mg/L, the temperature is 25°C, and the reaction time is 1h. The additive added is anionic polyacrylamine, and the dosage is 5mg/L.

②The effluent from the oil removal and demulsification unit enters the adsorption unit to remove solid suspended particles in the water and further remove oil through the adsorbent. The adsorbent is a mixture of activated carbon and fly ash. The mixing ratio of activated carbon and fly ash is 1:1. The dosage of fly ash is 2.5g/L and 2.5g/L respectively; the adsorption time is 3 hours.

③Filter the effluent from the adsorption unit to retain the adsorbent.

Table 1 degreasing effect

Example 2

A method for degreasing treatment of high-concentration coal chemical sewage, comprising the following steps:

① The sewage enters the oil removal and demulsification treatment unit, and the demulsifier isomeric decanol polyether is added to the oil removal tank, the dosage is 400mg/L, the temperature is 35°C, and the reaction time is 2.5h. The additive added is cationic polyacrylamine, and the dosage is 7.5mg/L.

②The effluent from the oil removal and demulsification unit enters the adsorption unit to remove solid suspended particles in the water and further remove oil. The adsorbent is a mixture of activated carbon and fly ash, and the mixing ratio of activated carbon and fly ash is 1:2.5. The dosages of activated carbon and fly ash are 3g/L and 7.5g/L respectively; the adsorption time is 4 hours.

③Filter the effluent from the adsorption unit to retain the adsorbent.

Table 2 degreasing effect

Example 3

A method for degreasing treatment of high-concentration coal chemical sewage, comprising the following steps:

① After homogeneous adjustment, the sewage enters the degreasing and demulsifying treatment unit, and the mixture of demulsifying agent sulfuric acid and lauryl polyether is added to the degreasing tank, the mixing ratio is 3:1, and the dosage of sulfuric acid is 9g /L, the temperature is 40°C, and the reaction time is 5h. The additive added is diatomaceous earth, and the dosage is 10mg/L.

②The effluent from the oil removal and demulsification unit enters the adsorption unit to remove solid suspended particles in the water and further remove oil. The adsorbent is a mixture of activated carbon and fly ash, and the mixing ratio of activated carbon and fly ash is 1:4. The dosages of activated carbon and fly ash are 5g/L and 20g/L respectively; the adsorption time is 3 hours.

③Filter the effluent from the adsorption unit to retain the adsorbent.

Table 3 degreasing effect

Example 4

A method for degreasing treatment of high-concentration coal chemical sewage, comprising the following steps:

① Sewage enters the degreasing and demulsifying treatment unit, and a mixture of demulsifying agent sulfuric acid and tetradecyl polyether is added to the degreasing tank, the mixing ratio is 4.5:1, the dosage of sulfuric acid is 11g/L, and the temperature is 40°C, the reaction time is 3h. The additive added is cationic polyacrylamide, and the dosage is 10mg/L.

②The effluent from the oil removal and demulsification unit enters the adsorption unit to remove solid suspended particles in the water and further remove oil. The adsorbent is a mixture of activated carbon and fly ash, and the mixing ratio of activated carbon and fly ash is 1:3. The dosages of activated carbon and fly ash are 7.5g/L and 22.5g/L respectively; the adsorption time is 4.5 hours.

③Filter the effluent from the adsorption unit to retain the adsorbent.

Table 3 degreasing effect

Claims (8)

1. an oil removal treatment method for Coal Chemical Industry height strong sewage, is characterized in that technical process is as follows: high strong sewage water inlet → oil removing breakdown of emulsion unit → absorbing unit → filtering basin → water outlet; Its concrete steps are as follows:

1. oil removing breakdown of emulsion unit: sewage enters oil removing breakdown of emulsion processing unit, adds emulsion splitter and auxiliary agent in grease removal tank, control temperature reacts; Wherein said emulsion splitter is the mixing emulsion splitter of polyether demulsification agent or sulfuric acid and polyether demulsification agent;

2. absorbing unit: the water outlet of oil removing breakdown of emulsion unit enters into absorbing unit, adds sorbent material and processes;

3. filtering basin: absorbing unit water outlet is filtered, retains sorbent material.

2. oil removal treatment method according to claim 1, is characterized in that the polyether demulsification agent described in step is 1. propylene glycol block ether, isomery ten alcohol polyethers or ten tetracosanol polyethers.

3. oil removal treatment method according to claim 1, when it is characterized in that the emulsion splitter described in step is 1. polyether demulsification agent, the volume ratio adding quality and sewage of emulsion splitter is 200 ~ 500mg/L.

4. oil removal treatment method according to claim 1, is characterized in that the mass ratio of sulfuric acid and polyether demulsification agent in the mixing emulsion splitter described in step is 1. 2 ~ 5:1.

5. oil removal treatment method according to claim 1, it is characterized in that step 1. in emulsion splitter for mixing emulsion splitter time, in emulsion splitter, the volume ratio adding quality and sewage of sulfuric acid is 8 ~ 12g/L.

6. oil removal treatment method according to claim 1, is characterized in that the temperature described in step is 1. 25 ~ 40 DEG C; Reaction times is 0.5 ~ 5h.

7. oil removal treatment method according to claim 1, it is characterized in that the auxiliary agent described in step be 1. anion pp amine, cation polypropylene amine or diatomaceous one or both; The volume ratio adding quality and sewage of auxiliary agent is 5 ~ 10mg/L.

8. oil removal treatment method according to claim 1, is characterized in that the sorbent material described in step is 2. the mixture of gac and flyash; The mass ratio of gac and flyash is 1:(1 ~ 4); The volume ratio that gac adds quality and sewage is 2.5 ~ 7.5g/L.