A pretreatment method for waste mixed with aqueous liquid and flammable liquid

Abstract

The present invention discloses a pretreatment method for waste mixed with aqueous liquid and flammable liquid, comprising the following steps: S1: According to the standard test method of ASTM D5058-90 waste water compatibility screening analysis, perform the compatibility test of aqueous liquid, flammable liquid waste and amphiphilic adsorption carrier in advance; S2: Put the flammable liquid waste and amphiphilic adsorption carrier into the pretreatment center for pretreatment; S3: According to the feeding amount in step S2, add the same amount of aqueous liquid waste and stir well; S4: Supplement the amphiphilic adsorption carrier, take samples after sufficient stirring, and test according to the standard test method of ASTM D4982 waste potential flammability screening analysis until the samples are not flammable, then stop adding the amphiphilic adsorption carrier; S5: Convey the formed waste to the incineration system through a conveying device. The method adopted by the present invention can fundamentally change the current situation of incineration disposal of flammable liquid hazardous waste with high solid content adsorbed, and has good popularization value and market prospect.

Description

Technical Field

[0001] The present invention relates to a treatment process for hazardous waste, and particularly to a pretreatment method for waste mixtures of aqueous liquid and flammable liquid. Background Art

[0002] With the continuous development of modern industrialization, the amount of waste generated in factory production, especially hazardous waste, is increasing day by day. According to the national hazardous waste list, there are a total of 50 categories and more than 3,000 types of hazardous waste, and most of them are suitable for reduction treatment by incineration. The prerequisite for stable and safe incineration of materials in the furnace is: ① relatively consistent incineration rate; ② relatively unified lower calorific value; ③ no violent deflagration reaction; the physical and chemical properties of hazardous waste fluctuate within a large range, such as the mass fluctuation range is from a few milligrams to about 15 kg; the moisture content fluctuation range is from 0% to 70%; the calorific value fluctuation range is from 600 kcal to 1,000 kcal. And the physical forms are diverse, such as solid, liquid, paste, powder, etc. When mixed with incompatible substances, violent reactions often occur, resulting in harmful gas generation or deflagration accidents.

[0003] At present, the method of simply mixing and matching materials and directly sending them into the incinerator for incineration is adopted. No targeted pretreatment is carried out before entering the incinerator, resulting in unstable incineration effect, low burnout rate, difficult tail gas treatment, difficult emission compliance, and high content of unburned organic matter in the ash residue and other environmental pollution problems. Among them, flammable liquid hazardous waste with low solid content and good fluidity can be directly pumped for disposal after filtration, while flammable liquid hazardous waste with high solid content and poor fluidity is lifted into the rotary kiln for incineration in small buckets, but it is easy to cause flash explosion at the feeding port, not only with very high safety and pretreatment costs, but also with low disposal efficiency, and cannot meet the disposal requirements of flammable liquid hazardous waste.

[0004] The main purpose of the present invention is to use innovative thinking to reasonably pretreat flammable liquid hazardous waste and aqueous hazardous waste at a relatively low cost, so that they can be separately incinerated and destroyed in the rotary kiln. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that at present, flammable liquid hazardous waste with high solid content and poor fluidity is lifted into the rotary kiln for incineration in small buckets, which is easy to cause flash explosion at the feeding port, not only with very high safety and pretreatment costs, but also with low disposal efficiency, and cannot meet the disposal requirements of flammable liquid hazardous waste.

[0006] To solve the above technical problems, the present invention provides a pretreatment method for waste mixtures of aqueous liquid and flammable liquid, including the following steps:

[0007] S1: According to the standard test method of ASTM D5058-90 Waste-Water Compatibility Screening Analysis, pre-conduct the compatibility test of aqueous liquid, flammable liquid waste, and amphiphilic adsorption carrier;

[0008] S2: Put the flammable liquid waste and amphiphilic adsorption carrier into the pretreatment center for pretreatment;

[0009] S3: According to the feeding amount in step S2, add the same amount of aqueous liquid waste and stir well for mixing;

[0010] S4: Supplement the adsorption carrier, take samples after sufficient stirring, and test according to the standard test method of ASTM D4982 Waste Potential Flammability Screening Analysis until the samples are non-flammable, then stop adding the adsorption carrier;

[0011] S5: Convey the formed waste to the incineration system through the conveying device.

[0012] According to the embodiment of the present application, the amphiphilic adsorption carrier uses wood chips.

[0013] According to the embodiment of the present application, the liquid flammable waste includes waste engine oil, waste ink, waste paint, waste glue, liquid high-boiling substances, liquid distillation residues. The main components of the liquid flammable waste cannot carry carboxyl functional groups and are HW02 Pharmaceutical Waste, HW06 Waste Organic Solvents and Wastes Containing Organic Solvents, HW08 Waste Mineral Oil and Wastes Containing Mineral Oil, HW11 Distillation (Evaporation) Residues, HW12 Dye and Coating Wastes, HW13 Organic Resin Wastes, and HW49 Other Wastes in the National Hazardous Waste List; the aqueous hazardous waste includes waste emulsion, waste concentrate, waste paint water, waste developer, and the aqueous liquid hazardous waste is HW09 Waste Oil / Water, Hydrocarbon / Water Mixture or Emulsion, W12 Dye and Coating Wastes, HW16 Photographic Materials Wastes, and HW49 Other Wastes in the National Hazardous Waste List.

[0014] According to the embodiment of the present application, the pretreatment center is provided with a deodorizing slightly negative pressure system and a waste liquid stirring tank, and the flammable liquid waste, amphiphilic adsorption carrier, and aqueous liquid waste are all put into the waste liquid stirring tank for treatment.

[0015] According to the embodiment of the present application, the compatibility test in step S1 includes: respectively take 100 ml of flammable liquid waste, 20 g of wood chips, and 100 ml of aqueous liquid hazardous waste and mix them, and observe whether there are temperature changes, smoking, and foaming phenomena according to the standard test method of ASTM D5058-90 Waste-Water Compatibility Screening Analysis.

[0016] According to an embodiment of the present application, in step S2, the pretreatment is to add the flammable liquid waste and wood chips to the pretreatment center in a weight ratio of (2 - 3):1, start stirring, and make the wood chips fully absorb the flammable liquid waste until no flowing liquid is seen.

[0017] According to an embodiment of the present application, step S3 further includes adding an amphiphilic adsorption carrier before sampling and fully stirring and soaking for 10 - 20 minutes.

[0018] According to an embodiment of the present application, step S5 further includes: the mixture of the flammable liquid waste, amphiphilic adsorption carrier, and aqueous liquid waste after standing is suctioned and separated by a diaphragm pump to remove the upper liquid, and the waste liquid is stored in a storage tank and pumped into the incineration system by a feed pump for incineration.

[0019] According to an embodiment of the present application, the conveying device includes a rotary forklift.

[0020] According to an embodiment of the present application, the incineration system includes a rotary kiln.

[0021] The beneficial effects of the technical solution of the present invention compared with the prior art are as follows:

[0022] 1. According to the amphiphilic property of wood chips, that is, they can absorb both oil and water, the present invention selects an oil-based flammable liquid and an aqueous liquid that are compatible with wood chips, converts them from a flammable liquid state to a combustible / incombustible solid waste, and achieves the purpose by using the characteristic of treating waste with waste.

[0023] 2. The present invention selects amphiphilic wood chips as the adsorption carrier. On the one hand, the source is economical and cheap. On the other hand, according to the characteristic of immiscibility of oil and water, the purpose of wrapping flammable hazardous waste with aqueous hazardous waste can be achieved, so that flash explosion will not occur before entering the rotary kiln. When the wood chips enter the rotary kiln, the water evaporates and dries gradually, and then the oil volatilizes and burns. It will not cause very large fluctuations in the CO index and temperature in the rotary kiln due to sudden deflagration, which is beneficial to the stable operation of the working conditions.

[0024] 3. By comparing the cost of wood chips and the subcontracting cost, the pretreatment cost of flammable liquid hazardous waste is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flowchart of a pretreatment method for a mixture of aqueous liquid and flammable liquid waste of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0027] Figure 1The figure generally shows a flowchart of the pretreatment method for the waste mixture of aqueous liquid and flammable liquid of the present invention.

[0028] As can be seen from Figure 1 a pretreatment method for the waste mixture of aqueous liquid and flammable liquid of the present invention mainly pre-treats flammable liquid waste and aqueous liquid waste.

[0029] Liquid flammable waste includes waste oil, waste ink, waste paint, waste glue, liquid high boilers, and liquid distillation residues. Its main components cannot have carboxyl functional groups. The main components of liquid flammable waste can be HW02 pharmaceutical waste, HW06 waste organic solvents and waste containing organic solvents, HW08 waste mineral oil and waste containing mineral oil, HW11 refined (distilled) residues, HW12 dyes, paint waste, HW13 organic resin waste, and HW49 and other wastes in the National Hazardous Waste List.

[0030] Aqueous liquid waste includes waste emulsion, waste concentrate, waste paint water, and waste developer, and may include HW09 waste oil / water, hydrocarbon / water mixture or emulsion, W12 dyes, paint waste, HW16 photographic material waste, and HW49 other wastes in the National Hazardous Waste List.

[0031] The technical problem solved by the present invention is based on the characteristics of liquid hazardous waste. For example, the main components of flammable hazardous waste are mostly solvents such as alkanes, ethers, and alcohols, which have lipophilicity. The main components of inert hazardous waste are wastewater, which has hydrophilicity. Therefore, the present invention specifically selects a kind of wood chips as the adsorption carrier. Since the main component of wood chips is lignin, its structure contains functional groups such as phenolic hydroxyl, alcoholic hydroxyl, carbonyl, and carboxyl, making it amphiphilic and capable of both absorbing oil and water. Through the wood chips as the adsorption carrier and selecting an appropriate doping ratio, it first adsorbs the flammable oily liquid material, and then adsorbs the aqueous liquid material to wrap on the surface of the oily molecules, forming a non-combustible solid material, which then enters the rotary kiln for safe incineration through a grab bucket or a hoist.

[0032] The hazardous waste pretreatment system adopted by the present invention is in a closed state and is equipped with a deodorizing slightly negative pressure system. The deodorizing slightly negative pressure system is provided with adsorption, filtration, and purification devices, so that harmful gases will not overflow, and it can fully prevent the surrounding environment from being polluted.

[0033] It should be noted that for the compatibility of materials, it means that when two or more hazardous wastes are mixed, the following situations should be prevented: generating a large amount of heat or high pressure, generating flames, exploding, generating flammable gases, generating toxic gases, violent polymerization reactions, and the dissolution of toxic substances.

[0034] Specifically, from Figure 1It can be known that a pretreatment method for waste mixtures of aqueous liquids and flammable liquids according to the present invention includes the following steps:

[0035] S1: Conduct a compatibility test of the aqueous liquid, flammable liquid waste, and amphiphilic adsorbent carrier in advance according to the standard test method of ASTM D5058-90 Waste Water Compatibility Screening Analysis;

[0036] S2: Put the flammable liquid waste and the amphiphilic adsorbent carrier into a pretreatment center for pretreatment;

[0037] S3: Add an equal amount of aqueous liquid waste according to the feeding amount in step S2, and stir and mix well;

[0038] S4: Supplement the adsorbent carrier, stir well and then take a sample. Test according to the standard test method of ASTM D4982 Waste Potential Flammability Screening Analysis until the sample is non-flammable, and then stop adding the adsorbent carrier;

[0039] S5: Convey the formed waste to an incineration system through a conveying device.

[0040] Preferably, the amphiphilic adsorbent carrier uses wood chips.

[0041] Furthermore, the pretreatment center is provided with a deodorizing slightly negative pressure system and a waste liquid stirring tank. The flammable liquid waste, amphiphilic adsorbent carrier, and aqueous liquid waste are all put into the waste liquid stirring tank for treatment.

[0042] Furthermore, the compatibility test in step S1 includes: separately mixing 100 ml of flammable liquid waste, 20 g of wood chips, and 100 ml of aqueous liquid hazardous waste, and observing whether there are temperature changes, smoking, and foaming phenomena according to the standard test method of ASTM D5058-90 Waste Water Compatibility Screening Analysis.

[0043] Furthermore, in step S2, the pretreatment is to add the flammable liquid waste and wood chips to the pretreatment center at a weight ratio of (2-3):1, start stirring, and make the wood chips fully absorb the flammable liquid waste until no flowing liquid is seen.

[0044] Step S3 further includes fully stirring and soaking for 10-20 min after adding the amphiphilic adsorbent carrier before sampling.

[0045] Step S5 further includes: separating the upper layer liquid of the mixture of the flammable liquid waste, amphiphilic adsorbent carrier, and aqueous liquid waste after standing by a diaphragm pump, and storing the waste liquid in a storage tank and pumping it into the incineration system for incineration by a feed pump.

[0046] Furthermore, the conveying device includes a rotary forklift.

[0047] Furthermore, the incineration system includes a rotary kiln.

[0048] When formulating liquid waste, the following situations should also be noted:

[0049] 1) Control the content of acidic pollutants. Controlling the content of acidic pollutants can ensure the normal operation of the incineration system and the up-to-standard discharge of tail gas. Halogenated organic compounds not only affect the calorific value of waste, but also affect the content of acidic gases after waste combustion and the operation of the flue gas treatment system. Improper control is also likely to cause the generation of chlorine gas, which is more corrosive. At the same time, during operation, the waste should be analyzed in detail. After pretreatment, the hazardous waste with high halogen content and large quantity should be burned as evenly as possible, and the overall quantity should be controlled.

[0050] 2) Control the content of heavy metals to ensure the normal operation of the incineration system and the up-to-standard discharge of tail gas during incineration. The overall quantity of organic heavy metal substances should be controlled and evenly fed into the furnace for incineration. Due to the toxic characteristics of these wastes, generally, the waste treated in barrels is fed into the furnace for incineration, and the content and frequency can be controlled each time.

[0051] 3) Control the content of phosphorus. Phosphorus in hazardous waste is mainly organic phosphides. P2O5 generated by incineration will cause a large amount of corrosion to metals at 400 - 700 °C. If the content of phosphorus is not controlled well, the service life of the waste heat boiler will be greatly shortened.

[0052] 4) Reduce the unorganized emission of odor substances. For hazardous waste with a strong odor, if it can be directly incinerated, its formulating operation should be reduced. If it cannot be directly incinerated, its volatilization during the formulating process should be strictly controlled.

[0053] A specific embodiment 1 of the present invention is as follows:

[0054] Using the pretreatment method for flammable liquid waste and aqueous liquid waste of the present application, pretreat the flammable distillation residue in a chemical plant. The flammable liquid waste is HW11 refining (distillation) residue in the National Hazardous Waste List, and its main components are ethanol, butanone oxime, and toluene. The aqueous liquid waste is waste developer, which comes from HW16 in the National Hazardous Waste List, and its main components are water, sodium hydroxide, and sodium sulfate.

[0055] The process is as Figure 1 shown, and the specific operations include the following steps:

[0056] In the pretreatment center with a deodorizing slightly negative pressure system, set 2m 3Waste liquid mixing tank, before treatment, do a compatibility test: take 100ml of distillation kettle residual liquid, 20g of sawdust and 100ml of waste developer respectively, and observe according to ASTM D5058-90 standard test method for waste water compatibility screening analysis to see if there is any temperature change, smoke, foaming, etc. If there is no such phenomenon, the next step can be carried out;

[0057] Pour 200kg of distillation still residual liquid and 100kg of sawdust into the waste liquid stirring tank, start stirring, and allow the sawdust to fully absorb the distillation still residual liquid until no fluid liquid is seen. Then add 300kg of waste developer, mix and stir thoroughly, then add 50kg of sawdust to absorb the remaining developer, stir and soak for 10-20 minutes, then let it stand, take a sample, and test it using ASTM D4982 standard test method for screening analysis of potential flammability of waste, the sample is not flammable;

[0058] The upper layer of liquid was separated by suction using a diaphragm pump, and the waste liquid was stored in a storage tank and pumped into the rotary kiln for incineration by a feed pump. The mixture in the mixing tank was then poured into the waste pit using a rotary forklift, and fed into the rotary kiln for incineration by a grab bucket. No flash explosion or tempering was observed at the kiln head after being put into operation. After 30 minutes of observation, no obvious temperature fluctuation was observed at the rotary kiln head and the secondary combustion chamber.

[0059] A specific embodiment 2 of the present invention is as follows:

[0060] The pretreatment method of flammable liquid waste and aqueous liquid waste of the present application is used to pretreat flammable high-boiling materials of a pharmaceutical factory. The flammable liquid waste is HW02 pharmaceutical waste from the national hazardous waste list, and its main components are methanol, acetone, and diethylamine. The aqueous liquid waste is waste emulsion, which is HW09 oil / water, hydrocarbon / water mixture or emulsion from the national hazardous waste list, and its main components are water, a small amount of mineral oil or synthetic ester, and surfactant.

[0061] In the pretreatment center with deodorization micro-negative pressure system, set up 2m 3 Waste liquid mixing tank, before treatment, do a compatibility test: take 100ml high boiling residual liquid, 20g sawdust and 100ml waste emulsion respectively, and observe whether there is temperature change, smoke, foaming and other phenomena according to ASTM D5058-90 standard test method for waste water compatibility screening analysis. If there are no such phenomena, the next step can be carried out;

[0062] Pour 200 kg of high-boiling residue liquid and 100 kg of wood chips into the waste liquid mixing tank, start stirring to allow the wood chips to fully absorb the high-boiling residue liquid until no flowing liquid is seen. Then add 300 kg of waste emulsion, mix and stir well, and then add 50 kg of wood chips to adsorb the remaining emulsion. After stirring and soaking for 10 - 20 min, let it stand, take samples, and test using the standard test method of ASTM D4982 Waste Potential Flammability Screening Analysis. The samples are not flammable;

[0063] Use a diaphragm pump to suction and separate the upper liquid. The waste liquid is stored in a storage tank and pumped into a rotary kiln for incineration by a feed pump. Then use a rotary forklift to pour the treated mixture in the mixing tank into the waste material pit, and feed it into the rotary kiln for incineration by a grab bucket. After feeding, no flash explosion or backfire phenomenon is seen at the kiln head. Observe for 30 min, and no obvious temperature fluctuations are seen at the kiln head and the secondary combustion chamber of the rotary kiln.

[0064] In summary, a pretreatment method for waste mixtures of aqueous liquid and flammable liquid in this application has the following beneficial effects:

[0065] 1. According to the amphiphilic property of wood chips, which can both absorb oil and water, this invention selects an oily flammable liquid and an aqueous liquid that are compatible with wood chips, converting them from a flammable liquid state to a combustible / incombustible solid waste, and achieving the goal by using the characteristic of treating waste with waste.

[0066] 2. This invention selects amphiphilic wood chips as the adsorption carrier. On the one hand, the source is economical and cheap. On the other hand, according to the property of immiscibility between oil and water, the purpose of wrapping flammable hazardous waste with aqueous hazardous waste can be achieved, so that no flash explosion will occur before entering the rotary kiln. As the wood chips in the rotary kiln gradually evaporate and dry the moisture and then volatilize and burn the oiliness, it will not cause very large fluctuations in the CO index and temperature in the rotary kiln due to sudden deflagration, which is beneficial to the stable operation of the working conditions.

[0067] 3. By comparing the cost of wood chips and the subcontracting cost, the pretreatment cost of flammable liquid hazardous waste is low.

[0068] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention accordingly. For those skilled in the art, it should be realized that all equivalent replacements and obvious changes made by using the description and illustration content of the present invention should be included in the protection scope of the present invention.

Claims

1. A pretreatment method for waste mixtures of aqueous liquids and flammable liquids, characterized in that, it includes the following steps: S1: According to the standard test method of ASTM D5058-90 Waste Water Compatibility Screening Analysis, pre-conduct the compatibility test of aqueous liquids, flammable liquid waste, and amphiphilic adsorption carriers; S2: Put the flammable liquid waste and amphiphilic adsorption carriers into the pretreatment center for pretreatment; S3: According to the feeding amount in step S2, add the same amount of aqueous liquid hazardous waste, and stir and mix well; S4: Supplement the adsorption carrier, stir well and then take samples. Test according to the standard test method of ASTM D4982 Waste Potential Flammability Screening Analysis until the samples are not flammable, and then stop adding the adsorption carrier; S5: Convey the formed waste to the incineration system through a conveying device; The compatibility test in step S1 includes: separately mix 100 ml of flammable liquid waste, 20 g of wood chips, and 100 ml of aqueous liquid hazardous waste, and observe whether there are temperature changes, smoking, and foaming phenomena according to the standard test method of ASTM D5058-90 Waste Water Compatibility Screening Analysis; In step S2, the pretreatment is to add the flammable liquid waste and wood chips to the pretreatment center in a weight ratio of (2-3):1, start stirring, and make the wood chips fully absorb the flammable liquid waste until no flowing liquid is seen; In step S4, sample after stirring and soaking for 10-20 min; Step S5 further includes: let the mixture of flammable liquid waste, amphiphilic adsorption carrier, and aqueous liquid hazardous waste stand still, and then use a diaphragm pump to suction and separate the upper layer of liquid. The waste liquid is stored in a storage tank and pumped into the incineration system by a feed pump for incineration.

2. The pretreatment method for waste according to claim 1, characterized in that, the amphiphilic adsorption carrier is wood chips.

3. The pretreatment method for waste according to claim 1, characterized in that, the flammable liquid waste specifically includes waste engine oil, waste ink, waste paint, waste glue, liquid high boilers, and liquid rectification residues; the aqueous liquid hazardous waste specifically includes waste emulsion, waste concentrate, waste paint water, and waste developer.

4. The pretreatment method for waste according to claim 1, characterized in that, the pretreatment center is provided with a deodorizing slightly negative pressure system and a waste liquid stirring tank, and the flammable liquid waste, amphiphilic adsorption carrier, and aqueous liquid hazardous waste are all put into the waste liquid stirring tank for treatment.

5. The pretreatment method for waste according to claim 1, characterized in that, the conveying device includes a rotary forklift.

6. The pretreatment method for waste according to claim 1, characterized in that, the incineration system includes a rotary kiln.

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