Acetyl rectification residual liquid treatment method

Abstract

The invention provides an acetyl rectification residual liquid treatment method. The method comprises the following steps: uniformly laying a sawdust layer in a reaction container; saw dust and slaked lime are uniformly mixed and stirred to form a mixture, and the mixture is flatly laid on the saw dust layer in the reaction container; covering a layer of plate frame sludge on the uppermost layer of the reaction container; finally, the reaction container added with the auxiliary materials is moved to a closed reaction room and covered with a gas collecting hood, and a pipeline is connected to the gas collecting hood and connected into an induced draft system of an incinerator; inserting a waste liquid pipeline into the reaction container; and pumping the acetyl rectification residual liquid into the reaction container for auxiliary material reaction. According to the method, slaked lime is added for treatment before incineration, acid elements (sulfur, chlorine, phosphorus and the like) in the slaked lime can react with Ca < 2 + > to generate stable divalent salt, the divalent salt can be removed in an incineration hearth in a slag incineration mode during later incineration, and low-boiling-point sylvite or sodium salt is prevented from being formed and entering the rear end of an incineration system boiler to be scaled and blocked; and the stability and continuity of system production are greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of acetyl distillation residual liquid treatment, and relates to a method for treating acetyl distillation residual liquid. Background Art

[0002] Acetyl distillation residue is the wastewater generated by the pesticide industry in the production process of pesticide intermediates, that is, 91% spermine reacts with dimethyl sulfate to generate methyl parathion after transposition reaction, and then acetic anhydride and concentrated sulfuric acid are added to carry out acylation reaction in the acetyl production device to generate methyl parathion. The acetyl wastewater generated in the pollution-producing link of the reaction is acetyl distillation residue, which has the characteristics of high calorific value, strong odor and strong toxicity.

[0003] The characteristic of acetyl is that its calorific value is about 5000-6000kcal / kg, total phosphorus is about 0.5-5%, total sulfur is about 3-7%, and total chlorine is about 0.5-2%. Studies have found that due to the high content of acidic elements such as sulfur, chlorine, and phosphorus in the acetyl distillation residue, the acidic elements and low-price K+ and Na+ ions form low-boiling salts such as potassium and sodium during the disposal process, causing frequent scaling and blockage of the incineration system boiler and the back-end process equipment of the boiler, thereby affecting the negative pressure and production stability of the incineration system, and even causing the incineration system to stop production; and the acidic elements consume a large amount of liquid alkali in the back-end flue gas treatment section, and the disposal cost remains high; secondly, the calorific value of the acetyl distillation residue is too high. Under the condition that the system design heat load is determined, the disposal of the acetyl distillation residue will have a greater negative impact on the system production capacity. Summary of the invention

[0004] The purpose of the present invention is to provide a method for treating acetyl distillation residue in view of the defects of the prior art, which can significantly reduce its calorific value and solidify it, thereby improving the treatment efficiency, avoiding blockage at the rear end of the system, and improving the stability and continuity of the subsequent incineration system production.

[0005] The technical purpose of the present invention is achieved through the following technical scheme: a method for treating acetyl distillation residue, comprising:

[0006] Evenly laying a layer of sawdust in a reaction container, wherein only the top of the reaction container is open;

[0007] Separately, sawdust and slaked lime in a mass ratio of 1:1-1:1.5 are mixed and stirred to form a mixture;

[0008] spreading a mixture of sawdust and slaked lime on the sawdust layer in the reaction vessel;

[0009] Cover the top layer of the reaction vessel with a layer of plate and frame sludge, and evenly spread and cover it with sawdust to ensure that no sawdust is exposed;

[0010] Finally, move the reaction container with the auxiliary materials added to the closed reaction room, cover it with a gas collecting hood, leave a corner gap, connect the pipeline to the gas collecting hood and connect it to the induced draft system of the incinerator;

[0011] Inserting a waste liquid pipeline into the reaction container, pumping the acetyl distillation residual liquid into the reaction container, so that the acetyl distillation residual liquid infiltrates into the lower layer of the reaction container and reacts with the auxiliary material;

[0012] After extracting the residual liquid from acetyl distillation, cover the gas collecting hood tightly and let it stand under negative pressure to allow for full reaction.

[0013] Preferably, the laying thickness of the plate and frame sludge is 20-40 cm.

[0014] Preferably, the sawdust layer is laid with a thickness of 10-15 cm.

[0015] Preferably, the reaction time is controlled to be 10-14h.

[0016] Preferably, after the acetyl distillation residue is completely reacted, the gas collecting hood is opened, and low calorific value aqueous waste liquid with a calorific value of <1000 kcal / kg, a density of ≤1.1 kg / L, and a pH of 4-10 is injected into the reaction container to cool the reaction solids for no less than 2 hours.

[0017] Preferably, the injection amount of the low calorific value aqueous waste liquid is 1.5-2 times the mass of slaked lime.

[0018] Preferably, after the core temperature of the solid in the reaction container is lower than 40° C., the residue in the reaction container is poured into an incineration pit, mixed evenly with other waste materials, and then incinerated.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a method for treating acetyl distillation residual liquid. The present invention adds slaked lime for treatment before incineration, which helps the acidic elements (sulfur, chlorine, phosphorus, etc.) therein to react with Ca2+ to form stable divalent salts. During the later incineration, the acidic elements (sulfur, chlorine, phosphorus, etc.) can be removed in the incineration furnace in the form of incineration slag, thereby preventing the formation of low-boiling-point potassium salt or sodium salt that enters the rear end of the incineration system boiler to form scale and blockage; thus greatly improving the stability and continuity of system production.

[0021] 2. The raw material used in the pretreatment of the present invention is slaked lime, which has low cost. Through the pretreatment in the early stage, the consumption of liquid alkali at the rear end of incineration can be reduced, which greatly saves costs and improves economic benefits. The calorific value of the acetyl distillation residue is greatly reduced during the pretreatment process, from about 6000 kcal to about 3000 kcal. Under the condition that the system design heat load remains unchanged, the system capacity is greatly improved, and more acetyl distillation residue can be consumed.

[0022] 3. The acetyl distillation residue has a strong odor, which is particularly severe during the pre-treatment reaction with slaked lime. The present invention reduces the intensity of the reaction between the acetyl distillation residue and slaked lime by mixing sawdust and slaked lime and then contacting and reacting with the acetyl distillation residue. However, due to the heat preservation effect of sawdust, the reaction time of the acetyl distillation residue and slaked lime can be prolonged. At the same time, the steam and gas generated by the reaction are directly drawn into the incinerator by the incineration induced draft system for treatment. The odor of the entire reaction process is controllable, no smoke and odor escape, and environmental pollution is eliminated.

[0023] 4. The solid-liquid ratio of the feed in the existing hazardous waste incineration system is about 7:3, while the hazardous waste incinerated on the market now basically has more liquid than solid, which brings difficulties to the incineration of hazardous waste. The method provided by the present invention converts the acetyl distillation residue into a solid through pretreatment technology, which can effectively reduce the inventory of liquid materials and improve the hazardous waste treatment capacity. At the same time, since the pretreatment reaction of the acetyl distillation residue is exothermic, the low calorific value aqueous waste liquid is consumed to cool down, thereby realizing the coordinated disposal of the low calorific value aqueous waste liquid.

[0024] 5. During the static reaction of the acetyl distillation residue, heat is released and steam is generated. At the same time, due to the heat preservation effect of sawdust, the reaction between the acetyl distillation residue and slaked lime can be promoted more thoroughly. When the reaction is most intense, the core temperature of the container can exceed 100°C, but the sawdust is only carbonized under the condition of sludge isolating from the air without the risk of fire. In addition, the steam and gas generated by the reaction are immediately drawn into the incinerator through the induced draft system for treatment, and no smoke or odor escapes during the reaction. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the examples are only used for illustrative purposes and cannot be construed as limitations on this patent.

[0026] Example 1

[0027] This embodiment provides a method for treating acetyl distillation residue, comprising the following steps:

[0028] First, a sawdust layer with a thickness of 10 cm is evenly laid in a reaction container, wherein only the top of the reaction container is open;

[0029] Separately, 100 parts sawdust and 150 parts slaked lime were mixed and stirred to form a mixture;

[0030] spreading a mixture of sawdust and slaked lime on the sawdust layer in the reaction vessel;

[0031] Cover the top layer of the reaction vessel with a layer of plate and frame sludge, evenly spread and cover with sawdust, the thickness of the plate and frame sludge is 20cm, and ensure that no sawdust is exposed;

[0032] Finally, move the reaction container with the auxiliary materials added to the closed reaction room, cover it with a gas collecting hood, leave a corner gap, connect the pipeline to the gas collecting hood and connect it to the induced draft system of the incinerator;

[0033] Inserting a waste liquid pipeline into the reaction container, pumping the acetyl distillation residual liquid into the reaction container, so that the acetyl distillation residual liquid infiltrates into the lower layer of the reaction container and reacts with the auxiliary material;

[0034] After the residual liquid of acetyl distillation is extracted, the gas collecting hood is tightly covered and allowed to stand under negative pressure for full reaction. The reaction time is controlled to be 10 hours.

[0035] After the acetyl distillation residue is completely reacted, open the gas hood and inject low calorific value aqueous waste liquid into the reaction vessel. High calorific value waste liquid refers to waste liquid with a calorific value of more than 3000 calories. This waste liquid can be directly burned or use its own energy in industrial production, such as methanol and styrene in the petrochemical industry. Low calorific value waste liquid refers to waste liquid with a calorific value of less than 3000 calories, such as acidic waste liquid or alkaline waste liquid after solid waste incineration treatment. The calorific value is required to be less than 1000kcal / kg, the density is ≤1.1kg / L, and the pH is 4-10. The reaction solid is cooled for a cooling time of not less than 2h. The injection amount of the low calorific value aqueous waste liquid is 300-400L.

[0036] Example 2

[0037] This embodiment provides a method for treating acetyl distillation residue, comprising the following steps:

[0038] First, a layer of sawdust with a thickness of 15 cm is evenly laid in a reaction container, wherein only the top of the reaction container is open;

[0039] Separately, 150 kg of sawdust and 200 kg of slaked lime were mixed and stirred to form a mixture;

[0040] spreading a mixture of sawdust and slaked lime on the sawdust layer in the reaction vessel;

[0041] Cover the top layer of the reaction vessel with a layer of plate and frame sludge, evenly spread and cover with sawdust, the thickness of the plate and frame sludge is 40cm, and ensure that no sawdust is exposed;

[0042] Finally, move the reaction container with the auxiliary materials added to the closed reaction room, cover it with a gas collecting hood, leave a corner gap, connect the pipeline to the gas collecting hood and connect it to the induced draft system of the incinerator;

[0043] Inserting a waste liquid pipeline into the reaction container, pumping the acetyl distillation residual liquid into the reaction container, so that the acetyl distillation residual liquid infiltrates into the lower layer of the reaction container and reacts with the auxiliary material;

[0044] After the residual liquid of acetyl distillation is extracted, the gas collecting hood is tightly covered and allowed to stand under negative pressure for full reaction. The reaction time is controlled to be 14 hours.

[0045] After the acetyl distillation residue is completely reacted, open the gas collecting hood and inject low calorific value aqueous waste liquid into the reaction vessel, with a calorific value of <1000kcal / kg, a density of ≤1.1kg / L, and a pH of 4-10, to cool the reaction solids for no less than 2 hours. The injection amount of the low calorific value aqueous waste liquid is 300-400L.

[0046] Example 3

[0047] This embodiment provides a method for treating acetyl distillation residue, comprising the following steps:

[0048] First, a sawdust layer with a thickness of 10 cm is evenly laid in a reaction container, wherein only the top of the reaction container is open;

[0049] Separately, 100 parts sawdust and 150 parts slaked lime were mixed and stirred to form a mixture;

[0050] spreading a mixture of sawdust and slaked lime on the sawdust layer in the reaction vessel;

[0051] Cover the top layer of the reaction vessel with a layer of plate and frame sludge, evenly spread and cover with sawdust, the thickness of the plate and frame sludge is 20cm, and ensure that no sawdust is exposed;

[0052] Finally, move the reaction container with the auxiliary materials added to the closed reaction room, cover it with a gas collecting hood, leave a corner gap, connect the pipeline to the gas collecting hood and connect it to the induced draft system of the incinerator;

[0053] Inserting a waste liquid pipeline into the reaction container, pumping the acetyl distillation residual liquid into the reaction container, so that the acetyl distillation residual liquid infiltrates into the lower layer of the reaction container and reacts with the auxiliary material;

[0054] After the residual liquid of acetyl distillation is extracted, the gas collecting hood is tightly covered and allowed to stand under negative pressure for full reaction. The reaction time is controlled to be 10 hours.

[0055] After the acetyl distillation residue is completely reacted, open the gas collecting hood and inject low calorific value aqueous waste liquid into the reaction vessel, with a calorific value of <1000kcal / kg, a density of ≤1.1kg / L, and a pH of 4-10, to cool the reaction solids for no less than 2 hours. The injection amount of the low calorific value aqueous waste liquid is 300-400L.

[0056] In the above embodiment, after the core temperature of the solid in the reaction container is lower than 40° C., the residue in the reaction container is poured into the incineration pit, mixed evenly with other waste materials, and then incinerated.

[0057] Before treatment, the relevant indicators of the acetyl distillation residue were tested, and the relevant test data are shown in Table 1:

[0058]

[0059]

[0060] Table 1

[0061] The products obtained after the treatment of the above-mentioned Example 1 and the Example were sampled and tested to compare and analyze with relevant test indicators to verify the effect and degree of the treatment process. After testing, the test indicators of the product obtained after the treatment of Example 1 are shown in Table 2:

[0062]

[0063] Table 2

[0064] The detection indexes of the product obtained after treatment in Example 2 are shown in Table 3:

[0065]

[0066] Table 3

[0067] By comparing the test indicators before and after treatment, it can be seen that the contents of P, S and Cl in the treated product are much lower than the original level. The slaked lime has a good fixation effect on P, S and Cl in acetyl, which further supports the feasibility of this disposal method.

[0068] After testing, it was verified that the calorific value of the acetyl distillation residue was greatly reduced during the reaction with raw and auxiliary materials, from 6000 kcal to about 3000 kcal. When the system design heat load was determined, the system production capacity was greatly improved.

[0069] In the above-mentioned embodiment, slaked lime is added for treatment before incineration, which helps the acidic elements (sulfur, chlorine, phosphorus, etc.) therein to react with Ca2+ to form stable divalent salts. During the later incineration, they can be removed in the incineration furnace in the form of incineration slag to avoid the formation of low-boiling point potassium salts or sodium salts that enter the rear end of the incineration system boiler to form scale and blockage; the stability and continuity of the system production are greatly improved.

[0070] The raw material used in the pretreatment of the above embodiment is slaked lime, which has low cost. Through the early pretreatment, the consumption of liquid alkali at the rear end of incineration can be reduced, which greatly saves costs and improves economic benefits. The calorific value of the acetyl distillation residue is greatly reduced during the pretreatment process, from about 6000 kcal to about 3000 kcal. Under the condition that the system design heat load remains unchanged, the system capacity is greatly improved, and more acetyl distillation residue can be consumed.

[0071] The acetyl distillation residue has a strong odor, and the odor is particularly strong during the pre-treatment reaction with slaked lime. The present invention can reduce the intensity of the reaction between the acetyl distillation residue and the slaked lime by mixing sawdust and slaked lime and then contacting and reacting with the acetyl distillation residue. However, due to the heat preservation effect of sawdust, the reaction time of the acetyl distillation residue and the slaked lime can be prolonged. At the same time, the steam and gas generated by the reaction are directly sucked into the incinerator by the incineration induced draft system for treatment. The odor of the entire reaction process is controllable, no smoke and odor escape, and environmental pollution is eliminated.

[0072] The solid-liquid ratio of the feed in the existing hazardous waste incineration system is about 7:3, and the hazardous waste incineration on the market now basically has more liquid than solid, which brings difficulties to the incineration of hazardous waste. The method provided by the present invention converts the acetyl distillation residue into a solid through pretreatment technology, which can effectively reduce the inventory of liquid materials and improve the hazardous waste treatment capacity. At the same time, because the pretreatment reaction of the acetyl distillation residue is exothermic, it consumes a large amount of low calorific value aqueous waste liquid for cooling, thereby realizing the coordinated disposal of low calorific value aqueous waste liquid.

[0073] During the static reaction of the acetyl distillation residue, heat is released and steam is generated. At the same time, due to the heat preservation effect of sawdust, the reaction between the acetyl distillation residue and slaked lime is promoted to be more thorough. When the reaction is most intense, the core temperature of the container can exceed 100°C, but the sawdust only carbonizes under the condition of sludge isolating from the air and there is no risk of fire. In addition, the steam and gas generated by the reaction are immediately drawn into the incinerator for treatment through the induced draft system, and no smoke or odor escapes during the reaction process.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for treating acetyl distillation residue, characterized in that: include: Evenly laying a layer of sawdust in a reaction container, wherein only the top of the reaction container is open; Separately, sawdust and slaked lime in a mass ratio of 1:1-1:1.5 are mixed and stirred to form a mixture; spreading a mixture of sawdust and slaked lime on the sawdust layer in the reaction vessel; Cover the top layer of the reaction vessel with a layer of plate and frame sludge, and evenly spread and cover it with sawdust to ensure that no sawdust is exposed; Finally, move the reaction container with the auxiliary materials added to the closed reaction room, cover it with a gas collecting hood, leave a corner gap, connect the pipeline to the gas collecting hood and connect it to the induced draft system of the incinerator; Inserting a waste liquid pipeline into the reaction container, pumping the acetyl distillation residual liquid into the reaction container, so that the acetyl distillation residual liquid infiltrates into the lower layer of the reaction container and reacts with the auxiliary material; After extracting the residual liquid from acetyl distillation, cover the gas collecting hood tightly and let it stand under negative pressure to allow for full reaction.

2. The method for treating acetyl distillation residue according to claim 1, wherein: The laying thickness of plate and frame sludge is 20-40cm.

3. The method for treating acetyl distillation residue according to claim 1, characterized in that: The thickness of the sawdust layer is 10-15cm.

4. The method for treating acetyl distillation residue according to claim 1, characterized in that: The reaction time is controlled to be 10-14h.

5. The method for treating acetyl distillation residue according to claim 1, characterized in that: After the acetyl distillation residue has reacted completely, open the gas collecting hood and inject low calorific value aqueous waste liquid into the reaction vessel, with a calorific value of <1000kcal / kg, a density of ≤1.1kg / L, and a pH of 4-10, to cool the reaction solids for no less than 2h.

6. The method for treating acetyl distillation residue according to claim 5, characterized in that: The injection amount of the low calorific value aqueous waste liquid is 1.5-2 times the mass of slaked lime.

7. The method for treating acetyl distillation residue according to claim 5, characterized in that: When the core temperature of the solid in the reaction container is lower than 40°C, pour the residue in the reaction container into the incineration pit, mix it with other waste materials, and then incinerate it.

Images