CN119819213A - Nitrobenzene wastewater reduction device and method - Google Patents
Nitrobenzene wastewater reduction device and method Download PDFInfo
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Abstract
一种硝基苯废水减量化方法及装置，将酸性硝基苯采用酸洗‑碱洗‑水洗的方式替代传统碱洗‑水洗工艺，将酸洗水和碱洗水分开处理，实现了含酚生物毒性硝基苯碱性废水的减量化，属于有机合成产品分离净化技术领域。本发明实现了酸性硝基苯洗涤过程产生的含酚废水的减量化，含酚碱性废水产生量降低50%‑55%，液碱消耗降低50%‑55%，极大地降低了硝基苯废水预处理装置的投资成本和运行成本，特别适合于混酸硝化的硝基苯产品的洗涤过程。
A method and device for reducing nitrobenzene wastewater, wherein acidic nitrobenzene is treated by acid-alkali-water washing to replace the traditional alkali-water washing process, and the acid washing water and the alkali washing water are treated separately, thereby reducing the amount of phenolic biologically toxic nitrobenzene alkaline wastewater, and belongs to the technical field of separation and purification of organic synthesis products. The present invention reduces the amount of phenolic wastewater generated in the acidic nitrobenzene washing process, reduces the amount of phenolic alkaline wastewater generated by 50%-55%, reduces the consumption of liquid caustic soda by 50%-55%, greatly reduces the investment cost and operation cost of the nitrobenzene wastewater pretreatment device, and is particularly suitable for the washing process of nitrobenzene products of mixed acid nitration.
Description
Technical Field
A nitrobenzene wastewater reduction device and a method belong to the technical field of organic synthesis, and in particular relate to a device and a method for reducing the generation amount of degradation-resistant wastewater in an acidic nitrobenzene water alkali washing process.
Background
In the nitrobenzene production process, benzene is subjected to nitration reaction under the action of mixed acid consisting of sulfuric acid and nitric acid to generate main product nitrobenzene and simultaneously generate dangerous byproducts of nitrophenols, which must be removed. The acidic nitrobenzene is a product obtained by primarily separating the acid remaining in the p-nitrobenzene after the nitration reaction, and contains sulfuric acid, nitric acid, nitrophenol and the like in addition to the main component nitrobenzene. In the industry, generally, acidic nitrobenzene is firstly neutralized and washed by adding dilute alkali solution, sulfuric acid, nitric acid and nitrophenol in the acidic nitrobenzene are all converted into sodium salts and transferred to a water phase, and the sodium salts remained in the nitrobenzene are further washed by adopting a water washing mode after alkaline water and nitrobenzene are separated. And (3) mixing alkaline washing water and water washing water, then, feeding the mixture into a nitrobenzene waste water stripping tower, and obtaining alkaline nitrobenzene waste water from the kettle of the nitrobenzene waste water stripping tower after recycling nitrobenzene in the waste water. The amount of wastewater generated by the method is generally 0.7t wastewater/t acidic nitrobenzene no matter what washing mode is adopted, such as multi-kettle series washing, multi-sprayer series spraying washing and pipeline washing.
The nitrophenol waste water produced by the traditional washing method of acidic nitrobenzene has the nitrophenol content of 50mg/L-150mg/L, has deeper color, large biotoxicity and poor biodegradability, and belongs to phenol-containing waste water which is difficult to degrade and has biotoxicity. The nitrobenzene wastewater can not enter a large biochemical treatment device for wastewater treatment, and complex pretreatment means such as intensified oxidation and the like are needed to be adopted to convert the nitrophenol into biochemical micromolecules and send the biochemical micromolecules to biochemical treatment, thereby bringing high pretreatment cost. For nitrobenzene production enterprises of matched coal chemical enterprises, nitrobenzene wastewater is used as raw material water for pulping pulverized coal for coal blending and incineration, however, for enterprises which are not matched with coal chemical devices, the production amount of nitrobenzene wastewater directly determines the pretreatment cost of the enterprises.
On the other hand, the mixed acid of the acidic nitrobenzene is often not thoroughly separated from the nitrobenzene, a large amount of liquid alkali is consumed by sulfuric acid and nitric acid during direct alkali washing, and the main purpose of the acidic nitrobenzene washing is to remove the dangerous by-product nitrophenol. In the mixed acid nitration process, sulfuric acid is used as a catalyst, water is generated during the nitration reaction, so that the concentration of acid separated from the nitration product becomes thin to about 68wt.%, and the water needs to be evaporated by adopting a vacuum concentration mode, and 86wt.% of concentrated acid is returned for use. In the dilute acid concentration process, the concentrated water with the acid content of 0.3wt.% is also neutralized with the alkaline wastewater generated in the acidic nitrobenzene alkaline water washing process to become non-biochemical nitrobenzene wastewater, so that the nitrobenzene wastewater yield is increased.
Disclosure of Invention
The invention aims to solve the problems of non-biodegradability, high toxicity, high wastewater yield, high pretreatment investment and high operation cost of nitrobenzene wastewater generated by a traditional washing mode, and provides a nitrobenzene wastewater reduction device and a nitrobenzene wastewater reduction method.
The invention provides a combined washing scheme of acid washing, alkali washing and water washing of acidic nitrobenzene, which fully utilizes low-content acid-containing wastewater generated by dilute acid concentration of a nitrobenzene device to wash acidic nitrobenzene firstly, removes most of sulfuric acid and nitric acid which are carried in the acidic nitrobenzene and are not completely separated, then uses a small amount of dilute alkali to neutralize a small amount of mixed acid and nitrophenol remained in the nitrobenzene, and finally further washes inorganic sodium salt and nitrophenol sodium salt in the nitrobenzene by adopting a water washing mode.
The nitrobenzene wastewater reduction device is characterized by comprising a pickling system, an alkaline washing system and a water washing system which are sequentially connected, wherein the pickling system comprises a pickling mixer, a pickling separator, an acid water stripping tower and an acid water stripping tower top condenser, the alkaline washing system comprises an alkaline washing mixer, an alkaline washing separator, an alkaline water stripping tower and an alkaline water stripping tower top condenser, and the water washing system comprises a water washing mixer and a water washing separator.
The invention also provides a nitrobenzene wastewater reduction method adopting the device, which is characterized in that acidic nitrobenzene is pumped into an acid washing mixer by an acidic nitrobenzene conveying pump to be mixed with condensed water from the top of an acidic water stripping tower and acid washing water for supplementing water, residual sulfuric acid and nitric acid in the acidic nitrobenzene are dissolved into water to form a water phase, and nitrobenzene, nitrophenol and a small amount of water form an oil phase; the water phase and oil phase formed in the pickling mixer are separated by oil and water in a pickling separator, the water phase is led out from the top of the pickling separator to an acid water stripping tower, the steam at the top of the acid water stripping tower is condensed by a condenser at the top of the acid water stripping tower and then returned to the pickling mixer for recycling, the acid wastewater of which the organic matters such as nitrobenzene are removed is directly sent to a biochemical system by an acid wastewater conveying pump, the oil phase led out from the bottom of the pickling separator is mixed with dilute alkali liquor in an alkaline washing mixer, the residual dissolved acid, free acid and nitrophenol in the acid nitrobenzene are subjected to neutralization reaction with alkali, sodium sulfate, sodium nitrate and nitrophenol sodium salt are transferred to water to form a water phase, nitrobenzene, a small amount of sodium salt and water form an oil phase, the water phase formed in the alkaline washing separator and water phase are subjected to oil and water-water separation in the alkaline water stripping separator, the water phase is led out from the top of the alkaline water stripping tower to an alkaline water stripping tower, the steam at the top of the alkaline water stripping tower is condensed by an alkaline water stripping tower condenser and then enters the water washing mixer for the next procedure, the alkaline water phase of which is used for removing the organic matters such as nitrobenzene is removed, the alkaline water phase is sent to the alkaline pretreatment mixer, the water phase is further removed from the alkaline water phase, the water phase is led out from the bottom of the water phase in the alkaline water stripping mixer is further washed by the water washing mixer, the water is led out from the water phase from the water separator, the mixed oil-water two phases are subjected to oil-water separation in a water washing separator, water phase led out from the top of the water washing separator and water phase led out from the top of an alkaline washing separator are mixed and enter an alkaline water stripping tower, and oil phase led out from the bottom of the water washing separator is sent to a refining system by a crude nitrobenzene conveying pump.
Generally, the acidic wastewater is acidic wastewater which does not contain nitro phenols and other substances with biotoxicity characteristics, the B/C value is 0.5-0.7, and the acidic wastewater can be used as a pH value regulator to replace sulfuric acid in the biochemical treatment process of wastewater.
The concentration of sulfuric acid in the acidic wastewater is 0.5-wt-7-wt%, and the yield of the wastewater is 30-35% of the volume flow of the acidic nitrobenzene.
The alkaline wastewater is alkaline wastewater with biotoxicity characteristics such as 50mg/L-150mg/L nitrophenols, the B/C value is less than 0.3, and biochemical treatment can be removed after biotoxicity is removed by adopting chemical pretreatment.
The pH value of the alkaline wastewater is 12-13, and the wastewater yield is 30% -35% of the volume flow of the acidic nitrobenzene.
The dilute alkali solution is a 14% -18% NaOH aqueous solution, preferably 15.8%, and the addition amount is 1.2% -1.5% of the volume flow of the acidic nitrobenzene.
The top discharging amount of the acid water stripping tower is 15% -25% of the feeding amount of the acid water stripping tower.
The top blanking amount of the alkaline water stripping tower is 15% -25% of the feeding amount of the alkaline water stripping tower.
The content of 2, 4-dinitrophenol sodium in the crude nitrobenzene is less than or equal to 5mg/L.
The acid washing water is supplied from condensate at the top of the waste acid concentration tower, and the sulfuric acid content is 0.1-0.5 wt.%, preferably 0.3wt.%.
The invention has the advantages that the method and the device for reducing the nitrobenzene wastewater have the advantages that the acid nitrobenzene is respectively and sequentially subjected to acid washing, alkali washing and water washing to respectively generate biochemical acid wastewater and non-biochemical alkaline wastewater, the acid wastewater is directly sent to a wastewater treatment biochemical system to be used as a pH value regulator after being stripped and de-nitrobenzene, and the alkaline wastewater is sent to a nitrophenol wastewater pretreatment procedure after being stripped and recovered. Compared with the traditional alkaline washing-water eluting phenol-removing acid process, the invention can reduce the production of the nondegradable phenol-containing wastewater by 50-55%, reduce the dilute alkali amount required by neutralization by 50-55%, fully utilize soft water resources such as acid wastewater and steam condensate generated by waste acid concentration, reduce the production of alkaline phenol-containing wastewater, and simultaneously reduce the investment cost and operation cost required by alkaline wastewater pretreatment, thereby being particularly suitable for the deacidification and phenol-removing chemical process for preparing nitrobenzene by mixed acid nitration.
Drawings
FIG. 1 is a schematic flow chart of a nitrobenzene wastewater reduction method using the device of the invention.
In the figure, a 1-acidic nitrobenzene tank, a 2-acidic nitrobenzene delivery pump, a 3-pickling mixer, a 4-pickling separator, a 5-alkaline washing mixer, a 6-alkaline washing separator, a 7-water washing mixer, an 8-water washing separator and a 9-crude nitrobenzene delivery pump are shown. 10-acid water stripping tower, 11-acid water stripping tower top condenser, 12-acid waste water conveying pump, 13-alkaline water stripping tower, 14-alkaline water stripping tower top condenser and 15-alkaline waste water conveying pump.
Description of the embodiments
The invention will now be described in detail with reference to the drawings and to specific embodiments.
Examples
Referring to fig. 1, the nitrobenzene wastewater reduction device mainly comprises a pickling system, an alkaline washing system and a water washing system which are sequentially connected, wherein the pickling system comprises a pickling mixer 3, a pickling separator 4, an acid water stripper 10 and an acid water stripper top condenser 11, the alkaline washing system comprises an alkaline washing mixer 5, an alkaline washing separator 6, an alkaline water stripper 13 and an alkaline water stripper top condenser 14, and the water washing system comprises a water washing mixer 7 and a water washing separator 8.
The method for reducing nitrobenzene wastewater adopts the device, and the process flow is shown in the attached figure 1, and specifically comprises the following steps that acidic nitrobenzene in an acidic nitrobenzene storage tank 1 is sent into an acid washing mixer 3 by an acidic nitrobenzene delivery pump 2 to be mixed with condensed water and acid washing water from the top of an acidic water stripping tower 10 in a water supplementing mode, residual sulfuric acid and nitric acid in the acidic nitrobenzene are dissolved into water to form a water phase, and nitrobenzene, nitrophenol and a small amount of water form an oil phase; the water phase and the oil phase formed in the pickling mixer 3 are subjected to oil-water separation in the pickling separator 4, the water phase is led out from the top of the pickling separator 4 to an acid water stripper 10, steam at the top of the acid water stripper 10 is condensed by an acid water stripper overhead condenser 11 and then returned to the pickling mixer 3 for recycling, acid wastewater which is the acid wastewater from which organic matters such as nitrobenzene are removed is directly sent to the kettle of the acid water stripper by an acid wastewater conveying pump 12 for adjusting the pH value of the wastewater to replace sulfuric acid, the oil phase led out from the bottom of the pickling separator 4 is mixed with dilute alkali liquor in the alkaline washing mixer 5, the residual dissolved acid, free acid and nitrophenol in the acid nitrobenzene are subjected to neutralization reaction with alkali, sodium sulfate, sodium nitrate and nitrophenol sodium salt are transferred into water to form water phase, nitrobenzene, a small amount of sodium salt and water form oil phase, the water phase and the oil phase formed in the alkaline washing mixer 5 are subjected to oil-water separation in the alkaline washing separator 6, the water phase is led out from the top of the alkaline water stripper 13 through the alkaline water stripper overhead condenser 14 for condensation, and then enters the water mixer 7 for the next water-steam washing procedure, the alkaline waste water from which organic matters such as nitrobenzene are removed is sent to waste water treatment by an alkaline waste water conveying pump 15 at the tower bottom of an alkaline water stripping tower 13, oil phase led out from the bottom of an alkaline water stripping tower 6 is mixed with condensed water from the tower top of the alkaline water stripping tower 13 and water replenishing water of water washing water in a water washing mixer 7, sodium salt remained in the oil phase nitrobenzene is further removed by washing, oil-water separation is carried out on the mixed oil-water two phases in a water washing separator 8, water phase led out from the top of the water washing separator 8 and water phase led out from the top of the alkaline water stripping tower 13 are mixed, and oil phase led out from the bottom of the water washing separator 8 is sent to a refining system by a crude nitrobenzene conveying pump 9.
Example 1
In a nitrobenzene device, the nitrobenzene yield is 9 ten thousand tons/year, the flow rate of acidic nitrobenzene is 12.5m 3/h, and the waste water yield of the original alkaline washing-water washing process is 8m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.53, and the sulfuric acid concentration in the acid wastewater is 5 wt percent. The yield of the acid wastewater is 4.13m 3/h, which is 33 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has 80mg/L of nitrophenol, a pH value of 12, a B/C value of 0, and an alkaline wastewater volume of 3.87m 3/h which is 31 percent of the volume flow of acidic nitrobenzene. In the alkaline washing process, 15.8 wt percent of dilute alkali liquor 175L/h is added, which is 1.4 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 20% and the alkaline water stripper had a feed of 18%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 3.7m 3/h, and the volume flow rate of the acid nitrobenzene is 29.6%. The sodium nitrophenolate (calculated as sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 4.2 mg/L.
Example 2
In a nitrobenzene device, the nitrobenzene yield is 19 ten thousand tons/year, the flow rate of acidic nitrobenzene is 26m 3/h, and the waste water yield of the primary alkali washing-water washing process is 17m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.68, and the sulfuric acid concentration in the acid wastewater is 0.5 wt percent. The yield of the acid wastewater is 7.8 m 3/h, which is 30 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has the nitrophenol content of 50mg/L, the pH value of 12, the B/C value of 0, and the alkaline wastewater volume of 9.1 m 3/h which is 35 percent of the volume flow of acidic nitrobenzene. 15.8 wt percent of dilute alkali liquor 390L/h is added in the alkaline washing process, which is 1.5 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 15% and the alkaline water stripper had a feed of 25%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 8.71 m 3/h, and the volume flow rate of the acidic nitrobenzene is 33.5%. The sodium nitrophenolate (calculated as sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 3.5 mg/L.
Example 3
In a nitrobenzene device, the nitrobenzene yield is 29 ten thousand tons/year, the acidic nitrobenzene flow is 36m 3/h, and the waste water yield of the primary alkali washing-water washing process is 25m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.61, and the sulfuric acid concentration in the acid wastewater is 7 wt percent. The yield of the acid wastewater is 12.6 m 3/h, which is 35 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has the nitrophenol content of 150mg/L, the pH value of 12, the B/C value of 0, and the alkaline wastewater volume of 10.8m 3/h which is 30 percent of the volume flow of the acidic nitrobenzene. 15.8 wt percent of dilute alkali liquor 432L per hour is added in the alkaline washing process, which is 1.2 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 25% and the alkaline water stripper had a feed of 15%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 10.37 m 3/h, and the volume flow of the acid nitrobenzene is 28.8%. The sodium nitrophenolate (calculated as sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 4.8 mg/L.
Example 4
In a nitrobenzene device, the nitrobenzene yield is 5 ten thousand tons/year, the acidic nitrobenzene flow is 6m 3/h, and the waste water yield of the primary alkali washing-water washing process is 4.2 m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.5, and the sulfuric acid concentration in the acid wastewater is 2 wt percent. The yield of the acid wastewater is 1.9 m 3/h, which is 32 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has the nitrophenol content of 100 mg/L, the pH value of 12.5, the B/C value of 0.1, and the alkaline wastewater volume of 1.86 m 3/h which is 31 percent of the volume flow of acidic nitrobenzene. During the alkaline washing process, 15.8 wt percent of dilute alkali liquor 78L per hour is added, which is 1.3 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 20% and the alkaline water stripper had a feed of 22%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 1.82 m 3/h, and the volume flow rate of the acid nitrobenzene is 30.4%. The sodium nitrophenolate (calculated by sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 3 mg/L.
Example 5
In a nitrobenzene device, the nitrobenzene yield is 15 ten thousand tons/year, the acidic nitrobenzene flow is 18.6 m 3/h, and the waste water yield of the original alkaline washing-water washing process is 13m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.65, and the sulfuric acid concentration in the acid wastewater is 4 wt percent. The yield of the acid wastewater is 6.3m 3/h, which is 34 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has the nitrophenol content of 120mg/L, the pH value of 12.4, the B/C value of 0.2, and the alkaline wastewater volume of 6.3m 3/h which is 34 percent of the volume flow of acidic nitrobenzene. During the alkaline washing process, 15.8 wt percent of dilute alkali liquor 260L per hour is added, which is 1.4 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 18% and the alkaline water stripper had a feed of 21%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 10.37 m 3/h, and the volume flow of the acid nitrobenzene is 28.8%. The sodium nitrophenolate (calculated as sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 4.8 mg/L.
Example 6
In a nitrobenzene device, the nitrobenzene yield is 35 ten thousand tons/year, the acidic nitrobenzene flow is 43.5m 3/h, and the waste water yield of the original alkaline washing-water washing process is 30.5 m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.65, and the sulfuric acid concentration in the acid wastewater is 5.6 wt percent. The yield of the acid wastewater is 13.9 m 3/h, which is 32 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has the nitrophenol content of 80 mg/L, the pH value of 12.3, the B/C value of 0, and the alkaline wastewater volume of 14.8m 3/h which is 34 percent of the volume flow of acidic nitrobenzene. 15.8 wt percent of dilute alkali liquor 609L per hour is added in the alkaline washing process, which is 1.4 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 23% and the alkaline water stripper had a feed of 19%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 14.2 m 3/h, and the volume flow rate of the acidic nitrobenzene is 32.6%. The sodium nitrophenolate (calculated as sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 3.2 mg/L.
Example 7
In a nitrobenzene device, the nitrobenzene yield is 10 ten thousand tons/year, the acidic nitrobenzene flow is 12.4m 3/h, and the waste water yield of the original alkaline washing-water washing process is 8.7 m 3/h. After the acid washing, alkali washing and water washing modification by adopting the device of the embodiment, the B/C value of the acid wastewater is 0.58, and the sulfuric acid concentration in the acid wastewater is 6 wt percent. The yield of the acid wastewater is 4.0 m 3/h, which is 32 percent of the volume flow of the acid nitrobenzene. The produced alkaline wastewater has the nitrophenol content of 90 mg/L, the pH value of 12.8, the B/C value of 0.5, and the alkaline wastewater volume of 3.8m 3/h which is 31 percent of the volume flow of acidic nitrobenzene. 15.8 wt percent of dilute alkali liquor 161L/h is added in the alkaline washing process, which is 1.3 percent of the volume flow of the acidic nitrobenzene. The sour water stripper had a feed of 24% and the alkaline water stripper had a feed of 22%. The water washing water is supplemented by the recycled steam condensate water, the water supplementing amount is 3.64 m 3/h, and the volume flow rate of the acid nitrobenzene is 29.3%. The sodium nitrophenolate (calculated as sodium 2, 4-dinitrophenolate) content in the crude nitrobenzene after acid washing, alkali washing and water washing is 3.1 mg/L.
The comparative example is that the existing nitrobenzene device adopts an isothermal nitration process, the nitrobenzene yield is 29 ten thousand tons/year, the acid nitrobenzene flow is 36m 3/h, the waste water yield of an alkaline washing-water washing process is 25m 3/h, an alkaline washing neutralization and secondary water washing process is adopted, alkaline washing water and water washing water are mixed and then are sent to an alkaline waste water stripping tower, the stripped alkaline waste water yield is 22m 3/h, the tower top condensate is supplemented to a water washing section, and the alkaline consumption is larger due to the fact that part of sulfuric acid and nitric acid are entrained in the acid nitrobenzene, the addition amount of dilute alkali of 15.8% is 950L/h, and the total amount is 1.16t/h. The sodium nitrophenolate content in the generated alkaline wastewater is 130mg/L, and the pH value is 12.5.
As can be seen from the above examples, the acidic nitrobenzene after the primary separation of the products by the nitration reaction is washed with water by concentrating water with dilute acid, then is neutralized by adding a small amount of dilute alkali to remove residual sulfuric acid, nitric acid and nitrophenol, and finally is washed with steam condensate or other soft water. The method comprises the steps of feeding the acid waste water after acid washing into a biochemical treatment to adjust the pH value to replace 86 wt percent of sulfuric acid, recycling tower top condensate for acid washing, feeding the tower bottom effluent of the alkaline nitrobenzene waste water after alkaline water washing into a pretreatment process after alkaline water stripping, and returning the tower top condensate of the alkaline stripping for water washing. Compared with the traditional alkaline washing-water washing process of the acidic nitrobenzene, the production amount of the alkaline nitrobenzene wastewater is reduced by 50-55%, the alkaline consumption is reduced by 50-55%, and the investment cost and the operation cost required by the pretreatment of the alkaline nitrobenzene wastewater are reduced, so that the method is particularly suitable for the washing neutralization phenol removal process of the acidic nitrobenzene.
Claims (12)
1. A nitrobenzene wastewater reduction device is characterized by comprising a pickling system, an alkaline washing system and a water washing system which are sequentially connected, wherein the pickling system comprises a pickling mixer, a pickling separator, an acidic water stripping tower and an acidic water stripping tower top condenser, the alkaline washing system comprises an alkaline washing mixer, an alkaline washing separator, an alkaline water stripping tower and an alkaline water stripping tower top condenser, and the water washing system comprises a water washing mixer and a water washing separator.
2. A nitrobenzene wastewater reduction method adopting the device of claim 1, which is characterized in that acidic nitrobenzene is pumped into an acid washing mixer by an acidic nitrobenzene conveying pump to be mixed with condensed water from the top of an acidic water stripping tower and acid washing water for supplementing water, residual sulfuric acid and nitric acid in the acidic nitrobenzene are dissolved into water to form a water phase, and nitrobenzene, nitrophenol and a small amount of water form an oil phase; the water phase and oil phase formed in the pickling mixer are separated by oil and water in a pickling separator, the water phase is led out from the top of the pickling separator to an acid water stripping tower, the steam at the top of the acid water stripping tower is condensed by a condenser at the top of the acid water stripping tower and then returned to the pickling mixer for recycling, the acid wastewater with the organic matters removed is directly sent to a biochemical system by an acid wastewater conveying pump, the oil phase led out from the bottom of the pickling separator is mixed with dilute alkali liquor in an alkaline washing mixer, the residual dissolved acid, free acid and nitrophenol in the acid nitrobenzene are subjected to neutralization reaction with alkali, sodium sulfate salt, sodium nitrate and nitrophenol sodium salt are transferred to water to form the water phase, nitrobenzene, a small amount of sodium salt and water form the oil phase, the water phase and the water phase formed in the alkaline washing mixer are subjected to oil and water separation in the alkaline washing separator, the water phase and the water phase formed in the alkaline washing separator are led out from the top of the alkaline water stripping tower to the alkaline water stripping tower, the steam at the top of the alkaline water stripping tower is led out from the condenser of the alkaline water stripping tower and then enters the water washing mixer for the next procedure, the alkaline water stripping tower is the alkaline wastewater with the alkaline waste water removed organic matters removed alkaline waste water is sent out from the alkaline water stripping tower by an alkaline pretreatment pump, the water phase is further removed from the water phase is sent to the water phase and the water phase is further led out from the bottom of the water washing mixer to the water stripping tower to the water separator, the mixed oil-water two phases are subjected to oil-water separation in a water washing separator, water phase led out from the top of the water washing separator and water phase led out from the top of an alkaline washing separator are mixed and enter an alkaline water stripping tower, and oil phase led out from the bottom of the water washing separator is sent to a refining system by a crude nitrobenzene conveying pump.
3. The method for reducing nitrobenzene wastewater according to claim 2, wherein the acidic wastewater is acidic wastewater which does not contain nitrophenols and has biotoxic characteristic substances, the B/C value is 0.5-0.7, and the acidic wastewater is used as a pH regulator instead of sulfuric acid in the biochemical treatment process of wastewater.
4. The nitrobenzene wastewater reduction method according to claim 2 or 3, characterized in that the sulfuric acid concentration in the acidic wastewater is 0.5 wt to 7 wt%, and the wastewater yield is 30 to 35% of the volume flow of acidic nitrobenzene.
5. The method for reducing nitrobenzene waste water as in claim 2, wherein said alkaline waste water is alkaline waste water containing 50mg/L to 150 mg/L of nitrophenols having biotoxicity characteristics, the B/C value is less than 0.3, and the biochemical treatment is performed after the biotoxicity is removed by chemical pretreatment.
6. The nitrobenzene wastewater reduction method according to claim 2 or 5, characterized in that the pH value of the alkaline wastewater is 12-13, and the wastewater yield is 30% -35% of the volume flow of acidic nitrobenzene.
7. The nitrobenzene wastewater reduction method according to claim 2, characterized in that the dilute alkali solution is 14% -18% NaOH aqueous solution, preferably 15.8%, and the addition is 1.2% -1.5% of the volume flow of acidic nitrobenzene.
8. The nitrobenzene wastewater reduction method as claimed in claim 2, wherein the acid water stripper overhead feed amount is 15% -25% of the feed amount.
9. The nitrobenzene wastewater reduction method as claimed in claim 2, wherein the amount of the top discharge of the alkaline water stripper is 15% -25% of the amount of the feed.
10. The nitrobenzene wastewater reduction method according to claim 2, characterized in that the water wash water make-up is recycled steam condensate or other soft water, the make-up amount is 28% -34% of the volume flow of acidic nitrobenzene.
11. The method for reducing nitrobenzene wastewater according to claim 2, wherein the amount of sodium 2, 4-dinitrophenolate in said crude nitrobenzene is 5mg/L or less.
12. The nitrobenzene wastewater reduction method according to claim 2, characterized in that the acid washing water is supplemented from condensate water at the top of the waste acid concentration tower, and the sulfuric acid content is 0.1% -0.5%, preferably 0.3%.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1680198A (en) * | 2004-04-10 | 2005-10-12 | 拜尔材料科学股份公司 | Method for treating waste water containing aromatic nitro compounds |
| US20070249873A1 (en) * | 2006-02-03 | 2007-10-25 | Thomas Knauf | Process for the production of nitrobenzene |
| CN102432410A (en) * | 2011-09-21 | 2012-05-02 | 沈阳化工大学 | Production method of nitro compounds by tubular continuous nitrification reaction |
| CN102471092A (en) * | 2009-08-18 | 2012-05-23 | 诺拉姆国际公司 | Scrubbing systems for nitroaromatics |
| CN105263865A (en) * | 2013-04-18 | 2016-01-20 | 科思创德国股份公司 | Method for reprocessing wastewater from nitrobenzene production |
| CN106278902A (en) * | 2015-06-08 | 2017-01-04 | 中国石油化工股份有限公司 | A kind of reduce the method for sodium salt content in thick Nitrobenzol |
| CN106660934A (en) * | 2014-06-24 | 2017-05-10 | 科思创德国股份有限公司 | Process for producing nitrobenzene |
| CN113248385A (en) * | 2021-05-31 | 2021-08-13 | 中石化南京化工研究院有限公司 | Method for reducing alkali consumption of acidic nitrobenzene |
| CN115397779A (en) * | 2020-04-27 | 2022-11-25 | 科思创德国股份有限公司 | Process for Purifying Aqueous Wastewater Streams Contaminated with Nitrobenzene |
-
2023
- 2023-10-13 CN CN202311327049.3A patent/CN119819213A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1680198A (en) * | 2004-04-10 | 2005-10-12 | 拜尔材料科学股份公司 | Method for treating waste water containing aromatic nitro compounds |
| US20070249873A1 (en) * | 2006-02-03 | 2007-10-25 | Thomas Knauf | Process for the production of nitrobenzene |
| CN102471092A (en) * | 2009-08-18 | 2012-05-23 | 诺拉姆国际公司 | Scrubbing systems for nitroaromatics |
| CN102432410A (en) * | 2011-09-21 | 2012-05-02 | 沈阳化工大学 | Production method of nitro compounds by tubular continuous nitrification reaction |
| CN105263865A (en) * | 2013-04-18 | 2016-01-20 | 科思创德国股份公司 | Method for reprocessing wastewater from nitrobenzene production |
| CN106660934A (en) * | 2014-06-24 | 2017-05-10 | 科思创德国股份有限公司 | Process for producing nitrobenzene |
| CN106278902A (en) * | 2015-06-08 | 2017-01-04 | 中国石油化工股份有限公司 | A kind of reduce the method for sodium salt content in thick Nitrobenzol |
| CN115397779A (en) * | 2020-04-27 | 2022-11-25 | 科思创德国股份有限公司 | Process for Purifying Aqueous Wastewater Streams Contaminated with Nitrobenzene |
| CN113248385A (en) * | 2021-05-31 | 2021-08-13 | 中石化南京化工研究院有限公司 | Method for reducing alkali consumption of acidic nitrobenzene |
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