During cyclohexane oxidation decomposes and the treatment process of saponification waste lye
<one〉technical field:
The present invention relates in a kind of cyclohexane oxidation decomposition and the treatment process of saponification waste lye.
<two〉background technology:
Prepare in the production process of pimelinketone and hexalin at cyclohexane oxidation, the deep oxidation side reaction takes place in some hexanaphthene in oxidation reactor, generate organic carboxyl acid and ester, the cyclohexyl hydroperoxide of cyclohexane oxidation generation simultaneously is in decomposition course, also to generate a part of organic carboxyl acid, during these organic carboxyl acids and ester carry out with the NaOH aqueous solution and saponification reaction, make it to remove, will generate the waste lye that contains organic carboxylic acid sodium salt, this waste lye is called in the cyclohexane oxidation decomposition and saponification waste lye, is called for short waste lye.This waste lye contains monobasic low carbon acid sodium 5%~10% (comprising sodium acetate, Sodium Propionate, Sodium propanecarboxylate, natrium valericum), diprotic acid sodium 3%~6% (comprising Soduxin, Sodium glutarate, hexanodioic acid sodium), hydroxycaproic acid sodium and condenses 10%~20% thereof, yellow soda ash 3%~8%, sodium hydroxide 0~4%, above solids content is 20%~55%, and all the other 80%~45% are water.A nylon monomer factory that produces 50000 tons per year will discharge such waste lye 3~50,000 ton every year.COD in this waste lye is up to 30 * 10
4~60 * 10
4Mg/L.Promptly a nylon monomer factory that produces 50000 tons per year with about 20,000 tons of the annual COD that discharges of the form of waste lye, is source of pollution maximum in the nylon production technique.
In decades, domestic and international treatment process to waste lye mainly contains: burning method, neutralisation, wet oxidation process and activated sludge biochemical facture.Burning method is present topmost treatment process, it has absorbed the experience and the technology of black liquid incinerator, and the waste lye evaporation concentration when solid content is 50% left and right sides, is sprayed into incinerator and burns, in order to keep high temperature and burning fully, spray into some oil fuel simultaneously and carry out the cofiring burning.Burning method can be removed COD than more completely, also can reclaim a part of byproduct steam and yellow soda ash, but investment cost of burning method is big, needing a large amount of oil fuel to carry out cofiring burns, the combustion tail gas ground caustic that wafts easily, the green liquor of incinerator will cause secondary pollution inevitably, so burning method is not a kind of best spent lye treatment method.Neutralisation also is a kind of spent lye treatment method commonly used, the clear 47-35412 of Japanese Patent, clear 47-35413 discloses with in the sulfuric acid and the treatment process of waste lye, this method is after neutralization, isolate black acid liquid, use MIBK organic solvent extraction saltcake waters such as (methyl iso-butyl ketone (MIBK)) again, reclaim hexanodioic acid and low carbon acid, refining back further hydrogenating reduction becomes hexylene glycol.This method has been avoided the waste of organic resource in oil fuel and the waste lye, but this method complex process, and cost height, MIBK extraction agent are difficult to obtain.Someone adopts pimelinketone, hexalin or octanol is extraction agent, and effect of extracting is poor, and extraction agent is difficult to reclaim, and the COD clearance is low, and the cost height can't industrialization.Recyclable part steam of wet oxidation process and acetate, but will under High Temperature High Pressure, carry out, equipment material requires high, and manufacture difficulty is big, once invests highly, and the waste water raffinate COD after the processing is also high, does not see the report that big industrial production adopts.The activated sludge biochemical facture, equipment scale is big, and the cost height more is not the good method of spent lye treatment, the further deep treatment method after can only handling as the waste lye neutralisation.
<three〉summary of the invention:
The object of the present invention is to provide a kind of cyclohexane oxidation decompose in and the improving one's methods of saponification waste lye neutralizing treatment method, this method need not expensive extraction agent, utilize newly-generated organic acid dirty oil extraction to return the hexanodioic acid and the low carbon acid of aqueous phase, guaranteed the purity of by-product inorganic acid salt; Especially water is neutralized with alkali is counter, and the water vapor that in the concentration and evaporation process, steams with buck or waste lye washing, make the COD content of discharging in the condensed water very low.
<four〉description of drawings:
Accompanying drawing one: be the concentration and evaporation testing apparatus of saltcake water.
Accompanying drawing two: 1, the waste lye inlet pipe, 2, washing tower, 3, static mixer, 4, neutralization reactor, 5, the sulfuric acid inlet pipe, 6, pump is stirred in circulation, 7, water cooler, 8, separator, 9, organic acid dirty oil outlet pipe, 10, anti-neutralizing well, 11, pump, 12, the evaporating, concentrating and crystallizing device, 13, the heating steam inlet pipe, 14, the vapor condensation water outlet pipe, 15, washing tower, 16, the alkali aqueous solution inlet pipe, 17, condenser, 18, the condensed water outlet pipe, 19, the washing water return line, 20, the condensed water medial launder, 21, pump, 22, pump, 23, centrifuge separator, 24, moisture eliminator, 25, Na
2SO
4Vent pipe, 27, saltcake jellyfish liquid circulation tube, 28, Na
2SO
4The crystallization transfer lime, 29, the hot-air inlets pipe, 30, the warm air vent pipe.
Accompanying drawing three: 1, the waste lye inlet pipe, 2, washing tower, 3, static mixer, 4, neutralization reactor, 5, the sulfuric acid inlet pipe, 6, pump is stirred in circulation, 7, water cooler, 8, separator, 9, organic acid dirty oil outlet pipe, 10, anti-neutralizing well, 11, pump, 12, the evaporating, concentrating and crystallizing device, 13, the heating steam inlet pipe, 14, the vapor condensation water outlet pipe, 15, steam pipe, 16, the alkali aqueous solution inlet pipe, 17, condenser, 18, the condensed water outlet pipe, 19, the washing water return line, 20, the condensed water medial launder, 21, pump, 22, pump, 23, centrifuge separator, 24, moisture eliminator, 25, Na
2SO
4Vent pipe, 26, the hot-air inlets pipe, 27, the warm air vent pipe, 28, saltcake jellyfish liquid circulation tube.
<five〉embodiment:
The objective of the invention is to realize by following technical solution:
In neutralization reactor, it is 2~3 that waste lye is neutralized to pH value with mineral acid, and mineral acid can be a sulfuric acid, and hydrochloric acid or nitric acid are for example used 30%~98% H
2SO
4It is 2~3 that solution is neutralized to pH value, guaranteeing under the non-crystallizable temperature of separating out and concentration conditions of sodium sulfate, promptly controlling the neutralization reaction temperature is 35~70 ℃, normal pressure, standing separation goes out upper strata organic acid dirty oil phase, and the residence time of standing demix is 10 minutes to 10 hours, and temperature is 35 ℃~70 ℃ during separation, obtain lower floor's saltcake water, this water contains 20%~29% Na
2SO
4, returning the continuous circulation of water according to evaporation concentration, COD is from 5 * 10
4Mg/L~10 * 10
4Mg/L progressively is increased to 8 * 10
4Mg/L~13 * 10
4Mg/L, and be stabilized in this level.NaOH with 10%~30% or Na
2CO
3Counter this saltcake water that neutralizes of the aqueous solution makes its pH value rise to 4~7 from 2~3, to avoid corroding evaporating, concentrating and crystallizing equipment.When carrying out evaporating, concentrating and crystallizing, controlled temperature is 80 ℃~150 ℃, and absolute pressure is 0.05Mpa~1.0Mpa, concentrates back inorganic acid salt solid crystal and accounts for 20~40% of concentrated mother liquor; The water vapor that evaporates contains low carbon acid, with NaOH or the Na of a small amount of 1mol/L~6mol/L
2CO
3The aqueous solution or waste lye washing, remove low carbon acid, again by washing, be condensed into condensed water then, the COD content in this condensed water is less than 1000mg/L, and the COD content during general normal running in the condensed water is between 100mg/L to 500mg/L, according to analysis, learn the hexanaphthene that contains in this condensed water below 5/10000ths, pimelinketone, hexalin etc., this condensed water can be returned in the cyclohexane oxidation art production process, does secondary saponification washing and joins the alkali diluting water.The lowest COD value of this condensed water, evidence are 34mg/L.Contain 20%~40% anhydrous Na in the evaporating, concentrating and crystallizing still liquid
2SO
4, reclaim anhydrous Na through centrifugal drying
2SO
4Mother liquor contains COD about 30 * 10
4Mg/L to 50 * 10
4Mg/L returns neutralization reactor, utilizes newly-generated organic acid dirty oil to extract the hexanodioic acid and the low carbon acid of this aqueous phase, makes its COD drop to 7 * 10 again
4Mg/L to 13 * 10
4Mg/L goes the concentration and evaporation operation again.
The invention is characterized in: waste lye with mineral acid neutralize, after the metathesis, the pH value of control reaction end is between 2~3, standing separation, isolate upper strata organic acid dirty oil mutually after, lower floor's water neutralizes with buck is counter, makes its pH value rise to 4~7 from 2~3, especially during the water evaporating, concentrating and crystallizing, the water vapor that steams drops to below the 1000mg/L COD of the water recovery water that steams with buck or waste lye washing; Evaporating, concentrating and crystallizing liquid is through centrifugal drying simultaneously, after isolating inorganic acid salt, mother liquor returns neutralization reactor, utilize newly-generated organic acid dirty oil to extract hexanodioic acid and low carbon acid in this circulating mother liquor, guaranteed that aqueous phase COD value can not accumulate, thereby guaranteed the quality of inorganic acid salt and the cleaning of evaporation and condensation water.
Compared with prior art, the present invention has following obvious advantage:
1, do not use expensive extraction agents such as methyl iso-butyl ketone (MIBK), pimelinketone, hexalin, octanol, reduced the salkali waste processing cost.
2, the hexanodioic acid and the low carbon acid of the organic acid dirty oil extraction cycle saltcake aqueous phase that generates with this technology self have guaranteed the quality of inorganic acid salt.
3, needn't reclaim extraction agent, simplify technology, reduce plant investment, simplify operation simultaneously, technology is grasped easily.
4, the condensed water COD value that steams is less than 1000mg/L, and salkali waste COD value clearance is greater than 99%.
5, the low carbon acid content in the organic acid dirty oil raises, and helps the comprehensive utilization of organic acid dirty oil, has improved its economic worth.
6, can adopt the multiple-effect concentration and evaporation, reduce the consumption of steam.Realize the industrialization continuous production easily.
Below by specific embodiment, the invention will be further described:
Embodiment 1:
In the beaker of 1000ml, add the suction filtration mother liquor 280ml of last consignment of material, add the 500ml waste lye again, this waste lye solid contents is 30%, all the other 70% are water; Being acidified to pH value with the aqueous sulfuric acid of concentration 80% is 2.2, H
2SO
4The aqueous solution slowly adds under strong mixing in the beaker, and CO is arranged this moment
2Emit, adding speed will avoid foam to overflow.Consume 80%H altogether
2SO
4The aqueous solution 130 grams, standing demix separates, and obtains upper strata organic acid dirty oil 110 grams mutually, lower floor's saltcake water 980 gram, wherein Na
2SO
4Content is 26%, and COD is 12 * 10
4Mg/L.It is 6.0 that this 980 gram water is restrained 30% the anti-pH value that is neutralized to of the NaOH aqueous solution with 20, pour at the bottom of the 1000ml garden and carry out the clean crystalline substance of evaporation concentration in the there-necked flask,, washing column and condenser are housed on the there-necked flask with the heating of 1KW electric furnace, and thermometer and nitrogen stirring, as accompanying drawing 1.The boiling back slowly drips the NaOH aqueous solution 20ml of 4mol/L above washing column, the water vapor that washing steams is removed wherein contained acidic substance, and the water vapor that steams then is condensed into condensed water in condenser, collect condensed water 460 grams, this condensed water successively is divided into two parts to collect.The COD values of preceding a 260 gram water are 600mg/L, contain a small amount of hexanaphthene, pimelinketone, hexalin through stratographic analysis; The COD value of a 200 gram water in back is 34mg/L.Under 60 ℃, contain anhydrous Na in the there-necked flask at the bottom of to the garden with B
2SO
4Liquid carries out vacuum filtration, Na at the bottom of the crystalline
2SO
4Crystallization small amount of thermal water washing, oven dry obtains white anhydrous Na then
2SO
4140 grams.Mother liquor 280ml behind the suction filtration (contains Na
2SO
431%, COD value 34 * 10
4Mg/L) return in the 1000ml beaker, do the neutralization reaction mother liquor of next batch of material.
Embodiment 2:(synoptic diagram is seen accompanying drawing 2)
During moisture 68% cyclohexane oxidation decomposes and saponification waste lye add washing tower 2 from pipeline 1 with the flow of 5.88t/h, to remove the low carbon acid (formic acid, acetate etc.) in the 130Kg/hCO2 gas of emitting in the neutralization reactor 4, the circulation saltcake jellyfish liquid of material that comes out in the waste lye at 2 ends of washing tower and 4 ends of neutralization reactor and pipeline 27 together enters circulation and stirs pump 6, after supercooler 7 and from the 98%H of pipeline 5
2SO
41.12t/h neutralization and replacement(metathesis)reaction take place in static mixer, enter neutralization reactor 4 then, neutralization reactor 4 is a normal pressure, and pH value is 2.4, regulates the cooling water inflow of water cooler 7, and the temperature of control neutralization reactor is 60 ℃.The material adverse current of neutralization reactor 4 is to separator 8, and upper strata organic acid dirty oil flows out from pipeline 9, and discharge is 1.30t/h, acts as a fuel or the raw material of highly processed goods.The saltcake water of separator 8 lower floors, adverse current is to the anti-neutralizing well 10 of saltcake water, the alkali lye 0.55t/h that contains 10%NaOH and 3% low-carbonate that gets off from washing tower 15 tower stills also flows into anti-neutralizing well 10, make its pH value rise to 5~7, the material of anti-neutralizing well 10 is squeezed into evaporating, concentrating and crystallizing device 12 by pump 11, in evaporating, concentrating and crystallizing device 12, heat with low-pressure steam, the 18%NaOH aqueous solution 0.32t/h spray washing that the water vapor that steams is sent here through piping 16 in washing tower 15 (changing the flow may command condensed water COD value of alkali aqueous solution), again through the 0.2t/h of piping 19 water washing, water vapor after the washing is condensed into condensed water in condenser 17, flow into condensed water medial launder 20, through pump 21, a part of 0.2t/h wherein goes scrubber overhead through piping 19, and 4.29t/h discharges salkali waste through piping 18 and handles workshop section in addition.This condensed water COD value is 300mg/L, can return in the cyclohexane oxidation decomposition to recycle with saponifying process.Evaporating, concentrating and crystallizing device 12 bottom materials are squeezed into centrifuge separator 23 by pump 22, and isolated 2.94t/h circulation saltcake jellyfish liquid flows back to neutralization reactor 4 by pipeline 27, and the COD value of this circulation saltcake jellyfish liquid is 40 * 10
4Mg/L; Centrifuge separator 23 isolated Na
2SO
4Crystallization enters moisture eliminator 24 through transfer lime 28, and warm air is from pipeline 29 process moisture eliminator 24 15 emptyings from pipeline 30 to washing tower.Obtain anhydrous Na from moisture eliminator 24 vent pipes 25
2SO
41.6t/h.
Embodiment 3:(synoptic diagram is seen accompanying drawing 3)
During moisture 68% cyclohexane oxidation decomposes and saponification waste lye add washing tower 2 from pipeline 1 with the flow of 5.88t/h, with remove from and low carbon acid (formic acid, acetate etc.) in the gas of reactor 4 and evaporating, concentrating and crystallizing device 12.The circulation saltcake jellyfish liquid of material that comes out in the waste lye at 2 ends of washing tower and 4 ends of neutralization reactor and pipeline 28 together enters circulation and stirs pump 6, after supercooler 7 and from the 98%H of pipeline 5
2SO
41.1t/h neutralization and replacement(metathesis)reaction take place in static mixer 3, enter neutralization reactor 4 then, neutralization reactor 4 is a normal pressure, and pH value is 2.4, regulates the cooling water inflow of water cooler 7, and the temperature of control neutralization reactor 4 is 60 ℃.The material adverse current of neutralization reactor 4 is to separator 8, and upper strata organic acid dirty oil flows out from pipeline 9, and discharge is 1.30t/h, acts as a fuel or the raw material of highly processed goods.The saltcake water of separator 8 lower floors, adverse current is to the anti-neutralizing well 10 of saltcake water, neutralize from pipeline 16 usefulness 30%NaOH solution, make its pH value rise to 4~6, the material of anti-neutralizing well 10 is squeezed into evaporating, concentrating and crystallizing device 12 by pump 11, with the low-pressure steam heating, the water vapor that steams arrives washing tower 2 through piping 15 in evaporating, concentrating and crystallizing device 12.After gas in neutralization reactor 4 and the evaporating, concentrating and crystallizing device 12 washed by washing tower 2 usefulness salkali waste, by the 0.2t/h water washing of pipeline 19, the water vapor after the washing was condensed into condensed water in condenser 17 again, the noncondensable gas emptying.Condensed water flows into condensed water medial launder 20, and through pump 21, a part of 0.2t/h wherein goes to washing tower 2 tops through piping 19, and 4.29t/h discharges salkali waste through piping 18 and handles workshop section in addition.This condensed water COD value is 300mg/L, can return in the cyclohexane oxidation decomposition to recycle with saponifying process.Evaporating, concentrating and crystallizing device 12 bottom materials are squeezed into centrifuge separator 23 by pump 22, and isolated 2.94t/h circulation saltcake jellyfish liquid flows back to neutralization reactor 4 by pipeline 28, and the COD value of this circulation saltcake jellyfish liquid is 40 * 10
4Mg/L; Centrifuge separator 23 isolated Na
2SO
4Crystallization enters moisture eliminator 24, and warm air 2 washes with water from pipeline 27 to washing tower through moisture eliminators 24 from pipeline 26.Obtain anhydrous Na from moisture eliminator 24 vent pipes 25
2SO
41.58t/h.The aspect that this embodiment is better than embodiment two is: directly utilize waste lye to wash the water vapor that contains low carbon acid, reduced the consumption of bronsted lowry acids and bases bronsted lowry in industrial production, and the COD value of condensed water still remains on very low level.