SUMMERY OF THE UTILITY MODEL
In order to solve present waste alkali liquid and handle difficulty and with high costs shortcoming, the utility model provides an economic, high-efficient, easy operation's waste alkali liquid resourceful processing system gets rid of COD and the sodium sulfide of waste alkali liquid high concentration, output sodium thiosulfate and pH regulator.
The utility model relates to a waste lye resourceful treatment system, include through the regulation homogeneity pond, the oxidation system that the pipeline connects gradually, subside filtration system, triple effect evaporation system and crystallization refining system.
Preferably, the oxidation system comprises a primary oxidation device, a secondary oxidation device and a tertiary oxidation device which are connected in sequence;
the primary oxidation device is connected with the adjusting homogenizing tank, a catalyst feeding port is arranged on a pipeline between the primary oxidation device and the adjusting homogenizing tank, and the tertiary oxidation device is connected with the sedimentation filtering device;
and air inlets are formed in the primary oxidation device, the secondary oxidation device and the tertiary oxidation device.
Preferably, the primary oxidation device, the secondary oxidation device and the tertiary oxidation device are all aeration oxidation devices.
Preferably, the triple-effect evaporation system comprises a first-effect evaporator, a second-effect evaporator and a third-effect evaporator which are sequentially connected, the upper part of the first-effect evaporator is connected with the sedimentation filtration system, the bottom of the first-effect evaporator is connected with the upper part of the second evaporator, the bottom of the second evaporator is connected with the upper part of the third-effect evaporator, and the bottom of the third-effect evaporator is connected with the crystallization refining system;
and the lower parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are all provided with condensate outlets.
Preferably, the crystallization refining system comprises a crystallizer and a centrifuge which are connected, a liquid outlet and a solid outlet are arranged on the centrifuge, the solid outlet of the centrifuge is connected with a recrystallization refining device, the liquid outlet of the centrifuge is connected with a separation tower, an extraction liquid outlet and a separation liquid outlet are arranged on the separation tower, the extraction liquid outlet is connected with the crystallizer through a pipeline, and a refining unit is connected on the separation liquid outlet.
Preferably, the recrystallization refining device is a sodium thiosulfate recrystallization device.
Preferably, the refining unit is a lye refining device.
Preferably, the sedimentation filtering system comprises a sedimentation tank and a filtering tank which are connected, the sedimentation tank is connected with the tertiary oxidation device, the filtering tank is connected with the first effect evaporator, and sludge discharge ports are formed in the bottoms of the sedimentation tank and the filtering tank.
The utility model discloses an iron system catalyst and air oxidation to combine the air to let in the volume and make the conversion rate of sulphide can reach more than 97%, do not add other medicaments in the processing procedure, do not carry out the regulation of pH value, practice thrift the medicament use amount, reduce treatment cost.
The utility model discloses triple effect evaporation system and the evaporation that is commonly used go out the salt difference, just concentrate to saturation point, have very big help to the reduction of scale deposit jam and energy consumption, have great contribution to reducing running cost. The extraction crystallization can better ensure the purity of the sodium thiosulfate product, and the pH regulator is produced through subsequent separation, so that the method has use value.
The utility model has the advantages of simple operation, good treatment effect and low running cost.
Detailed Description
The utility model relates to a waste lye resourceful treatment system, include through the regulation homogeneity pond 2, the oxidation system 17 that the pipeline connects gradually, subside filtration system 18, triple effect evaporation system 19 and crystallization refining system 20.
The oxidation system 17 comprises a primary oxidation device 3, a secondary oxidation device 4 and a tertiary oxidation device 5 which are connected in sequence;
the primary oxidation device 3 is connected with the adjusting homogenizing tank 2, a catalyst feeding port 21 is arranged on a pipeline between the primary oxidation device 3 and the adjusting homogenizing tank 2, and the tertiary oxidation device 5 is connected with the sedimentation filtering device;
and air inlets 22 are formed in the primary oxidation device 3, the secondary oxidation device 4 and the tertiary oxidation device 5.
Preferably, the primary oxidation device 3, the secondary oxidation device 4 and the tertiary oxidation device 5 are all aeration oxidation devices.
The triple-effect evaporation system 19 comprises a first-effect evaporator 8, a second-effect evaporator 9 and a third-effect evaporator 10 which are sequentially connected, the upper part of the first-effect evaporator 8 is connected with the sedimentation filtering system 18, the bottom of the first-effect evaporator 8 is connected with the upper part of the second evaporator, the bottom of the second evaporator is connected with the upper part of the third-effect evaporator 10, and the bottom of the third-effect evaporator 10 is connected with the crystallization refining system 20;
and the lower parts of the first effect evaporator 8, the second effect evaporator 9 and the third effect evaporator 10 are all provided with condensate outlets 23.
The crystallization refining system 20 comprises a crystallizer 11 and a centrifuge 12 which are connected, wherein a liquid outlet and a solid outlet are arranged on the centrifuge 12, the solid outlet of the centrifuge 12 is connected with a recrystallization refining device 13, the liquid outlet of the centrifuge 12 is connected with a separation tower 15, an extraction liquid outlet and a separation liquid outlet are arranged on the separation tower 15, the extraction liquid outlet is connected with the crystallizer 11 through a pipeline, and a refining unit 16 is connected with the separation liquid outlet.
The recrystallization refining apparatus 13 is a sodium thiosulfate recrystallization apparatus.
The refining unit 16 is an alkali liquor refining device. Adding an organic solvent into a crystallizer 11, performing solid-liquid separation on the crystallized solid sodium thiosulfate through a centrifugal machine 12, and converting the separated sodium thiosulfate into a product sodium thiosulfate after passing through a recrystallization refining device 13. The mother liquor generated by the centrifuge 12 is heated by the separation tower 15 to remove the organic solvent, and the organic solvent is used as an extractant to return to the crystallizer 11, so that the organic solvent is ensured to be recycled. The main component of the separated mother liquor is sodium hydroxide which is refined and then converted into a pH regulator which can be applied in the water treatment industry.
The sedimentation filtering system 18 is a sedimentation tank 6 and a filtering tank 7 which are connected, the sedimentation tank 6 is connected with the tertiary oxidation device 5, the filtering tank 7 is connected with the first effect evaporator 8, and sludge discharge ports 25 are arranged at the bottoms of the sedimentation tank 6 and the filtering tank 7. The sedimentation and filtration system 18 only plays roles of sedimentation and filtration without adjusting the pH value, removes the sediment and colloid generated by the catalyst, fully retains the sodium hydroxide in the waste alkali liquor, and conveys the sludge generated by the system to the sewage for treatment.
The processed product of the waste alkali liquor 1 is only sodium thiosulfate and a pH regulator; the recycled water and the settled sludge are returned to the preposing device for use; the pH value of the acid and the alkali is not adjusted in the treatment process, so that a large amount of treatment agents are saved.
A method for recycling waste alkali liquor, a system for recycling waste alkali liquor to process waste alkali liquor, comprises the following steps:
(1) the waste alkali liquor 1 is pumped into a regulating homogenizing tank 2 for water quality homogenization;
(2) the produced water of the adjusting homogenizing pool 2 enters an oxidation system 17 through a pipeline, an iron-manganese catalyst is added from a catalyst adding port 21, and air required by oxidation is introduced into the oxidation system 17, wherein the specifically introduced air amount is as follows: 70 percent of the total amount of air required by the oxidation of the sulfide into thiosulfate in the waste alkali liquor is introduced into the primary oxidation device 3, 30 percent of the total amount of air required by the oxidation of the sulfide into the thiosulfate in the waste alkali liquor is introduced into the secondary oxidation device 4, 10 percent of the total amount of air required by the oxidation of the sulfide into the thiosulfate in the waste alkali liquor is introduced into the tertiary oxidation device 5, the addition of the catalyst is 3-5 per mill of the total weight of the waste alkali liquor, and the reaction temperature is controlled to be 50-60 ℃; the used catalyst is an iron catalyst, sodium sulfide is subjected to controlled oxidation under an alkaline condition, and an oxidation product is controlled to be sodium thiosulfate; the efficiency of converting sulfide into thiosulfate reaches 97%.
(3) The water treated by the oxidation system 17 sequentially enters a sedimentation tank 6 and a filtering tank 7, the water stays in the sedimentation tank 6 for 30-35 hours, a sludge discharge port 25 is formed in the bottom of the sedimentation tank 6, the clear liquid enters the filtering tank 7 after filter pressing, the filtering precision is controlled to be in a micron level, the subsequent triple effect evaporation system 19 is prevented from being blocked and the subsequent product purity is prevented, and the sludge generated by sedimentation and the sludge generated by filtering are discharged and then are treated separately;
(4) the water treated by the filter 7 enters a triple effect evaporation system 19 for concentration treatment, and condensate generated by the triple effect evaporation system 19 enters a reclaimed water reuse or reclaimed water unit for reuse;
(5) the water concentrated by the triple-effect evaporation system 19 enters a crystallizer 11 of a crystallization refining system 20, the temperature in the crystallizer 11 is controlled to be 40 +/-5 ℃, a solvent is added in the crystallizer 11, a solid phase produced by a centrifuge 12 is converted into a product sodium thiosulfate after passing through a recrystallization refining device 13, a bottom phase is controlled not to contain an organic solvent when a separation tower 15 carries out organic solvent analysis, the organic solvent is separated out and then returns to the crystallizer 11, and the organic solvent is supplemented appropriately according to the requirement;
the triple effect evaporation system 19 adopts a forced circulation mode, and the triple effect evaporator 10 discharges materials during saturated crystallization.
The water quality condition of the waste alkali liquor is as follows: pH is 11-13, TDS is less than 35000mg/L, and inorganic salts are mainly Na2CO3、NaOH、Na2S, wherein S2-8000mg/L of 6000-containing material, and COD is more than 10000 mg/L.
Example one
Spent lye 1 produced by certain chemical plant DMTO and DCC devices wherein: the sulfide content is 5500 mg/L, and the chemical oxygen demand COD content reaches more than 10000 mg/L.
The treatment method of the waste alkali liquor comprises the following steps:
(1) and (3) pumping the waste alkali liquor 1 into a regulating tank for water quality homogenization.
(2) The water produced by the adjusting homogenizing tank 2 enters an oxidation system 17 through a pipeline, the oxidation system 17 is only added with an iron-manganese catalyst, air required by oxidation is introduced into the oxidation system 17, 70% of the total amount of air required by oxidation of sulfide into thiosulfate in waste alkali liquor is introduced into a first-stage oxidation device 3, 30% of the total amount of air required by oxidation of sulfide into thiosulfate in waste alkali liquor is introduced into a second-stage oxidation device 4, 10% of the total amount of air required by oxidation of sulfide into thiosulfate in waste alkali liquor is introduced into a third-stage oxidation device 5, the addition amount of the catalyst is 3-5% per thousand, the reaction temperature is controlled to be 50-60 ℃, and the efficiency of converting sulfide into thiosulfate reaches 97%;
(3) the water treated by the oxidation system 17 sequentially enters a sedimentation tank 6 and a filtering tank 7, the water stays in the sedimentation tank 6 for 30-35 hours, a sludge discharge port 25 is formed in the bottom of the sedimentation tank 6, the clear liquid enters the filtering tank 7 after filter pressing, the filtering precision is controlled to be in a micron level, the subsequent triple effect evaporation system 19 is prevented from being blocked and the subsequent product purity is prevented, and the sludge generated by sedimentation and the sludge generated by filtering are discharged and then are treated separately;
(4) the water treated by the filter 7 enters a triple effect evaporation system 19 for concentration treatment, and condensate generated by the triple effect evaporation system 19 enters a reclaimed water reuse or reclaimed water unit for reuse;
(5) the water concentrated by the triple effect evaporation system 19 enters the crystallizer 11 of the crystallization refining system 20, the crystallizer 11 is realized by two measures of adding a solvent and reducing the temperature, the temperature in the crystallizer 11 is controlled to be 40 +/-5 ℃, the solvent is added in the crystallizer 11, the addition amount of the solvent is controlled to be 97 percent of the crystallization rate of the sodium thiosulfate, a solid phase produced by the centrifuge 12 is converted into a product sodium thiosulfate after passing through the recrystallization refining device 13, the purity of the solid phase produced by the centrifuge 12 after passing through the recrystallization refining device 13 is not less than 98 percent, a centrifuge mother liquor 14 produced by the centrifuge 12 enters the separation tower 15, the separation tower 15 is controlled not to contain organic solvent in the bottom phase when the organic solvent is analyzed, the organic solvent returns to the crystallizer 11 after being separated, the loss of the whole circulation is about 5 percent after the solvent is separated, and the organic solvent is supplemented properly according to the requirement.