CN1032808C - Process for producing long effect urea containing hydrochinone - Google Patents

Abstract

The present invention relates to a technology for producing long acting urea containing hydrochinone, which is characterized in that a procedure that hydroquinone solid or an aqueous solution with a high concentration is added with melting or solid urea, and a sufficient mixing procedure are added in a urea synthesis technology used at present. Because after hydroquinone is added with a urea condensing and separation procedure of the urea synthesis technology in the technology, the pollution of the hydroquinone on discharged waste water in the process of producing long acting urea can be effectively avoided. In addition, the technological method has the advantages of few needed accessory devices, simple technological process and low energy consumption, is a good executive plan for improving the urea synthesis technology for producing long acting urea at present, and is easy to popularize in a chemical fertilizer industry.

Description

A kind of process for producing long effect urea that contains Resorcinol

The invention belongs to the field of urea fertilizer manufacturing process, a kind of long-acting urea fertilizer production technique that contains Resorcinol promptly is provided.

Urea fertilizer has become most important a kind of solid nitrogenous fertilizer in the world agriculture, comes compared with other nitrogenous fertilizer, and urea fertilizer has many advantages; The nitrogen content height, cost is low, and is soluble in water and be easy to handle, and is suitable for producing compound manure.In addition, it concerning some crop, can also be used as foliage application except that making base manure.Yet, using urea fertilizer and also exist some that problem to be solved is arranged, mainly is that urea fertilizer can rapid hydrolysis in soil, can cause the accumulation with ammonia of increasing of P in soil H value on the one hand, produce the murder by poisoning of nitrite and ammonia, this is particularly serious for seedling that germinates and children plant in age; Urea vapors away in a large number with gaseous form after changing ammonia on the other hand.Be the loss of the blood urea nitrogen of minimizing in being manured into soil, people taked number of ways to study controlled availability fertilizer, promptly were to make urea be unlikely hydrolysis rapidly in soil in a short time.Like this, a large amount of urea fertilizers in once being manured into soil can manage to make it to give continual and steady supply in the crop whole growing.As a kind of feasible technical solution, present inventors once proposed to add urease inhibitor in early stage and obtained a kind of long-acting urea fertilizer (Chinese patent CN85109580) in urea, promptly adopting Resorcinol is urease inhibitor, joins the long-acting urea fertilizer that obtains containing Resorcinol in urea or the urea derivative by a certain percentage.This kind fertilizer adopts present production technology of urea method, just after the urea synthesis operation of this technology, before the granulating working procedure, the Resorcinol aqueous solution that dissolving in advance is good enters in the mixing tank simultaneously with urine by a certain percentage, makes both thorough mixing evenly after granulating working procedure is made the long-acting urea fertilizer that contains Resorcinol.This method is owing to be on the basis of original urea synthesis production technique only, increased Resorcinol liquid and urine blended operation, it just sets up two mixing tanks (being the usefulness that Resorcinol liquid and urine mix), a Resorcinol liquid storage tank and two liquid pumps on the slave unit.Therefore, its embodiment is simple, is easy to use in urea industry is produced.Specifically, be that Resorcinol is used water dissolution earlier by the preferable embodiment that this technology provided, and then be added in the urea synthesis solution in proportion.Though the Resorcinol that this scheme is added can fully mix with urine, owing to Resorcinol is added to also must be in the urea synthesis system through two-stage evaporation, its phlegma contains little ammonia, CO ₂And to reclaim in the urea production process, thereby in the phlegma contained a small amount of Resorcinol also along with returning the recycle system, so in the end in Pai Fang the sewage, the content of Resorcinol is higher, existence pollution problem to a certain degree.In addition, even the Resorcinol aqueous solution is added to before the dual circulation of producing in the urea technique flow process, after separating, dual circulation still have a small amount of Resorcinol to return the recycle system, so still there is the pollution problem of discharge water.Simultaneously, another shortcoming of this processing method is to add the more Resorcinol aqueous solution, has increased the burden of urine system moisture evaporation, promptly increases energy consumption to a certain extent.

The objective of the invention is to improve the deficiency in the above-mentioned production technique, make the mixing with it that both guarantees that the Resorcinol that adds in the urea can be full and uniform, avoid in process of production Resorcinol again the pollution of discharge water.Simultaneously, further reduce the energy consumption of producing long-acting carbamide.

In the technological process of production of long-acting carbamide, after one section evaporation and the dual circulation operation, all to pass through separator, steam condensate is recovered in the recycle system, therefore be the pollution of the urease inhibitor Resorcinol effectively avoiding adding to discharge water, just Resorcinol must be added to and produce in the urea technique flow process after the dual circulation separation circuit, but, adopt simple urea and Resorcinol to carry out the mechanically mixing method and do not reach and give the phase effect for to make the few urease inhibitor of addition (Resorcinol) very evenly mix (Resorcinol weight accounts for 0.1～0.5%) with urea.The process for producing long effect urea that contains Resorcinol of the present invention is that patented technology CN85109580 is improved, still adopt the urea production process that uses at present, it is characterized in that after the urea concentrating and separating operation of this technology, make long-acting carbamide reaching thorough mixing two procedures in a certain amount of solid or higher concentration Resorcinol aqueous solution adding molten or the solid urea.Specifically, the interpolation of Resorcinol can be adopted following several embodiment in the production technique of the present invention:

1, after urea concentrating and separating operation, solid (crystallite or Powdered) Resorcinol is added in the molten urine thorough mixing enter granulating working procedure again after evenly; Also molten urea solution can be distributed sub-fraction, as above-mentioned adding solid Resorcinol thorough mixing evenly after counter again the notes in the Guyuan molten urea solution mix, then enter granulating working procedure;

The Resorcinol particulate that 2, will grind superfinely in granulating working procedure (＞200 order) is sprayed on the urea that is in the semi-melting state that just spray has come out from prilling tower with powder sprayer and drips, and makes urea granules surface attachment one deck Resorcinol finish granulating working procedure; For the production technique that adopts disc type granulating, spray drum granulating or fluid bed granulation etc., this technology that adds Resorcinol in granulating working procedure is simple and easy row, and contained Resorcinol amount is even in the long-acting carbamide of producing.In above-mentioned two kinds of embodiments, because the urea of molten state has very high dissolving power to Resorcinol, and dissolution rate is fast, is uniformly dispersed, so Resorcinol and the easy thorough mixing of urea are even;

3, the temperature that obtains afterwards with a certain amount of concentration Resorcinol aqueous solution sprinkling pelleting operation still remains on the urea cured granulate about 60 ℃, fully stirs, and drying is made long-acting carbamide.This kind adds the technology of Resorcinol, and Resorcinol aqueous solution preferred concentration is 20-50%, and its temperature should remain on 50～95 ℃.With this understanding, can guarantee that the Resorcinol aqueous solution sprays the urea granules surface and do not fold crystallization, Resorcinol and urea granules can fully be puddled evenly,, can in mixer (drum-type or disc type etc.), stir and enter drying process after puddling with Resorcinol aqueous solution spray;

When 4, the urea liquid after synthetic adopts crystallization processes, urea crystals by cylinder or ebullated bed pneumatic dryer dehydration in or after the dehydration in proportion with Resorcinol solid (crystallite or Powdered), puddle evenly, enter the melt pelletization operation then;

In above-mentioned process for producing long effect urea, also can when add Resorcinol, (or difference) ammonium salt, nitrate, phosphoric acid salt, sylvite and various trace element and agricultural chemicals or weedicide or the chemical agent and/or the adding of biological fertilizer of some amount be made the compound long-efficiency urea that contains multiple element or be exempted to intertill the multi-functional compound long-efficiency urea fertilizer of operation.Below by example and accompanying drawing the present invention is described further.

Fig. 1 is a technological process of production block diagram of the present invention.Wherein: A, urea synthesis decompose or flash distillation; B, one section the evaporation and separate; C, dual circulation (or crystallization urea) and separate; D, fusion; E, granulation; F, finished product; G1, G2 are recovery of circulatory system.1,2 is former interpolation Resorcinol scheme; 3, the present invention the 1st or 4 embodiments; 4, the 2nd embodiment; 5, the 3rd embodiment.

Fig. 2 utilizes general production of urea with full circulation of aqueous solution to adopt the present invention's the 1st embodiment to make the technological process of production synoptic diagram of long-acting carbamide.Among the figure: 1, NH ₃With CO ₂Mixing tank; 2, synthetic tower; 3, give separator; 4, middle pressure decomposition heater; 5, middle pressure separator decomposition; 6, low-pressure distillation tower; 7, low pressure decomposition heater; 8, low pressure decomposition and separation; 9, urine flash drum; 10, primary evaporator heater; 11, one section vapor seperator; 12, two-section evaporating heater, 13, dual circulation separator; 14, fusing urea and Resorcinol mixing tank; 15, Resorcinol percentage feeder; 16, the molten urea solution pump that contains Resorcinol; 17, prilling tower.Except that adding Resorcinol volume pump 15, fusing urea and Resorcinol mixing tank 14, all be former urea production technique in the above-mentioned process for producing long effect urea.It is even that Resorcinol (trace or powder) is squeezed in the fusing urea in mixing tank 14 thorough mixing by percentage feeder 15, by molten urea solution pump 16 molten contained the urine pump people prilling tower 17 of Resorcinol then.

Fig. 3 is for adopting the process for producing long effect urea schematic flow sheet of the 2nd kind of scheme of the present invention.For simplified construction Fig. 3 only illustrates and add the Resorcinol relevant technologies, other production technique is illustrated in figure 2 as general production urea technique method.Among the figure: 18, Resorcinol metering powder sprayer, 19, puddle device.Pressed powder (＞200 order) Resorcinol sprays raw material powder on little in the semi-melting urea that just sprays by metering powder sprayer 19 from prilling tower, connect after prilling tower 17 operations and puddle device 19, further Resorcinol and urea is puddled evenly.

Fig. 4 is for adopting the process for producing long effect urea schematic flow sheet of the 3rd kind of scheme of the present invention.In this technology Resorcinol is added in the finishing operation that urea synthesis produces, among the figure 20, Resorcinol metering spray thrower; 21, mixer; 22, moisture eliminator, temperature was about about 60 ℃ when urea granules flowed out from prilling tower 17, the Resorcinol aqueous solution that concentration 20-50% temperature is heated to 50～95 ℃ evenly sprays on the urea granules by spray thrower, enter then and fully puddle in the mixer 21 evenly, get the finished product long-acting carbamide after drying device 22 is done.

The production technique that contains the long-acting carbamide of Resorcinol provided by the present invention, (the general water solution total cycling method flow process among Fig. 2～Fig. 4) also is applicable to method commonly used in the urea production process at present such as hot gas cycle method, gas delivery total recycle process, slurries circulation method, gas formulation and integrated ammonia urea process, and the process for producing long effect urea that contains Resorcinol promptly provided by the present invention is easy to combine with existing various urea production process remove to be suitable for above-mentioned example.In addition, its accessory device of method provided by the present invention is few, and technical process is simple, and not only energy consumption is low can avoid the pollution of Resorcinol to sewage effluent again effectively, is that present urea synthesis technological transformation is for producing the preferable embodiment of long-acting carbamide.

Claims (4)

1. long-acting carbamide production method that contains Resorcinol, it is characterized in that in the urea synthesis production method, after the urea concentrating and separating operation, will count 0.1～0.5% (weight) Resorcinol solid or concentration with long-acting carbamide weight is that 20～50% (weight) aqueous solution adds molten or solid urea topic grain and thorough mixing and makes its product.

2. according to the described production method of claim 1, it is characterized in that it being its crystallite or Powdered Resorcinol solid to be added in the molten urine thorough mixing enter granulating working procedure again after evenly.

3. according to the described production method of claim 1, it is characterized in that in granulating working procedure＞200 purpose Resorcinol powder being sprayed on the urea that is in the semi-melting state that has just sprayed out from the granulation cat head with powder sprayer drips, make urea granules surface attachment one deck Resorcinol finish granulating working procedure.

4. according to the described production method of claim 1, it is characterized in that after granulating working procedure that the Resorcinol aqueous solution that temperature is remained on 50～95 ℃ sprays in the urea granules, fully stir that drying is made long-acting carbamide.

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