Production system for improving yield of phosphoric acid in semi-hydrated-dihydrated process

Abstract

The utility model discloses a production system for improving the yield of phosphoric acid in a semi-hydrated-dihydrated process, which comprises a 1 # premixing tank (1), a 2 # premixing tank (2), a 1 # dissolving tank (3), a 2 # dissolving tank (4), a 1 # crystallization tank (5), a 2 # crystallization tank (6) and a flash cooling system (7) which are sequentially arranged and communicated through pipelines, and also comprises a defoaming system (8) arranged on the 2 # crystallization tank, the defoaming system comprises a demister (81) and a defoaming fan (82), the demister (81) and the defoaming fan (82) are sequentially communicated with the 2 # crystallization tank through pipelines, the defoaming fan (82) is connected with a gas phase outlet of the demister, an outlet of the defoaming fan (82) is communicated with the 2 # crystallization tank, and a liquid phase outlet of the demister is communicated with the 2 # crystallization tank through a liquid seal tank (83) of the demister. The device effectively avoids the problem that the input amount of phosphorite powder is reduced due to the fact that phosphorite is decomposed by concentrated sulfuric acid and a large amount of gas is generated due to high carbonate content, improves the yield of semi-hydrated-dihydrated process phosphoric acid, and guarantees safe and stable operation of the whole production system.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of wet-process phosphoric acid production technology, especially relates to a production system for improving the yield of semi-water-dihydrate process phosphoric acid. BACKGROUND

[0002] In the production process of semi-water-dihydrate process phosphoric acid, phosphate rock and returned dilute phosphoric acid enter 1# premix tank-2# premix tank-1# dissolution tank-2# dissolution tank-1# crystallization tank-2# crystallization tank, and tail gas is washed by a semi-water tail suction horizontal washing tower, the gas phase of 2# crystallization tank enters a semi-water high-level flash cooler through a flash slurry pump, the gas phase enters a flash defoaming device, and the liquid phase enters 1# crystallization tank through a semi-water flash evaporation discharge liquid seal tank.

[0003] Generally, the semi-water-dihydrate process phosphoric acid is produced by using phosphate rock as raw material, and the phosphate rock is rich in carbonate, especially the imported phosphate rock, which is high in calcium salt content. After the reaction and decomposition of phosphate rock and phosphoric acid in the return slurry, fluorine exists in the form of hydrogen fluoride (HF) and silicon tetrafluoride (SiF4) in steam, and exists in the form of fluorosilicic acid (H2SiF6) and fluorosilicate in the phosphoric acid liquid phase. Hydrogen fluoride enters the tail gas absorption system, but the decomposition of phosphate rock by concentrated sulfuric acid and the large amount of carbon dioxide generated due to the high content of carbonate will cause overflow, resulting in a decrease in the addition amount of phosphate rock powder and affecting the efficient operation of the entire production system, thereby reducing the yield of wet-process phosphoric acid. Moreover, the large amount of hot gas generated during feeding will also cause safety hazards. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at solving the deficiency of prior art, and provides a production system for improving the yield of semi-water-dihydrate process phosphoric acid by setting a defoaming system on the crystallization tank to increase the feeding amount.

[0005] The technical scheme adopted by the utility model is as follows:

[0006] The utility model discloses a production system for improving the yield of semi-water-dihydrate process phosphoric acid, which comprises 1# premix tank, 2# premix tank, 1# dissolution tank, 2# dissolution tank, 1# crystallization tank, 2# crystallization tank and a flash cooling system which are sequentially arranged and connected by pipelines.

[0007] The flash cooling system comprises a flash slurry pump, a semi-water high-level flash cooler, a flash defoaming device and a flash defoaming device liquid seal tank which are sequentially connected to the 2# crystallization tank by pipelines, the outlet of the flash defoaming device liquid seal tank is communicated with the 1# crystallization tank, and the outlet of the semi-water high-level flash cooler is communicated with the 1# crystallization tank through a semi-water flash evaporation discharge liquid seal tank.

[0008] The defoaming system comprises a defoaming device communicated with the 2# crystallization tank in sequence through a pipeline, a defoaming fan connected with a gas phase outlet of the defoaming device, and an outlet of the defoaming fan communicated with the 2# crystallization tank.

[0009] Further, the 1# dissolving tank is communicated with the 2# crystallization tank through a pipeline, and a circulating slurry pump is arranged on the pipeline.

[0010] The present application has the following beneficial effects:

[0011] The defoaming system is arranged on the crystallization tank in the existing semi-water-two-water process phosphoric acid production process, liquid phase flows into the crystallization tank by gravity, and gas phase enters the crystallization tank after being cooled by the defoaming fan, so that the problem of reducing the input amount of phosphate rock due to decomposition of concentrated sulfuric acid and a large amount of gas generated by high carbonate content is effectively avoided, the yield of semi-water-two-water process phosphoric acid is improved, and the safe and stable operation of the entire production system is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The present application has the following beneficial effects: DETAILED DESCRIPTION

[0013] The present application has the following beneficial effects:

[0014] As shown in the drawings, Figure 1 A production system for improving the yield of semi-water-two-water process phosphoric acid comprises 1# premixing tank 1, 2# premixing tank 2, 1# dissolving tank 3, 2# dissolving tank 4, 1# crystallization tank 5, 2# crystallization tank 6, and flash cooling system 7 arranged in sequence and communicated through pipelines, and further comprises a defoaming system 8 arranged on the 2# crystallization tank.

[0015] The flash cooling system comprises a flash cooling slurry pump 71, a semi-water high-level flash cooler 72, a flash cooling defoaming device 73, and a flash cooling defoaming device liquid seal tank 74 communicated with the 2# crystallization tank in sequence through a pipeline, wherein an outlet of the flash cooling defoaming device liquid seal tank is communicated with the 1# crystallization tank, and an outlet of the semi-water high-level flash cooler is communicated with the 1# crystallization tank through a semi-water flash evaporation discharge liquid seal tank 75.

[0016] The defoaming system comprises a defoaming device 82 communicated with the 2# crystallization tank in sequence through a pipeline, a defoaming fan 83 connected with a gas phase outlet of the defoaming device, and an outlet of the defoaming fan communicated with the 2# crystallization tank, and a liquid phase outlet of the defoaming device is communicated with the 2# crystallization tank through a defoaming device liquid seal tank 81.

[0017] The 1# dissolving tank and the 2# crystallizing tank are communicated through a pipeline, a circulating slurry pump 9 is arranged on the pipeline, under the condition of certain load, the continuous return of slurry and the stability of concentration are maintained, so as to maintain the solid content and the concentration of acid of the system, and the balance of hemihydrate and dihydrate, the solid phase content of hemihydrate slurry and the product acid concentration can be better maintained.

[0018] The utility model discloses a defoaming system is set up on the crystallizing tank, makes liquid phase through self -weight flow into the crystallizing tank, and gas phase enters the crystallizing tank after cooling through defoaming fan, effectively avoided the problem that the input of phosphorite powder is reduced because of the large amount of gas produced when concentrated sulfuric acid decomposes phosphorite because of high carbonate content, improved the output and the safety of feeding of hemihydrate-diwater process phosphoric acid.

[0019] The above-described embodiments are only used to describe the preferred modes of the utility model, and do not limit the scope of the utility model, and various deformations and improvements of the technical scheme of the utility model made by the ordinary skilled in the art without departing from the design spirit of the utility model should fall within the protection scope determined by the claim of the utility model.

Claims

1. A production system for improving the yield of phosphoric acid in a semi-hydrated-dihydrated process, comprising 1# premixing tank (1), 2# premixing tank (2), 1# dissolving tank (3), 2# dissolving tank (4), 1# crystallization tank (5), 2# crystallization tank (6), flash cooling system (7) arranged in sequence and connected by pipes, characterized in that, A defoaming system (8) is arranged on the 2# crystallization tank. The flash cooling system comprises a flash cooling slurry pump (71), a semi-water high flash cooler (72), a flash cooling defoaming device (73), and a flash cooling defoaming device liquid seal tank (74) connected with the 2# crystallization tank in sequence through pipelines. The defoaming system comprises a defoaming device (82) connected with the 2# crystallization tank through pipelines in sequence, a defoaming fan (83) connected with a gas phase outlet of the defoaming device, and a liquid phase outlet of the defoaming device connected with the 2# crystallization tank through a defoaming device liquid seal tank (81).

2. The production system for increasing the yield of phosphoric acid in a hemi-dihydrate process according to claim 1, characterized in that, The 1# dissolving tank is connected with the 2# crystallization tank through a pipeline, and a circulating slurry pump (9) is arranged on the pipeline.

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