CN103130249A - Preparing method of crystallized sodium sulfate in liquid SO2 by means of sodium citrate - Google Patents

Abstract

The invention relates to a preparing method of crystallized sodium sulfate in liquid SO2 by means of sodium citrate. The preparing method is characterized by comprised the steps of placing crystallized sodium sulfate solution into a centrifugal machine for gravity natural filtration; spin-drying the filtered solution at a low speed of 320-380 cycles per minute for 8-12 minutes with the centrifugal machine; and carrying out washing decoloration and then spin-drying at a high speed of 780-850 cycles per minute for 12-18 minutes. The preparing method of the crystallized sodium sulfate in the liquid SO2 by means of the sodium citrate has the advantages that Na2SO4 prepared with the method is white as snow, clean and tidy, and capable of meeting the standard of high quality products; and the cost consumption problem and the environmental problem in a preparing process of the crystallized sodium sulfate in the liquid SO2 by means of the sodium citrate are solved thoroughly.

Description

Citrate Buffer is produced liquid SO 2In the sodium sulfate crystal treatment process

Technical field:

The present invention relates to the liquid SO in chemical technology field ₂Production method, particularly Citrate Buffer is produced liquid SO ₂In the sodium sulfate crystal treatment process.

Technical background:

Citrate Buffer is produced liquid SO ₂Process in, inevitably to produce SO ₄ ^2-, SO ₄ ^2-Main source is the oxidation of solution and forming, because sodium citrate solution is absorbing gaseous state SO ₂In process, produce H ₂SO ₃

H ⁺+ HSO ₃ ^-, but because of SO ₂Contain a large amount of oxygen in flue gas, thereby liquid phase oxidation reaction occurs.

2HSO ₃ ^-+O ₂→2H ⁺+2SO ₄ ^2- SO ₄ ^2-+2Na ⁺→Na ₂ ^-SO ₄

Although oxidation ratio is not high, because solution usage is more, constantly circulation contacts with furnace gas, and accumulation is got up, the SO in solution ₄ ^2-Will rise very fast, SO ₄ ^2-Also can produce the SO of trace when also having a source to be sulphur and air combustion ₃Gas and acid mist, they enter in solution also can make SO ₄ ^2-Content increases, SO ₄ ^2-Run up to that above-mentioned liquid phase oxidation reaction speed can increase severely when a certain amount of, make SO ₄ ^2-The concentration sharp increase causes solution poisoning, and specific absorption decline resolution factor is not high yet, and when serious, absorption and parsing stop, and have had a strong impact on SO ₂Production.

In former production, the SO in solution ₄ ^2-Content when being elevated to finite concentration production and can not keeping, a kind of measure is all changed solution exactly, and product cost is significantly increased.At present usually remove SO in solution with the crystallizing process under low temperature ₄ ^2-To keep the SO in solution ₄ ^2-It is low-level that content remains, keeps the solution long-period stable operation.According to the liquor analysis result, SO in solution ₄ ^2-Content during near 70g/L, just with a crystallization pump with a part of solution approximately 1/5 total amount squeeze into a crystallization kettle, still is interior carries out uniform stirring with mixing pump, passes into liquid SO in the crystallization kettle chuck ₂, liquid SO ₂Evaporation absorbs extraneous amount of heat rapidly in chuck, carries out thermal exchange with solution in still and reaches the refrigeration purpose, the SO after gasification ₂Gas is connected to the SO of system with pipeline ₂Compressor inlet, becomes liquid end product and uses or take out together by the compressor pressure-raising with gas in system after condensation.When the solution temperature in crystallization kettle drops to 2 ° of C when following, stop passing into SO ₂Sodium sulfate in solution becomes granular xln at low temperatures at this moment, the solution that will contain sodium sulfate crystal is put into a filter vat and is filtered, sodium sulfate is filtered, and other compositions in solution again send into after because of non-crystallizable being filtered and use in the lean solution groove, because this a part of solution does not contain SO ₄ ^2-So, greatly reduce the SO in total sodium citrate solution ₄ ^2-Content.Repeatable operation like this, the SO in system ₄ ^2-It is low-level that content remains, greatly promoted the life cycle of solution, also saved product cost.But this another problem occurred again, is exactly the Na after filtering ₂SO ₄Because colour difference (containing a small amount of citric acid solution) can't be utilized, the treatment process of present many producers is drained after normally with hot water, metabisulfite solution being dissolved, then is with Na ₂SO ₄Make solid waste and process, these two kinds for the treatment of processs had both increased processing cost, had polluted again environment.

Summary of the invention:

Purpose of the present invention be intended to eliminate sodium sulfate in sulphur dioxide production in processing processing costs and the problem of environmental pollution, the Citrate Buffer that provides is produced liquid SO ₂In the sodium sulfate crystal treatment process, the pollution during the sulfurous gas long period is produced reduces to zero, and has saved to a certain extent production cost.

The technical solution used in the present invention is as follows:

Citrate Buffer is produced liquid SO ₂In the sodium sulfate crystal treatment process, it is characterized in that comprising the following steps:

A, the crystalline sulfuric acid sodium solution is first put into whizzer carry out the gravity natural filtration;

Carry out low speed with whizzer again after b, filtration and dry, rotating speed 320-380 Zhuan ∕ divides, time 8-12 divides;

C, wash decolouring after drying again, carry out at last high speed drying, rotating speed 780-850 turns that ∕ divides, time 12-18 minute.

Further technical scheme is: washing decolouring after the drying described in step c, is when centrifuge speed 320-380 turns ∕ minute low speed rotation again, spray form de-mineralized water 2 minutes.

Beneficial effect of the present invention :

1, the Na that makes of the present invention ₂SO ₄Look Bai Ruxue, neat and tidy reaches the quality products standard;

2, thoroughly solve Citrate Buffer and produced liquid SO ₂In cost consumption and problem of environmental pollution.

Embodiment:

Citrate Buffer is produced liquid SO ₂In the sodium sulfate crystal treatment process, send 100kg crystalline sulfuric acid sodium solution from crystallization kettle, first put into whizzer and carried out the gravity natural filtration 30 minutes, carrying out low speed with whizzer again after filtration dries, rotating speed 350 turns that ∕ divides, 10 minutes time, and after drying, whizzer turns the ∕ timesharing at rotating speed 350, and the spray form de-mineralized water was washed decolouring in 2 minutes, carry out high speed with whizzer at last and dry, rotating speed 800 Zhuan ∕ divide, 15 minutes time.

Obtain the approximately Na of 10KG after drying ₂SO ₄, Se Bai is as snow, and neat and tidy reaches the quality products standard.

Claims (2)

1. Citrate Buffer is produced liquid SO ₂In the sodium sulfate crystal treatment process, it is characterized in that comprising the following steps:

A, the crystalline sulfuric acid sodium solution is first put into whizzer carry out the gravity natural filtration;

Carry out low speed with whizzer again after b, filtration and dry, rotating speed 320-380 Zhuan ∕ divides, time 8-12 divides;

C, wash decolouring after drying again, carry out at last high speed drying, rotating speed 780-850 turns that ∕ divides, time 12-18 minute.

2. Citrate Buffer according to claim 1 is produced liquid SO ₂In the sodium sulfate crystal treatment process, it is characterized in that: washing decolouring after the drying described in step c, is when centrifuge speed 320-380 turns ∕ minute low speed rotation again, spray form de-mineralized water 2 minutes.