Method for increasing yield of acetone cyanohydrin

Abstract

The invention discloses a method for increasing the yield of acetone cyanohydrin, which comprises the following steps of: performing condensation reaction on hydrocyanic acid and acetone serving as raw materials under the action of a catalyst to generate crude acetone cyanohydrin, recycling the raw materials which are not completely reacted, and refining and purifying to obtain a refined acetone cyanohydrin product. Compared with the prior art, the method has the advantages that the weight ratio of the hydrocyanic acid to the acetone is adjusted, and the incompletely reacted raw materials are sent back to the reactor to react again, so that the yield of the acetone cyanohydrin is increased.

Description

Technical Field

[0001] The invention relates to the technical field of preparing acetone cyanohydrin, and in particular to a method for increasing the yield of acetone cyanohydrin. Background Art

[0002] Acetone cyanohydrin production uses acetone and hydrocyanic acid as raw materials to condense under the action of an alkaline catalyst to generate acetone cyanohydrin, and the resulting crude acetone cyanohydrin is distilled as a finished product. At present, after distillation and purification, a portion of the acetone and hydrocyanic acid that have not been completely reacted are sent to an incinerator as waste water for incineration, resulting in a waste of raw materials and the fuel gas required for incineration. Therefore, it is necessary to develop a new method for increasing the yield of acetone cyanohydrin. Summary of the invention

[0003] Purpose of the invention: To solve the above problems, the present invention provides a method for increasing the yield of acetone cyanohydrin, by adjusting the weight ratio of raw materials and returning the unreacted raw materials to the reactor for re-reaction, thereby increasing the yield of acetone cyanohydrin.

[0004] Technical solution: To achieve the above object, the method for increasing the yield of acetone cyanohydrin according to the present invention comprises the following steps:

[0005] S1. With acetone and hydrocyanic acid as raw materials, the weight ratio of acetone and hydrocyanic acid is adjusted, and crude acetone cyanohydrin is produced by an acetone cyanohydrin reactor;

[0006] S2. The crude acetone cyanohydrin in S1 is added to an acetone cyanohydrin distillation tower for distillation and purification to produce acetone cyanohydrin and a top gas phase, and the acetone cyanohydrin is transported to a finished product tank;

[0007] S3. After the gas phase at the top of the tower in S2 is condensed, the resulting liquid phase enters the recirculating condensate tank;

[0008] S4. The uncondensed gas phase at the top of the tower enters the gas-liquid separator for separation, and the separated liquid phase enters the recirculating condensate tank;

[0009] S5. After the gas phase separated in S4 enters the vacuum pump, the liquid phase produced by condensation enters the recirculating condensate tank;

[0010] S6. The condensate in the recirculating condensate tank is transported to the acetone cyanohydrin reactor for reuse.

[0011] Furthermore, the weight ratio of acetone to hydrocyanic acid described in S1 is adjusted to 2.11:1 to 2.16:1.

[0012] Furthermore, the purity of the acetone cyanohydrin described in S2 is ≥98.5% (w / %).

[0013] Furthermore, the top gas phase described in S2 contains incompletely reacted acetone and hydrocyanic acid.

[0014] Further, the condensate described in S6 is 0.8 to 1.85 m 3 / h is all sent to the acetone cyanohydrin reactor.

[0015] Furthermore, the purity of the crude acetone cyanohydrin described in S1 is 93% (w / %).

[0016] Furthermore, the two condensations described in S3 are achieved through a first condenser and a second condenser.

[0017] Furthermore, the two condensations described in S5 are achieved by a vacuum pump and a third condenser.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: by adjusting the weight ratio of acetone and hydrocyanic acid, and collecting the incompletely reacted raw materials into a recycling condensate tank after multiple condensations, the amount of condensate in the recycling condensate tank is increased, and then the feed valve of the condensate reactor to acetone cyanohydrin is adjusted to increase the feed amount of the reactor, thereby increasing the yield of acetone cyanohydrin. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0020] The present invention discloses a method for increasing the yield of acetone cyanohydrin. Figure 1 As shown, the method for increasing the yield of acetone cyanohydrin provided by the present invention is further described in detail below: The method for increasing the yield of acetone cyanohydrin comprises the following steps: The first step: using acetone 6 and hydrocyanic acid 7 as raw materials, adjusting the weight ratio of acetone 6 to hydrocyanic acid 7 to 2.13:1, and generating crude acetone cyanohydrin with a purity of 93% (w / %) through the acetone cyanohydrin reactor 1. The second step: adding the crude acetone cyanohydrin in S1 to the acetone cyanohydrin distillation tower 2 for distillation and purification, generating acetone cyanohydrin with a purity of ≥98.5% (w / %) and a tower top gas phase, and the acetone cyanohydrin is transported to the finished product tank; wherein, the tower top gas phase contains incompletely reacted acetone and hydrocyanic acid. The third step: after the tower top gas phase in the second step is condensed twice by the first condenser 8 and the second condenser 9, the generated liquid phase enters the recycling condensate tank 4. The fourth step: the uncondensed gas phase enters the gas-liquid separator 10 for separation, and the separated liquid phase enters the recycling condensate tank 4. Step 5: After the gas phase separated in the fifth step enters the vacuum pump, the liquid phase generated by the two condensations of the vacuum pump 12 and the third condenser 11 enters the recirculating condensate tank 4. Step 6: The condensate in the recirculating condensate tank 4 passes through the recirculating condensate pump 5 and is condensed at 1m 3 / h is all delivered to the acetone cyanohydrin reactor 1 for reuse. Under the premise of ensuring the same ratio of acetone 6 and hydrocyanic acid 7, the consumption of acetone 6 is reduced. Under the same feeding conditions, according to the mass flow meter of the tower kettle of the acetone cyanohydrin distillation tower, the flow rate can be increased from 4100 to 4200 kg / h to 4200 to 4500 kg / h, thereby achieving the purpose of increasing the output of acetone cyanohydrin.

Claims

1. A method for increasing the yield of acetone cyanohydrin, characterized in that: The following steps are involved: S1. Using acetone (6) and hydrocyanic acid (7) as raw materials, adjusting the weight ratio of acetone (6) and hydrocyanic acid (7), and generating crude acetone cyanohydrin through an acetone cyanohydrin reactor (1); S2. The crude acetone cyanohydrin in S1 is added to the acetone cyanohydrin distillation column (2) for distillation and purification to produce refined acetone cyanohydrin and a top gas phase, and the acetone cyanohydrin is transported to the finished product tank (3); S3. After the gas phase at the top of the tower in S2 is condensed, the resulting liquid phase enters the recirculation condensate tank (4); S4. The uncondensed gas phase at the top of the tower enters the gas-liquid separator (10) for separation, and the separated liquid phase enters the recirculating condensate tank (4); S5. After the gas phase separated in S4 enters the vacuum pump (12), the liquid phase produced by condensation enters the recirculating condensate tank (4); S6. The condensate in the recirculating condensate tank (4) is transported to the acetone cyanohydrin reactor (1) for reuse.

2. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The weight ratio of acetone (6) to hydrocyanic acid (7) described in S1 is adjusted to 2.11:1 to 2.16:

1.

3. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The purity of the acetone cyanohydrin described in S2 is ≥98.5% (w / %).

4. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The top gas phase described in S2 contains incompletely reacted acetone and hydrocyanic acid.

5. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The condensate described in S6 is 0.8~1.85m 3 / h is all sent to the acetone cyanohydrin reactor (1).

6. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The purity of the crude acetone cyanohydrin described in S1 is 93% (w / %).

7. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The double condensation described in S3 is achieved by the first condenser (8) and the second condenser (9).

8. The method for increasing the yield of acetone cyanohydrin according to claim 1, characterized in that: The two condensations described in S5 are achieved by a vacuum pump (12) and a third condenser (11).

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