KR100355334B1 - Method and apparatus for recovering terephthalic acid - Google Patents
Method and apparatus for recovering terephthalic acid Download PDFInfo
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Abstract
본 발명은 더욱 고순도의 테레프탈산을 연속적으로 제조할 수 있는 테레프탈산의 회수방법을 제공하는 것이다.The present invention provides a method for recovering terephthalic acid that can continuously produce higher purity terephthalic acid.
파라크실렌을 액상 산화하여 얻어진 조테레프탈산을 완전 용해하는 온도에서 물에 용해시켜 상기 수용액을 제VIII족 금속촉매와 접촉시켜 정제하고, 상기 수용액을 플래시 증발을 사용하여 수용액중에 용해되어 있는 테레프탈산을 회수하는 데있어서, 각 결정석출조의 조작온도범위를 근사식 y = 266 exp (-0.61 x), x …1 을 총단수로 분할한 값에 각 단의 단수치를 곱한 값, y …온도(℃)에 의해 규정하여 불순물의 함유량이 적은 테레프탈산 결정을 얻는다.Paraterylene was dissolved in water at the temperature of complete dissolution of the crude terephthalic acid obtained by liquid phase oxidation. The aqueous solution was contacted with a Group VIII metal catalyst for purification, and the aqueous solution was recovered by using flash evaporation to recover the terephthalic acid dissolved in the aqueous solution. In addition, the operating temperature range of each crystallization tank is approximated by the equation y = 266 exp (-0.61 x), x. The value obtained by dividing 1 by the number of stages and the number of stages of each stage, y... It is prescribed | regulated by temperature (degreeC) and the terephthalic acid crystal with few content of impurities is obtained.
이에 따라 p-톨루일산의 양과 석출하는 테레프탈산 결정량의 밸런스가 적절하게 되도록 각 결정석출조의 온도를 설정할 수 있고, 그 결과 원하는 순도로 원하는 양의 고순도 테레프탈산을 얻을 수 있다.Thereby, the temperature of each crystallization tank can be set so that the balance of the amount of p-toluic acid and the amount of terephthalic acid crystals deposited can be set appropriately, and as a result, a desired amount of high purity terephthalic acid can be obtained with desired purity.
Description
파라크실렌의 산화에 의해 얻어지는 조테레프탈산중에는, 4-CBA, p-톨루일산 등의 불순물이 다량으로 함유되어 있어, 종래 이들을 정제한 후, 폴리에스테르의 원료로서 사용하고 있다.In the terephthalic acid obtained by the oxidation of paraxylene, impurities such as 4-CBA and p-toluic acid are contained in a large amount, and these are conventionally used as raw materials for polyester after purification.
테레프탈산의 정제방법으로서, 고온·고압하에서 조테레프탈산의 수용액을 Pd, Pt 등의 제 VIII족 금속촉매의 존재하에서 수소를 사용하여 환원처리하고, 처리된 수용액으로부터 테레프탈산의 결정을 회수하는 방법이 알려져 있다 (일본국 특공소41-l6860호 공보).As a method for purifying terephthalic acid, a method is known in which an aqueous solution of crude terephthalic acid is reduced in the presence of Group VIII metal catalysts such as Pd and Pt under hydrogen at high temperature and high pressure to recover crystals of terephthalic acid from the treated aqueous solution. (JP-A 41-l6860).
테레프탈산의 결정을 회수하는 방법으로서는, 회분식, 연속식의 방법이 알려져 있다(영국 특허제1152575호 공보).As a method for recovering the crystals of terephthalic acid, a batch method or a continuous method is known (British Patent No. 1152575).
회분식의 방법은 고순도의 테레프탈산을 생산하기 위해서는 유효하나, 테레프탈산을 다량으로 생산할 때에는 조작상 또는 경제적으로 매우 불리하다. 그 때문에 공업적으로 테레프탈산을 생산하는 경우에는 연속식의 방법을 사용하는 것이 일반적이고, 연속플래시 결정화법을 이용하여 테레프탈산 결정의 회수온도가 다음공정인 고액분리공정의 처리온도와 동일하게 될 때 까지 각각 단계적 온도의 저하로 조작되는 2개 또는 그 이상을 직렬로 접속되는 정석조를 사용하는 방법이 알려져 있다(일본국 특개소50-49248호 공보).Batch methods are effective for producing high purity terephthalic acid, but are very disadvantageous in operation or economically when producing large amounts of terephthalic acid. Therefore, in the case of industrial production of terephthalic acid, it is common to use a continuous method until the recovery temperature of the terephthalic acid crystals by the continuous flash crystallization method becomes the same as the processing temperature of the next liquid-liquid separation process. It is known to use a crystallization tank in which two or more connected in series are each operated by a stepwise decrease in temperature (Japanese Patent Laid-Open No. 50-49248).
고액분리의 방법으로서는, 결정석출조에 의해 생성된 테레프탈산의 슬러리를결정석출조의 최종온도 및 압력에 있어서 원심분리 또는 여과하는 방법이 알려져 있고, 1단째의 고액분리 리슬러리, 2단째의 고액분리의 공정을 거쳐 건조공정으로 보내져 테레프탈산을 얻는 방법이 알려져 있다(일본국 특공소47-49049호 공보).As a method of solid-liquid separation, the method of centrifugation or filtration of the slurry of the terephthalic acid produced | generated by the crystallization tank at the final temperature and pressure of a crystallization tank is known, The solid-liquid separation slurry of the 1st stage and the process of solid-liquid separation of the 2nd stage are known. A method of obtaining terephthalic acid by passing through a drying step is known (JP-A-47-49049).
또 고액분리의 방법으로서 가압하의 상태에 있어서, 세정장치부착의 여과장치를 사용하여 고순도 테레프탈산을 얻는 방법도 몇개인가 알려져 있다(일본국 특개평1-299618호 공보, 특개평5-65246호 공보, 특표평6-50646l호 공보).In addition, several methods for obtaining high-purity terephthalic acid using a filtration device with a cleaning device under a pressurized state as a method of solid-liquid separation are known (Japanese Patent Application Laid-Open No. Hei 1-299618, Japanese Patent Laid-Open No. Hei 5-65246, Japanese Patent Application Laid-Open No. 6-50646l).
수소화 정제반응에 있어서, 조테레프탈산중의 4-CBA는, 제 VIII족 금속촉매의 존재하에서 수소에 의해 대부분 p-톨루일산으로 환원된다. 그 때문에 결정석출시스템에서는 플래시냉각법을 이용하여 온도를 단계적으로 저하시켜 p-톨루일산 등의 불순물이 적은 고순도의 테레프탈산의 결정을 얻을 필요가 있다. 이때 문제가 되는 것은 테레프탈산 결정중에 공정(共晶)된다고 생각되는 p-톨루일산이며, 포화에도 이르지 않는 충분한 물이 유지되어 있음에도 불구하고 테레프탈산 결정중에 포함되어 온다.In the hydrogenation purification reaction, 4-CBA in the crude terephthalic acid is mostly reduced to p-toluic acid by hydrogen in the presence of a Group VIII metal catalyst. Therefore, in the crystal precipitation system, it is necessary to obtain a high-purity terephthalic acid crystal containing few impurities such as p-toluic acid by gradually lowering the temperature by flash cooling. The problem at this time is p-toluic acid, which is considered to be processed in the terephthalic acid crystals, and has been included in the terephthalic acid crystals even though sufficient water that does not reach saturation is maintained.
테레프탈산의 결정에 포함되는 p-톨루일산의 공정 등을 방지하여 품질적으로 만족하는 고순도 테레프탈산을 더욱 효율적으로 제조하기 위하여 각 결정석출조의 조작조건에 대하여 더욱 균형잡힌 새로운 조건이 요망되고 있다.In order to more efficiently produce high-purity terephthalic acid which is satisfactory in quality by preventing the p-toluic acid process and the like contained in the determination of terephthalic acid, new balanced conditions are required for the operation conditions of each crystallization tank.
본 발명은 테레프탈산의 제조방법 및 장치에 관한 것으로, 특히 파라크실렌의 산화반응에 의해 얻어진 조(粗)테레프탈산의 수용액을 제 VIII족 금속촉매의 존재하에서 수소를 사용하여 정제하여 고순도의 테레프탈산을 얻는 테레프탈산의 회수방법 및 장치에 관한 것이다.The present invention relates to a method and apparatus for producing terephthalic acid. In particular, an aqueous solution of crude terephthalic acid obtained by oxidation of paraxylene is purified using hydrogen in the presence of a Group VIII metal catalyst to obtain terephthalic acid of high purity. The present invention relates to a method and a device for recovering.
도 1은 본 발명에 의한 테레프탈산의 회수방법의 일 실시예를 나타내는 블록계통도이다.1 is a block diagram showing an embodiment of a method for recovering terephthalic acid according to the present invention.
〈실시예〉<Example>
실시예 1 :Example 1:
도 1에 나타내는 장치를 사용하여 고순도 테레프탈산을 제조하였다. 원료로서 사용한 조테레프탈산(CTA)중의 불순물(4-CBA, p-톨루일산 등)의 양은 테레프탈산에 대하여 약 3,000ppm-wt 이다. 이 CTA는 CTA 혼합조(1)에 있어서 이온교환수와 혼합되어 25wt% 농도의 테레프탈산 물슬러리가 된다. 혼합된 테레프탈산 물슬러리는 수용매가 증발하지 않도록 가압(약 90 kg/cm2G)하여 약 285℃까지 가열된다. 가열된 CTA 슬러리는 CTA 용해조(3)에 있어서 일시적으로 체류되어 용해의 완전화가 확보된다. 이어서 완전용해된 CTA 수용액은 시판의 Pd/C 촉매를 충전한 물첨가반응조(4)를 통과하여 CTA 수용액중의 4-CBA는 거의 전량 p-톨루일산으로 환원된다.High purity terephthalic acid was manufactured using the apparatus shown in FIG. The amount of impurities (4-CBA, p-toluic acid, etc.) in the crude terephthalic acid (CTA) used as a raw material is about 3,000 ppm-wt relative to terephthalic acid. This CTA is mixed with ion-exchange water in the CTA mixing tank 1 to become a terephthalic acid water slurry having a concentration of 25 wt%. The mixed terephthalic acid water slurry is heated to about 285 ° C. under pressure (about 90 kg / cm 2 G) to prevent evaporation of the solvent. The heated CTA slurry is temporarily retained in the CTA dissolution tank 3 to ensure complete dissolution. Subsequently, the completely dissolved CTA aqueous solution is passed through a water addition reactor 4 filled with a commercial Pd / C catalyst, and 4-CBA in the CTA aqueous solution is almost reduced to p-toluic acid.
물첨가반응 후의 테레프탈산용액은 1단째 결정석출조(5), 2단째 결정석출조 (6), 3단째 결정석출조(7), 4단째 결정석출조(8), 5단째 결정석출조(9)인 결정석출시스템의 액상부에 공급되어 압력제어에 의해 서서히 감압온도 강하되었다. 그리고 각 결정석출조의 체류시간은 20∼40분으로 하였다.After the water addition reaction, the terephthalic acid solution was subjected to the first stage crystal precipitation tank (5), the second stage crystal precipitation tank (6), the third stage crystal precipitation tank (7), the fourth stage crystal precipitation tank (8), and the fifth stage crystal precipitation tank (9). Was supplied to the liquid phase of the crystal precipitation system, and the pressure was gradually decreased by the pressure control. The residence time of each crystal precipitation tank was set to 20 to 40 minutes.
5단째 결정석출조(9)로부터 얻어진 테레프탈산을 다량으로 포함하는 테레프탈산 용액은 블록(10)에 있어서 고액분리·건조되어 최종제품인 고순도 테레프탈산이 회수된다.The terephthalic acid solution containing a large amount of terephthalic acid obtained from the fifth-stage crystal precipitation tank 9 is solid-liquid separated and dried in block 10, and high-purity terephthalic acid which is a final product is recovered.
결정석출조의 단수를 5단으로 하고, 각 결정석출조의 조작온도를 표 1과 같이 행하였을 때의 고순도 테레프탈산중의 p-톨루일산 함유량을 나타낸다.The number of stages of the crystallization tank is set to 5 stages, and the p-toluic acid content in the high purity terephthalic acid when the operation temperature of each crystallization tank is performed as shown in Table 1 is shown.
실시예 2 및 3 :Examples 2 and 3:
실시예 1의 방법에 있어서, 실시예 2는 4단째 결정석출조(8)를, 실시예 3은 3단째 결정석출조(7), 4단째 결정석출조(8)를 바이패스하여 행하였다. 각 결정석출조의 조작온도 및 회수테레프탈산중의 p-톨루일산 함유량을 표 1에 나타낸다.In the method of Example 1, Example 2 bypassed the 4th stage crystal precipitation tank 8, and Example 3 bypassed the 3rd stage crystal precipitation tank 7 and the 4th stage crystal precipitation tank 8. Table 1 shows the operation temperature of each crystallization tank and the p-toluic acid content in the recovered terephthalic acid.
비교예 1, 2 및 5 :Comparative Examples 1, 2 and 5:
실시예 1의 방법에 있어서, 각 결정석출조의 조작온도를 표 1과 같이 바꾸어 행하였다. 얻어진 회수 테레프탈산중의 p-톨루일산 함유량은 표 1에 나타내는 바와 같이 되었다.In the method of Example 1, the operation temperature of each crystal precipitation tank was changed as shown in Table 1. The p-toluic acid content in the obtained recovered terephthalic acid was as showing in Table 1.
비교예 3 :Comparative Example 3:
실시예 1의 방법에 있어서, 각 결정석출조의 액상면을 내려 체류시간을 약 5분으로 조절하여 행하였다. 결과는 표 1에 나타내는 바와 같다.In the method of Example 1, the liquid surface of each crystallization tank was lowered and the residence time was adjusted to about 5 minutes. The results are as shown in Table 1.
비교예 4 :Comparative Example 4:
실시예 1의 방법에 있어서, 각 결정석출조에 대한 공급액 송입을 기상부로 내어 행하였다. 결과는 표 1에 나타내는 바와 같다.In the method of Example 1, feed liquid supply to each crystal precipitation tank was carried out to the gas phase part. The results are as shown in Table 1.
실시예 4 :Example 4:
비교예 5의 방법에 있어서, 4단째의 결정석출조에 유지되어 있는 테레프탈산 슬러리와 동량의 이온교환수를 5단째의 결정석출조에 공급하였다. 결과는 표 1에 나타내는 바와 같다.In the method of the comparative example 5, the terephthalic acid slurry and the same amount of ion-exchange water hold | maintained in the 4th crystallization tank were supplied to the 5th crystallization tank. The results are as shown in Table 1.
비교예 6 :Comparative Example 6:
실시예 1의 방법에 있어서, CTA 혼합조에 있어서의 CTA 슬러리를 20wt%로 혼합조정하였다. 각 결정석출조의 조작온도 및 회수 테레프탈산중의 p-톨루일산 함유량을 표 1에 나타낸다.In the method of Example 1, the CTA slurry in the CTA mixing tank was mixed and adjusted to 20 wt%. Table 1 shows the operation temperature of each crystallization tank and the p-toluic acid content in the recovered terephthalic acid.
실시예 5 :Example 5:
실시예 1의 방법에 있어서, CTA 혼합조에 있어서의 CTA 슬러리를 28wt%로 혼합조정하였다. 각 결정석출조의 조작온도 및 회수 테레프탈산중의 p-톨루일산 함유량을 표 1에 나타낸다.In the method of Example 1, the CTA slurry in the CTA mixing tank was mixed and adjusted to 28 wt%. Table 1 shows the operation temperature of each crystallization tank and the p-toluic acid content in the recovered terephthalic acid.
본 발명의 목적은 고순도의 테레프탈산을 연속적으로 제조할 수 있는 테레프탈산의 회수방법을 제공하는 데 있다.It is an object of the present invention to provide a method for recovering terephthalic acid which can continuously produce high purity terephthalic acid.
본 발명의 다른 목적은 더욱 고순도의 테레프탈산을 제조할 수 있는 테레프탈산의 회수방법을 제공하는 데 있다.Another object of the present invention is to provide a method for recovering terephthalic acid, which can produce higher purity terephthalic acid.
이상의 문제점을 감안하여 본 발명에서는 농도가 22∼30 wt%의 조테레프탈산의 물슬러리를 270∼300℃로 승온하여 완전히 용해한 후, 물첨가반응하고, 반응후 테레프탈산 수용액을 3 내지 5단의 결정석출조에 순차 공급하여 각 단의 결정석출조의 조작온도를 다음의 근사식으로 표시되는 값으로 선택하여 y = 266 exp(-0. 61x) ±5 ; [x : 1 을 총단수로 분할한 값으로 각 단의 단수치를 곱한 값, y : 온도(℃)], 제 1 결정석출조의 온도를 240℃에 미치지 않는 온도로 하고 각 결정석출조의 평균 체류시간을 10∼60분으로 하고, 각 조에는 상기 체류액 상부에 대한 테레프탈산 수용액 또는 슬러리를 공급하고, 최종단의 결정석출조로부터 얻어진 슬러리를 고액분리하여 고순도의 테레프탈산을 얻는 방법이다.In view of the above problems, in the present invention, the concentration of the water slurry of the crude terephthalic acid having a concentration of 22 to 30 wt% is increased to 270 to 300 ° C., completely dissolved therein, followed by water addition reaction, and after the reaction, the terephthalic acid aqueous solution is crystallized in three to five stages. Sequentially supplied to the tanks, and the operating temperature of the crystal precipitation tanks of each stage was selected as a value expressed by the following approximation formula and y = 266 exp (-0.61x) ± 5; [x: 1 divided by the total number of stages, multiplied by the number of stages, y: temperature (° C)], the average residence time of each crystallization tank with the temperature of the first crystallization tank below 240 ° C Is 10 to 60 minutes, and each tank is supplied with an aqueous solution of terephthalic acid or a slurry to the upper portion of the holding solution, and the slurry obtained from the crystallization tank at the final stage is subjected to solid-liquid separation to obtain high purity terephthalic acid.
p-크실렌을 액상 산화하여 얻어진 조테레프탈산을 수용액중에 완전용해시키고, 이 수용액을 제 VIII족 금속촉매의 존재하에서 수소와 접촉시키는 물첨가반응에 의해 정제된다. 조테레프탈산중의 4-CBA 등의 불순물은 폴리에스테르제품의 착색원인이 되고, 또 이들 불순물은 테레프탈산의 결정에 공정되어 함유되기 쉬운 성질을 가지기 때문에, 상기 반응에서 4-CBA가 p-톨루일산으로 전화되고, 또 그외의 불순물은 수소화 분해정제된다. 그리고 물첨가 반응후의 상기 수용액은결정석출시스템에 보내진다. 결정석출시스템은 직렬로 접속된 복수단의 결정석출조로 구성되어 있고, 플래시 증발을 이용하여 고순도의 테레프탈산 결정을 얻는다. 본 발명은 이 결정석출시스템에 있어서 품질을 만족하기 위하여 각 결정석출조의 최적 조작조건을 제공하는 것이다.Zoterephthalic acid obtained by liquid phase oxidation of p-xylene is completely dissolved in an aqueous solution, and the aqueous solution is purified by a water addition reaction in which the aqueous solution is brought into contact with hydrogen in the presence of a Group VIII metal catalyst. Impurities such as 4-CBA in joterephthalic acid are the cause of coloring in polyester products, and these impurities have a property of being easily processed by the crystals of terephthalic acid, so 4-CBA is converted into p-toluic acid in the reaction. In addition, other impurities are hydrocracked and purified. The aqueous solution after the water addition reaction is sent to a crystal precipitation system. The crystal precipitation system is composed of a plurality of stages of crystal precipitation tanks connected in series and obtains high purity terephthalic acid crystals by flash evaporation. The present invention provides an optimum operating condition for each crystal precipitation tank in order to satisfy the quality in this crystal precipitation system.
이와 같은 정제법에 있어서, 22∼30wt%의 조테레프탈산 물슬러리를 완전히 용해하여 수용액으로 하기 위해서는 270∼300℃ 부근의 온도를 필요로 하고, 그리고 상기 수용액을 액형상으로 존재시키기 위해서는 상기 수용액의 증기압, 대략 물의 증기압 이상을 유지하여 수소화 정제가 행하여진다.In such a purification method, a temperature of about 270 to 300 ° C. is required in order to completely dissolve 22-30 wt% of the crude slurry of Zoterephthalic acid and to form an aqueous solution, and to maintain the aqueous solution in liquid form, the vapor pressure of the aqueous solution is required. Hydrogenation and purification are performed by maintaining the vapor pressure of water at least.
그 후, 고온·고압상태의 상기 테레프탈산 수용액으로부터 테레프탈산을 결정석출시킴에 있어서, 수소화에 의하여 환원된 p-톨루일산으로 대표되는 불순물이 공정 등으로 테레프탈산의 결정입자에 포함되어 순도저하를 일으키는 것은 상기한 특허공보 등으로부터 분명하다.Thereafter, in the crystal precipitation of terephthalic acid from the aqueous solution of terephthalic acid at high temperature and high pressure, impurities represented by p-toluic acid reduced by hydrogenation are included in the crystal grains of terephthalic acid by a process or the like to cause a decrease in purity. It is clear from one patent publication.
따라서 수소화 정제에 있어서 사용되는 농도가 22∼30wt%의 물슬러리를 사용하여 결정석출 조작에 있어서의 결정석출 조건에 대하여 여러가지로 검토한 결과, 공정등에 의해 테레프탈산 결정입자에 포함되는 p-톨루일산 등의 불순물은 액상중의 불순물 농도에 영향을 미치는 것은 물론이나, 조작으로서 온도, 즉 각 결정석출조 조작온도에 있어서의 테레프탈산의 결정석출의 비율에 가장 영향을 받아 고온에서 결정석출될수록 p-톨루일산의 함유량은 적고, 저온으로 됨에 따라 p-톨루일산의 함유량이 많아진다. 특히 140∼l50℃를 하회하면 p-톨루일산량이 비약적으로 증대하는 것도 알 수 있었다.Therefore, as a result of various studies on the crystallization conditions in the crystallization operation using water slurry having a concentration of 22 to 30 wt% in the hydrogenation purification, p-toluic acid and the like contained in the terephthalic acid crystal grains by a process or the like. Impurities not only affect the impurity concentration in the liquid phase, but are most affected by the temperature of crystallization, that is, the ratio of terephthalic acid crystallization at each crystallization tank operation temperature. The content is small and the content of p-toluic acid increases as it becomes low temperature. In particular, it was found that the amount of p-toluic acid dramatically increased when it was lower than 140-1500 degreeC.
한편, 테레프탈산의 결정석출 회수량으로부터 평가하면, 최종 결정석출조, 즉 결정석출 테레프탈산 슬러리를 고액분리하는 공정에 도입하는 조의 온도를 낮게 한 쪽이 바람직하다.On the other hand, when it evaluates from the crystal precipitation recovery amount of terephthalic acid, it is preferable to lower the temperature of the final crystallization tank, ie, the tank which introduce | transduces into a process of carrying out solid-liquid separation of a crystallization terephthalic acid slurry.
이들 온도에 있어서의 이율배반의 조작을 고려하여 3 내지 5단의 결정석출조를 사용하여 고순도로 회수율이 높은 테레프탈산을 얻기 위하여 상기 근사식에 따라 온도제어하는 것이 바람직한 경향이 있음을 발견하였다. 그리고 3∼5단의 결정석출조에서 온도제어하기 위해서는 제 1 단째의 결정석출조를 240℃ 미만으로 설정하는 것이 바람직함도 알 수 있었다.In view of the operation of yield rate at these temperatures, it has been found that it is preferable to control the temperature according to the above approximation formula in order to obtain terephthalic acid having high recovery rate with high purity using three to five stage crystallization tanks. And it turned out that it is preferable to set the 1st stage crystal precipitation tank below 240 degreeC in order to control the temperature in the 3 to 5 stage crystal precipitation tank.
또한 그외의 조작조건으로서는 각 결정석출조의 체류시간에 영향을 받으며, 최저로도 10분간은 유지할 필요가 있다. 체류시간이 10분 보다 짧으면 결정이 생장하지 않고, 또한 결정중에 포함되는 불순물량도 많아진다는 경향에 있음을 발견하였다. 그리고 체류시간을 너무 크게 하여도 큰 효과는 없으며, 장치적인 밸런스로부터 60분 정도까지가 적당할 것이다.In addition, the other operating conditions are influenced by the residence time of each crystallization tank, and it is necessary to hold it for at least 10 minutes. It has been found that when the residence time is shorter than 10 minutes, crystals do not grow and the amount of impurities contained in the crystals tends to increase. If the residence time is too large, there is no significant effect. Up to 60 minutes may be appropriate from the mechanical balance.
다음에 각 결정석출조에 대한 수용액 및 슬러리의 공급은, 각 조 체류액의 액상부에 보내어 플래시 냉각시키는 것이 중요하게 된다. 즉 플래시 냉각에 의해 테레프탈산 결정입자중에 포함시키지 않기 위해서도 발생결정을 분산, 생장시킨다. 그때 결정핵이 되는 테레프탈산 결정입자를 미리 존재시킬 필요가 있다.Next, it is important to supply the aqueous solution and the slurry to each of the crystallization tanks to be cooled to the liquid phase of each bath retention liquid. That is, the generated crystals are dispersed and grown in order not to be included in the terephthalic acid crystal grains by flash cooling. In that case, it is necessary to make the terephthalic acid crystal grain which becomes a crystal nucleus exist beforehand.
최종단의 결정석출조의 조작온도를 140∼150℃로 하고, 이 온도·압력으로 1단째의 고액분리를 행하고, 다시 재슬러리용의 물을 추가하여 조작압력을 상압까지 저하시키고, 2단째의 고액분리를 행하여 테레프탈산을 회수하는 방법이 바람직하다.The operation temperature of the crystallization tank of the final stage is 140-150 degreeC, the solid-liquid separation of 1st stage is performed by this temperature and pressure, water for reslurry is added again, operation pressure is reduced to normal pressure, and the solid solution of the 2nd stage is carried out. A method of recovering terephthalic acid by separation is preferred.
무엇인가의 이유로 최종단의 결정석출조의 조작온도를 내릴 필요가 있는 경우에는 물로 희석함으로써 테레프탈산 결정중에 포함되는 p-톨루일산 등의 불순물량을 감소시킬 수 있다. 특히 상압까지 온도를 내릴 필요가 있는 경우에는 최종단결정석출조중의 테레프탈산 슬러리와 동량 이상의 물을 보냄으로써 품질적으로 만족하는 테레프탈산을 회수할 수 있다.If for some reason it is necessary to lower the operating temperature of the crystallization tank in the final stage, the amount of impurities such as p-toluic acid contained in the terephthalic acid crystal can be reduced by dilution with water. In particular, when it is necessary to lower the temperature to atmospheric pressure, terephthalic acid that is satisfactory in quality can be recovered by sending more than the same amount of water as the terephthalic acid slurry in the final single crystal precipitation tank.
또한 상압하에서 세정장치부착의 고액분리장치와 조합시킴으로써, 고액분리장치를 1단으로 할 수 있다. 재슬러리화 및 2단째의 고액분리공정이 불필요하게 되어 1단째의 고액분리공정에 상압의 장치를 사용하는 것이 가능해지기 때문에 그 경제적 효과는 크다.Moreover, by combining with the solid-liquid separator with a washing | cleaning apparatus under normal pressure, a solid-liquid separator can be made into 1st stage. The economic effect is large because reslurrying and the solid-liquid separation process of the second stage become unnecessary, and the apparatus of normal pressure can be used for the solid-liquid separation process of the 1st stage.
이들 조작조건을 제어하면, 수소화 정제반응에 의해 얻어진 테레프탈산 수용액으로부터 고순도의 테레프탈산을 회수할 수 있다.By controlling these operating conditions, high-purity terephthalic acid can be recovered from the terephthalic acid aqueous solution obtained by the hydrogenation purification reaction.
이상 설명한 바와 같이 본 발명에 의하면, p-톨루일산의 양과 석출하는 테레프탈산 결정량과의 밸런스가 적절해지도록 각 결정석출조의 온도를 설정할 수 있고, 그 결과 소망하는 순도로 소망하는 양의 고순도 테레프탈산을 얻을 수 있다.As described above, according to the present invention, the temperature of each crystal precipitation bath can be set so that the balance between the amount of p-toluic acid and the amount of terephthalic acid crystals deposited is appropriate, and as a result, a desired amount of high purity terephthalic acid is desired with desired purity. You can get it.
Claims (6)
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03086398A JP3648372B2 (en) | 1998-02-13 | 1998-02-13 | Recovery method of terephthalic acid |
| JP10-30863 | 1998-02-13 | ||
| PCT/JP1998/004413 WO1999041225A1 (en) | 1998-02-13 | 1998-09-30 | Method and apparatus for recovering terephthalic acid |
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| KR20010040788A KR20010040788A (en) | 2001-05-15 |
| KR100355334B1 true KR100355334B1 (en) | 2002-10-12 |
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| JP (1) | JP3648372B2 (en) |
| KR (1) | KR100355334B1 (en) |
| CN (1) | CN1124252C (en) |
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| JP2005225916A (en) * | 2004-02-10 | 2005-08-25 | Fuji Xerox Co Ltd | Method for producing organic functional material, organic functional material and organic electroluminescent element using the same |
| WO2005115956A1 (en) * | 2004-05-28 | 2005-12-08 | Mitsubishi Chemical Corporation | Process for producing high-purity terephthalic acid |
| KR100883288B1 (en) * | 2004-05-28 | 2009-02-11 | 미쓰비시 가가꾸 가부시키가이샤 | Process for producing high-purity terephthalic acid |
| JP4747544B2 (en) * | 2004-09-30 | 2011-08-17 | 株式会社日立プラントテクノロジー | Method for purifying terephthalic acid |
| DE602004003722T2 (en) * | 2004-12-15 | 2007-10-04 | Saudi Basic Industries Corp. | Process for the preparation of purified terephthalic acid |
| CN101622218B (en) * | 2007-02-28 | 2013-08-07 | 株式会社日立工业设备技术 | Process for producing crude aromatic dicarboxylic acid to be fed to hydrogenation purification |
| CN101624343B (en) * | 2009-08-13 | 2012-12-19 | 中国纺织工业设计院 | Hydrogen recycling method and device of refining unit of pure terephthalic acid device |
| JP7025717B2 (en) * | 2016-09-14 | 2022-02-25 | 三菱瓦斯化学株式会社 | Manufacturing method of high-purity terephthalic acid |
| CN108623065B (en) * | 2017-03-22 | 2020-08-25 | 天华化工机械及自动化研究设计院有限公司 | Method for recycling mother liquor of PTA refining unit |
| CN112774579B (en) * | 2020-12-28 | 2023-05-30 | 南京延长反应技术研究院有限公司 | Intelligent micro-interface reaction system and method for hydrofining of crude terephthalic acid |
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| JPH08208561A (en) * | 1994-11-16 | 1996-08-13 | Mitsubishi Chem Corp | Production of terephthalic acid |
| JPH1087555A (en) * | 1996-09-17 | 1998-04-07 | Hitachi Ltd | Recovery of terephthalic acid |
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| JP3648372B2 (en) | 2005-05-18 |
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| JPH11228492A (en) | 1999-08-24 |
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