[0028] The technical solutions of the present invention will be described in detail below in conjunction with embodiments.
[0029] The preparation method of H-acid with high efficiency and energy saving effect according to the embodiment of the present invention includes the following processes:
[0030] Step 10) Carry out sulfonation treatment to obtain sulfonate;
[0031] Step 20) nitrify the sulfonate obtained in step 10) to obtain a nitrate;
[0032] Step 30) Denitrify the nitrate obtained in step 20) to obtain the denitrified product;
[0033] Step 40) Perform extraction treatment on the denitrified product obtained in step 30) to obtain dilute sulfuric acid and an extraction mixture, and perform back extraction on the extraction mixture to obtain a nitro T acid solution;
[0034] Step 50) Perform reduction treatment on the nitro T acid solution obtained in step 40) to obtain an amino T acid solution;
[0035] Step 60) Concentrate the amino T acid solution and liquid caustic soda obtained in step 50) respectively to obtain concentrated amino T acid solution and liquid caustic soda;
[0036] Step 70) Alkali fusion treatment is performed on the concentrated amino T acid solution and liquid caustic obtained in step 60), and the dilution treatment is performed to obtain a diluted caustic soda;
[0037] Step 80) isolating and filtering the diluted alkali melt obtained in step 70) to obtain an H-acid filter cake;
[0038] Step 90) dry the H-acid filter cake obtained in step 80) to obtain H-acid.
[0039] In the above-mentioned embodiment, H-acid is prepared through the steps of sulfonation, nitrification, denitrification, extraction, hydrogenation reduction, concentration, alkali fusion, isolation, filtration, and drying, and the whole process is continuous. At the same time, a closed reaction is adopted to reduce the fugitive emission of exhaust gas and waste liquid.
[0040] In this embodiment, solvent extraction technology is used to replace the original salting-out process, which not only saves a large amount of neutralized ammonia, but also reduces the generation of T-acid isolation wastewater. The dilute sulfuric acid produced by extraction can also be used in the H-acid isolation process, which also reduces the amount of sulfuric acid used for H-acid isolation; this step alone can increase the yield by about 10% and save a lot of resource consumption. In this embodiment, the hydrogenation reduction cleaner production technology is used to replace iron powder reduction, and the product yield is increased by about 3%, the production of iron sludge is completely removed, and the production of iron sludge can be reduced by more than 60,000 tons per year.
[0041] In the above embodiment, as a preferred solution, the step 10) specifically includes:
[0042] Continuously add liquid naphthalene and 100% sulfuric acid solution to the sulfonation kettle, raise the temperature in the sulfonation kettle to 90°C, perform the first sulfonation, and pass the product after the first sulfonation through the buffer tank After that, it is continuously sent to the metathesis sulfonation tower, and the temperature in the metathesis sulfonation tower is raised to 150°C for metathesis reaction;
[0043] The materials completed by the metathesis reaction, the sulfuric acid solution with a mass concentration of 100% and the fuming sulfuric acid with a mass concentration of 65% are continuously fed into the sulfonation reactor. The temperature in the sulfonation reactor is 65°C, and the second time Sulfonation
[0044] The materials after the second sulfonation and 65% mass concentration of fuming sulfuric acid are sent to the tertiary sulfonation tower. The temperature in the tertiary sulfonation tower is raised to 150°C for the third sulfonation to generate sulfonates. And send the sulfonate to the sulfonate buffer tank for storage. Sulfonate is prepared for nitration treatment.
[0045] In this preferred example, step 10) is expressed as a chemical reaction formula as follows:
[0046]
[0047] In step 10), the liquid naphthalene can be prepared by the following method: solid refined naphthalene is heated and melted by steam, filtered to remove impurities, and then made into liquid naphthalene.
[0048] As a preferred solution, the step 20) specifically includes: the sulfonate obtained in step 10) and nitric acid with a mass concentration of 68% are continuously pumped into the first-stage nitration reactor, and nitrated at 40°C under cooling by cooling water , And then overflow to the secondary nitrification kettle to complete the nitration reaction, and the nitrate generated after the reaction is sent to the nitrate buffer tank for storage.
[0049] In this preferred example, step 20) is expressed by a chemical reaction formula as follows:
[0050]
[0051] As a preferred solution, the step 30) specifically includes: pumping water into the denitration reactor with a pump, and at the same time, flowing the nitrate obtained in step 20) into the denitration reactor, homogenizing the mixture of materials to generate denitrification products, after cooling , The denitrification product is sent to the denitrification buffer tank. The nitrogen oxide gas produced during the denitration reaction is condensed and absorbed with lye, such as sodium hydroxide, and discharged into the atmosphere after reaching the standard.
[0052] 2HNO 3 →HO 2 +NO+O 2 +H 2 O
[0053] NO 2 +NO+2NaOH→2NaNO 2 +H 2 O
[0054] As a preferred solution, the step 40) specifically includes: continuously pumping the denitrification product, extractant and water obtained in step 30) into the extraction reactor, and after four-stage countercurrent extraction reaction, the extraction mixture and dilute sulfuric acid are obtained; After the sulfuric acid is cooled and treated by activated carbon adsorption, it is stored in the first dilute sulfuric acid buffer tank; the extraction mixture is stripped with liquid caustic in the stripping reactor to obtain the extractant and the nitro T acid solution, and the extractant is returned to the extraction reaction In the vessel, the extraction reaction is carried out, and the nitro T acid solution is cooled and treated by activated carbon adsorption, and then sent to the nitro T acid storage tank.
[0055] In this step, TEHA is selected as the extraction agent, the molecular formula is: C 24 H 51 N. Step 40) The extraction process and the stripping process are expressed in chemical reaction formulas as follows:
[0056]
[0057] In this step, after the stripping treatment, the generated extractant is returned to the extraction reactor for extraction reaction. In this way, the quantity of extractant required in the extraction reaction process is greatly saved, so that the extractant can be reused during the continuous production of H-acid, and the cost is reduced.
[0058] As a preferred solution, the step 50) specifically includes: after preheating the catalyst, hydrogen, and nitro T acid solution, they are sent to the hydrogenation reactor, and the hydrogenation reduction reaction is performed at 170° C. and 20 MPa. After the reaction is completed , The material is cooled to 90°C with water to obtain a reaction mixture. Hot water is used for the next step of amino T acid preheating; the reaction mixture is separated by a gas-liquid separator and pressure is relieved to obtain an amino T acid solution and catalyst. The T acid solution is sent to the amino T acid storage tank; the filter system is used to recover the catalyst, and the recovered catalyst is reused in the hydrogenation reactor.
[0059] In this preferred example, as a preference, the catalyst is Raney nickel. Step 50) The chemical reaction formula is expressed as follows:
[0060]
[0061] In this step, after the material is cooled to 90°C with water, the water becomes hot water, which can be used to preheat the amino T acid in the subsequent steps. This is conducive to saving thermal energy. In addition, the filter system is used to recover the catalyst, and the recovered catalyst is reused in the hydrogenation reactor. During the continuous production of H-acid, the existing materials are fully utilized and reused, which is beneficial to reduce costs.
[0062] As a preferred solution, the step 60) specifically includes: using the hot water obtained when the material in step 50) is cooled to 90°C, preheating the amino T acid solution, condensing to a set concentration by 5-effect countercurrent, and then sending it to Concentrated T acid buffer tank;
[0063] The liquid caustic soda is concentrated by a 2-effect countercurrent to a liquid caustic with a mass concentration of 72%, and then sent to the concentrated liquid caustic buffer tank.
[0064] As a preferred solution, the step 70) specifically includes: preheating the concentrated liquid caustic soda in step 60) to 180° C. through a heat exchanger, and then sending it to the caustic melting kettle, and then mixing the methanol and the concentrated amino T acid The solutions were preheated and pumped into the caustic melting kettle. The liquid caustic soda, methanol and amino T acid solution were reacted at 200°C and 2.8MPa. After the reaction, the materials were pressed into the dilution kettle and diluted with water to obtain dilute methanol and diluted Alkali melt; condensation and recovery of the dilute methanol vaporized, the diluted alkali melt is recovered by the stripper to recover residual methanol; the dilute methanol is sent to the methanol rectification section to recover methanol, and the recovered methanol is used for the next alkali During the melting reaction; the diluted alkali melt is sent to the alkali melt buffer tank.
[0065] In this step, the dilute methanol after the reaction is recovered, and the recovered dilute methanol is used in the next alkali melting reaction. The recycling of methanol solution greatly reduces the amount of methanol required in the process of generating H-acid, which is beneficial to reducing costs.
[0066] Step 70) is expressed in chemical reaction formula as follows:
[0067]
[0068] As a preferred solution, the step 80) specifically includes:
[0069] Perform acid preparation treatment: mix the dilute sulfuric acid obtained in step 40) with sulfuric acid with a mass concentration of 98%, cool it, prepare dilute sulfuric acid with a set concentration, and send it to the second dilute sulfuric acid buffer tank;
[0070] Carry out isolation treatment: the alkali melt diluted in step 70), H-acid wash water and the dilute sulfuric acid in the second dilute sulfuric acid buffer tank are sent to the isolation tank for isolation treatment, and the generated sulfur dioxide is cooled and liquefied and recovered .
[0071] Carry out cooling and filtration treatment: the material after the separation treatment is continuously cooled to 50℃ in a cooling kettle, filtered and washed with a filter to obtain H-acid filter cake, washing water and mother liquor, and the washing water is stored in the washing water tank In, for the next isolation treatment; send the mother liquor to the wastewater treatment system.
[0072] In this step, the dilute sulfuric acid obtained in step 40) is used in this step, which improves the utilization rate of dilute sulfuric acid and helps to save costs. Step 80) is expressed in chemical reaction formula as follows:
[0073]
[0074] As a preferred solution, the step 90) specifically includes: the H-acid filter cake is dried with hot air in a rotary flash dryer, the dried tail gas is separated by a cyclone and dusted by a cloth bag before being discharged into the atmosphere; the obtained H-acid product is then Send to the subsequent packaging process.
