Purified terephthalic acid is white needle-like crystal or powder, which sublimes at about 300°C and has a spontaneous ignition point of 680°C. Soluble in hot ethanol, slightly soluble in water, insoluble in ether, glacial acetic acid and chloroform. Low toxicity, flammable.
Its dust and air form an explosive mixture with an explosion limit of 0.05g/L to 12.5g/L.
Purified terephthalic acid is a raw material for the production of chemical fiber products such as polyester chips, long and short polyester fibers, and other important chemical products. Purified terephthalic acid (PTA) is one of the important bulk organic raw materials, its main use is to produce polyester fiber (polyester), polyester film and polyester bottle, widely used in chemical fiber, light industry, electronics, construction All aspects of the national economy are closely related to the level of people's living standards.
At present, the equipment used in the PTA (purified terephthalic acid) industry is mainly divided into the following structures:
1. One is pressurized filtration equipment, which increases the pressure on the filter side of the mother liquor and increases the pressure difference on both sides of the filter to improve the filtration efficiency, thereby completing the filtration of PTA. The technical limitation is that the drainage in the drum is not smooth, and the filtration The pressure difference on both sides of the net is not easy to control.
2. One is a rotary drum pressurized filter. This technology is that the drum of the filter has multiple pressurized tanks. At the same time, there is a certain amount of compressed air in the pressurized chamber, which is formed by the distribution valve and the air-water separator through the atmosphere. Under the action of pressure difference, the filter cake and washing water in the tank are recovered. Its technical limitation is that the drum rotates to form a filter cake, and then washes, resulting in a high water content of the filter cake and poor regularity of the filter cake.
3. One is a filter cloth cleaning device for vacuum filters and pressurized filters. This cleaning technology is a conventional universal technology, and its limitation is: after cleaning the filter cloth, it is impossible to ensure whether the filter residue in each filter mesh is cleaned. clean. affect the filtering effect.
In response to the above problems, Wuxi ZhangHua Machinery has developed and produced a pure terephthalic acid filtration, washing and drying integrated equipment with a cylinder-cone multi-function three-in-one (invention patent number: ZL201721560677.) This machine is a cylinder-cone structure. The lower cone is equipped with a heating jacket, which can heat or cool the material. A hollow shaft and a variable-angle variable-lead hollow screw stirring device are installed inside the multi-function machine to stir and lift the material. Push out the material.
A conical filtering device with a relatively complex structure is installed in the lower cone, and a specially designed non-dead angle quick-opening discharge device or a non-dead angle pneumatic discharge ball valve is installed at the bottom of the equipment.
In the reaction stage, the reaction materials are added from the top, and the unique stirring structure can make the materials be stirred evenly in the machine, and the materials are heated or cooled simultaneously through the cylinder jacket, cone jacket, hollow shaft, and hollow spiral blade. Make the material fully react in the machine. In the filtration stage, the machine can filter and dry the material in the machine by pressurizing or vacuuming, and add washing liquid, so that the material can be automatically repulped and washed several times in the machine, and then pressed dry after meeting the washing requirements.
In the drying stage, the cylinder jacket, cone jacket, hollow shaft, and hollow ribbon heat the material at the same time and vacuumize the top, vacuum-tight and low-temperature drying of the material, and automatically seal and discharge the material after drying.
Purified terephthalic acid filtration, washing and drying integrated equipment cylinder cone multi-functional three-in-one process flow chart
The raw material p-xylene uses acetic acid as a solvent, and is oxidized into crude terephthalic acid by air under the action of a catalyst, and then crystallized, filtered, and dried to obtain a crude product; the crude terephthalic acid is hydrogenated to remove impurities, and then crystallized, Centrifugal separation and drying are PTA finished products. ?The production method is to obtain crude terephthalic acid by oxidizing p-xylene, and obtain purified terephthalic acid through beating, hydrogenation, refining, crystallization and drying.
Purified terephthalic acid filtration, washing and drying integrated equipment cylinder cone multi-functional three-in-one advantages are:
The structure is strong, the floor area is small, and the functions of PTA filtration, washing and drying are integrated, which overcomes the limitations of the existing filters in the PTA field.
Purified terephthalic acid filtration, washing and drying integrated equipment barrel-cone multi-functional three-in-one realizes continuous pressure filtration of PTA slurry, and makes the filtration, washing, drying and discharging of PTA slurry in specific different pressure area units The chambers are treated separately, and the separated dry gas after washing, PTA filter cake, PTA filtrate, and condensed gas can all be recovered separately, so as to meet the needs of industrial multi-purpose. Purified terephthalic acid filtration, washing, drying integrated equipment cylinder-cone multi-functional three-in-one small footprint, and integrate PTA filtration, washing, drying, unloading functions, economical and practical, overcome the existing filter Limitations such as bulky volume during use.
1. Closed system: The three-in-one filter, washing and drying system is a fully closed system. Production and operation in the closed system can avoid air pollution from toxic substances, and at the same time reduce the occurrence of poisoning accidents by operators.
2. Recycling: materials and solvents are almost completely recovered, avoiding waste caused by material omission and solvent volatilization, which has great economic benefits.
3. Multifunctional integrated operation: filtering, washing and drying are completed in the same equipment.
The vessel walls are equipped with heating jackets to allow drying.
4. Continuous operation: Filtration and drying are carried out in a continuous system, no need to deal with wet filter cake. The dried products can be mechanically transferred to the weighing and packaging sections.
5. Saving manpower: a non-technical person who has undergone simple training can complete the operation. Opening, closing, automatic feeding and automatic discharging do not require technical personnel to monitor.
6. Thorough cleaning: The filter, washing and drying three-in-one has the functions of automatic spraying and stirring, and the filter cake can be fully cleaned, thereby reducing the amount of sewage and reducing the cost of wastewater treatment.
7. Clean production: The multifunctional filter drying system is equipped with a dust collector to collect the dust produced after drying, which can meet the requirements of clean production.