Recovery of propylene containing acid water severely corrode propylene recovery tank propylene recovery tanks only 3 to 6 years before doing a comprehensive inspection, can not understand the corrosion of the tank in normal times. Since propylene contains more acid water, once a corrosion perforation occurs in the body of the recovery tank, it may cause a major safety accident.
Main reform contents The transformation of 8000t/a propylene recovery system is based on the existing basic conditions of the plant, and is implemented in accordance with the principle of investment and quick effect. The main reforms are as follows.
(1) Add oil separator, water-alkaline washing tower (segment washing), circulating alkali pump and lye interstage cooler at the first-stage outlet of two sets of propylene recovery system compressors, and add water before the secondary inlet. Buffer tank (built-in screen slag removal). (2) Two sets of propylene recovery systems are combined at the secondary outlet of the compressor to increase the interstage cooler of the caustic scrubber, circulating alkali pump and lye. (3) The original 200m2 pre-condenser and 200m2 full condenser only use one (chilled water or circulating water cooling) to increase the propylene cryogenic heat exchanger.
Process before the reformation The gas coming out from the top of the tail washing tower first enters the 85m2 primary inlet cooler, and the shell side is cooled by chilled brine or primary water to condense part of the water vapor, and then intermittently drained in the water separator. After removing water, it is dedusted through the enamel filter. After a buffer tank is stabilized, it enters the first-stage gas cabinet of the propylene compressor. After the sewage is discharged, it enters the first-stage cylinder for compression. After compression, the temperature is cooled by a 35 m2 intercooler, and the cooler is cooled with water once. After passing through a 35m2 cooler, it is cooled with chilled brine or primary water. After intermediate treatment, it enters the secondary cylinder of the compressor for secondary compression, and then the oil separator is used to remove the entrained oil. The recovered high-temperature and high-pressure propylene is cooled by circulating water through a 200m2 pre-cooler, and then condensed by chilled water or circulating water through a 200m2 full condenser, condensing propylene into a liquid, and entering a propylene recovery tank for chlorination and cold steaming. Process before the transformation.
After the transformation process, the propylene from the tail washing tower is cooled by the 85m2 heat exchanger and then combined into the first-stage buffer tank, and then decompressed after being compressed by the compressor. Then, the inter-stage water-alkali washing tower is washed by one water and dilute alkali (5%), and the upper part of the tower contains a trace amount of acid water to the tail washing tower for spraying and recycling, and the bottom alkali of the tower is cooled by the interstage intercooler. Cycled by a circulating alkali pump. After washing, cooling, and slag removal, the propylene leaves the interstage water alkali washing tower and enters the secondary water buffer tank. Then, it enters the secondary inlet of the compressor. After the secondary compression of the compressor, the propylene pressure is about 1.2 MPa, and then enters the secondary outlet caustic scrubber and is washed with dilute alkali (2%). The bottom alkali is cooled by the interstage intercooler and then circulated by the pump. The propylene gas coming out from the top of the tower is cooled by a 200m2 cooler and then enters the propylene cryogenic heat exchanger. The shell-side gasification propylene to the chlorination of the sixth heat exchanger outlet as a reaction to supplement propylene, the tube propylene cooling and then to the propylene recovery tank to remove free water. Process after the transformation.
Summary of technical transformation of technical transformation effects (1) After the transformation, equipment corrosion is reduced and the number of unplanned stops is reduced. The pH value of the propylene recovery tank water sample is generally around 7.0, which eliminates the major safety hazard of recovering propylene acid-containing water to the propylene recovery tank.
(2) Reducing the consumption of propylene compressor in the recovery system due to high pressure, reducing the maintenance workload of the propylene compressor and reducing the labor intensity.
Economic Benefit Analysis In 2002, only 20 times of unplanned parking caused by corrosion of equipment such as recovery system and chlorination heat exchanger, the cost of each parking was calculated at 30,000 yuan, and the direct economic loss was 600,000 yuan. After the implementation of the transformation, other benefits are calculated as follows.
(1) Using one 328m2 cooler with chilled water or circulating water can meet the production requirements, saving 100,000 tons of chilled water per year and saving 10×1.2=12 (ten thousand yuan). (2) Before the transformation, the 200m2 heat exchanger should be updated three or four times a year, calculated according to each unit of 100,000 yuan, and the cost can be saved by about 300,000 yuan after the transformation. (3) Before the transformation, the chlorination heat exchanger needs to be updated one or two units per year, calculated according to each unit of 50,000 yuan, and the cost can be saved by about 100,000 yuan after the transformation.
The direct economic benefits total 60+12+30+10-7+10+30+80=225 (ten thousand yuan).
The existing problems of the propylene recovery system are stable after operation. Because of the energy saving and investment cost savings during construction, two sets of devices share one full condenser. If there is a failure, two sets of all stops must be stopped, which will not only affect the device. Annual production, and will cause loss of raw materials, increase labor intensity due to cleaning system materials. It is recommended to add a 200m2 full condenser. It is also recommended to recycle propylene to add a cryogenic heat exchanger before entering the recovery tank to enhance the dewatering effect.
Spanish fiberglass roof tile is a good replacement for traditional terracotta tile. The four layers are ASA coating, PVC layer, fiberglass mesh and the bottom layer of PVC. The upper part of the reinforced resin tile is selected as weather resistant engineering resin material to ensure that the resin glass fiber tile has anti-aging and bright appearance. After adopting composite coextrusion technology and forming at one time, the reinforced resin tile has various advantages compared with the same type of plastic tile in various aspects.
Lowes Roofing Panels,Fiberglass Roof Tiles,Clear Roofing Sheets,Fiberglass Roof Panels
PINGYUN INTERNATIONAL , https://www.pingyunconstruction.com