Reactor equipment scaling for stirred reactors, has the following major effects.
1. Low production efficiency
Due to the low performance of heat exchange, resulting in an increase in reaction time. It is important to note that even a thin layer of dirt can significantly reduce the heat transfer performance.
2. Reduction in product quality
Problems such as dirt falling off the inner wall of the kettle, mixing of residues from the previous kettle, longer reaction times due to dirt adhesion and consequent formation of foreign reactants, discolouration of the product and uneven quality of the product in each kettle. Not only for small quantities of multi-species reactors, but also for continuous reactors, once such problems occur, the losses are enormous.
3. Increase in corrosion
This affects the service life of the reactor itself. The "corrosion" referred to here is the formation of a local battery effect in the gap between the dirt and the wall surface of the kettle due to the concentration of liquid, which results in the formation of pore corrosion and stress corrosion on the dirt attachment surface, thus reducing the durability of the reactor.
4. Other.
If the thermometer inserted into the reactor is fouled, this causes a delay in temperature measurement (Time Lag), which affects the overall reaction control system.
Dirt on the mechanical shaft seal in the kettle may lead to leakage of liquid from the kettle or even to the risk of gas ejection from the kettle.
Dirt in the bearings and rotating parts of the kettle can cause excessive vibration in the mixer and damage to the mechanical shaft seal, which can affect the overall safety of the production unit.
Cleaning methods for reactors
There are mainly three methods: mechanical cleaning, chemical cleaning and manual cleaning in the kettle.
1.Mechanical cleaning: High-pressure cleaning devices are used to clean the reactor walls and agitator surfaces with high-pressure water jets to break up the hard scale and remove it completely.
The principle of high-pressure water jet cleaning is to compress the water to high pressure and then release it through the nozzles installed on the kettle cleaning robot that reaches into the kettle. The pressure energy is transformed into the kinetic energy of the water and this energy is used to clean and remove the wall dirt by impacting on it. Unlike the previous two cleaning methods, high-pressure water jet cleaning is purely physical, using water as the medium, the cost is very low, but the efficiency is very high, high-pressure water cleaning time is very short, compared with the original manual removal, a year can save a large chunk of time to stop the kettle cleaning, if this time is used for production, will be able to generate considerable additional economic benefits. At the same time, the high-pressure water does not cause any damage to the inner wall of the reactor. At present, in the chemical industry, high-pressure water jet cleaning has gradually become the mainstream of cleaning methods.
2.Chemical cleaning: First of all, we should know the composition of the scale sample inside the reactor equipment, and it is better to take a sample for analysis. After determining the composition of the dirt, first do a test to select the cleaning agent and determine through the test that it will not cause corrosion to the equipment metal. The cleaning solution is then circulated through the equipment by setting up a temporary circulation device on site to wash away the dirt.
The stirring paddle and the kettle wall are first rinsed with an appropriate amount of water and drained.
Flush the reactor with solvent through the pressurised device stream.
If the cleaning effect is not achieved, add an appropriate amount of solvent to the reactor to warm up and stir the reflux until the cleaning requirement is achieved, then release the solvent.
Finally, flush the inner wall of the reaction kettle with a certain amount of solvent and release it.
3.Manually enter the kettle to remove manually: low cost is its biggest advantage, but it needs several hours of ventilation before entering the kettle, and the oxygen concentration in the kettle must be monitored at any time during the removal process, which is in danger of lack of oxygen. Cleaning the kettle by hand can also cause problems with product hygiene. Generally speaking, the time required to clean a kettle is about half a day to one day.
Mechanical cleaning does not corrode the equipment and can be effective for hard scales, but it takes a long time and is labour intensive; chemical cleaning uses less labour, has a short cleaning time and is thorough, but may cause the equipment to be corroded; manual cleaning in the kettle is low cost, but is more dangerous and cannot be cleaned completely. Therefore, chemical cleaning is used in soft and thin dirt conditions, mechanical cleaning is used in hard and thick dirt conditions.
The effect of reactor cleaning
1. Improve the cooling effect and reduce the occurrence of accidents. After the reaction kettle water jacket cleaning, remove the sludge to make the heat exchanger water jacket smooth, clear water quality, while improving the heat exchange efficiency of the reaction kettle jacket, improve the cooling effect, ensure the product process, quality and energy saving of more than 10%-30%, make the reaction kettle water jacket safe and efficient operation.
2. protect the heat exchange equipment and prolong the service life, after cleaning the reactor water jacket, it can prevent rust. Anti-scaling, to avoid corrosion of the heat exchanger, damage, put into the corrosion inhibitor after, can make the equipment corrosion speed drop 90%, so that the service life of the equipment doubled.
3. energy and water saving, reduce costs, reactor water jacket cleaning in the removal of scale, prevent the formation of scale, improve the heat exchange rate while reducing the consumption of electricity or fuel. Reactor water jacket cleaning, can improve the concentration multiplier, reduce the amount of drainage, improve the utilization rate of circulating water. 4.
4. Significant savings in maintenance costs and production downtime. Without cleaning the water jacket of the reactor, the heat exchanger pipeline will be blocked, scaling, corrosion, overpressure shutdown, or even failure and scrapping.
Source: Sohu.com
This article is reproduced on the internet and is copyrighted by the original author. If copyright is involved, please contact us and we will remove the content as soon as possible.
