Questions regarding the initial operation of the sulfate-based alkylation unit
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As a beginner learning the *sulfuric acid method of alkylation, despite consulting various sources, many issues remain unclear. Listed below are these issues: 1. How can the cleanliness of the system be ensured before starting up an alkylation unit using the sulfuric acid method for the first time? Is the reactor going to be cleaned? 2. Is the reaction system washed during its initial startup? If washing with water is used, how can it be ensured that all the water in the system is removed, so as to prevent impacts on the acid concentration and equipment corrosion? 3. What are the main steps for the first startup of the device? Should the acid cycle be established first or the hydrocarbon cycle? 4. Is there any requirement regarding the concentration of isobutane returning from the top of the isobutane stripping tower? There are many issues; I hope the experts can offer some guidance! :handshake
In response to points 1 and 2: Before putting the device into operation, it is necessary to carry out tests for airtightness, purging, individual unit testing, combined testing, and water testing. These are very important procedures; it is recommended that the original poster study them carefully and prepare a detailed startup plan
I want to learn *it a bit! Are there any operating procedures for starting up the equipment?
It is recommended that you hire a driving team for system startup. Here’s a brief reply: 1. People must enter to carry out cleaning; 2. Try to prevent water from entering, and use nitrogen to keep blowing out any water that remains after pressurization; 3. Of course, hydrocarbon circulation should be carried out first; 4. Theoretically, the higher the concentration, the better
Thank you all for your advice! I have a question regarding the cleaning of the reaction system: is a hydrostatic test performed after the reactor is installed? If a hydrostatic test is conducted, how should the inner wall of the low-alloy steel reactor be protected after being exposed to water, and is it necessary to manually polish the inner wall? How is the replacement carried out in the system during the first start-up? Is it air～nitrogen～hydrocarbons? Why are there qualification standards for replacement?
The reactor does not require a hydrostatic test. The reactor needs to be cleaned thoroughly, and then its airtightness can be tested. Yes. After introducing nitrogen, the oxygen content is required to be 0.2%, although 0.5% is usually sufficient. Then hydrocarbons are used to displace nitrogen, with the criterion being that a high concentration of liquefied petroleum gas is expelled from the outlet.
Let me answer you: Judging from your situation, it seems to be a new installation. 1. It’s definitely necessary to maintain cleanliness; there’s mainly rust inside the reactor, as well as carbon residues left over from construction, which can be removed by targeting those areas. 2. Since it’s a sulfuric acid reactor, water should not be used. 3. It depends on the process you use. 4. The higher the concentration, the better
1. Before starting the alkylation process, all equipment that can be opened must be inspected and cleaned. After the trays are installed in the tower, the manholes should be checked; the reactor can be taken to the manufacturer for inspection, and it should not be opened after installation. Before the system is put into operation, pipeline purging, system airtightness testing, and nitrogen purging must be carried out；
2. Try to prevent water from entering the reaction system; once water gets in, it causes a lot of problems. Water that accumulates in the dead corners of the equipment and pipes cannot be removed, and acid will cause corrosion once it gets there. Remember, use nitrogen for purging wherever necessary； 3. The commissioning of the unit can follow the normal commissioning procedure: first establish a large cyclic isobutane process, and then carry out acid circulation ； 4. The concentration of circulating isobutane depends on the design parameters of your isobutane tower and the operating load; a higher concentration certainly has advantages