Key points of daily operation in low-temperature methanol washing
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What are the key points in the daily operation of low-temperature methanol washing? What are the most common problems that occur during operation? What is the corresponding solution?
Focus: Maintain an optimal liquid level in each tower to ensure energy-efficient operation； Ensure that all parameters of the clean gas outlet meet the specified standards, with particular attention being paid to the CO2/H2S levels. Common problems (varies from plant to plant; analysis is based solely on our experiences): high water content in recycled methanol, and unstable quality of raw gas. Solution: (To address the above issue) Adjust the operating conditions of the thermal regeneration tower by increasing the reflux volume or the amount of steam supplied (adjusting according to the tower’s own operating conditions) ； Contact scheduling for handling. Properly adjust the liquid level for this account. Please, experts, help to complete it! !
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One more thing: it’s important that the circulation volume matches; this is very crucial. Whether during start-up, shutdown, or in response to changes, the circulation rate needs to be given attention and adjusted carefully. The principle for adjustment is to make frequent but gradual adjustments to maintain balance, avoiding large fluctuations. This post was last edited by Cancan on 2009-2-10 09:09.]
Key points for daily operation: 1. Control the temperature of each column; this is crucial for ensuring the absorption efficiency of methanol! 2. Control the water content in methanol ； 3. The control of the methanol circulation rate is also very critical
The operators are mainly responsible for maintaining the liquid level in each tower/tank, adjusting the methanol circulation rate according to fluctuations in load in order to control the levels of carbon dioxide and sulfur in the clean gas. They also ensure that the water content in methanol does not exceed specified limits (these limits vary from plant to plant). Additionally, they keep the temperature of the control system at an appropriate level. The inspectors are primarily tasked with carrying out regular inspections of the equipment
Focus on control parameters: temperature, pressure, flow rate, with process indicators as the core.
Control the liquid levels, temperatures, pressures, and H/N ratios between various towers, as well as the water content in methanol and the H2S level. During regular inspections, it is necessary to carefully check all pumps to prevent issues such as unstable circulation due to dirt clogging the filters.
1. Maintain stable liquid levels in each tower； 2. After making contact, the subsequent section shall control the system pressure properly ； 3. Stabilizing the operation of the thermal regeneration tower and the methanol-water separation tower ； 4. Large fluctuations in flow rates are strictly prohibited; when the liquid level is stable, the valve openings of the various level control valves change only slightly, which in turn keeps the flow rates through the tubes and shells of each heat exchanger stable. As a result, the variations in temperature at different points are also minimal, and thus the temperature remains stable. Therefore, to control the temperature, it is necessary to maintain stability in both the liquid level and flow rates
Pay close attention to the temperature of the process gas at the outlet, as well as the temperatures and liquid levels in each column. Also, monitor the temperatures at the outlets of the reactor column and the methanol-water separation column Be sure to adjust the steam volume to the reboiler, and also pay close attention to the reflux flow at the bottom of the absorption tower! Adjust the rough washing section position? Temperature of the exhaust gases. . . . . . . Wait
In daily production and operation, it is common for the sulfur compound levels in the purified gas to exceed acceptable limits. To prevent such excess levels, the following measures can be taken: 1. Ensure careful and proper control to coordinate the various processes before and after production, suppress the formation of organic sulfur in the gas generation units, and enhance the hydrogenation conversion of organic sulfur. 2. Strengthen the careful operation of the cooling system to minimize the temperature of methanol and facilitate the absorption of sulfides. 3. Adjust the methanol circulation rate appropriately, and adjust the liquid-to-gas ratio in a timely manner. 4. Optimize the process of methanol regeneration, particularly the CO2 desorption step. Careful handling is required for the methanol thermal regeneration system; the distribution of methanol volume in the flash system should be adjusted appropriately to maintain the optimal thermal regeneration temperature, thereby minimizing the levels of sulfides in the methanol fed into the absorption tower. 5. Regularly monitor the purity of methanol to prevent excessive accumulation of water, NH3, light oil, and organic sulfides in it, which could affect the absorption process. 6. Make timely and proper adjustments to factors such as the pressure and liquid level in the absorption tower. 7. Improve the operation of the water scrubber to ensure effective washing and minimize NH3 levels.