Let’s discuss the heat exchange efficiency of methanol water coolers in different factories, as well as the methods for wax removal
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Our plant, with a capacity of 500,000 tons, uses a single-shell, double-flow heat exchanger; gas flows inside the shell. The advantages are low resistance and reduced space requirements, as well as almost no accumulation of impurities or sediment in the circulating water inside the tubes. The disadvantage is however its high cost. It has been in operation for 3 years without any problems. The wax removal method involves introducing low-pressure steam at the air inlet of the heat exchanger, while simultaneously introducing N2 at the inlet of the synthesis tower to ensure that the steam follows the correct flow path; wax is then removed at the alcohol outlet, and this process takes about 12 hours.
Datang Duolun uses dewaxing devices for dewaxing – does anyone know how these devices work?
This post was last edited by TH373637 on 2014-1-2 08:00. The methanol dewaxer is used to separate and remove wax substances before they solidify. A dewaxing unit separates gaseous methanol from liquid wax at specific temperatures and pressures, thereby completely removing paraffin from the system during the operation of the methanol production facility. It should be a somewhat more complex gas-liquid separation process; the key is to control the temperature properly. With investments of several million in pipelines and equipment, it shouldn’t be that complicated. Approximately 4 million was invested in this set of equipment at Datang Duolun.
We have an annual production capacity of 30 Wt; it uses shell-and-tube reactors with online wax removal, and the output is obtained approximately once a month
The processes are different, and the wax removal methods vary; that’s what I know； Reduce the amount of water in the water cooler directly, thereby raising its temperature and removing the wax
With online removal, how much wax can be removed? And what should be done with the crude methanol produced? We have always stopped the process for wax removal; it’s only been done once after 2 years of operation, and about a dozen bags of wax were removed. Foreign catalysts are used; it is said that domestic catalysts generally produce more wax
Online dewaxing allows for a direct reduction in the amount of water used in the water cooler, which raises the temperature at the outlet of the water cooler and thereby facilitates wax removal. However, the wax removed in this way can clog the pipes during transportation, as well as accumulate in the methanol storage tank; this may affect the operation of the methanol pump and clog its filters. . . . It is best to remove wax after the vehicle has been parked. The circulating water in the water cooler can be stopped, a blind flange can be installed on the flange of the heat exchanger in front of the water cooler, and the flange at the outlet of the water cooler can be detached; a blind flange can then be used to block the pipe opening, allowing the waxy substances to flow out from that point. Finally, low-pressure steam can be introduced into both the tube side and the shell side of the water cooler, which helps to remove the wax more thoroughly. The key is to maintain a slight positive pressure in the system when removing the blind flange, to prevent air from entering.