What are the signs of a decrease in the adsorption capacity of activated carbon in the heavy hydrocarbon removal tower of an LNG liquefaction plant?

The main signs of a decrease in the adsorption capacity of activated carbon in the heavy hydrocarbon removal tower of an LNG liquefaction plant include: an increase in the heavy hydrocarbon content at the outlet, changes in pressure difference, and a reduction in adsorption efficiency. When these conditions are observed, considering the inspection or replacement of the activated carbon is advisable. .

More directly, the adsorption time has shortened

Does changes in pressure difference refer to the pressure difference within the dehydrogenation tower during the adsorption process?

For example, with new activated carbon, a pressure difference appears after 3 months of use, and at that point it needs to be regenerated； Activated carbon that has been in use for several years may experience an increase in pressure difference after just one month of use ； You can also pay attention to the changes in the indicators after adsorption; the same principle applies here, and it is not recommended to wait until the levels exceed the limits before carrying out the regeneration of the activated carbon.

The main reasons for the decreased adsorption capacity of the activated carbon in the heavy hydrocarbon removal tower of the NG liquefaction unit include the failure to replace the activated carbon over an extended period, the accumulation of particulates and oil stains on the activated carbon, water, incomplete filling of the activated carbon, deactivation of the activated carbon due to exhaust gas temperatures exceeding 50°C, and air leakage from the activated carbon container. An analysis of the reasons for the reduced efficiency of activated carbon adsorption equipment shows that failing to replace the activated carbon over an extended period or its discoloration to a white color are among the common causes of decreased adsorption capacity. During use, activated carbon absorbs impurities such as particles, oil stains, and water; these impurities clog the pores of the activated carbon, thereby affecting its adsorption capacity. Furthermore, if the activated carbon is not fully packed, it will also result in poor adsorption performance. When the exhaust gas temperature exceeds 50°C, the activated carbon may become deactivated, thereby reducing its adsorption efficiency. Finally, air leakage from the activated carbon chamber is also an important factor, as it reduces the pressure inside the chamber and affects the adsorption efficiency of the activated carbon. In liquefied natural gas production, heavy hydrocarbon separation technology is crucial for ensuring the smooth progress of the liquefaction process. If the heavy hydrocarbon components are not completely separated, they may block the heat exchanger channels during the low-temperature liquefaction stage, causing freezing and blockages in the cryogenic tank. This, in turn, affects the liquefaction efficiency and energy consumption; in severe cases, it can even lead to the shutdown of the plant. Therefore, maintaining the good adsorption capacity of activated carbon is crucial for preventing freeze blockage and improving liquefaction efficiency.