Engineering Tips

It is possible to collect the SOG as a liquid by use of an additional condenser. This allows for storage of the contaminants as a liquid, which can subsequently be used for fuel. There are capital cost and operational advantages to handling the liquid fuel.

The generally accepted optimum methanol concentration in the overheads is 50% by weight. At constant methanol removal, a product concentration of 10% methanol carries with it nine times more water vapor to incineration than a 50% methanol product would contain.

Mills have experienced a scale build-up on both sides of the heat exchanger. Fouling of the heat exchanger will result in loss of stripper efficiency. Preheaters foul more readily on the stripped condensate side of the heat transfer surfaces, and this surface should be accessible for cleaning.

Fouling of the stripping system increases at higher operating temperature and pressure.

For any given operating pressure, and any desired stripper off-gas (SOG) concentration there is fixed equilibrium temperature. Operating at the proper equilibrium temperature and pressure is necessary to control the overhead composition.

If cold condensate enters a stripping column full of steam, it can collapse the steam creating a vacuum that can buckle and dislodge the stripping trays. Avoid this condition by changing condensate feed rates very slowly.