a regulated forest

a regulated forest

Kết quả (Việt) 1:

một khu rừng quy định

Kết quả (Việt) 2:

Figure 6.6.2-2 is a schematic diagram of a continuous PET/TPA process, and the numbers and letters
following refer to this figure. Raw materials are brought on site and stored (1). Terephthalic acid, in powder
form, may be stored in silos. The ethylene glycol is stored in tanks. The terephthalic acid and ethylene
glycol, containing catalysts, are mixed in a tank (2) to form a paste. In the mix tank, ethylene glycol flows
into a manifold that sprays the glycol through many small slots around the periphery of the vent line. The
terephthalic acid and ethylene glycol are mixed by kneading elements working in opposite directions.
Combining these materials into a paste is a simple means of introducing them to the process, allowing more
accurate control of the feed rates to the esterification vessels. A portion of the paste is recycled to the mix
tank. This paste recycle and feed rates of TPA and ethylene glycol are used to maintain an optimum paste
density or weight percent of terephthalic acid.
The paste from the mix tanks is fed, using gear pumps to meter the flow, to a series of esterification
vessels (referred to as esterifiers, or ester exchange reactors). Two or more esterifiers may be used.
Residence time is controlled by valves in the transfer lines between each vessel. These esterifiers are closed,
pressurized reactors. Pressure and temperature operating conditions in the primary esterifier (3) are between
30 and 50 pounds per square inch gauge (psig) and 230 to 260EC (446 to 500EF), respectively. Vapors,
primarily water (steam) and glycol, are vented to a reflux column or distillation column. A heat exchanger
cools the vapors. Recovered glycol is returned to the primary esterifier. The water vapor is condensed using
29EC (85EF) cooling water in a shell-and-tube condenser and then is discharged to the waste water treatment
system. The monomer formed in the primary esterifier and the remaining reactants are pumped to the
secondary esterifier.

Kết quả (Việt) 3:

受管制的森林