Natural gas dewatering system for using waste heat of molecular sieve regenerated gas

Abstract

The invention discloses a natural gas dewatering system for using waste heat of molecular sieve regenerated gas. The natural gas dewatering system comprises a first dewatering tower, a second dewatering tower, a dust filter, a mercury removal machine, a carbon dust filter, a regenerated gas heater, a regenerated gas cooler, a regenerated gas separator and a dewatering unit water carbon filter; a cold-hot regenerated gas heat exchange mechanism is additionally arranged and comprises a tube shell type cold-hot regenerated gas heat exchanger (1); hot regenerated gas and cold regenerated gas exchange heat in the cold-hot regenerated gas heat exchanger (1); the hot regenerated gas of a tube pass is cooled, and the cold regenerated gas of a shell pass is heated, so that the waste heat of the hotregenerated gas is recycled. A liquefaction plant with daily natural gas treatment capacity of one million standard m<3> / day is used as an example, the total heat regeneration annual operating time of two dewatering towers is 4,000 hours, and 1,800 MW waste heat can be recycled in one year and is equivalent to 268.28 tce (equivalent value) of standard coal. Through the natural gas dewatering system, the waste heat of the molecular sieve regenerated gas is recycled; the pollution to the environment is reduced; the natural gas dewatering system is energy-saving and environmentally friendly.

Description

technical field [0001] The invention belongs to the technical field of natural gas liquefaction, and in particular relates to a waste heat utilization scheme of molecular sieve regeneration gas of a dehydration unit. Background technique [0002] The natural gas liquefaction process is a series of processes in which the raw natural gas from the long-distance pipeline network is pressurized, purified, and then liquefied in a cold box. Before liquefaction, the raw natural gas must be purified and pretreated to remove impurities such as carbon dioxide, hydrogen sulfide, water, mercury, and heavy hydrocarbons contained in the raw natural gas. These substances will freeze at the low temperature used in the liquefaction process and block equipment or degrade the performance of the heat exchanger. [0003] For the dehydration unit, 4A molecular sieve is usually used for adsorption dehydration. Molecular sieves are regenerated by purging at elevated temperatures for reuse. Set up...

AI Technical Summary

Problems solved by technology

[0005] Regardless of whether the regenerative gas heater is heated by heat transfer oil or directly heated by the boiler, it needs to consume fuel gas

Regardless of whether the regenerative gas cooler is water-cooled or air-cooled, it consumes energy, water and electricity

The waste heat of the hot regeneration gas is not reused, resulting in a waste of energy in the heating and cooling process of the regeneration gas

Images