CN-121988055-A - Triethylene glycol negative pressure regeneration system and method

CN121988055ACN 121988055 ACN121988055 ACN 121988055ACN-121988055-A

Abstract

The invention discloses a triethylene glycol negative pressure regeneration system and a method, which relate to the technical field of natural gas purification application and comprise a rectifying column, a heat exchanger, a flash tank, a buffer tank, a reboiler and a gas-liquid separator, wherein the rectifying column is arranged above the reboiler and is communicated with the reboiler, a preheating pipe is arranged above the interior of the rectifying column, the bottom of the reboiler is communicated with the buffer tank, a spiral pipe is arranged in the buffer tank, a lean solution outlet is arranged at the bottom of the buffer tank, a fire pipe is arranged in the reboiler, the outlet of the preheating pipe is connected with a material inlet of the heat exchanger through a pipeline J, the heat exchanger is connected with the flash tank, the flash tank is connected with the spiral pipe, the outlet of the flash tank is communicated with a feed inlet of the rectifying column, a gas outlet of the rectifying column is connected with a plurality of compressors, the compressors are connected with a medium inlet of the heat exchanger, the medium outlet of the compressors is connected with the gas-liquid separator, and the gas-liquid separator is communicated with a fuel gas inlet of the fire pipe, so that the purposes of low-temperature triethylene glycol regeneration, the scaling risk of the fire pipe is reduced, the running energy efficiency of the system is improved, and the running safety of the reboiler is achieved.

Inventors

SONG YINJUN
LI HAI
LI SHA
JIANG TINGTING
HE JIAN
ZOU DINGGUO

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241105

Claims (10)

1. The triethylene glycol negative pressure regeneration system is characterized by comprising a rectifying column, a heat exchanger, a flash tank, a buffer tank, a reboiler and a gas-liquid separator, wherein the rectifying column is arranged above the reboiler and is communicated with the reboiler; The inlet of the preheating pipe is communicated with a low Wen Fuye feed pipeline, the outlet of the preheating pipe is connected with the material inlet of the heat exchanger through a pipeline J, the material outlet of the heat exchanger is connected with the flash tank through a pipeline A, and the flash tank is connected with the spiral pipe through a pipeline G; The gas phase outlet of the rectifying column is connected with a plurality of compressors through a pipeline B, the compressors are connected with a medium inlet of the heat exchanger through a pipeline C, the medium outlet of the rectifying column is connected with a gas-liquid separator through a pipeline D, and the gas-liquid separator is communicated with a fuel gas inlet of the fire tube through a pipeline F.
2. The negative pressure triethylene glycol regeneration system according to claim 1, wherein the gas phase outlet of the rectification column is connected with a compressor I through a pipeline B, the compressor I is connected with a compressor II through a pipeline K, the compressor II is connected with a medium inlet of the heat exchanger through a pipeline C, the pipeline B is connected with a pipeline K through a pipeline E, the pipeline D is connected with the pipeline K through a pipeline L, a valve A and a valve B are arranged on the pipeline L, a valve C is arranged on the pipeline K, and a valve D is arranged on the pipeline E.
3. The triethylene glycol negative pressure regeneration system of claim 2, wherein the valve A, the valve B, the valve C and the valve D are all electromagnetic valves.
4. The triethylene glycol negative pressure regeneration system according to claim 2, wherein the reboiler is provided with a chimney, and the outlet of the fire tube is communicated with the chimney.
5. The method according to claim 4, wherein the gas-liquid separator is a gas-liquid cooling separator.
6. A method for regenerating triethylene glycol under negative pressure, characterized by comprising the following steps based on the triethylene glycol under negative pressure regeneration system according to claim 5: S1, enabling the collected triethylene glycol rich liquid to enter a preheating pipe in a rectifying column through a low Wen Fuye feeding pipeline, and performing heat exchange with regenerated tail gas generated in the rectifying column; S2, enabling the triethylene glycol rich liquid preheated in the step S1 to enter a heat exchanger through a pipeline J, and performing secondary heat exchange with the regenerated tail gas after being compressed and heated in the heat exchanger; S3, entering a flash tank through a pipeline A, reducing the pressure and the temperature, evaporating organic gas components in the triethylene glycol rich liquid, and discharging the organic gas components out of the system through a flash evaporation steam outlet; S4, the materials subjected to heat exchange in the step S3 enter the bottom of the rectifying column through a pipeline H and then enter a reboiler to perform heat exchange with a medium in a fire tube, the temperature is increased, water and part of organic matters in the materials are evaporated to form regenerated tail gas, the regenerated tail gas enters the upper part of the rectifying column, the rest triethylene glycol barren solution enters a buffer tank through a connecting pipe between the bottom of the reboiler and the buffer tank, exchanges heat with low Wen Fuye in a spiral tube, and finally is discharged out of the system through a buffer tank outlet and a barren solution outlet; s5, enabling tail gas discharged from the top of the rectifying column to enter a compressor for compression through a pipeline B, and enabling the tail gas to enter a heat exchanger for heat exchange through a pipeline C; S6, the materials subjected to heat exchange in the step S5 enter a gas-liquid cooling separator through a pipeline D to be separated, condensed water is generated and discharged through a drain outlet of the gas-liquid cooling separation, and the rest of regenerated tail gas is introduced into a fire tube through a pipeline F to be combusted together with fuel gas from a fuel gas inlet.
7. The method for negative pressure regeneration of triethylene glycol according to claim 6, wherein the temperature of the material at the outlet of the flash tank is denoted by T2, the temperature of the material at the outlet of the medium of the heat exchanger is denoted by T4, the upper pressure in the rectification column is denoted by P, When T4-T2 is smaller than a preset value T0, closing a valve A, a valve B and a valve D, opening a valve C, enabling the generated regenerated tail gas to enter a compressor I through a rectifying column outlet and a pipeline B, then enter a compressor II through the valve C, and adjusting the load of the compressor until P < P0, wherein P0 is a preset pressure value; When T4-T2 is larger than or equal to a preset value T0, closing a valve B and a valve C, opening a valve A and a valve D, enabling generated regenerated tail gas to enter a compressor I through a rectifying column outlet and a pipeline B, compressing and then introducing the regenerated tail gas into the pipeline C through the valve B, simultaneously entering a compressor II through a pipeline E and the valve D, and adjusting the load of the compressor to enable the internal pressure P of the rectifying column to approach P0 and the value of T4-T2 to approach T0; and when T4-T2 is far greater than T0, opening a valve B, and directly introducing the compressed regenerated tail gas into a gas-liquid cooling separator for cooling separation.
8. The method for negative pressure regeneration of triethylene glycol according to claim 6, wherein the pipeline A is provided with a temperature sensor I, and the temperature sensor I is used for detecting the temperature of the material at the outlet of the flash tank.
9. The method for negative pressure regeneration of triethylene glycol according to claim 6, wherein the pipeline D is provided with a temperature sensor II, and the temperature sensor II is used for detecting the temperature of materials at the medium outlet of the heat exchanger.
10. The method for negative pressure regeneration of triethylene glycol according to claim 6, wherein a pressure sensor is provided at the upper part of the rectification column.

Description

Triethylene glycol negative pressure regeneration system and method Technical Field The invention relates to the technical field of natural gas purification application, in particular to a triethylene glycol negative pressure regeneration system and a triethylene glycol negative pressure regeneration method. Background The strong absorbability of triethylene glycol on water can be utilized to efficiently remove water in target gas, and the method is widely applied to natural gas exploitation and purification processes. The triethylene glycol dehydration process is generally composed of main components such as an absorption tower, a filter, a preheater, a reboiler, a tail gas incinerator and the like. In the process, after the triethylene glycol is adopted for absorption dehydration, triethylene glycol rich liquid is required to be heated, and water in the triethylene glycol rich liquid is distilled out to realize the regeneration of the triethylene glycol. When the reboiler is used for heating and regenerating the rich triethylene glycol liquid, the system needs to be heated to about 180 ℃ or above, organic matters such as triethylene glycol are easy to deteriorate at high temperature, dense dirt is finally formed on the surface of a fire tube in the reboiler, the heating of the triethylene glycol is blocked, the heating efficiency of the reboiler is further reduced, and the problem of heat perforation of the fire tube is caused when the heating efficiency of the reboiler is serious. In addition, the method comprises the following steps. The tail gas discharged in the triethylene glycol regeneration process is generally close to 100 ℃, is rich in saturated vapor and a small amount of alkane alcohol organic substances, and carries a large amount of heat energy, wherein combustible components are burnt by adopting a burning furnace, so that the problem of energy waste exists. The high heating temperature results in a high exhaust gas temperature, and there is a problem in that the fuel heat energy is not fully utilized. Therefore, the triethylene glycol regeneration process or equipment in the prior art still needs to be optimized, and the triethylene glycol regeneration process or equipment with more reasonable design, more energy conservation, higher efficiency and safer design is needed to improve the technical problems in the prior art. Disclosure of Invention The invention aims to provide a triethylene glycol negative pressure regeneration method and a system, which can reduce the triethylene glycol regeneration heating temperature, reduce the exhaust gas temperature of a reboiler, utilize heat energy carried by regenerated tail gas, separate organic combustible components in the regenerated tail gas for combustion, and further realize the purposes of low-temperature triethylene glycol regeneration, reducing the scale formation risk of a fire tube, improving the operation energy efficiency of the system and enhancing the operation safety of the reboiler. The invention is realized by the following technical scheme: The triethylene glycol negative pressure regeneration system comprises a rectifying column, a heat exchanger, a flash tank, a buffer tank, a reboiler and a gas-liquid separator, wherein the rectifying column is arranged above the reboiler and is communicated with the reboiler, a preheating pipe is arranged above the interior of the rectifying column, the bottom of the reboiler is communicated with the buffer tank through a connecting pipe, a spiral pipe is arranged in the buffer tank, a lean liquid outlet is arranged at the bottom of the buffer tank, and a fire pipe is arranged in the reboiler; The inlet of the preheating pipe is communicated with a low Wen Fuye feed pipeline, the outlet of the preheating pipe is connected with the material inlet of the heat exchanger through a pipeline J, the material outlet of the heat exchanger is connected with the flash tank through a pipeline A, and the flash tank is connected with the spiral pipe through a pipeline G; The gas phase outlet of the rectifying column is connected with a plurality of compressors through a pipeline B, the compressors are connected with a medium inlet of the heat exchanger through a pipeline C, the medium outlet of the rectifying column is connected with a gas-liquid separator through a pipeline D, and the gas-liquid separator is communicated with a fuel gas inlet of the fire tube through a pipeline F. Further, the gas phase outlet of rectifying column passes through pipeline B and connects compressor I, and compressor I passes through pipeline K and connects compressor II, and compressor II passes through pipeline C and connects the medium import of heat exchanger, and pipeline B passes through pipeline E and connects pipeline K, and pipeline D passes through pipeline L and connects pipeline K, is equipped with valve A, valve B on the pipeline L, is equipped with valve C on the pipeline K, is equipped with valve D on the pipel