CN112107876A - Ethylene glycol rich solution regeneration dehydration system and method in deep sea natural gas exploitation process - Google Patents

Ethylene glycol rich solution regeneration dehydration system and method in deep sea natural gas exploitation process Download PDF

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Publication number
CN112107876A
CN112107876A CN202011030011.6A CN202011030011A CN112107876A CN 112107876 A CN112107876 A CN 112107876A CN 202011030011 A CN202011030011 A CN 202011030011A CN 112107876 A CN112107876 A CN 112107876A
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China
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tower
temperature
flow control
pressure
control valve
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Inventor
唐文献
王文涛
陈晨
何利
唐安能
程元康
黄潋之
苏世杰
张建
何佳伟
齐继阳
李华
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Jiangsu University of Science and Technology
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Jiangsu University of Science and Technology
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Priority to CN202011030011.6A priority Critical patent/CN112107876A/en
Publication of CN112107876A publication Critical patent/CN112107876A/en
Priority to PCT/CN2021/078291 priority patent/WO2022062316A1/en
Pending legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/02—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in boilers or stills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/42—Regulation; Control
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
    • C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
    • C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation

Abstract

The invention discloses a system and a method for regenerating and dehydrating ethylene glycol pregnant solution in the process of exploiting deep sea natural gas. The low-temperature glycol rich solution is heated by the salt-containing glycol barren solution with higher temperature through the heat exchanger, so that the cost required by heating the glycol rich solution is saved, and the efficiency of rectifying the glycol rich solution in the regeneration tower is improved; the liquid level, temperature, pressure, liquid concentration and the like are controlled by grading control at each key technical point. The normal work of the regeneration dehydration system is ensured through the control, the ethylene glycol regeneration dehydration rate is improved, and the operation efficiency of the system is improved; the vertical thermosyphon reboiler is adopted to heat the rich ethylene glycol solution, so that devices such as a transport pump are omitted, and the operation cost is effectively reduced.

Description

Ethylene glycol rich solution regeneration dehydration system and method in deep sea natural gas exploitation process
Technical Field
The invention relates to a system and a method for regenerating and dehydrating ethylene glycol rich solution in the process of exploiting deep sea natural gas.
Background
In the process of developing a deep sea natural gas field, along with the increase of water depth, hydrates are easily formed in a submarine pipeline under the condition of high-pressure conveying, so that equipment such as a pipeline valve and the like are blocked, and the normal operation of production is influenced. Therefore, hydrate inhibitors, most commonly ethylene glycol, need to be added to prevent hydrate formation during natural gas development.
Ethylene glycol is used as an important organic chemical raw material, and due to economic considerations, the ethylene glycol rich solution used as an inhibitor generally needs to be regenerated and recycled to remove redundant moisture and impurities in the ethylene glycol rich solution so as to reduce the use cost.
However, because the ethylene glycol and the water in the submarine pipeline are mutually dissolved to form the ethylene glycol rich solution, the ethylene glycol rich solution needs to be regenerated and recycled to remove redundant water and impurities, so that the use cost is reduced. During ethylene glycol regeneration, regeneration failures often occur. In view of the situation, the invention provides a glycol rich liquid regeneration dehydration system and a control system in the deep sea natural gas exploitation process.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: provides a system for regenerating and dehydrating ethylene glycol pregnant solution in the process of exploiting deep sea natural gas.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a glycol rich solution regeneration dehydration system in the process of exploiting deep sea natural gas comprises a glycol rich tank for storing a glycol rich solution from an upstream pretreatment system, wherein the glycol rich tank is connected with a rich solution delivery pump through a pipeline, a first stop valve is installed on the pipeline between the glycol rich tank and the rich solution delivery pump, and a first temperature gauge and a first pressure transmitter are installed on the pipeline between the glycol rich tank and the first stop valve; the output outlet of the rich liquid transport pump is connected with a three-way valve, and one way of the three-way valve is communicated to a rich liquid inlet of the heat exchanger through a pipeline; the other path of the three-way valve is connected with a first bypass stop valve through a pipeline and is connected to the feeding end of the first stop valve to form a bypass loop; a first check valve, a first electric valve and a first flow control valve are sequentially arranged on a pipeline between the rich liquid transport pump and the rich liquid inlet of the heat exchanger, and a first flow transmitter, a first flow controller and a first pressure gauge are arranged on the pipeline between the rich liquid inlet of the heat exchanger and the first flow control valve;
the heat exchanger rich liquid outlet is communicated with the middle part of the regeneration tower through a pipeline, a second check valve, a second flow control valve and a second electric valve are sequentially arranged on the pipeline between the heat exchanger rich liquid outlet and the regeneration tower, and a second thermometer, a first temperature transmitter, a second flow control instrument and a second pressure gauge are arranged on the pipeline between the second flow control valve and the second electric valve;
two liquid phase outlets are arranged on a tower kettle of the regeneration tower, a gas phase outlet is arranged at the top of the regeneration tower, the gas phase outlet at the top of the regeneration tower is communicated with an inlet of a condenser through a pipeline, one liquid phase outlet on the tower kettle of the regeneration tower is communicated with a barren liquor inlet of a heat exchanger through a barren liquor transport pump and a pipeline, the other liquid phase outlet on the tower kettle of the regeneration tower is communicated with an inlet of a vertical thermosyphon reboiler through a pipeline, and the outlet of the vertical thermosyphon reboiler is communicated with the middle part of the regeneration tower through a pipeline to form a circulating heating;
the upper part of the regeneration tower is provided with a second pressure transmitter, a first pressure controller, a fifth pressure gauge, a sixth temperature gauge and a third temperature transmitter which are used for monitoring the temperature and the pressure of the upper part of the regeneration tower in real time so as to adjust the opening degree of a third flow control valve; the middle part of the regeneration tower is provided with a third temperature meter and a fourth pressure transmitter which are used for monitoring the temperature and the pressure of the middle part of the regeneration tower, namely the feeding position of the regeneration tower in real time so as to adjust the opening of the second flow control valve; the bottom of the regeneration tower is provided with a first liquid level transmitter, a first liquid level controller, a first density display, a sixth pressure gauge, a third pressure controller, a seventh thermometer, a fourth temperature transmitter and a fifth pressure transmitter, and the first liquid level transmitter, the first liquid level controller, the first density display, the sixth pressure gauge, the third pressure controller, the seventh thermometer, the fourth temperature transmitter and the fifth pressure transmitter are used for monitoring the temperature, the pressure, the liquid level and the ethylene glycol concentration at the bottom of the regeneration tower in real time so as to adjust the opening degrees of the second flow control valve;
a pipeline between a tower top gas phase outlet of the regeneration tower and a condenser inlet is provided with a second pressure controller, a fourth thermometer, a third pressure gauge and a third one-way valve; the outlet of the condenser is communicated with the condensate tank through a pipeline, and a fourth check valve and a second temperature transmitter are arranged on the pipeline between the outlet of the condenser and the condensate tank; the condensate tank is provided with two liquid phase outlets positioned at the bottom of the tank and a gas phase outlet positioned at the top of the tank, the gas phase outlet at the top of the condensate tank is connected with the vacuum pump through a pipeline, and a second stop valve is arranged between the outlet at the top of the condensate tank and the vacuum pump through a pipeline;
one of two liquid phase outlets of the condensate tank is connected with the upper part of the regeneration tower through a pipeline to provide reflux required by rectification, a fifth one-way valve, a third flow control valve and a third electric valve are arranged on a pipeline between the condensate tank and the regeneration tower, and a third pressure transmitter, a fifth thermometer, a third flow transmitter, a third flow control instrument and a fourth pressure gauge are arranged on a pipeline between the condensate tank and the regeneration tower and used for monitoring the flow, the temperature and the pressure of the reflux at the top of the tower in real time to adjust the opening sizes of the second flow control valve, the third flow control valve and the fourth flow control valve; a liquid phase outlet of the other condensate tank is communicated with a condensate pump inlet through a pipeline, a fifth one-way valve is arranged on a pipeline between the condensate tank and the condensate pump inlet, a condensate pump outlet is communicated with a seventh one-way valve through a pipeline, and a second liquid level transmitter, a second liquid level controller, a thirteenth temperature gauge and a tenth pressure gauge are further arranged on a condensate tank body so as to adjust the condensate pump according to the measured liquid level of the condensate tank;
the tower kettle of the regeneration tower is communicated with an inlet of the vertical thermosiphon reboiler through a pipeline, an eighth one-way valve, a fourth flow control valve and a fourth electric valve are arranged on the pipeline between the tower kettle of the regeneration tower and the inlet of the vertical thermosiphon reboiler, and a seventh pressure gauge, an eighth thermometer, a fifth temperature transmitter, a fourth flow transmitter and a fourth flow control instrument are further arranged on the pipeline between the tower kettle of the regeneration tower and the inlet of the vertical thermosiphon reboiler and used for monitoring the temperature, the pressure and the flow in the pipeline between the tower kettle of the regeneration tower and the inlet of the vertical thermosiphon reboiler; an outlet of the vertical thermosyphon reboiler is communicated with the bottom of the regeneration tower through a pipeline, a fifth electric valve and a ninth one-way valve are arranged between the outlet of the vertical thermosyphon reboiler and the bottom of the regeneration tower, and an eighth pressure gauge, a sixth temperature transmitter, a first temperature controller and a ninth thermometer are further arranged between the outlet of the vertical thermosyphon reboiler and the bottom of the regeneration tower for monitoring the temperature and the pressure in the pipeline in real time so as to adjust the opening degrees of the second flow control valve, the third flow control valve and the fourth flow control valve;
the regeneration tower kettle is communicated with an inlet of a barren liquor transport pump through a pipeline, a seventh electric valve and a third stop valve are sequentially installed on the pipeline between the regeneration tower kettle and the inlet of the barren liquor transport pump, an outlet of the barren liquor transport pump is connected with a three-way valve, one path of the outlet of the three-way valve is connected with a barren liquor inlet of a heat exchanger through a pipeline, and the other path of the outlet of the three-way valve is connected with a liquid inlet of the third stop valve through a pipeline provided with a second bypass stop; a tenth check valve and a sixth electric valve are sequentially arranged on a pipeline between the lean solution transport pump and the lean solution inlet of the heat exchanger, and a sixth pressure transmitter, a seventh temperature transmitter and an eleventh thermometer are further arranged on the pipeline between the lean solution transport pump and the lean solution inlet of the heat exchanger; and a lean solution outlet of the heat exchanger is communicated with a pipeline provided with an eleventh check valve.
As a preferable scheme, a twelfth thermometer and a ninth pressure gauge are arranged on an outlet pipeline of the eleventh check valve.
Preferably, a safety relief valve for relief when the tower top pressure is too high is arranged at the top of the regeneration tower.
The technical problem to be solved by the invention is as follows: the ethylene glycol regeneration method of the ethylene glycol rich solution regeneration dehydration system in the deep sea natural gas exploitation process is provided.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the glycol regeneration method of the glycol rich solution regeneration dehydration system in the process of exploiting the deep sea natural gas comprises the following steps:
step 1: in the initial state, valves in each system are in a closed state; the method comprises the steps that firstly, a first stop valve and a first bypass stop valve are opened, a rich liquid transport pump is started, when a bypass loop between an ethylene glycol-rich tank and the rich liquid transport pump is filled with ethylene glycol rich liquid, a first pressure transmitter detects that the pressure in the pipe is stable, then a first electric valve is opened through remote control, a first flow control valve is opened, the first bypass stop valve is closed, and the ethylene glycol rich liquid with the temperature of about 70 ℃ is transported into a heat exchanger;
step 2: carrying out heat exchange on the qualified ethylene glycol barren solution with the temperature of 139 +/-5 ℃ output from the tower kettle of the regeneration tower and the ethylene glycol rich solution with the temperature of 70 ℃ in the step 1 through a heat exchanger, detecting the temperature of the ethylene glycol rich solution in the pipe through a second thermometer and a first temperature transmitter after the heat exchange, controlling a first flow control valve on a feeding pipe through a computer, adjusting the flow of the rich solution outlet of the heat exchanger, and maintaining the temperature of the ethylene glycol rich solution at the rich solution outlet of the heat exchanger to be stable;
and step 3: ethylene glycol rich liquid with the temperature of 85 +/-5 ℃ output from a rich liquid outlet of the heat exchanger enters the middle of the regeneration tower, the temperature and the pressure of an inlet in the middle of the regeneration tower are detected through a third temperature meter and a fourth pressure transmitter in the middle of the regeneration tower, a second flow control valve is controlled through a computer to adjust the feeding flow of the regeneration tower, the temperature and the pressure in the regeneration tower are maintained to be stable, and the pressure in the regeneration tower is kept at 30 +/-10 KPa;
and 4, step 4: the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ flows downwards along a second section packing layer in the regeneration tower, the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ is continuously contacted with upward flowing hot steam generated by a vertical thermosiphon reboiler and continuously conducts heat, so that the temperature of the ethylene glycol rich solution is gradually increased, after the temperature reaches 139 +/-5 ℃, heavy components and light components in the ethylene glycol rich solution are separated, the heavy components flow downwards into a tower kettle, the light components rise to the top of the tower and are discharged into a condenser through a gas phase outlet at the top of the regeneration tower;
and 5: the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ flows downwards to a tower kettle along a second section packing layer in the regeneration tower, the ethylene glycol rich solution is input into a vertical thermosiphon reboiler from the tower kettle of the regeneration tower for circulating heating, circulating power is derived from the liquid level of the tower kettle of the regeneration tower and the density difference of two-phase fluid in the vertical thermosiphon reboiler, the vertical thermosiphon reboiler is heated by a heat medium, the heat medium flows through a shell pass, the ethylene glycol liquid flows through a tube pass, and the ethylene glycol liquid with the temperature of 139 +/-5 ℃ is input into the middle bottom of the regeneration tower from an outlet of the vertical thermosiphon reboiler;
step 6, cooling a gas-phase product generated at the top of the regeneration tower to 30-40 ℃ through a condenser, and feeding condensed water into a condensed water tank for storage;
step 7, pumping out a small amount of non-condensable gas in the condensate tank through a gas phase outlet at the top of the condensate tank by a vacuum pump and discharging;
step 8, condensing the gas phase at the top of the regeneration tower, converting the gas phase into a liquid phase, and refluxing 3-6% of condensed water from a condensate tank to the top of the regeneration tower; the flow of the reflux liquid of the third flow control valve is controlled by the temperature, the pressure and the flow of the reflux liquid on a pipeline connecting the condensate tank and the top of the regeneration tower so as to maintain the temperature and the pressure at the top of the regeneration tower to be stable;
step 9, when the liquid level of the condensate tank exceeds the warning height of the second liquid level controller, opening a condensate pump to discharge condensate in the condensate tank;
step 10, detecting the ethylene glycol barren solution at the tower bottom of the regeneration tower to be qualified through a first density display, and opening a barren solution conveying pump to convey the ethylene glycol barren solution after the concentration of the ethylene glycol reaches above;
step 11, conveying the qualified glycol solution to a lean solution inlet of a heat exchanger to exchange heat with a glycol rich solution;
and 12, after the ethylene glycol barren solution exchanges heat with the ethylene glycol rich solution in the heat exchanger, discharging the ethylene glycol barren solution at the temperature of 95 +/-5 ℃ from a barren solution outlet of the heat exchanger so as to send the ethylene glycol barren solution to a desalination system connected with the heat exchanger.
As a preferable scheme, the temperature of the rich liquid outlet of the heat exchanger is controlled to keep the temperature of the rich liquid outlet of the heat exchanger at a set value of the temperature of the rich liquid outlet of 85 +/-5 ℃, a first temperature transmitter on a rich liquid outlet pipeline of the heat exchanger is provided with an over-temperature alarm and an under-temperature alarm, and when the temperature is not within a normal range and the alarms are triggered, the following steps are carried out:
when the temperature of the rich liquid outlet of the heat exchanger is lower than the set temperature and is too low, and the triggering temperature is too low to alarm, if the heat exchanger is not started, the heat exchanger is started;
if the heat exchanger is working at the moment, but the temperature of the barren solution inlet of the heat exchanger is too low and does not reach the set temperature value, so that the heat exchange performance of the heat exchanger cannot meet the requirement, the rich solution outlet of the heat exchanger is opened after the temperature of the tower kettle of the regeneration tower reaches the set temperature value;
if the liquid level of the tower kettle is too high and the temperature of the tower kettle of the regeneration tower cannot reach the set temperature value, reducing the opening degrees of the first flow control valve and the second flow control valve, continuously rectifying along with the regeneration tower, continuously reducing the liquid level of the tower kettle, inputting the glycol barren solution in the tower kettle to a barren solution inlet of a heat exchanger after the outlet temperature of the vertical thermosiphon reboiler meets the requirement, and simultaneously opening the opening degrees of the first flow control valve and the second flow control valve to be normal;
if the temperature of the tower kettle meets the requirement of a set temperature value, controlling the opening degrees of the first flow control valve and the second flow control valve, and controlling the liquid-phase feeding temperature by controlling the flow;
when the temperature of a rich liquid outlet of the heat exchanger is too high, which causes the triggering of an over-high temperature alarm, if the temperature of a lean liquid in a tower kettle of the regeneration tower is too high, the opening degrees of the first flow control valve and the second flow control valve are adjusted to be the maximum, and meanwhile, the opening degree of the third flow control valve is opened to be within an allowable range.
As a preferred scheme, tower cauldron liquid level changer sets up liquid level limit too high warning, liquid level and crosses low warning and liquid level limit and crosses low warning, when the liquid level is not in normal range, when leading to having triggered above warning, handles according to following mode:
if the liquid level at the tower kettle in the regeneration tower is too high and exceeds a preset limit height value, so that the liquid level limit at the tower kettle is triggered to alarm too high, a second electric valve of the feeding pipeline and a third electric valve of the return pipeline are cut off, and whether flooding occurs or not is judged; if the flooding occurs, processing according to a flooding processing method;
if no flooding occurs and the barren solution in the tower kettle meets the production requirement, increasing the discharge amount of the tower kettle, and opening a barren solution transport pump P-2 to the maximum so as to adjust the liquid level of the tower kettle;
if the quality of the barren solution in the tower kettle is not qualified, stopping discharging the tower kettle solution, opening the opening of a fourth flow opening valve at the inlet of a reboiler to the maximum amount within an allowable range, improving the rectification efficiency of the regeneration tower, separating out light components until the barren solution in the tower kettle is qualified and discharged, and enabling the liquid level in the tower kettle to be at a normal level; opening a second electric valve and a third electric valve for normal feeding after the liquid level of the tower kettle is normal, and opening the opening degree of a fourth flow opening valve to a set normal amount;
if the liquid level at the tower kettle in the regeneration tower causes triggering of an over-high liquid level alarm, judging whether flooding occurs or not, if flooding occurs, processing according to a flooding processing method, if flooding does not occur, observing a density display and a seventh thermometer to know the concentration and temperature of the barren solution in the tower kettle, if production requirements are met, increasing the discharge capacity of the tower kettle, and opening the working efficiency of a barren solution transport pump to the maximum, so that the liquid level of the tower kettle is adjusted;
if the quality of the barren solution in the tower kettle is not qualified, stopping discharging the tower kettle solution; opening the first flow control valve, the second flow control valve and the third flow control valve to the minimum, reducing the feeding flow, opening the fourth flow opening valve of the reboiler to the maximum within the allowable range, increasing the rectification efficiency of the regeneration tower, separating out light components, ensuring that the barren solution in the tower kettle is qualified and discharged, and ensuring that the liquid level in the tower kettle is at the normal level; opening degrees of a first flow control valve, a second flow control valve, a third flow control valve and a fourth flow opening valve to set normal quantities after the liquid level of the tower kettle is normal;
if the liquid level at the tower bottom of the regeneration tower is too low, triggering an alarm of too low liquid level, judging whether the liquid level is caused by the occurrence of flooding, and if so, processing according to a flooding processing method; if the flooding does not occur, stopping discharging the tower kettle liquid, and judging whether the ethylene glycol rich liquid feeding liquid in the regeneration tower is insufficient due to the fact that whether a feeding loop is cut off or not;
if the liquid phase feeding loop is cut off at this time, a second electric valve on the feeding loop is opened firstly; if the liquid phase feeding loop is not cut off at the moment, and the opening degree of a second flow control valve in the feeding loop reaches the maximum, the reflux quantity at the top of the tower is increased at the same time, the opening degree of a third flow control valve reaches the maximum, and when the liquid level of the tower kettle is at a normal level, the opening degrees of the second flow control valve and the third flow control valve are opened to be normal;
if the liquid level at the tower kettle in the regeneration tower is lower than a preset limit low liquid level value, triggering a liquid level limit low alarm, immediately stopping the discharge of the tower kettle liquid, and simultaneously judging whether the liquid level is due to the occurrence of flooding, if so, processing the liquid level according to a flooding processing method; if the liquid flooding does not occur, closing the fourth electric valve, and closing the vertical thermosiphon reboiler; judging whether the feeding is insufficient due to the fact that the feeding loop is cut off, and if so, opening a second electric valve;
if the feed loop is not cut off, opening the first flow control valve, the second flow control valve and the third flow control valve to the maximum; the liquid level of the tower kettle is gradually increased, and when the liquid level is higher than the set lowest liquid level, a fourth electric valve is opened to restart the vertical thermosiphon reboiler; opening the opening degrees of the first flow control valve, the second flow control valve and the third flow control valve to normal values when the liquid level of the tower kettle reaches a set normal value;
as a preferable scheme, the pressure transmitter of the regeneration tower kettle is provided with a pressure limit over-low alarm, a pressure over-high alarm and a pressure limit over-high alarm, and when the pressure in the regeneration tower kettle is not within a normal range and causes a corresponding alarm to be triggered, the pressure is processed in the following manner:
when the pressure of the tower kettle is continuously overhigh to trigger an overhigh pressure limit value and give an alarm, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, temporarily closing the fourth electric valve and stopping the discharge of the tower kettle by cutting off the seventh electric valve, opening the second flow control valve and the third flow control valve to the maximum, opening the fourth electric valve and opening the second flow control valve and the third flow control valve to the normal after the pressure of the tower kettle is recovered to a set normal level, and opening the seventh electric valve to discharge qualified ethylene glycol from the tower kettle;
when the pressure of the tower kettle is too high and the pressure too high alarm is triggered, firstly, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the opening degree of the fourth flow control valve to the minimum allowable value, stopping discharging from the tower kettle by cutting off the seventh electric valve, opening the openings of the second flow control valve and the third flow control valve to the maximum, opening the seventh electric valve to discharge qualified glycol from the tower kettle after the pressure is recovered to a set normal value, opening the fourth electric valve, and opening the opening degrees of the second flow control valve and the third flow control valve to the normal value;
when the pressure in the tower kettle is too low and the alarm of too low pressure is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the second flow control valve and the third flow control valve to the minimum, opening the fourth flow control valve to the maximum, and opening the fourth flow control valve, the second flow control valve and the third flow control valve to the normal value after the pressure is recovered to the set normal value;
when the pressure in the tower kettle is low enough to trigger the alarm of too low pressure limit, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, opening the opening degree of the fourth flow control valve to the maximum allowable value, closing the first electric valve, the second electric valve and the third electric valve so as to cut off the feeding, opening the first electric valve, the second electric valve and the third electric valve after the pressure is recovered to a normal level, and opening the opening degree of the fourth flow control valve to a normal value;
as a preferable scheme, the second pressure transmitter at the top of the regeneration tower is provided with a pressure limit too low alarm, a pressure too high alarm and a pressure limit too high alarm, and when the pressure in the top of the regeneration tower is not within a normal range, which causes triggering of the corresponding alarm, the following processing is performed:
when the pressure at the top of the tower is continuously too low and the alarm of too low pressure limit is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, temporarily closing the gas phase outlet at the top of the tower and the third electric valve, and opening the gas phase outlet at the top of the tower and the third electric valve after the pressure is recovered to a set normal level;
when the pressure at the top of the tower is too low, and the pressure too low alarm is triggered, firstly, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, opening the third flow control valve to the minimum allowable value, and after the pressure is recovered to a certain level, opening the third flow control valve to a set normal value;
when the pressure at the tower top is too high, so that the over-pressure alarm is triggered, opening the third flow control valve to the maximum allowable value, and after the pressure is restored to the normal level, opening the third flow control valve to the normal value;
when the pressure in the tower top is continuously overhigh and the alarm of overhigh pressure limit is triggered, the safety pressure relief valve at the tower top is automatically opened and is automatically closed after the pressure is restored to a normal level;
as a preferred scheme, in the operation process of the regeneration dehydration system, when liquid phase feeding, tower top reflux and tower kettle discharging are in normal conditions, two or more conditions of too low liquid level of the tower kettle, higher outlet temperature of the vertical thermosiphon reboiler than a set value, higher pressure difference between the tower top and the tower kettle than a set value, increased temperature in the middle of the tower and lower temperature of the tower top occur, the occurrence of flooding is judged, and the flooding treatment is as follows: adjusting a second flow control valve to reduce or suspend the rich liquid feeding of the regeneration tower, adjusting the opening degree of a third flow control valve, ensuring the reflux of the tower top to return the ethylene glycol liquid at the tower top to the tower again, and keeping the liquid level height of the tower kettle not to be reduced any more; and (4) keeping the steam amount, and eliminating accumulated liquid in the packing in the tower kettle in an evaporation mode until the heat penetrates through the packing to enable the pressure difference to fall back to a set normal level and reestablish the gas-liquid balance.
As a preferred scheme, the control of the reflux temperature and flow rate of the overhead condensate and the liquid level in the condensate tank is as follows:
when the fifth thermometer detects that the temperature of the reflux is too high and triggers an over-temperature alarm, the flow of the cooling liquid in the condenser is increased through a third flow control valve until the temperature of the reflux liquid is at a normal level;
when the fifth thermometer detects that the temperature of the reflux is too low and triggers a too low temperature alarm, the flow of the cooling liquid in the condenser is reduced through a third flow control valve until the temperature of the reflux is at a normal level;
when the second liquid level transmitter detects that the liquid level of the condensate tank is too high, the condensate pump directly discharges the liquid in the condensate tank.
The invention has the beneficial effects that: the low-temperature glycol rich solution is heated by the salt-containing glycol barren solution with higher temperature through the heat exchanger, so that the cost required by heating the glycol rich solution is saved, and the efficiency of rectifying the glycol rich solution in the regeneration tower is improved; the liquid level, temperature, pressure, liquid concentration and the like are controlled by grading control at each key technical point. The normal work of the regeneration dehydration system is ensured through the control, the ethylene glycol regeneration dehydration rate is improved, and the operation efficiency of the system is improved; the vertical thermosyphon reboiler is adopted to heat the rich ethylene glycol solution, so that devices such as a transport pump are omitted, and the operation cost is effectively reduced.
The feed liquid transportation in the system adopts a bypass loop mode, so that the stability of a pipeline in the solution transportation process can be ensured, and the safety of the whole system is improved; the tower top of the regeneration tower refluxes, and the reflux quantity is accurately controlled through the flow control valve, so that the overall regeneration dehydration efficiency is effectively improved, and the operation cost is reduced.
If the temperature of the rich liquid outlet of the heat exchanger does not reach the set temperature, the overall operation of the ethylene glycol regeneration system is low in efficiency, energy is consumed, extra cost is increased, and more energy is needed to realize dehydration of the rich ethylene glycol liquid. The method controls the temperature of the rich liquid outlet of the heat exchanger to keep the temperature of the rich liquid outlet of the heat exchanger at a set value of the temperature of the rich liquid outlet of 85 +/-5 ℃, so that the normal working environment of relevant instruments and equipment can be ensured, and the efficiency of dehydrating the ethylene glycol rich liquid is improved.
If the liquid level in the tower kettle of the regeneration tower is too high, the liquid enters a reboiler in a countercurrent way through a gas phase feed inlet pipe, so that the parameters of the produced glycol barren solution are unqualified; if the liquid level of the tower kettle is continuously too high and slowly overflows to the gas phase feeding port pipe, the liquid enters the reboiler in a counter-flow manner through the gas phase feeding port pipe, so that the parameters of the produced lean ethylene glycol liquid are unqualified. Secondly, the liquid level in the tower kettle cannot be too low, the liquid level is too low, the gasification rate of a reboiler is increased, the gas velocity is too high, flooding is caused, the operation in the regeneration tower is influenced, and the parameters of the produced glycol barren solution are unqualified. The method solves the problems by well realizing the control of the liquid level in the tower kettle. And the liquid level position of the tower kettle is controlled to prevent the heating device from being burnt out. The liquid level of the tower kettle is controlled, namely the volume of the liquid in the tower kettle is controlled, otherwise, the flow of rising steam is influenced, and thus the material balance, the heat balance and the phase balance are influenced.
In the method, after the liquid level in the regeneration tower is kept at a normal level, the pressure in the regeneration tower is controlled to keep the liquid level normal, so that the normal working environment of related instruments and equipment is ensured, and the rectification efficiency of the regeneration tower is improved.
In the method, after the liquid level and the pressure in the regeneration tower are kept at normal levels, the temperature in the regeneration tower is controlled to be kept normal, so that the normal working environment of related instruments and equipment is further ensured, and the rectification efficiency of the regeneration tower is improved.
If the gas phase speed in the regeneration tower is too high, the liquid in the packed tower cannot smoothly flow down through the packing layer by self gravity, accumulated liquid is formed in the packing layer to cause flooding, the flooding of the regeneration tower causes the pressure difference between the tower top and the tower kettle to rise, the separation efficiency is reduced, the parameters of the produced lean glycol liquid are unqualified, the glycol content in the tower top is too high, and the solution can possibly immerse a demister arranged at the top of the regeneration tower to corrode the demister to cause the demister to fail to work.
Drawings
Fig. 1 is a schematic structural view of the present invention.
FIG. 2 is a flow chart of feed temperature control.
FIG. 3 is a flow chart of the control of the liquid level in the column bottom.
FIG. 4 is a flow chart for controlling the column bottom pressure.
Fig. 5 is a column top pressure control flow chart.
In the figure: the system comprises an ethylene glycol rich tank G-1, a rich liquid transport pump P-1, a heat exchanger E-1, a regeneration tower T-1, a condenser E-2, a condensate tank G-2, a vertical thermosyphon reboiler E-3, a lean liquid transport pump P-2, a condensate pump P-3 and a vacuum pump P-4.
A first stop valve V-1, a first bypass stop valve V-2, a first check valve V-3, a first electric valve V-4, a first flow control valve V-5, a second check valve V-6, a second flow control valve V-7, a second electric valve V-8, a third check valve V-9, a fourth check valve V-10, a fifth check valve V-11, a third flow control valve V-12, a third electric valve V-13, a second stop valve V-14, a sixth check valve V-15, a seventh check valve V-16, an eighth check valve V-17, a fourth flow control valve V-18, a fourth electric valve V-19, a fifth electric valve V-20, a ninth check valve V-21, a third stop valve V-22, a second bypass stop valve V-23, a tenth check valve V-24, a sixth electric valve V-25, an eleventh check valve V-26, a regeneration tower top safety pressure relief valve V-27 and a seventh electric valve V-28.
A first temperature meter 1#, a first pressure transmitter 2#, a first flow transmitter 3#, a first flow controller 4#, a first pressure gauge 5#, a second temperature meter 6#, a first temperature transmitter 7#, a second flow transmitter 8#, a second flow controller 9#, a second pressure gauge 10#, a third temperature meter 11#, a second pressure transmitter 12#, a first pressure controller 13#, a fourth temperature meter 14#, a third pressure gauge 15#, a second temperature transmitter 16#, a third pressure transmitter 17#, a fifth temperature meter 18#, a third flow transmitter 19#, a third flow controller 20#, a fourth pressure gauge 21#, a second pressure controller 22#, a fifth pressure gauge 23#, a sixth temperature meter 24#, a third temperature transmitter 25#, a fourth pressure transmitter 26#, a first liquid level controller 27#, a first liquid level controller 28, a first density display 29#, a sixth pressure gauge 30#, a third pressure controller 31#, a seventh temperature gauge 32#, a fourth temperature transmitter 33#, a fifth pressure transmitter 34#, a seventh pressure gauge 35#, an eighth temperature gauge 36#, a fifth temperature transmitter 37#, a fourth flow transmitter 38#, a fourth flow controller 39#, an eighth pressure gauge 40#, a sixth temperature transmitter 41#, a first temperature controller 42#, a ninth temperature gauge 43#, a tenth temperature gauge 44#, a sixth pressure transmitter 45#, a seventh temperature transmitter 46#, an eleventh temperature gauge 47#, a twelfth temperature gauge 48#, a ninth pressure gauge 49#, a second level transmitter 50#, a second liquid level controller 51#, a thirteenth temperature gauge 52#, a tenth pressure gauge 53 #.
Detailed Description
Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As shown in figure 1, the ethylene glycol rich solution regeneration and dehydration system in the process of exploiting the deep sea natural gas comprises an ethylene glycol rich tank G-1 for storing an ethylene glycol rich solution from an upstream pretreatment system, wherein the ethylene glycol rich tank G-1 is connected with a rich solution delivery pump P-1 through a pipeline, a first stop valve V-1 is installed on the pipeline between the ethylene glycol rich tank G-1 and the rich solution delivery pump P-1, and a first temperature meter 1# and a first pressure transmitter 2# are installed on the pipeline between the ethylene glycol rich tank and the first stop valve V-1; an output outlet of the rich liquid transport pump P-1 is connected with a three-way valve, and one path of the three-way valve is communicated to a rich liquid inlet of the heat exchanger E-1 through a pipeline; the other path of the three-way valve is connected with a first bypass stop valve V-2 through a pipeline and is connected to the feeding end of a first stop valve V-1 to form a bypass loop; a first check valve V-3, a first electric valve V-4 and a first flow control valve V-5 are sequentially arranged on a pipeline between a rich liquid transportation pump P-1 and a rich liquid inlet of a heat exchanger E-1, and a first flow transmitter 3#, a first flow controller 4# and a first pressure gauge 5# are arranged on the pipeline between the rich liquid inlet of the heat exchanger E-1 and the first flow control valve V-5;
a rich liquid outlet of the heat exchanger E-1 is communicated with the middle part of the regeneration tower T-1 through a pipeline, a second one-way valve V-6, a second flow control valve V-7 and a second electric valve V-8 are sequentially installed on the pipeline between the rich liquid outlet of the heat exchanger E-1 and the regeneration tower T-1, and a second thermometer 6#, a first temperature transmitter 7#, a second flow transmitter 8#, a second flow controller 9# and a second pressure gauge 10# are installed on the pipeline between the second flow control valve V-7 and the second electric valve V-8;
two liquid phase outlets are arranged on a tower kettle of the regeneration tower, a gas phase outlet is arranged at the top of the regeneration tower, the gas phase outlet at the top of the regeneration tower T-1 is communicated with an inlet of a condenser E-2 through a pipeline, one liquid phase outlet on the tower kettle of the regeneration tower is communicated with a barren liquor inlet of a heat exchanger E-1 through a barren liquor transfer pump P-2 and a pipeline, the other liquid phase outlet on the tower kettle of the regeneration tower is communicated with an inlet of a vertical thermosyphon reboiler E-3 through a pipeline, and an outlet of the vertical thermosyphon reboiler E-3 is communicated with the middle part of the regeneration tower through a pipeline to form a circulating heating loop;
the upper part of the regeneration tower T-1 is provided with a second pressure transmitter 12#, a first pressure controller 13#, a fifth pressure gauge 23#, a sixth thermometer 24# and a third temperature transmitter 25# which are used for monitoring the temperature and the pressure of the middle upper part of the regeneration tower T-1 in real time so as to adjust the opening degree of a third flow control valve V-12; the middle part of the regeneration tower is provided with a third thermometer 11# and a fourth pressure transmitter 26# which are used for monitoring the temperature and the pressure of the middle part of the regeneration tower T-1, namely the feeding position of the regeneration tower in real time so as to adjust the opening degree of a second flow control valve V-7; the bottom of the regeneration tower T-1 is provided with a first liquid level transmitter 27#, a first liquid level controller 28#, a first density display 29#, a sixth pressure gauge 30#, a third pressure controller 31#, a seventh temperature gauge 32#, a fourth temperature transmitter 33# and a fifth pressure transmitter 34# for monitoring the temperature, the pressure, the liquid level and the ethylene glycol concentration at the bottom of the regeneration tower T-1 in real time so as to adjust the opening degrees of the second flow control valve V-7, the third flow control valve V-12 and the fourth flow control valve V-18;
a second pressure controller 22#, a fourth thermometer 14#, a third pressure gauge 15# and a third check valve V-9 are arranged on a pipeline between the tower top gas phase outlet of the regeneration tower T-1 and the inlet of the condenser E-2; an outlet of the condenser E-2 is communicated with a condensate tank G-2 through a pipeline, and a fourth check valve V-10 and a second temperature transmitter 16# are arranged on the pipeline between the condenser E-2 and the condensate tank G-2; the condensate tank G-2 is provided with two liquid phase outlets positioned at the bottom of the tank and a gas phase outlet positioned at the top of the tank, the gas phase outlet at the top of the condensate tank G-2 is connected with the vacuum pump P-4 through a pipeline, and a second stop valve V-14 is arranged between the outlet at the top of the condensate tank G-2 and the vacuum pump P-4 through a pipeline;
one of two liquid phase outlets of the condensate tank G-2 is connected with the upper part of the regeneration tower T-1 through a pipeline to provide reflux liquid required by rectification, a fifth one-way valve V-11, a third flow control valve V-12 and a third electric valve V-13 are arranged on a pipeline between the condensate tank G-2 and the regeneration tower T-1, and a third pressure transmitter 17#, a fifth thermometer 18#, a third flow transmitter 19#, a third flow controller 20# and a fourth pressure gauge 21# are arranged on a pipeline between the condensate tank G-2 and the regeneration tower T-1 and used for monitoring the flow, the temperature and the pressure of reflux liquid at the tower top in real time so as to adjust the opening sizes of the second flow control valve V-7, the third flow control valve V-12 and the fourth flow control valve V-18; a liquid phase outlet of the other condensate tank G-2 is communicated with an inlet of the condensate pump P-3 through a pipeline, a fifth one-way valve V-15 is arranged on a pipeline between the two, an outlet of the condensate pump P-3 is communicated with a seventh one-way valve V-16 through a pipeline, and a second liquid level transmitter 50#, a second liquid level controller 51#, a thirteenth temperature meter 52# and a tenth pressure meter 53# are further arranged on a tank body of the condensate tank G-2 so as to adjust the condensate pump P-3 according to the measured liquid level of the condensate tank;
the regeneration tower T-1 is communicated with the inlet of the vertical thermosiphon reboiler E-3 through a pipeline, an eighth check valve V-17, a fourth flow control valve V-18 and a fourth electric valve V-19 are arranged on the pipeline between the regeneration tower T-1 and the vertical thermosiphon reboiler E-3, and a seventh pressure gauge 35#, an eighth thermometer 36#, a fifth temperature transmitter 37#, a fourth flow transmitter 38# and a fourth flow control instrument 39# are further arranged on the pipeline between the regeneration tower T-1 and the inlet of the vertical thermosiphon reboiler E-3 for monitoring the temperature, the pressure and the flow in the pipeline between the regeneration tower T-1 and the inlet of the vertical thermosiphon reboiler E-3 in real time so as to adjust the opening degree of the fourth flow control; an outlet of the vertical thermosyphon reboiler E-3 is communicated with the bottom of the regeneration tower T-1 through a pipeline, a fifth electric valve V-20 and a ninth one-way valve V-21 are arranged between the outlet of the vertical thermosyphon reboiler E-3 and the bottom of the regeneration tower T-1, and an eighth pressure gauge 40#, a sixth temperature transmitter 41#, a first temperature controller 42# and a ninth temperature gauge 43# are further arranged between the outlet of the vertical thermosyphon reboiler E-3 and the bottom of the regeneration tower T-1 for monitoring the temperature and the pressure in the pipeline in real time so as to adjust the opening degree of the second flow control valve V-7, the third flow control valve V-12 and the fourth flow control valve V-18;
the regeneration tower T-1 is communicated with the inlet of a barren liquor transport pump P-2 through a pipeline, a seventh electric valve V-28 and a third stop valve V-22 are sequentially installed on the pipeline between the regeneration tower T-1 and the barren liquor transport pump P-2, the outlet of the barren liquor transport pump P-2 is connected with a three-way valve, one path of the outlet of the three-way valve is connected with the barren liquor inlet of a heat exchanger E-1 through a pipeline, and the other path of the outlet of the three-way valve is connected with the liquid inlet of the third stop valve V-22 through a pipeline provided with a second bypass stop valve V-; a tenth check valve V-24 and a sixth electric valve V-25 are sequentially arranged on a pipeline between the lean solution transportation pump P-2 and the lean solution inlet of the heat exchanger E-1, and a sixth pressure transmitter 45#, a seventh temperature transmitter 46# and an eleventh thermometer 47# are also arranged on the pipeline between the lean solution transportation pump P-2 and the lean solution inlet of the heat exchanger E-1; and a lean solution outlet of the heat exchanger E-1 is communicated with a pipeline provided with an eleventh check valve V-26.
And a twelfth thermometer 48# and a ninth pressure gauge 49# are arranged on an outlet pipeline of the eleventh check valve V-26.
The top of the regeneration tower is provided with a safety valve V-27 for discharging when the pressure exceeds the limit.
The ethylene glycol regeneration method based on the ethylene glycol rich solution regeneration dehydration system in the deep sea natural gas exploitation process comprises the following steps:
step 1: in the initial state, valves in each system are in a closed state; firstly, opening a first stop valve V-1 and a first bypass stop valve V-2, starting a rich liquid transport pump P-1, detecting that the pressure in a pipe is stable by a first pressure transmitter 2# after a bypass loop between an ethylene glycol rich tank G-1 and the rich liquid transport pump P-1 is filled with ethylene glycol rich liquid, then opening a first electric valve V-4 through remote control, opening a first flow control valve V-5, simultaneously closing the first bypass stop valve V-2, and conveying the ethylene glycol rich liquid with the temperature of about 70 ℃ into a heat exchanger E-1;
step 2: through a heat exchanger E-1, heat exchange is carried out on qualified ethylene glycol barren solution with the temperature of 139 +/-5 ℃ output from a tower kettle of a regeneration tower T-1 and the ethylene glycol rich solution with the temperature of 70 ℃ in the step 1-1, the temperature of the ethylene glycol rich solution at a rich solution outlet of the heat exchanger E-1 reaches 85 +/-5 ℃ after heat exchange, the temperature of the ethylene glycol rich solution in the pipe is detected through a second temperature meter 6# and a first temperature transmitter 7#, a first flow control valve V-5 on a feeding pipe is controlled through a computer, the flow of the rich solution outlet of the heat exchanger E-1 is adjusted, and the temperature of the ethylene glycol rich solution at the rich solution outlet of the heat exchanger E-1 is kept stable; if an emergency situation happens suddenly, the first electric valve V-4 is directly and remotely closed, and the rich ethylene glycol solution is prevented from flowing in;
and step 3: ethylene glycol rich liquid with the temperature of 85 +/-5 ℃ output from a rich liquid outlet of a heat exchanger E-1 enters the middle of a regeneration tower T-1, the temperature and the pressure of a middle inlet of the regeneration tower T-1 are detected through a third thermometer 11# and a fourth pressure transmitter 26# in the middle of the regeneration tower T-1, a second flow control valve V-7 is controlled through a computer, the feeding flow of the regeneration tower T-1 is adjusted, the temperature and the pressure in the regeneration tower T-1 are kept stable, the pressure in the regeneration tower is kept at about 30 +/-10 KPa, if an emergency situation happens suddenly, a second electric valve V-8 is directly and remotely closed, and the input of the ethylene glycol rich liquid after heat exchange to the middle inlet of the regeneration tower T-1 is prevented;
and 4, step 4: the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ flows downwards along a second section packing layer in the regeneration tower T-1, the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ is continuously contacted with upward flowing hot steam generated by a vertical thermosiphon reboiler E-3 and continuously conducts heat, so that the temperature of the ethylene glycol rich solution is gradually increased, after the temperature value reaches 139 +/-5 ℃, heavy components (ethylene glycol) and light components (water vapor) in the ethylene glycol rich solution are separated, the heavy components (ethylene glycol) flow downwards into a tower kettle, the light components (water vapor) rise to the top of the tower and are discharged into a condenser through a gas phase outlet at the top of the regeneration tower T-1, after the light components (water vapor) are condensed to 30-40 ℃, about 3% -6% of condensed water flows back to the top of the regeneration tower T-1, and the ethylene glycol rich solution is purified conveniently;
and 5: the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ flows downwards to a tower kettle along a second section packing layer in the regeneration tower T-1, the ethylene glycol rich solution is input into a vertical thermosiphon reboiler E-3 from the tower kettle of the regeneration tower T-1 to be circularly heated, circulating power is derived from the density difference of two-phase fluid in the tower kettle of the regeneration tower T-1 and the vertical thermosiphon reboiler E-3, the vertical thermosiphon reboiler T-1 is heated by a heat medium, the shell pass of the heat medium is carried out, the tube pass of the ethylene glycol liquid is carried out, and the ethylene glycol liquid with the temperature of 139 +/-5 ℃ is input to the middle bottom of the regeneration tower T-1 from an outlet of the vertical thermosiphon reboiler E-3;
step 6, cooling a gas-phase product generated at the top of the regeneration tower T-1 to 30-40 ℃ through a condenser E-2, and storing condensed water in a condensed water tank G-2;
step 7, pumping a small amount of non-condensing gas in the condensate tank G-2 out of a gas phase outlet at the top of the condensate tank G-2 by a vacuum pump P-4 for discharging;
step 8, condensing a gas phase at the top of the regeneration tower T-1 and converting the gas phase into a liquid phase, so that in order to facilitate purification of an ethylene glycol rich liquid in the regeneration tower T-1, about 3-6% of condensed water needs to flow back to the top of the regeneration tower T-1 from one of two liquid phase outlets at the bottom of a condensed liquid tank G-2, detecting the temperature, the pressure and the flow of the reflux liquid through a fifth thermometer 18#, a third flow transmitter 19#, a third flow controller 20# and a fourth pressure gauge 21# on a pipeline connecting the condensed liquid tank G-2 and the top of the regeneration tower T-1, and then controlling a third flow control valve V-12 through a computer to adjust the flow of the reflux liquid so as to maintain the temperature and the pressure at the top of the regeneration tower T-1 to be stable;
step 9, connecting the other liquid phase outlet of the condensate tank G-2 with the condensate pump P-3, arranging a second liquid level transmitter 50# and a second liquid level controller 51# on the tank body of the condensate tank G-2, and opening the condensate pump P-3 to discharge the production water when the liquid level of the condensate tank G-2 exceeds the warning height;
step 10, detecting the ethylene glycol barren solution at the tower bottom of the regeneration tower T-1 by a first density display 29#, and opening a barren solution conveying pump P-2 for conveying after the concentration of the ethylene glycol reaches more than 95%;
step 11, conveying the qualified glycol solution to a lean solution inlet of a heat exchanger E-1, and exchanging heat with a glycol rich solution;
and 12, after the ethylene glycol barren solution exchanges heat with the ethylene glycol rich solution in the heat exchanger E-1, discharging the ethylene glycol barren solution with the temperature of 95 +/-5 ℃ into a desalting system from a barren solution outlet of the heat exchanger E-1.
As shown in fig. 2, the temperature of the rich liquid outlet of the heat exchanger E-1 is controlled to maintain the temperature of the rich liquid outlet of the heat exchanger E-1 at the set value of the temperature of the rich liquid outlet of 85 ± 5 ℃, the first temperature transmitter 7# on the rich liquid outlet pipeline of the heat exchanger E-1 is set with an over-temperature alarm and an under-temperature alarm, and when the temperature is not within the normal range and the above alarms are triggered, the following processing is performed according to the following principle:
when the temperature of the rich liquid outlet of the heat exchanger E-1 is lower than the set temperature and is too low, and the triggering temperature is too low to alarm, if the heat exchanger E-1 is not started, the heat exchanger E-1 is started;
if the heat exchanger E-1 is working at the moment, but the temperature of the barren liquor inlet of the heat exchanger E-1 is too low and does not reach the set temperature value (139 +/-5 ℃) and the heat exchange performance of the heat exchanger E-1 cannot meet the requirement, the rich liquor outlet of the heat exchanger E-1 is opened after the temperature of the tower kettle of the regeneration tower T-1 reaches the set temperature value (139 +/-5 ℃);
if the liquid level of the tower kettle is too high and the temperature of the tower kettle of the regeneration tower T-1 cannot reach the set temperature value (139 +/-5 ℃), reducing the opening degrees of the first flow control valve V-5 and the second flow control valve V-7, continuously reducing the liquid level of the tower kettle along with the continuous rectification of the regeneration tower T-1, and inputting the glycol barren solution in the tower kettle to a barren solution inlet of a heat exchanger E-1 after the temperature of an outlet of a vertical thermosyphon reboiler E-3 meets the requirement of 139 +/-5 ℃, and simultaneously opening the opening degrees of the first flow control valve V-5 and the second flow control valve V-7 to be normal;
if the temperature of the tower kettle meets the requirement of a set temperature value (139 +/-5 ℃), controlling the opening degrees of a first flow control valve V-5 and a second flow control valve V-7, and controlling the liquid-phase feeding temperature by controlling the flow;
when the temperature of a rich liquid outlet of the heat exchanger E-1 is too high, and the triggering temperature is too high for alarming, if the temperature of a lean liquid in a tower kettle of the regeneration tower T-1 is too high, the opening degrees of the first flow control valve V-5 and the second flow control valve V-7 are adjusted to be the maximum, and meanwhile, the opening degree of the third flow control valve V-12 is opened to be within an allowed range.
As shown in fig. 3, tower cauldron liquid level transmitter sets up the too high warning of liquid level limit, the too high warning of liquid level, the liquid level is crossed the low warning and the liquid level limit is crossed the low warning, when the liquid level is not in normal range, when leading to having triggered above reporting to the police, handles according to following mode:
if the liquid level at the tower bottom in the regeneration tower is too high and exceeds a preset limit height value, so that the liquid level limit at the tower bottom is triggered to alarm too high, cutting off a second electric valve V-8 of the feeding pipeline and a third electric valve V-13 of the return pipeline, and simultaneously judging whether flooding occurs; if the flooding occurs, processing according to a flooding processing method;
if no flooding occurs and the barren solution in the tower kettle meets the production requirement, increasing the discharge amount of the tower kettle, and opening a barren solution transport pump P-2 to the maximum so as to adjust the liquid level of the tower kettle;
if the quality of the barren solution in the tower kettle is not qualified, stopping discharging the tower kettle solution, opening a fourth flow opening valve V-18 at the inlet of a reboiler to the maximum amount within the allowable range, improving the rectification efficiency of the regeneration tower, separating out light components (water) until the tower kettle barren solution is qualified and discharged, and enabling the liquid level in the tower kettle to be at a normal level; after the liquid level of the tower kettle is normal, opening a second electric valve V-8 and a third electric valve V-13 for normal feeding, and opening the opening of a fourth flow opening valve V-18 to a set normal amount;
when the alarm of the overhigh liquid level limit is triggered, an operator intervenes in the treatment.
If the liquid level at the tower kettle in the regeneration tower causes triggering of an over-high liquid level alarm, judging whether flooding occurs or not, if flooding occurs, processing according to a flooding processing method, if flooding does not occur, observing a density display 29# and a seventh thermometer 32# to know the concentration and the temperature of lean liquid in the tower kettle, if the ethylene glycol lean liquid in the tower kettle meets production requirements, increasing the discharge capacity of the tower kettle, and opening the working efficiency of a lean liquid transport pump P-2 to the maximum, so that the liquid level of the tower kettle is adjusted;
if the quality of the barren solution in the tower kettle is not qualified, stopping discharging the tower kettle solution; opening the first flow control valve V-5, the second flow control valve V-7 and the third flow control valve V-12 to the lowest degree, reducing the feeding flow, opening the fourth flow opening valve V-18 of the reboiler to the maximum amount within the allowable range, increasing the rectification efficiency of the regeneration tower, separating out light components (water), ensuring that the barren solution at the tower kettle is qualified and discharged, and enabling the liquid level in the tower kettle to be at the normal level; opening the opening degrees of a first flow control valve V-5, a second flow control valve V-7, a third flow control valve V-12 and a fourth flow opening valve V-18 to set normal quantities after the liquid level of the tower kettle is normal;
if the liquid level at the bottom of the regeneration tower T-1 is too low and the liquid level too low alarm is triggered, judging whether the liquid level is caused by the occurrence of flooding, and if the liquid level is caused by the occurrence of flooding, processing according to a flooding processing method; if the flooding does not occur, stopping discharging the tower kettle liquid, and judging whether the ethylene glycol rich liquid feeding liquid in the regeneration tower is insufficient due to the fact that whether a feeding loop is cut off or not;
if the liquid phase feeding loop is cut off at this time, the second electric valve V-8 on the feeding loop is firstly opened; if the liquid phase feeding loop is not cut off at the moment, and the opening degree of a second flow control valve V-7 in the feeding loop reaches the maximum, the reflux quantity at the top of the tower is increased at the same time, the opening degree of a third flow control valve V-12 reaches the maximum, and when the liquid level of the tower kettle is at a normal level, the opening degrees of the second flow control valve V-7 and the third flow control valve V-12 are opened to be normal;
if the liquid level at the tower kettle in the regeneration tower T-1 is lower than a preset limit over-low liquid level value, triggering a liquid level limit over-low alarm, immediately stopping the discharge of the tower kettle liquid, and simultaneously judging whether the liquid level is due to the occurrence of flooding, if so, processing the liquid level according to a flooding processing method; if the flooding does not occur, closing the fourth electric valve V-19 and closing the vertical thermosiphon reboiler E-3; judging whether the feeding is insufficient due to the fact that a feeding loop is cut off, and if so, opening a second electric valve V-8;
if the feed loop is not cut off, opening degrees of the first flow control valve V-5, the second flow control valve V-7 and the third flow control valve V-12 are opened to the maximum; the liquid level of the tower kettle is gradually increased, and when the liquid level is higher than the set lowest liquid level, a fourth electric valve V-19 is opened to restart the vertical thermosiphon reboiler E-3; opening the opening degrees of the first flow control valve V-5, the second flow control valve V-7 and the third flow control valve V-12 to normal values when the liquid level of the tower kettle reaches a set normal value;
when the alarm of the liquid level limit is triggered to be too low, an operator intervenes to process.
As shown in fig. 4, the pressure transmitter of the T-1 tower kettle of the regeneration tower is provided with a pressure limit too low alarm, a pressure too high alarm and a pressure limit too high alarm, and when the pressure in the tower kettle of the regeneration tower is not within a normal range, which causes triggering of a corresponding alarm, the pressure transmitter is processed as follows:
when the pressure of the tower kettle is continuously overhigh and the alarm of overhigh pressure limit (200KPa) is triggered, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, temporarily closing the fourth electric valve V-19 and stopping the discharge of the tower kettle by cutting off the seventh electric valve V-28, opening the second flow control valve V-7 and the third flow control valve V-12 to the maximum, opening the fourth electric valve V-19 and opening the second flow control valve V-7 and the third flow control valve V-12 to the normal after the pressure of the tower kettle is recovered to a set normal level, and opening the seventh electric valve V-28 to discharge qualified glycol from the tower kettle;
when the pressure of a tower kettle is overhigh to trigger overhigh pressure (70KPa) alarm, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the opening degree of the fourth flow control valve V-18 to the minimum allowable value, stopping the discharge of the tower kettle by cutting off the seventh electric valve V-28, opening the opening degrees of the second flow control valve V-7 and the third flow control valve V-12 to the maximum, opening the seventh electric valve V-28 after the pressure is recovered to the set normal value, discharging qualified ethylene glycol from the tower kettle, opening the fourth electric valve V-19, and opening the opening degrees of the second flow control valve V-7 and the third flow control valve V-12 to the normal value;
when the pressure in the tower kettle is too low and the pressure too low (15KPa) alarm is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the second flow control valve V-7 and the third flow control valve V-12 to the minimum, opening the fourth flow control valve V-18 to the maximum allowable value, and opening the fourth flow control valve V-18, the second flow control valve V-7 and the third flow control valve V-12 to the normal value after the pressure is recovered to the set normal value (30 KPa);
when the pressure in the tower kettle is low enough to trigger the alarm of too low pressure limit (5KPa), firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the opening degree of the fourth flow control valve V-18 to the maximum allowable value, closing the first electric valve V-4, the second electric valve V-8 and the third electric valve V-13 so as to cut off feeding, opening the first electric valve V-4, the second electric valve V-8 and the third electric valve V-13 after the pressure is recovered to a normal level, and opening the opening degree of the fourth flow control valve V-18 to the normal level;
when the alarm of the overhigh pressure limit is triggered, an operator intervenes to process.
As shown in fig. 5, the second pressure transmitter 12# at the top of the regeneration tower T-1 is provided with a pressure limit too low alarm, a pressure too high alarm and a pressure limit too high alarm, and when the pressure in the top of the regeneration tower T-1 is not within a normal range, which causes triggering of a corresponding alarm, the following processing is performed:
when the pressure at the top of the tower is continuously too low and the alarm of too low pressure limit (1KPa) is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, temporarily closing the gas phase outlet at the top of the tower and the third electric valve V-13, and opening the gas phase outlet at the top of the tower and the third electric valve V-13 after the pressure is recovered to a set normal level;
when the pressure at the top of the tower is too low, so that the alarm of too low pressure (6KPa) is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the opening degree of the third flow control valve V-12 to the minimum allowable value, and opening the opening degree of the third flow control valve V-12 to a set normal value after the pressure is recovered to a certain level;
when the pressure at the top of the tower is too high, so that the alarm of the pressure is triggered to be too high (30KPa), opening the third flow control valve V-12 to the maximum allowable value, and opening the third flow control valve V-12 to the normal value after the pressure is recovered to the normal level (15 KPa);
when the pressure in the tower top is continuously overhigh and the alarm of overhigh pressure limit (200KPa) is triggered, the safety pressure relief valve V-27 at the tower top is automatically opened and is automatically closed after the pressure is restored to a normal level;
when the alarm of the overhigh pressure limit is triggered, an operator intervenes to process.
The control of the condensation reflux temperature and flow at the top of the tower and the liquid level in the condensate tank is as follows:
when the fifth thermometer 18# detects that the temperature of the reflux is overhigh (80 ℃) and triggers overhigh temperature alarm, the flow of the cooling liquid in the condenser E-2 is increased through a third flow control valve V-12 until the temperature of the reflux is in a normal level;
when the fifth temperature table 18# detects that the temperature of the reflux is too low (30 ℃) and triggers a too low temperature alarm, the flow of the cooling liquid in the condenser E-2 is reduced through a third flow control valve V-12 until the temperature of the reflux is at a normal level;
when the second liquid level transmitter 50# detects that the liquid level of the condensate tank G-2 is too high, the liquid in the condensate tank G-2 is directly discharged by the condensate pump P-3.
In the operation process of the regeneration dehydration system, when liquid phase feeding, tower top reflux and tower kettle discharging are in normal conditions, the liquid level of the tower kettle is too low, the outlet temperature of the vertical thermosiphon reboiler is more than a set value (139 +/-5 ℃), the pressure difference between the tower top and the tower kettle is more than a set value, the temperature of the middle part of the tower is increased, and the temperature of the tower top is reduced, the occurrence of flooding is judged, and the flooding treatment is as follows: adjusting a second flow control valve V-7 to reduce or suspend the rich liquid feeding of the regeneration tower T-1, adjusting the opening degree of a third flow control valve V-12 to ensure the reflux of the tower top so as to return the glycol liquid at the tower top to the tower again, and keeping the liquid level height of the tower kettle not to be reduced any more; and (3) keeping the steam amount, and eliminating the accumulated liquid in the packing in the tower kettle in an evaporation mode until the heat penetrates through the packing to enable the pressure difference to fall back to a set normal level (10 +/-5 KPa), and then reestablishing the gas-liquid balance.
The above-mentioned embodiments are merely illustrative of the principles and effects of the present invention, and some embodiments may be used, not restrictive; it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications belong to the protection scope of the present invention.

Claims (10)

1. The utility model provides a rich liquid regeneration dewatering system of ethylene glycol in deep sea natural gas exploitation in-process which characterized in that: the system comprises an ethylene glycol-rich tank for storing an ethylene glycol-rich solution from an upstream pretreatment system, wherein the ethylene glycol-rich tank is connected with a rich liquid transport pump through a pipeline, a first stop valve is installed on the pipeline between the ethylene glycol-rich tank and the rich liquid transport pump, and a first temperature gauge and a first pressure transmitter are installed on the pipeline between the ethylene glycol-rich tank and the first stop valve; the output outlet of the rich liquid transport pump is connected with a three-way valve, and one way of the three-way valve is communicated to a rich liquid inlet of the heat exchanger through a pipeline; the other path of the three-way valve is connected with a first bypass stop valve through a pipeline and is connected to the feeding end of the first stop valve to form a bypass loop; a first check valve, a first electric valve and a first flow control valve are sequentially arranged on a pipeline between the rich liquid transport pump and the rich liquid inlet of the heat exchanger, and a first flow transmitter, a first flow controller and a first pressure gauge are arranged on the pipeline between the rich liquid inlet of the heat exchanger and the first flow control valve;
the heat exchanger rich liquid outlet is communicated with the middle part of the regeneration tower through a pipeline, a second check valve, a second flow control valve and a second electric valve are sequentially arranged on the pipeline between the heat exchanger rich liquid outlet and the regeneration tower, and a second thermometer, a first temperature transmitter, a second flow control instrument and a second pressure gauge are arranged on the pipeline between the second flow control valve and the second electric valve;
two liquid phase outlets are arranged on a tower kettle of the regeneration tower, a gas phase outlet is arranged at the top of the regeneration tower, the gas phase outlet at the top of the regeneration tower is communicated with an inlet of a condenser through a pipeline, one liquid phase outlet on the tower kettle of the regeneration tower is communicated with a barren liquor inlet of a heat exchanger through a barren liquor transport pump and a pipeline, the other liquid phase outlet on the tower kettle of the regeneration tower is communicated with an inlet of a vertical thermosyphon reboiler through a pipeline, and the outlet of the vertical thermosyphon reboiler is communicated with the middle part of the regeneration tower through a pipeline to form a circulating heating;
the upper part of the regeneration tower is provided with a second pressure transmitter, a first pressure controller, a fifth pressure gauge, a sixth temperature gauge and a third temperature transmitter which are used for monitoring the temperature and the pressure of the upper part of the regeneration tower in real time so as to adjust the opening degree of a third flow control valve; the middle part of the regeneration tower is provided with a third temperature meter and a fourth pressure transmitter which are used for monitoring the temperature and the pressure of the middle part of the regeneration tower, namely the feeding position of the regeneration tower in real time so as to adjust the opening of the second flow control valve; the bottom of the regeneration tower is provided with a first liquid level transmitter, a first liquid level controller, a first density display, a sixth pressure gauge, a third pressure controller, a seventh thermometer, a fourth temperature transmitter and a fifth pressure transmitter, and the first liquid level transmitter, the first liquid level controller, the first density display, the sixth pressure gauge, the third pressure controller, the seventh thermometer, the fourth temperature transmitter and the fifth pressure transmitter are used for monitoring the temperature, the pressure, the liquid level and the ethylene glycol concentration at the bottom of the regeneration tower in real time so as to adjust the opening degrees of the second flow control valve;
a pipeline between a tower top gas phase outlet of the regeneration tower and a condenser inlet is provided with a second pressure controller, a fourth thermometer, a third pressure gauge and a third one-way valve; the outlet of the condenser is communicated with the condensate tank through a pipeline, and a fourth check valve and a second temperature transmitter are arranged on the pipeline between the outlet of the condenser and the condensate tank; the condensate tank is provided with two liquid phase outlets positioned at the bottom of the tank and a gas phase outlet positioned at the top of the tank, the gas phase outlet at the top of the condensate tank is connected with the vacuum pump through a pipeline, and a second stop valve is arranged between the outlet at the top of the condensate tank and the vacuum pump through a pipeline;
one of two liquid phase outlets of the condensate tank is connected with the upper part of the regeneration tower through a pipeline to provide reflux required by rectification, a fifth one-way valve, a third flow control valve and a third electric valve are arranged on a pipeline between the condensate tank and the regeneration tower, and a third pressure transmitter, a fifth thermometer, a third flow transmitter, a third flow control instrument and a fourth pressure gauge are arranged on a pipeline between the condensate tank and the regeneration tower and used for monitoring the flow, the temperature and the pressure of the reflux at the top of the tower in real time to adjust the opening sizes of the second flow control valve, the third flow control valve and the fourth flow control valve; a liquid phase outlet of the other condensate tank is communicated with a condensate pump inlet through a pipeline, a fifth one-way valve is arranged on a pipeline between the condensate tank and the condensate pump inlet, a condensate pump outlet is communicated with a seventh one-way valve through a pipeline, and a second liquid level transmitter, a second liquid level controller, a thirteenth temperature gauge and a tenth pressure gauge are further arranged on a condensate tank body so as to adjust the condensate pump according to the measured liquid level of the condensate tank;
the tower kettle of the regeneration tower is communicated with an inlet of the vertical thermosiphon reboiler through a pipeline, an eighth one-way valve, a fourth flow control valve and a fourth electric valve are arranged on the pipeline between the tower kettle of the regeneration tower and the inlet of the vertical thermosiphon reboiler, and a seventh pressure gauge, an eighth thermometer, a fifth temperature transmitter, a fourth flow transmitter and a fourth flow control instrument are further arranged on the pipeline between the tower kettle of the regeneration tower and the inlet of the vertical thermosiphon reboiler and used for monitoring the temperature, the pressure and the flow in the pipeline between the tower kettle of the regeneration tower and the inlet of the vertical thermosiphon reboiler; an outlet of the vertical thermosyphon reboiler is communicated with the bottom of the regeneration tower through a pipeline, a fifth electric valve and a ninth one-way valve are arranged between the outlet of the vertical thermosyphon reboiler and the bottom of the regeneration tower, and an eighth pressure gauge, a sixth temperature transmitter, a first temperature controller and a ninth thermometer are further arranged between the outlet of the vertical thermosyphon reboiler and the bottom of the regeneration tower for monitoring the temperature and the pressure in the pipeline in real time so as to adjust the opening degrees of the second flow control valve, the third flow control valve and the fourth flow control valve;
the regeneration tower kettle is communicated with an inlet of a barren liquor transport pump through a pipeline, a seventh electric valve and a third stop valve are sequentially installed on the pipeline between the regeneration tower kettle and the inlet of the barren liquor transport pump, an outlet of the barren liquor transport pump is connected with a three-way valve, one path of the outlet of the three-way valve is connected with a barren liquor inlet of a heat exchanger through a pipeline, and the other path of the outlet of the three-way valve is connected with a liquid inlet of the third stop valve through a pipeline provided with a second bypass stop; a tenth check valve and a sixth electric valve are sequentially arranged on a pipeline between the lean solution transport pump and the lean solution inlet of the heat exchanger, and a sixth pressure transmitter, a seventh temperature transmitter and an eleventh thermometer are further arranged on the pipeline between the lean solution transport pump and the lean solution inlet of the heat exchanger; and a lean solution outlet of the heat exchanger is communicated with a pipeline provided with an eleventh check valve.
2. The deep sea natural gas mining process ethylene glycol rich liquid regeneration dehydration system of claim 1, characterized in that: and a twelfth thermometer and a ninth pressure gauge are arranged on an outlet pipeline of the eleventh check valve.
3. The deep sea natural gas mining process ethylene glycol rich liquid regeneration dehydration system of claim 1, characterized in that: and a safety relief valve for discharging when the pressure at the top of the regeneration tower is too high is arranged at the top of the regeneration tower.
4. The ethylene glycol regeneration method based on the ethylene glycol rich solution regeneration dehydration system in the deep sea natural gas exploitation process of any one of the claims 1 to 3, comprising the following steps:
step 1: in the initial state, valves in each system are in a closed state; the method comprises the steps that firstly, a first stop valve and a first bypass stop valve are opened, a rich liquid transport pump is started, when a bypass loop between an ethylene glycol-rich tank and the rich liquid transport pump is filled with ethylene glycol rich liquid, a first pressure transmitter detects that the pressure in the pipe is stable, then a first electric valve is opened through remote control, a first flow control valve is opened, the first bypass stop valve is closed, and the ethylene glycol rich liquid with the temperature of about 70 ℃ is transported into a heat exchanger;
step 2: carrying out heat exchange on the qualified ethylene glycol barren solution with the temperature of 139 +/-5 ℃ output from the tower kettle of the regeneration tower and the ethylene glycol rich solution with the temperature of 70 ℃ in the step 1 through a heat exchanger, detecting the temperature of the ethylene glycol rich solution in the pipe through a second thermometer and a first temperature transmitter after the heat exchange, controlling a first flow control valve on a feeding pipe through a computer, adjusting the flow of the rich solution outlet of the heat exchanger, and maintaining the temperature of the ethylene glycol rich solution at the rich solution outlet of the heat exchanger to be stable;
and step 3: the ethylene glycol rich solution with the temperature of 85 plus or minus 5 ℃ output from the rich solution outlet of the heat exchanger enters the middle part of the regeneration tower, the temperature and the pressure of the inlet in the middle part of the regeneration tower are detected by a third temperature gauge and a fourth pressure transmitter in the middle part of the regeneration tower, the feeding flow of the regeneration tower is adjusted by controlling a second flow control valve by a computer, the temperature and the pressure in the regeneration tower are maintained to be stable, the pressure in the regeneration tower is kept at 30 plus or minus 10KPa,
and 4, step 4: the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ flows downwards along a second section packing layer in the regeneration tower, the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ is continuously contacted with upward flowing hot steam generated by a vertical thermosiphon reboiler and continuously conducts heat, so that the temperature of the ethylene glycol rich solution is gradually increased, after the temperature reaches 139 +/-5 ℃, heavy components and light components in the ethylene glycol rich solution are separated, the heavy components flow downwards into a tower kettle, the light components rise to the top of the tower and are discharged into a condenser through a gas phase outlet at the top of the regeneration tower;
and 5: the ethylene glycol rich solution with the temperature of 85 +/-5 ℃ flows downwards to a tower kettle along a second section packing layer in the regeneration tower, the ethylene glycol rich solution is input into a vertical thermosiphon reboiler from the tower kettle of the regeneration tower for circulating heating, circulating power is derived from the liquid level of the tower kettle of the regeneration tower and the density difference of two-phase fluid in the vertical thermosiphon reboiler, the vertical thermosiphon reboiler is heated by a heat medium, the heat medium flows through a shell pass, the ethylene glycol liquid flows through a tube pass, and the ethylene glycol liquid with the temperature of 139 +/-5 ℃ is input into the middle bottom of the regeneration tower from an outlet of the vertical thermosiphon reboiler;
step 6, cooling a gas-phase product generated at the top of the regeneration tower to 30-40 ℃ through a condenser, and feeding condensed water into a condensed water tank for storage;
step 7, pumping out a small amount of non-condensable gas in the condensate tank through a gas phase outlet at the top of the condensate tank by a vacuum pump and discharging;
step 8, condensing the gas phase at the top of the regeneration tower, converting the gas phase into a liquid phase, and refluxing 3-6% of condensed water from a condensate tank to the top of the regeneration tower; the flow of the reflux liquid of the third flow control valve is controlled by the temperature, the pressure and the flow of the reflux liquid on a pipeline connecting the condensate tank and the top of the regeneration tower so as to maintain the temperature and the pressure at the top of the regeneration tower to be stable;
step 9, when the liquid level of the condensate tank exceeds the warning height of the second liquid level controller, opening a condensate pump to discharge condensate in the condensate tank;
step 10, detecting the ethylene glycol barren solution at the tower bottom of the regeneration tower to be qualified through a first density display, and opening a barren solution conveying pump to convey the ethylene glycol barren solution after the concentration of the ethylene glycol reaches above;
step 11, conveying the qualified glycol solution to a lean solution inlet of a heat exchanger to exchange heat with a glycol rich solution;
and 12, after the ethylene glycol barren solution exchanges heat with the ethylene glycol rich solution in the heat exchanger, discharging the ethylene glycol barren solution at the temperature of 95 +/-5 ℃ from a barren solution outlet of the heat exchanger so as to send the ethylene glycol barren solution to a desalination system connected with the heat exchanger.
5. The method for regenerating ethylene glycol of an ethylene glycol rich solution regeneration dehydration system in the process of deep sea natural gas exploitation according to claim 4, characterized in that: controlling the temperature of the rich liquid outlet of the heat exchanger to keep the temperature of the rich liquid outlet of the heat exchanger to be maintained at a set value of the temperature of the rich liquid outlet of 85 +/-5 ℃, setting overhigh temperature alarm and overlow temperature alarm by a first temperature transmitter on a rich liquid outlet pipeline of the heat exchanger, and processing the temperature alarm according to the following modes when the temperature is not within a normal range and the alarm is triggered:
when the temperature of the rich liquid outlet of the heat exchanger is lower than the set temperature and is too low, and the triggering temperature is too low to alarm, if the heat exchanger is not started, the heat exchanger is started;
if the heat exchanger is working at the moment, but the temperature of the barren solution inlet of the heat exchanger is too low and does not reach the set temperature value, so that the heat exchange performance of the heat exchanger cannot meet the requirement, the rich solution outlet of the heat exchanger is opened after the temperature of the tower kettle of the regeneration tower reaches the set temperature value;
if the liquid level of the tower kettle is too high and the temperature of the tower kettle of the regeneration tower cannot reach the set temperature value, reducing the opening degrees of the first flow control valve and the second flow control valve, continuously rectifying along with the regeneration tower, continuously reducing the liquid level of the tower kettle, inputting the glycol barren solution in the tower kettle to a barren solution inlet of a heat exchanger after the outlet temperature of the vertical thermosiphon reboiler meets the requirement, and simultaneously opening the opening degrees of the first flow control valve and the second flow control valve to be normal;
if the temperature of the tower kettle meets the requirement of a set temperature value, controlling the opening degrees of the first flow control valve and the second flow control valve, and controlling the liquid-phase feeding temperature by controlling the flow;
when the temperature of a rich liquid outlet of the heat exchanger is too high, which causes the triggering of an over-high temperature alarm, if the temperature of a lean liquid in a tower kettle of the regeneration tower is too high, the opening degrees of the first flow control valve and the second flow control valve are adjusted to be the maximum, and meanwhile, the opening degree of the third flow control valve is opened to be within an allowable range.
6. The method for regenerating ethylene glycol of an ethylene glycol rich solution regeneration dehydration system in the process of deep sea natural gas exploitation according to claim 4, characterized in that: tower cauldron liquid level changer sets up liquid level limit too high warning, liquid level and crosses low warning and liquid level limit too low, and when the liquid level was not in normal range, when having leaded to triggering above warning, handles according to following mode:
if the liquid level at the tower kettle in the regeneration tower is too high and exceeds a preset limit height value, so that the liquid level limit at the tower kettle is triggered to alarm too high, a second electric valve of the feeding pipeline and a third electric valve of the return pipeline are cut off, and whether flooding occurs or not is judged; if the flooding occurs, processing according to a flooding processing method;
if no flooding occurs and the barren solution in the tower kettle meets the production requirement, increasing the discharge amount of the tower kettle, and opening a barren solution transport pump to the maximum so as to adjust the liquid level of the tower kettle;
if the quality of the barren solution in the tower kettle is not qualified, stopping discharging the tower kettle solution, opening the opening of a fourth flow opening valve at the inlet of a reboiler to the maximum amount within an allowable range, improving the rectification efficiency of the regeneration tower, separating out light components until the barren solution in the tower kettle is qualified and discharged, and enabling the liquid level in the tower kettle to be at a normal level; opening a second electric valve and a third electric valve for normal feeding after the liquid level of the tower kettle is normal, and opening the opening degree of a fourth flow opening valve to a set normal amount;
if the liquid level at the tower kettle in the regeneration tower causes triggering of an over-high liquid level alarm, judging whether flooding occurs or not, if flooding occurs, processing according to a flooding processing method, if flooding does not occur, observing a density display and a seventh thermometer to know the concentration and temperature of the barren solution in the tower kettle, if production requirements are met, increasing the discharge capacity of the tower kettle, and opening the working efficiency of a barren solution transport pump to the maximum, so that the liquid level of the tower kettle is adjusted;
if the quality of the barren solution in the tower kettle is not qualified, stopping discharging the tower kettle solution; opening the first flow control valve, the second flow control valve and the third flow control valve to the minimum, reducing the feeding flow, opening the fourth flow opening valve of the reboiler to the maximum within the allowable range, increasing the rectification efficiency of the regeneration tower, separating out light components, ensuring that the barren solution in the tower kettle is qualified and discharged, and ensuring that the liquid level in the tower kettle is at the normal level; opening degrees of a first flow control valve, a second flow control valve, a third flow control valve and a fourth flow opening valve to set normal quantities after the liquid level of the tower kettle is normal;
if the liquid level at the tower bottom of the regeneration tower is too low, triggering an alarm of too low liquid level, judging whether the liquid level is caused by the occurrence of flooding, and if so, processing according to a flooding processing method; if the flooding does not occur, stopping discharging the tower kettle liquid, and judging whether the ethylene glycol rich liquid feeding liquid in the regeneration tower is insufficient due to the fact that whether a feeding loop is cut off or not;
if the liquid phase feeding loop is cut off at this time, a second electric valve on the feeding loop is opened firstly; if the liquid phase feeding loop is not cut off at the moment, and the opening degree of a second flow control valve in the feeding loop reaches the maximum, the reflux quantity at the top of the tower is increased at the same time, the opening degree of a third flow control valve reaches the maximum, and when the liquid level of the tower kettle is at a normal level, the opening degrees of the second flow control valve and the third flow control valve are opened to be normal;
if the liquid level at the tower kettle in the regeneration tower is lower than a preset limit low liquid level value, triggering a liquid level limit low alarm, immediately stopping the discharge of the tower kettle liquid, and simultaneously judging whether the liquid level is due to the occurrence of flooding, if so, processing the liquid level according to a flooding processing method; if the liquid flooding does not occur, closing the fourth electric valve, and closing the vertical thermosiphon reboiler; judging whether the feeding is insufficient due to the fact that the feeding loop is cut off, and if so, opening a second electric valve;
if the feed loop is not cut off, opening the first flow control valve, the second flow control valve and the third flow control valve to the maximum; the liquid level of the tower kettle is gradually increased, and when the liquid level is higher than the set lowest liquid level, a fourth electric valve is opened to restart the vertical thermosiphon reboiler; and opening the opening degrees of the first flow control valve, the second flow control valve and the third flow control valve to normal values when the liquid level of the tower kettle reaches a set normal value.
7. The method for regenerating ethylene glycol of an ethylene glycol rich solution regeneration dehydration system in the process of deep sea natural gas exploitation according to claim 6, characterized in that: the pressure transmitter of regeneration tower cauldron has set up that pressure limit crosses low warning, pressure and has crossed low warning, pressure and report to the police and pressure limit is too high, and when regeneration tower cauldron internal pressure is not in normal range, when having leaded to trigger corresponding warning, handles according to following mode:
when the pressure of the tower kettle is continuously overhigh to trigger an overhigh pressure limit value and give an alarm, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, temporarily closing the fourth electric valve and stopping the discharge of the tower kettle by cutting off the seventh electric valve, opening the second flow control valve and the third flow control valve to the maximum, opening the fourth electric valve and opening the second flow control valve and the third flow control valve to the normal after the pressure of the tower kettle is recovered to a set normal level, and opening the seventh electric valve to discharge qualified ethylene glycol from the tower kettle;
when the pressure of the tower kettle is too high and the pressure too high alarm is triggered, firstly, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the opening degree of the fourth flow control valve to the minimum allowable value, stopping discharging from the tower kettle by cutting off the seventh electric valve, opening the openings of the second flow control valve and the third flow control valve to the maximum, opening the seventh electric valve to discharge qualified glycol from the tower kettle after the pressure is recovered to a set normal value, opening the fourth electric valve, and opening the opening degrees of the second flow control valve and the third flow control valve to the normal value;
when the pressure in the tower kettle is too low and the alarm of too low pressure is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if flooding does not occur, opening the second flow control valve and the third flow control valve to the minimum, opening the fourth flow control valve to the maximum, and opening the fourth flow control valve, the second flow control valve and the third flow control valve to the normal value after the pressure is recovered to the set normal value;
when the pressure in the tower kettle is low enough to trigger the alarm of too low pressure limit, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, opening the opening degree of the fourth flow control valve to the maximum allowable value, closing the first electric valve, the second electric valve and the third electric valve so as to cut off the feeding, opening the first electric valve, the second electric valve and the third electric valve after the pressure is recovered to a normal level, and opening the opening degree of the fourth flow control valve to a normal value.
8. The method for regenerating ethylene glycol of an ethylene glycol rich solution regeneration dehydration system in the process of deep sea natural gas exploitation according to claim 7, characterized in that: the second pressure transmitter on the top of the regeneration tower is provided with a pressure limit over-low alarm, a pressure over-high alarm and a pressure limit over-high alarm, and when the pressure in the top of the regeneration tower is not in a normal range, the regeneration tower triggers a corresponding alarm, and the regeneration tower is processed according to the following modes:
when the pressure at the top of the tower is continuously too low and the alarm of too low pressure limit is triggered, firstly judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, temporarily closing the gas phase outlet at the top of the tower and the third electric valve, and opening the gas phase outlet at the top of the tower and the third electric valve after the pressure is recovered to a set normal level;
when the pressure at the top of the tower is too low, and the pressure too low alarm is triggered, firstly, judging whether the flooding occurs or not, and if the flooding occurs, processing according to a flooding processing method; if the flooding does not occur, opening the third flow control valve to the minimum allowable value, and after the pressure is recovered to a certain level, opening the third flow control valve to a set normal value;
when the pressure at the tower top is too high, so that the over-pressure alarm is triggered, opening the third flow control valve to the maximum allowable value, and after the pressure is restored to the normal level, opening the third flow control valve to the normal value;
when the pressure in the tower top is continuously overhigh and the alarm of overhigh pressure limit is triggered, the safety pressure relief valve on the tower top is automatically opened and is automatically closed after the pressure is restored to a normal level.
9. The method for regenerating ethylene glycol of an ethylene glycol rich solution regeneration dehydration system in the process of exploiting deep sea natural gas according to any of claims 6 to 8, characterized in that: in the operation process of the regeneration dehydration system, when liquid phase feeding, tower top reflux and tower kettle discharging are in normal conditions, the liquid level of the tower kettle is too low, the outlet temperature of the vertical thermosiphon reboiler is greater than a set value, the pressure difference between the tower top and the tower kettle is greater than a set value, the temperature of the middle part of the tower is increased, and the temperature of the tower top is reduced to more than two conditions, the occurrence of flooding is judged, and the flooding treatment is as follows: adjusting a second flow control valve to reduce or suspend the rich liquid feeding of the regeneration tower, adjusting the opening degree of a third flow control valve, ensuring the reflux of the tower top to return the ethylene glycol liquid at the tower top to the tower again, and keeping the liquid level height of the tower kettle not to be reduced any more; and (4) keeping the steam amount, and eliminating accumulated liquid in the packing in the tower kettle in an evaporation mode until the heat penetrates through the packing to enable the pressure difference to fall back to a set normal level and reestablish the gas-liquid balance.
10. The method for regenerating ethylene glycol of an ethylene glycol rich solution regeneration dehydration system in the process of deep sea natural gas exploitation according to claim 7, characterized in that:
the control of the condensation reflux temperature and flow at the top of the tower and the liquid level in the condensate tank is as follows:
when the fifth thermometer detects that the temperature of the reflux is too high and triggers an over-temperature alarm, the flow of the cooling liquid in the condenser is increased through a third flow control valve until the temperature of the reflux liquid is at a normal level;
when the fifth thermometer detects that the temperature of the reflux is too low and triggers a too low temperature alarm, the flow of the cooling liquid in the condenser is reduced through a third flow control valve until the temperature of the reflux is at a normal level;
when the second liquid level transmitter detects that the liquid level of the condensate tank is too high, the condensate pump directly discharges the liquid in the condensate tank.
CN202011030011.6A 2020-09-27 2020-09-27 Ethylene glycol rich solution regeneration dehydration system and method in deep sea natural gas exploitation process Pending CN112107876A (en)

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