阅读说明：本技术 一种天然气净化系统 (Natural gas purification system ) 是由 黄业千 李长河 黄辉 李伟 王荣娟 于 2019-09-03 设计创作，主要内容包括：本发明提出了一种天然气净化系统,包括天然气输入管线、天然气输出管线、设置在天然气输入管线与脱水气输出管线之间的能选择性连通的分子筛脱水塔、净化气输入管线、净化气输出管线、设置在净化气输入管线和净化气输出管线之间的利用发电燃气机组的烟气余热的余热换热装置,其中,净化气输出管线能与分子筛脱水塔的底端选择性连通,系统包含分子筛脱水塔,其能对天然气中的硫化物、二氧化碳和水等进行吸附,可得到合格的天然气,且该工艺简单,能耗低,天然气的损耗也非常小,另外,该系统还包括余热换热装置,以利用发电后的烟气余热对分子筛脱水塔进行再生,可以节省大量燃料费用,降低生产成本,同时减小能量浪费,保护环境。(The invention provides a natural gas purification system, which comprises a natural gas input pipeline, a natural gas output pipeline, a molecular sieve dehydration tower, a purified gas input pipeline, a purified gas output pipeline and a waste heat exchange device, wherein the molecular sieve dehydration tower is arranged between the natural gas input pipeline and the dehydrated gas output pipeline and can be selectively communicated, the waste heat exchange device is arranged between the purified gas input pipeline and the purified gas output pipeline and utilizes the waste heat of the flue gas of a power generation gas unit, the purified gas output pipeline can be selectively communicated with the bottom end of the molecular sieve dehydration tower, the system comprises the molecular sieve dehydration tower which can adsorb sulfide, carbon dioxide, water and the like in the natural gas to obtain qualified natural gas, the process is simple, the energy consumption is low, the loss of the natural gas is very small, in addition, the system also comprises the waste heat exchange device which utilizes the waste heat of the flue gas after power generation to regenerate the molecular sieve dehydration tower, can save a large amount of fuel expenses, reduce manufacturing cost, reduce energy waste simultaneously, the environmental protection.)

1. A natural gas purification system, comprising:

the natural gas is fed into the pipeline and then fed into the pipeline,

a natural gas output pipeline,

a molecular sieve dehydration tower capable of selective communication arranged between the natural gas input pipeline and the dehydrated gas output pipeline,

the purified gas is fed into the pipeline and then fed into the pipeline,

a purified gas output pipeline,

a waste heat exchange device which is arranged between the purified gas input pipeline and the purified gas output pipeline and utilizes the waste heat of the flue gas of the power generation gas turbine unit,

wherein the purified gas output line is selectively communicable with the bottom end of the molecular sieve dehydration tower.

2. The system of claim 1, wherein a post-regeneration line is disposed in selective communication with the top end of the molecular sieve dehydration tower, the post-regeneration line is connected to the natural gas input line, and a cooler and a water separator are disposed in sequence on the post-regeneration line in a direction from the molecular sieve dehydration tower to the natural gas input line.

3. The system of claim 2, wherein a heat exchanger is disposed in the post-regeneration line between the cooler and the molecular sieve dehydration column in heat exchange relationship with the purified gas input line.

4. The system according to any one of claims 1 to 3, wherein a first temperature controller is provided on the purified gas output line, a heater is provided in parallel on the purified gas output line between the first temperature controller and the molecular sieve dehydration tower, and a first on-off control valve is provided on the purified gas output line in parallel with the heater, the first on-off control valve being connected to the first temperature controller.

5. The system of any of claims 1 to 4, wherein the waste heat exchanger has a heat exchange housing and a heat exchange coil disposed in the heat exchange housing, the heat exchange coil being disposed between the purified gas input line and the purified gas output line, the heat exchange housing having a lower end opening communicating with the flue gas input pipe and an upper end opening for flue gas output.

6. The system of claim 5, wherein an induced draft pipeline is connected in parallel at the upstream end of the flue gas input pipeline, an induced draft fan and a second on-off control valve are arranged on the induced draft pipeline, a second temperature controller is arranged in the inner cavity of the heat exchange shell, and the second temperature controller is connected with the second on-off control valve.

7. The system of any of claims 1 to 6, wherein the purge gas input line is configured to be selectively connectable to the molecular sieve dehydration column.

8. The system of any one of claims 1 to 7, comprising at least two of the molecular sieve dehydration columns in parallel.

9. The system of claim 2, wherein a filtration separator is disposed between the natural gas input line and the molecular sieve dehydration column, and the regenerated line is connected to an upstream end of the filtration separator.

10. The system of any one of claims 1 to 9, wherein a dust filter is provided between the natural gas export line and the molecular sieve dehydration column.

Technical Field

The invention relates to the technical field of natural gas purification and environmental protection, in particular to a natural gas purification system.

Background

The natural gas produced in oil and gas fields mainly comprises hydrocarbon and various impurity gases, the main component of the natural gas is methane, and in addition, hydrogen sulfide, organic sulfur, carbon dioxide and the like exist, and the existence of the acidic substances can not only corrode pipelines and equipment, but also bring serious pollution to the environment. Thus, countries have strict standards for the content of acid gases in commercial natural gas. In recent years, with the proposal of energy conservation and emission reduction concepts, the national requirements on the aspects are stricter and stricter, and the key of reasonably utilizing natural gas resources is to carry out efficient desulfurization and decarburization on the mined natural gas.

The purification method of natural gas in the prior art has the problems of high energy consumption and the like.

Disclosure of Invention

The present invention provides a natural gas purification system, which solves some or all of the above technical problems in the prior art. The system comprises a molecular sieve dehydration tower, can adsorb sulfide, carbon dioxide, water and the like in natural gas, can obtain qualified natural gas, and has the advantages of simple process, low energy consumption and very small loss of the natural gas. In addition, the system also comprises a waste heat exchange device to regenerate the molecular sieve dehydration tower by utilizing the flue gas waste heat after power generation, so that a large amount of fuel cost can be saved, the production cost is reduced, the energy waste is reduced, and the environment is protected.

According to the invention, there is provided a natural gas purification system comprising:

the natural gas is fed into the pipeline and then fed into the pipeline,

a natural gas output pipeline,

a molecular sieve dehydration tower which is arranged between the natural gas input pipeline and the dehydrated gas output pipeline and can be selectively communicated,

the purified gas is fed into the pipeline and then fed into the pipeline,

a purified gas output pipeline,

a waste heat exchange device which is arranged between the purified gas input pipeline and the purified gas output pipeline and utilizes the waste heat of the flue gas of the power generation gas turbine unit,

wherein the purified gas output pipeline can be selectively communicated with the bottom end of the molecular sieve dehydration tower.

In one embodiment, a regenerated pipeline is selectively communicated with the top end of the molecular sieve dehydration tower, the regenerated pipeline is connected with the natural gas input pipeline, and a cooler and a water separator are sequentially arranged on the regenerated pipeline in the direction from the molecular sieve dehydration tower to the natural gas input pipeline.

In one embodiment, a heat exchanger capable of exchanging heat with the purge gas input line is disposed in the post-regeneration line between the cooler and the molecular sieve dehydration column.

In one embodiment, a first temperature controller is disposed on the purified gas output line, a heater is disposed in parallel on the purified gas output line between the first temperature controller and the molecular sieve dehydration tower, and a first on-off control valve is disposed on the purified gas output line in parallel with the heater, the first on-off control valve being connected to the first temperature controller.

In one embodiment, the waste heat exchange device has a heat exchange housing and a heat exchange coil disposed in the heat exchange housing, the heat exchange coil is disposed between the purified gas input pipeline and the purified gas output pipeline, the lower opening of the heat exchange housing is communicated with the flue gas input pipeline, and the upper opening of the heat exchange housing is used for flue gas output.

In one embodiment, an induced draft pipeline is connected in parallel at the upstream end of the flue gas input pipeline, an induced draft fan and a second on-off control valve are arranged on the induced draft pipeline, a second temperature controller is arranged in the inner cavity of the heat exchange shell, and the second temperature controller is connected with the second on-off control valve.

In one embodiment, the purge gas input line is configured to selectively couple to the molecular sieve dehydration column.

In one embodiment, at least two molecular sieve dehydration columns are included in parallel.

In one embodiment, a filtration separator is disposed between the natural gas input line and the molecular sieve dehydration column, and the post-regeneration line is connected to an upstream end of the filtration separator.

In one embodiment, a dust filter is disposed between the natural gas export line and the molecular sieve dehydration tower.

Compared with the prior art, the system has the advantages that the system comprises the molecular sieve dehydration tower, sulfide, carbon dioxide, water and the like in the natural gas can be adsorbed, qualified natural gas can be obtained, the process is simple, the energy consumption is low, and the loss of the natural gas is very small. In addition, the system also comprises a waste heat exchange device to regenerate the molecular sieve dehydration tower by utilizing the flue gas waste heat after power generation, so that a large amount of fuel cost can be saved, the production cost is reduced, the energy waste is reduced, and the environment is protected.

Drawings

Preferred embodiments of the present invention will be described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 shows a schematic diagram of a natural gas purification system according to an embodiment of the invention;

the device comprises a natural gas purification system 100, a natural gas input pipeline 1, a natural gas output pipeline 2, a molecular sieve dehydration tower 3, a purified gas input pipeline 4, a purified gas output pipeline 5, a waste heat exchange device 6, a filtering separator 7, a dust filter 8, a regenerated pipeline 9, a cooler 10, a water separator 11, a heat exchanger 12, a first temperature controller 13, a heater 14, a first switch control valve 15, a heat exchange shell 16, a heat exchange coil 17, a flue gas input pipeline 18, an induced draft pipeline 19, an induced draft fan 20, a second switch control valve 21, a second temperature controller 22 and an electromagnetic valve 23.

In the drawings, like parts are provided with like reference numerals. The figures are not drawn to scale.

Detailed Description

The invention will be further explained with reference to the drawings.

Fig. 1 shows a natural gas purification system 100 according to one embodiment of the invention. As shown in fig. 1, the natural gas purification system 100 includes a natural gas input line 1, a natural gas output line 2, a molecular sieve dehydration tower 3, a purified gas input line 4, a purified gas output line 5, and a waste heat exchange device 6. The natural gas input pipeline 1 is used for being connected with a natural gas source to be purified so as to convey the natural gas to be purified. The natural gas outlet line 2 serves for conveying out the purified natural gas. And the molecular sieve dehydration tower 3 is arranged between the natural gas input pipeline 1 and the natural gas output pipeline 2 and is used for purifying the natural gas. The purge gas input line 4 is intended to be connected to a source of purge gas, for example natural gas that has been purged. The purified gas output pipeline 5 is used for selectively communicating with the bottom end of the molecular sieve dehydration tower and conveying the high-temperature purified gas into the molecular sieve dehydration tower 3 so as to regenerate the molecular sieve. The waste heat exchange device 6 is arranged between the purified gas input pipeline 4 and the purified gas output pipeline 5, and heats the purified gas introduced by the purified gas input pipeline 4 by using the flue gas waste heat of the power generation gas turbine unit.

From this, according to the system 100 of this application, can accomplish the purification effect to the natural gas through the effect of molecular sieve dehydration tower 3, its itself has advantages such as the energy consumption is low, purification efficiency is high, the natural gas loss is little. When the gas turbine set provides power for the whole system, only about 35% of energy is converted into electric energy by the generator set, about 30% of energy is discharged along with exhaust gas, and the exhaust temperature of the exhaust gas is generally more than 500 degrees. For molecular sieves such as 4A, the regeneration temperature is generally around 280 °, and a large amount of heat needs to be absorbed during the regeneration process. This application carries out the regeneration of molecular sieve dehydration tower 3 through setting up the waste heat of 6 make full use of flue gases of waste heat transfer device, has effectively utilized the flue gas waste heat, can save a large amount of fuel expenses, and reduction in production cost reduces the ability extravagant, is favorable to the environmental protection.

In one embodiment, a filtration separator 7 is provided between the natural gas input line 1 and the molecular sieve dehydration column 3. That is, the natural gas passes through the filtering separator 7 before entering the molecular sieve dehydration column 3. Through the arrangement, impurities and small liquid drops carried by natural gas can be removed, the molecular sieve dehydration tower 3 is prevented from being blocked or polluted, and the molecular sieve dehydration tower 3 is protected.

In one embodiment, a dust filter 8 is provided between the natural gas export line 2 and the molecular sieve dehydration column 3. That is, the natural gas passes through the molecular sieve dehydration tower 3 and then enters the dust filter 8 to be filtered by dust, so that the influence of the leaked solid adsorbent on the downstream process is avoided, and the normal operation of the whole system 100 is further ensured.

In one embodiment, post-regeneration line 9 is placed in selective communication at the top of molecular sieve dehydration column 3. The post-regeneration line 9 is connected to the natural gas feed line 1. Further, a cooler 10 and a water separator 11 are provided in this order on the post-regeneration line 9 in the direction from the molecular sieve dehydration tower 3 to the natural gas feed line 1. That is, after entering the molecular sieve dehydration tower 3 to be regenerated, the high-temperature purified gas enters the pipeline 9 after regeneration through the top end of the molecular sieve dehydration tower 3. Then, the gas is cooled by the cooler 10, and then enters the natural gas input pipeline 1 again after being divided by the water divider 11, so that the gas is collected again and purified. The gas subjected to the regeneration treatment is fed to the filtering separator 7 together with the gas in the natural gas source to be purified. This arrangement effectively collects the gas for regeneration, avoiding waste of resources. For example, the cooler 10 may be air-cooled or water-cooled.

Preferably, a heat exchanger 12 is provided on the post-regeneration line 9 between the cooler 10 and the molecular sieve dehydration column 3, the heat exchanger 12 being capable of heat exchange with the purified gas input line 4. That is, after the purified gas enters the purified gas input pipeline 4, the purified gas is firstly subjected to heat exchange in the heat exchanger 12, is primarily heated, and then enters the waste heat exchange device 6 to be further heated. When regeneration operation is carried out, the arrangement can utilize the heat in the gas coming out of the molecular sieve dehydration tower 3 to heat the purified gas, thereby further effectively utilizing energy and avoiding waste.

In one embodiment, a first thermostat 13 is provided on the purge gas output line 5 for monitoring the temperature on the purge gas output line 5 and controlling the opening or closing of the first on-off control valve 15. A heater 14 is arranged in parallel on a purified gas output pipeline 4 between a first temperature controller 13 and the molecular sieve dehydration tower 3, and when the temperature of the purified gas on the purified gas output pipeline 5 does not reach the preset temperature for regenerating the molecular sieve, the heater 14 carries out auxiliary heating. A first on-off control valve 15 is provided on the purge gas output line 5 in parallel with the heater 14. The first on-off control valve 15 is connected to the first thermostat 14. When the load of the residual heat of the flue gas is not enough, the first temperature controller 13 controls the first on-off control valve 15 to close, so that the purifier heated by the residual heat exchange device 6 is further heated by the heater 14, and the temperature required by the dehydration regeneration of the molecular sieve dehydration tower 3 is met. When the temperature of the purified gas on the purified gas output line 5 reaches a predetermined temperature at which the molecular sieve is regenerated, the first on-off control valve 15 is opened, and the purified gas does not pass through the heater 14. For example, the heater 14 may be a water jacket type heating furnace, or a heat exchanger may be provided as the case may be.

In one embodiment, the waste heat exchanging device 6 has a heat exchanging housing 16 and a heat exchanging coil 17 disposed in the heat exchanging housing 16. A heat exchange coil 17 is arranged between the purge gas input line 4 and the purge gas output line 5. The lower end opening of the heat exchange shell 16 is communicated with a flue gas input pipeline 18. And the upper end opening of the heat exchange shell 16 is used for flue gas output. The waste heat exchange device 6 is simple in structure, can well collect waste heat of flue gas and transfer heat into the purified gas input pipeline 4 and the purified gas output pipeline 5. For example, for better collection of the flue gas, the main body of the heat exchange housing 16 is cylindrical, and the upper and lower ends are constructed in a conical shape.

In one embodiment, a draft duct 19 is provided in parallel at the upstream end of the flue gas input duct 18. An induced draft fan 20 for inducing draft and a second on-off control valve 21 for opening or shutting off the induced draft duct 19 are provided on the induced draft duct. A second thermostat 22 is disposed in the inner cavity of the heat exchange housing 16. The second thermostat 22 is connected to a second on-off control valve 21. When the second temperature controller 22 arranged in the heat exchange shell 16 measures that the temperature of the flue gas in the heat exchange shell is too high, the second temperature controller 22 controls the second on-off control valve 21 to be opened, so that the induced draft fan 20 blows air into the heat exchange shell 16. On the contrary, when the temperature of the flue gas measured by the second thermostat 22 disposed in the heat exchange housing 16 is within the preset range, the second thermostat 22 controls the second on-off control valve 21 to close, so that the induced draft fan 20 cannot blow air into the heat exchange housing 16. Through the arrangement, the temperature in the heat exchange shell 16 can be prevented from being overhigh, so that coking and self-carbonization are generated in the heat exchange coil 17, and the service life is prolonged.

In one embodiment, the purge gas input line 5 is configured to be selectively connectable to the molecular sieve dehydration column 3. That is, the purified gas input line 5 can be selectively connected to the waste heat exchanging device 6 and the molecular sieve dehydration tower 3. For example, a solenoid valve 23 may be provided on the corresponding purge gas input line 5 to control the communication and shutoff of the line. When the regeneration operation of the molecular sieve dehydration tower 3 is required, the purified gas input pipeline 5 is communicated with the waste heat exchange device 6, and at the moment, the purified gas input pipeline 5 is cut off from the molecular sieve dehydration tower 3. That is, N10 in solenoid valve 23 is open, while N9 is closed. And when the molecular sieve dehydration tower 3 needs to be cooled, the purified gas input pipeline 5 is communicated with the molecular sieve dehydration tower 3, and at the moment, the purified gas input pipeline 5 is cut off from the waste heat exchange device 6. That is, N10 in solenoid valve 23 is closed and N9 is open.

In one embodiment, system 100 includes at least two molecular sieve dehydration columns 3 in parallel, for example, two or three. By this arrangement, it is possible to improve the working efficiency, for example, one of the molecular sieve dehydration columns 3 is operated for adsorption purification of natural gas, and the other is operated for regeneration and cold blowing in preparation for the adsorption operation. It should be noted that a plurality of electromagnetic valves 23 are disposed at the bottom end and the top end of the molecular sieve dehydration tower 3 for controlling the communication or the cutoff with the corresponding pipelines, so that different molecular sieve dehydration towers 3 are in different working states.

The operation of the system 100 is described below in one embodiment. It should be noted that the discussion herein is in terms of two molecular sieve dehydration columns 3, and the present application, including but not limited to, the number of molecular sieve dehydration columns 3 is two. For example, F1 in the molecular sieve dehydration column 3 located on the left in fig. 1 performs adsorption and purification functions, while F2 in the molecular sieve dehydration column 3 located on the right performs regeneration operations. Specifically, N1 and N5 in the electromagnetic valve 23 are opened, so that the natural gas to be purified is purified and filtered by the natural gas input pipeline 1, the filtering separator 7, N1 in the electromagnetic valve 23, F1 in the molecular sieve dehydration tower 3, N5 in the electromagnetic valve 23 and the dust filter 8 in sequence to reach the standard. At this time, N2 and N6 in the solenoid valve 23 are turned off. Meanwhile, the purified gas passes through N10 in the solenoid valve 23 (at this time, N9 in the solenoid valve 23 is cut off), and then is connected to the natural gas input pipeline 1 through the heat exchanger 12, the waste heat exchange device 6, the heater 14 (passing or not passing according to the different conditions described above), N8 in the solenoid valve 23, F2 in the molecular sieve dehydration tower 3, N4 in the solenoid valve 23, the heat exchanger 12, the cooler 10, and the water separator 11 in sequence. At this time, N3 and N7 in the solenoid valve 23 are closed. After the regeneration of the F2 located in the molecular sieve dehydration column 3, it needs to be cooled. At this time, N10 in the solenoid valve 23 is closed and N9 in the solenoid valve 23 is opened, so that the purified gas is connected to the natural gas input line 1 sequentially through N9 in the solenoid valve 23, N8 in the solenoid valve 23, F2 in the molecular sieve dehydration tower 3, N4 in the solenoid valve 23, the heat exchanger 12, the cooler 10, and the water separator 11.

The operation of regenerating and cooling F1 located in molecular sieve dehydration column 3 and adsorbing and purifying F2 located in molecular sieve dehydration column 3, similar to the above-described process, can be foreseen by those skilled in the art according to the above-described operation, and will not be described herein again. Of course, in the case where three or more molecular sieve dehydration columns 3 are provided, some are subjected to regeneration and cooling, and some are subjected to adsorption and purification, or all are subjected to regeneration and cooling, or all are subjected to adsorption and purification, similarly to the above-described operation, the communication and cut-off of the respective lines can be controlled by the solenoid valves 23.

In addition, a water content analyzer (not shown in the figure) can be arranged at the outlet of the bottom end of the molecular sieve dehydration tower 3 for water content analysis, so that the natural gas dehydration can meet the requirements of the subsequent process. A third temperature controller (not shown) may be provided between the dust filter 8 and the molecular sieve dehydration tower 3, and a third on/off control valve (not shown) may be provided between the water separator 11 and the natural gas input line 1. When the third temperature controller detects that the gas temperature is higher than the preset value, the third switch control valve is controlled to be stopped, so that the inflow of the regenerated gas is cut off, and the high-temperature gas is prevented from flowing to the downstream. A drain port (not shown) may be provided on the filtering separator 7 and the water separator 11, respectively, to be connected to a drain collecting device, thereby discharging the separated water and the like.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily make changes or variations within the technical scope of the present invention disclosed, and such changes or variations should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.