Online Real-time Analysis and Monitoring System for Hydrogen Sulfide in Associated Gas of Oilfield

Abstract

The present invention provides an on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields, which includes a pretreatment device, a desulfurization tower, a combustion furnace and a data acquisition unit. The pretreatment device, the desulfurization tower and the combustion furnace are all connected through pipelines. The data acquisition unit transmits the collected data to a data acquisition terminal through a wireless transmission module. The data acquisition terminal is used for data display and data storage. The data acquisition unit includes a gas flow meter, a first hydrogen sulfide detector, a second hydrogen sulfide detector and a sulfur dioxide detector. The gas flow meter is connected to the input end of the pretreatment device, and the input end of the gas flow meter is connected with an inlet pipeline through a pipeline. The input port of the desulfurization tower is connected with a first vacuum pump and a second vacuum pump, and the output end of the first vacuum pump is connected with an ultraviolet differential absorption spectroscopy gas analyzer. The present invention adopts on-site distributed real-time data acquisition and real-time wirelessly transmits data to the data acquisition terminal for display and storage.

Description

Technical Field

[0001] The present invention relates to the technical field of oil desulfurization, and particularly to an on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields. Background Art

[0002] There are a huge number of oil wells in oil production plants of oil fields. The produced fluid of the oil wells contains associated gas and hydrogen sulfide gas. Before the natural gas is transported and used, it needs to be desulfurized and purified to reduce pipeline corrosion and atmospheric pollutant emissions. Generally, the amount of associated gas in the produced fluid of oil wells is small, and the comprehensive sulfur capacity is small. For the purification treatment process of its associated gas, a dry desulfurization process is mostly adopted.

[0003] Before designing a desulfurization device, it is first necessary to measure the sulfur content and the density of hydrogen sulfide in the natural gas to be desulfurized, so as to determine the total sulfur amount that the desulfurization device needs to process within a desulfurization cycle; then, according to the sulfur capacity of the selected desulfurizer, determine the internal volume and external dimensions of the desulfurization device.

[0004] At present, to measure the hydrogen sulfide content in natural gas, most of the methods are to use a special collection tank or bag to collect gas samples on-site, and then bring them back to the laboratory for monitoring and analysis. This method of collecting gas samples has problems such as inaccurate detection values of hydrogen sulfide gas content caused by delayed storage and delayed detection. At the same time, the gas samples measured only represent the gas concentration at a certain moment during gas sampling, and it is difficult to track and reflect in real time the change of the hydrogen sulfide concentration data of the natural gas being processed by the desulfurization device. The real-time data change of the associated gas is caused by comprehensive factors such as the number of oil wells opened and stopped, resulting in flow changes, pressure fluctuations, and seasonal temperature changes. There is a large deviation between the detected hydrogen sulfide concentration by this method and the actual value. Based on the detection results of this method, calculating the amount of hydrogen sulfide to be processed and the amount of desulfurizer loaded according to the calculated data results have low reliability and cannot meet the actual production needs. Summary of the Invention

[0005] In view of this, the problem to be solved by the present invention is to provide an on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields, which can detect in real time the purification compliance of the desulfurization device, and can also be used for the real-time on-line monitoring of the sulfur dioxide content generated after the combustion of the associated gas heating furnace in oil fields. This has important practical value for the safety management, green development, and rational utilization of associated gas resources in oil fields.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: an on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oilfields, including a pretreatment device, a desulfurization tower, a combustion furnace and a data acquisition unit. The pretreatment device, the desulfurization tower and the combustion furnace are all connected through pipelines. The data acquisition unit transmits the collected data to a data acquisition terminal through a wireless transmission module. The data acquisition terminal is used for data display and data storage. The data acquisition unit includes a gas flowmeter, a first hydrogen sulfide detector, a second hydrogen sulfide detector and a sulfur dioxide detector. The gas flowmeter is connected to the input end of the pretreatment device. The input end of the gas flowmeter is connected to an inlet pipeline through a pipeline. The first hydrogen sulfide detector is connected between the pretreatment device and the desulfurization tower. The second hydrogen sulfide detector is connected between the desulfurization tower and the sulfur dioxide detector. The input port of the desulfurization tower is connected with a first vacuum pump and a second vacuum pump. The output end of the first vacuum pump is connected to an ultraviolet differential absorption spectroscopic gas analyzer. The ultraviolet differential absorption spectroscopic gas analyzer is connected to the input end of the second vacuum pump. The data acquisition unit presets a collection interval time. The data acquisition terminal is configured with a data processor. The data processor reads the difference between the current time value of the system and the collection start time. The data processor is configured with a collection time comparison strategy and a sulfur dioxide prediction strategy. The data processor compares the difference between the current time value of the system and the collection start time with the preset collection interval time according to the collection time comparison strategy. When the difference between the current time value of the system and the collection start time is greater than or equal to the preset collection interval time, the data acquisition unit collects an analog signal and converts the analog signal into a digital signal. The digital signal is transmitted to the data acquisition terminal through the wireless transmission module to obtain the total mass of hydrogen sulfide. The data acquisition terminal uses the sulfur dioxide prediction strategy to obtain the time-average predicted mass of hydrogen sulfide. The current time value of the system is updated to the collection start time value. When the difference between the current time value of the system and the collection start time is less than the preset collection interval time, the data processor compares the difference between the current time value of the system and the collection start time with the preset collection interval time according to the collection time comparison strategy.

[0007] In the present invention, preferably, the input end of the pretreatment device is connected to a chemical replenishment tank through a pipeline. A lift pump is provided between the chemical replenishment tank and the pretreatment device. An inlet valve is provided on the pipeline between the lift pump and the chemical replenishment tank.

[0008] In the present invention, preferably, the pretreatment device includes an absorption tower, an absorption tower agitator and an oxidation blower. The absorption tower agitator is arranged at the bottom of the side wall of the absorption tower. The oxidation blower is connected to the absorption tower through a pipeline.

[0009] In the present invention, preferably, the absorption tower is connected to a gas compression system through a pipeline, and the gas compression system is sequentially provided with a buffer tank, a compressor, and a recovery tank from left to right.

[0010] In the present invention, preferably, the compressor is provided as a plurality of reciprocating piston compressors, and an intercooler is provided between each compressor for cooling the high-temperature gas compressed by the previous compressor.

[0011] In the present invention, preferably, each compressor includes a cylinder and a piston, the piston is fixedly connected to the cylinder, the crankshaft of the compressor is connected to a driving motor through a coupling, the crankshaft is connected to a crank through a shaft pin, the crankshaft and the crank form a connecting rod, the driving motor drives the connecting rod to move, and the connecting rod transmits its acting force to the piston, converting the rotational motion of the crankshaft into the reciprocating motion of the piston.

[0012] In the present invention, preferably, a natural gas outlet is provided at the top of the desulfurization tower, and an outlet valve is provided on the natural gas outlet.

[0013] In the present invention, preferably, the output end of the data acquisition unit is connected with an RS485 interface.

[0014] In the present invention, preferably, the inlet pipeline is provided with a natural gas inlet.

[0015] In the present invention, preferably, an inlet valve is provided on the inlet pipeline.

[0016] The advantages and positive effects of the present invention are as follows: The present invention adopts hydrogen sulfide and sulfur dioxide detection sensors with an electrochemical detection mechanism. The output interface of the hydrogen sulfide concentration signal detected by the hydrogen sulfide sensor is RS485, and the data is transmitted to the data acquisition terminal through a wireless transmission module for processing, display, and storage. At the same time, the natural gas flow rate is detected in real time. The output interface of the natural gas flow rate data is RS485, and the data is transmitted to the data acquisition terminal through a wireless transmission module for processing, display, and storage. The hydrogen sulfide concentration and natural gas flow rate data are processed by computer data processing to obtain the hydrogen sulfide content value, and the total amount of hydrogen sulfide in the pipeline within a certain period of time can also be accumulated. Field distributed real-time data acquisition is adopted to measure the natural gas flow rate, collect the hydrogen sulfide content in natural gas, the tail gas of the heating furnace, and the sulfur dioxide content, and transmit the data wirelessly in real time to the central control room terminal computer for display and storage. At the same time, the data can be transmitted to the oilfield production and gathering station through the Internet. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0018] Figure 1 It is a schematic diagram of signal transmission of the on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to the present invention;

[0019] Figure 2 It is a schematic diagram of the overall structure of the on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to the present invention;

[0020] Figure 3 It is a schematic diagram of the structure of the compressor of the on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to the present invention;

[0021] Figure 4 It is a schematic diagram of data acquisition by the data acquisition unit of the on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to the present invention.

[0022] In the figure: 1, intake pipeline; 2, first vacuum pump; 3, second vacuum pump; 4, ultraviolet differential absorption spectroscopy gas analyzer; 5, chemical replenishment tank; 6, lift pump; 7, feed valve; 8, intermediate cooler; 10, pretreatment device; 11, absorption tower; 12, absorption tower agitator; 13, oxidation blower; 20, desulfurization tower; 21, natural gas outlet; 22, outlet valve; 23, natural gas inlet; 24, inlet valve; 30, combustion furnace; 40, data acquisition unit; 50, wireless transmission module; 60, data acquisition terminal; 61, gas flow meter; 62, first hydrogen sulfide detector; 63, second hydrogen sulfide detector; 64, sulfur dioxide detector; 70, gas compression system; 71, buffer tank; 72, compressor; 721, cylinder; 722, piston; 723, drive motor; 724, crankshaft; 73, recovery tank. Specific embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] As Figures 1 to 4As shown in the figure, the present invention provides an on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields, which includes a pretreatment device 10, a desulfurization tower 20, a combustion furnace 30 and a data acquisition unit 40. The pretreatment device 10, the desulfurization tower 20 and the combustion furnace 30 are all connected through pipelines. The data acquisition unit 40 transmits the collected data to a data acquisition terminal 60 through a wireless transmission module 50. The data acquisition terminal 60 is used for data display and data storage. The data acquisition unit 40 includes a gas flow meter 61, a first hydrogen sulfide detector 62, a second hydrogen sulfide detector 63 and a sulfur dioxide detector 64. The gas flow meter 61 is connected to the input end of the pretreatment device 10. The input end of the gas flow meter 61 is connected to an inlet pipeline 1 through a pipeline. The first hydrogen sulfide detector 62 is connected between the pretreatment device 10 and the desulfurization tower 20. The second hydrogen sulfide detector 63 is connected between the desulfurization tower 20 and the sulfur dioxide detector 64. The input port of the desulfurization tower 20 is connected with a first vacuum pump 2 and a second vacuum pump 3. The output end of the first vacuum pump 2 is connected to an ultraviolet differential absorption spectroscopy gas analyzer 4. The ultraviolet differential absorption spectroscopy gas analyzer 4 is connected to the input end of the second vacuum pump 3. The data acquisition unit 40 presets a collection interval time. The data acquisition terminal 60 is configured with a data processor. The data processor reads the difference between the current time value of the system and the start time of collection. The data processor is configured with a collection time comparison strategy and a sulfur dioxide prediction strategy. The data processor compares the difference between the current time value of the system and the start time of collection with the preset collection interval time according to the collection time comparison strategy. When the difference between the current time value of the system and the start time of collection is greater than or equal to the preset collection interval time, the data acquisition unit 40 collects an analog signal and converts the analog signal into a digital signal. The digital signal is transmitted to the data acquisition terminal 60 through the wireless transmission module 50 to obtain the total mass of hydrogen sulfide. The data acquisition terminal 60 uses the sulfur dioxide prediction strategy to obtain the time-averaged predicted mass of hydrogen sulfide. The current time value of the system is updated to the start time value of collection. When the difference between the current time value of the system and the start time of collection is less than the preset collection interval time, the data processor compares the difference between the current time value of the system and the start time of collection with the preset collection interval time according to the collection time comparison strategy.The data acquisition unit 40 transmits the acquired data to the data acquisition terminal 60 through the wireless transmission module 50. The data acquisition terminal 60 realizes the remote control of the system and the issuance of instructions. The data acquisition unit 40 includes a gas flowmeter 61, a first hydrogen sulfide detector 62, a second hydrogen sulfide detector 63, and a sulfur dioxide detector 64. The gas flowmeter 61 measures the gas flow value of the natural gas containing hydrogen sulfide. The first hydrogen sulfide detector 62 is used to detect that the input port of the pretreatment desulfurization tower 20 is connected with a first vacuum pump 2 and a second vacuum pump 3. The output end of the first vacuum pump 2 is connected with an ultraviolet differential absorption spectroscopic gas analyzer 4. The ultraviolet differential absorption spectroscopic gas analyzer 4 and the input end of the second vacuum pump 3 are connected. The first vacuum pump 2 can pump out the desulfurized natural gas, and the hydrogen sulfide content is measured by the ultraviolet differential absorption spectroscopic gas analyzer 4. Then, the detected natural gas is pumped back into the desulfurization tower 20 through the second vacuum pump 3 to judge whether the measured hydrogen sulfide content meets the condition within the standard value range. The standard value range is a standard preset range value. There is no need to collect gas samples on-site with a collection tank or bag and then take them back to the laboratory for monitoring and analysis. Real-time online collection solves the problem of inaccurate detection values of hydrogen sulfide gas content caused by delayed storage and delayed detection. The second hydrogen sulfide detector is used to detect the hydrogen sulfide content of the hydrogen sulfide gas removed again. The collected hydrogen sulfide content data is uploaded to the data acquisition terminal 60 through the wireless transmission module 50 in time, which is convenient for data processing and data prediction. It can detect the purification compliance of the desulfurization device in real time and predict the annual scientific dosage of the desulfurizer, so as to guide and ensure the effective operation of the desulfurization equipment.

[0027] In this embodiment, further, the input end of the pretreatment device 10 is communicated with a chemical replenishment tank 5 through a pipeline. A lift pump 6 is provided between the chemical replenishment tank 5 and the pretreatment device 10. A feed valve 7 is provided on the pipeline between the lift pump 6 and the chemical replenishment tank 5. The feed valve 7 can be an artificial valve or an electric valve. Natural gas enters the pretreatment device 10 through the inlet pipeline 1. The desulfurizer is put into the chemical replenishment tank 5, and the feed valve 7 is opened. The desulfurizer in the chemical replenishment tank 5 is pumped into the pretreatment device 10 by the lift pump 6 to carry out the natural gas pretreatment process first.

[0028] In this embodiment, further, the pretreatment device 10 includes an absorption tower 11, an absorption tower 11 agitator, and an oxidation blower 13. The absorption tower 11 agitator is arranged at the bottom of the side wall of the absorption tower 11. The oxidation blower 13 is communicated with the absorption tower 11 through a pipeline.

[0029] In this embodiment, further, the absorption tower 11 is connected to a gas compression system 70 through a pipeline. The gas compression system 70 is sequentially provided with a buffer tank 71, a compressor 72, and a recovery tank 73 from left to right. Natural gas enters from the bottom of the absorption tower 11 and contacts countercurrently with the lean triethylene glycol solution entering from the top in the tower. The dehydrated natural gas leaves from the top of the absorption tower 11, and the rich triethylene glycol solution is discharged from the bottom of the tower and passes through the gas compression system 70. The condenser provided in the gas compression system 70 condenses the natural gas. The hydrocarbon gas dissolved therein is flashed out to the maximum extent through a flash tank. The liquid phase leaving the flash tank flows into the buffer tank 71 after being filtered by a filter, enters the desulfurization tower 20 after being heated by a multi-stage compressor 72, and the condensed water flows back to the recovery tank 73.

[0030] In this embodiment, further, the compressor 72 is provided as a plurality of reciprocating piston compressors 72, and an intercooler 8 is provided between each compressor 72. The intercooler 8 is used to cool the high-temperature gas compressed by the previous compressor 72.

[0031] In this embodiment, further, each compressor 72 includes a cylinder 721 and a piston 722. The piston 722 is fixedly connected to the cylinder 721. The crankshaft 724 of the compressor 72 is connected to a drive motor 723 through a coupling. The crankshaft 724 is connected to a crank through a shaft pin. The crankshaft 724 and the crank form a connecting rod. The drive motor 723 drives the connecting rod to move. The connecting rod transmits its acting force to the piston 722, and the rotational motion of the crankshaft 724 is converted into the reciprocating motion of the piston 722. The process of compressing gas is divided into four parts: expansion, suction, compression, and discharge. According to the required pressure, the compressor 72 is divided into several stages to increase the pressure step by step, and an intercooler 8 is provided after each stage of the compressor 72. The intercooler 8 is used to cool the high-temperature gas compressed in each stage until it is discharged after reaching the rated pressure.

[0032] In this embodiment, further, the top of the desulfurization tower 20 is provided with a natural gas outlet 21, and an outlet valve 22 is provided on the natural gas outlet 21. The outlet valve 22 can be an artificial valve or an electric valve. The natural gas outlet 21 is used as the outlet of natural gas to release clean and up-to-standard natural gas.

[0033] In this embodiment, further, the output end of the data acquisition unit 40 is connected to an RS485 interface. The output interface of the data acquisition unit 40 is RS485, and the data is transmitted to the data acquisition terminal 60 through the wireless transmission module 50 for processing, display, and storage.

[0034] In this embodiment, further, the intake pipeline 1 is provided with a natural gas inlet 23, and the natural gas inlet 23 serves as an inlet for natural gas to introduce a natural gas mixture containing hydrogen sulfide.

[0035] In this embodiment, further, an intake valve 24 is provided on the intake pipeline 1. The intake valve 24 can be an artificial valve or an electric valve. By opening and closing the intake valve 24, the flow rate of the natural gas mixture introduced can be controlled.

[0036] The working principle and process of the present invention are as follows: During use, natural gas enters the pretreatment device 10 through the intake pipeline 1. The desulfurization agent is placed in the reagent supply tank 5, and the feed valve 7 is opened. The desulfurization agent in the reagent supply tank 5 is pumped into the pretreatment device 10 by the lift pump 6 to conduct the natural gas pretreatment process first. The data acquisition unit 40 transmits the collected data to the data acquisition terminal 60 through the wireless transmission module 50. The data acquisition terminal 60 realizes remote control of the system and issuance of instructions. The data acquisition unit 40 includes a gas flow meter 61, a first hydrogen sulfide detector 62, a second hydrogen sulfide detector 63, and a sulfur dioxide detector 64. The gas flow rate value of the natural gas containing hydrogen sulfide is measured by the gas flow meter 61. The first hydrogen sulfide detector 62 is used to detect that the input port of the pretreatment desulfurization tower 20 is connected with a first vacuum pump 2 and a second vacuum pump 3. The output end of the first vacuum pump 2 is connected with an ultraviolet differential absorption spectroscopy gas analyzer 4, and the input end of the ultraviolet differential absorption spectroscopy gas analyzer 4 is connected with the second vacuum pump 3. The first vacuum pump 2 can pump out the desulfurized natural gas, and the hydrogen sulfide content is measured by the ultraviolet differential absorption spectroscopy gas analyzer 4. Then, the detected natural gas is pumped back into the desulfurization tower 20 through the second vacuum pump 3 to determine whether the measured hydrogen sulfide content meets the condition within the standard numerical range. The standard numerical range is a standard preset range value. There is no need to collect gas samples on-site with a collection tank or bag and then bring them back to the laboratory for monitoring and analysis. Real-time online collection solves the problem of inaccurate detection values of hydrogen sulfide gas content caused by delayed storage and delayed detection. The second hydrogen sulfide detector is used to detect the hydrogen sulfide content of the removed hydrogen sulfide gas again. The collected hydrogen sulfide content data is uploaded to the data acquisition terminal 60 through the wireless transmission module 50 in a timely manner, which is convenient for data processing and data prediction. The purification compliance of the desulfurization device can be detected in real time, and the annual scientific dosage of the desulfurization agent can be predicted, so as to guide and ensure the effective operation of the desulfurization equipment. In this embodiment, the data collected in real time by the data acquisition unit includes the gas flow rate V of the natural gas in the incoming line measured by the gas flow meter ijk (unit m 3( / s). The first hydrogen sulfide detector is used to measure the concentration value of hydrogen sulfide in the mixed natural gas after being pretreated by the pretreatment device, and the second hydrogen sulfide detector is used to measure the concentration value of hydrogen sulfide in the natural gas after desulfurization by the desulfurization tower. The difference between the two values gives the hydrogen sulfide concentration ρ ijk (unit: g / m 3 ). Therefore, the total mass m ijk (unit: kg) of hydrogen sulfide flowing through in the one hour before and one hour after (a total of two hours) the k-th detection on the j-th day of the i-th month is:

[0037] m ijk =V ijk ×ρ ijk ×7200÷1000 = 7.2V ijk ρ ijk

[0038] The total mass m ij (unit: kg) of hydrogen sulfide flowing through on the j-th day of the i-th month is:

[0039]

[0040] The mass of hydrogen sulfide flowing through per hour on average on the j-th day of the i-th month (unit: kg) is:

[0041]

[0042] If the i-th month has 31 days, then the total mass m i (unit: kg) of hydrogen sulfide flowing through in the i-th month is:

[0043]

[0044] The mass of hydrogen sulfide flowing through per hour on average in the i-th month (unit: kg) is:

[0045]

[0046] The mass of hydrogen sulfide flowing through per day on average in the i-th month is m i / 31.

[0047] The total mass m (unit: kg) of hydrogen sulfide flowing through throughout the year is:

[0048] If there are 365 days in that year, then the mass of hydrogen sulfide flowing through per hour on average is:

[0049] Therefore, the daily average mass of hydrogen sulfide calculated is m / 365.

[0050] Among them, the pretreatment device 10 mainly completes the dehydration process of natural gas. This is because natural gas usually contains water vapor, and acidic gases will corrode pipelines and equipment. Water vapor is likely to form hydrates when the pressure and temperature of natural gas change, which does not meet the requirements of natural gas gathering and transportation. Therefore, the water vapor in natural gas is removed through the pretreatment process. The pretreatment device 10 includes an absorption tower 11, an absorption tower 11 agitator, and an oxidation blower 13. The absorption tower 11 agitator is arranged at the bottom of the side wall of the absorption tower 11, and the oxidation blower 13 is connected to the absorption tower 11 through a pipeline. The specific process is that natural gas enters from the bottom of the absorption tower 11, and the dehydrated natural gas leaves from the top of the absorption tower 11. After passing through the gas compression system 70, the condenser provided in the gas compression system 70 condenses the natural gas. The dissolved hydrocarbon gas is flashed out to the maximum extent via a flash tank. The liquid phase leaving the flash tank flows into a buffer tank 71 after being filtered by a filter, and enters a desulfurization tower 20 after being heated by a multi-stage compressor 72. The condensed water flows back to a recovery tank 73.

[0051] The present invention is designed by using Internet of Things sensors and intelligent instrumentation technologies. It adopts on-site distributed real-time data acquisition to measure the natural gas flow rate, collect the hydrogen sulfide content in natural gas, the tail gas of the heating furnace and the sulfur dioxide content, and wirelessly transmit the data to the central control room terminal computer for display and storage in real time. At the same time, the data can be transmitted to the oilfield production and gathering station via the Internet. By measuring the natural gas flow rate online in real time within a certain period, detecting the dynamic concentration of hydrogen sulfide, the dosage of desulfurization agent filled in the desulfurization device within an annual cycle can be predicted, guiding the optimization of the desulfurization device design, avoiding problems such as insufficient filling of desulfurization agent and excessive addition, achieving reasonable design of the desulfurization device, economical investment, high operation efficiency, and precise utilization of desulfurization agent. Second, it can detect in real time whether the desulfurization and purification of natural gas meet the standards and the desulfurization effect of the desulfurization device. Third, by measuring the natural gas flow rate online in real time and detecting the dynamic concentration of hydrogen sulfide, the effective consumption amount and the current remaining amount of the desulfurization agent within a time period can be calculated, determining the remaining usable time, so as to guide the timely update of the desulfurization agent and avoid the troubles caused by the exhaustion or failure of the desulfurization agent. Fourth, it detects the sulfur dioxide content in the tail gas of the associated gas heating furnace, provides monitoring data for the technical transformation of the heating furnace, realizes the up-to-standard emission of the tail gas, green production of the oilfield, and improves the image of the oilfield enterprise. The present invention effectively solves the problem of inaccurate monitoring results of the hydrogen sulfide content in natural gas at present. At the same time, it has the function of on-site real-time detection, has the advantage of providing accurate monitoring data in a timely manner, can scientifically measure the hydrogen sulfide gas content in natural gas and the flow rate of natural gas; predict the scientific dosage of desulfurization agent and optimize the design of the desulfurization device; can detect in real time whether the desulfurization device is purified up to the standard; and prompt the time for replacing the agent to ensure the effective operation of the desulfurization facilities, becoming a necessary on-site technical equipment and effective means.

[0052] The above has described the embodiments of the present invention in detail, but the above content is only the preferred embodiments of the present invention and cannot be considered as defining the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope covered by this patent.

Claims

1. An on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oilfield, characterized in that, it includes a pretreatment device (10), a desulfurization tower (20), a combustion furnace (30) and a data acquisition unit (40). The pretreatment device (10), the desulfurization tower (20) and the combustion furnace (30) are all connected through pipelines. The data acquisition unit (40) transmits the collected data to a data acquisition terminal (60) through a wireless transmission module (50). The data acquisition terminal (60) is used for data display and data storage. The data acquisition unit (40) includes a gas flowmeter (61), a first hydrogen sulfide detector (62), a second hydrogen sulfide detector (63) and a sulfur dioxide detector (64). The gas flowmeter (61) is connected to the input end of the pretreatment device (10). The input end of the gas flowmeter (61) is connected to an inlet pipeline (1) through a pipeline. The first hydrogen sulfide detector (62) is connected between the pretreatment device (10) and the desulfurization tower (20). The second hydrogen sulfide detector (63) is connected between the desulfurization tower (20) and the sulfur dioxide detector (64). The input port of the desulfurization tower (20) is connected with a first vacuum pump (2) and a second vacuum pump (3). The output end of the first vacuum pump (2) is connected to an ultraviolet differential absorption spectroscopic gas analyzer (4). The ultraviolet differential absorption spectroscopic gas analyzer (4) is connected to the input end of the second vacuum pump (3); the data acquisition unit (40) presets a collection interval time. The data acquisition terminal (60) is configured with a data processor. The data processor reads the difference between the current time value of the system and the start time of collection. The data processor is configured with a collection time comparison strategy and a sulfur dioxide prediction strategy. The data processor compares the difference between the current time value of the system and the start time of collection with the preset collection interval time according to the collection time comparison strategy; when the difference between the current time value of the system and the start time of collection is greater than or equal to the preset collection interval time, the data acquisition unit (40) collects an analog signal and converts the analog signal into a digital signal. The digital signal is transmitted to the data acquisition terminal (60) through the wireless transmission module (50) to obtain the total mass of hydrogen sulfide. The data acquisition terminal (60) obtains the time-average predicted mass of hydrogen sulfide by using the sulfur dioxide prediction strategy. The current time value of the system is updated to the start time value of collection; when the difference between the current time value of the system and the start time of collection is less than the preset collection interval time, the data processor compares the difference between the current time value of the system and the start time of collection with the preset collection interval time according to the collection time comparison strategy.

2. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oilfield according to claim 1, characterized in that, The input end of the pretreatment device (10) is connected to a chemical replenishment tank (5) through a pipeline. A lift pump (6) is provided between the chemical replenishment tank (5) and the pretreatment device (10). A feed valve (7) is provided on the pipeline between the lift pump (6) and the chemical replenishment tank (5).

3. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 1, characterized in that, the pretreatment device (10) includes an absorption tower (11), an absorption tower (11) agitator and an oxidation blower (13). The absorption tower (11) agitator is arranged at the bottom of the side wall of the absorption tower (11). The oxidation blower (13) is connected to the absorption tower (11) through a pipeline.

4. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 3, characterized in that, the absorption tower (11) is connected to a gas compression system (70) through a pipeline. The gas compression system (70) is sequentially provided with a buffer tank (71), a compressor (72) and a recovery tank (73) from left to right.

5. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 4, characterized in that, the compressor (72) is provided as a plurality of reciprocating piston compressors (72). An intercooler (8) is provided between each compressor (72). The intercooler (8) is used to cool the high-temperature gas compressed by the previous compressor (72).

6. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 4, characterized in that, each compressor (72) includes a cylinder (721) and a piston (722). The piston (722) is fixedly connected to the cylinder (721). The crankshaft (724) of the compressor (72) is connected to a drive motor (723) through a coupling. The crankshaft (724) is connected to a crank through a shaft pin. The crankshaft (724) and the crank form a connecting rod. The drive motor (723) drives the connecting rod to move. The connecting rod transmits its acting force to the piston (722), and the rotational movement of the crankshaft (724) is converted into the reciprocating movement of the piston (722).

7. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 1, characterized in that, the top of the desulfurization tower (20) is provided with a natural gas outlet (21). An outlet valve (22) is provided on the natural gas outlet (21).

8. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 1, characterized in that, the output end of the data acquisition unit (40) is connected with an RS485 interface.

9. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 1, characterized in that, the inlet pipeline (1) is provided with a natural gas inlet (23).

10. The on-line real-time analysis and monitoring system for hydrogen sulfide in associated gas of oil fields according to claim 1, characterized in that, the inlet pipeline (1) is provided with an inlet valve (24).

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