阅读说明：本技术 油气排放深度治理系统 (Oil gas emission depth treatment system ) 是由 郭文泰 徐徜徉 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种油气排放深度治理系统,充分利用浅冷技术对C3+的冷凝回收、膜分离技术对C2+组分的提浓作用和膨胀机无动力深冷对C2的冷凝作用,通过组合技术的应用提高油气中有机物的回收能力。与现有技术相比,膜分离用在深冷不凝气的有机物提浓,此组合方式较用于浅冷不凝气提浓,更能降低排放尾气中有机物含量。采用低温膜分离组件,膜分离器的尾气仍保持低温不凝气原有的部分低温,避免了对膨胀机制冷温度的影响,保障了深冷温度。采用对烃类有机组分低吸附性能的脱水吸附剂作为干燥剂,满足C2组分不会在吸附剂再生环节造成环境排放要求。采用深冷技术根本上解决现有吸附技术存在的C2累积问题,保障了达标排放。(The invention discloses an oil gas emission deep treatment system which fully utilizes the condensation recovery of a shallow cooling technology to C3+, the concentration of a C2+ component by a membrane separation technology and the condensation of an expander unpowered deep cooling to C2, and improves the recovery capacity of organic matters in oil gas by the application of a combination technology. Compared with the prior art, the membrane separation is used for concentrating organic matters in the deep cooling non-condensable gas, and compared with the combination mode for concentrating the shallow cooling non-condensable gas, the combined mode can reduce the content of the organic matters in the discharged tail gas. By adopting the low-temperature membrane separation component, the tail gas of the membrane separator still keeps the original part of the low-temperature non-condensable gas at low temperature, thereby avoiding the influence on the refrigeration temperature of the expander and ensuring the cryogenic temperature. The dehydration adsorbent with low adsorption performance on the hydrocarbon organic components is used as the desiccant, so that the requirement that the C2 component cannot cause environmental emission in the regeneration link of the adsorbent is met. The cryogenic technology is adopted to fundamentally solve the problem of C2 accumulation in the prior adsorption technology, and the discharge up to the standard is ensured.)

1. The oil gas discharge depth treatment system is characterized in that oil gas raw material gas, membrane separation permeation gas and purified gas circulating gas are mixed in a buffer tank, are compressed by a compressor unit and then are sent into a first-stage multi-path heat exchanger through dehydration equipment to be cooled, then enter a shallow ice cooler evaporator to be cooled and then are sent into a low-temperature first-stage separator, the gas phase of the low-temperature first-stage separator is sent into a second-stage multi-path heat exchanger, and then are sent into a low-temperature second-stage separator after being further cooled; the liquid phase of the low-temperature first-stage separator is recycled cold energy through the first-stage multi-path heat exchanger and then enters the normal-temperature separator, the gas phase of the normal-temperature separator returns to the preposed buffer tank, the liquid phase of the normal-temperature separator and the liquid phase of the low-temperature second-stage separator are used as recycled product liquid, and the gas phase outlet of the low-temperature second-stage separator is communicated with the gas inlet of the low-temperature membrane separator set after being moderately heated through the second-stage multi; the permeation gas after membrane separation is used as hydrocarbon enrichment gas, is subjected to heat exchange with the raw material gas before the first-stage multi-path heat exchanger, is heated, is sent to a compressor inlet buffer tank through a vacuum pump for circulation, and is mixed with the raw material gas; the residual gas of the membrane separator is used as driving pressure to be sent to an expansion end of an expansion machine, the expanded low-temperature gas passes through a secondary multi-path heat exchanger and a primary multi-path heat exchanger in sequence, the cold energy is recovered and then is used as brake gas of the expansion machine to be compressed to form purified gas to be discharged, two paths of the purified gas are divided in sequence before being discharged, one path of the purified gas is used as regeneration gas of a dewatering device adsorbent, and the other path of the purified gas returns to an inlet buffer tank of a compressor to be used as flow of a purified gas.

2. The oil and gas emission deep treatment system according to claim 1, wherein the dehydration device is an adsorption regeneration type drying system, and comprises two adsorption tanks filled with dehydration adsorbents, one adsorption tank is used for desorption regeneration of the adsorbents, and the two adsorption tanks work alternately and are controlled by switching of a control valve bank.

3. The oil and gas emission depth treatment system according to claim 1, wherein the compressor outlet air cooling form can be water cooling or air cooling, and the water cooler is usually a shell and tube heat exchanger or the air cooling is usually a tube fin heat exchanger.

4. The oil and gas emission depth treatment system of claim 1, wherein the primary and secondary multi-path heat exchangers are vertical or horizontal wound tube heat exchangers.

5. The oil and gas emission depth treatment system according to claim 1, wherein the secondary multi-path heat exchanger can adopt a dual-path mode, two paths work alternately at regular intervals, and one path is defrosted for standby when the other path works.

6. The oil and gas emission depth treatment system of claim 1, wherein the primary and secondary cryogenic separators are vertical or horizontal gas-liquid separators.

7. The oil and gas emission depth treatment system of claim 1, wherein the membrane separator is roll-to-roll or stacked, the membrane is typically an organic rubbery separation membrane, and the minimum operating temperature is up to-60 ℃.

8. The oil and gas emission depth treatment system of claim 1, wherein the vacuum pump is typically a screw vacuum pump or a liquid ring vacuum pump.

9. The oil and gas emission depth treatment system of claim 2, wherein the adsorbent is a dehydration adsorbent having low adsorption performance for hydrocarbon organic components.

10. The oil and gas emission depth treatment system of claim 9, wherein the adsorbent is a 3A molecular sieve.

Technical Field

The invention relates to the technical field of oil gas recovery, in particular to an oil gas emission deep treatment system.

Background

The traditional compression and condensation process is combined with the novel membrane separation unpowered deep cooling process, and the content of the organic matters in the deeply treated exhaust gas completely meets the national standard (NMOC: 120 mg/m)³Benzene: 4mg/m³) OrLocal standard (NMOC: 60 mg/m)³Benzene: 2mg/m³) Is particularly suitable for the oil gas recovery and treatment of an oil product loading line.

At present, the common treatment technology in the field of oil gas recovery comprises a condensation and adsorption combined technology, an absorption and membrane separation and adsorption combined technology and a condensation and catalytic combustion combined technology.

The former two combined technologies have better effect at the initial stage of operation due to the fact that adsorption is used as a tail-end environment-friendly technology, but the problem of overproof emission can occur after long-time operation, and the problem of environment-friendly emission up to the standard can not be fundamentally solved because the adsorption technology can not solve the problem of C2 accumulation in oil gas. And the condensation technology usually adopts three-level condensation, so that the equipment failure rate is high and the maintenance is complex. The absorption technology has the defects of high operation power consumption and the need of replacing a large amount of absorbent regularly. Although the catalytic combustion technology can solve the problem of emission reaching standards, the safety of the catalytic combustion technology is difficult to guarantee fundamentally, and long-term worry is brought to users. Although expansion refrigeration is applied to oil gas recovery, the expansion refrigeration is mainly used as a refrigeration external circulation process, and the combination of the expansion refrigeration and a membrane separation technology mainly uses membrane separation for concentration of shallow condensed non-condensable gas, and is mainly applied to the field of natural gas light hydrocarbon recovery of oil field well heads. The absorption and membrane separation combined technology can meet the reservoir area environmental protection standard (NMOC: 25 g/m)³) The emission is relatively successfully applied in China, but the emission cannot meet the high requirements of new industrial emission standards, so that a new technology is urgently needed to solve the problem of oil and gas treatment.

Disclosure of Invention

In order to overcome the defects, the invention provides an oil gas emission deep treatment system which fully utilizes the condensation recovery of a shallow cooling technology to C3+, the concentration of a membrane separation technology to C2+ components and the condensation of an expander unpowered deep cooling to C2, and improves the recovery capacity of organic matters in oil gas through the application of a combined technology.

The technical scheme adopted by the invention for realizing the purpose is as follows: the oil gas raw material gas, the membrane separation permeation gas and the purified gas circulating gas are mixed in a buffer tank, are compressed by a compressor unit, are sent into a first-stage multi-path heat exchanger through dehydration equipment to be cooled, then enter a shallow ice-cooling machine evaporator to be cooled, and are sent into a low-temperature first-stage separator, the gas phase of the low-temperature first-stage separator is sent into a second-stage multi-path heat exchanger, and is further cooled and then sent into a low-temperature second-stage separator; the liquid phase of the low-temperature first-stage separator is recovered cold energy through the first-stage multi-path heat exchanger and then enters the normal-temperature separator, the gas phase of the normal-temperature separator returns to the preposed buffer tank, the liquid phase of the normal-temperature separator and the liquid phase of the low-temperature second-stage separator are used as recovered product liquid, and the gas phase outlet of the low-temperature second-stage separator is communicated with the gas inlet of the low-temperature membrane separator group after passing through the second-stage multi; the permeation gas after membrane separation is used as hydrocarbon enrichment gas, is subjected to heat exchange with the raw material gas before the first-stage multi-path heat exchanger, is heated, is sent to a compressor inlet buffer tank through a vacuum pump for circulation, and is mixed with the raw material gas; the residual gas of the membrane separator is used as driving pressure to be sent to an expansion end of an expansion machine, the expanded low-temperature gas passes through a secondary multi-path heat exchanger and a primary multi-path heat exchanger in sequence, the cold energy is recovered and then is used as brake gas of the expansion machine to be compressed to form purified gas to be discharged, two paths of the purified gas are divided in sequence before being discharged, one path of the purified gas is used as regeneration gas of a dewatering device adsorbent, and the other path of the purified gas returns to an inlet buffer tank of the compressor to be used as purified gas. Wherein the adsorbent is a dehydration adsorbent with low adsorption performance to hydrocarbon organic components, such as 3A molecular sieve.

The evaporator of the ice machine with shallow cooling can be a cold source of refrigerant such as Freon or propane and the like and is used as primary shallow cooling equipment; the expander is a device for obtaining low-temperature cold energy by utilizing gas adiabatic expansion, and comprises an expansion end and a braking end, wherein the expander is used as a secondary cryogenic device, and low temperature is obtained by adiabatic expansion of process gas to become a secondary refrigeration cold source.

Furthermore, the dehydration equipment is an adsorption regeneration type drying system, and comprises two adsorption tanks filled with dehydration adsorbents, one adsorption tank is used for desorption regeneration of the adsorbents when the other adsorption tank is used for adsorption, and the two adsorption tanks work alternately and are controlled by switching of a control valve bank.

Further, the cooling form of the compressor discharge air can be water cooling or air cooling, the water cooler is usually a tube type heat exchanger, and the air cooling is usually a tube fin type heat exchanger, but is not limited thereto.

Furthermore, the first-stage multi-path heat exchanger and the second-stage multi-path heat exchanger are vertical or horizontal wound tube type heat exchangers.

Furthermore, the two-stage multi-path heat exchanger can adopt a two-path mode, the two paths work alternately at regular intervals, and one path is defrosted for standby when working.

Further, the first-stage low-temperature separator and the second-stage low-temperature separator are vertical or horizontal gas-liquid separators.

Further, the membrane separator is a roll type or a stacked type, the membrane is an organic rubber state separation membrane, and the minimum working temperature reaches-60 ℃.

Further, the vacuum pump is typically a screw vacuum pump or a liquid ring vacuum pump, but is not limited thereto.

Compared with the prior art, the invention has the beneficial effects that:

the membrane separation is used for concentrating organic matters in the deep cooling non-condensable gas, and compared with the combination mode for concentrating the shallow cooling non-condensable gas, the combined mode can reduce the content of the organic matters in the discharged tail gas.

Secondly, a low-temperature membrane separation component is adopted, the tail gas of the membrane separator still keeps the original part of the low-temperature non-condensable gas at low temperature, the influence on the refrigerating temperature of the expansion machine is avoided, and the cryogenic temperature is guaranteed.

And thirdly, a dehydration adsorbent (such as a 3A molecular sieve) with low adsorption performance on hydrocarbon organic components is used as a drying agent, so that the requirement that the C2 component cannot cause environmental emission in the regeneration link of the adsorbent is met.

Fourthly, the cryogenic technology is adopted to fundamentally solve the problem of C2 accumulation in the prior adsorption technology, and the discharge up to the standard is ensured.

Drawings

Fig. 1 is a system configuration diagram.

Detailed Description

The invention will be further illustrated with reference to specific examples.

As shown in fig. 1, oil gas raw material gas, membrane separation permeate gas and purified gas circulating gas are mixed in a buffer tank 4, are compressed by a compressor 5, are sent into a first-stage multi-path heat exchanger 10 through a dehydration device 6 to be cooled, enter a shallow ice-cooling machine evaporator 13 to be cooled, and are sent into a low-temperature first-stage separator 7, and the gas phase of the low-temperature first-stage separator 7 is sent into a second-stage multi-path heat exchanger 8 and is sent into a low-temperature second-stage separator 9 after being further cooled; the liquid phase of the low-temperature first-stage separator 7 enters a normal-temperature separator 15 after cold energy is recovered by a first-stage multi-path heat exchanger 10, the gas phase of the normal-temperature separator 15 returns to the buffer tank 4, and the liquid phase of the normal-temperature separator 15 and the liquid phase of the low-temperature second separator 9 are used as recovered product liquid. A gas phase outlet of the low-temperature secondary separator 9 is communicated with a gas inlet of the low-temperature membrane separator group 14 after passing through the secondary multi-path heat exchanger 8; the membrane separation permeation gas is used as hydrocarbon enrichment gas, is subjected to heat exchange with the raw material gas before the first-stage multi-path heat exchanger 10 to be heated, is sent to the buffer tank 4 through the vacuum pump 12 to be circulated and mixed with the oil gas raw material gas, the residual gas of the membrane separator is used as driving pressure to be sent to the expander 11, the expanded low-temperature gas passes through the second-stage multi-path heat exchanger 8 and the first-stage multi-path heat exchanger 10 in sequence, is used as brake gas of the expander 11 after cold energy is recovered, is compressed to form purified gas to be discharged, two paths are divided before the purified gas is discharged, one path is sent back to the dehydration equipment 6 to be used as adsorbent regeneration gas, and the. The dehydration device 6 is an adsorption regeneration type drying system, and comprises two adsorption tanks filled with dehydration adsorbents, one adsorption tank is used for adsorption, the other adsorption tank is used for desorption regeneration of the adsorbents, and the two adsorption tanks work alternately and are controlled by a control valve bank.

Example (c): 1000m of oil gas produced by loading certain product oil on a truck³H, after being compressed to 0.8MPa, the raw material gas is dried by a dewatering device, the dew point is-80 ℃, the raw material gas is sent to a first-stage winding multi-channel heat exchanger for cooling, then enters a shallow cooling evaporator for cooling (the temperature can be cooled to-25 ℃), then is sent to a low-temperature first-stage separator, the gas phase of the low-temperature first-stage cooling separator is sent to a second-stage winding multi-channel heat exchanger, and is further cooled and then is sent to a low-temperature second-stage separator (the temperature can be cooled to about-120 ℃); the gas phase of the low-temperature secondary cooling separator is heated by a secondary pipe-winding multi-path heat exchanger, enters a low-temperature membrane separator, the permeation gas is returned to a front buffer tank of a compressor by a vacuum pump, the permeation residual gas enters an expander to be expanded to obtain low temperature below-125 ℃, cold energy is provided for the secondary pipe-winding multi-path heat exchanger and the primary pipe-winding multi-path heat exchanger in sequence, the permeation residual gas enters a braking end of the expander to be compressed to 70Kpa purified gas, one path of the purified gas is used as desorption gas of dehydration equipment, and the other path of the purifiedReturning to the inlet of the compressor to become cycle gas for flow regulation of the expander, discharging the residual purified gas to the ambient atmosphere after passing through a pressure regulating valve, wherein the NMOC:<60mg/m³。

the above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and their concepts should be equivalent or changed within the technical scope of the present invention.