CN2089477U

CN2089477U - Separating device for petroleum gas liquefication

Info

Publication number: CN2089477U
Application number: CN 91207834
Authority: CN
Inventors: 石行
Original assignee: Beijing Xicheng District Newly Opened General Test Plant
Current assignee: Beijing Xicheng District Newly Opened General Test Plant
Priority date: 1991-05-21
Filing date: 1991-05-21
Publication date: 1991-11-27

Abstract

The utility model relates to a separating device for petroleum gas liquefaction, belonging to oilfield and the processing unit of the gas processing plant, which is composed of an air heat exchanger, a turbo compressor, a light hydrocarbon separator, a liquefied natural gas separator. The utility model is characterized in that the utility model is provided with a compressor, a birotor aircraft turbofan engine which is incorporated with the prime motor, a power turbine, a power turbine, a deep cooling expansion turbine, an intermediate pressure compressor, a generator, a gas vessel and a heat transfer cold box which are driven by the birotor aircraft turbofan engine. The utility model liquidizes the processed gas by the two-stage refrigeration of the by-pass air of the aerial engine and the compressed medium pressure air of the intermediate pressure compressor. The utility model can be directly modified from an aerial engine in order to decrease the cost of designing and manufacture.

Description

Separating device for petroleum gas liquefication

A kind of separating unit for liquefying petroleum gas, it belongs to the processing unit (plant) of oil and gas conditioning, is applicable to the processing factory of petroleum gas (accompanying gas when comprising oil production and Sweet natural gas etc.).

Are method separation light hydrocarbon component (the above heavy constituent of butane) and other the inflammable gass wherein that adopt compression and swell refrigeration to various petroleum gas majorities now.Various components after the separation not only can be done different purposes, and because liquefaction back volume dwindles greatly, help transportation and storage.For the such multicomponent gas of petroleum gas, now isolating methods of liquefaction that adopt are carried out the separation of component more.Use the different characteristic of liquefying-point temperature of different components, coldly to the liquefaction temperature of a certain component, and the low component of liquefaction temperature still keeps gaseous state, uses gravity separator to carry out the gravity gas-liquid separation then petroleum gas.This separation method simple in structure, the separation efficiency height.Since in the petroleum gas liquefying-point of each component under normal pressure all below normal temperature, in order to make its liquefaction, the method that is now adopted all is to use compressor that it is directly pressurizeed, use cooling heat exchanger that it is cooled to be lower than normal temperature then, institute's plus-pressure makes the high-temperature component in the petroleum gas be issued to liquefying-point at the low temperature of rate of exchange economy.For stage trapping (polycomponent separation) to repeatedly compress.Because the flow when petroleum gas is handled is very big, the compressor majority that adopts is a Systems of Centrifugal Compressor Unit now.And the design of large centrifugal compressor unit and manufacturing are all very difficult.Particularly since petroleum gas processing plant the batch of compressor is required is not very big, handled petroleum gas component of each gas processing factory and character and working parameter (as flow etc.) are all inequality, so the design variable of its compressor is also inequality.If use identical compressor, then most compressors all are not operated on the design point point, and this is very big to compressor efficiency, working life influence.If each compressor all by future the work point the petroleum gas parameter manufacture and design, this can increase very big design and manufacture cost, and the design and construction cycle of the gas processing factory that extended greatly.In fact also before being difficult in the device operation point-device, constant operating parameter is proposed.Because compressor is a specialized designs manufacturing, this has caused very big difficulty for the maintenance of equipment, and what difficult assurance was produced normally carries out.Because petroleum gas is along with oil and the passage of Natural gas extraction time, its character also can change, so both be the compressor that specialized designs is made, its working point also will change, can not in whole life cycle, all remain on best operating point, and in the most of the time, all to reduce operational efficiency.

The compressor of high-power now, big flow, the most advanced with aero-turbine, its efficient, work-ing life and power weight ratio have all reached very high level.But, because what pneumatic plant compressed in the aero-turbine is air dielectric, the fluid properties difference of air dielectric and petroleum gas is bigger, when the pneumatic plant of use aero-turbine directly compresses petroleum gas as the petroleum gas compressor, need it is carried out great Transform Type design, turbine blade and casing all need redesign to calculate.Therefore the workload of retrofiting is also very big, particularly can not utilize retired aero-turbine that also has certain residual life and the stand-by engine of eliminating, and this is a very big waste.

The purpose of this utility model is that invention one cover petroleum gas separates liquefying plant, its use existing separate liquefaction different flow process, make the influence of petroleum gas change of properties little, can use the design of existing aero-turbine or directly utilize existing aero-turbine, reduce this Design of device manufacturing cost.Very strong adaptability is arranged.

Structure of the present utility model is formed as shown in Figure 1.It has air heat exchanger 1 and 2, turbocompressor 3 and 4, light hydrocarbon separator 5 and liquefied natural gas separator 6, it is characterized in that: hpc 7 is arranged, combustion chamber 8, high-pressure turbine 9, low-pressure turbine 10, turbocompressor 3 and hpc 7, combustion chamber 8, high-pressure turbine 9 and low-pressure turbine 10 have been formed a dual-rotor aviation turbofan engine 11, turbocompressor 3 is the low-pressure compressor of aerial turbo fan engine 11, the outer culvert air-flow that this low-pressure turbine pneumatic plant 2 is compressed is the low pressure cooling air, outside in the low pressure cooling air flow process of Haning, air water separator 12 and 13 are arranged, air water separator 12 and 13 input aperture ends are connected on the delivery port end of air heat exchanger 1 and 2 respectively, after air water separator 12, be connected to the turbo-driven compressor 14 that drives by shallow cold expansion turbine 15, behind shallow cold expansion turbine 15, precooling ice chest 16 is arranged, the nozzle place of dual-rotor aviation turbofan engine 11 is connected to work turbine 17, work turbine 17 links to each other with turbocompressor 4, and be connected to deep cooling expansion turbine 19 and generator 20, behind turbocompressor 4 air-outs, be connected to air heat exchanger 21, connect precooling ice chest 16 gas input port that is cooled afterwards, precooling ice chest 16 gas delivery port that is cooled is connected to the air-in of deep cooling expansion turbine 9, behind its delivery port, be serially connected with deep cooling ice chest 22, in cold case 23, and by in cold case refrigerant delivery port take back turbocompressor 4 inlet mouth places, 4 inlet mouth places also are connected to the air container 18 that can store certain air at turbocompressor, 19 groups of turbocompressor 4 and deep cooling expansion turbines are for having removed the aerial turbo fan engine of low-pressure compressor and combustion chamber and fuel oil control accessory case, the cold case 23 gas inlet end that is cooled during processed petroleum gas input aperture directly is connected to, its exit end is connected to light hydrocarbon separator 5 input apertures, light hydrocarbon separator 5 gas output ends are connected to the gas inlet end that is cooled of deep cooling ice chest 22, and exit end is connected to the input terminus of natural gas liquids separator 6.

Accompanying drawing 1 also is a schematic flow sheet of the present utility model, sees from figure, and it is made up of three gas flow processs.They are: low pressure cooling air flow process; Middle compacting freezing air flow process and constant voltage petroleum gas liquefaction separation process.Wherein, low pressure cooling air flow process is open cycle, and middle compacting freezing air flow process is a closed cycle.These two circulations all use air as refrigerant, and reach the normal pressure liquefaction temperature of flammable Sweet natural gas in the petroleum gas (mainly being methane) by two-stage refrigerating method.In low pressure cooling air flow process, outside air is sucked and compression by the low-pressure turbine pneumatic plant 3 of aerial turbo fan engine group 11.Low-pressure air after pneumatic plant 3 is pressed is divided into two parts (corresponding to the intension air-flow and the outer culvert air-flow of former engine).The outer air-flow of containing is drawn, and uses as the refrigerant in this refrigerant gas flow process.And the intension air-flow, is sent into combustion chamber 8 and is added fuel combustions after hpc 7 further compresses as the air source of aero-turbine group, and the power of whole device is provided.High temperature and high pressure gas after the burning is by high-pressure turbine 9 and the acting of low-pressure turbine 10 puffings, the energy that high and low pressure turbine 9,10 absorbs drives 7,3 work of high and low pressure turbocompressor again, constitutes the pneumatic plant of independent operating and the gas-engine pumping plant of primover one voluntarily.Because former nozzle of aircraft engine tail place exhaust body also has a large amount of kinetic energy and interior energy, therefore install a free power turbine 17 additional.Work turbine fully absorbs kinetic energy and the interior energy in the tail exhaust, and the propulsion source in the compacting freezing air flow process in the conduct, presses turbocompressor 4 in the drive.With work turbine 17 and middle pressure turbocompressor 4 coaxial also have deep cooling expansion worm gear 19 and generator 20.Part kinetic energy when suppressing the freezing air swell refrigeration during deep cooling expansion worm gear 19 is used for reclaiming.Because work turbine 17 and deep cooling expansion turbine 19 output ratings greater than middle pressure turbocompressor 4 needed power inputs, also for the ease of adjusting cooling air flow process operating mode, have installed generator 20 additional simultaneously, are used to absorb unnecessary energy.The power of whole petroleum gas treatment unit is provided by an aerial turbo fan engine 11, does not need extraneous intake, and the combustion gas heat energy output with certain heat that certain electric energy is arranged and discharged by work turbine 17.

Details are as follows for gas flow process of the present utility model:

Low pressure cooling air flow process.Outside air is contained air-flow outward and is drawn after 3 compressions of low-pressure turbine pneumatic plant.Because air compression back temperature will raise, and therefore be compressed air by 1 pair of air heat exchanger and lower the temperature, and make it temperature and roll back room temperature.After the cooling, being compressed airborne portion of water will condense, and therefore allows it pass through air water separator 12, removes the moisture that condenses into liquid.Gas under pressure after the cooling further pressurizes by the turbo-driven compressor 14 that is driven by shallow cold expansion turbine 15, strengthens the pressure that is compressed gas, to improve the refrigeration temperature difference.Because further after the pressurization, the temperature that is compressed air will raise once more,, and remove redundant moisture with air water separator 13 once more therefore by air heat exchanger 2 coolings.By shallow cold expansion turbine 15 adiabatic expansions of the normal temperature high voltage air admission after twice pressurization.Because gas is after adiabatic expansion, temperature descends, and the air that is compressed after therefore expanding becomes the atmospheric low-temperature air, and the high-pressure air that is used in precooling ice chest 16 centerings compacting freezing air flow process cools off, and takes away the heat of high-pressure air.The kinetic energy that shallow cold expansion turbine 15 is had when absorbing forced air adiabatic expansion in the low pressure cooling air flow processs is to drive turbo-driven compressor 14.Absorbed the heat of the high-pressure air in the middle compacting freezing air flow process by precooling ice chest 16, the low-pressure air temperature recovery enters atmosphere near room temperature as waste gas, finishes the circulation of low pressure cooling air flow process.Therefore, this flow process is an open cycle.

Middle compacting freezing air flow process.Cooling air medium in this flow process recycles.During entering, the round-robin high-pressure air presses pressurization compression in the turbocompressor 4.Because turbocompressor 4 has bigger compression ratio, the air after the pressurization has bigger pressure, and simultaneous temperature also rises higher, therefore carries out cooling heat transferring by air heat exchanger 21.Temperature drops near normal temperature, and then enters precooling ice chest 16 and cool off, and the heat that is had is further given low pressure cooling air medium, thereby reduce the hot-side temperature of this refrigerating machine.The air dielectric of cryogenic high pressure enters deep cooling expansion turbine 19 adiabatic expansions, and pressure is reduced to the pressure before turbocompressor 4 compressions, and temperature is reduced to and can makes the temperature that methane liquefies in the petroleum gas under normal pressure.Utmost point Cryogenic air medium after the expansion enters deep cooling ice chest 22, to isolating in the petroleum gas behind the lighter hydrocarbons residual gas liquefaction of lowering the temperature.Also remain under the normal pressure under the lighter hydrocarbons liquefaction temperature by the cooling air medium temperature after the deep cooling ice chest heat absorption, therefore, cold case 23 carries out heat exchange with petroleum gas in entering, and reduces the petroleum gas temperature, makes lighter hydrocarbons combination liquefaction in the petroleum gas.In finish heat exchange in the cold case 23 air dielectric press turbocompressor 4 to circulate in reentering.

The petroleum gas treatment scheme.Cold case 23 in being entered by the purification petroleum gas of collecting and transfer line is sent here, by middle compacting freezing air institute cooling heat transferring, temperature drops under the lighter hydrocarbons liquefaction temperature.Light hydrocarbon component liquefaction wherein, its mixed stream enters light hydrocarbon separator 5, and under action of gravity, the lighter hydrocarbons of liquefaction separate with gaseous substance, and the liquefied light hydrocarbon after the separation becomes one of products obtained therefrom and is collected output.Residual gas enters the deep cooling ice chest and further reduces temperature, makes further liquefaction of wherein combustibleconstituents (as methane etc.), enters natural gas liquids separator 6 then, the separation of liquefying once more.The liquefaction of liquefaction output be industry or civilian natural gas liquids, and the residual exhaust that can not liquefy mainly is nitrogen, carbonic acid gas and other rare gas element, from the discharge of natural gas liquids separator top to be used as other processing or as exhaust gas emission.In the petroleum gas treatment scheme, need not pressurize to it, the lighter hydrocarbons of required extraction and Sweet natural gas are all exported with liquid form.In this flow process, twice cooling liquefaction all can produce pressure and reduce, and therefore, relies on this pressure drop with regard to keeping certain input flow rate of processed petroleum gas, with non-stop run.

In the utility model, core component one turbocompressor 3 and 4 and primover by the aerial turbo fan engine Transform Type design or directly the repacking.Turbocompressor 3 and primover are made of a dual-rotor aviation turbofan engine group 11.Its repacking is easy to, need only block the connected entrance between outer culvert passage and the nozzle and on casing over contain the air-flow outlet and draw outer culvert air-flow and get final product.Because, the air property during these turbine engine group 11 operations do not become, working condition is constant, so the aerodynamic parameter of whole engine and not change of thermal parameter, so just only need very little repacking workload, and its controlling organization and controlled variable all need not change, engine operation makes full use of the optimum working efficiency of aircraft engine in former optimum Working.The free power turbine that is connected at aerial turbo fan engine nozzle place 17 has become series product for the standard equipment of present internal combustion turbine terrestrial station, can choose the model that is complementary with used aircraft engine.Turbocompressor 4 and deep cooling expansion turbine 19 can be by another aircraft engine repackings.Remove low-pressure compressor, combustion chamber, nozzle and the fuel oil control accessory case of former engine, the casing place in former install combustion chamber reequips the separation casing that a handlebar pneumatic plant air-flow is drawn volute and turbine airflow injection volute.This separation casing is finished the injection with turbine airflow of drawing of pneumatic plant air-flow.Compressorshaft is connected with work turbine 17, and volute is installed at the nozzle place, draws the cooling air behind turbine expansion, and on volute the output shaft that is connected with turbine is installed, and by output shaft deep cooling expansion turbine 19 is linked to each other with generator 20.Generator 20 can absorb unnecessary energy such as work turbine 17 on the one hand, and the operating mode of regulating turbocompressor 4 on the other hand by exerting oneself of regulator generator 20 is to adapt to the variation of processed petroleum gas component or flow.Regulator generator 20 is exerted oneself and aerial turbo fan engine group 11 working conditions are complementary, and can also reach the cooling condition of regulating low pressure cooling air flow process and middle compacting freezing air flow process respectively, to satisfy best secondary refrigerating coupling.When improving the power of aerial turbo fan engine group 11, increased the refrigerating duty of low pressure cooling air flow process, also increased simultaneously the output rating of work turbine 17, at this moment can increase exerting oneself of generator 20 by regulating simultaneously, press the rotating speed of turbocompressor 4 constant in the maintenance, compacting freezing air flow process operating mode is constant in making.Vice versa.

The waste gas charging turbine principle of using in 15 pairs of the turbo-driven compressor 14 at the utility model center and shallow cold expansion turbines and the ordinary diesel oil machine is the same, kinetic energy when being used for reclaiming the expansion of low pressure cooling air flow process forced air, its design variable can be according to the supercharging system design of large-scale marine diesel engine.Also can use the pneumatic plant and the turbine of existing aerial turbo fan engine to transform.But it should be noted that in transformation because the kinetic energy that expansion turbine 15 is absorbed is little, answer the corresponding load that reduces pneumatic plant, general pressure ratio can only reach 1.5～2.

In the utility model, the principle of work of its device is to use two-stage to freeze to cool off processed petroleum gas.Owing to be indirect cooling, need not compress processed gas, therefore just can save custom-designed special-purpose turbo-driven compressor.Can reduce cost on the one hand, it can adapt to the different components of processed petroleum gas on the other hand, different ratios and different flow.The variation of processed petroleum gas character is very little to its influence.In cooling flow, adopt air to do refrigerant, be not only because can polluted air, and be because can adopt aerial turbo fan engine as compressor, to reduce cost, raise the efficiency.In first step refrigeration cycle, adopt the open type air cycle, make the pressurized air used as refrigerant and unite two into one as total system power primover desired compression air source.Compressor and primover also unite two into one, and have reduced volume, have improved efficient, the more important thing is and can utilize ready-made aerial turbo fan engine, only need carry out the repacking of minute quantity, and the working parameter of engine need not change.In the refrigeration cycle of the second stage, adopt the enclosed air cycle, the air of using as refrigerant recycles.These air are dry airs of crossing through processed, can save dewatering unit on stream like this.In closed cycle, why employing has the air of certain pressure of foundation, this is because the hpc that adopts existing aircraft engine as compressor, is work and the aerodynamic parameter that does not change hpc on the one hand, and an intake pressure the same when originally low-pressure compressor being arranged is provided.Also because the unit volume quality of forced air increases, under the situation of same pressure difference, the refrigerating duty of unit volume refrigerant also just increases, and can dwindle the volume of whole device on the other hand.In middle compacting freezing air loop, air container 18 is housed, land used reduces the fluctuation of air pressure in the loop, also can leak recirculated air and replenish, with steady pressure.

In the utility model, low pressure cooling air flow process is the open type flow process, and its cooling air medium that is used for heat exchange in the precooling ice chest is discharged into atmosphere after heat exchange.The utility model also can adopt semiclosed flow process in low pressure cooling air flow process.It is connected with low-pressure turbine pneumatic plant 3 inlets with pipeline in precooling ice chest 16 refrigerant exits, the air of discharging is introduced turbocompressor 3 circulate.On the duct wall of turbocompressor 3 ingress, drive some auxilairy air intakes.Because when work, have only the outer air-flow of containing to recycle, the intension air communication is crossed the core-engine work by combustion, therefore, must replenish outside air and just can keep normal work before low-pressure compressor 3.Use the semiclosed loop flow process can reduce the dehydration burden.

The petroleum gas treatment unit that it is 1,000,000 standard cubic meter that the utility model is used to set up a day output.Can use the SPEY512 aircraft engine repacking of two Britain sieve sieve (ROLLS-ROYCE) company, wherein press and expansion turbine in the air flow process are pressed in removal low-pressure compressor and combustion chamber etc. in transforming as.Work turbine can be selected the RT46 work turbine for use.In low pressure cooling air flow process, can obtain 50 ℃～60 ℃ the temperature difference, in middle compacting freezing air flow process, can obtain the temperature difference more than 140 ℃.Like this, can make processed gas reduce to 120 ° below the K, reach the natural gas liquefaction temperature from 300 ° of K～310 ° K.

Claims

1, a kind of separating unit for liquefying petroleum gas, it has air heat exchanger 1 and 2, turbocompressor 3 and 4, light hydrocarbon separator 5 and liquefied natural gas separator 6, it is characterized in that: hpc 7 is arranged, combustion chamber 8, high-pressure turbine 9, low-pressure turbine 10, turbocompressor 3 and hpc 7, combustion chamber 8, high-pressure turbine 9 and low-pressure turbine 10 have been formed a dual-rotor aviation turbofan engine 11, turbocompressor 3 is the low-pressure compressor of aerial turbo fan engine 11, the outer culvert air-flow that this low-pressure turbine pneumatic plant 2 is compressed is the low pressure cooling air, outside in the low pressure cooling air flow process of Haning, air water separator 12 and 13 are arranged, air water separator 12 and 13 input aperture ends are connected on the delivery port end of air heat exchanger 1 and 2 respectively, after air water separator 12, be connected to the turbo-driven compressor 14 that drives by shallow cold expansion turbine 15, behind shallow cold expansion turbine 15, precooling ice chest 16 is arranged, the nozzle place of dual-rotor aviation turbofan engine 11 is connected to work turbine 17, work turbine 17 links to each other with turbocompressor 4, and be connected to deep cooling expansion turbine 19 and generator 20, behind turbocompressor 4 air-outs, be connected to air heat exchanger 21, connect precooling ice chest 16 gas input port that is cooled afterwards, precooling ice chest 16 gas delivery port that is cooled is connected to the air-in of deep cooling expansion turbine 9, behind its delivery port, be serially connected with deep cooling ice chest 22, in cold case 23, and by in cold case refrigerant delivery port take back turbocompressor 4 inlet mouth places, 4 inlet mouth places also are connected to the air container 18 that can store certain air at turbocompressor, 19 groups of turbocompressor 4 and deep cooling expansion turbines are for having removed the aerial turbo fan engine of low-pressure compressor and combustion chamber and fuel oil control accessory case, the cold case 23 gas inlet end that is cooled during processed petroleum gas input aperture directly is connected to, its exit end is connected to light hydrocarbon separator 5 input apertures, light hydrocarbon separator 5 gas output ends are connected to the gas inlet end that is cooled of deep cooling ice chest 22, and exit end is connected to the input terminus of natural gas liquids separator 6.

2, separating unit for liquefying petroleum gas as claimed in claim 1, it is characterized in that: in low pressure cooling air loop, pipe connection is arranged in low-pressure turbine pneumatic plant 3 ingress in the outlet of precooling ice chest 16 refrigerants, and have the auxilairy air intake that is used for replenishing air that communicates with atmosphere at the ingress duct wall.