50 results about "Bog" patented technology

Carbon dioxide re-liquefaction may be provided by a system capable of receiving a vented boiled off gas stream from a storage vessel at a first compressor; compressing the vented BOG stream at the first compressor into a first compressed BOG stream at a first pressure and a second compressed BOG stream at a second pressure, greater than the first pressure; cooling the first compressed BOG stream in a heat exchanger to produce a liquid stream by: cooling, via a refrigerant unit, the second compressed BOG stream to produce a first cold stream, of a temperature less than that of the first compressed BOG stream; exchanging heat from the first compressed BOG stream against tire first cold stream; and returning the liquid stream to the storage vessel.

A gas supply and carbon capture system, comprising an LNG tank, a BOG compressor set, a dual-fuel engine, a CO2 capture unit, a CO2 compressor, a heat exchanger, and a CO2 storage tank, wherein the LNG tank is used for storing liquid LNG, BOG formed at the inner top of the LNG tank is fed to a cold side of the heat exchanger; the heat exchanger is used for heat exchange between pressurized CO2 and the BOG, cold energy of the BOG is utilized to liquefy the CO2, the obtained liquid CO2 is stored in the CO2 storage tank, and the BOG having a higher temperature after the heat exchange is sent to the BOG compressor set; and the BOG compressor set is used for pressurizing the BOG having a higher temperature and then delivering the BOG to the dual-fuel engine for combustion, and the BOG compressor set employs normal-temperature compressors. By means of the system, the cold energy of the BOG from the LNG tank is fully utilized, and the temperatures of the BOG entering the BOG compressors are caused to meet an inlet temperature requirement of the normal-temperature compressors.

The present invention relates to a special sampling device for soil in a peat swamp wetland, comprising a base plate, a slide plate symmetrically arranged on the bottom of the base plate, an arc-shaped pressure plate arranged on the rear side of the bottom of the base plate through a bracket, a push handle arranged on the front side of the top of the base plate, a drilling mechanism arranged on a fixed plate and the center of the base plate, a sampling mechanism arranged in the drilling mechanism, and a cleaning mechanism arranged in the sampling mechanism; the present invention can solve the following existing problems: the present invention separates and collects soil and moisture in a storage cylinder and a storage cover through the cooperation of a moving tube and a hollow round cake, and then cleans the storage cylinder and the storage cover with the collected water after the sampling is completed, thereby preventing residual soil from contaminating the sample; the present invention realizes sampling of soil at different depths in a peat swamp through the cooperation of an arc groove and an arc-shaped sampling plate, thereby reducing the labor intensity of staff; and also prevents soil from entering the cylinder and contaminating the inner wall of the cylinder through the cooperation of a strip block and a mud guard.

The application provides a method for rapidly distinguishing coal rock sedimentary environment by using ash yield and total sulfur content, comprising the following steps: drawing an ash yield-total sulfur content relationship diagram of coal rock; obtaining ash yield data and total sulfur content data of a coal rock sample to be measured; and explaining the sedimentary environment of the coal rock sample to be measured according to the position area of the ash yield data and the total sulfur content data of the coal rock sample to be measured on the ash yield-total sulfur content relationship diagram. The application distinguishes the sedimentary environment of the coal rock sample to be measured according to the position area of the ash yield data and the total sulfur content data of the coal rock sample to be measured on the ash yield-total sulfur content relationship diagram. The distinguishing method of the application is simple in steps, can clearly and intuitively make an efficient judgment on whether the peat bog type in the coal rock sedimentary environment is affected by marine transgression, the test data is convenient to obtain, is not affected by subjective factors, and the distinguishing result is relatively accurate.

The present invention relates to the production of propagation plugs, primarily blocks of growth medium for the growing of cuttings and seed plants, and of the type consisting of a cylindrical block having an envelope of sheet material and an associated filling of sphagnum or a corresponding substrate material. The sheet material is here a netting or mesh, preferably biodegradable, having a mesh size within the range of 0.1 to 1.5 mm.

FIELD: agriculture.SUBSTANCE: used in growing plants in phytomodules, in “carpet” and container vegetal walls. The substrate for growing plants in vertical phytostructures includes expanded vermiculite, zeolite-containing tripoli from the Khotynetsky deposit, and deoxidized high-moor peat, in the stated quantitative ratio.EFFECT: production of light, nutritious, loose, breathable soil that retains moisture well, contains silicon necessary for plants in a form accessible to them, and has a high ion-exchange capacity.1 cl, 1 tbl, 2 ex

This application provides a method for improving the thermal efficiency of a BOG reliquefaction system, comprising: analyzing the interaction between energy loss and temperature difference values ​​using a support vector regression algorithm to obtain a balance model between energy loss and temperature difference; optimizing the heat transfer temperature difference control parameters using a gradient descent algorithm for the adjusted compression parameter set to obtain an optimized temperature difference control scheme; simulating the overall system efficiency under the interaction of equipment using the optimized temperature difference control scheme to determine whether the simulated efficiency meets a preset standard; if the simulated efficiency does not meet the preset standard, iteratively updating the parameters and adjusting the optimization path according to the energy loss reduction requirement to obtain an iteratively optimized path; applying the iteratively optimized path to the gas reliquefaction system in real time to determine whether the energy consumption cycle is broken, and obtaining the final system thermal efficiency index.

The application provides a method and system for controlling the generation of BOG boil-off gas, comprising the following steps: S1, analyzing and obtaining all influence parameters related to the generation of BOG boil-off gas; S2, screening all influence parameters by using a preset filter to obtain the influence parameters that can be calculated, adjusted and most economical; and S3, taking the screened influence parameters as adjustable parameters to suppress the generation of BOG boil-off gas. The application suppresses the generation of BOG boil-off gas, and reduces the generation of BOG boil-off gas from the source before the recovery of BOG boil-off gas.

The application provides a system for processing excess BOG of an LNG ship, and belongs to the technical field of ships.The system comprises a BOG supply system, an excess BOG utilization system, a flue gas energy storage system, a flue gas energy release system and an inerting system.Based on the complex sailing conditions of a ship, when the LNG ship sails at low load, sails in a maneuvering mode or is anchored, the excess BOG generated in the LNG liquid cargo tank is sent into a boiler for combustion, and then the energy of the excess BOG is converted into the pressure energy of flue gas and stored through a series of devices, so that the problem of waste of the BOG in the excess state is effectively solved; when the ship sails at high load or is unloaded at a discharge port, the energy of the flue gas is released, so that the energy of the BOG is reused.In addition, the stored flue gas can also be used for inerting of low-temperature pipelines and equipment at normal temperature or at a temperature of 0 DEG C to -60 DEG C, so that the inerting cost of the ship is reduced.

The present application relates to the technical field of image processing, in particular to a peat bog information extraction method and system based on GIS remote sensing image. The method collects multi-temporal optical remote sensing image, DEM data and pixel precipitation, pre-processes the multi-temporal optical remote sensing image, and performs semantic segmentation to identify the region of interest; the DEM data is analyzed for elevation characteristics to extract pixel slope and pixel convergence accumulation, the precipitation uniformity is calculated based on the pixel precipitation, and the pixel slope and pixel convergence accumulation are weighted and fused to screen the peat formation potential area; the coupling delay index is calculated based on the time delay of the vegetation green peak and the water supply trend peak value to screen the peat bog suspected area; the area threshold is screened to obtain the target peat bog area and output the result. The present application combines the differences between peat bog and ordinary bog in multi-dimensional characteristics, extracts patches with peat layer characteristics, and avoids misjudgment of peat bog relying on spectral feature recognition.

A method of cooling and reliquefying a boil off gas (BOG) stream (901) from a liquefied carbon dioxide cargo stored in a tank or tanks (101) on a floating transportation vessel. The method comprises at least the following steps: • compressing the BOG stream (901) from the liquefied carbon dioxide cargo tank (101) in one or more stages of BOG compression (102, 103) to provide a compressed BOG discharge stream (906); • cooling the compressed BOG discharge stream (906) against a carbon dioxide refrigerant stream (918) to provide a cooled compressed BOG stream (907); and a warmer carbon dioxide refrigerant stream (911); • compressing the warmer carbon dioxide refrigerant stream (912) in one or more stages of refrigerant compression (106, 107) to provide a compressed carbon dioxide refrigerant discharge stream (916) for subsequent use as the carbon dioxide refrigerant stream (918), which is operable to cool and at least partially condense the compressed BOG discharge stream (907). The one or more stages of BOG compression (102, 103) and the one or more stages of refrigerant compression (106, 107) are provided by a single shaft multistage compression unit.

The invention relates to the technical field of energy conservation, in particular to a treatment system for recycling oil gas and BOG through BOG low-temperature cold energy cycle condensation. Emptying treatment of BOG and oil gas in an LNG oil gas combined building station can cause the problems of serious environmental pollution, environmental safety and resource waste. In order to solve the technical problems, the treatment system for recycling oil gas and BOG through BOG low-temperature cold energy cycle condensation of the LNG oil gas co-construction station is provided, on the basis of normal-temperature compression and normal-temperature water cooling, oil gas discharged in the operation process of the refueling part of the co-construction station is recycled only through low-temperature cold energy condensation of BOG discharged by an LNG storage tank; condensed exhaust gas meets the national environmental protection emission requirement, and the oil gas recovery rate reaches 99% or above, so that in the oil gas recovery process, a tail gas adsorption link does not need to be arranged, a refrigerating system does not need to be additionally arranged, and potential safety hazards and operation investment cost of oil gas recovery are greatly reduced.

The application discloses a BOG reliquefaction large refrigeration system based on reverse Brayton cycle and an operation method thereof. The system comprises a large reverse Brayton cycle refrigeration system and a BOG reliquefaction system. The large reverse Brayton cycle refrigeration system comprises an expander, a first motor, a first compressor, a bearing, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a second compressor and a second motor. The BOG reliquefaction system comprises a liquefied natural gas storage device, a mechanical pump and a spray tower. The outlet of the liquefied natural gas storage device is connected with the mechanical pump and the second inlet of the fourth heat exchanger in sequence, the second outlet of the fourth heat exchanger is connected with the inlet of the spray tower, and the outlet of the spray tower is connected with the inlet of the liquefied natural gas storage device. The application avoids energy loss in the phase change process through the reverse Brayton cycle, and can reduce the overall operation cost compared with the traditional BOG treatment system.

The present invention discloses a method and related device for predicting the generation amount of liquefied BOG in an LNG storage tank based on heat exchange, belonging to the technical field of production prediction, including: obtaining the adiabatic performance parameters of the LNG storage tank, the thermophysical properties parameters of the LNG, and the structural parameters of the LNG storage tank; constructing a dynamic model of internal heat exchange in the LNG storage tank; obtaining the stratified temperature gradient of the liquid phase in the LNG storage tank and the stratified temperature gradient of the gas phase in the LNG storage tank, and obtaining the external surrounding environment parameters of the LNG storage tank; inputting the stratified temperature gradient of the liquid phase in the LNG storage tank, the stratified temperature gradient of the gas phase in the LNG storage tank, and the external surrounding environment parameters of the LNG storage tank into the dynamic model of internal heat exchange in the LNG storage tank, predicting the BOG generation rate of each height layer in the LNG storage tank, and calculating the total BOG generation amount of the LNG storage tank according to the BOG generation rate of each height layer in the LNG storage tank. This method and related device can accurately predict the BOG generation amount of the LNG storage tank.

The utility model discloses a bog reed rhizosphere soil collecting device, and belongs to the technical field of soil collection. The inner net basket is placed in the outer barrel, a gap is formed between the outer side wall of the inner net basket and the inner side wall of the outer barrel, and the outer side wall of the inner net basket is wrapped with a first gauze element; the center column is fixedly connected to the center of the interior of the inner net basket, a plurality of second gauze pieces are fixedly connected between the center column and the inner side wall of the inner net basket, and the inner space of the inner net basket is divided into a plurality of planting areas by the second gauze pieces. The single reed rhizosphere soil collecting device can collect rhizosphere soil of a single reed, facilitates statistics of various growth indexes of individuals, and improves the accuracy of test data.

The invention discloses a method for pre-cooling an LNG (Liquefied Natural Gas) loading pipeline by utilizing BOG (Boil Off Gas), belongs to the technical field of LNG, and aims to solve the problems of LNG loss, high cost, complicated operation, difficulty in thermal stress management and the like in the conventional pre-cooling method. According to the method, flow paths (isolating a main LNG source) from a BOG source (such as an LNG storage tank steam space) to an inlet of a pipeline and from an outlet of the pipeline to a BOG treatment system are established, BOG is led in to flow through the pipeline and is cooled by cold energy of the BOG, and the heated BOG is led out for treatment. And by monitoring the pipe wall temperature, calculating the cooling rate and / or the temperature gradient in real time, comparing the cooling rate and / or the temperature gradient with a preset limit value and dynamically adjusting the flow velocity of the introduced BOG, accurate control over the cooling process is achieved, thermal stress is effectively managed, and pipeline damage is avoided. The BOG cold energy is utilized, LNG loss is remarkably reduced, the operation cost is reduced, operation is simplified, safety controllability is improved, and environmental emission is reduced.

The invention discloses a control method and system for processing liquefied natural gas flow at an LNG leading-in terminal, and relates to the technical field of liquefied natural gas, and the control method comprises the steps of obtaining LNG terminal information, obtaining LNG historical transmission data according to the LNG terminal information, obtaining a BOG temperature influence coefficient according to the LNG historical transmission data, and obtaining BOG compression power parameter information according to the LNG terminal information. According to the method, the generation conditions of the BOG at different temperatures in the LNG storage structure of the LNG terminal are accurately analyzed through the BOG temperature influence coefficient, a basis is provided for follow-up LNG transmission control, the LNG control efficiency is improved, LNG transmission is controlled through LNG transmission speed information, the stability and reliability of LNG transmission are ensured, and the method is suitable for popularization and application. And overpressure or decompression caused by too high or too low transmission speed is avoided, the BOG compression power is ensured to be adjusted in time while the BOG compression power adjusting frequency is reduced through the BOG compression power adjusting period, and the stability of LNG is ensured.

This disclosure relates to a BOG reliquefaction system, a method for reliquefying BOG in a reliquefaction system, and a method for operating a BOG reliquefaction system. The BOG reliquefaction system includes at least one liquefied natural gas (LNG) container, a BOG preheater, at least one BOG compressor having a BOG compressor cooler, and a BOG recondenser having a refrigeration cycle. The BOG reliquefaction system includes a separate liquid circuit with circulation of a liquid phase heat transfer fluid (HTF) to preheat the BOG from the LNG container before it enters the BOG compressor. The separate liquid circuit includes: a liquid pump configured to pump the HTF; a BOG preheater configured to perform heat exchange between the BOG and the HTF; a BOG recondenser located downstream of the BOG preheater; and a liquid trimming heater located downstream of the BOG recondenser configured to heat the HTF.

The invention discloses a BOG reliquefaction recovery processing method and system, and the BOG reliquefaction recovery processing method comprises the following steps: when the water dew point of BOG raw material gas processed by a raw material gas drying device is smaller than a first preset value, the BOG raw material gas enters a liquefaction cold box device; adjusting a liquefaction cold box device, a refrigerant matching device and a refrigerant compression device, and circularly providing different cold quantities for the multi-level cold sections of the liquefaction cold box through multi-level compression of the refrigerant compression device and multi-level expansion cooling coupling of a corresponding expansion mechanism until the temperature of a backflow refrigerant reaches a first preset value; the treated BOG raw material gas is subjected to multi-level cooling by a liquefaction cold box device to form LNG (Liquefied Natural Gas); and the output quantity of the refrigerant compression device is adjusted to the maximum value, the refrigerant adding quantity is increased, the opening degree of an HV-1 throttling valve is increased, liquid in the denitrification flash evaporation device is controlled to be within a fifth threshold value range, and LNG is subjected to flash evaporation separation through the denitrification flash evaporation device and recycled into the LNG storage tank. The system and the method have the beneficial effects that BOG feed gas is liquefied to form LNG, and rapid recovery of BOG is realized.

The utility model relates to the technical field of cold insulation systems, in particular to an LNG (Liquefied Natural Gas) storage tank closed cold insulation system utilizing BOG (Boil Off Gas) cold energy. According to the technical scheme, mainly aiming at the problem of BOG cold energy waste caused by the fact that the cold energy of BOG is not utilized due to the fact that a direct compression process is adopted for BOG, the BOG cold energy recycling device comprises an LNG storage tank, an outer tank is arranged on the outer side of the LNG storage tank in a sleeving mode, a space is reserved between the LNG storage tank and the outer tank and used for flowing of cooling liquid, a liquid discharging pipe is arranged at the bottom of the outer tank, and the liquid discharging pipe is communicated with the LNG storage tank. A liquid inlet pipe is further mounted at the top of the outer tank; and the spraying assembly is arranged on the LNG storage tank and is used for uniformly discharging the cooling liquid. According to the LNG storage tank, the cooling capacity in BOG generated by evaporation of the liquefied natural gas in the LNG storage tank can be effectively utilized, meanwhile, the liquefied natural gas in the LNG storage tank is cooled, and potential safety hazards caused by the fact that the temperature of the liquefied natural gas is too high and the evaporation capacity is too large are effectively prevented.

This application relates to the fields of remote sensing image processing and ecological environment monitoring technology, and discloses a method for extracting peat bog information based on the dense temporal characteristics of multi-source remote sensing. The method includes acquiring time series of microwave radar and optical vegetation index, performing alignment and cleaning, extracting low-frequency and continuous first-order derivative sequences from the microwave radar to generate temporal basis features; extracting historical delay features for effective optical observation times, splicing the basic state term and derivative modulation product term to generate a bilinear distributed lag observation matrix; performing scale unification processing on the lag observation matrix, constructing a diagonal regularized matrix based on time-lapse attenuation characteristics, and solving for the solution vector; calculating the normalized asymmetric hysteresis intensity and reconstruction quality factor, and combining dual thresholds to determine the output distribution data. This invention incorporates the physical hysteresis effect of hydrological evolution into the computational framework, overcoming multicollinearity and observation sparsity problems, and achieving high-precision extraction of peat bogs.

The utility model relates to the technical field of liquefied natural gas sampling analysis, and provides an LNG sampling system for a filling ship, the system comprises an LNG pipeline and a BOG pipeline, the LNG pipeline is communicated with an LNG sampling assembly, a vaporization assembly and a gas quality analysis assembly in sequence, the LNG sampling assembly is used for being connected to a liquid phase header pipe to take out an LNG sample in the liquid phase header pipe, and the BOG pipeline is used for being connected with the vaporization assembly. The vaporization assembly is used for vaporizing the LNG sample; the BOG pipeline is sequentially communicated with a BOG sampling assembly and a gas mass analysis assembly, and the BOG sampling assembly is used for being connected to a gas phase header pipe so as to take out a BOG sample in the gas phase header pipe; and the gas quality analysis assembly is used for respectively carrying out online analysis on the gasified LNG sample and BOG sample. According to the utility model, the BOG pipeline is arranged outside the LNG pipeline, so that the LNG sample and the BOG sample can be sampled and analyzed at the same time, and the metering error caused by only considering the single-state gas can be avoided.

The invention discloses an efficient and energy-saving ammonia gas replacement and recovery system, and relates to the technical field of ship construction. The system comprises an ammonia storage tank, an ammonia supply pipeline and a BOG recondensation pipeline, the ammonia storage tank is connected with the ammonia supply pipeline, and the ammonia supply pipeline comprises a low-pressure pump, a front buffer tank, a BOG cooler, a high-pressure pump, a liquid ammonia heater, a valve group control unit and a host which are sequentially connected; the ammonia storage tank is connected with the BOG recondensation pipeline, and the BOG recondensation pipeline comprises an ammonia vapor buffer tank, a BOG compressor, a BOG cooler and a liquid ammonia recovery buffer tank. The BOG cooler is arranged in front of the high-pressure pump of the ammonia supply pipeline, ammonia vapor in the BOG recondensation pipeline is deeply cooled through cold energy of liquid ammonia in the ammonia supply pipeline, meanwhile, the liquid ammonia is heated through heat energy of the ammonia vapor in the BOG recondensation pipeline, and the energy utilization rate of the ammonia vapor recovery process of the ship ammonia tank is effectively increased.

When the ventilation mast for the LNG ship is used, the lifting driving piece is adjusted according to the concentration of BOG, so that the lifting driving piece drives the lifting cover to move in the direction close to or away from the main body, and the size of a discharging channel formed between the lifting cover and the main body is adjusted so as to adapt to the concentration of the BOG, and air of the BOG can be rapidly discharged to the outside conveniently. Meanwhile, when the wind power in the air is large, the lifting cover is driven to be close to the main body through the lifting driving piece so as to shrink the discharging channel, so that the discharging channel forms a narrow pipe effect under the action of the wind power, the air pressure at the discharging channel is lower than the air pressure in the air discharging channel, and then the discharging efficiency of BOG is improved.

The utility model provides an operation device for recycling and quickly discharging liquid by utilizing BOG (boil-off gas), which comprises a plurality of liquid discharging pries arranged in parallel, and the plurality of liquid discharging pries are connected through flat pressing pipelines; each liquid unloading pry comprises a gasifier used for gasifying LNG, a pressurizing liquid outlet pipeline connected with a liquid inlet of the gasifier, a first gas phase pipeline connected with a gas outlet of the gasifier and a second gas phase pipeline used for conveying BOG, and the second gas phase pipeline passes through a first manual valve and then is divided into a first branch pipe to be connected with the flat pressing pipeline. According to the operation device for rapidly discharging the liquid through BOG recovery, the gasification pressurization time is shortened, the liquid discharging efficiency of an LNG storage and distribution station is improved, and the risk of explosion caused when residual BOG natural gas in a storage tank vehicle is emptied on site is reduced.

The present invention relates to the technical field of BOG gas recovery in natural gas liquefaction plants, and particularly to a helium extraction process for high-nitrogen-containing BOG gas. In the helium extraction process for high-nitrogen-containing BOG gas of the present invention, first, the BOG raw gas after gasification and compression is subjected to catalytic dehydrogenation treatment, effectively solving the problems that when the crude helium is extracted by the cryogenic method first and then catalytic dehydrogenation is carried out, due to the high enrichment concentration of hydrogen in the crude helium, the catalytic reaction temperature is relatively high. After the catalytic dehydrogenation treatment, low-temperature double-column rectification is carried out to extract crude helium. The concentration of the crude helium obtained from the first rectification column can reach more than 95%, which is more conducive to extracting higher-purity helium. Most of the nitrogen in the BOG gas can be removed through the second rectification column, and a small amount of nitrogen can be further removed in the low-temperature PSA adsorption high-purity helium extraction mechanism, thereby avoiding the circulation of nitrogen back to the LNG liquefaction system with the BOG, and further reducing the energy consumption of the LNG liquefaction system. Finally, the extracted crude helium is subjected to low-temperature PSA adsorption treatment to obtain high-purity helium.

The invention discloses a coal rock distribution prediction method and device, electronic equipment and a storage medium. The coal rock distribution prediction method comprises the following steps: determining target topographic factor information of a micro-ancient landform formed by a target coal rock stratum, the topographic factor information being a micro-ancient landform shape represented by a stratum inclination angle and a stratum curvature, the topographic factor information can be used for representing peat marsh facies characteristics which are required by the coal rock stratum in a sedimentary environment and have a positive promotion effect on coal rock stratum deposition; determining seismic wave impedance corresponding to the target coal rock stratum; and carrying out seismic inversion based on the target terrain factor information and the seismic wave impedance corresponding to the target coal rock stratum, and predicting to obtain a coal rock distribution result of the target coal rock stratum. According to the scheme, the seismic inversion is constrained and verified by the topographic factor information of the micro-ancient landform and the seismic wave impedance of the target coal rock stratum, and the accuracy of a coal rock distribution prediction result is improved.

The application discloses a BOG processing tool assembly and a processing method, and relates to the field of BOG processing tools.The BOG processing tool assembly comprises a BOG gas phase pipeline, a high-pressure natural gas pipeline, a medium-pressure natural gas pipeline and an injection pipe group.The injection pipe group is provided with an adjustable ejector, and the injection pipe group is provided with an air inlet end, an air outlet end and a flow guide end.The air inlet end of the injection pipe group is communicated with the high-pressure natural gas pipeline, the flow guide end of the injection pipe group is communicated with the BOG gas phase pipeline, and the air outlet end of the injection pipe group is communicated with the medium-pressure natural gas pipeline.In this way, the adjustable ejector of the injection pipe group can mix BOG gas in the BOG gas phase pipeline and high-pressure natural gas in the high-pressure natural gas pipeline to obtain medium-pressure natural gas, and the medium-pressure natural gas is sent out through the medium-pressure natural gas pipeline, while the BOG gas is sucked into the adjustable ejector, which does not need power (the power relies on the negative pressure generated when the high-pressure natural gas jet flow in the adjustable ejector), and the mixing effect of the BOG gas phase and the high-pressure natural gas is good.

The invention belongs to the technical field of BOG treatment, and particularly discloses a flow-controllable BOG recondensation device and a recondensation process. The BOG re-condensing device has an excellent pre-cooling function, the inlet steady flow straight pipe section and the BOG inlet chamber are jointly matched to form a shell-and-tube structure, BOG can be efficiently pre-cooled before LNG and BOG are mixed, the BOG with the lower temperature is more easily condensed and liquefied when the BOG and the LNG are in direct contact in the gas-liquid mixing condensing chamber, and the re-condensing efficiency is improved; through the combination of the perforated plate and the hole plug, the flow can be controlled and adjusted, the anti-interference capability of the after-condenser is improved, and the application range of the after-condenser is widened; the multi-hole multi-nozzle design obviously increases the contact area of the LNG and the BOG in the gas-liquid recondensation mixing chamber, meanwhile, the turbulence disturbance between the BOG and the LNG is enhanced, and the BOG recondensation efficiency is improved to a great extent. According to the BOG recondensation process provided by the invention, the process flow can be simplified, LNG pressure energy and cold energy can be fully utilized, and energy consumption can be greatly reduced, so that the BOG recondensation process has very good energy-saving and emission-reducing effects.

The present invention proposes a compression-expansion integrated system and its BOG reliquefaction method, including a BOG precooler for precooling the BOG gas from the upper part of the LNG storage tank to a low temperature; a compression-expansion integrated machine, which is arranged in a low-temperature cavity and includes at least one set of compressor components and at least one set of expander components, the compressor components compress the precooled BOG gas, and the expander components expand and cool the compressed BOG gas; a multi-stage heat exchanger, one end of which is connected to the discharge port of the expander component, for heat exchange and cooling the expanded BOG; wherein the compressor component and the expander component are connected by low-temperature bearings and magnetic coupling transmission, and are arranged in the same low-temperature cavity. This application realizes efficient reliquefaction treatment of BOG gas through compression-expansion integrated design and adaptive control, and the system energy consumption is reduced by about 40% compared with the traditional process, which greatly improves the cold recovery efficiency and operation stability.