71results about How to "Short renovation period" patented technology

The present invention relates to coal burning boiler in thermal power plant, and is especially judgment method for high temperature corrosion degree of boiler water cooling wall in large power station. The present invention features that the judgment includes first determining the main factors of affecting the high temperature corrosion of water cooling wall; then determining measuring conditions and relevant measuring parameters; and final rating to high temperature corrosion trend of water cooling wall via grey clustering procedure. The present invention makes it possible to grasp high temperature corrosion degree of boiler at all time for taking measures timely and to select apparatus reforming scheme with optimal performance / cost ratio.

The invention discloses an optimization method and an optimization system of SCR denitrification intelligent ammonia injection based on soft measurement and predictive control. The method comprises the following steps: firstly, establishing an entrance nitrogen oxide concentration model based on operation data; then utilizing the model and currently-collected operation data to obtain a predicted value; secondly, calculating the ammonia injection amount at the current operation condition as a feedforward signal according to an entrance nitrogen oxide concentration predicted value and transmitting the feedforward signal of the ammonia injection amount to an SCR denitrification system; thirdly, measuring a measured value of exit nitrogen oxide concentration of a coal-fired generation unit combustion system, making deviation between the measured value and an entrance nitrogen oxide concentration set value and inputting a difference value into a prediction controller, obtaining a feedback control signal of the ammonia injection amount based on the deviation and transmitting the feedback control signal to the SCR denitrification system by a prediction controller; fourthly, controlling the ammonia injection amount of an SCR denitrification reactor according to the feedforward signal of the ammonia injection amount and the feedback control signal of the ammonia injection amount by theSCR denitrification system. The system disclosed by the invention has the advantages of higher response rate, lower investment, short transformation period and the like.

The invention discloses a distillate yield improving vacuum distillation method and device. A flash vaporization vessel is arranged on an oil transfer line between a vacuum furnace and a vacuum distillation tower. Vacuum distillation raw materials enter the oil transfer line and the flash vaporization vessel after being heated by the vacuum furnace. Gas liquid separation is carried out in the flash vaporization vessel: liquid discharged from the bottom of the flash vaporization vessel, namely flash bottom oil, is introduced into the vacuum distillation tower; and gas discharged from the top of the flash vaporization vessel, namely flash top gas, is led out of the device after being condensed into liquid. According to the vacuum distillation method and device with the flash vaporization vessel arranged behind the vacuum furnace, on one hand, the yield of vacuum distillate is increased, on the other hand, a conventional decompression oil transfer line low-speed section is omitted, the operation load of the vacuum tower is reduced, and the diameter of the vacuum tower can be appropriately reduced, so equipment investment is saved, and the operating cost is reduced.

The invention provides a target control method for a heating power generation system. The target control method is suitable for various models and capacities of condensing steam turbines used for heating in all heating areas and safely realizes zero cold source heat loss in the heating of steam turbine condenser circulating water within the normal exhaust temperature range on the premise of not needing to reconstruct a steam turbine body, and the method has the beneficial effects that the effects of saving energy, saving the funds and shortening the construction period are realized for enterprises, the environment is protected, and the haze is reduced. During the heating of the circulating water, a unit can also participate in the peak shaving of a power grid and make the power grid operate more safely and stably. The heating radius of a hot water network exceeds the heating radius generated by means of the prior art and can reach 120-150 km. Meanwhile, a mathematic model is established to solve the operating parameter target values with the golden section algorithm, and the control with the highest energy supply efficiency as the target is achieved. The solution to the target values is more accurate, and scientific control measures are used to ensure the optimized, safe and reliable operation of the heating power generation system.

The invention discloses a crude oil processing method, which comprises normal-pressure distillation and reduced-pressure distillation, wherein the heavy oil at the bottom of a normal-pressure distillation tower, namely normal bottom oil, is mixed with part of circular reduced-pressure residual oil at the bottom of a reduced-pressure distillation tower, the mixture enters a flash tower, and a top gas phase, namely flash top gas, of the flash tower undergoes heat exchange and is condensed into a liquid phase to be discharged out of the device as a product; and bottom oil, namely flash bottom oil, of the flash tower, is heated in a reduced-pressure furnace to 390 to 420 DEG C, the heated bottom oil is intruded into a flash section of the reduced-pressure distillation tower from a reduced-pressure oil transfer line for reduced-pressure distillation, proper distillate product is drawn from a side line of the reduced-pressure distillation tower, part of reduced-pressure residual oil drawn out from the bottom of the reduced-pressure distillation tower is circulated, and another part of the reduced-pressure residual oil is discharged of the device. Compared with the prior art, the method can effectively improve the drawing rate of a reduced-pressure distillation process and can reduce the load of the reduced-pressure furnace and the reduced-pressure distillation tower at the same time.

The invention, specific to the problem that a flue gas flow field in an absorption tower is nonuniform so that desulfurizing reaction efficiency is decreased, provides a dual-scale dynamic feedback homogenizing system for a flow field. The system comprises a horizontal dynamic rectification component, a longitudinal dynamic rectification component and a fixed diversion unit, wherein the horizontaldynamic rectification component and the longitudinal dynamic rectification component both comprise a flow field adjusting unit and a feedback control unit; the system is installed at an upstream flueof the inlet of the absorption tower, a longitudinal flow field adjusting unit is installed at an inlet segment, which is close to the adsorption tower, of a joining flue in front of the tower, a horizontal flow field adjusting unit is arranged at the upstream of the vertical flow field adjusting unit, and the fixed diversion unit is installed in a swerving flue in front of the tower; the flow field adjusting unit is provided with a blade group for adjusting a flow field, the feedback control unit is used for collecting flow field information at the downstream of the flow field adjusting unit, the angle of deflection of the blade group is adjusted according to feedback information, and the system can be used for realizing homogenizing adjustment of the flow field.

The invention discloses a crude oil pressure-reduced distillation method and a crude oil pressure-reduced distillation device. A flash tower is arranged between a reduced-pressure furnace and a reduced-pressure distillation tower, an oil transfer line is eliminated, a reduced-pressure distillation raw material is heated in the reduced-pressure furnace and directly enter the flash tower, a small amount of stripping gas is introduced into the flash tower, and the liquid phase, namely flash bottom oil, obtained by gas-liquid separation in the flash tower is introduced into the reduced-pressure distillation tower; and a gas phase, namely flash top gas, discharged from the top of the flash tower is condensed into a liquid phase to be led out of the device. A high-temperature hydrogen or inert gas is introduced into the bottom of the flash tower. When the pressure-reduced distillation method and the pressure-reduced distillation device, in which the flash tower for high-temperature hydrogen or inert gas stripping flash tower is arranged behind the reduced-pressure furnace, are used, the yield of a reduced-pressure fraction oil is increased, the conventional reduced-pressure oil transfer line is not used, the operation load of the reduced-pressure furnace is lowered, and the tower diameter of the reduced-pressure tower can be reduced properly; therefore, equipment investment is reduced, and operation cost is reduced.

The invention discloses an efficient steel roll transportation system. A steel roll bearing device, a conveying track, a circulation track, a transverse moving conveying device, a rapid conveying trolley and a PLC control system are included. The circulation start end of the circulation track communicates with the tail end of the conveying track. The circulation track comprises a first vertical track and a second vertical track which are arranged in parallel. Each of the first vertical track and the second vertical track is provided with at least one circulation trolley capable of moving up and down on each of the first vertical track and the second vertical track. A plurality of transverse tracks horizontally arranged in parallel are arranged between the first vertical track and the second vertical track and provided with unloading trolleys capable of moving front and back along the transverse tracks. The equipment base occupied width is small, the depth is small, construction difficulty is low, and economical efficiency is higher.

The invention discloses an annular kiln with a movable flat top. The annular kiln with the movable flat top comprises a kiln body, a kiln crown and kiln walls arranged on the two sides. Compared with the prior art, the annular kiln with the movable flat top is characterized in that the kiln crown is the movable flat top, wherein the movable flat top is formed by detachably connecting a plurality of steel structural frames which are in lap joint with one another; each steel structural frame is provided with idler wheels, wherein the idler wheels are matched with tracks arranged at the upper ends of the kiln walls; the lower end face of the movable kiln crown is provided with an insulating layer; a hot gas recycling pipeline is arranged on the kiln crown. The annular kiln with the movable flat top has the advantages of saving money, and being convenient to place, high in degree of mechanization, capable of lowering labor intensity for workers and improving work efficiency, good in heat preservation effect when green bricks are fired, high in rate of finished products, rapid in cooling speed, easy to cool for brick taking, convenient to maintain, and particularly suitable for overall transformation of an existing old kiln.

The invention discloses a thermal power generating unit draught fan structure support overall transfer device and a transfer method. The overall transfer device is mainly composed of a lifting system, a rail system, a traction system and structure strengthening facilities. The transfer method specifically includes the following steps that: a steel structure support and equipment overall transfer scheme is designed; the scheme is checked, calculated, adjusted and optimized; the arrangement location of a hydraulic jack and the arrangement location of a transfer rail are determined; the ground at the rail is leveled, and a foundation is formed through pouring and is leveled; a steel plate is laid on the foundation; rail beams are arranged and welded, and a steel structure is strengthened; steel structure supporting equipment is strengthened; cable ropes are arranged; a vertical column and a column bottom plate are separated from each other; the hydraulic jack is arranged; overall jacking is performed; a heavy object conveying device is arranged; the jack is disassembled; overall horizontal movement is performed; integral jacking is performed; after the heavy object conveying device is dissembled, and the steel structure support is arranged in place; the vertical column is connected with the bottom plate; and temporary facilities are removed. According to the thermal power generating unit draught fan structure support overall transfer device and the transfer method of the invention, overall transfer construction technologies are adopted, and therefore, the quality of a project can be ensured, and safety risks can be reduced, and the construction period of the project can be shortened greatly.

The invention discloses a crude oil distillation method. A primary flash distillation tower is arranged between a normal pressure distillation tower and a pressure reduction furnace, a pressure reduction oil line from an outlet of the pressure reduction furnace to a pressure reduction distillation tower is omitted, a secondary flash distillation tower is arranged between the pressure reduction furnace and the pressure reduction distillation tower, tower bottom heavy oil of the normal pressure distillation tower, i.e. normal bottom oil enters the primary flash distillation tower after being mixed with cyclic pressure reduction slag oil, the tower top gas phase of the primary flash distillation tower is converted into a liquid phase to be used as products through heat exchange and condensing, bottom oil of the primary flash distillation tower enters the secondary flash distillation tower through being heated by the pressure reduction furnace, the tower top gas phase of the secondary flash distillation tower is converted into a liquid phase to be used as products through heat exchange and condensing, and bottom oil of the secondary flash distillation tower is introduced into a flash distillation section of the pressure reduction distillation tower for pressure reduction distillation. Compared with the prior art, the method has the advantages that on one hand, the yield of the pressure reduction slag oil is reduced, and the economic benefits of devices are improved; and on the other hand, the load of the pressure reduction furnace and the pressure reduction distillation tower is reduced, the device investment is saved, and the energy consumption of the devices is reduced.

The invention discloses a reduced pressure distillation method with low energy consumption and deep total distillation rate. By arranging a reduced pressure flashing tower behind a reduced pressure heating furnace, light fractions vaporized by heat are separated out, load of a reduced pressure distillation tower is reduced and energy consumption of an apparatus is reduced; by arranging a reduced pressure flashing tank behind the reduced pressure distillation tower, relatively light fractions in reduced pressure residues can be further flashed under a vacuum degree higher than that of the bottom of a reduced pressure distillation tower, yield of reduced pressure distillate oil is increased, and thus a reduced pressure distillation operation with low energy consumption and deep total drawing rate can be realized. With the reduced pressure distillation method, the content of fractions with a temperature lower than 500 DEG C in the reduced pressure residues can be reduced to the minimum, so that the distillation rate of the reduced pressure distillation is increased and economic benefits of the apparatus can be increased.

The invention relates to a hybrid direct current transmission topological system, including a rectification side converter station and an inversion side converter station connected with the rectification side converter station. The rectification side converter station comprises a rectification side converter transformer and a power grid commutation transverter. The inversion side converter station comprises a modular multi-level transverter and an inversion side commutation transverter, wherein the modular multi-level transverter adopts a full bridge submodule topology or a hybrid of the full bridge submodule topology and a half bridge submodule topology, and the inversion side commutation transverter is connected with the modular multi-level transverter. The hybrid direct current transmission topological system can replace an inversion side power grid commutation transverter with the modular multi-level transverter which adopts the full bridge submodule topology or the hybrid of the full bridge submodule topology and the half bridge submodule topology on the basis of a traditional direct current transmission system, and reconstructs the traditional direct current transmission system into a flexible direct current converter station, thereby forming a hybrid direct current topology. By means of reconstruction on the basis of the traditional direct current transmission system, traditional direct current transmission primary equipment at a reconstructed end can be fully utilized, the number of external purchasing equipment is reduced, the reconstruction period is shortened, and the cost is lowered.

The invention provides a reducing sizing mill with a short roller body, four upright posts and no house for bars. The reducing sizing mill consists of axial adjusting devices, upright posts, depressing devices, connecting rods, supporting seats, short roller body rollers, bearing blocks, roller shafts, taper sleeves, handles and roller rings. The reducing sizing mill is characterized by further comprising the short roller body rollers, wherein the ratio of the length to the diameter of the roller body of each roller is smaller than or equal to one second of the short roller; the short roller body roller is a combined roller; the reducing sizing mill is of a four-upright-post houseless structure; each depressing device is connected with the corresponding bearing block of each roller through the upright posts; the upright posts are fixed on the corresponding supporting seats; each short roller body roller is arranged in the corresponding bearing block through a bearing; each axial adjusting device is connected with the corresponding bearing block; each connecting rod is connected with the corresponding supporting seat; each supporting seat is fixed on a foundation base. The reducing sizing mill has the advantages that a four-upright-post houseless high-rigidity rolling mill is combined with the short roller bodies, so that the integral rigidity of the rolling mill can be improved, a jumping value of the roller under the same rolling force is reduced, and further the dimensional precision of rolled pieces is improved; the four-upright-post houseless high-rigidity rolling mill is combined with a low-temperature controlled rolling process, so that structure properties of the rolled pieces can also be improved.

The invention discloses a high-efficiency desulfurization absorption tower with control of empty tower partition pH values; the high-efficiency desulfurization absorption tower includes an absorption tower; the exterior of the absorption tower is provided with a high-pH-value slurry tank; the high-pH-value slurry tank and a low-pH-value slurry pool layer are connected by a valve pipeline, the high-pH-value slurry tank is provided with a limestone slurry supply pump; a high-pH-value region spray layer is arranged between a low-pH-value region spray layer and a mechanical demisting layer; the high-pH-value region spray layer and the high-pH-value slurry tank are connected by a high-pH-value circulation pipeline. Compared with the prior art, through arranging the high-pH-value slurry tank at the exterior of the absorption tower, the corresponding high-pH-value region spray layer is used for strengthening an absorption effect on SO2 in flue gas, slurry after the absorption effect is completed continues to strengthen oxidation of a neutralization reaction product calcium sulfite in the low-pH-value slurry pool layer in the absorption tower.

The invention provides a steel coil conveying system which comprises multiple sets of conveying roller way units, a plurality of steel coil saddles and lifting type transverse movement roller way vehicles. Each conveying roller way unit consists of a first heavy-load roller way and a first light-load roller way which are horizontally arranged, wherein the first heavy-load roller way is higher than the first light-load roller way; the plurality of steel coil saddles are conveyed by rollers of the conveying roller way units; and the lifting type transverse movement roller way vehicles are arranged at the feeding ends and the discharging ends of the conveying roller way units, the traveling direction of the lifting type transverse movement roller way vehicles is perpendicular to the distribution direction of the corresponding conveying roller way unit at present, and the tops of the lifting type transverse movement roller way vehicles are provided with lifting third light-load roller ways. The starting ends and the tail ends of the conveying roller way units are provided with the lifting type transverse roller way vehicles correspondingly, the steel coil saddle on the high-level roller way can be switched to the low-level roller way, and the steel coil saddle on the low-level roller way can be switched to the high-level roller way, so that the overall width of the conveying roller way units can be reduced.

The invention discloses a sectional feeding vacuum distillation method and an apparatus for crude oil. The method comprises the steps of omitting relatively long transfer line from the outlet of a vacuum furnace to the vacuum tower; arranging a flashing tower between the vacuum tower and a vacuum distillation tower; passing superheated steam through the bottom of the flashing tower; introducing the raw materials of vacuum distillation to the flashing tower through the vacuum furnace after being heated; educing relative light components (hereinafter referred to flashing top gas) in the flashing tower from the tower top after steam stripping evaporation; entering below a packing layer of some fractioning section of the vacuum distillation tower; and introducing the liquid phase (hereinafter referred to flashing bottom oil) educed from the bottom of the flashing tower to the feeding section of the vacuum distillation tower to perform vacuum distillation. The sectional feeding vacuum distillation method and the apparatus for the crude oil can obviously increase pull-out rate of the vacuum distillation process and improve the quality of the vacuum distillates.

The invention discloses a masonry structure transformation method and an underpinning structure for masonry structure transformation. The transformation method includes the steps that (10) constructional columns are reinforced, i.e., the constructional columns at the two ends of a wall to be demolished are reinforced with latticed columns, and the lower ends of the latticed columns are in tight contact with a foundation; (20) underpinning beams are arranged, steel box beams are arranged on the two sides of ring beams of the wall to be demolished, the two ends of each steel box beam are fixedly connected with the latticed columns at the two ends of the wall to be demolished correspondingly, and the side faces of the steel box beams are fixedly connected with the ring beams of the wall to be demolished; and (30) the masonry work wall is demolished, i.e., a wall body to be demolished under the ring beams is demolished. The underpinning structure comprises the latticed columns (1) and the steel box beams (2), the latticed columns are arranged around the constructional columns (4) at the two ends of the wall to be demolished (3) in a reinforcing mode, the steel box beams (2) are arranged on the two sides of the ring beams (5) of the wall to be demolished, the two ends of each steel box beam (2) are fixedly connected with the latticed columns (4) at the two ends of the wall to be demolished (3) correspondingly, and the side faces of the steel box beams (4) are fixedly connected with the ring beams (5) of the wall to be demolished. According to the masonry structure transformation method and the underpinning structure for masonry structure transformation, construction is simple, and investment is little.

The invention relates to the field of sewage treatment, and especially relates to an aeration pipe and a self-cleaning method. The aeration pipe comprises an outer membrane (102) and an aeration inner pipe (103); the outer membrane (102) is made of an elastic material, and a plurality of flow guide ports (101) are formed in the outer membrane (102); one end of the aeration inner pipe (103) is sealed, and the other end of the aeration inner pipe (103) is connected with an air supply pipeline of an aeration system; a plurality of aeration inner pipe side holes (104) are formed in the aeration inner pipe (103); and the outer membrane (102) sleeves the outer side of the aeration inner pipe (103). When large bubbles flow out of the side holes (104) of the aeration inner pipe and then are discharged through a flow guide port on the outer membrane (102), the pressure at the flow guide port is reduced, the outer membrane retracts by virtue of elasticity, and the gas is blocked again, reduced or interrupted; meanwhile, under the conveying action of a fan, the outer membrane of the flow guide port is opened again by the pressure of the air, a large amount of bubbles flow out, and continuous oscillation turbulence is formed.

The invention discloses a deep reduced pressure flash tank and a reduced pressure deep distillation method. The reduced pressure flash tank comprises a tank body and internal members of the tank. The internal members comprises a feeding inlet distributor arranged in a gas phase zone at the upper part of the reduced flash tank and a rotary disk arranged above a liquid surface of the lower part liquid phase zone, wherein the rotary disk is fixed on a rotary shaft arranged in an axis direction of the tank body. In the reduced pressure deep distillation method, the reduced pressure flash tank is arranged behind the reduced pressure tower; the atmospheric pressure bottom oil is heated by a reduced pressure furnace and introduced to the reduced pressure tower through a reduced pressure transfer line; reduced pressure light fraction oil is pumped out from the lateral line of the reduced pressure tower; reduced pressure heavy oil is pumped out from the bottom of the tower and introduced to the reduced pressure flash tank; the obtained gas phase is introduced to a gas-liquid separation tank; the reduced pressure light fraction oil is discharged from the bottom of the gas-liquid separation tank; and the flashed reduced pressure residual oil is discharged from the bottom of the reduced pressure flash tank. The deep reduced pressure flash tank and the reduced pressure deep distillation method can obviously increase distillation yield during a distillation process of crude oil, reduce energy consumption during the process and increase economic benefits of the apparatus.

The invention discloses a dry electric precipitator with a metal mesh anode plate. The dry electric precipitator comprises a shell, the anode plate and an corona line, the anode plate and the corona line are arranged in the shell, the anode plate and the corona line are arranged alternately and in parallel, and an electric field is formed between the anode plate and the corona line; and the anodeplate comprises a frame and a metal mesh, the metal mesh is fixed in the frame, and the void rate of the metal mesh is 8-20%. The dry electric precipitator has the advantages that through the metal mesh, the lateral scour force of the ion wind on the anode plate is weakened, the production of secondary raising dust is reduced, the pressure of the overall device is lowered below 250 Pa, the equipment resistance is reduced, the fan design requirements and operating energy consumption are reduced simultaneously, and the fact that the outlet particle concentration is below 10 mg / m3 can be achieved; and the current density is significantly reduced, the total current required for the whole anode plate is reduced, the energy saving effect is obvious, the weight of the anode plate is also reduced,the total weight of the whole electric precipitator is greatly reduced, the overall steel mass, installation, manufacture and the like of the electric precipitator are reduced, and the cost is greatly reduced.

The invention provides a wet desulfurization flue gas ultra-clean emission treatment system. The treatment system comprises: supercharging atomizing equipment, which is used for humidifying desulfurization flue gas to obtain humidified flue gas; purification equipment, which is connected to the supercharging atomizing equipment, and is used for purification of the humidified flue gas to realize gas-liquid-solid separation, thus obtaining clean flue gas and flue dust containing liquid water; and circulating water filtration equipment, which is connected to the purification equipment to filter flue dust containing liquid water so as to obtain filtered liquid water, which can be recycled by the supercharging atomizing equipment. While realizing flue gas purification, the wet desulfurization flue gas ultra-clean emission treatment system provided by the invention recycles moisture in the flue gas, has powerful water saving function, basically can achieve zero water replenishment, and saves cost.

The invention discloses a main return air duct reconstruction method suitable for concentrated return air in a downhole. The reconstruction method comprises the steps of S1, designing the reconstruction scheme of a main return duct; S2, driving a return air ramp in communication with a shallowest part middle stage return air stone door; S3, driving a new return air horse head door to communicate with a lower arc section and a return air well; S4, expanding the brush on a return air stone door between the upper opening of the return air ramp and a shallowest part middle stage return air horse head door; S5, arranging a platform used for sealing a rockshaft of the return air well; S6, driving a main fun chamber; S7, arranging a main fun in the main fun chamber; and S8, arranging a spraying device in a total return air duct at the exit of the main fan in the downhole to wash and purify polluted air. According to the reconstruction method, the problem of mutual interference caused by the parallel connection of a multi-middle stage return air stone door blower in the downhole under the condition of the absence of a centralized return blower station is solved effectively, the difficult problem that the main fan cannot be installed in the wellhead of the return air well due to land expropriation, environmental protection or geographical reasons can be solved, the reconstruction methodhas the little influence on an existing ventilation system, and environmental protection is achieved.

The invention discloses aluminum stone kiln bond breaking denitration equipment and a denitration method. The equipment includes an aluminum stone kiln. The upper and lower parts of the outer wall of the aluminum stone kiln are respectively connected to a flue and a fresh air pipeline. A flue gas reflux pipeline is connected to the flue. An air mixer is arranged at the intersection of the glue gas reflux pipeline and the fresh air pipeline. The end of the flue is connected to a desulfurization and denitration dust remover I, a trap and a desulfurization and denitration dust remover II. Sewage discharge ports of the desulfurization and denitration dust remover I and the desulfurization and denitration dust remover II communicate with a circulation tank. An air outlet of a desulfurization and dedusting reaction vessel communicates with a water-mist separator. An air-out pipeline of the water-mist separator is connected to a chimney. The equipment also includes an ammonia water storage tank and a nitrogen oxide bond breaker. A pipeline mixer is mounted on the upper end of the nitrogen oxide bond breaker. The pipeline mixer communicates with a flue gas high temperature region of the aluminum stone kiln through a mixed pipeline. The ammonia water storage tank communicates with the pipeline mixer through an ammonia supply pump to supply ammonia. The whole process is simple, the equipment reconstruction cost is low, and the denitration efficiency is high, which fully meets the environmental protection requirements.

The invention discloses a crude oil reduced pressure distillation method for eliminating a choke point in a pressure reduction process. The method comprises the following steps: firstly, performing heat exchange on atmospheric pressure residual oil through an atmospheric pressure furnace convection section and a reduced pressure furnace convection section, raising the temperature by 5-20 DEG C, then feeding the residual oil into a reduced pressure flash column, operating the reduced pressure flash column at 5-30kPa, at the same time, introducing reduced pressure flash column light lube oil as washing oil from the upper part of a reduced pressure distillation column, performing heat exchange on a gas on the top of the reduced pressure flash column, condensing, cooling and directly extracting the gas as a product, extracting the washing oil in the middle of the reduced pressure flash column, feeding the washing oil below a light lube oil extracting plate of the reduced pressure flash column, feeding the flash base oil of the reduced pressure flash column into a reduced pressure furnace, heating to be 370-410 DEG C, feeding into the reduced pressure distillation column through an oil transfer line, performing reduced pressure fractionation, and then extracting products of different fractions from a side line of the reduced pressure distillation column. The method improves the crude oil reduced pressure distillation process, eliminates the choke points of the reduced pressure furnace and the reduced pressure distillation column, reduces energy consumption, improves the treatment capacity and increases the economic benefits of a device.