CN101613617B

CN101613617B - Method for preparing biological oil through vacuum pyrolysis of biomasses

Info

Publication number: CN101613617B
Application number: CN2009101832292A
Authority: CN
Inventors: 肖国民; 刘楠; 王恋
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2009-07-23
Filing date: 2009-07-23
Publication date: 2012-07-04
Anticipated expiration: 2029-07-23
Also published as: CN101613617A

Abstract

The invention relates to a method for preparing biological oil through vacuum pyrolysis of biomasses, which comprises the following technological processes: (1) vacuum pyrolysis: adding raw materials after pretreatment into a reaction kettle, and heating a peripheral pipe type furnace to raise the temperature for pyrolysis, wherein a heat conducting device is arranged in the reaction kettle; (2) condensation: introducing volatile components (mainly comprising water vapor) at a low temperature into a drying tower, and guiding the volatile components at a high temperature into a coil condenser for condensation, wherein the online sampling can be achieved in the process of the pyrolysis; and (3) absorption: absorbing the water vapor in incondensable gas by the drying tower and absorbing nitride and sulfide by a bubbling absorption bottle so as to effectively reduce the pollution caused by vacuum pump oil. The method partially solves the problem of temperature rise hysteresis caused by the low heat transfer efficiency of the biomasses in the process of the temperature rise and the problem of low condensation efficiency and the online sampling, and simultaneously the method preliminarily reduces the water content in the biological oil.

Description

A kind of method of preparing biological oil through vacuum pyrolysis of biomasses

Technical field

The invention discloses a kind of recovery method of biomass solid waste, particularly a kind of under the certain vacuum degree pyrolysis produce the method for bio oil.

Background technology

Along with the scarcity day by day of fossil energy, biomass energy is enriched with its hypotoxicity, low pollution and reserves and is begun to receive publicity.

Biomass thermal chemical transformation technology is a kind of of Biomass Energy Utilization technology; Wherein vacuum cracking is to be the technology of major objective product with the liquid phase bio oil; This technology makes biomass material be converted under certain vacuum degree and temperature can not coagulate combustion gas, three kinds of energy forms of bio oil and coke.Biomass at high temperature at first change into fugitive constituent, and this fugitive constituent is converted into bio oil and can not coagulates combustion gas through behind the condensing works.The composition of fugitive constituent is similar to flue gas, and condensation method commonly used at present is that chilling coagulates.Patent CN101343547A discloses the method that bio oil is produced in a kind of vacuum cracking classification, but the condensing works limitation of design has restricted the productive rate of bio oil, and because whole system is in negative pressure condition, is difficult to realize the online sampling of sample.The condensation of the disclosed cracked oil condensation method of CN1030252A takes time one-level phlegma to the previous stage condensation, may cause the polymerization even the coking of lower boiling heat-sensitive substance.Contain a large amount of moisture in the bio oil of condensation, and miscible with the polar compound height among the bio oil, be difficult to separate.Conventional separation method is owing to the poor heat stability of bio oil is difficult to reach ideal effect, like underpressure distillation.Though method such as column chromatography and short-path distillation can well be isolated moisture, its cost is too high, only is applicable to the separation of produced of high added value product.Moisture in the bio oil is from two portions; A part comes from the free-water of biomass absorption itself; A part comes from the water that cracking produces, and biomass material can be removed free-water through after the drying treatment, but the moisture in still can absorbed air in the process of its transfer and sealing.In addition, in the cracked starting stage, owing to be in low-pressure state in the still, gas content is few, and biomass itself are the poor conductors of heat, so there is hysteresis quality in its heat transfer, thereby has increased the TRT of biomass.

Summary of the invention

Technical problem: the purpose of the method for the present invention is that provides a kind of method of preparing biological oil through vacuum pyrolysis of biomasses; Improve the condensation effect of fugitive constituent and realize the online sampling of sample; Can increase simultaneously the heat transfer efficiency in the reactor drum; Suitably reduce the content of moisture in the oil phase, partly solve the problem of cracked oil later separation difficulty.

Technical scheme: the method for preparing biological oil through vacuum pyrolysis of biomasses of the present invention is specific as follows:

1) earlier the intensifying heat transfer device is positioned in the reaction kettle, adds the biomass samples of handling well, good seal flange face again; Start vacuum pump, inspection system resistance to air loss, confirm that resistance to air loss is good after; Close first T-valve; Open nitrogen valve and charge into nitrogen, question response still internal pressure rises to normal pressure, closes nitrogen valve;

2) close second stopping valve, open first T-valve and switch to the 3rd branch road, emptying reaction gas reactor;

3) treat that system vacuum tightness reaches about 5-10kpa, start temperature controller, the control furnace temperature is warming up to 105-140 ℃ in the fs, under this temperature, stops 15-35 minute, removes free-water residual in the biomass;

4) first T-valve is cut to the 4th branch road, and second T-valve switches to first scoop, opens the 4th stopping valve, regulates the 5th stopping valve on the resorber, obtains suitable bubbling rate through the regulated valve switch size; Regulate temperature controller, the control furnace temperature rises to warm 400-600 ℃ eventually in subordinate phase with 10-30 ℃/min speed, and condensed product is collected in first scoop, second scoop, the 3rd scoop, and condensable gases is not compressed to be pumped in the collection and confinement of gases jar and collects;

5) during online sampling, close the 4th stopping valve, second T-valve switches to the 5th branch road, collection liquid sample from scoop; Open the 7th stopping valve and from the collection and confinement of gases jar, gather gaseous sample;

6) after question response finishes, close first T-valve, open the 6th stopping valve and prevent pump oil suck-back, close vacuum pump, close the 8th stopping valve, open nitrogen valve and charge into nitrogen, treat that the still internal pressure rises to normal pressure, closes nitrogen valve;

7) open first stopping valve, the 3rd stopping valve collection of biological oil, question response still temperature is reduced to room temperature, collects coke, the cleaning reactor drum.

Beneficial effect:

1, the inventive method can increase the heat transfer efficiency of reaction system, reduces the reaction times, reduces energy consumption, alleviates energy shortage to a certain extent;

2, the inventive method feeds nitrogen before and after reaction, effectively reduces the oxygen content of whole reaction system, has reduced the oxygen level of cracking component, has increased the product calorific value;

3, the inventive method adopts stainless steel elbow to immerse cooling medium, has increased contact area, has improved condensation effect, has increased the productive rate of pyrolysis oil;

4, the inventive method is provided with branch road L3 and L4 behind reaction kettle lead line L2, reduces the mixed volume of water vapor in bio oil under the low temperature in the switching through branch road under low temperature and the high temperature;

5, the inventive method can realize the online sampling of sample and not influence the vacuum tightness of whole reaction system;

6, the inventive method is equipped with absorption bottle before vacuum pump, can regulate the bubbling degree and improve assimilated efficiency through regulating intake valve, effectively reduces nitride and sulfide in the uncooled gas simultaneously to the oily pollution of pump.

Description of drawings

Fig. 1 is the inventive method apparatus structure synoptic diagram;

Fig. 2 is the bottom schematic view of intensifying heat transfer device in the inventive method device;

Fig. 3 is an intensifying heat transfer device sectional view in the inventive method device;

Fig. 4 is a heating curve.

Have among the above figure: 1, nitrogengas cylinder, 2, nitrogen valve, 3, reaction kettle, 4, tube furnace, 5, blind pipe, 6, thermopair; 7, vacuum meter, 8, first T-valve, 9, coil condenser, 10, second T-valve, 11, first stopping valve, 12, second stopping valve; 13, the 3rd stopping valve, the 14, the 4th stopping valve, the 15, the 3rd scoop, the 16, the 5th stopping valve, 17, resorber, 18, drying tower; 19, the 6th stopping valve, 20, vacuum pump, 21, surge flask, 22, compression pump, the 23, the 7th stopping valve; 24, collection and confinement of gases jar, the 25, the 8th stopping valve, 26, temperature controller, 27, first scoop, 28, second scoop; L1, first branch road, L2, second branch road, L3, the 3rd branch road, L4, the 4th branch road, L5, the 5th branch road.

Embodiment

Below in conjunction with accompanying drawing the inventive method is further described.

Embodiment:

As shown in Figure 1, the setting drawing of this inventive method comprises interconnective reactive system, condenser system and pump system.Reactive system comprises stainless steel cauldron 3, tube furnace 4 and temperature controller 26; The reaction kettle upper flange surface has interface, connects vacuum meter 7, blind pipe 5, the first branch road L1 and the second branch road L2 respectively, and the reaction kettle condenser system comprises three grades of condensations; Be equipped with water and mixture of ice and water respectively in the preceding condensed in two stages groove; Condensate trap and stainless steel elbow are welded as a whole 9, and the stainless steel elbow exit is connected to scoop, are salt ice in the third stage condensate trap.Pump system comprises resorber 17, drying tower 18, surge flask 21, vacuum pump 20, compression pump 22.The pipe fitting junction is respectively equipped with T-valve and stopping valve.

Comprehensive said apparatus, the step that bio oil is produced in the pyrolysis of this instance biomass vacuum is following:

With the wheat straw stalk is raw material, is crushed to particle size range 3-5mm, dries by the fire 12h down at 80-105 ℃.With heat-transfer device---be welded with the circular steel plate (like accompanying drawing 2, shown in 3) of heat conductive rod, place in the reaction kettle, then add raw material, the good seal flange face.Start vacuum pump 20, inspection system resistance to air loss, confirm that resistance to air loss is good after, close first T-valve 8, open nitrogen valve 2 and charge into nitrogen, question response still internal pressure rises to normal pressure, closes nitrogen valve 2.Close second stopping valve 12, open first T-valve 8 and switch to the 3rd branch road L3, emptying reaction gas reactor.The system vacuum tightness of treating reaches 5-10kpa, starts temperature controller 26, and the control furnace temperature is warming up to 105-140 ℃ in the fs, under this temperature, stops 10-30 minute, removes free-water residual in the biomass.First T-valve 8 is cut to the 4th branch road L4, and second T-valve 10 switches to first scoop 27, opens the 4th stopping valve 14, regulates the 5th stopping valve 16 on the resorber 17, obtains suitable bubbling rate through the regulated valve switch size.Regulate temperature controller 26; The control furnace temperature rises to warm 400-600 ℃ eventually in subordinate phase with 10-30 ℃/min speed; Condensed product is collected in first scoop 27, second scoop 28, the 3rd scoop 15, and condensable gases is not compressed pump 22 and is pressed in the collection and confinement of gases jar 24 and collects.During online sampling, close the 4th stopping valve 14, the second T-valve 10 and switch to the 5th branch road L5, collection liquid sample from scoop 11.Open the 7th stopping valve 23 and from collection and confinement of gases jar 24, gather gaseous sample; Question response is closed first T-valve 8 after finishing, and opens the 6th stopping valve 19 and prevents pump oil suck-back, closes vacuum pump 20, closes the 8th stopping valve 25, opens nitrogen valve 2 and charges into nitrogen, treats that the still internal pressure rises to normal pressure, closes nitrogen valve 2.Open first stopping valve, 11, the three stopping valve, 13 collection of biological oil, question response still temperature is reduced to room temperature, collects coke, the cleaning reactor drum.

Shown in Figure 4 is heating curve figure, and furnace temperature is risen to 500 ℃ by room temperature, and

curve

1,2,3 is respectively body of heater, adds heat-transfer device and does not add the heating curve in the heat-transfer device reaction kettle.Heat-transfer device has improved the hysteresis quality that biomass heat up, thereby can reduce the TRT, save energy.

Table 1 is the experiment correlation data, and data 1 be the normal straight tube condensation, and splitting gas directly gets into condenser system, passes through that step 3 low temperature does not dewater described in the inventive method; Data 2 are the said coil pipe condensation of the inventive method, through the low temperature step that dewaters.

Table 1 bio oil yield and water cut

Claims

1. the method for a preparing biological oil through vacuum pyrolysis of biomasses is characterized in that this method comprises the steps:

1) earlier the intensifying heat transfer device is positioned in the reaction kettle (3), adds the biomass samples of handling well, good seal flange face again; Start vacuum pump (20), inspection system resistance to air loss, confirm that resistance to air loss is good after; Close first T-valve (8); Open nitrogen valve (2) and charge into nitrogen, question response still internal pressure rises to normal pressure, closes nitrogen valve (2);

2) close second stopping valve (12), open first T-valve (8) and switch to the 3rd branch road (L3), emptying reaction gas reactor;

3) treat that system vacuum tightness reaches about 5-10kPa, start temperature controller (26), the control furnace temperature is warming up to 105-140 ℃ in the fs, under this temperature, stops 15-35 minute, removes free-water residual in the biomass;

4) first T-valve (8) is cut to the 4th branch road (L4), and second T-valve (10) switches to first scoop (27), opens the 4th stopping valve (14), regulates the 5th stopping valve (16) on the resorber (17), obtains suitable bubbling rate through the regulated valve switch size; Regulate temperature controller (26); The control furnace temperature rises to warm 400-600 ℃ eventually in subordinate phase with 10-30 ℃/min speed; Condensed product is collected in first scoop (27), second scoop (28), the 3rd scoop (15), and condensable gases is not compressed pump (22) and is pressed into collection in the collection and confinement of gases jar (24);

5) during online sampling, close the 4th stopping valve (14), second T-valve (10) switches to the 5th branch road (L5), collection liquid sample from scoop; Open the 7th stopping valve (23) and from collection and confinement of gases jar (24), gather gaseous sample;

6) after question response finishes, close first T-valve (8), open the 6th stopping valve (19) and prevent pump oil suck-back, close vacuum pump (20), close the 8th stopping valve (25), open nitrogen valve (2) and charge into nitrogen, treat that the still internal pressure rises to normal pressure, close nitrogen valve (2);

7) open first stopping valve (11), the 3rd stopping valve (13) collection of biological oil, question response still temperature is reduced to room temperature, collects coke, the cleaning reactor drum.