Method and system for preparing synthesis gas and hydrogen through organic waste steam pyrolysis gasification

Abstract

The invention discloses a method and system for preparing synthesis gas and hydrogen through organic waste steam pyrolysis gasification, and belongs to the field of organic waste treatment.The system comprises a reaction furnace, a regenerative heat exchanger, a washing tower, a purification and separation device, a flash tower and a steam high-temperature heating tower, and the reaction furnace is communicated with the regenerative heat exchanger through a first inlet; a first outlet of the backheating heat exchanger is communicated with a third inlet of the washing tower, and a third outlet of the washing tower is communicated with the purification and separation device; the purification and separation device outputs hydrogen and CO; a fourth outlet of the washing tower is communicated with a fifth inlet of the flash tower, and a fifth outlet of the flash tower is communicated with a fourth inlet of the washing tower; the flash tower is communicated with a second inlet of the backheating heat exchanger, a second outlet of the backheating heat exchanger is communicated with the steam high-temperature heating tower, and the steam high-temperature heating tower is communicated with the reaction furnace. Water vapor latent heat circulation and regenerative circulation are adopted, and the energy-saving effect is remarkable; the H2 / CO molar ratio of the produced gas is adjusted by adjusting the water vapor amount and the oxygen amount.

Description

Technical Field

[0001] This invention belongs to the field of organic waste treatment, and particularly relates to a method and system for producing syngas and hydrogen by steam pyrolysis and gasification of organic waste. Background Technology

[0002] Organic waste is rich in biomass resources. If not treated promptly and properly, it is prone to decay and odor, negatively impacting the surrounding environment. Combustion of organic waste increases carbon dioxide emissions, exacerbating the greenhouse effect; lipids, under the catalysis of heavy metals, can also produce dioxins. Landfilling organic waste generates large amounts of biogas and leachate, causing secondary soil pollution. China generates over 6 billion tons of various types of organic waste annually, equivalent to 1.6 billion tons of standard coal. Biomass has a high hydrogen content; producing hydrogen while treating organic waste is an environmentally friendly and economically viable method. Therefore, those skilled in the art propose a method and system for producing syngas and hydrogen through steam pyrolysis and gasification of organic waste. Summary of the Invention

[0003] In view of this, the present invention provides a method and system for producing syngas and hydrogen by steam pyrolysis and gasification of organic waste, in order to solve the above-mentioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A system for producing syngas and hydrogen from organic waste through steam pyrolysis and gasification includes: a reactor, a regenerating heat exchanger, a scrubbing tower, a purification and separation device, a flash evaporator, and a high-temperature steam heating tower. The regenerating heat exchanger has a first inlet, a second inlet, a first outlet, and a second outlet. The top of the reactor is connected to the regenerating heat exchanger through the first inlet. The scrubbing tower has a third inlet on its side wall and a third outlet at its top. The first outlet of the regenerating heat exchanger is connected to the third inlet of the scrubbing tower, and the third outlet of the scrubbing tower is connected to the purification and separation device. The purification and separation device is capable of outputting hydrogen and CO. The washing tower has a fourth outlet at its bottom and a fourth inlet on its side wall. The flash evaporator has a fifth outlet at its bottom and a fifth inlet on its side wall. The fourth outlet of the washing tower is connected to the fifth inlet of the flash evaporator, and the fifth outlet of the flash evaporator is connected to the fourth inlet of the washing tower. The top of the flash tower is connected to the second inlet of the regenerating heat exchanger, the second outlet of the regenerating heat exchanger is connected to the high-temperature steam heating tower, and the high-temperature steam heating tower is connected to the bottom of the reactor.

[0005] Furthermore, an oxygen supply pipe is connected to the bottom of the steam high-temperature heating tower and the reactor via a three-way valve.

[0006] Furthermore, it also includes a water-cooled condenser, which is installed on the connecting pipeline between the third outlet of the washing tower and the purification and separation device; the water-cooled condenser is provided with a sixth inlet and a sixth outlet, the sixth inlet is connected to a cold water source, the side wall of the washing tower is provided with a seventh inlet, and the sixth outlet of the water-cooled condenser is connected to the seventh inlet of the washing tower.

[0007] Furthermore, it also includes multiple steam compressors, which are respectively installed on the connecting pipeline between the water-cooled condenser and the purification and separation device, and on the connecting pipeline between the flash tower and the second inlet.

[0008] Furthermore, the reactor is equipped with a feeding auger at the top and a discharging auger at the bottom. The feeding auger is arranged vertically and the discharging auger is arranged horizontally.

[0009] A method for producing syngas and hydrogen by steam pyrolysis and gasification of organic waste, characterized by comprising the following steps: S1. Heated steam and oxygen are introduced into the reactor together. Biomass in organic waste enters the reactor through the top feeding auger device. Circulating balls are placed in the pyrolysis furnace. The circulating balls are made of nickel-based metal balls or dolomite. Steam and oxygen catalytically pyrolyze in an environment of 950℃-1200℃. S2. The pyrolysis gas enters the regenerating heat exchanger from the top of the reactor through the first inlet to cool down to 150°C. The cooled pyrolysis gas enters the scrubbing tower from the first outlet of the regenerating heat exchanger through the third inlet for scrubbing. The temperature of the scrubbed gas drops to 95°C. The scrubbed gas enters the water-cooled condenser from the third outlet of the scrubbing tower for further cooling and dehydration, and then enters the purification and separation unit to separate hydrogen and CO. S3. The cold water source enters the water-cooled condenser from the sixth inlet to exchange heat with the washed pyrolysis gas, recover the waste heat in the pyrolysis gas, and then enters the washing tower from the sixth outlet of the water-cooled condenser through the seventh inlet to replenish the washing tower. S4. Water in the washing tower enters the flash tower through the fourth outlet and the fifth inlet, where it is converted into water vapor through flash evaporation at an ambient temperature of 85°C. The water vapor then enters the regenerating heat exchanger through the second inlet at the top of the flash tower, where it exchanges heat with the pyrolysis gas flowing out of the reactor, raising the temperature of the water vapor to 900°C. The heated water vapor then enters the high-temperature steam heating tower through the second outlet of the regenerating heat exchanger, further heating the water vapor to 1200°C. The heated water vapor is then fed into the reactor along with oxygen.

[0010] Furthermore, in step S4, the water at the bottom of the flash tower re-enters the washing tower through the fifth outlet and the fourth inlet, thereby realizing the circulating washing and flash evaporation between the washing tower and the flash tower.

[0011] The beneficial effects of this invention are as follows: In this invention, heated water vapor and oxygen are introduced into a reactor together. After reacting in the reactor, pyrolysis gas is generated. The pyrolysis gas is then cooled by a regenerative heat exchanger, purified by a scrubbing tower, cooled and dehydrated by a water-cooled condenser, and finally enters a purification and separation device to separate the product gas through pressure swing adsorption. Cold water enters the washing tower through a water-cooled condenser. While replenishing water, it can also absorb residual heat from the pyrolysis gas after washing through heat exchange. The water in the washing tower enters the flash evaporation tower for flash evaporation and pressurization (saturation temperature and pressure 105℃) into water vapor. When the water vapor passes through the regenerating heat exchanger, it is heated to 900 degrees with the pyrolysis gas, and then enters the high-temperature steam heating tower for further heating to 1200 degrees. Finally, it enters the reactor together with oxygen to carry out the pyrolysis reaction. During the process, the washing tower and the flash evaporation tower can achieve cyclic washing and flash evaporation.

[0012] This invention employs a latent heat cycle and a regenerative cycle of steam, resulting in significant energy savings. Steam is pyrolyzed at atmospheric pressure, and the H2 / CO molar ratio of the produced gas is adjusted by regulating the amount of steam and oxygen. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of a system for producing syngas and hydrogen through steam pyrolysis and gasification of organic waste.

[0015] In the figure: 1-Reactor, 2-Regenerative heat exchanger, 3-Scrubbing tower, 4-Purification and separation device, 5-Flash tower, 6-High-temperature steam heating tower, 7-First inlet, 8-Second inlet, 9-First outlet, 10-Second outlet, 11-Third inlet, 12-Third outlet, 13-Fourth outlet, 14-Fourth inlet, 15-Fifth outlet, 16-Fifth inlet, 17-Oxygen supply pipe, 18-Water-cooled condenser, 19-Sixth inlet, 20-Sixth outlet, 21-Seventh inlet, 22-Steam compressor, 23-Feeding auger device, 24-Discharge auger device. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1

[0018] See attached document Figure 1 As shown, this invention provides a system for producing syngas and hydrogen through steam pyrolysis and gasification of organic waste, comprising: a reactor 1, a regenerating heat exchanger 2, a scrubbing tower 3, a purification and separation device 4, a flash evaporator 5, and a high-temperature steam heating tower 6. The regenerating heat exchanger 2 is provided with a first inlet 7, a second inlet 8, a first outlet 9, and a second outlet 10. The top of the reactor 1 is connected to the regenerating heat exchanger 2 through the first inlet 7. The side wall of the scrubbing tower 3 is provided with a third inlet 11, and the top is provided with a third outlet 12. The first outlet 9 of the regenerating heat exchanger 2 is connected to the third inlet 11 of the scrubbing tower 3, and the third outlet 12 of the scrubbing tower 3 is connected to the purification and separation device 4. The purification and separation device 4 is capable of outputting hydrogen and CO. The washing tower 3 has a fourth outlet 13 at its bottom and a fourth inlet 14 on its side wall. The flash tower 5 has a fifth outlet 15 at its bottom and a fifth inlet 16 on its side wall. The fourth outlet 13 of the washing tower 3 is connected to the fifth inlet 16 of the flash tower 5, and the fifth outlet 15 of the flash tower 5 is connected to the fourth inlet 14 of the washing tower 3. The top of the flash tower 5 is connected to the second inlet 8 of the regenerating heat exchanger 2, the second outlet 10 of the regenerating heat exchanger 2 is connected to the high-temperature steam heating tower 6, and the high-temperature steam heating tower 6 is connected to the bottom of the reactor 1.

[0019] In a preferred embodiment, the high-temperature steam heating tower 6 and the bottom of the reactor 1 are connected by a three-way valve to an oxygen supply pipe 17, which provides oxygen supply according to the site conditions during system operation.

[0020] In a preferred embodiment, an organic waste steam pyrolysis gasification system for producing syngas and hydrogen further includes a water-cooled condenser 18, which is installed on the connecting pipeline between the third outlet 12 of the scrubbing tower 3 and the purification and separation device 4. The water-cooled condenser 18 is provided with a sixth inlet 19 and a sixth outlet 20. The sixth inlet 19 is connected to a cold water source, and a seventh inlet 21 is provided on the side wall of the scrubbing tower 3. The sixth outlet 20 of the water-cooled condenser 18 is connected to the seventh inlet 21 of the scrubbing tower 3.

[0021] An organic waste steam pyrolysis gasification system for producing syngas and hydrogen also includes multiple steam compressors 22, which are respectively installed on the connecting pipeline between the water-cooled condenser 18 and the purification and separation device 4, and on the connecting pipeline between the flash tower 5 and the second inlet 8.

[0022] In a preferred embodiment, a feeding auger device 23 is provided at the top of the reactor 1, and a discharging auger device 24 is provided at the bottom. The feeding auger device 23 is arranged vertically, and the discharging auger device 24 is arranged horizontally. Organic waste is fed into the reactor 1 from the top through the feeding auger device 23 for pyrolysis. The waste after pyrolysis is mainly pyrolytic carbon, which is discharged from the bottom of the reactor 1 and transported by the discharging auger device 24, and then bagged and collected at the output end of the discharging auger device 24.

[0023] Example 2

[0024] A method for producing syngas and hydrogen by steam pyrolysis and gasification of organic waste includes the following steps: S1. Heated steam and oxygen are introduced into reactor 1 together. Biomass in organic waste enters reactor 1 through feeding auger device 23 at the top. Circulating balls are placed in the pyrolysis furnace. The circulating balls are made of nickel-based metal balls or dolomite. Steam and oxygen are catalytically pyrolyzed in an environment of 950℃-1200℃. S2. The pyrolysis gas enters the regenerating heat exchanger 2 from the top of the reactor 1 through the first inlet 7 to cool down to 150°C. The cooled pyrolysis gas enters the washing tower 3 from the first outlet 9 of the regenerating heat exchanger 2 through the third inlet 11 for washing. The temperature of the washed gas drops to 95°C. The washed gas enters the water-cooled condenser 18 from the third outlet 12 of the washing tower 3 for further cooling and dehydration, and then enters the purification and separation device 4 to separate hydrogen and CO. S3. Cold water enters the water-cooled condenser 18 from the sixth inlet 19 to exchange heat with the washed pyrolysis gas, recover the waste heat in the pyrolysis gas, and then enters the washing tower 3 from the sixth outlet 20 of the water-cooled condenser 18 through the seventh inlet 21 to replenish the washing tower 3. S4. Water in the washing tower 3 enters the flash tower 5 through the fourth outlet 13 and the fifth inlet 16. In the flash tower 5, water vapor is generated by flash evaporation at an ambient temperature of 85°C. The water vapor enters the regenerating heat exchanger 2 through the second inlet 8 from the top of the flash tower 5 and exchanges heat with the pyrolysis gas flowing out of the reactor 1, raising the temperature of the water vapor to 900°C. The heated water vapor enters the high-temperature steam heating tower 6 through the second outlet 10 of the regenerating heat exchanger 2, further heating the water vapor to 1200°C. The heated water vapor is then fed into the reactor 1 along with oxygen. Water at the bottom of the flash tower 5 re-enters the washing tower 3 through the fifth outlet 15 and the fourth inlet 14, thus achieving a cycle of washing and flash evaporation between the washing tower 3 and the flash tower 5.

[0025] The above descriptions are merely specific embodiments of the present invention, and common knowledge regarding the specific structures and characteristics of the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

[0026] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0027] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for producing syngas and hydrogen through steam pyrolysis and gasification of organic waste, characterized in that, include: The reactor (1), regenerating heat exchanger (2), scrubbing tower (3), purification and separation device (4), flash evaporator (5), and high-temperature steam heating tower (6) are provided. The regenerating heat exchanger (2) is provided with a first inlet (7), a second inlet (8), a first outlet (9), and a second outlet (10). The top of the reactor (1) is connected to the regenerating heat exchanger (2) through the first inlet (7). The side wall of the scrubbing tower (3) is provided with a third inlet (11), and the top is provided with a third outlet (12). The first outlet (9) of the regenerating heat exchanger (2) is connected to the third inlet (11) of the scrubbing tower (3), and the third outlet (12) of the scrubbing tower (3) is connected to the purification and separation device (4). The purification and separation device (4) can output hydrogen and CO. The washing tower (3) has a fourth outlet (13) at its bottom and a fourth inlet (14) on its side wall. The flash tower (5) has a fifth outlet (15) at its bottom and a fifth inlet (16) on its side wall. The fourth outlet (13) of the washing tower (3) is connected to the fifth inlet (16) of the flash tower (5), and the fifth outlet (15) of the flash tower (5) is connected to the fourth inlet (14) of the washing tower (3). The top of the flash tower (5) is connected to the second inlet (8) of the regenerating heat exchanger (2), the second outlet (10) of the regenerating heat exchanger (2) is connected to the high-temperature steam heating tower (6), and the high-temperature steam heating tower (6) is connected to the bottom of the reactor (1).

2. The system for producing syngas and hydrogen from organic waste through steam pyrolysis gasification according to claim 1, characterized in that, The steam high-temperature heating tower (6) and the bottom of the reactor (1) are connected by a three-way valve to an oxygen supply pipe (17).

3. The system for producing syngas and hydrogen from organic waste through steam pyrolysis gasification according to claim 1, characterized in that, It also includes a water-cooled condenser (18), which is installed on the connecting pipeline between the third outlet (12) of the washing tower (3) and the purification and separation device (4); the water-cooled condenser (18) is provided with a sixth inlet (19) and a sixth outlet (20), the sixth inlet (19) is connected to a cold water source, the side wall of the washing tower (3) is provided with a seventh inlet (21), and the sixth outlet (20) of the water-cooled condenser (18) is connected to the seventh inlet (21) of the washing tower (3).

4. The system for producing syngas and hydrogen from organic waste through steam pyrolysis gasification according to claim 3, characterized in that, It also includes multiple steam compressors (22), which are respectively installed on the connecting pipeline between the water-cooled condenser (18) and the purification and separation device (4), and on the connecting pipeline between the flash tower (5) and the second inlet (8).

5. The system for producing syngas and hydrogen from organic waste through steam pyrolysis gasification according to claim 1, characterized in that, The reactor (1) is equipped with a feeding auger device (23) at the top and a discharging auger device (24) at the bottom. The feeding auger device (23) is arranged vertically and the discharging auger device (24) is arranged horizontally.

6. A method for producing syngas and hydrogen by steam pyrolysis and gasification of organic waste, characterized in that, Includes the following steps: S1. Heated steam and oxygen are introduced into the reactor (1). Biomass in organic waste enters the reactor (1) through the top feeding auger device (23). A circulating ball is placed in the pyrolysis furnace. The circulating ball is made of nickel-based metal or dolomite. Steam and oxygen are catalytically pyrolyzed in an environment of 950℃-1200℃. S2. The pyrolysis gas enters the regenerating heat exchanger (2) from the top of the reactor (1) through the first inlet (7) to cool down, and the temperature of the pyrolysis gas drops to 150°C. The cooled pyrolysis gas enters the scrubbing tower (3) through the third inlet (11) from the first outlet (9) of the regenerating heat exchanger (2) for scrubbing, and the temperature of the scrubbing gas drops to 95°C. The scrubbing gas enters the water-cooled condenser (18) from the third outlet (12) of the scrubbing tower (3) for further cooling and dehydration, and then enters the purification and separation device (4) to separate hydrogen and CO. S3. The cold water source enters the water-cooled condenser (18) from the sixth inlet (19) to exchange heat with the washed pyrolysis gas, recover the residual heat in the pyrolysis gas, and then enters the washing tower (3) from the sixth outlet (20) of the water-cooled condenser (18) through the seventh inlet (21) to replenish the washing tower (3); S4. Water in the washing tower (3) enters the flash tower (5) through the fourth outlet (13) and the fifth inlet (16). Water vapor is generated in the flash tower (5) through flash evaporation. The flash evaporation environment temperature is 85°C. Water vapor enters the regenerating heat exchanger (2) through the second inlet (8) from the top of the flash tower (5) and exchanges heat with the pyrolysis gas flowing out from the reactor (1). The temperature of the water vapor is heated to 900°C. The heated water vapor enters the high-temperature steam heating tower (6) through the second outlet (10) of the regenerating heat exchanger (2) to further heat the temperature of the water vapor to 1200°C. The heated water vapor is introduced into the reactor (1) together with oxygen.

7. The method for producing syngas and hydrogen by steam pyrolysis gasification of organic waste according to claim 6, characterized in that, In step S4, the water at the bottom of the flash tower (5) re-enters the washing tower (3) through the fifth outlet (15) and the fourth inlet (14), thereby realizing the circulating washing and flash evaporation between the washing tower (3) and the flash tower (5).

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