WO2013127159A1

WO2013127159A1 - Heat-accumulating type biomass pyrolysis method and system therefor

Info

Publication number: WO2013127159A1
Application number: PCT/CN2012/080271
Authority: WO
Inventors: 吴道洪; 肖磊; 刘静雅
Original assignee: 北京神雾环境能源科技集团股份有限公司
Priority date: 2012-02-28
Filing date: 2012-08-16
Publication date: 2013-09-06

Abstract

Provided is a heat-accumulating type biomass pyrolysis method comprising following steps: (1) biomass pre-treatment; (2) biomass pyrolysis: the biomass raw materials treated in step (1) are pyrolyzed in a heat-accumulating type gas radiant tube rotating bed to generate gaseous substances and solid biochar; and (3) collection and post-treatment of the pyrolysis product: gaseous substances generated in step (2) are collected to separate pyrolysis gas and condensable liquid through condensation, and all or part of the pyrolysis gas is used as the fuel for the heat-accumulating type gas radiant tube; and the discharged solid biochar is collected after coke quenching and cooling. Also provided is a heat-accumulating type biomass pyrolysis system. The system comprises a heat-accumulating type gas radiant tube rotating bed (1), a biomass pre-treatment system (2) connected with the feed port of the heat-accumulating type gas radiant tube rotating bed (1), a coke quenching and cooling device (3) connected with the solid substance outlet of the heat-accumulating type gas radiant tube rotating bed (1), a condensing device (4) connected with the gaseous substance outlet of the heat-accumulating type gas radiant tube rotating bed (1), and a pre-heating device(5) connected with the fuel gas inlet of the heat-accumulating type gas radiant tube rotating bed (1). The pyrolysis gas outlet of the condensing device (4) is connected with a purifier (6). The purified gas outlet of the purifier (6) is connected with the fuel gas inlet of the preheating device (5), and the pre-heating device (5) is also provided with an air inlet.

Description

Description A regenerative biomass pyrolysis method and system thereof

Technical field

The present invention relates to a biomass pyrolysis method and system thereof, and more particularly to a regenerative biomass pyrolysis method and system therefor. Background technique

As people's demand for energy grows, the fuel as the main source of energy is rapidly decreasing. According to the US Department of Energy and the World Energy Council, the global mining years of fuel coal, oil and natural gas are 211, 39 and 60 years respectively. And the use of large quantities of fossil fuels has led to global warming and increased SOx and NOx emissions, which have seriously polluted the atmosphere. Therefore, the search for a renewable and environmentally friendly energy source has become the focus of widespread concern in society. Among the various renewable energy sources, biomass is unique in that it not only stores solar energy, but also a renewable carbon source that can be converted into conventional solid, liquid and gaseous fuels. The efficient use of biomass energy can not only reduce The amount of fossil fuel used can also suppress carbon dioxide emissions. It is estimated that plants on Earth use 2xlO ^u tons of carbon per year through photosynthesis, with energy up to 3xl0 ¹⁸ kJ, and the energy that can be developed is about 10 times the annual energy consumption of the world. China's biomass energy resources are quite abundant. The theoretical biomass energy resources are about 5x10 ⁹ tons of standard coal, which is four times the total energy consumption in China. Biomass efficient use of technology began in the late 1970s, using thermochemical conversion and biotransformation technologies to convert biomass into gas, liquid and solid energy products and chemicals. Thermochemical methods include: direct combustion, gasification and pyrolysis. Numerous studies have found that biomass pyrolysis technology is an important approach to biomass utilization, especially with the increasing research on pyrolysis products, the research of pyrolysis technology for the purpose of obtaining the largest amount of liquid products (bio-oil). Applications are getting more and more attention. Biomass pyrolysis is a biomass pyrolysis process in which biomass (bio-oil), gas (combustible gas), solid (biochar) are produced under a certain gasification medium. The conversion of biomass pyrolysis and liquefaction into biofuels is an inevitable direction for the development of biomass pyrolysis technology. In the future, this technology will be widely developed and applied, and will produce huge social and economic benefits.

Existing biomass pyrolysis technologies mainly include fixed bed biomass pyrolysis and fluidized bed biomass pyrolysis technology. Fixed bed biomass pyrolysis has problems in that the material layer is unevenly heated and cannot be continuously operated. However, the internal temperature of the bed can be made uniform, but the treatment scale is small, the material particles are required to be small, and the pyrolysis gas and the fluidized gas are mixed together, thereby increasing the separation process of the pyrolysis gas and the fluidized gas. In addition, the conventional external heating method requires a large amount of gas to be consumed, and the running cost is high. Other technologies under development include vacuum moving bed, drainage bed, entrained flow, multi-furnace device, rotating cone and other biomass pyrolysis technologies. The common disadvantages are smaller processing scale and higher energy consumption. Summary of the invention

The invention provides a regenerative biomass pyrolysis method and system capable of mass production, low operating cost and low total energy consumption.

A regenerative biomass pyrolysis method that achieves one of the objects of the present invention includes the following steps:

(1) Pretreatment of biomass, which can be used as a raw material for biomass pyrolysis after pretreatment of biomass feedstock;

(2) Biomass pyrolysis, the biomass raw material treated in step (1) is evenly spread on the bottom of the regenerative gas radiant tube rotating bed, and the raw material is gradually dispersed in the confined space as the bottom of the furnace rotates. Heating, staying at a reaction temperature of 200-800 ° C for 30-120 minutes to form a gaseous substance and solid biochar; the heat in the rotating bed is provided by a regenerative gas radiant tube arranged in a rotating bed, the smoke inside the radiant tube The gas is isolated from the gaseous matter in the rotating bed;

(3) collecting and post-treating the pyrolysis product, collecting the gaseous matter produced in the step (2), separating the pyrolysis gas and the condensable liquid by condensation, and the pyrolysis gas is used as the fuel of the regenerative gas radiant tube. The condensable liquid is separated by oil and water to obtain bio-oil; the discharged solid biochar is collected after quenching and cooling.

The pyrolysis gas in the step (3) is stored in the gas tank after purification (decoking, desulfurization, denitration); the pyrolysis gas in the gas tank is connected to the regenerative burner through a pressure device and a pipe. As the gas, the gas source is provided for the regenerative burner; there is also a supplemental combustion gas circuit to provide supplemental combustion gas when the pyrolysis gas is insufficient or unstable.

The preprocessing of the step (1) includes one or more of the following:

Biomass drying;

Biomass crushing;

The biomass is granulated or lumpy, and after pulverization, the biomass is compressed into a granule, a block or a cylinder.

In the step (2), the thickness of the layer of the biomass laid at the bottom of the furnace is 50 to 400 mm. The gaseous matter produced in the step (2) is collected through a pipeline at the top or side wall of the rotating bed, and the solid biochar is discharged through the sealed discharge machine after rotating in the furnace for one week with the bottom of the furnace.

The condensable liquid separated in the step (3) is separated by oil and water to obtain bio-oil and sewage. The gaseous substance in the step (3) may be contacted with a catalyst before condensation to carry out a catalytic conversion reaction of hydrocarbon upgrading.

A regenerative biomass pyrolysis system that achieves the second object of the present invention includes a regenerative gas radiant tube rotating bed, a biomass pretreatment system connected to a feed port of the regenerative gas radiant tube rotating bed, a quenching cooling device connected to a solid matter outlet of the regenerative gas radiant tube rotating bed, a condensing device connected to a gaseous substance outlet of the regenerative gas radiant tube rotating bed, and the regenerative gas radiation a preheating device connected to the gas inlet of the rotating bed; a pyrolysis gas outlet of the condensing device is connected to the purifier, a purifying gas outlet of the purifier is connected to the gas inlet of the preheating device, and the preheating device is further provided with air Entrance.

The purifier is provided with another purge gas outlet, the other purge gas outlet being connected to the gas tank, the outlet of the gas tank being connected to the supplemental gas inlet of the preheating device. It is used to store excess purge gas and to supplement the gas in the preheater when needed.

The condensable liquid outlet of the condensing device is connected with a water separator to separate the bio-oil in the condensable liquid from the sewage.

The biomass pretreatment system includes one or more of a dryer, a pulverizer, and a molding machine. The beneficial effects of the regenerative biomass pyrolysis method and system thereof of the present invention are as follows:

1. The regenerative biomass pyrolysis method and system thereof according to the present invention, the pyrolysis device used is an annular rotating bed, which can continuously feed and discharge biomass raw materials, and realize single furnace by expanding the diameter of the rotating bed. Large-scale production; In addition, dehydration drying and compression molding before pyrolysis increase the biomass density and improve the processing capacity.

2. The invention adopts a regenerative gas radiant tube burner, and uses low calorific value biomass pyrolysis gas instead of purchased gas as fuel gas, which not only achieves stable combustion, but also has a combustion efficiency of more than 85%, which ensures biomass. The self-sufficiency of pyrolysis energy reduces operating costs.

3. The flue gas is separated from the pyrolysis gas during heating, and the sealing design of the rotating bed ensures that the pyrolysis is carried out under anaerobic conditions, thereby maximizing the calorific value of the pyrolysis gas.

4. Biomass pyrolysis products Pyrolysis gas, bio-oil and bio-char can be used not only as fuel, but also as industrial raw materials, with better economic value than power generation. 5. Biomass catalytic pyrolysis can significantly reduce the yield of non-target products (such as acids, ketones, carbonyl compounds), greatly reduce the oxygen content of bio-oil and increase the energy density of bio-oil, and obtain high-quality bio-oil. Another effect is to reduce the viscosity of the bio-oil, facilitating the collection and transport of bio-oil during production. DRAWINGS

1 is a schematic view showing the structure of a regenerative biomass pyrolysis system of the present invention.

2 is a schematic view showing the structure of another regenerative biomass pyrolysis system of the present invention.

Symbol mark

1 Regenerative gas radiant tube rotating bed

2 Biomass pretreatment system

3 quenching cooling device

4 condensing device

5 preheating device

6 purifier

7 gas tank

8 oil water separator

9 catalytic reactor

21 dryer

22 crusher

23 Forming machine

The implementation of the regenerative biomass pyrolysis system of the present invention is as follows:

As shown in FIG. 1, the regenerative biomass pyrolysis system of the present invention comprises a regenerative gas radiant tube rotating bed 1, and a biomass pre-connected to a feed port of the regenerative gas radiant tube rotating bed 1. a treatment system 2, a quenching cooling device 3 connected to a solid matter outlet of the regenerative gas radiant tube rotating bed 1, and a condensing device 4 connected to a gaseous substance outlet of the regenerative gas radiant tube rotating bed 1 a preheating device 5 connected to the gas inlet of the regenerative gas radiant tube rotating bed 1; a pyrolysis gas outlet of the condensing device 4 is connected to the purifier 6, and the purifying gas outlet of the purifier 6 is connected to the preheating device 5 burning The gas inlet, the preheating device 5 is also provided with an air inlet. The regenerative gas radiant tube rotating bed 1 may be a double regenerative gas radiant tube rotating bed.

The purifier 6 is provided with another purge gas outlet, and the other purge gas outlet is connected to the gas tank 7, and the outlet of the gas tank 7 is connected to the supplementary gas inlet of the preheating device 5. It is used to store excess purified gas and to supplement the gas in the preheating unit 5 when needed.

The condensable liquid outlet of the condensing device 4 is connected to a water separator 8 for separating the raw oil in the condensable liquid from the sewage.

The invention can improve the quality of the bio-oil by increasing the catalytic pyrolysis. As shown in FIG. 2, the pyrolyzed gaseous substance comes out of the regenerative gas radiant tube rotating bed 1 and enters the catalytic reactor 9, in the reactor 9 and the catalyst. Contact, catalytic conversion reaction of hydrocarbon upgrading, reducing the oxygen content and viscosity of bio-oil, increasing the energy density of bio-oil, and significantly improving the bio-oil grade. The catalytic reactor has its own independent temperature control system, which can adjust the appropriate temperature according to different reaction conditions, and the catalyst can be reused.

After the oil and gas mixture generated in the catalytic reactor 9 enters the condensing device 4 for cooling, a non-condensable liquid and a pyrolysis gas are obtained, and the pyrolysis gas enters the purifier for purification, and the non-condensable liquid is separated by the oil-water separator 8 to obtain bio-oil and sewage. .

The biomass pretreatment system 2 includes a dryer 21, a pulverizer 22, and a molding machine 23. These machines can be used in the field for drying, pulverizing or forming equipment.

The regenerative biomass pyrolysis method of the present invention comprises the following steps:

(1) The biomass is pretreated, dried, and the dried biomass is pulverized and compressed into pellets, blocks or cylinders in a molding machine, and then transported by a belt conveyor to a biomass silo, quantitatively to a rotating bed. Feeding mechanism feeding. The biomass is placed in a regenerative gas radiant tube rotating bed with a thickness of 50~400mm, and stays at a reaction temperature of 200~800°C for 30~120 minutes. The biomass is pyrolyzed in an anaerobic state, and the gaseous substance produced by Pipe collection at the top or side wall of the rotating bed. The pyrolyzed solid matter is discharged by the sealed discharge mechanism of the rotating bed.

The regenerative gas radiant tube rotating bed is the main equipment for realizing biomass pyrolysis, and includes a rotary bed pyrolysis furnace, a regenerative gas radiant tube burner, and auxiliary mechanisms such as paving and discharging. Rotating bed pyrolysis furnaces provide space and environment for the reaction of biomass pyrolysis. The regenerative gas radiant tube burner preheats the gas (air) through the regenerative burner and efficiently burns in the radiant tube to provide the heat required for biomass pyrolysis in the rotating bed by means of heat radiation. The thermal efficiency of the regenerative gas radiant tube burner is more than 85%, and more importantly, it can stably burn low-calorie gas. (2) The gaseous material coming out of the rotating bed is first cooled by a condensing device, and the condensable liquid is condensed. Condensable liquids include water, bio-oil, and solid particulates. The condensable liquid is separated by oil and water, and the obtained bio-oil can be sold as a raw material or further refined; the separated sewage is discharged after being treated by sewage.

In order to improve the quality of the bio-oil, the gaseous substance can enter the catalytic reactor after being rotated out of the regenerative gas radiant tube, and contact with the catalyst in the reactor to carry out the catalytic conversion reaction of the hydrocarbon upgrading, thereby reducing the oxygen content of the bio-oil. The amount and viscosity increase the energy density of the bio-oil.

(3) After the pyrolysis gas is purified (decoking, desulfurization, denitration), it is stored in the gas tank. The pyrolysis gas in the gas tank is connected to the regenerative burner through pressure equipment and piping, and serves as a gas source for the regenerative burner. There is also a supplemental combustion gas circuit, which provides supplemental combustion when the pyrolysis gas is insufficient or unstable. The regenerative biomass pyrolysis method and system thereof are provided, and the regenerative gas radiant tube burner is used to provide biomass. The heat required for pyrolysis, the biomass is evenly distributed on the bottom of the rotating bed and uniformly heated by the regenerative radiant tube placed on the furnace wall as the bottom of the furnace rotates, and the flue gas is isolated from the pyrolysis gas during the heating process. This method is suitable for a wide range of particle sizes, and the low calorific value gas produced by pyrolysis can be used as a fuel for a regenerative radiant tube burner, which reduces operating costs and low total energy consumption. Moreover, the rotating bed can achieve large-scale production by expanding the diameter of the furnace, and can achieve a biomass treatment scale of up to 1 million tons per year.

Claims

Claim

1. A regenerative biomass pyrolysis method comprising the steps of:

(2) Biomass pyrolysis, the biomass raw material treated in step (1) is evenly spread on the rotating bottom of the regenerative gas radiant tube rotating bed, and the raw material is in the confined space as the bottom of the furnace rotates Gradually heating, staying at a reaction temperature of 200-800 ° C for 30-120 minutes to form a gaseous substance and solid biochar; the heat in the rotating bed is provided by a regenerative gas radiant tube arranged in a rotating bed, in the radiant tube The flue gas is isolated from the gaseous matter in the rotating bed;

(3) collecting and post-treating the pyrolysis product, collecting the gaseous matter produced in the step (2), separating the pyrolysis gas and the condensable liquid by condensation, and the pyrolysis gas is used as the fuel of the regenerative gas radiant tube. The bio-oil is obtained after the condensable liquid oil and water are separated; the discharged solid biochar is collected after quenching and cooling.

2. The regenerative biomass pyrolysis method according to claim 1, wherein: the processing of the gaseous substance in the step (3) can adopt a second scheme, that is, contacting the catalyst before condensation, The catalytic conversion reaction of the hydrocarbon upgrading is carried out, and the reaction is followed by condensation.

The regenerative biomass pyrolysis method according to claim 1 or 2, wherein: the pyrolysis gas separated in the step (3) after being condensed and cooled is purified and stored in the gas tank; The pyrolysis gas in the gas tank is connected to the regenerative burner through pressure equipment and pipelines, and serves as a gas source for the regenerative burner as a gas; and a supplemental gas-fired gas path is provided, when the pyrolysis gas is insufficient or unstable Supplemental combustion

The regenerative biomass pyrolysis method according to claim 1 or 2, wherein the pretreatment of the step (1) comprises one or more of the following:

Biomass drying;

Biomass crushing;

The regenerative biomass pyrolysis method according to claim 1 or 2, characterized in that: in the step (2), the thickness of the layer of the biomass laid at the bottom of the furnace is 50 to 400 mm.

The regenerative biomass pyrolysis method according to claim 1 or 2, wherein: the gaseous substance produced in the step (2) is collected through a pipe at the top or side wall of the rotating bed, the solid Health The charcoal is discharged in the furnace with the bottom of the furnace for one week and then discharged through the sealed discharge machine.

The regenerative biomass pyrolysis method according to claim 1 or 2, characterized in that: the condensable liquid separated in the step (3) is separated by oil and water to obtain bio-oil and sewage.

8. A regenerative biomass pyrolysis system, comprising a regenerative gas radiant tube rotating bed, a biomass pretreatment system connected to a feed port of the regenerative gas radiant tube rotating bed, and the storage a quenching cooling device connected to a solid matter outlet of a rotating gas radiant tube rotating bed, a condensing device connected to a gaseous substance outlet of the regenerative gas radiant tube rotating bed, and a rotating bed of the regenerative gas radiant tube a preheating device connected to the gas inlet; a pyrolysis gas outlet of the condensing device is connected to the purifier, a purifying gas outlet of the purifier is connected to the gas inlet of the preheating device, and the preheating device is further provided with an air inlet.

9. The regenerative biomass pyrolysis system according to claim 8, wherein: the purifier is provided with another purge gas outlet, and the other purge gas outlet is connected to the gas tank, and the outlet of the gas tank is The supplementary gas inlet of the preheating device is connected.

The regenerative biomass pyrolysis system according to claim 8 or 9, wherein the condensable liquid outlet of the condensing device is connected to a water separator.

11. A regenerative biomass pyrolysis system according to claim 8 or claim 9 wherein: said biomass pretreatment system comprises one or more of a dryer, a pulverizer and a forming machine.

12. The regenerative biomass pyrolysis system of claim 8 further comprising: a catalytic reactor, said gaseous material entering said condensing unit after said catalytic reactor.

13. The regenerative biomass pyrolysis system according to claim 12, wherein: the condensable liquid outlet of the condensing device is connected to a water separator.