阅读说明：本技术 基于调控微晶结构的生物质固废水热预处理耦合气化方法 (Biomass solid wastewater thermal pretreatment coupling gasification method based on regulation and control microcrystalline structure ) 是由 张会岩 曾名迅 于 2021-09-16 设计创作，主要内容包括：本发明涉及一种基于调控微晶结构的生物质固废水热预处理耦合气化方法,包括如下步骤：将木质纤维生物质类废弃物和水以一定质量比在高压反应釜中进行不同温度和时间的水热碳化预处理；对固体产物水热炭进行X射线衍射分析,获取微晶结构信息；在固定床反应器进行水热炭的水蒸气气化实验,在线分析气化特性；将气化结果与水热炭的微晶结构进行关联,提出通过微晶结构描述原料气化特性的方法。与木质纤维生物质类废弃物直接气化相比,本发明无需提前干燥原料,通过水热预处理过程提升水热炭的能量密度和热值,提高水热炭气化合成气的产量与H-(2)/CO,并实现高效气化过程的定向调控。(The invention relates to a biomass solid wastewater thermal pretreatment coupling gasification method based on a regulation microcrystalline structure, which comprises the following steps: carrying out hydrothermal carbonization pretreatment on wood fiber biomass waste and water in a high-pressure reaction kettle at different temperatures and times according to a certain mass ratio; carrying out X-ray diffraction analysis on hydrothermal carbon of a solid product to obtain microcrystalline structure information; carrying out a steam gasification experiment of the hydrothermal carbon in the fixed bed reactor, and analyzing the gasification characteristics on line; and (3) correlating the gasification result with the microcrystalline structure of the hydrothermal carbon, and proposing a method for describing the gasification characteristics of the raw material through the microcrystalline structure. Compared with the direct gasification of the wood fiber biomass wastes, the invention does not need to dry the raw materials in advanceThe energy density and the heat value of the hydrothermal carbon are improved through the hydrothermal pretreatment process, and the yield and the H of the hydrothermal carbon gasified synthesis gas are improved 2 and/CO, and realizing the directional regulation and control of the high-efficiency gasification process.)

1. A biomass solid wastewater thermal pretreatment coupling gasification method based on a regulation microcrystalline structure is characterized by comprising the following steps:

(1) hydrothermal pretreatment: weighing solid waste materials and water in a high-pressure reaction kettle, filling inert gas to replace the original air in the kettle and sealing, putting the reaction kettle on a heating table, setting hydrothermal temperature and residence time, cooling after the reaction is finished, washing, filtering and drying the product to obtain hydrothermal carbon;

(2) characterization of hydrothermal carbon: scanning by using an X-ray diffractometer to obtain an XRD (X-ray diffraction) diffraction pattern of the hydrothermal carbon, and carrying out peak fitting on the XRD diffraction pattern to calculate the crystallinity of the hydrothermal carbon;

(3) fixed bed gasification: weighing hydrothermal carbon in a quartz boat, placing the quartz boat in a cold section at the tail part of a fixed bed reactor, setting gasification temperature and gasification time, introducing a gasification agent before the furnace temperature reaches the set temperature, pushing the quartz boat into a high-temperature area of the fixed bed reactor after the furnace temperature reaches the set temperature, carrying out gasification reaction, and pulling the quartz boat back to the cold section after the reaction is finished; in the reaction process, collecting the synthesis gas data in real time, and processing the collected synthesis gas data to obtain the yield of the synthesis gas and the volume fraction of each component;

(4) and (3) establishing relevance: and (4) repeating the steps (1) to (3) to obtain the correlation between the crystallinity of the hydrothermal carbon and the yield of the synthesis gas and the volume fraction of each component at different hydrothermal temperatures.

2. The biomass solid wastewater thermal pretreatment coupling gasification method based on the controlled microcrystalline structure according to claim 1, wherein in the step (1), the solid wastewater material is wood fiber biomass solid wastewater, and the mass ratio of the solid wastewater material to water is 1: 5-1: 15.

3. The biomass solid-waste water thermal pretreatment coupling gasification method based on the controlled microcrystalline structure as claimed in claim 1, wherein in the step (1), the hydrothermal temperature is 160-280 ℃, and the retention time is 60-180 min.

4. The biomass solid-waste water thermal pretreatment coupled gasification method based on the controlled crystallite structure according to claim 1, characterized in that in the step (2), the hydrothermal charcoal is placed on a sample stage and scanned at a diffraction angle 2 θ ranging from 5 to 90 ° in steps of 0.02 ° and at a speed of 4 °/min.

5. The biomass solid wastewater thermal pretreatment coupling gasification method based on the controlled microcrystalline structure according to claim 1, wherein in the step (3), nitrogen is firstly introduced into the fixed bed reactor before the gasifying agent is introduced, and the gasification temperature and the gasification time are set; the gasifying agent is steam, the steam flow rate and the nitrogen flow rate are the same, the gasifying temperature range is 800-1000 ℃, and the gasifying time is 30-90 min.

6. The biomass solid wastewater thermal pretreatment coupling gasification method based on the regulation and control microcrystalline structure as claimed in claim 1, wherein an outlet of the fixed bed reactor is connected with a purification and drying device and a gas analyzer, the purification and drying device is composed of ethanol, water, absorbent cotton and allochroic silica gel and is used for absorbing tar and moisture in a product, and the purified product is introduced into the gas analyzer for on-line analysis.

Technical Field

The invention relates to the technical field of biomass resource treatment, in particular to a biomass solid waste water thermal pretreatment coupling gasification method based on a regulation microcrystalline structure.

Background

Gasification is a common thermal conversion technique, and at a certain temperature, a sample is gasifiedA series of reactions of agents (usually one or more of air, water vapor or carbon dioxide) can be carried out to obtain CO and H₂A predominantly synthesis gas. The problems of low energy density, nonuniform dimension, nonuniform heat and mass transfer and the need of drying raw materials in advance exist when the wood biomass waste is directly gasified and utilized.

Hydrothermal carbonization is a common pretreatment means, and generally takes biomass materials as raw materials, takes water as a solvent and a reaction medium, and performs hydrolysis, polycondensation, aromatization and other reactions at a certain temperature and pressure to obtain the hydrothermal carbon which takes carbon as a main body and has rich surface functional groups. The hydrothermal carbonization pretreatment does not need to dry the raw materials in advance, so that the treatment of the raw materials which are easy to be wet is very convenient. The hydrothermal carbon obtained after hydrothermal carbonization has the quality close to that of lignite in terms of energy density, the hydrophobicity and the grindability are greatly improved, and the size of the hydrothermal carbon is more uniform, so that the hydrothermal carbon has obvious advantages in gasification and utilization.

The storage capacity of the wood fiber biomass solid wastes is large, the growth speed is high, and the wood fiber biomass solid wastes are an important component of the municipal solid wastes. Hydrothermal carbonization is an effective means for efficiently disposing and utilizing municipal domestic garbage, and the solid waste of wood fiber biomass is a key component determining the effect of hydrothermal reaction. Compared with components such as sludge and kitchen waste in municipal domestic waste, cellulose, hemicellulose and lignin contained in the lignocellulosic biomass solid waste are difficult to convert during hydrothermal carbonization, and the generated reactions such as hydrolysis, polycondensation and the like can cause the change of crystallinity in the hydrothermal carbon structure and influence the gasification characteristics of the hydrothermal carbon structure.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a biomass solid-waste water thermal pretreatment coupling gasification method based on a regulation microcrystalline structure, which describes the gasification characteristic of raw materials through the microcrystalline structure, thereby achieving the purpose of obtaining high-quality synthesis gas by utilizing hydrothermal carbon gasification.

The technical scheme adopted by the invention is as follows:

a biomass solid wastewater thermal pretreatment coupling gasification method based on a regulation microcrystalline structure comprises the following steps:

(1) hydrothermal pretreatment: weighing solid waste materials and water in a high-pressure reaction kettle, filling inert gas to replace the original air in the kettle and sealing, putting the reaction kettle on a heating table, setting hydrothermal temperature and residence time, cooling after the reaction is finished, washing, filtering and drying the product to obtain hydrothermal carbon;

(2) characterization of hydrothermal carbon: scanning by using an X-ray diffractometer to obtain an XRD diffraction pattern of the hydrothermal carbon, performing peak fitting on the XRD diffraction pattern, and calculating the crystallinity of the hydrothermal carbon;

(3) fixed bed gasification: weighing hydrothermal carbon in a quartz boat, placing the quartz boat in a cold section at the tail part of a fixed bed reactor, setting gasification temperature and gasification time, introducing a gasification agent before the furnace temperature reaches the set temperature, pushing the quartz boat into a high-temperature area of the fixed bed reactor after the furnace temperature reaches the set temperature, carrying out gasification reaction, and pulling the quartz boat back to the cold section after the reaction is finished; in the reaction process, collecting the synthesis gas data in real time, and processing the collected synthesis gas data to obtain the yield of the synthesis gas and the volume fraction of each component;

(4) and (3) establishing relevance: and (4) repeating the steps (1) to (3) to obtain the correlation between the crystallinity of the hydrothermal carbon and the yield of the synthesis gas and the volume fraction of each component at different hydrothermal temperatures.

Specifically, the hydrothermal carbon crystallinity and the synthesis gas parameters are subjected to fitting correlation.

The further technical scheme is as follows:

in the step (1), the solid waste material is wood fiber biomass solid waste, and the mass ratio of the solid waste material to water is 1: 5-1: 15.

In the step (1), the hydrothermal temperature is 160-280 ℃, and the retention time is 60-180 min.

In the step (2), the hydrothermal carbon was placed on a sample stage, and scanning was performed at a diffraction angle 2 θ ranging from 5 to 90 ° with a step size of 0.02 ° and a speed of 4 °/min.

In the step (3), before the gasification agent is introduced, nitrogen is introduced into the fixed bed reactor, and the gasification temperature and the gasification time are set; the gasifying agent is steam, the steam flow rate and the nitrogen flow rate are the same, the gasifying temperature range is 800-1000 ℃, and the gasifying time is 30-90 min.

The outlet of the fixed bed reactor is connected with a purification and drying device and a gas analyzer, the purification and drying device is composed of ethanol, water, absorbent cotton and allochroic silica gel and is used for absorbing tar and moisture in the product, and the purified product is introduced into the gas analyzer for on-line analysis.

The invention has the following beneficial effects:

the invention characterizes the carbon microcrystal structure of hydrothermal carbon through crystallinity, clarifies the regulation mechanism of hydrothermal conditions on the carbon microcrystal structure of the hydrothermal carbon, associates the crystallinity of the hydrothermal carbon with the quality parameters of synthesis gas, and provides a method for describing the gasification characteristics of raw materials through the microcrystal structure.

The invention adjusts and controls the crystallinity of the hydrothermal carbon by changing the hydrothermal condition, the lower the crystallinity of the hydrothermal carbon, the lower the ratio of the crystalline carbon is, the higher the amorphous carbon is, the gasification characteristic is improved, and the gasification characteristic is mainly reflected in that the yield of the synthesis gas is increased, and the H content of the synthesis gas is increased₂the/CO ratio increases.

According to the invention, the reaction temperature range of the hydrothermal kettle is set to be 160-280 ℃ and the reaction time is set to be 60-180 min, so that the biomass raw material can be reacted for a sufficient time in the reactor, relatively high hydrothermal carbon solid yield is obtained on the premise of ensuring the carbonization degree, sufficient pressure supply can be carried out in the reactor through the steam pressure intensity range in the reaction kettle being 1-4 MPa, the hydrothermal reaction rate between the raw material and water is accelerated, the gasification temperature of the fixed bed reactor is set to be 800-1000 ℃ and the gasification time is set to be 30-90 min, the steam and nitrogen flow rate are ensured to be the same, so that the hydrothermal carbon and the gasification agent are subjected to gasification reaction fully, the conversion rate and the hydrogen yield are improved, and high-quality synthetic gas is obtained.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention.

FIG. 2 is a schematic diagram showing the relationship between the calorific value (HHV) and the Energy Density (Energy Density) of the hydrothermal carbon at different hydrothermal temperatures according to an example of the present invention.

FIG. 3 is a schematic diagram of the syngas yield (Gas yield) of hydrothermal char gasification at different temperatures according to an embodiment of the present invention.

FIG. 4 is a Gas composition distribution plot for various syngas compositions at various temperatures according to embodiments of the present invention.

FIG. 5 shows the crystallinity (Cl%) and H of hydrothermal carbon in accordance with an embodiment of the present invention₂Correlation diagram of/CO.

FIG. 6 shows the crystallinity (Cl%) of hydrothermal carbon and the total yield (Y) of syngas for examples of the present invention_g) The correlation diagram of (1).

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

The biomass solid wastewater thermal pretreatment coupling gasification method based on the regulation and control microcrystalline structure can refer to fig. 1, and includes the following steps:

(1) hydrothermal pretreatment: weighing solid waste materials and water in a high-pressure reaction kettle, filling nitrogen to replace the original air in the kettle and sealing, putting the reaction kettle on a heating table, setting hydrothermal temperature and residence time, cooling after the reaction is finished, washing, filtering and drying the product to obtain hydrothermal carbon;

(2) characterization of hydrothermal carbon: scanning by using an X-ray diffractometer to obtain an XRD (X-ray diffraction) diffraction pattern of the hydrothermal carbon, and carrying out peak fitting on the XRD diffraction pattern to calculate the crystallinity of the hydrothermal carbon;

(3) fixed bed gasification: weighing 0.5-5 g of hydrothermal carbon in a quartz boat, placing the quartz boat in a cold section at the tail part of a fixed bed reactor, setting gasification temperature and gasification time, introducing a gasification agent before the furnace temperature reaches the set temperature, pushing the quartz boat into a high-temperature zone of the fixed bed reactor after the furnace temperature reaches the set temperature, carrying out gasification reaction, and pulling the quartz boat back to the cold section after the reaction is finished; in the reaction process, collecting the synthesis gas data in real time, and processing the collected synthesis gas data to obtain the yield of the synthesis gas and the volume fraction of each component;

(4) and (3) establishing relevance: and (4) repeating the steps (1) to (3) to obtain the correlation between the crystallinity of the hydrothermal carbon and the yield of the synthesis gas and the volume fraction of each component at different hydrothermal temperatures.

Specifically, the hydrothermal carbon crystallinity and the synthesis gas parameters are subjected to fitting correlation.

In the above embodiment, in the step (1), the solid waste material is wood fiber biomass solid waste, and the mass ratio of the solid waste material to water is 1: 5-1: 15.

In the above embodiment, in the step (1), the hydrothermal temperature is 160-280 ℃ and the retention time is 60-180 min.

In the above example, in step (2), the hydrothermal carbon was placed on a sample stage and scanned at a diffraction angle 2 θ in the range of 5 to 90 ° in a step size of 0.02 ° and at a speed of 4 °/min.

Specifically, the crystallinity calculation formula is:

degree of crystallinity ═ ((002) peak height- (101) peak height)/(002) peak height;

wherein the (002) peak is a characteristic peak for crystalline carbon, (2 θ) is about 22 °, (101) peak is a characteristic peak for amorphous carbon, and (2 θ) is about 15 °.

In the above embodiment, in the step (3), before the gasifying agent is introduced, nitrogen is introduced into the fixed bed reactor, and the gasifying temperature and gasifying time are set; the gasifying agent is steam, the flow rate of the steam is the same as that of nitrogen, the gasifying temperature range is 800-1000 ℃, and the gasifying time is 30-90 min.

The pressure intensity of the vapor pressure is 1-4 MPa.

In the above embodiment, the outlet of the fixed bed reactor is connected to the purification and drying device and the gas analyzer, the purification and drying device is composed of ethanol, water, absorbent cotton and allochroic silica gel and is used for absorbing tar and moisture in the product, the purified product is introduced into the gas analyzer, and the gas analyzer is used for online detection of the components of the synthesis gas.

The coupled gasification process of the present invention is further illustrated by the following specific examples.

The method comprises the following steps:

step (1), carrying out hydrothermal pretreatment, weighing poplar sawdust, wherein the mass ratio of the sawdust to water is about 1: 10, taking 3g of poplar sawdust and about 30mL of water. The hydrothermal temperature is 180 deg.C, 200 deg.C, 220 deg.C, 240 deg.C, and the retention time is 120 min.

Step (2), representing hydrothermal carbon, namely weighing 1g of the hydrothermal carbon generated in the step (1), placing the hydrothermal carbon on a sample table, scanning by using an X-ray diffractometer, and scanning in a range of a diffraction angle 2 theta between 5 and 90 degrees at a step length of 0.02 degrees and a speed of 4 degrees/min to obtain an XRD diffraction pattern of the hydrothermal carbon;

and (3) in fixed bed gasification, adopting steam as a gasification agent, wherein the steam flow rate and the nitrogen flow rate are the same and are both 0.4L/min, the gasification temperature is 900 ℃, and the gasification time is 120 min. The gas analyzer is set in an on-line detection mode, the components of the passing gas are detected at intervals of one second, and the components of the synthesis gas are mainly detected as H₂、CO、CO₂And CH₄。

And (4) establishing correlation, and calculating the crystallinity by adopting the crystallinity calculation formula according to the XRD diffraction pattern. And integrating the synthetic gas data acquired by the gas analyzer to obtain the synthetic gas yield and the volume fraction of each component, and performing fitting correlation on the hydrothermal carbon crystallinity and the synthetic gas parameters.

Specifically, the hydrothermal condition is clear to directionally regulate and control the crystallization degree mechanism of the hydrothermal carbon, and the crystallization degree of the hydrothermal carbon is calculated, and the results are shown in the following table:

as shown in fig. 2, after the poplar sawdust was subjected to hydrothermal pretreatment, the heat value and energy density were improved. Fig. 3 and 4 are schematic diagrams showing the yield and composition of gasification products of gasification reaction of poplar sawdust (PW) without being subjected to hydrothermal carbonization treatment and hydrothermal char treated by hydrothermal carbonization at 180 ℃ (HTC180), 200 ℃ (HTC200), 220 ℃ (HTC220), and 240 ℃ (HTC240), respectively, under the same conditions. As can be seen from the figure, the yield and the relative volume fraction of each component of the synthesis gas gasified by the hydrothermal carbon are improved, and the overall gasification effect is improved.

The crystallinity of the hydrothermal carbon is calculated by an XRD (X-ray diffraction) map, the regulation mechanism of the hydrothermal temperature on the microcrystalline structure of the hydrothermal carbon is clarified, and the crystallinity of the hydrothermal carbon is reduced along with the increase of the hydrothermal temperature, so that the increase of the hydrothermal temperature is proved to reduce the content of crystalline carbon in the hydrothermal carbon and increase the amorphous carbon structureMuch more. The correlation between the degree of crystallization of the hydrothermal carbon and the parameters of the gasified gas is shown in FIGS. 5 and 6, and it can be seen that the yield of the gasified synthesis gas and H are obtained₂the/CO and the hydrothermal carbon microcrystal structure have better negative correlation, so that the corresponding gasified gas yield and H can be obtained by representing the hydrothermal carbon microcrystal structure according to the correlation₂and/CO, further realizing the directional regulation of the hydrothermal carbon microcrystal structure by improving the hydrothermal temperature, and further obtaining high-quality synthesis gas by utilizing hydrothermal carbon gasification.

The invention defines the influence of hydrothermal conditions on the hydrothermal carbon microcrystal structure and the relevance of the hydrothermal carbon microcrystal structure and the quality of the gasified synthesis gas, and directionally regulates and controls the carbon microcrystal structure of the hydrothermal carbon to obtain the high-quality synthesis gas.