CN218478710U - Medium calorific value biogas production device based on high-concentration oxygen-steam gasification - Google Patents

Abstract

The utility model discloses a well calorific value biogas apparatus for producing based on high concentration oxygen-vapor gasification, including broken dry, high concentration oxygen-vapor gasification unit, the empty oxygenerator of low energy consumption, product gas purifier, isothermal methanation device, CO of living beings raw materials ₂ A separating device, a waste heat power generation device unit and the like. The utility model discloses gasification equipment is simple, and the design is low with the operation degree of difficulty, and system's internal energy recovery is abundant with recycling, and the feasibility is strong, and the scale is zoomed easily, is fit for the comprehensive utilization of resources such as town and country agriculture and forestry discarded object, domestic waste.

Description

Medium calorific value biogas production device based on high-concentration oxygen-steam gasification

technical field

The utility model provides a biomass high-quality gas production system based on high-concentration oxygen-steam gasification, which is a high-concentration oxygen-steam gasification, methanation, low-energy oxygen production, waste heat power generation and other processes. A collaborative system belongs to the fields of biomass utilization and biogas production.

Background technique

With the rapid development of society, energy and related environmental issues have become prominent. The public's demand for clean energy is increasingly urgent, especially the expectation of clean gas in the civil sector. In this context, my country's natural gas market presents the characteristics of increasing demand year by year, increasing contradiction between supply and demand, large dependence on foreign countries, large difference between peak and valley consumption in winter and summer, and large differences between rural and urban areas.

Biomass is a carbon-neutral renewable resource with abundant resources and wide distribution. Replacing fossil fuels with synthetic fuels from biomass gasification is one of the important ways to promote energy conservation, emission reduction, and structural transformation of distributed energy. Biomass gas is one of the important supplementary ways in the field of gas.

Although the biogas production method based on microbial anaerobic fermentation has been commercialized, it can produce biomass gas rich in methane, low in H ₂ , and high in safety. However, its raw materials are limited, its conversion speed is slow, its efficiency is low, and it is sensitive to changes in the external environment, which hinders the development momentum and wide application of this technology.

The gas produced based on air or low-concentration oxygen gasification has high _N2 content and low calorific value, which cannot meet the application requirements of existing combustion appliances and has poor transportation economy. In addition, the product gas obtained from gasification has high concentrations of CO and H ₂ , and is highly dangerous. It is not suitable to be directly used as civil gas, and needs to be treated by methanation process.

The thermochemical-based biomass-to-synthetic natural gas process includes steps such as steam gasification, syngas purification, methanation, crude natural gas compression, and _CO2 separation. Among them, the biomass gasification as a key link uses water vapor as the gasification medium, and generally uses a double fluidized bed, or an autothermal reactor in which combustion and gasification are carried out in partitions. The design, manufacture and actual operation of the above-mentioned gasification device are difficult, and the maintenance workload is large and the cost is high, which is not conducive to the application of small and medium-sized projects. In addition, the current mainstream dual fluidized bed gasification reactor provides the heat required for the gasification reaction by burning biomass or semi-coke. This method needs to set up a complete and complex flue gas treatment facility, which leads to complex actual process flow, a large number of auxiliary equipment, and high cost, resulting in the lack of competitiveness of gasification-based biogas.

Under the dual constraints of technology and cost, the overall development of the biomass gas industry in my country and other parts of the world is relatively slow. Therefore, improvements and innovations can be made from the perspective of gasification equipment and system integration, reducing the difficulty of designing and manufacturing gasification reactors, improving system material and energy conversion efficiency, and reducing equipment and operating costs.

Contents of the invention

The purpose of this utility model is to overcome the above-mentioned deficiencies in the prior art, and provide a high-quality gas production device based on high-concentration oxygen-steam gasification in biomass to solve the above-mentioned problems in the background technology.

The technical scheme adopted by the utility model to solve the above-mentioned problems is: a medium calorific value biogas production device based on high-concentration oxygen-steam gasification, along the material running direction, composed of a crushing and drying device, a medium-temperature heating pyrolyzer, High-concentration oxygen-steam gasifier, product gas separation and purification device, product gas condenser, synthesis gas compressor, synthesis gas cooler, isothermal methanation reactor, synthesis gas condenser, and CO2 separation device are connected in series in sequence; The inlet port of the concentrated oxygen-steam gasifier is respectively connected with the steam generator and the low-energy air separation oxygen plant, and the high-concentration oxygen-steam gasifier, the product gas separation and purification device, and the tar collector form a gas- In the tar circulation loop, inside the gasifier, oxygen reacts with some raw materials to release heat, which satisfies the heat and temperature required for the gasification reaction.

The water inlet of the isothermal methanation reactor is connected to a heater, and the heater is connected to a methanation water pump.

The low energy consumption air separation oxygen generator is connected with the waste heat power generation device.

Beneficial effect

1. The utility model is composed of high-concentration oxygen-steam gasification, low-energy air separation oxygen production, methanation, waste heat power generation and other units to cooperate to produce medium calorific value biogas. The role of high-concentration oxygen-steam gasification is in the structure Simple, operationally-aware production of low _N2 syngas within a single gasifier.

2. The gasification unit of the utility model is characterized in that: raw material drying and preheating pyrolysis all use recovered waste heat, and the heat consumption of high-temperature gasification reaction is mainly provided by the oxidation exothermic reaction of some raw materials and oxygen. For the high-temperature reaction section of the gasification, the gasification method of adding high-concentration _O2 and water vapor is adopted, which avoids the dilution of the synthesis gas by a large amount of _N2 and avoids the high energy consumption of pure oxygen required for the gasification of pure oxygen. The system achieves a good balance between the energy consumption of air separation oxygen production and the concentration of N ₂ in the syngas, and also enables gasification and heat release to occur inside a reactor, which greatly simplifies the structure of the gasification reactor and the traditional steam gasification The combustion flue gas treatment facility of the device. The main components of the synthesis gas produced by methanation are CH ₄ , CO ₂ and N ₂ , among which the concentration of CH ₄ is not lower than 35 vol.%.

3. This utility model uses high-concentration oxygen as the main gasification medium, the concentration is between 80% and 90%, and it is provided by a low-energy air separation oxygen production device. The ratio of actual oxygen supply/theoretical complete reaction oxygen consumption is 0.10 ~0.40. Due to the addition of oxygen, the tar content in the gasification product gas is reduced, which reduces the load of subsequent product gas purification.

4. After the collected tar is accumulated, it is sent to the oxidation core area through a special tar injection pipeline, and the pyrolysis and reformation of the tar is accelerated by virtue of the high temperature and reactivity characteristics of the upper area. Based on the above, zero efflux of tar is realized.

5. The production process produces a large amount of medium and high temperature heat energy, which can basically meet the power consumption demand in the production process through waste heat power generation; it can also form a gas-heat-N ₂ cogeneration system to supply industrial steam and high-concentration nitrogen to the outside world, or civilian use Heating and hot water, thereby improving overall energy efficiency and economic benefits.

6. The power consumption of the utility model system, including the power consumption of low-energy oxygen production, mainly comes from waste heat power generation; when the waste heat is insufficient, part of the generated gas is used to supplement it through the gas internal combustion engine, and the high temperature exhaust gas of the gas internal combustion engine is simultaneously supplied to waste heat power generation device, and increase its power generation; when there is a surplus of waste heat power generation, the excess power will be supplied to the local grid.

Description of drawings

Fig. 1 is the flow chart of the utility model based on high-concentration oxygen-steam gasification medium calorific value biogas production system, the main equipment and devices are:

1. Crushing and drying device; 2. Gasification water pump; 3. Steam generator; 4. Low energy consumption air separation oxygen plant; 5. High concentration oxygen-steam gasifier; 6. Product gas heat exchanger; 7. Separation and purification device; 8. Tar collector 9. Product gas condenser; 10. Compressor; 11. Isothermal methanation reactor; 12. Methanation water pump; 13. Heater; 14. Synthesis gas condenser; 15. Gas internal combustion engine; 16. Waste heat power generation device.

Detailed ways

The utility model will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. The utility model is not limited to the following implementation cases.

A medium calorific value biogas production device based on high-concentration oxygen-steam gasification of the utility model is composed of a multi-stage gasification device along the material running direction, followed by a crushing and drying device, a high-concentration oxygen-steam Gasifier, product gas heat exchanger, separation and purification device, product gas condenser, synthesis gas compressor, isothermal methanation reactor, and synthesis gas condenser are connected in series in sequence; the intake air of the high-concentration oxygen-steam gasifier The ports are respectively connected with the steam generator and the low-energy air separation oxygen plant, and the high-concentration oxygen-steam gasifier, product gas heat exchanger, separation and purification device, and tar collector form a gas-tar circulation loop.

Biomass raw materials first enter the 1. crushing and drying device for crushing and drying, and the heat source comes from the medium and low temperature waste heat recovery of product gas and synthesis gas. The temperature of the heated raw material is between 100°C and 120°C, and the water content is not higher than 20%. Then, the dried biomass enters 5. High-concentration oxygen-steam gasifier for gasification reaction in an atmosphere of high-concentration _O2 and water vapor to obtain products with CO, _CO2 and _H2 as main components gas. Gasification water is produced by 2. gasification water pump and 3. steam generator, and the required heat is product cooling and methanation heat release. High-concentration oxygen comes from 4. Low energy consumption air separation oxygen plant, the purity of O ₂ produced is between 80% and 90%, and the energy consumption is 270 kWh/t oxygen. 5. O ₂ equivalent ratio (actual oxygen supply/theoretical complete oxidation oxygen consumption, ER) range of high concentration oxygen-steam gasifier operation: 0.10~0.45. Water vapor/biomass mass ratio (S/B) range: 0.3~0.8. The gasification temperature is 700~1200℃. The gasification and oxidation of biomass can complete complex heating, pyrolysis and gasification reforming reactions in one equipment space. The heat required for gasification is mainly provided by the oxidative combustion of part of the biomass.

The high-temperature product gas generated by gasification enters the 6 product gas heat exchanger for cooling and heat exchange to recover heat, and then enters the 7. Separation and purification device to realize ash separation, product gas cooling, particulate matter filtration, and condense the trace tar and excess water in it separate. The tar is accumulated in the 8. tar collector, and after reaching a certain amount, it is injected into the reaction area with high oxygen concentration and high temperature inside the high-concentration oxygen-steam gasifier through the tar injection pipeline. With the characteristics of strong oxidation and high temperature, it promotes the cracking and reforming of tar, and realizes zero discharge of tar. The product gas enters 9. The product gas condenser continues to cool down, and the excess water is analyzed to meet the air intake requirements of the compressor.

Qualified product gas is boosted by the 10. product gas compressor, and necessary temperature adjustment is performed at the same time. In order to promote the reforming reaction of the methanation reactor and suppress carbon deposition in the reaction, a certain amount of water vapor needs to be sprayed into the methanation reactor at the same time, and the water required for methanation is processed by 11. Methanation water pump and 12. Heater. The mass ratio range of water vapor/synthesis gas: 0.6~1.0. The pressurized product gas and water vapor are introduced into 11. Isothermal methanation reactor for methanation reaction to produce synthesis gas mainly composed of CH ₄ and CO ₂ . Methanation reaction parameters are 300~400℃, 0.5~1.6MPa, and the operation mode is isothermal.

The synthetic gas obtained from methanation is cooled by the 14. synthetic gas condenser, part of the heat is recovered, and excess water is condensed and precipitated to obtain methane-enriched synthetic gas with a composition similar to that of landfill gas. According to local needs, this kind of gas can be directly supplied to the required users, or the _CO2 separation device can be used to continue to increase the calorific value.

The power consumption of the air separation unit, compressor, water pump and other devices in the system is mainly supplied by waste heat power generation. When the waste heat power generation is insufficient, it is supplemented by the gas internal combustion engine, and at the same time, the exhaust smoke of the gas internal combustion engine enters the waste heat power generation device for utilization. When the waste heat power generation is too large, it can be fed into the local power grid.

Example

Wheat straw is used as raw material for gasification, the feed rate is 125 kg/h, and the low heat value is 15.7 MJ/kg. The raw materials are preheated and dried at 110°C and then vaporized under normal pressure. The ER and S/B are: 0.21 and 0.4 respectively; the oxygen concentration is 80%. The product gas enters the condensation filter and separator, and is cooled in stages to 25 ℃ or below. Among them, the concentration of the main components of the product gas is as follows: CH ₄ : 9.0%; CO ₂ : 18.1%; CO: 35.4%; H ₂ : 34.4%; N ₂ : 3.0%, and the rest is water vapor and C _m H _n .

Using a compressor, the purified product gas is stripped to 0.65MPa. At the same time, a water pump is used to obtain methanation water at 0.7 MPa, and then the water vapor at 300 °C and about 0.65 MPa is generated through the preheater. Both streams are introduced into the isothermal methanation reactor, the water vapor/product gas ratio is 0.8, the methanation operating temperature is 300°C, and the pressure is 0.5 MPa. The concentration of the main components of the synthesis gas obtained from methanation is as follows, CH ₄ : 37.6%; CO ₂ : 53.3%; CO: 0.03%; H ₂ : 3.3%; N ₂ : 5.6%; MJ/m ³ and 13.8 MJ/m ³ . The composition of this syngas is similar to that of landfill gas. At this time, the waste heat power generation can completely meet the power consumption demand of the system, and there is a little surplus, which can be fed into the grid. In this case, the yield of biogas is 0.871Nm ³ /kg, and the energy efficiency of the system is 77.8%.

Although the utility model has disclosed the above embodiments, it is not used to limit the scope of protection of the utility model, and any technical personnel familiar with the technology, without departing from the changes made within the concept and scope of the utility model, should belong to Protection scope of the present utility model.

Claims (4)

1. A calorific value biogas production device based on high-concentration oxygen-steam gasification is characterized in that a crushing and drying device, a high-concentration oxygen-steam gasifier, a product gas heat exchanger, a product gas separation and purification device, a product gas condenser, a synthesis gas compressor, a synthesis gas cooler, an isothermal methanation reactor, a synthesis gas condenser, a gas internal combustion engine and a waste heat power generation device are sequentially connected in series along the material running direction; wherein the air inlet of the high-concentration oxygen-water vapor gasifier is respectively connected with the steam generator and the low-energy-consumption air separation oxygen generation device, and the high-concentration oxygen-water vapor gasifier, the product gas heat exchanger, the product gas separation purification device and the tar collector form a gas-tar circulation loop.

2. The apparatus for producing a medium calorific value biogas according to claim 1, wherein the isothermal methanation reactor of the isothermal methanation reactor has a water inlet connected to a heater, and the heater is connected to a water pump for methanation.

3. The medium calorific value biogas production plant based on high concentration oxygen-steam gasification according to claim 1, wherein a low energy air separation oxygen generation plant is connected with a waste heat power generation plant.

4. The apparatus for producing a medium calorific value biogas according to claim 1, wherein the high oxygen of the high oxygen-steam gasifier is supplied by a multi-nozzle design, and tar in the product gas is condensed, separated and collected, and then sprayed into a high oxygen concentration and high temperature region near a part of the oxygen nozzles, thereby burning and removing tar.

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