Carbon sequestration method using biomass fuel and aquatic plants

Abstract

A carbon sequestration method using biomass fuel and aquatic plants comprises the following steps: providing the biomass fuel to a boiler for combustion in the boiler, and generating combustion tail gas containing suspended particles, carbon dioxide (CO2) and trace heavy metal ions; the combustion tail gas is introduced into a washing tower, suspended particles and trace heavy metal ions in the combustion tail gas after washing are removed, washing tail gas is generated, and the washing tail gas contains CO2; the washing tail gas is introduced into an aquatic plant culture pond, and after preset time, aquatic plants exist in the aquatic plant culture pond; after the preset time, the aquatic plants in the aquatic plant culture pond are taken out and retreated. Therefore, the carbon sequestration method for the biomass fuel and the aquatic plants can be used for carbon sequestration, and the high-cost investment of carbon dioxide capture and storage and the geological risk needing to be evaluated are not needed.

Description

Technical Field

[0001] This application relates to a carbon sequestration method, and particularly to a carbon sequestration method using biomass fuel and aquatic plants. Background Art

[0002] In recent years, the world has made many corresponding regulations and restrictions to reduce greenhouse gas emissions generated by industrialization in order to mitigate the greenhouse effect. Global industries or related processes need to find processes or energy supplies with lower carbon emissions in response to the global demand for carbon neutrality and the vision of net-zero carbon emissions. Otherwise, they must pay a high green cost, and in some cases, they may not be able to sell their products to specific regions, which has a significant impact on industries or related manufacturers with high carbon emissions.

[0003] Currently, a large amount of industrial production still relies on fossil fuels as the energy supply, such as coal, oil, and natural gas. Although in recent years, cleaner energy usage methods and continuously improved energy conversion rates have emerged for each of them, they still belong to high-carbon-emission energy types. In addition, the current carbon sequestration technology is mainly Carbon Capture and Storage (CCS) technology, which captures and compresses carbon dioxide and injects it into underground layers to keep carbon dioxide isolated from the atmosphere for a long time. However, this method has problems such as high cost, high energy demand, and geological risks.

[0004] In addition, when there is a need for carbon sequestration treatment of industrial waste liquids or waste gases, there is currently a lack of a more efficient and low-cost carbon sequestration method that meets the standards for treating them. Therefore, there is an urgent need in the industry for a carbon sequestration method that can perform carbon sequestration, does not require the high-cost investment of CCS, does not require assessment of geological risks, and meets the standards. Summary of the Invention

[0005] The purpose of this application is to provide a carbon sequestration method using biomass fuel and aquatic plants to solve the problems in the prior art. The carbon sequestration method using biomass fuel and aquatic plants in this application can perform carbon sequestration to provide a low-cost, less environmentally harmful carbon sequestration method that can achieve carbon neutrality or even negative carbon emissions in the process.

[0006] The present application provides a carbon sequestration method using biomass fuel and aquatic plants, comprising the following steps: providing the biomass fuel to a boiler for the boiler to burn and generating combustion exhaust gas, wherein the combustion exhaust gas contains suspended particles, carbon dioxide (CO2) and trace heavy metal ions; introducing the combustion exhaust gas into a scrubber, after washing, the suspended particles and trace heavy metal ions in the combustion exhaust gas are removed, and washing exhaust gas is generated, wherein the washing exhaust gas contains CO2; introducing the washing exhaust gas into an aquatic plant cultivation pond and passing through a predetermined time, wherein there are aquatic plants in the aquatic plant cultivation pond; and after the predetermined time, taking out the aquatic plants in the aquatic plant cultivation pond and performing reprocessing.

[0007] In an embodiment of the present application, the aquatic plants are water hyacinth (Pontederia crassipes), duckweed (Lemna minor) or water lettuce (Pistia stratiotes).

[0008] In an embodiment of the present application, the reprocessing includes: processing the aquatic plants into animal feed.

[0009] In an embodiment of the present application, the aquatic plant cultivation pond further has a top cover for reducing the escape of CO2 introduced from the scrubber into the aquatic plant cultivation pond.

[0010] In an embodiment of the present application, the biomass fuel is industrial palm oil.

[0011] In an embodiment of the present application, the washing exhaust gas is introduced into the aquatic plant cultivation pond under pressure through one or more pressure pumps.

[0012] In an embodiment of the present application, the scrubber has granular activated carbon.

[0013] In an embodiment of the present application, before the combustion exhaust gas is introduced into the scrubber, the combustion exhaust gas is first introduced into a pre-scrubber.

[0014] Compared with the prior art, the carbon sequestration method using biomass fuel and aquatic plants in the present application can perform carbon sequestration, and reduce the amount of waste to be treated through the reprocessing step, which helps to greatly reduce the waste treatment cost, and at the same time achieve the purposes of environmental protection and energy conservation and carbon reduction. Brief Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0016] Figure 1 It is a schematic flow chart of a carbon sequestration method using biomass fuel and aquatic plants provided by an embodiment of the present application. Specific embodiments

[0017] The following introduces the preferred embodiments of the present application with reference to the accompanying drawings of the specification, demonstrating that the present application can be implemented. The embodiments of the present application can fully introduce the present application to those skilled in the art, making its technical content clearer and easier to understand. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned in the text.

[0018] In addition, the descriptions of the following embodiments of the present application refer to the attached drawings, which are used to illustrate specific embodiments in which the present application can be implemented. Terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0019] Please refer to Figure 1 As shown, it is a schematic flow chart of a carbon sequestration method using biomass fuel and aquatic plants provided by an embodiment of the present application. In an embodiment of the present application, the carbon sequestration method using biomass fuel and aquatic plants includes the following steps:

[0020] Step S101: Provide the biomass fuel to a boiler for the boiler to burn and generate combustion exhaust gas, where the combustion exhaust gas contains suspended particles, carbon dioxide (CO2), and trace heavy metal ions;

[0021] Step S102: Pass the combustion exhaust gas into a scrubber. After scrubbing, the suspended particles and trace heavy metal ions in the combustion exhaust gas are removed, and scrubbed exhaust gas is generated, where the scrubbed exhaust gas contains CO2;

[0022] Step S103: Pass the scrubbed exhaust gas into an aquatic plant cultivation pond and pass through a predetermined time, where there is an aquatic plant in the aquatic plant cultivation pond; and

[0023] Step S104: After the predetermined time, take out the aquatic plant in the aquatic plant cultivation pond and perform reprocessing.

[0024] In step S101, the present application replaces the fossil fuel in the prior art, and uses the biomass fuel to supply the boiler for combustion to generate steam, and the steam is supplied for general industrial production use, which is not the focus of the present application, so it will not be repeated here. In one embodiment, the biomass fuel is industrial palm oil. The biomass fuel after burning will produce a combustion tail gas. Due to the use of industrial palm oil, the pollution of the combustion tail gas compared to the combustion tail gas generated by the combustion of fossil fuels in the prior art has been greatly reduced, but it will still produce the combustion tail gas with NOx, SOx, CO2, suspended particulate matter (Particulate matter, PM10 or PM2.5 in the air quality standard, depending on the standards) and trace amounts of heavy metal ions, wherein the content of NOx and SOx has reached the emission standard after detection. However, after being measured by a CO2 measuring instrument, the CO2 content in the combustion tail gas is 11.8%, that is, 118,000 parts per million (ppm). Although the concentration is lower than the combustion tail gas generated by fossil fuels, it still exceeds the emission standard. In addition, after detection by heavy metal instruments, most of the heavy metals in the combustion exhaust gas are below the lower limit of instrument detection (that is, the concentration cannot be measured or there is no heavy metal), with only barium (Ba) 0.01pm, chromium (Cr) 0.04ppm, copper (Cu) 0.04ppm, iron (Fe) 3.51ppm, manganese (Mn) 0.06ppm, nickel (Ni) 0.14ppm, lead (Pb) 0.004ppm, tin (Sn) 0.01ppm and zinc (Zn) 0.08ppm, etc., showing the advantages of industrial palm oil as the biomass fuel over fossil fuels in the prior art.

[0025] Next, in step S102, the combustion exhaust gas is passed through a washing tower for washing. After washing, the suspended particles and trace heavy metal ions in the combustion exhaust gas are removed, and a washed exhaust gas is generated, wherein the washed exhaust gas contains CO2. In one embodiment, since the temperature of the combustion exhaust gas just discharged from the boiler is greater than 100°C, it is necessary to pass through a pre-washing tower before passing through the washing tower to cool it down by water. The pre-washing tower can be made of metal or alloy to avoid being melted by the combustion exhaust gas just discharged from the boiler. Compared with the pre-washing tower made of metal or alloy, since the temperature of the combustion exhaust gas has been reduced to about 50°C to 80°C after the pre-washing tower has been cooled, the washing tower can be made of polymer or plastic. Therefore, as long as the temperature requirement of the combustion exhaust gas can be met, the present application does not particularly limit what materials the pre-washing tower and the washing tower are made of.

[0026] In one embodiment, the washing liquid used in the scrubber is water. After the combustion exhaust gas is washed, the suspended particles in the combustion exhaust gas are removed, and at the same time, part of the CO2 is removed, so that the CO2 concentration in the washed exhaust gas drops to 8%, that is, 80,000 ppm, which means that it is not carried away when passing through the scrubber. Further, in one embodiment, the scrubber may have granular activated carbon, so that when the combustion exhaust gas passes through the scrubber for washing, the suspended particles and trace heavy metal ions in the combustion exhaust gas can be further adsorbed. Thus, the washed exhaust gas and the washing solution are produced after washing. The washing solution contains part of the suspended particles, CO2 (partially dissolved in water is carbonic acid), or trace heavy metal ions and other aforementioned pollutants. The washing solution is then processed through other treatment processes to meet the emission standards. The relevant subsequent processes are not the focus of this application, so they will not be elaborated here. After heavy metal instrument detection, compared with the combustion exhaust gas, there are more heavy metals in the washed exhaust gas below the lower limit of the instrument detection, as detailed below: barium (Ba): ND (non-detectable), chromium (Cr): ND, copper (Cu): 0.01 ppm, iron (Fe): 0.01 ppm, manganese (Mn): ND, nickel (Ni): ND, lead (Pb): 0.002 ppm, tin (Sn): ND, and zinc (Zn): ND. That is to say, after washing through the scrubber (and the pre-scrubber), there are almost no heavy metal ions in the washed exhaust gas, or the exhaust gas emission standards have been met.

[0027] Next, in step S103, the washed exhaust gas is further introduced into the aquatic plant cultivation pond for a predetermined time. In one embodiment, the aquatic plants are water hyacinth (Pontederia crassipes), duckweed (Lemnaminor), or water lettuce (Pistia stratiotes). Preferably, the aquatic plant is water hyacinth. Since water hyacinth has stronger tolerance to water quality and environment than other aquatic plants, and can even survive in eutrophic environments, and is a common alien species in waters, it is easy to cultivate. In addition, if the water hyacinth is obtained from the open environment, the harm of the water hyacinth as an alien species to native species can be further reduced.

[0028] When the washing tail gas is introduced into the aquatic plant cultivation pond (for example, it can be introduced through a chimney or a pipe), it is measured by a CO2 detector that the CO2 concentration in the aquatic plant cultivation pond is 61 ppm. Then, after the predetermined time, it is measured by a CO2 detector that the CO2 concentration in the aquatic plant cultivation pond has dropped to 13.5 ppm, with a reduction of about 78%. This shows that the aquatic plants have fixed carbon through photosynthesis, thereby reducing the CO2 concentration in the water. In one embodiment, the washing tail gas can also be strongly introduced into the aquatic plant cultivation pond in the form of pressurized gas through one or more pressure pumps to increase the CO2 concentration during introduction, so that more CO2 can be fixed by the aquatic plants through photosynthesis.

[0029] In one embodiment, both the predetermined time and the cultivation area of the aquatic plant cultivation pond can be adjusted according to the actual process and on-site conditions, and the present application is not limited thereto. In addition, the predetermined time needs to consider factors such as season and sunlight duration. For example, longer sunlight duration in summer and shorter sunlight duration in winter will affect the length of the predetermined time. In one embodiment, considering the fluid retention rate of the washing tail gas introduced within the predetermined time and the solubility of the pollutants it contains, the water level of the aquatic plant cultivation pond can initially be reserved with a partial liquid level height, rather than filling the aquatic plant cultivation pond completely, to allow the washing tail gas to be introduced to avoid overflow. In another embodiment, the aquatic plant cultivation pond can be enclosed. For example, the aquatic plant cultivation pond can further have a top cover to reduce the escape of CO2 into the environment during introduction, while the aquatic plants can still carry out photosynthesis.

[0030] In step S104, after the predetermined time, the aquatic plants have carried out considerable photosynthesis to fix carbon from water and CO2 in the air, and then the aquatic plants are taken out and reprocessed. In one embodiment, the reprocessing includes: processing the aquatic plants into animal feed. In some embodiments, if the aquatic plants are obtained from the external environment, there will be trace heavy metal ion residues in the roots of the aquatic plants. At this time, the roots with trace heavy metal ion residues (or those likely to have residues) can be removed through further heavy metal detection. That is to say, only the aquatic plants without heavy metal ion residues after detection can be mixed and added to the feed or food of poultry or livestock to increase nutrition.

[0031] It is worth mentioning that step S103 can be carried out in batches to avoid introducing the washing tail gas with different concentrations of pollutants in different processes into the aquatic plant cultivation pond, causing errors. In other embodiments, it can also be to measure the CO2 concentration in the water of the aquatic plant cultivation pond by a CO2 detector in cooperation with step S104 and then re-add the aquatic plants, or to introduce them into the aquatic plant cultivation pond intermittently. The present application does not limit the detailed operation methods of step S103 and step S104.

[0032] In addition, it should be particularly noted that currently, since the CO2 emissions generated after the combustion of biofuels can be excluded from the carbon emissions of greenhouse gases (but still need to meet the emission standards), the use of the carbon sequestration method of biofuels and aquatic plants in general industrial processes in this application helps to achieve carbon neutrality or even negative carbon emissions for the overall process. Thereby, it can not only meet the increasingly strict regulatory standards but also contribute to substantially reducing carbon emissions.

[0033] Compared with the prior art, the carbon sequestration method using biofuels and aquatic plants in this application can carry out carbon sequestration, and improve the nutrition by remixing the aquatic plants into the feed in the reprocessing step to reduce the amount of waste to be treated. In some embodiments, it can even reduce the amount of waste containing heavy metal ions to be treated, as well as the possible re-entry of trace heavy metal ions into the food chain or production cycle. Therefore, it helps to significantly reduce the waste treatment cost, and at the same time achieve the goals of environmental protection, energy conservation, carbon reduction, and carbon neutrality or even negative carbon emissions.

[0034] The above has introduced in detail a carbon sequestration method using biofuels and aquatic plants provided by the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A carbon fixation method using biomass fuel and aquatic plants, characterized in that: The carbon fixation method comprises the following steps: Providing biomass fuel to a boiler for combustion in the boiler and generating combustion tail gas, wherein the combustion tail gas contains suspended particulate matter, carbon dioxide (CO2) and trace amounts of heavy metal ions; Passing the combustion tail gas into a washing tower, after washing, suspended particles and trace heavy metal ions in the combustion tail gas are removed, and a washed tail gas is generated, wherein the washed tail gas contains CO2; Passing the scrubbed tail gas into an aquatic plant breeding pond for a predetermined period of time, wherein the aquatic plant breeding pond has aquatic plants; as well as After the predetermined time has passed, the aquatic plants in the aquatic plant breeding pond are taken out and reprocessed.

2. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: The aquatic plant is water hyacinth, duckweed or giant hyacinth.

3. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: The further processing comprises: processing the aquatic plants into animal feed.

4. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: The aquatic plant breeding pond further has an upper cover to reduce the escape of CO2 from the scrubbing tower into the aquatic plant breeding pond.

5. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: The biofuel is industrial palm oil.

6. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: The scrubber tail gas is pressurized and introduced into the aquatic plant cultivation pond through one or more pressure pumps.

7. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: The scrubber has granular activated carbon therein.

8. The carbon fixation method using biomass fuel and aquatic plants as claimed in claim 1, characterized in that: Before the combustion tail gas is introduced into the washing tower, the combustion tail gas is first introduced into the pre-washing tower.

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