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US-20260124572-A1 - Process for capturing carbon dioxide using bio-digester slurry leading to manure quality improvement

US20260124572A1US 20260124572 A1US20260124572 A1US 20260124572A1US-20260124572-A1

Abstract

The present disclosure relates to a process for capturing CO 2 using bio-digester slurry, along with a method to improve the quality of fermented organic manure (FOM) and liquid fermented organic liquor (LFOM). The present disclosure describes the use of lignin functionalizing microbes (LFM) and H 2 S oxidizing microbes (SOD) to enhance the quality of the FOM and LFOM and improve the CO 2 capture ability of the slurry. The CO 2 and/or H 2 S captured manure increases their nutrient value for use in agriculture. The CO 2 absorption process not only aids in reducing the amount of greenhouse gases released into the environment, but also improves the quality of FOM and LFOM. The integration of these processes results in a sustainable and efficient approach for capturing CO 2 while improving the quality of organic waste material for agricultural use.

Inventors

  • Prakash Chandra Sahoo
  • Manoj Kumar
  • Ravi Prakash GUPTA
  • Debasis Bhattacharyya
  • Sankara Sri Venkata RAMAKUMAR

Assignees

  • INDIAN OIL CORPORATION LIMITED

Dates

Publication Date
20260507
Application Date
20251107
Priority Date
20241107

Claims (10)

  1. 1 . A process for capturing carbon dioxide using bio-digestor slurry leading to improvement in manure quality, the process comprises: feeding bio-digestor slurry obtained after biogas production into a bio-digestor slurry unit (3) of a reactor; introducing lignin functionalizing microbes (LFM) in a desired ratio into the bio-digestor slurry unit (3) and mixing the slurry for 1-2 hours; adding H 2 S-oxidising microbes (SOD) in a desired ratio into the bio-digestor slurry unit (3); sparging an off-gas composition comprising carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S) and trace amount of nitrogen into the bio-digestor slurry unit (3) using a micro bubbler to obtain a treated bio-digestor slurry. transferring the treated bio-digestor slurry from bio-digestor slurry unit (3) to a solid-liquid separation system unit (5) for separating fermentable organic matter (FOM) and liquid fermented organic manure (LFOM), wherein the off-gas composition has a liquid to gas (L/G) ratio of 15.3 to 15.6 liter/Nm 3 and is sparged for a duration of 10-15 seconds.
  2. 2 . The process as claimed in claim 1 , wherein the LFM are added in a ratio of 0.1 ml per 10% lignin content and has CFU of 10 11 per ton of bio-digester slurry.
  3. 3 . The process as claimed in claim 1 , wherein the H 2 S-oxidising microbes (SOD) are added in a ratio of 100 ml of SOD and has CFU of 10 11 per ton of bio-digester slurry.
  4. 4 . The process as claimed in claim 1 , wherein the off-gas composition is added at a flow rate of 10 m 3 /h for every 0.1% (w/w) increase in N content within the bio-digester slurry.
  5. 5 . The process as claimed in claim 1 , wherein the LFM is selected from the group consisting of Pseudomonas putida MTCC 5869, Bacillus subtilis MTCC 5851, Bacillus sp. MTCC 5870, Pseudomonas putida MTCC 5871 or a combination thereof.
  6. 6 . The process as claimed in claim 1 , wherein the SOD is selected from the group consisting of Thiobacillus sp. MTCC 25280, Thiobacillus sp. MTCC 25281, Lactobacillus sp. MTCC 25282, Mucor sp. MTCC 25283 or a combination thereof.
  7. 7 . The process as claimed in claim 1 , wherein the bio-digestor slurry is prepared from feedstocks selected from the group consisting of cattle dung, kitchen waste, organic fraction of municipal solid waste, paddy straw, and press mud.
  8. 8 . The process as claimed in claim 1 , wherein the CO 2 content in the off-gas composition ranges from 80%-99%, and wherein the H 2 S content in the off-gas composition ranges from 50-5000 parts per million (ppm), and wherein the off-gas composition has a moisture content of less than 5%.
  9. 9 . The process as claimed in claim 1 , wherein the off-gas composition is sparged into the bio-digestor unit (3) of the bioreactor using micro-bubbler of a biogas purification unit (2).
  10. 10 . The process as claimed in claim 1 , wherein the reactor is a column reactor.

Description

This application claims priority to Indian Application No. 202421085331 filed on Nov. 7, 2024. The contents of this application are hereby incorporated by reference in its entirety. FIELD OF THE INVENTION The present disclosure relates to a process for capturing carbon dioxide using bio-digestor slurry leading to improvement in manure quality. More particularly, the present disclosure relates to a process for capturing carbon dioxide using lignin de-polymerizing microbes and H2S oxidizing microbes. The process of the present disclosure not only enhances the quality of the fermented organic manure (FOM) and liquid fermented organic liquor (LFOM) but also helpful in reducing the emission of greenhouse gases into the environment. BACKGROUND OF THE INVENTION Compressed biogas (CBG) is a renewable energy source produced from organic waste materials such as agriculture residue, food waste, and municipal solid waste. While the production of CBG is considered to be an environmentally friendly alternative to fossil fuels, the process of generating CBG also produces carbon dioxide (CO2) emissions. The amount of CO2 generated per ton of compressed biogas (CBG) produced can vary depending on the specific conditions of the CBG plant. However, on average, the production of one ton of CBG can result in the generation of approximately 1.5 to 2.5 tons of carbon dioxide (CO2) emissions. This is because the process of producing CBG involves the breakdown of organic waste materials through anaerobic digestion, which results in the release of methane gas and other greenhouse gases such as CO2 as well as H2S. The purification of biogas typically involves several stages, including pre-treatment, desulfurization, and CO2 removal. During the CO2 removal stage, the biogas is passed through a pressure swing adsorption (PSA) system/amine scrubber or a membrane separation unit to selectively capture the CO2 molecules and the captured CO2/H2S is then vented. There are several methods being explored for the capture and utilization of CO2. Most of the methods require significant amounts of energy, which can negate the benefits of using it in the first place. Furthermore, some methods of CO2 utilization, such as carbon capture and storage, have raised concerns about the safety and long-term storage of captured CO2. These limitations highlight the need for continued research and development in this area to ensure that CO2 utilization can be a viable solution to reducing carbon emissions. The present disclosure overcomes the aforesaid limitations and provides a potential method of CO2 utilization involving use of bio-digester slurry to capture and store CO2 and simultaneously improve the quality of fermented organic manure (FOM) and liquid fermented organic liquor (LFOM). Bio-digester slurry is a mixture of organic matter, ammonia and water that is produced during the anaerobic digestion of organic waste. This slurry is rich in organic compounds, making it a valuable resource for various agricultural and industrial applications. Recently, there has been growing interest in using bio-digester slurry as a medium for capturing and storing carbon dioxide (CO2), a potent greenhouse gas that is a major contributor to climate change. Several prior arts exist that relate to the use of bio-digester slurry for CO2 absorption. He et.al describes a process for CO2 absorption using biogas slurry. In said process, raw biogas slurry (RBS) may be a renewable CO2 solvent to capture CO2 and fix CO2 into the crops/plants by forming organic carbon through carbon concentration mechanism (CCM). Yan et.al describes CO2 absorption by using a low-cost solvent: biogas slurry produced by anaerobic digestion of biomass. In said process, both capacity of CO2 absorption by using biogas slurry and the phytotoxicity of the formed CO2-rich biogas slurry on seeds breeding was investigated. Shivali, 2021 describes an adsorption-based hydrogen sulfide removal reactor using char and spent slurry of biodigester. In said process, biogas digested slurry for biogas desulphurization is used. The said process describes that after treatment, digested slurry gets enriched about two times with sulfur S (%) than initial sulfur S (%) present in the untreated slurry. Also, the P (%) and N (%) showed a visible increase after H2S treatment. US2023122678A1 discloses a process for preparation of fertilizer, soil additive, soil adjuvant, soil stabilizer, plant bio-stimulant, and/or mushroom growth enhancer from inorganic and organic C1 substrates by introducing these substrates in a culture medium comprising microorganisms and in presence of electron donor. Substrate includes lignocellulosic biomass and can be in liquid form. The microorganisms includes lignin de-polymerizing microbes like Rhodococcus jostii, Pseudomonas putida, Streptomyces sp., Comamonas sp., Nocardia sp. Gordonia sp., Bacillus sp., Cupriavidus sp, Mycobacterium sp., Rhodococcus erythropolis, Burkholderia sp., Arthrobacter sp