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EP-4739756-A1 - METHOD FOR UPGRADING BIOGAS AND SYNGAS

EP4739756A1EP 4739756 A1EP4739756 A1EP 4739756A1EP-4739756-A1

Abstract

Method for upgrading biogas or syngas wherein a raw gas (1) comprising biogas or syngas or both is provided, a concrete waste material comprising carbonatable Ca and/or Mg phases (2) is provided, and the raw gas (1) is contacted with the concrete waste material comprising carbonatable Ca and/or Mg phases (2) in a reactor (3), wherein a contact time between the raw gas (1) and the concrete waste material (2) and a weight ratio of the raw gas (1) to the concrete waste material (2) are adjusted to provide an upgraded gas (4) with a carbon dioxide concentration reduced by a factor 2 with respect to the carbon dioxide concentration in the raw gas (1) and a carbonated concrete waste material (5).

Inventors

  • SKOCEK, Jan
  • Zajac, Maciej
  • DIENEMANN, WOLFGANG

Assignees

  • Heidelberg Materials AG

Dates

Publication Date
20260513
Application Date
20240430

Claims (14)

  1. 1 . Method for upgrading biogas or syngas, wherein a raw gas comprising biogas or syngas or both is provided, a concrete waste material comprising carbonatable Ca and/or Mg phases is provided, and the raw gas is contacted with the concrete waste material comprising carbonatable Ca and/or Mg phases in a reactor, wherein a contact time between the raw gas and the concrete waste material and a weight ratio of the raw gas to the concrete waste material are adjusted to provide an upgraded gas with a carbon dioxide concentration reduced by a factor of at least 2 with respect to the carbon dioxide concentration in the raw gas and a carbonated concrete waste material.
  2. 2. Method according to claim 1 , wherein the raw gas is a biogas, obtained by anaerobic digestion of organic material, and/or a syngas, obtained from pyrolysis, thermal processing of waste, ammonia production, methanol production, hydrocarbons processing, steam reforming, partial oxidation of hydrocarbons, methane mining or two or more thereof.
  3. 3. Method according to claim 1 or 2, wherein the concrete waste material is recycled concrete fines, recycled concrete aggregates, or a mixture thereof, and/or wherein one or more of fly ash, bottom ash, slag, quarry overburden, carbide lime, spent catalyst, and slacked lime is/are added to the concrete waste material.
  4. 4. Method according to one of claims 1 to 3, wherein the carbon dioxide concentration in the upgraded gas is reduced by a factor of at least 5, preferably of at least 10, with respect to the carbon dioxide concentration in the raw gas.
  5. 5. Method according to one of claims 1 to 4, wherein the carbonation degree of the carbonated concrete waste material is at least 1 % or at least 5 % or at least 10 % or at least 20 % or at least 30 % or at least 50 % or at least 70 % or at least 80 %.
  6. 6. Method according to one of claims 1 to 5, wherein the concrete waste material is provided with a particle size distribution having a D90 < 2 mm, preferably < 500 pm, more preferred < 100 pm.
  7. 7. Method according to one of claims 1 to 6, wherein the reactor is a wet scrubber and carbonation takes place at a relative humidity of 100 Vol.-% and/or at a temperature in the range from 0 °C to 100 °C, preferably from ambient temperature or 40 °C to 60 °C, and/or at ambient pressure and/or with 2 to 15 kg of concrete waste material per m 3 of gas and/or with recirculation of the concrete waste material.
  8. 8. Method according to one of claims 1 to 6, wherein the reactor is a semi-dry scrubber at a relative humidity from 50 to 100 Vol.-% and/or at a temperature in the range from 20 to 130 °C and/or with an amount of concrete waste material ranging from 5 to 30 kg per m 3 of gas.
  9. 9. Method according to one of claims 1 to 6, wherein the reactor is a dry scrubber.
  10. 10. Method according to one of claims 1 to 6, wherein the reactor is a fluidized bed reactor or a mill, wherein preferably a temperature from 1 to 10 °C above the water dew point is adjusted in the fluidized bed reactor or mill, respectively, by water spraying and or moisturizing the concrete waste material and a residence time is set to range from 1 to 120 minutes.
  11. 11 . Method according to one of claims 1 to 6, wherein the reactor is a combination of mill and fluidized bed reactor and the concrete waste material is ground in the mill at a temperature from 1 to 10 °C above the water dew point in the presence of the raw gas, a ground and partially carbonated concrete waste material is circulated in a fluidized bed reactor in contact with the gas withdrawn from the mill optionally with added raw gas or in contact with added raw gas, and the upgraded gas and carbonated concrete waste material are withdrawn from the fluidized bed reactor.
  12. 12. Method according to one of claims 1 to 11 , wherein the carbonated concrete waste material is mixed with a hydraulic cement for use of the carbonated concrete waste material as supplementary cementitious material.
  13. 13. Method according to one of claims 1 to 11 , wherein the carbonated concrete waste material is used as aggregate in hydraulic building materials like concrete, mortar, or road binder or as gravel substitute for road and path construction.
  14. 14. Method according to one of claims 1 to 11 , wherein the carbonated concrete waste material is applied onto agricultural or horticultural cropland or in gardens for use as fertilizer or for the adjustment of the pH of cropland.

Description

Method for upgrading biogas and syngas [0001 ] The present invention relates to a method for upgrading biogas and syngas. [0002] Biogas is produced by anaerobic digestion of organic substances, for example, manures, sewage sludge, household or industrial or agricultural waste, or energy crops. Different technologies are known, like one stage, two stage and dry digestion. Also, the size of the digestors can vary widely, from small scale ones located at individual farms to large scale industrial plants. The biogas produced mainly comprises methane and carbon dioxide. Typically, biogas contains from 50 to 75 Vol.-% methane (CH4), from 25 to 50 Vol.-% carbon dioxide (CO2), from 2 to 8 Vol.-% nitrogen (N2), some oxygen and air as well as minor amounts of other impurities from the digestion like hydrogen sulfide (H2S), hydrogen (H2), volatile organic compounds (VOCs) other than methane, siloxanes etc. [0003] Thus, for use as fuel and as feed for manufacturing other products like hydrogen, the biogas usually needs to be purified. Purifying typically covers cleaning, i.e. , removal of unwanted or harmful impurities, and upgrading, i.e. , concentration of methane by separating methane from carbon dioxide. Cleaned and upgraded biogas is often designated biomethane. There are many different biogas cleaning and upgrading technologies known and available on the market. Examples include amine scrubbing, pressure swing absorption, water scrubbing, organic physical scrubbing, cryogenic distillation, and membrane separation. Each technology has different demands and efficiency rates. For example, L. Lombardi et al., “Biogas upgrading by a combination of innovative treatments based on carbonation of waste incineration residues”, Waste Biomass Valor (2015), pages 791 -803 propose to carbonate bottom ash in a fixed bed or absorb the CO2 with an alkali solution that is in turn regenerated with air pollution control residues from a waste incineration plant. A drawback of many of the known technologies is the generation of waste products that lack a beneficial use necessitating their landfilling or regenerating procedures being energy or cost intensive or both for recycling them. Also, several are energy intensive of their own. Thus, the object of upgrading biogas is still not fully solved. [0004] Similar issues arise in syngas production, e.g., syngas made by pyrolysis, where an increase of the concentrations of CO, hydrogen and other energy relevant components in the syngas and a decrease of CO2 may be desired or needed. Likewise, in methane mining it could be necessary to remove CO2 to upgrade methane for further use and distribution. [0005] It was now surprisingly found that mineral carbonation of concrete waste can selectively remove CO2 from biogas and syngas and thereby increase the concentration of energetically relevant components such as methane, CO, H2, and others. Unwanted and often harmful impurities like SOx (abbreviation for SO2, SO3 and mixtures of SO2 and SO3) and other acidic components are advantageously removed at the same time, obviating the need to separately clean the gas of them. [0006] Thus, the above-mentioned object is solved by a method for upgrading biogas or syngas, wherein a raw gas comprising biogas or syngas or both is provided, a concrete waste material comprising carbonatable Ca and/or Mg phases is provided, and the raw gas is contacted with the concrete waste material comprising carbonatable Ca and/or Mg phases in a reactor, wherein a contact time between the raw gas and the concrete waste material and a weight ratio of the raw gas to the concrete waste material are adjusted to provide an upgraded gas with a carbon dioxide concentration reduced by a factor of at least 2, preferably at least 5, and most preferred at least 10, with respect to the carbon dioxide concentration in the raw gas, and a carbonated concrete waste material. The carbonated concrete waste material may have a carbonation degree of at least 50 %, preferred at least 70 %, and most preferred at least 80 %, calculated as CaO+MgO bound as carbonate with respect to the total content of CaO+MgO. [0007] The method according to the invention has several advantages over known upgrading technologies. It is able to upgrade the raw gas without any need for prior cleaning. Acidic impurities are simultaneously removed, obviating separate cleaning steps. Mineral carbonation can take place at ambient temperature and pressure, minimizing the energy demand. No heating/cooling and/or pressurizing is needed. This also reduces the demand on the device construction. The produced carbonated concrete waste material is a useful product in itself, i.e. , it needs no regeneration nor is it a waste that must be landfilled. Depending on the concrete waste material used and the components in the raw gas the obtained carbonated concrete waste material is suitable for cropland fertilization, pH control of croplands, construction of roads, graveling, as