Patent Application
20250229252
The invention, as expressed in the wording of the present specification, refers to a product that absorbs hydrogen sulphide which provides, to the function for which it is intended, advantages and characteristics, described in detail below, which represent an improvement of the present state of the art.
More specifically, the object of the invention focuses on an absorbent product whose purpose is to constitute a sustainable gas absorbent medium with low charcoal content, practically without alumina and capable of absorbing H2S (hydrogen sulphide) generated in a wide spectrum of final applications, such as an urban or waste water treatment plant, with equipment exposed to suffering corrosion or generating odors in general, with the objective of desulfurizing contaminated streams and preventing the corrosion of materials susceptible to being oxidized, either in installations or for example in packaged equipment, distinguished by the fact that the aforementioned absorbent material in pellet form, which preferably consists of a substrate impregnated with KOH (potassium hydroxide) and MgO (magnesium oxide), which has undergone an extrusion process, has a H2S removal capacity of more than 25% by weight, which represents a very competitive alternative solution in the markets specified above with respect to what is currently known, due to its lower cost and environmental footprint.
Conducting The field of application of the present invention is framed within the sector of the industry dedicated to the filtration of gases, specifically in the sector of urban or waste water purification, where complex emissions of substances with low levels of olfactory perception are generated, where H2S is one of the main pollutants to be eliminated, as well as in the sector of the industry dedicated to the application of solutions to avoid or limit corrosion by oxidation.
The Currently, a wide variety of products are available for the removal of H2S at low-moderate concentrations. However, none of these products has such a low activated charcoal content and practically no alumina as the one proposed by the present invention.
The products currently used for H2S removal can be divided into three main groups: charcoal-based products, alumina-based products and phyllosilicate-based products.
On the one hand, we have the large producers of activated charcoal, among which we find large multinational companies and Chinese companies. All of them work exclusively with pure charcoal. What does change is the origin of the coal (peat, vegetable, semi-anthracite, bituminous . . . ). In some cases, they impregnate it with KOH, KOH-KI or carbonates, and in others they move towards high value-added carbons (impregnated with metal oxides or with a specific pore size that has catalytic properties). These companies dominate the odor market through equipment using bulk charcoal, in water treatment plants, for example. For this group of companies, charcoal production is a highly costly process in terms of energy, and it is also highly polluting. To avoid such contamination, a series of measures must be taken that substantially increase the cost of the process. Initially, coal production shifted from Europe to China, where around 50% of the world's charcoal production was centralized. However, in recent years, China has been implementing strong environmental measures to reduce high levels of pollution, which has led to an increase in the price of the product. The use of charcoal is very limited, most of the production of semi-anthracite or bituminous coal is used for gas purification and these coals are not a regenerative resource. These types of companies have developed high value-added products with H2S absorption capacities between 40-70% by weight. However, for the scrubber market they offer low-cost products such as charcoals impregnated with KOH, NaOH or carbonates made from coals mostly of mineral origin of CTCs (Carbon Tetrachloride) between 50 and 60, reaching H2S removal capacity values between 10 and 20% by weight, while the economic option proposed by the Chinese market consists of impregnating coals of lower qualities, CTCs of 30-40, reaching H2S removal capacity values between 2-10% by weight.
The second group of products currently known includes companies that mix activated charcoal with activated alumina. These include Purafil (USA), Alphasorb (South Africa), recently taken over by Freudenberg (Germany), Camfil (Sweden) and AAF (American Air Filtration, USA). Reactive alumina is a raw material that gives the product very good mechanical properties in terms of hardness, but it is a very expensive product. Furthermore, worldwide, the carbon footprint of aluminum is more than 10 kg CO2/kg of aluminum (even up to 20 kg CO2/kg of aluminum in some cases). Aluminum used in Europe currently averages 8.6 kg CO2/kg of aluminum. Most of this CO2 is attributable to the electricity source. The use of “green electricity” could lower these emission levels to values around 4 kg of CO2. However, the situation today is that alumina production is a very unsustainable production. There are currently three outstanding alumina-based products on the market with good acceptance. Freudenberg's CCP 310, Purafil's Puracarb/Odorcarb and CamPure 15 achieve H2S absorption capacities of around 15, 20 and 14% by weight (according to data sheet), respectively. The alumina content of these products is between 30 and 45%, being the majority product, while powdered activated charcoal is between 20 and 35%. All three products have high market selling prices, and do not use renewable wood charcoal. This type of product is very focused on the corrosion market.
Finally, there are companies such as Bioconservación (Spain) that avoid the use of alumina by mixing it with sepiolite. This company seeks to develop high-end products using very large amounts of activated charcoal, around 30-40%. Its products have low densities, between 450 and 550 Kg/m3. However, these products have insufficient physical properties for the conditions in which they usually work, and even at high humidity levels, they may eventually decompose. Despite this, this product, due to its high capacity that can be between 60-80% by weight (according to technical data sheet), displaces in water purification module applications the equipment that was dominated by Purafil and Freudenberg. The fact that a high resistance to humidity is not necessary in applications with modules makes it an attractive product due to its high autonomy.
Currently, in a large number of cases, the price is the selling point, maintaining a minimum capacity, but products with low capacity and very economical are chosen. For this reason, and as we have already mentioned, countries such as China, with their high production capacity and lower costs, make it possible to have very cheap products. Therefore, a product such as the one developed here, with a low charcoal content (well below 35%), practically without alumina and with aluminosilicates, which provides good mechanical properties, can be a very competitive alternative solution compared to what is known for its price and technical performance.
Finally, as documents closer of the state of the art, we can mention:
However, none of them describe a product that absorbs hydrogen sulphide with all the components of the absorbent product which are the subject matter of the present invention and contained in claim 1.
The product that absorbs hydrogen sulphide which the invention proposes is an improved alternative to what is already known, the characterizing details which make it possible, and which distinguish it being conveniently set forth in the final claims accompanying the present description.
What the invention proposes, as has been pointed out above, is a gas absorbing product which advantageously is a sustainable product with low charcoal content, practically without alumina, that is to say, only with a minimum percentage of aluminum oxide, and capable of absorbing H2S (hydrogen sulphide) generated in installations such as an urban or waste water treatment plant, equipment exposed to suffer corrosion or generate odors in general, with the objective of desulfurizing contaminated currents and avoiding the corrosion of materials susceptible to be oxidized, which, preferably consists of a granulated substrate (composed of raw materials in a particle size between 1 and 500 microns), impregnated with KOH (potassium hydroxide) in flakes that is added as a liquid solution over the mixture of the rest of solid products, MgO (magnesium oxide) and a series of oxides in smaller quantities but key to its optimal operation, which has undergone an extrusion process that, once cut, gives it pellet form.
More specifically, what the invention proposes is an absorbent product composed of an exclusive mixture of porous materials in the form of granules, distinguished by the fact that said granules minimize the use of activated alumina and the use of high charcoal content, in addition to using regenerated vegetable charcoal in the formulation, which results in a product with a smaller carbon footprint, in other words, a more sustainable product.
More specifically the composition of the absorbent product object of the invention comprises a mixture of activated charcoal in vegetable powder form, a mixture of different aluminosilicates, metal oxides, a hydroxide, an amphoteric substance and a binder. The proportions of these compounds achieve the appropriate porosity that gives the absorbent a competitive capacity value and good mechanical properties.
More specifically, the product comprises zeolites, KOH, MgO, CaO, Al2O3, SiO2, Fe2O3, TiO2, NaHCO3 and powdered charcoal of plant origin.
Finally, it should be noted that the formulated absorbent material can be composed
of two distinct types of formulations:
and another with MgO, KOH and, in addition, KI (potassium iodide), seeking speed in chemisorption, essential in the corrosion market.
Furthermore, in another embodiment, the material, regardless of whether it includes KI, may also further include CuO (copper oxide).
With the introduction of this raw material (CuO), the product is particularly fast and allows reaching capacities around 45-50%, doubling that of the base formulation. Thus, the absorbent product is suitable not only for the above-mentioned applications, but also for use in biogas desulfurization.
In a preferred embodiment, the product comprises said elements in the following percentage ranges:
In a preferred embodiment, the product comprises said elements in the following percentages:
In an embodiment in which it further includes KI, KI is preferably included in a percentage of 2%. preferably, is included in a percentage of 1%.
In the following table (Table 0), a concrete example of the realization of the product is presented, in an option of the same eco for a production of 340 Kgs, where the quantity that contains the formulation of each one of its components is observed:
| Number | Date | Country | Kind |
|---|---|---|---|
| P202130994 | Oct 2021 | ES | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/ES2022/070669 | 10/20/2022 | WO |
