ES2472267B2 - Filter material for gaseous streams - Google Patents

Abstract

Filter material for gaseous streams, consisting of natural hair, preferably natural hair from pickled fur of animal skins. # Once the hair is collected, it is dried, to a humidity between 60-20% by weight and then to a degreasing process, up to a maximum fat content of 30% by weight.

Description

FILTER MATERIAL FOR GASEOUS CURRENTS

FIELD OF THE INVENTION

The present invention relates to a filter material for gaseous streams, constituted from an organic residue, capable of removing certain contaminating compounds from a gaseous stream. 5

The object of the invention is also the process for preparing the filter material.

BACKGROUND OF THE INVENTION

The use of biofiltrant materials or filters is well known in the field of gas stream treatment. 10

The biological treatment of different pollutants present in gaseous effluents is an alternative chosen mainly for its low operating costs and its reduced environmental impact compared to other systems such as gas scrubbers, water traps, chemical treatments, chemical neutralizers, etc.

A biofilter is a technology based on harnessing the oxidative capacity of biomass 15 to oxidize polluting compounds, in this case of air. It is necessary to promote optimal conditions for the development of the microorganisms that carry out the process. For this, a support medium is available, usually based on natural materials with a high surface / volume ratio and that can provide nutrients to the bacteria, thus facilitating the formation of a biofilm or film of microorganisms. Bacteria 20 use pollutants as a source of carbon and energy, together with oxygen they form CO2, H2O and various salts. This process must take into account absorption, adsorption and biological degradation.

In some cases plastic materials in the form of pellets or gratings are used, in other applications active carbons or volcanic rocks are used and in other cases 25 organic supports are chosen. Porosity, mechanical cohesion in water, moisture retention capacity and medium density are important parameters when validating the support materials formulated for application in biofilters.

The use of inorganic filter materials is described, for example, in MX2009013966A and in US20060148633A-1. Supports based on organic waste are described in ES2285173T3 and BE102009049346A1.

However, in none of the aforementioned cases does the filtering material of the organic type satisfy the main desirable characteristics for such a filter, such as:

- The material must be stable

- The characteristics of the material should promote the adhesion or colonization of microorganisms

- Support that generates low load losses

- Ability to buffer pH 10

- Moisture of the support to guarantee microbial activity even without the addition of water, supplementary irrigation

- Absorption of objective compounds

- The production of the selected material should be carried out as economically as possible while minimizing waste generation 15

- In the context of sustainable development, the selected material should be natural and subject to recycling or recovery after use as a filtration material and that offers improved operating conditions.

DESCRIPTION OF THE INVENTION 20

The present invention is intended to provide a filter material that provides all the features listed above.

According to the invention, the filter material is constituted based on natural hair, preferably natural hair from the fur of the pickling of animal skins, this natural hair having a humidity comprised between 60 and 20% by weight and a maximum content of 30% fat. Preferably the moisture content will be between 35 and 25% by weight and the fat content will be between 0 and 10% by weight. 30

The skin tanning process involves removing the epidermis and hair from the skin to be treated.

Currently, and according to the type of industrial installation, a residue is generated in this phase that is formed by the hair and a small organic part attached. The management of this waste is done either with landfill deposit or by including it in composting processes mixing with very different types of organic waste. 5

This product is heterogeneous in terms of composition, since it is composed of the hair itself, and organic and aqueous fatty residues.

The hair offers a fabric that provides structure to the material as a support and increases the specific surface.

The object of the invention is also the process for the preparation of the material 10 described above. This procedure includes the steps of:

a) Collection of natural hair from pickled fur of animal skins;

b) Drying the collected hair until reaching a humidity between 60-20% by weight; fifteen

c) Subject the hair to a degreasing process, until a maximum fat content of 30% by weight is achieved; Y

d) Fill the chamber or filter chambers with dried and degreased hair.

The filter material obtained in accordance with the process of the invention has the following characteristics:

- The protein that the hair is made of offers stability and durability to the material and the structuring fraction of the biofilter.

- Analyzed the content of nutrients such as nitrates and phosphates the hair has considerable concentration so it can be considered that the bed will not have problems due to lack of these nutrients. 25

Analyzing the humidity of the support, it is maintained around 30%, always being greater than 20%, although there is no irrigation, so it is expected that biological activity will occur sufficiently in this material.

For these two reasons, the fact that the chosen material effectively promotes the adhesion or colonization of microorganisms is based. 30

- During the biofilter conditioning phase, the loss of load decreases, reaching optimum load loss levels.

- The ability to buffer the pH of the support material has been tested and it has been verified that as the load of H2S in the biofilter increases, the initial pH of the solid becomes more acidic but in a buffered manner, which means that the 5 filler well supports acid generation during compound removal.

- Bed moisture is maintained at adequate levels even without the need for additional irrigation, which implies lower associated operating costs.

- After the period of operation, the sulphide content directly associated with the absorption capacity of target compounds such as 10 H2S has been controlled, verifying that the absorption phenomenon is very effective in this support.

- The pretreatment operations necessary for the conditioning of the support are simple in terms of execution and do not imply a significant additional cost. In addition, the product chosen and characterized as support is currently a waste for which the generating companies have to pay to ensure proper management. Finally, the product that is generated once it has finished its useful life as a support for biofiltration, can be used directly as fertilizer in the field.

The use of this material as a biofiltration bed is ideal in a context of sustainable development, since it is based on the rehabilitation of an organic waste that can be reused in the preparation of fertilizer after its useful life as a support in biofiltration. In addition, it is proven that during its operation it allows improvements such as the saving of additional irrigation, which also affects the sustainable vision of this invention.

DESCRIPTION OF AN EXAMPLE OF EMBODIMENT 25

The filter material of the invention has been validated for biofiltration of nitrogen and sulfur odoriferous compounds. Specifically for ammonia and hydrogen sulfide.

In this case, the prior adaptation of the pellet residue support has been carried out as follows:

- Drying 30

- Stabilization

The design of the support has been carried out with a mixture of 80% fur residue and 20% fertilizer pellet.

The installation designed for the validation process is as shown in figure 1. It consists of 3 modules 1, 2 and 3 support containers connected to each other with rigid tube 4 and connected in point 5 with the effluent outlet of the installation industrial pipe 5 and at point 6 at the exit of the system with a blower that drives the air through the biofilter.

The validation for each of the 2 compounds has been of 2 months duration plus 1 month of conditioning of the system.

Typical operating conditions for the treatment of gases are as shown in Table 0 below.

The filter material of the invention has been validated for biofiltration of nitrogen and sulfur odoriferous compounds. Specifically for ammonia and hydrogen sulfide.

In this case, the prior adaptation of the pellet residue support has been carried out as follows:

- drying

- Stabilization

The design of the support has been carried out with a mixture of 80% fur residue and 20% fertilizer pellet.

The installation designed for the validation process is as shown in Figure 1. 20 It consists of 3 modules 1, 2 and 3 support containers connected to each other with rigid tube 4 and connected at point 5 with the effluent outlet of the industrial installation by pipe and at point 6 at the exit of the system with a blower that drives the air through the biofilter.

The validation for each of the 2 compounds has been 2 months long plus 1 25 months of system conditioning.

Typical operating conditions for the treatment of gases are as shown in Table 0 below.

Table 0. Typical operating conditions for gas treatment.

 Parameter

 Typical values

 Biofilter fill height

 1 - 1.5 m

 Biofilter area

 1 - 3,000 m2

 Airflow

 50 - 300,000 m3 h-1

 Biofilter surface charge

 5 - 500 m3m-2h-1

 Biofilter volumetric load

 5 - 500 m3m-3h-1

 Empty volume of liquid

 fifty %

 Residence time for medium effectiveness

 15 - 60 s

 Pressure loss per meter of bed height

 0.2 - 1.0 cm water (max. 10 cm)

 Input load and odor concentration

 0.01 - 5 gm-3, 500 - 50,000 OUm-3

 Operating temperature

 15-30 ° C

 Relative humidity of inlet air

 > 98%

 Water content of the bed

 60% by mass

 pH of the medium

 6 - 8

 Typical removal efficiency

 60 - 100%

The results obtained in industrial facilities with gaseous effluents that have both ammonia and hydrogen sulfide are shown in Table 1. 5

Table 1. Results of substrate validation compared to other bibliographic data

 % removal Relative efficiency

 H2S NH3

 Substrate 80% hair 20% pellet

 > 99.9%> 99.9%

 Magellanic peat (Chile)

 > 99.9% 95%

 Cane bagasse (Colombia)

 > 99% -

 Biological activated carbon

 > 99% 95%

 UP20 (contains CH4N2O, H3PO4, CaCO3 and organic cover)

 93% -

 Pine bark

 69% 64 - 93%

 Volcanic rock

 74% -