BE1018840A3 - UNIVERSAL METHOD WHICH MAKES THE CONVERSION OF THE ORGANIC FRACTION IN WASTE TO BIOGAS. - Google Patents

Abstract

The invention relates to a universally applicable waste treatment method in which the organic substances in waste, originating from both synthetic and biological processes, are processed under high pressure and at high temperature with a very strong base into a sterile and prion-protein-free substance which is subsequently anaerobic fermentation can be converted into biogas and high-quality compost.

Description

Universal method that allows the conversion of the organic fraction in waste to biogas1.

1. Description of the invention (1 of 13):

Technology to which this invention relates

The invention relates to methods for producing biogas, in particular methods for producing biogas from the organic components in waste. This invention makes it possible to convert the organic fraction into waste, with a widely varying composition, into biogas. Waste from a very diverse origin is suitable, such as household waste, waste from hospitals, catering (hotels, restaurants), but also from farms, the meat and fish industry, the food industry, the paper and wood industry, the plastic industry or in its Generally, industries and sectors that produce a substantial amount of organic waste. The method to which this invention relates relates to a saponification of the organic waste with a very strong base, at a temperature of 225 degrees Celsius and 25 bar pressure. Through this pre-treatment, an aqueous substance is obtained in which the organic components from the waste are converted into biogas and compost by an anaerobic fermentation.

Background information

Goods are currently being produced with the aim of not making them the best price / quality ratio, but not enough attention is paid to the fact that irrevocable waste remains after making and using the products. Structure, organization and discipline are needed to ensure that recycling in advance forms an integral part of the design, development and production of the goods. In general, waste processing is a growing concern for society for a variety of reasons: environment, health, economic and logistical limitations. Most OECD countries have built incineration plants as their main alternative to waste processing in addition to landfilling. The "cradle-to-cradle" philosophy has been strongly promoted and supported, but the impact on waste processing is limited, mainly due to economic constraints. Incineration plants convert the energy in the waste into electricity. The conversion efficiency is mediocre, usually only 20-30% of the energy is converted to electrical energy. The by-product of this process is the combustion heat that is lost unless the region has a well-developed district heating system. Currently, district heating systems are not widely distributed, which means that for the majority of the

Further description of the invention (2 of 13: incineration plants about 70-80% of the energy content of the waste is lost. This loss of energy is regrettable, because the loss must be compensated completely unnecessarily by man or nature, a loss that must be compensated for by the use of biological or fossil raw materials Apart from the low efficiency of the incineration plants, environmental problems are associated with the incineration of the waste, for example the emission of toxic substances, as well as the presence of heavy metals in the slag .

The public has a great interest in developing and implementing more ecologically and economically friendly waste processing processes. Both the incineration and the dumping of waste must be seen as a temporary solution which is not acceptable in the longer term.

Other methods for recovering the energy content of the waste have been investigated and / or considered such as direct gasification of waste, plasma arc gasification of waste, mechanical biological treatment, waste autoclave, pyrolysis, thermal decomposition, hydrothermal treatment for the production of carbides, etc. The economic and / or environmental effects of these rather exotic processes are often not favorable and as a result, these processes do not offer an attractive alternative.

Summary

The invention relates to a universally applicable pre-treatment method for waste with a widely varying composition, wherein the organic fraction is converted into the waste by this treatment into a substance suitable for extracting methane and a high-quality compost from it by anaerobic fermentation. The method consists of treating the waste with soda or potassium hydroxide at a temperature of approximately 225 degrees, a pressure of 25 bar for 1 hour, which makes it possible to saponify the synthetic and biological polymers during this pre-treatment and / or to depolymerize and disintegrate the organic material present.

This universally applicable pre-treatment method is an addition to the existing waste treatment methods. In most plants that produce biofuels, it is customary to separate the biomass from the other waste when processing waste. The biomass is fermented, resulting in the production of biofuel. Plastic, textiles (clothing, etc.) and wood, despite the fact that these materials are also organic compounds, are not

Continued description of the invention f3 of 13Ί: used because the direct anaerobic fermentation of these materials is not possible. The combination of this invention with the existing fermentation techniques allows the conversion of organic material into waste, of any composition whatsoever, into biogas and a high-quality compost with an efficiency of more than 80% or even higher when developers, designers and producers of constructively integrate the recycling of the goods into their respective decision-making processes.

DETAILED DESCRIPTION OF THE INVENTION

The invention offers a better alternative to treat waste in a more environmentally friendly manner, which also results in a higher energy yield.

In general, anaerobic fermentation methods and processes for the production of ethanol, biogas or other biofuels consist of five or more process steps: 1. Sorting and grinding 2. Pre-treatment 3. Hydrolysis and / or fermentation (anaerobic fermentation) 4. Extraction of end product ( and) 5. Separation of the digestate

The universal pre-treatment method described in this invention is suitable for the treatment of all waste that consists for a substantial part of organic substances.

Chemically, waste can be divided into an inorganic and organic fraction. The inorganic fraction cannot be converted into energy. The majority of the inorganic fraction contains glass, concrete, ceramics and metal, which are previously separated and recycled via processes specifically designed for this purpose.

The "energy" is stored in the organic fraction of the waste. The organic fraction consists of material from both biological and synthetic sources. Biological waste is, for example, food and garden waste, animal waste, including manure and slaughter waste, paper and wood, organic oils and fats, cotton, silk, wool, linen and also biological plastics such as: thermoplastic cellulose, polyhydroxyalkanolates (e.g. polycaprolactone) polylactate, polyethylene succinate, polybutylene succinate, polybutylene adipate), generally polyalkyl esters and polyalkyl aryl esters.

Synthetic organic waste mainly consists of polymers, the majority is formed by plastic packaging and textiles. A large number of polymers falls

Continue description of the invention (4 of 13V.

apart during the chemical pretreatment of this invention. During the treatment, the macromolecules are broken down into their respective building blocks (monomers) or oligomers of these building blocks. The degradation occurs by the saponification of the polymer and / or the gradual reduction of the polymerization degree of the polymer.

In general, the polymers produced by polycondensation such as: polycarbonates, polyesters (e.g., PET-PBT-PNT), polyamides, polyimides, and polysulphones are saponified during the chemical pretreatment of this invention.

Polymers whose degree of polymerization gradually decreases during chemical pretreatment are, for example, polyvinyl alcohol (PVA) and PVA derivatives, super-absorbent plastic such as sodium polyacrylate and copolymers thereof. Polymers that do not decompose into smaller units, as a result of which the conversion to biogas by the microorganisms in the hydrolysis and fermentation step following the pre-treatment is not automatically possible, require the addition of prodegradants or pro-oxidants. In general, the polymers produced by polyaddition, such as polystyrene, polyethylene, polypropylene, etc., do not decompose and must be removed from the produced mixture prior to the hydrolysis and fermentation step together with all other materials that do not saponify or disintegrate dissolved in small fermentable particles or finely divided in the substance to be fermented.

Household waste is probably a good example of waste with a very varied composition. Household waste consists on average of: • Vegetables, fruit, food and nutrition waste and garden waste (Approximately 45%) • Paper, cardboard, wood (approximately 30%) • Plastics, mainly plastic packaging (approximately 5%) • Textile and leather (approximately 3%) • Diapers / sanitary napkin / incontinence products (approximately 2%) • Glass (approximately 6%) • Metals (approximately 3%) • Other waste including chemical waste, ceramic / porcelain / concrete (6%)

With the exception of glass, metal and the category of other waste, this invention can be used for all other categories mentioned.

Continued description of the invention (5 of 131: Before the pre-treatment of the waste, the glass, metal and other waste are removed. The methods and techniques required for the separation of these inert inorganic materials do not form part of this invention. Traces of these inorganic materials, which were not initially removed, are after the pre-treatment, i.e. before the fermentation, still passed through a 2 mesh screen or other device for separating the undissolved, non-disintegrated, unaffected solids. the substance to be fermented removed The sorted waste, free from metal, glass and other inert waste, is converted into a waste stream with particles no larger than 100 mm, preferably no larger than 75 mm and even better no larger than 50 mm before to expose the waste to the pretreatment The pretreatment consists of exposing the waste to sodium or potassium hydroxide, preferably onloog.

The pre-treatment takes place in a stirred vessel, a "fluid bed reactor" or a vessel in which a good contact between the sodium or potassium hydroxide and the waste is achieved so that the surface of the waste particles is regularly refreshed. The dry matter content in the lye / water / waste mixture is 15 to 70%, preferably 30 to 60% and even better 40 to 55%.

So much lye is added to the waste mixture that it corresponds to a pH of 10 to 16, preferably 12.7 to 14.4, and even better a pH that is associated with the total amount of plastic plus textile in the waste. At the start of pre-treatment, so much lye must be added to the waste that this corresponds to: 1. A pH of 13.4 if the total amount of plastic plus textile is less than 2.5% by weight, 2. A pH of 13.7 if this amount is 2.5 to 5%, 3. A pH of 14.0 if this amount is 5 to 10%, 4. A pH of 14.2 if this amount is 10 to 15%, 5. A pH of 14 3 if this amount is more than 15%.

The foregoing with the restriction that the amount of lye to be added always exceeds the amount that is required by stoichiometrically to saponify the polymers in the waste by at least 20%.

During the pre-treatment period, it must be prevented that the pH does not fall below a value of 10 by adding additional lye if necessary. During the pre-treatment, the pH may gradually decrease from the preferred starting value to a pH of 10 when 95% of the pre-treatment period has elapsed. The duration of the treatment is 25 to 100 minutes, preferably 40 to 80 minutes and more

Further description of the invention f6 from 131: better 55 to 60 minutes, at a temperature of 200 to 250 degrees Celsius, preferably 215 to 235 degrees and even better 223 to 225 degrees and a pressure of 10 to 50 bar, preferably 15 up to 30 bar and even better 20 to 25 bar. After the saponification of the waste mixture with lye under pressure, the mixture is neutralized with a strong acid, preferably with sulfuric acid, even better with another strong acid, such as nitric acid or phosphoric acid, if this is desired for the further course of the fermentation step. The final pH of the neutralized mixture is adjusted to a pH of 6.8 or a different value if the hydrolysis, sweetening and subsequent fermentation make this desirable. The temperature of the mixture to be fermented is brought to 20 to 70 degrees, all this again depending on the temperature which is desirable for a good course of the hydrolysis, subsequent sugaring and fermentation. At the same time, the dry matter content in the mixture to be fermented is lowered by adding water to 10 to 30%, or more specifically to a content that is desirable for the hydrolysis, sweetening and subsequent fermentation to proceed smoothly.

After removal of inert solid particles, a mixture that is suitable for anaerobic fermentation remains, consisting of: • dissolved substances such as alcohols, amino acids, carboxylic acids, carbohydrates and • finely dispersed material such as pulp particles, paper fibers, cellulose and fatty acids.

Normally, the anaerobic fermentation consists of the following steps which can take place simultaneously or successively: • Hydrolysis

Organic substances such as carbohydrates, for example cellulose, are converted into mono- and disaccharides by microorganisms.

• Acidogenesis

Organic substances are converted into smaller organic molecules, for example fatty acids.

• Acetogenesis

Organic molecules, such as fatty acids, are converted into small molecules such as acetic acid, hydrogen sulfide and carbon dioxide.

• Methanogenesis

Organic intermediates from the previous processes are converted into methane, carbon dioxide, etc.

Continued description of the invention f7 of 13V Explanation of the treatment with lye.

The pre-treatment of the waste as described in this patent application provides the following: • Harmlessization of all unwanted microorganisms (bacteria, fungi, viruses) and prion proteins. This is of particular importance for waste from places such as, for example, hospitals and airports, which are subject to strict waste management requirements in most countries to prevent the spread of infectious diseases. With this treatment, therefore, all microorganisms / prion proteins in the waste are destroyed. An outbreak of infectious diseases such as Creutzfeldt Jacob's disease is thereby prevented.

• Processing and disintegration of vegetables, garden waste, paper, cardboard and wood fractions. The lignocellulose structure of wood falls apart into lignin, hemicellulose and cellulose particles that are fermentable with the exception of lignin.

• Saponification of the polymers present in the waste, which are passed through! polycondensation has been prepared as a result of the saponification of the saponifiable groups present in the polymers (carbonate, ester or amide).

Practical application of this invention

This invention is important for all waste containing organic material, regardless of whether the origin of this organic material originates biologically or synthetically and which cannot be converted as such into anane by anaerobic fermentation.

Relevant types of waste with a substantial amount of organic material that cannot be sufficiently fermented without pre-treatment are: • Household waste mainly consists of plastic, textile, wood, paper, cardboard and food residues.

• Waste from the catering industry consisting mainly of foodstuffs, food residues, paper and plastic packaging.

• Waste from the paper and cardboard industry mainly consists of biomass, wood and plastic.

• Waste from the food and feed industry consisting mainly of biomass, plastic and cardboard.

Continued description of the invention (8 of 13): • Waste from the medical industry mainly consisting of chemicals, plastic and cardboard.

• Waste from agricultural activities, such as lignocellulose-containing residual products from crops, cardboard and plastic. • Waste from the plastic (packaging) industry mainly consisting of plastic and cardboard.

• Waste from the textile industry mainly consisting of fibers of a biological or synthetic origin, paper and cardboard.

Example 1:

In various countries, households sort their waste into "green" waste (fruit-food-flowers-vegetables-garden waste), paper and cardboard, glass, metal, chemical and other undefined waste.

This invention makes it possible to pre-treat the green waste together with paper and cardboard, sanitary waste (diapers and sanitary napkins), plastic and textile without further separation, after which the whole can be converted into biogas and compost by anaerobic fermentation. The efficiency of the production of biogas using this method will thereby increase considerably if the use of polymers for, for example, plastic (packaging) and textile is limited to the polycondensation polymers, preferably polyester, polyamide and the biopolymers.

The switch to these polymers in most cases does not impede the performance of the goods made from these polymers. For example, plastic food packaging made from polyethylene terephthalate (PET) often gives an equal or better performance compared to the packaging made from polyaddition polymers, such as polystyrene or polypropylene. As a result, food wrapped in plastic PET would qualify as green waste because it is fully recyclable, as described in this document.

It is the intention and expectation of the inventors that in the future mainly polymers will be used for textile and plastic production, which can be saponified after their economic life, via the method described in this patent. The energy content of these products, usually made from fossil fuels, is almost completely recovered. A huge advantage over other widely used ways of waste processing.

Continue description of the invention (9 of 13V

The following example illustrates the importance of this invention.

Waste consisting of food residues and PET plastic packaging with the following composition has been investigated: • Water 50% • Dry organic matter 48% o Dry organic substances from food 33% o Plastic PET 15% • Dry inorganic substance 2%

The waste, as described in this document, pre-treatment with caustic soda followed by anaerobic fermentation, yields 368 cubic meters of natural gas per tonne and therefore yields an efficiency of 87%. Compared with other methods of recovering energy from waste, this method yields a considerably higher return. The system costs for processing waste can therefore fall considerably.

Example 2:

The processing of the waste materials, as described in Example 1, makes it possible to produce energy from waste even in the most remote places. If desired, manure, sewage sludge, animal remains from slaughterhouses etc. can be added, both before and after pre-treatment, to the energy stored in the waste in the form of biogas (methane, mixed with small amounts of other gases such as carbon dioxide, nitrogen and hydrogen sulphide). ).

The biogas can be used to produce electricity or as a fuel for engines, heating and cooking. The capital investments, compared to incineration plants, for example, are relatively low in the light of the required average investment of 2,500,000 euros per 10,000 tons of annual capacity. Developing countries could benefit extra from this approach. Food packaging greatly contaminates the environment in these countries and this invention could prevent this. Even when the biogas is used for the production of electricity, the yield is significantly higher compared to incineration. Ten thousand tons of waste, with the composition given in example 1, would generate 8 GWh of electrical energy. The same waste burned in an incineration plant would yield only 3.3 GWh for comparison. In addition, the net carbon dioxide emissions for combustion are 892 kg and for fermentation only 509 kg per MWh.

Continue description of the invention (10 of 13):

Patents that interface with this invention

EP 2022818 A

Nakamura Koichi [JP], February 11, 2009, process for the decomposition and identification of synthetic resins with ester-linkage structures.

The aforementioned patent claims the hvdrolvse of specific synthetic plastics, n.l. those plastics containing ester groups by using steam at a temperature equal to or lower than the melting temperature of the plastic for the purpose of recovering the monomers from which the plastic is composed.

This patent application concerns the saponification of organic material in waste, with a widely divergent composition, with sodium hydroxide which is a must! has biogas to produce.

WO 2007/036 795 A

Elsam Engineering AS [DK] et. al., April 5, 2007, non-pressurized pre-treatment, enzymatic hydrolysis and fermentation of waste fractions.

The aforementioned patent claims the pre-treatment of the organic material in waste with steam of 60 to 110 degrees for 0 to 120 minutes.

This patent application claims the saponification of organic material in waste, with a widely varying composition, with sodium hydroxide at many higher temperatures and pressures.

• JP 2005-330 211 A

Univ Toyohashi Technology et. al., December 2, 2005, method for hydrolyzing biodegradable polyester into monomer, and apparatus for treating biodegradable polyester.

The aforementioned patent claims the hvdrolvse of polvlactate. in the presence of general purpose plastic, with water of 160 to 200 degrees for the purpose of recovering the monomeric lactic acid.

This patent application claims the saponification of organic material in waste, with a widely divergent composition, with sodium hydroxide solution at higher temperatures and pressures with the aim of producing biogas.

Continued description of the invention (11 of 13)

• JP 2005-095 729 A

Kobe Steel Ltd et. al., April 14, 2005, treatment method and treatment apparatus for organic type waste containing biodegradable plastic.

The aforementioned patent claims the hvdrolvse of biodegradable plastics with water.

This patent application claims the saponification of organic material in waste, with a widely divergent composition, with sodium hydroxide in cattle! higher temperatures and pressures.

EP 0 810 041 A

Ebara Corp. [JP], December 3, 1997, method of converting organic wastes to valuable resources.

The aforementioned patent claims the pre-treatment of waste, prior to fermentation, which consists of a mechanical pre-treatment of the waste. This patent application claims a chemical pre-treatment of the waste with soda lye.

EP 0 646 620 A

Hoechst AG [DE], April 5, 1995, process for the valorization of waste material containing cellulosic fibers and synthetic polymer fibers.

The aforementioned patent claims the hvdroivse of cellulose fibers by micro-organisms in a composition of cellulose and synthetic yarns (biological pre-treatment).

This patent application claims the saponification of organic material in waste, with a widely divergent composition, with sodium hydroxide solution at much higher temperatures and pressures (chemical pre-treatment).

Continue description of the invention (12 of 13Y.

Distinctive character of this patent

Methods for recovering the energy content of organic waste are: • Gasification

Methods for the production of biofuels by gasification: 1. direct heating of the solid waste materials or 2. with metal salts dissolved in water at temperatures between 250 and 1000 degrees or 3. via a hydrothermal treatment.

The organic material pyrolyses at these high temperatures into low molecular flammable substances that are separated from the waste by distillation or other separation techniques.

This method is costly and the application of gasification is limited to organic waste fractions for which there are no other alternatives such as, for example, thermosetS (epoxides, etc.). However, in most cases, normal combustion is cheaper and more effective.

• Incineration

The waste is incinerated in an incineration plant and the heat is used for the production of steam. The steam is used to produce electricity. The yield of this process is mediocre.

• Anaerobic fermentation 1. Direct fermentation of biomass without pre-treatment.

The biomass is hydrolysed, sugared and fermented into biofuel.

2. Anaerobic fermentation by, after pre-treatment, converting the organic waste into a substrate that is suitable for direct fermentation.

• Well-known pre-treatment methods are: • Treatment with super critical steam or • Treatment with diluted sulfuric acid or • Mechanical treatment possibly in combination with steam

This patent application is an addition to the known pre-treatment methods because it makes it unnecessary to separate the organic fraction in the waste into the various categories such as plastic, wood, paper, cardboard, textile, vegetable, fruit and garden waste. The pre-treatment of the waste described in this patent application, consisting of, for example, the aforementioned categories, makes this waste suitable for anaerobic fermentation without further separation. The fact that plastic, wood, paper, cardboard and textiles are mixed with biomass such as food, grass,

Continued description of the invention (13 of 13): manure, vegetables, fruit, flower and garden waste has no influence on the process.

The separation of waste is cost-increasing and is a growing concern for the public, because the possibility of a proper implementation of waste separation is often not feasible. With this invention, it is no longer necessary for households and others to separate their waste, but with the exception of a very small amount of chemical and pharmaceutical waste.

The separation of the inorganic substances in the waste is easier and at relatively low costs to carry out in the waste processing installations. A positive side effect of this invention could be that the replacement of metal and glass with plastic, for example for packaging purposes, will proceed faster. The packaging of, for example, food or wine in glass can be called wastage because better alternatives such as polyethylene terephthalate exist. For economic and environmental reasons, the reduction in the use of glass and metal is favorable.

Claims (4)

A universally applicable treatment method in which the organic fraction in waste, with a very strong base under high pressure and at high temperature, is processed into a substance that can then be converted into biogas and compost by means of anaerobic fermentation. 2. The method of claim 1 wherein the organic fraction in the waste consists of a mixture of plastics and / or textile and paper and / or cardboard and / or wood and / or biomass and / or undefined waste originating from one or more from the sources below: a. Households, whose organic waste usually consists of food, vegetables, fruit and garden waste, plastic packaging, paper and cardboard. b. Catering sector, whose waste mostly consists of food, vegetables, fruit and garden waste, plastic packaging, paper and cardboard. c. Sectors, such as the catering in hospitals, nursing homes, airplanes, trains, boats and airports, which are subject to strict rules for waste processing that serve to prevent the spread of infectious diseases. d. Agriculture, horticulture, animal husbandry, flowers and fruit related activities, of which the organic waste often consists of plant remains that remain after processing of the harvest, waste from vegetables, fruit and flowers, waste from animal feed, paper, cardboard and plastic. e. Industry such as the food and feed industry, paper and cardboard industry, slaughterhouses, wood processing companies, the textile and plastic industry plus industries such as trade and logistics, the medical and pharmaceutical industry, whose waste may consist of plastics, textiles, paper, cardboard, animal waste, food and wood. f. Retail / small and medium-sized business, whose waste is mostly paper, plastic, textile, wood and cardboard. g. Public sector, whose waste is mainly plastic, paper and cardboard. Continued cohclusions / claims (2 of 2 ^ 2. Conclusions / claims (1 of 2j) Conclude that this invention consists of: 3. The method of claims 1 and 2 whereby the treatment is carried out with sodium or potassium hydroxide (lye) and in which: a. The solids in the waste prior to pre-treatment are reduced to a particle of no more than 100 millimeters, b. the waste is mixed with sodium or potassium hydroxide in water, c. the dry matter content is 15 to 70 percent by weight, d. the pH is 10 to 16, e. the amount of the lye to be added is at least 20% higher than the amount that is required stoichiometrically to saponify the polymers in the waste, f. the temperature during the treatment is 200 to 250 degrees Celsius, g. the pressure is 10 to 50 bar, h. the duration of the pre-treatment is 25 to 100 minutes, i. the pre-treatment is carried out in a vessel equipped such that the contact surface of the solid particles with the liquid is continuously refreshed. 4. The method according to claims 1-3 whereby after treatment a sterile and prion-protein-free mixture is obtained from mainly organic substances which can subsequently be converted by anaerobic fermentation into biogas and a high-quality compost.