KR20170088176A - Anaerobic digestion system of organic waste through the thermal hydrolysis - Google Patents

Abstract

The present invention relates to an organic waste anaerobic digestion system including thermal hydrolysis, and more particularly, to a system for anaerobic digestion of organic waste by maximizing the anaerobic digestion efficiency of organic waste through high- And to provide a method and system for organic waste anaerobic digestion including thermal hydrolysis.
Also, waste heat and biogas generated in the biogas power generation process may be used as a thermal hydrolysis solubilization device, a sludge drying device, or a thermal hydrolysis solubilizing device and a fuel for a sludge drying device in an anaerobic digestion system including thermal hydrolysis of the present invention As it is recycled, the energy independence rate can be more than 50%.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic waste anaerobic digestion system including thermal hydrolysis,

The present invention relates to an anaerobic digestion system for organic wastes, and more particularly to an organic waste anaerobic digestion system including thermal hydrolysis.

The amount of organic waste including sewage sludge, manure, animal wastes, livestock waste, and industrial wastes such as industrial wastes is expected to increase steadily in the future due to improvement in living standards, population increase, new town development, and increase in income . As of the end of 2013, organic wastes generated from the whole country are 210,450 ton / day, which is the highest with 126,264 ton / day, 60% of total livestock manure, 62,010 ton / day (29.5% Food waste is 12,501 tons / day (5.9%) and sewage sludge is 9,675 tons / day (4.6%).

In addition, according to the present invention, various problems may occur in the treatment of organic wastes. Most of the food wastes are processed by recycling methods such as feed conversion and composting. However, by 2012, about 50% of the generated wastewater (including dry condensed water) generated in the treatment process was treated through ocean discharge. In the case of manure septic tank sludge, more than 95% of the manure sludge sludge is treated directly at the sewage treatment plant or at the sewage treatment plant after the first treatment. In the case of sewage sludge, it is used as an auxiliary fuel for coal-fired power plant and cement kiln after treatment with dry fuel conversion, carbonization and composting, or is recycled by other methods. In addition, in the case of livestock manure, most of them are difficult to treat, and pollution is increasing in nearby water system due to proper treatment.

Meanwhile, marine dumping, which is widely used in the treatment of organic wastes, is being banned from January 1, 2013 due to amendments to international conventions such as the London Convention and the 96th Protocol and the Marine Environment Management Act. As a result, a treatment method through anaerobic digestion has been attracting attention as an environmental, economical and efficient treatment method of high concentration organic wastes.

The main purpose of organic waste disposal is to reduce and stabilize organic waste digestion sludge. In addition, anaerobic digestion is a suitable treatment method for the reduction and stabilization of digestion sludge such as elimination of odor, reduction of pathogens and volume reduction of organic waste digestion sludge. In addition, since it is possible to recover energy by methane gas generated as a byproduct of anaerobic digestion, it can be used as another energy source, and thus it is an environmentally friendly process which can be economically secured. Despite these possibilities, however, practical applications have not been extended due to problems such as long residence time, low treatment efficiency, unstable process and bad odor, and they have been used limitedly. Therefore, it is necessary to study various process improvement and improvement of treatment efficiency with the aim of solving these problems.

On the other hand, the anaerobic digestion process can be divided into three stages: hydrolysis, acid production, and methane production. Among them, the hydrolysis step is a step of limiting the entire processing speed. In the hydrolysis step, organic matter is surrounded by cell membranes and cell walls. Therefore, anaerobic microorganisms decompose organic matter for a long time, which is a rate limiting step in the whole reaction. As a method of controlling the rate limiting step, there is a method of pretreatment through mechanical and chemical treatment before anaerobic digestion.

In this regard, Korean Patent Laid-Open No. 2003-0042866 discloses an anaerobic digestion method for organic wastes which is hydrolyzed by microwave treatment. However, microwave pretreatment has disadvantages such as deterioration of the anaerobic digestion efficiency by destroying the organic substances usable in the anaerobic digestion stage during the pretreatment.

In another example, Korean Patent Laid-Open Publication No. 2015-0048991 discloses a method for treating organic wastes including a step of hydrolyzing through ozone treatment or high temperature steam treatment. However, in the case of ozone treatment, an ozone dosage corresponding to 15 to 20% of the solids weight is required. In addition, there is a problem in that it is not economical due to excessive equipment cost and electricity cost for generating ozone, and oxygen cost as a raw material, and a pH drop phenomenon is conspicuous, so that separate medicine administration is indispensably required. In addition, at the time of the ozone treatment or the high-temperature steam treatment, bubbles are generated due to the reaction with organic wastes, thus requiring a foam eliminator and a foam removal process. In addition, in spite of the pretreatment, the anaerobic digestion tank and the anaerobic digestion stage have to be added one more step for fermentation and decomposition of the organic matter having low biodegradability, and thus the anaerobic digestion step must be carried out in two stages, which is not economical.

Meanwhile, the sewage treatment plant, which is one of the organic waste treatment facilities operated in Korea, consumes a large amount of energy in the collection and treatment of sewage. In addition, there is almost no energy source capable of self-supporting energy consumption compared to high energy consumption, and it is urgent to secure an energy source capable of self-supporting energy in the sewage treatment plant. In fact, according to the results of the 2010 survey, the energy independence rate at the national sewage treatment plant (the "energy independence rate" is the ratio of the amount of electricity generated through the production of renewable energy to the total annual energy consumption at the sewage treatment plant, Only 0.8%. As a representative cause of such a situation, the organic waste can not be sufficiently decomposed at the anaerobic digestion stage, and the amount of biogas that can be utilized as energy can be reduced. In addition, this is because the anaerobic digestion pretreatment concept is not equipped with the solubilization facility, and the anaerobic digestion tank can not sufficiently decompose the organic matter. Therefore, the biogas produced is simply incinerated or used for small- and medium-sized boilers, so the rate of energy independence is very low. In addition, consideration is given to the RFS (Renewable Fuel Standard) and the Renewable Portfolio Standard (RPS), which have been in effect since January 1, 2012, since the end of July 2015. , There is a need for measures to increase the energy independence rate.

Korean Patent Publication No. 2003-0042866 (published on June 2, 2003) Korean Patent Publication No. 2015-0048991 (published on May 5, 2015)

Therefore, there is a desperate need to develop a system and method for efficiently anaerobic digesting vast amounts of organic wastes.

In addition, it is necessary to develop an organic waste anaerobic digestion system and method capable of increasing the anaerobic digestion efficiency and increasing the biogas generation amount.

Furthermore, from an environmental point of view, environmental pollution that may occur when organic wastes are treated insufficiently should be prevented.

There is also a need for measures to increase the energy independence rate in the organic waste anaerobic digestion system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an organic waste anaerobic digestion system including thermal hydrolysis. In addition, it is another object of the present invention to provide a method for anaerobic digestion of organic wastes including thermal hydrolysis.

It is also intended to shorten the anaerobic digestion time of organic wastes and to increase the anaerobic digestion efficiency through the pretreatment of thermal hydrolysis, thereby maximizing the biogas generation amount.

Another object of the present invention is to increase the energy independence rate in the organic waste anaerobic digestion system by effectively recycling the energy generated in the organic waste anaerobic digestion process by various methods.

In order to achieve the above-mentioned object,

A reservoir for storing organic waste;

The organic waste supplied from the storage tank is heated at a temperature of 160 to 200 ° C, preferably 180 to 200 ° C, more preferably 190 to 200 ° C and 5 to 10 bar, preferably 6 to 10 bar, more preferably 7 to 10 bar a thermohydrolysis solubilizer for thermally hydrolyzing in a bar, destroying the cell walls of the organic material and decomposing the biopolymer;

A medium-temperature single-phase digestion tank for anaerobically digesting the organic waste having undergone the thermal hydrolysis and solubilization to produce a gaseous product containing biogas and digested sludge;

A dehydrator for dehydrating the digested sludge produced through the anaerobic digestion to produce dehydrated sludge;

A sludge drying device for drying the dehydrated sludge dewatered by the dehydrator to produce a dried material;

A biogas refining facility for separating the biogas from the gaseous products produced through the anaerobic digestion; And

The present invention provides an organic waste anaerobic digestion system comprising an energy recycling facility using the dried material, biogas, or dried material and biogas as a fuel.

In addition, the organic waste anaerobic digestion system of the present invention may further include a cooler for lowering the temperature of the organic waste prior to the addition to the medium-temperature single-phase digestion tank.

The organic waste anaerobic digestion system of the present invention may further include a digested sludge storage tank for storing digested sludge discharged from the medium-temperature single-phase digestion tank.

In addition, the organic waste anaerobic digestion system of the present invention may further include a reflux water treatment device for removing organic substances and phosphorus in the desorption filtrate generated in the dehydrator.

In addition, the organic waste may be selected from the group consisting of sewage sludge, food waste, manure sludge, and mixtures thereof.

The manure sludge may also be manure sludge, livestock manure sludge or human manure sludge and livestock manure sludge.

Further, the sewage sludge may be transferred to the storage tank after dewatering.

In addition, the food waste may be transported to the storage tank after crushing and sorting.

Also, the manure sludge can be transferred to the storage tank after the removal of dirt and dehydration.

The water content of the organic waste transferred to the storage tank may be 75 to 90%, preferably 80 to 85%, more preferably 82 to 84% after dewatering.

In addition, the above-mentioned sorting can pass only particles having a particle diameter of 10 mm, preferably 7 mm, more preferably 5 mm or less, but is not limited thereto.

Further, the removal of the impurities may be 95 to 100%, preferably 97 to 100%.

The moisture content of the dried product after drying may be 1 to 10%, preferably 4 to 9%, more preferably 6 to 8%.

Also, the heavy-temperature single-phase digestion tank may be equipped with a mechanical forced stirring apparatus.

Further, the heavy-temperature single-phase digestion tank may include a scum removing device for removing scum.

In addition, the mesophilic single-phase digestion tank may have a cyclone below the sediment to transfer the microorganisms to the digester.

Also, the heavy-temperature single-phase digester may be operated at 35 to 40 DEG C, preferably at 37 to 40 DEG C, and more preferably at 38 to 39 DEG C.

In addition, the residence time in the medium-temperature single-phase digestion tank may be 5 to 30 days, preferably 7 to 25 days, more preferably 10 to 20 days.

In addition, the biogas can be supplied to a gas generator to produce electricity, and the waste heat generated during the power generation process can be recycled as a heat source for a thermal hydrolysis solubilizer, a sludge drying unit, a thermal hydrolysis solubilizer, and a sludge drying unit .

In addition, the biogas can be recycled as a fuel for a thermal hydrolysis solubilizer, a sludge dryer, or a thermal hydrolysis solubilizer and a sludge dryer.

In addition, the dried material can be recycled as an auxiliary fuel for a thermal power plant, a cement kiln, or a thermal power plant and a cement kiln.

On the other hand, the present invention provides (A) a storage step for storing organic wastes; (B) the organic waste is heated at a temperature of 160 to 200 DEG C, preferably 180 to 200 DEG C, more preferably 190 to 200 DEG C and 5 to 10 bar, preferably 6 to 10 bar, more preferably 7 to 10 bar A thermal hydrolysis and solubilization step of destroying the cell wall of the organic material and decomposing the biopolymer; (C) an anaerobic digestion step of anaerobically digesting the organic waste after the hydrolysis and solubilization step to produce a gas product containing biogas and digested sludge; (D) a dehydrating step of dehydrating the digested sludge produced through the anaerobic digestion to produce dehydrated sludge; (E) drying the dehydrated sludge to produce a dried product; (F) a biogas purification step of separating the biogas from the gaseous products produced through the anaerobic digestion; And (G) an energy recycling step of using the dried material, the biogas, or the dried material and the biogas as a fuel, in an organic waste anaerobic digestion method.

The organic waste anaerobic digestion method of the present invention may further include a cooling step of lowering the temperature of the organic waste after the hydrolysis and solubilization step before the anaerobic digestion step.

In addition, the organic waste anaerobic digestion method of the present invention may further include a digestion sludge storage step for storing the digested sludge produced through the anaerobic digestion prior to the dehydration step.

Further, the organic waste anaerobic digestion method of the present invention may further include a reflux water treatment step of removing organic substances and phosphorus in the desorption filtrate, which is generated upon dehydration of the digested sludge produced through the anaerobic digestion.

In addition, the organic waste may be selected from the group consisting of sewage sludge, food waste, manure sludge, and mixtures thereof, but is not limited thereto.

In addition, the organic waste anaerobic digestion method of the present invention may further include dehydrating the sewage sludge prior to the storage step.

Further, prior to said retention step, said food waste may further comprise a step of crushing and screening.

Further, prior to the storage step, the manure sludge may further comprise a step of removing contaminants and dewatering.

In addition, the water content after dehydration of the organic waste before the storage step may be 75 to 90%, preferably 80 to 85%, more preferably 82 to 84%.

In addition, the above-mentioned sorting can pass only particles having a particle diameter of 10 mm, preferably 7 mm, more preferably 5 mm or less, but is not limited thereto.

In addition, the removal rate of the impurities may be 95 to 100%, preferably 97 to 100%.

In addition, the water content of the dried product produced in the drying step may be 1 to 10%, preferably 4 to 9%, more preferably 6 to 8%.

In addition, the anaerobic digestion step may be carried out at 35 to 40 DEG C, preferably 37 to 40 DEG C, more preferably 38 to 39 DEG C.

In addition, the anaerobic digestion step may be performed for 5 to 30 days, preferably 7 to 25 days, more preferably 10 to 20 days.

Also, in the energy recycling step, the biogas is supplied to the gas generator to produce electricity, and the waste heat generated in the power generation process is supplied to the gas generator through the heat hydrolysis and solubilization step, the sludge drying step, Can be recycled.

Also, in the energy recycling step, the biogas can be recycled as a fuel for the hydrolysis and solubilization step, the sludge drying step, or the hydrolysis and solubilization step and the sludge drying step.

In addition, in the energy recycling step, the dried material can be recycled as an auxiliary fuel for a thermal power plant, a cement kiln, or a thermal power plant and a cement kiln.

The organic waste anaerobic digestion system including the above-mentioned thermo-hydrolysis of the present invention can be applied to a medium-temperature single-phase digestion tank in which anaerobic digestion is performed in an optimal state for solubilization and decomposition of organic substances by solubilization by thermal hydrolysis using high temperature and high pressure There is an effect that it can be injected.

Further, the residence time of the organic waste in the medium-temperature single-phase digestion tank can be shortened, and the medium-temperature single-phase digestion tank can be stably operated.

In addition, although the residence time is shortened, since the substrate is stably anaerobically digested and the anaerobic digestion efficiency is increased, stability and economical efficiency can be secured.

In addition, since stable anaerobic digestion is performed and efficiency is increased as described above, there is an effect that the amount of biogas generated during anaerobic digestion can be maximized.

In addition, by performing pretreatment according to the type and characteristics of the organic waste, the thermal hydrolysis efficiency and the anaerobic digestion efficiency can be increased, and the various organic waste can be effectively anaerobically digested.

In addition, compared with the conventional anaerobic digestion, the digested sludge generated through anaerobic digestion of the organic waste according to the present invention is excellent in dewaterability and can reduce the amount of the drug used, and the dewatered sludge has a remarkably reduced odor, It is effective.

In addition, the dried material can be recycled as an auxiliary fuel, and the biogas generated in the anaerobic digestion process can be recycled directly or through power generation, such as in-house power and LNG alternative fuel, thereby maximizing energy recycling efficiency.

Also, waste heat and biogas generated in the biogas power generation process may be used as a thermal hydrolysis solubilization device, a sludge drying device, or a thermal hydrolysis solubilizing device and a fuel for a sludge drying device in an anaerobic digestion system including thermal hydrolysis of the present invention As it is recycled, the energy independence rate can be more than 50%.

In addition, it is possible to respond to the RFS (Renewable Fuel Standard) system and the Renewable Portfolio Standard (RPS) system, and to reduce greenhouse gas emissions and reduce the use of fossil energy. have.

1 is a block diagram showing a configuration of an organic waste anaerobic digestion system according to an embodiment of the present invention.
2 is a flowchart showing an embodiment of the anaerobic digestion method of the organic waste according to the present invention.
3 is a graph showing the digestion efficiency characteristics according to the first embodiment of the present invention.
4 is a graph showing gas generation rate characteristics according to Example 1 of the present invention.
5 is a graph showing the digestion efficiency characteristics according to Comparative Example 1 of the present invention.
6 is a graph showing gas generation rate characteristics according to Comparative Example 1 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the following description, numerous specific details, such as specific elements, are set forth in order to provide a thorough understanding of the present invention, and it is to be understood that the present invention may be practiced without these specific details, It will be obvious to those who have knowledge of. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

First, some of the terms used in this specification are defined.

In the present specification, the term biopolymer includes proteins, polysaccharides, nucleic acids, fibrin, etc. as generic terms of the polymeric compounds produced by the organism.

In the present specification, the term "reflux water" refers to a denitrification tank for anaerobic digestion of organic waste, a desolvation filtrate or dehydration filtrate resulting from the dehydrator 800, and the like.

In the present specification, "scum" is a substance which occurs mainly in aeration tank and sedimentation tank such as a water treatment plant, a wastewater treatment plant, a paddy field treatment plant, and a gas-liquid boundary layer of anaerobic digestion tank, and obstructs anaerobic digestion operation and causes problems.

In this specification, VS is an abbreviation of volatile solids and is an organic component that is volatilized when total solids are ignited at 600 ° C.

In the present specification, the VS reduction rate is a measure for determining the reduction ratio of the organic component in the digested sludge, which is also known as the ignition loss, as a result of anaerobic digestion.

As used herein, substrate refers to organic wastes in the system of the present invention and is preferably used as a term to refer to organic wastes that are put into each facility or apparatus in the system.

As used herein, COD is a chemical oxygen demand amount, which indicates an oxygen demand amount for oxidizing a chemically oxidizable organic matter, and is a measure for measuring the organic matter content in organic wastes.

In the present specification, SCOD refers to soluble COD in the COD.

In the present specification, HRT is hydraulic retention time (HRT), which indicates the hydraulic average residence time and refers to the tank capacity / inflow flow rate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a block diagram showing a configuration of an organic waste anaerobic digestion system according to an embodiment of the present invention.

As shown in FIG. 1, the present invention includes a storage tank 400 for storing organic wastes, an organic waste supplied from the storage tank 400 at 160 to 200 ° C, preferably 180 to 200 ° C, more preferably 190 To 500 deg. C and 5 to 10 bar, preferably 6 to 10 bar, more preferably 7 to 10 bar to decompose the cell wall of the organic material and decompose the biopolymer. The thermo-hydrolysis solubilizer 500 )Wow,

A middle-temperature single-phase digestion tank 600 for anaerobic digesting organic wastes subjected to the thermo-hydrolysis and solubilization to produce a gaseous product containing biogas and digested sludge, a deodorization unit for dehydrating the digested sludge produced through the anaerobic digestion to produce dehydrated sludge A sludge drying device 900 for drying the dehydrated sludge dehydrated by the dehydrator 800 to produce a dried product,

A biogas refining facility 610 for separating the biogas from the gaseous products generated through the anaerobic digestion and an energy recycling facility 620 for using the dried material, biogas or dried material and biogas as fuel, It is an object of the present invention to provide an organic waste anaerobic digestion system.

In the organic waste anaerobic digestion system of the present invention, the organic waste is introduced into the thermohydrolysis and solubilization apparatus 500 via the storage tank 400 before being introduced into the mesophase single-phase digestion tank 600 which is fully anaerobically digested. The organic waste introduced into the thermohydrolysis and decomposition apparatus 500 is heated at a temperature of 160 to 200 ° C, preferably 180 to 200 ° C, more preferably 190 to 200 ° C, and 5 to 10 bar, preferably 6 to 10 bar Preferably 7 to 10 bar. This is an effective range in which the cell wall of the organic material in the organic waste is destroyed and the biopolymer is decomposed, and the biodegradable materials other than the cell wall may be destroyed. In addition, hydrolysis efficiency is increased because heat and pressure treatment are performed at the same time. Also, in this process, organic substances having a complicated structure are effectively solubilized by solubilizing materials such as monomers and oligomers, which enables faster and more efficient anaerobic digestion. Particularly, in the case of solid wastes such as organic wastes, this hydrolysis step is a very important step in the process efficiency and treatment time of the whole anaerobic digestion system.

The organic waste that has been solubilized through the thermal hydrolysis and solubilizing apparatus 500 flows into the medium-temperature single-phase digestion tank 600. Here, anaerobic digestion of the organic waste introduced into the medium-temperature single-phase digestion tank 600 is performed, thereby producing a gaseous product containing biogas. At this time, organic wastes introduced into the medium-temperature single-phase digestion tank 600 are thermally hydrolyzed and solubilized, so that the efficiency of anaerobic digestion, which reacts with the substrate as a substrate, is increased, and the production efficiency of biogas that can be produced in this process is also increased . Compared to a general anaerobic digestion system, anaerobic digestion in the organic waste anaerobic digestion system of the present invention enables the biogas generation to be increased by more than 40%, and thus energy for recycling is increased, which is much more economical in terms of energy recycling. In addition, the treatment time is shortened due to the increase in the anaerobic digestion efficiency, and the time for organic wastes to stay in the medium-temperature single-phase digestion tank 600 can be shortened. In addition, the energy required for anaerobic digestion is also reduced by increasing the anaerobic digestion efficiency and shortening the residence time.

In addition, the volume of the medium-temperature single-phase digestion tank 600 in the anaerobic digestion system of the present invention can be reduced to about half that of the anaerobic digestion system of a general anaerobic digestion system. This makes it easier to install and manage the facility, which makes it possible to operate a more stable digester and reduce operating energy. In addition, the VS reduction rate is about 40% in the anaerobic digestion system in the general anaerobic digestion system, while the VS reduction rate is more than 55% in the anaerobic digestion system in the organic waste anaerobic digestion system including the thermal hydrolysis of the present invention, It enables operational and operational energy savings. In addition, the reduction of the digestion tank volume and the VS reduction rate as described above leads to an increase in the anaerobic digestion efficiency and the biogas generation amount. In particular, the biogas generation amount can be increased by 40% or more as compared with a general anaerobic digestion system.

In addition, the organic waste anaerobic digestion system of the present invention further includes a cooler 510 for lowering the temperature of the organic waste before the organic waste passed through the thermal hydrolysis and solubilizing apparatus 500 is introduced into the medium-temperature single-phase digestion tank 600 . The thermally hydrolyzed organic waste discharged from the cooler 510 is cooled to a temperature optimum for microbial growth in the mesophase single-phase digester 600 where anaerobic digestion takes place, for example, at a temperature of about 38 to 39 ° C. Since the cooled organic waste is fed to the medium-temperature single-phase digestion tank 600, the medium-temperature single-phase digestion tank 600 can be operated stably, which may lead to an increase in the anaerobic digestion efficiency and maximization of the biogas production. In general anaerobic digestion system, warming and warming energy are needed to keep the digester at about 35 ℃ in case of mid - temperature digestion. Therefore, compared to a general anaerobic digestion system, the organic waste anaerobic digestion system of the present invention does not require a separate digestion tank warming, so that it is possible to save energy required for heating and maintaining the digestion tank.

Also, the organic waste anaerobic digestion system of the present invention may further include a digester sludge storage tank 700 for storing digested sludge discharged from the medium-temperature single-phase digestion tank 600. The digested sludge storage tank 700 temporarily stores extinguishing sludge discharged from the mid-temperature single-phase digestion tank 600 and the organic waste having passed through the extinguishing sludge storage tank 700 is dehydrated after being introduced into the dehydrator 800 to generate dehydrated sludge . In the general anaerobic digestion system, the water content of the dehydrated sludge is about 80%, whereas in the organic waste anaerobic digestion system of the present invention, the dehydration due to thermal hydrolysis is very high and the dehydration sludge water content can be maintained at 70% or less. Therefore, it is possible to reduce the amount of dehydrated sludge generated and reduce the energy consumption required for treating the dehydrated sludge having a low water content even in the subsequent drying step, which is economical.

In addition, the organic waste anaerobic digestion system of the present invention may further include a reflux water treatment device 810 for removing organic substances and phosphorus in the desorption filtrate generated in the dehydrator 800. Reduction and stabilization of digested sludge in anaerobic digestion system is one of the main purposes of anaerobic digestion. Therefore, it is necessary to separate and reduce the desorption filtrate, which is the moisture of the digested sludge, through the dehydrator 800, and to remove the organic substances and phosphorus in the desorption filtrate through the reflux water treatment device 810.

In addition, the digested sludge generated through the anaerobic digestion is dehydrated in the dehydrator 800, and the generated dehydrated sludge is transferred to the sludge drying device 900 and dried to produce a dried product.

The moisture content of the dried product after drying may be 1 to 10%, preferably 4 to 9%, more preferably 6 to 8%. This is a range in which the generation of odor is effectively prevented due to sufficient dehydration and drying of the digested sludge, and the volume is reduced to facilitate handling. In addition, since the water content is low, it is difficult to decay when discharged, and environmental pollution can be prevented. Further, since the dried material can be used as an auxiliary fuel for a thermal power plant or a cement kiln during the treatment, the entire system can be made more economical. In addition, in the organic waste anaerobic digestion system of the present invention, since the cell wall of the organic material is destroyed by heat hydrolysis and the biopolymer is decomposed, the dried material having a lower water content can be obtained. In other words, since hydrolysis and solubilization of substances including binding water such as cells and polymers in organic waste are reduced to decrease the number of binding, the water removal efficiency can be further increased.

In addition, the dried material can be recycled as an auxiliary fuel for a thermal power plant, a cement kiln, or a thermal power plant and a cement kiln. Further, the energy independence rate of the organic waste anaerobic digestion system of the present invention can be further increased and the amount of fossil energy consumption can be reduced.

Meanwhile, the organic waste may be selected from the group consisting of sewage sludge, food waste, manure sludge, and mixtures thereof.

The manure sludge may also be manure sludge, livestock manure sludge or human manure sludge and livestock manure sludge.

As shown in FIG. 1, the organic waste anaerobic digestion system of the present invention may include an apparatus for pre-treating organic wastes such as sewage sludge, food waste, and manure sludge before they are introduced into the storage tank 400.

First, the sewage sludge can be transferred to the storage tank 400 after dewatering. Generally, the sewage sludge is concentrated in the concentration tank of the sewage treatment plant and supplied to the anaerobic digestion system according to the present invention. Before being transferred to the storage tank 400, the waste water sludge is first dehydrated through the sewage sludge dewatering device 110, 400, respectively.

Further, the food waste may be transported to the storage tank 400 after crushing and sorting.

Also, the manure sludge can be transferred to the storage tank 400 after the removal of the impurities and the dewatering. As each organic waste is subjected to the pretreatment suitable for the characteristics of each substrate as described above, mixing of the organic waste and storage in the storage tank 400 becomes easier. Further, it can be further stabilized as a substrate to be fed into the thermohydrolysis and solubilizing apparatus 500 through the storage tank 400, leading to a higher efficiency of thermo-hydrolysis and solubilization.

The water content after dehydration may be 75 to 90%, preferably 80 to 85%, more preferably 82 to 84%. By dehydrating to the above-mentioned range, the volume of the total organic waste to be treated is remarkably reduced, and the volume of the storage tank 400 can be reduced, and handling is facilitated. In addition, since the water content of the organic wastes is also reduced, the sludge generated after the anaerobic digestion of the organic wastes can be reduced and the energy required for drying the wastes is also reduced.

The food wastes are selected so as to pass only particles having a particle diameter of 10 mm, preferably 7 mm, and more preferably 5 mm or less after the crushing process generally performed in the technical field of the present invention, It can be transferred to the storage tank 400 in a state where 95% or more, preferably 97% or more of various foreign substances such as vinyl, iron, plastic, and bone is removed. In addition, since the particle size is reduced, the volume of the total organic waste is significantly reduced, and the volume of the storage tank 400 can be reduced, and handling is facilitated.

In the case of the manure sludge, foreign matter is removed through the impregnation processor 310 for sorting out foreign matter. As described above, since the impurities are removed, the dewatering process through the manure sludge dewatering unit 320 after the removal of the contaminants can be made easier and the dewatering efficiency can be further increased.

Also, the medium-temperature single-phase digestion tank 600 of the organic waste anaerobic digestion system of the present invention may be equipped with a mechanical forced stirring apparatus. The mechanical forced stirring device allows the organic waste in the mid-temperature single-phase digestion tank 600 to remain in complete mixing with the anaerobic digestive microorganisms. In addition, it eliminates abnormal foaming of organic waste and improves scum removal efficiency.

The medium-temperature single-phase digestion tank 600 may include a scum removing device for removing scum. The scum removing device can be positioned above the mesophase single-phase digestion tank 600 and serves to suppress and remove scum. Accordingly, not only can the scum layer be removed more efficiently early, but also the biogas partial pressure in the mid-temperature single-phase digestion tank 600 is lowered through the smooth discharge of the generated biogas to reduce the influence of the harmful gas.

The medium-temperature single-phase digestion tank 600 may have a cyclone below the sediment and transfer the microorganisms to the digester. This is because the organic waste in the medium-temperature single phase digester 600 Periodically removes sediments from a foreign substance contained in a trace amount, and returns the microorganisms, which may be lost during the removal process, to the medium-temperature single-phase digestion tank 600. Thus, the anaerobic digestion efficiency can be kept constant, stabilizing the entire continuous system and increasing the efficiency of the system.

Also, the heavy-temperature single-phase digestion tank 600 can be operated at 35 to 40 DEG C, preferably 37 to 40 DEG C, and more preferably 38 to 39 DEG C. Since the temperature of the organic waste supplied to the heavy-temperature single-phase digestion tank 600 is maintained at the temperature within the above-mentioned range, general anaerobic digestion method requires warming in the digester, while the medium- It becomes unnecessary. Therefore, it can be operated at the temperature within the above range without additional energy input, which is more economical.

The residence time in the medium-temperature single-phase digestion tank 600 may be 5 to 30 days, preferably 7 to 25 days, more preferably 10 to 20 days. The residence time of the organic waste in the medium temperature single stage digester 600 of the present invention is 20 days or more as compared with the case where the residence time of the organic waste in the digester is 30 days or more at a temperature of about 35 ° C in a general anaerobic digestion system, . This is because the treatment time is shortened due to the increase of the anaerobic digestion efficiency through the hydrolysis and solubilization, and the time for organic waste to stay in the medium-temperature single-phase digestion tank 600 is remarkably shortened. It is also effective in reducing the energy required for anaerobic digestion by increasing the efficiency of anaerobic digestion and shortening the residence time of the organic waste in the mid-temperature single-phase digestion tank (600).

Among the gaseous products produced through the anaerobic digestion, the biogas is introduced into the biogas purification facility 610 and purified. In addition to methane and carbon dioxide, impurities such as moisture, hydrogen sulfide, and siloxane are present in the gaseous products generated through anaerobic digestion in the medium-temperature single-phase digestion tank 600, and impurities are removed through the biogas purification facility 610.

In addition, the biogas from which the impurities have been removed through the biogas refining facility 610 may be recycled into the energy recycling facility 620 and utilized as a power generation or LNG fuel substitute. In more detail, the biogas produced by the organic waste anaerobic digestion system of the present invention is supplied to a gas generator to produce electricity, and the waste heat generated in the process of power generation is supplied to a thermal hydrolysis and solubilizing apparatus 500, a sludge drying apparatus 900, or the heat-hydrolysis-solubilizing apparatus 500 and the sludge drying apparatus 900, respectively. In addition, all of the electricity produced can be used in the organic waste anaerobic digestion system of the present invention or can be charged.

The biogas can be recycled as fuel for the thermohydrolysis and solubilization apparatus 500, the sludge drying apparatus 900, or the thermohydrolysis and solubilization apparatus 500 and the sludge drying apparatus 900. In addition, the biogas can be recycled as a boiler heat source. This can contribute to energy independence of the organic waste anaerobic digestion system of the present invention.

In addition, the energy independence rate is determined by the amount of biogas produced during anaerobic digestion, the amount of dry matter produced by drying the dehydrated sludge, or the amount of biogas generated and the amount of dried material dried by drying the dehydrated sludge. Accordingly, in the organic waste anaerobic digestion system of the present invention, the efficiency of anaerobic digestion and biogas generation can be improved through thermal hydrolysis and solubilization, and energy self-sufficiency rate of 50% or more can be achieved by using the above-described energy recycling system.

Meanwhile, FIG. 2 is a flowchart showing an embodiment of the organic waste anaerobic digestion method of the present invention.

As shown in FIG. 2, the present invention provides a method for producing organic wastes, comprising (A) a storage step (S4) for storing organic wastes; (B) the organic waste is heated at a temperature of 160 to 200 DEG C, preferably 180 to 200 DEG C, more preferably 190 to 200 DEG C and 5 to 10 bar, preferably 6 to 10 bar, more preferably 7 to 10 bar (S5) of thermally hydrolyzing the biopolymer to destroy the cell wall of the organic material and decomposing the biopolymer; (C) an anaerobic digestion step (S6) of anaerobically digesting the organic waste having undergone the hydrolysis and solubilization step to produce a gaseous product containing biogas and digested sludge; (D) a dehydrating step (S8) of dehydrating the digested sludge produced through the anaerobic digestion to produce dehydrated sludge; (E) drying (S9) drying the dehydrated sludge to produce a dried material; (F) a biogas purification step (S61) for separating the biogas out of the gaseous products produced through the anaerobic digestion; And (G) an energy recycling step (S62) using the dried material, the biogas, or the dried material and the biogas as fuel. The present invention also provides a method for anaerobic digestion of organic waste including thermal hydrolysis.

In the organic waste anaerobic digestion method of the present invention, the organic waste is subjected to the hydrolysis and solubilization step (S5) through the storage step (S4) prior to the anaerobic digestion step (S6) in earnest. The organic waste having undergone the thermal hydrolysis and solubilization step (S5) is heated at a temperature of 160 to 200 DEG C, preferably 180 to 200 DEG C, more preferably 190 to 200 DEG C and 5 to 10 bar, preferably 6 to 10 bar, Preferably 7 to 10 bar. This is an effective range in which the cell wall of the organic material in the organic waste is destroyed and the biopolymer is decomposed, and the biodegradable materials other than the cell wall may be destroyed. In addition, hydrolysis efficiency is increased because heat and pressure treatment are performed at the same time. Also, in this process, organic substances having a complicated structure are effectively solubilized by solubilizing materials such as monomers and oligomers, which enables faster and more efficient anaerobic digestion. Particularly, in the case of solid wastes such as organic wastes, this hydrolysis step is a very important process for the process efficiency and treatment time of the total anaerobic digestion method.

The organic waste having undergone the hydrolysis and solubilization step (S5) is subjected to an anaerobic digestion step (S6), whereby a gaseous product containing biogas is produced. At this time, since the organic waste in the anaerobic digestion step (S6) is thermally hydrolyzed and solubilized, the efficiency of the anaerobic digestion to react with the substrate is increased, and the production efficiency of the biogas that can be generated in the process is also increased. Compared with the general anaerobic digestion method, the anaerobic digestion in the organic waste anaerobic digestion method of the present invention enables the biogas generation to be increased by 40% or more, thereby increasing the recyclable energy and thus being economical in terms of energy recycling. In addition, since the treatment time is shortened due to the increase in the anaerobic digestion efficiency, the time required for the organic waste to stay in the anaerobic digestion step (S6) can be shortened. In addition, the energy required for anaerobic digestion is also reduced by increasing the anaerobic digestion efficiency and shortening the residence time.

In addition, the volume of the digester in the anaerobic digestion step (S6) of the organic waste anaerobic digestion method of the present invention can be reduced to about half of the volume of the anaerobic digestion tank used in the general anaerobic digestion method. This makes it easier to install and manage the facility, which makes it possible to operate a more stable digester and reduce operating energy. In addition, in the general anaerobic digestion method, the VS reduction rate is about 40%, whereas in the organic waste anaerobic digestion method including the thermal hydrolysis of the present invention, the digestion tank can be operated at a stable rate of 55% or more and the operation energy can be saved. In addition, the reduction of the digestion tank volume and the VS reduction rate as described above leads to the increase of the anaerobic digestion efficiency and the biogas generation amount. In particular, the biogas generation amount can be increased by 40% or more as compared with the general anaerobic digestion method.

In addition, the organic waste anaerobic digestion method of the present invention may further include a cooling step (S51) for lowering the temperature of the organic waste after the hydrolysis and solubilization step (S5) before the anaerobic digestion step (S6) . The thermally hydrolyzed organic waste that has undergone the cooling step (S51) is cooled to a temperature such as 38 to 39 DEG C at which the microbial growth can be optimally performed in the next anaerobic digestion step (S6). Since the cooled organic waste undergoes the anaerobic digestion step (S6), this may lead to an increase in the anaerobic digestion efficiency and a maximization of the biogas production. In the general anaerobic digestion method, warming and warming energy are required to maintain the digester at a temperature of about 35 ° C in case of mid-temperature digestion. Therefore, compared with the general anaerobic digestion method, the organic waste anaerobic digestion method of the present invention does not require the separate digestion tank warming, so that it is possible to save the energy required for heating and warming the digestion tank.

Further, the organic waste anaerobic digestion method of the present invention may further include a digestion sludge storage step (S7) for storing the digested sludge generated through the anaerobic digestion prior to the dehydration step (S8). In the digestion sludge storage step S7, the digested sludge discharged in the anaerobic digestion step S6 is temporarily stored, and the organic waste having been digested in the digestion sludge storage step S7 is dehydrated in the dehydration step S8, do. In the general anaerobic digestion method, the water content of the dehydrated sludge is around 80%, whereas in the organic waste anaerobic digestion method of the present invention, the dehydration due to thermal hydrolysis is very high, and the water dehydration sludge water content can be maintained at 70% or less. Therefore, it is possible to reduce the amount of dehydrated sludge generated and reduce the energy consumption required for treating the dehydrated sludge having a low water content even in the subsequent drying step, which is economical.

Further, the organic waste anaerobic digestion method of the present invention further includes a step S81 of treating the organic matter and phosphorus in the desorption filtrate, which occurs upon dehydration of the digested sludge produced through the anaerobic digestion step (S6) can do. The reduction and stabilization of digested sludge which is generated by anaerobic digestion in anaerobic digestion method is one of the important purposes of anaerobic digestion. Therefore, it is necessary to separate and reduce the amount of the desorption filtrate, which is the moisture of the digested sludge, through the dehydration step (S8), and to remove the organic substances and phosphorus in the desorption filtrate through the reflux water treatment step (S81).

In addition, the digested sludge produced through the anaerobic digestion is dehydrated in the dehydration step (S8), and the generated dehydrated sludge is dried in the drying step (S9) to produce a dried product.

In addition, the moisture content of the dried material after the drying step (S9) may be 1 to 10%, preferably 4 to 9%, more preferably 6 to 8%. This is a range in which the generation of odor is effectively prevented due to sufficient dehydration and drying of the digested sludge, and the volume is reduced to facilitate handling. In addition, since the water content is low, it is difficult to decay when discharged, and environmental pollution can be prevented. Further, since the dried material can be used as an auxiliary fuel for a thermal power plant or a cement kiln during the treatment, the entire system can be made more economical. In addition, in the organic waste anaerobic digestion method of the present invention, the cell wall of the organic material is destroyed and the biopolymer is decomposed in the step of hydrolysis and hydrolysis (S5), so that the dried material having a lower water content can be obtained. In other words, since hydrolysis and solubilization of substances including binding water such as cells and polymers in organic waste are reduced to decrease the number of binding, the water removal efficiency can be further increased.

In addition, the dried material can be recycled as an auxiliary fuel for a thermal power plant, a cement kiln, or a thermal power plant and a cement kiln. Further, the energy independence rate of the organic waste anaerobic digestion method of the present invention can be further increased and the fossil energy consumption can be reduced.

Meanwhile, the organic waste may be selected from the group consisting of sewage sludge, food waste, manure sludge, and mixtures thereof.

The manure sludge may also be manure sludge, livestock manure sludge or human manure sludge and livestock manure sludge.

Referring to FIG. 2, the organic waste anaerobic digestion method of the present invention may include a step of pre-treating organic wastes such as sewage sludge, food waste, and manure sludge before entering the storage step S4 have.

First, before the storage step S4, the step S11 of dewatering the sewage sludge may be further included. Generally, the sewage sludge is concentrated in the concentration tank of the sewage treatment plant and is treated by the anaerobic digestion method of the present invention. It is preferable that the water is firstly dewatered before entering the storage step S4 and thereafter enters the storage step S4 constituting the present invention desirable.

Also, prior to said retention step (S4), said food waste may further comprise a step of breaking and sorting (S21).

Further, before the storage step S4, the manure sludge may further include a step of removing and dewatering the contaminant (S31). As each organic waste is subjected to a pre-treatment step suited to the characteristics of each substrate as described above, it becomes easier to enter the mixing and storage step S4 of the organic waste. Further, it can be further stabilized as a substrate to be introduced into the thermodecomposing solubilization step (S5) via the storage step (S4), leading to a higher efficiency of thermo-hydrolysis solubilization.

The water content after dehydration may be 75 to 90%, preferably 80 to 85%, more preferably 82 to 84%. By dehydrating to the above-mentioned range, the volume of the total organic waste to be treated is remarkably reduced, so that the volume of the storage tank 400 to be subjected to the storage step S4 can be reduced and the handling is facilitated. In addition, since the water content of the organic wastes is also reduced, the sludge generated after the anaerobic digestion of the organic wastes can be reduced and the energy required for drying the wastes is also reduced.

The food wastes are selected so as to pass only particles having a particle diameter of 10 mm, preferably 7 mm, and more preferably 5 mm or less after the crushing process generally performed in the technical field of the present invention, (95% or more, preferably 97% or more) of various foreign substances such as vinyl, iron, plastics and bone can be entered into the storage step (S4). In addition, since the particle size is small, the volume of total organic waste is significantly reduced and handling is facilitated.

Further, in the case of the manure sludge, it is subjected to the step of removing and dehydrating the impurities (S31) in order to select foreign matters. By removing the contaminants through the contaminant removal and dehydration step (S31), the dehydration process after removing the contaminants can be made easier and the dehydration efficiency can be further improved.

In the organic waste anaerobic digestion method of the present invention, the anaerobic digestion step (S6) may be performed at 35 to 40 DEG C, preferably 37 to 40 DEG C, more preferably 38 to 39 DEG C. Since the temperature of the organic waste passing through the anaerobic digestion step (S6) is maintained at the temperature within the above-mentioned range, general anaerobic digestion method requires warming of the digestion tank, while in the anaerobic digestion step (S6) of the present invention, do. Therefore, it can be operated at the temperature within the above range without additional energy input, which is more economical.

In addition, the anaerobic digestion step (S6) may be performed for 5 to 30 days, preferably 7 to 25 days, more preferably 10 to 20 days. In the general anaerobic digestion method, the anaerobic digestion step (S6) of the present invention can be performed within 20 days, compared with the case where the mesophilic anaerobic digestion step at a temperature of about 35 DEG C takes about 30 days. This is because the treatment time is shortened due to the increase of the anaerobic digestion efficiency through the hydrolysis and solubilization, and the organic degradation time in the anaerobic digestion step (S6) is remarkably shortened. It is also effective in reducing the energy required for anaerobic digestion by increasing the efficiency of anaerobic digestion and shortening the time of anaerobic digestion (S6).

Among the gaseous products produced through the anaerobic digestion, the biogas is purified in the biogas purification step (S61). In addition to methane and carbon dioxide, impurities such as moisture, hydrogen sulfide, and siloxane are present in the gaseous products generated through the anaerobic digestion step (S6), and the impurities are removed through the biogas purification step (S61).

In addition, the biogas from which the impurities have been removed through the biogas purification step (S61) may be recycled in the energy recycling step (S62), such as being used as power generation or as an alternative to the LNG fuel. More specifically, the biogas produced by the organic waste anaerobic digestion method of the present invention is supplied to the gas generator through the energy recycling step (S62) to produce electricity, and the waste heat generated in the power generation step is subjected to heat hydrolysis and solubilization (S5), the sludge drying step (S9), or the hydrolysis and solubilization step (S5) and the sludge drying step (S9). In addition, the produced electricity can be used or consumed as the energy required for the organic waste anaerobic digestion method of the present invention.

In the energy recycling step S62, the biogas is recycled as fuel for the hydrolysis and solubilization step (S5), the sludge drying step (S9), or the hydrolysis and hydrolysis step (S5) and the sludge drying step (S9) can do. In addition, the biogas can be recycled as a boiler heat source. This can contribute to the energy independence necessary for the anaerobic digestion method of the organic waste of the present invention.

In addition, the energy independence rate is determined by the amount of biogas produced during anaerobic digestion, the amount of dry matter produced by drying the dehydrated sludge, or the amount of biogas generated and the amount of dried material dried by drying the dehydrated sludge. Accordingly, in the organic waste anaerobic digestion method of the present invention, the efficiency of anaerobic digestion and biogas generation can be improved through the thermodynamic hydrolysis and solubilization, and energy self-sufficiency rate of 50% or more can be achieved by using the above-mentioned energy recycling method.

Hereinafter, embodiments of the present invention will be described.

Example

Example  One : Thermal hydrolysis  + Anaerobic digestion

Organic wastes were anaerobically digested using an organic waste anaerobic digestion method and system comprising thermal hydrolysis of the present invention. COD and VS were used as indicators for the removal of organic substances in organic wastes according to the experimental results. Table 1 shows the influent substrate and removal characteristics of COD and VS according to anaerobic digestion days.

In order to measure the efficiency of gas production by anaerobic digestion, gas generation amount and methane content were measured according to anaerobic digestion days. The results are shown in Table 2.

In order to evaluate the digestion efficiency and gas production according to the measurement results, FIGS. 3 and 4 show experimental results on the gas generation rate according to the VS concentration and the anaerobic digestion days according to the anaerobic digestion days, respectively.

1. Inflow substrate and removal characteristics

division Influent substrate Removal Characteristics inflow
COD
(g / day) inflow
VS
(g / day) inflow
COD
(g / L) inflow
VS
(g / L) outflow
COD
(g / L) outflow
SCOD
(g / L) COD
Removal rate
(%) outflow
VS
(g / L) VS
Removal rate
(%) COD
Removal amount
(g) VS
Removal amount
(g) 1 day 15.3 5.7 59.3 36.1 23.0 1.7 61.3 21.7 39.8 181.9 71.8 2 days 18.3 6.8 - - - - - - - - - 3 days 18.7 6.9 - - - - - - - - - 4 days 17.7 6.5 - - 18.8 2.0 68.3 17.1 52.7 202.7 95.2 5 days 17.2 6.4 - - 24.9 1.5 58.0 15.8 56.3 172.0 101.7 6 days 19.0 7.0 - - 26.7 1.6 55.0 15.5 57.1 163.1 103.0 7 days 19.6 7.3 - - 29.6 1.4 50.2 16.8 53.6 148.9 96.7 8 days 15.1 5.6 - - 23.1 1.7 61.1 15.9 56.0 181.3 101.0 9th 15.7 5.8 - - 22.4 1.4 62.2 15.0 58.3 184.6 105.3 10 days 21.7 8.0 - - 24.9 1.5 58.0 14.8 58.9 172.1 106.4 11th 15.1 5.6 - - 25.0 1.6 57.8 15.0 58.4 171.5 105.4 12th 19.0 7.0 - - 23.6 1.8 60.3 14.9 58.6 178.8 105.8 13th 22.8 8.5 - - 24.1 1.6 59.4 14.8 58.9 176.3 106.3 14 days 17.5 6.5 - - 19.6 1.5 67.0 14.3 60.5 198.8 109.2 15th 15.7 5.8 - - 19.3 1.4 67.5 14.7 59.2 200.3 106.8 16th 17.8 6.6 - - 23.3 1.6 60.8 14.5 59.9 180.3 108.2 17th 20.2 7.5 - - 20.9 1.6 64.7 12.9 64.2 192.0 115.9 18th 23.4 8.7 - - 24.8 1.6 58.1 13.1 63.7 172.5 114.9 19th 25.1 9.3 - - 24.0 1.3 59.5 14.2 60.7 176.5 109.5 20 days 18.7 6.9 - - 23.9 1.3 59.8 14.9 58.6 177.3 105.9 21st 23.4 8.7 - - 23.7 1.3 60.1 14.8 59.0 178.3 106.6 22nd 24.0 8.9 - - 22.9 1.4 61.3 13.9 61.4 181.9 110.9

2. Gas production and methane content

division Gas generation amount Methane content
(%) Gas generation amount
(L) Cumulative gas generation
(L) Gas generation rate
(L / g COD) Gas generation rate
(L / gVS) 1 day 8.5 8.5 0.05 0.12 68.57 2 days 8.0 16.5 - - - 3 days 7.9 24.4 - - - 4 days 8.7 33.0 0.16 0.35 68.69 5 days 7.2 40.2 0.23 0.40 66.18 6 days 7.9 48.2 0.30 0.47 65.78 7 days 8.6 56.8 0.38 0.59 - 8 days 8.3 65.1 0.36 0.64 66.65 9th 8.5 73.6 0.40 0.70 - 10 days 8.4 82.0 0.48 0.77 69.61 11th 8.5 90.6 0.53 0.86 - 12th 5.7 96.3 0.54 0.91 69.69 13th 6.1 102.4 0.58 0.96 - 14 days 5.8 108.2 0.54 0.99 69.7 15th 5.1 113.3 0.57 1.06 - 16th 5.4 118.7 0.66 1.10 69.61 17th 5.6 124.3 0.65 1.07 - 18th 3.0 127.3 0.74 1.11 69.62 19th 2.5 129.8 0.74 1.19 - 20 days 2.4 132.2 0.75 1.25 69.55 21st 2.3 134.5 0.75 1.26 - 22nd 2.5 137.0 0.75 1.24 69.57

3. Evaluation of digestion efficiency and gas production

The VS concentration and digestion efficiency according to anaerobic digestion days are shown in FIG. 3 in order to examine the digestion efficiency characteristics based on the experimental results measured in the above Table 1.

The gas generation rate according to the number of days of anaerobic digestion is shown in FIG. 4 in order to examine the gas generation rate characteristics based on the experimental results measured in the above Table 2.

Comparative Example  1: General Solubilization  + Anaerobic digestion

Organic wastes were anaerobically digested using an anaerobic digestion method involving general physical solubilization. As in Example 1, COD and VS were used as indicators for the removal of organic substances in organic wastes according to the experimental results. Table 3 shows the influent substrate and removal characteristics of COD and VS according to anaerobic digestion days Respectively.

In order to measure the efficiency of gas production by anaerobic digestion, gas generation amount and methane content were measured according to anaerobic digestion days. The results are shown in Table 4.

In order to evaluate the digestion efficiency and the gas generation amount according to the measurement results, FIGS. 5 and 6 show experimental results of the gas generation rate according to the VS concentration and the anaerobic digestion days according to the anaerobic digestion days, respectively.

1. Inflow substrate and removal characteristics

division Influent substrate Removal Characteristics inflow
COD
(g / day) inflow
VS
(g / day) inflow
COD
(g / L) inflow
VS
(g / L) outflow
COD
(g / L) outflow
SCOD
(g / L) COD
Removal rate
(%) outflow
VS
(g / L) VS
Removal rate
(%) COD
Removal amount
(g) VS
Removal amount
(g) 1 day 13.2 5.8 52.6 35.0 36.5 2.5 30.7 27.1 - 80.7 39.3 2 days 11.6 5.1 - - - - - - - - - 3 days 10.8 4.8 - - 37.5 3.0 28.8 24.9 28.8 75.6 50.3 4 days 13.2 5.8 - - - - - - - - - 5 days 12.0 5.3 - - 30.8 3.1 41.4 25.8 26.3 109.0 46.0 6 days 14.0 5.5 56.0 32.0 - - - - - - - 7 days 13.2 5.2 - - 33.8 2.6 39.6 22.0 31.3 110.8 50.0 8 days 11.3 4.5 - - - - - - - - - 9th 12.2 4.8 - - 32.0 2.5 42.8 21.8 31.9 119.8 51.1 10 days 10.2 4.0 - - - - - - - - - 11th 17.6 6.9 - - 31.6 2.3 43.5 22.1 30.8 121.6 49.3 12th 12.0 4.7 - - - - - - - - - 13th 13.1 5.1 - - - - - - - - - 14 days 13.2 5.2 - - 34.0 2.5 39.2 21.7 32.3 109.8 51.7 15th 13.8 5.4 - - - - - - - - - 16th 19.5 5.5 78.2 30.0 - - - - - - - 17th 19.5 5.5 - - 28.0 2.1 64.2 20.2 32.6 250.8 48.9 18th 17.8 5.0 - - - - - - - - - 19th 19.5 5.5 - - - - - - - - - 20 days 22.3 6.3 - - - - - - - - - 21st 17.2 4.8 - - 24.9 2.2 68.1 18.9 36.9 266.3 55.4 22nd 15.2 4.3 - - - - - - - - - 23rd 21.1 5.9 - - - - - - - - - 24th 22.5 5.4 91.8 35.0 25.7 2.2 72.0 20.0 42.8 330.4 74.9 25th 23.4 5.6 - - - - - - - - - 26th 25.3 6.0 - - - - - - - - - 27th 24.6 5.9 - - - - - - - - - 28th 20.0 4.8 - - 24.0 1.9 73.9 18.1 48.2 339.2 84.3

2. Gas production and methane content

division Gas generation amount methane
content
(%) Gas generation amount
(L) Cumulative gas generation
(L) Gas generation rate
(L / g COD) Gas generation rate
(L / gVS) 1 day 2.2 2.2 0.03 0.06 - 2 days 2.6 4.9 - - - 3 days 2.2 7.1 0.09 0.14 - 4 days 2.6 9.7 - - 72.46 5 days 2.4 12.1 0.11 0.26 - 6 days 2.0 14.1 - - - 7 days 1.4 15.5 0.14 - - 8 days 1.4 16.9 - - - 9th 1.5 18.3 0.15 0.36 64.88 10 days 1.4 19.8 - - - 11th 2.0 21.8 0.18 0.44 - 12th 1.8 23.6 - - - 13th 1.1 24.7 - - - 14 days 1.6 26.3 0.24 0.51 72.1 15th 1.6 27.9 - - - 16th 1.7 29.6 - - - 17th 1.5 31.0 0.12 0.64 68.59 18th 1.3 32.3 - - - 19th 1.4 33.7 - - - 20 days 1.3 35.0 - - - 21st 1.3 36.3 0.14 0.66 73.3 22nd 1.0 37.4 - - - 23rd 1.0 38.3 - - - 24th 0.8 39.2 0.12 0.52 74.16 25th 1.1 40.2 - - - 26th 0.9 41.2 - - 73.77 27th 1.1 42.3 - - - 28th 1.1 43.4 0.13 0.51 73.5

3. Evaluation of digestion efficiency and gas production

The VS concentration and digestion efficiency according to anaerobic digestion days are shown in FIG. 5 to examine the digestion efficiency characteristics based on the experimental results measured in the above Table 3.

The gas generation rate according to the number of days of anaerobic digestion is shown in FIG. 6 in order to examine the gas generation rate characteristics based on the experimental results measured in Table 4 above.

As a result of the digestion efficiency analysis according to Example 1 and Comparative Example 1,

As shown in FIG. 3, in the case of the digestion efficiency according to Example 1, digestion efficiency was analyzed to be more than 59% based on the 15-day anaerobic digestion period.

In comparison, as shown in FIG. 5, the digestion efficiency according to Comparative Example 1 was analyzed to be 37% or less when the anaerobic digestion days were 20 days. Also, the digestion efficiency was 48.2% at the final digestion days of 28 days, and it was analyzed that it was difficult to satisfy the digestion efficiency of 55% even when the digestion days of about 30 days or more were secured.

On the other hand, as a result of analyzing the gas generation amount according to Example 1 and Comparative Example 1,

As shown in FIG. 4, in the case of the gas generation amount according to Example 1, the digestion gas generation amount was 1.0 L / gVS or more based on the anaerobic digestion days of 15 days.

As shown in FIG. 6, the gas generation amount according to Comparative Example 1 was 0.6 L / gVS when the anaerobic digestion days were 20 days, and the gas generation amount at the final digestion days 28 days was 0.51 L / gVS, it was confirmed that it is difficult to secure a sufficient amount of extinguishing gas.

Therefore, it was confirmed that the retention time of the organic waste in the anaerobic digestion tank and the amount of the extinguishing gas generated were increased by 170% in Example 1 as compared with the anaerobic digestion days of 15 days.

Table 5 summarizes the results of the above experiment and Table 5 shows the VS removal rate and the digestion gas generation amount according to Example 1 and Comparative Example 1 in terms of VS removal rate and digestion rate under the same HRT conditions according to Example 1 and Comparative Example 1, And the amount of gas generated.

division Comparative Example  One
(Normally Solubilization  + Anaerobic digestion ) Example  One
( Thermal hydrolysis  + Anaerobic digestion ) VS Removal Rate ( % ) 36.9 (HRT 21day condition)
48.2 (HRT 28day condition) 59.2 (HRT 15day condition)
59.0 (HRT 21day condition) The amount of extinguishing gas generated (L / gVS ) 0.66 (HRT 21day condition)
0.51 (HRT 28day condition) 1.06 (HRT 15day condition)
1.26 (HRT 21day condition)

division Comparative Example  One
(General solubilization + anaerobic digestion) Example 1
(Thermal hydrolysis + anaerobic digestion) HRT 21day
Condition VS Removal Rate (%) 36.9 59.0 Extinguishing gas generation amount (L / gVS) 0.66 1.26

As shown in the above results, the VS removal ratio according to Example 1 was 59% at the same HRT (21day) condition, which was 1.6 times higher than the VS removal rate according to Comparative Example 1 at 36.9%.

Based on this result, the inverse calculation based on the same VS removal rate means that HRT can be reduced 1.6 times in Example 1, which means that the digestion tank volume can be reduced 1.6 times. In addition, the amount of extinguishing gas generated in the same HRT (21day) condition was 1.9 times higher than that in Comparative Example 1, and the amount of extinguishing gas generated in Example 1 was 1.9 times higher than that in Comparative Example 1.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course it is possible. Accordingly, the scope of the present invention should not be construed as being limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the following claims.

100: Sewage sludge storage tank 110: Sewage sludge dehydrator
200: Food waste storage tank 210: Pretreatment device
300: Poultry sludge storage tank 310: Contamination processor
320: Poultry sludge dehydrator 400: Storage tank
500: thermal hydrolysis solubilizer 510: cooler
600: Medium temperature single phase digester 610: Biogas refinery
620: Energy recycling facility 700: Digestion sludge reservoir
800: dehydrator 810: reflux water treatment device
900: Sludge drying device

Claims (22)

A reservoir for storing organic waste;
A thermohydrolysis solubilizer for thermally hydrolyzing the organic waste supplied from the storage tank at 160 to 200 ° C and 5 to 10 bar to break the cell walls of the organic material and decompose the biopolymer;
A medium-temperature single-phase digestion tank for anaerobically digesting the organic waste having undergone the thermal hydrolysis and solubilization to produce a gaseous product containing biogas and digested sludge;
A dehydrator for dehydrating the digested sludge produced through the anaerobic digestion to produce dehydrated sludge;
A sludge drying device for drying the dehydrated sludge dewatered by the dehydrator to produce a dried material;
A biogas refining facility for separating the biogas from the gaseous products produced through the anaerobic digestion; And
An organic waste anaerobic digestion system comprising an energy recycling facility using the dry matter, biogas, or dried matter and biogas as fuel.
The method according to claim 1,
Further comprising a cooler for lowering the temperature of the organic waste prior to the addition to the medium-temperature single-phase digestion tank.
The method according to claim 1,
Further comprising a reflux water treatment device for removing organic substances and phosphorus in the desorption filtrate generated in the dehydrator.
The method according to claim 1,
Wherein the organic waste is selected from the group consisting of sewage sludge, food waste, manure sludge, and mixtures thereof.
The method of claim 4,
Wherein the sewage sludge is transferred to the storage tank after dewatering.
The method of claim 4,
Wherein the food waste is transported to the storage tank after crushing and sorting.
The method of claim 4,
Wherein the manure sludge is conveyed to the storage tank after removal of dirt and dehydration.
The method according to claim 5 or 7,
Wherein the water content after dehydration is 75 to 90%.
The method according to claim 1,
Wherein the moisture content of the dried product after drying is 1 to 10%.
The method according to claim 1,
Wherein the medium-temperature single-phase digestion tank is provided with a scum removing device for removing scum.
The method according to claim 1,
Wherein the medium-temperature single-phase digestion tank has a cyclone below the organic waste anaerobic digestion system for removing sediments and returning the microorganisms to the digester.
The method according to claim 1,
Wherein the biogas is supplied to a gas generator to produce electricity, and the waste heat generated in the power generation process is recycled as a heat source for a thermal hydrolysis and solubilization device, a sludge drying device, a thermal hydrolysis solubilizing device and a sludge drying device , Organic waste anaerobic digestion system.
The method according to claim 1,
Wherein the biogas is recycled as a fuel for a thermal hydrolysis solubilization device, a sludge drying device, or a thermal hydrolysis solubilizing device and a sludge drying device.
(A) a storage step for storing the organic waste;
(B) thermally hydrolyzing the organic waste at 160 to 200 ° C and 5 to 10 bar to decompose the cell wall of the organic material and decompose the biopolymer;
(C) an anaerobic digestion step of anaerobically digesting the organic waste after the hydrolysis and solubilization step to produce a gas product containing biogas and digested sludge;
(D) a dehydrating step of dehydrating the digested sludge produced through the anaerobic digestion to produce dehydrated sludge;
(E) drying the dehydrated sludge to produce a dried product;
(F) a biogas purification step of separating the biogas from the gaseous products produced through the anaerobic digestion; And
(G) An organic waste anaerobic digestion method comprising the step of recycling the dried material, the biogas, or the dried material and the biogas as fuel.
15. The method of claim 14,
Further comprising a cooling step prior to the anaerobic digestion step to lower the temperature of the organic waste having undergone the hydrolysis and solubilization step.
15. The method of claim 14,
Further comprising a reflux water treatment step of removing organic substances and phosphorus in the desorption filtrate which occurs upon dehydration of the digested sludge produced through the anaerobic digestion.
15. The method of claim 14,
Wherein the organic waste is selected from the group consisting of sewage sludge, food waste, manure sludge, and mixtures thereof.
18. The method of claim 17,
Further comprising dewatering the sewage sludge prior to the storage step. ≪ RTI ID = 0.0 > 11. < / RTI >
18. The method of claim 17,
Characterized in that prior to the storage step, the food waste further comprises a step of crushing and sorting.
18. The method of claim 17,
Characterized in that prior to the storage step, the manure sludge further comprises a step of removing contaminants and dewatering.
15. The method of claim 14,
In the energy recycling step, the biogas is supplied to a gas generator to produce electricity, and the waste heat generated in the power generation is recycled as a heat source for the hydrolysis and solubilization step, the sludge drying step, or the hydrolysis and solubilization step, Wherein the anaerobic digestion of organic wastes is carried out at a temperature of about < RTI ID = 0.0 >
15. The method of claim 14,
Wherein the biogas is recycled as fuel for the hydrolysis and solubilization step, the sludge drying step, or the hydrolysis and solubilization step and the sludge drying step in the energy recycling step.

Images