JP2011045882A - Method for producing adsorbent and method for producing alcohol or organic acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorbent produced using a biomass residue, a method for producing the adsorbent, and a method for producing an alcohol or organic acid using the adsorbent. <P>SOLUTION: The method for producing an adsorbent comprises drying or carbonizing a biomass residue generated in a process for producing the alcohol or organic acid from a raw-material biomass. The adsorbent provided herein is obtained by the production method. The method for producing the alcohol or organic acid comprises using the adsorbent in the method for producing the alcohol or organic acid from the raw-material biomass. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an adsorbent that effectively uses biomass residues generated when alcohol or organic acid is produced from raw biomass, a method for producing the adsorbent, and a method for producing alcohol or organic acid using the adsorbent.

  In recent years, from the viewpoint of global warming countermeasures and the effective use of waste, the use of biomass from plant resources has attracted attention. By converting biomass into alcohol such as ethanol and organic acids, it can be used as energy and chemical raw materials. Research to use is underway. In particular, attention has been focused on technology for producing ethanol, which is attracting attention as a next-generation automobile fuel, from biomass.

  Generally, sugars such as sugar cane and starches such as corn are often used as raw material biomass for producing ethanol and the like. Other examples include cellulosic resources such as plant biomass such as bagasse and rice straw, and woody biomass such as wood chips.

  When ethanol is produced from the collected cellulose resources, first, saccharification pretreatment is performed by physical methods such as grinding, steaming, and explosion, or chemical methods using acids and alkalis, followed by acid hydrolysis and enzymatic decomposition. To decompose into saccharides such as hexose and pentose (saccharification process).

  Next, the saccharides obtained in the saccharification step are fermented by microorganisms and converted to ethanol (fermentation step). However, when acid or alkali is used in the saccharification pretreatment or saccharification step, they are added before It is preferable to neutralize (neutralization step). And the fermented material containing ethanol can be separated and purified by distillation to obtain ethanol (distillation step).

  At this time, biomass residue is generated from each step. That is, a saccharification residue is generated from the saccharification step, a neutralization residue and sludge from the neutralization step, a fermentation residue from the fermentation step, and a distillation residue from the distillation step. Since these biomass residues contain a large amount of unused organic matter, disposing of them will result in a loss of energy recovery, but currently they are treated as waste by methods such as landfill, incineration, and methane fermentation. Yes.

  On the other hand, it is known that a carbide obtained by heat-treating a wood material containing cellulose under a predetermined temperature condition and oxygen condition is used as an adsorbent, a catalyst, and an ion exchanger (for example, Patent Document 1). reference.). However, the above-mentioned carbides are not produced by using biomass residue effectively, using cellulose, starch, or unused plant resources such as woody waste and agricultural waste containing these as raw materials.

Japanese Patent No. 3138749

When landfilling biomass residue, a vast disposal site is required. Incineration and methane fermentation can reduce the volume of biomass residue and recover heat, but in this case, it is necessary to consider excessive facilities and handling of the resulting heat and biogas. However, it is not necessarily an effective means.
Therefore, the present invention provides an adsorbent using biomass residue generated in the process of producing alcohol or organic acid from raw biomass, a method for producing the adsorbent, and a method for producing alcohol or organic acid using the adsorbent. Objective.

  The present invention pays attention to a biomass residue that is disposed of as waste even though it contains a large amount of unused organic matter, and as a result of earnestly examining a method for effectively using this, the biomass residue is dried or carbonized. As a result, it was found that an excellent adsorbent was obtained, and the present invention was completed.

That is, in the method for producing an adsorbent of the present invention, a biomass residue generated in the process of producing an alcohol or an organic acid from raw material biomass is subjected to acid hydrolysis at 130 to 230 ° C. for 3 to 30 minutes, and the obtained saccharification residue is dried. Or, it is carbonized.
The method for producing alcohol or organic acid according to the present invention comprises subjecting biomass residue generated in the process of producing alcohol or organic acid from raw biomass to acid hydrolysis at 130 to 230 ° C. for 3 to 30 minutes, and drying the obtained saccharification residue Alternatively, an adsorbent obtained by carbonization is used.

  According to the present invention, the biomass residue that has been disposed of in the past can be effectively used despite the fact that it contains a large amount of unused organic matter. It can be said that it is useful.

  The adsorbent of the present invention is produced by drying a biomass residue generated in the process of producing an alcohol or an organic acid from raw material biomass. Here, raw material biomass means a plant that is the primary product of solar energy, sugar-based biomass such as sugar cane, starch-based biomass such as corn, plant-based biomass such as bagasse and rice straw, and wood chips. Although woody biomass and the like are included, carbohydrate biomass and starch biomass are inherently edible resources. Therefore, it is preferable to use raw material biomass containing cellulose, such as vegetation biomass and woody biomass. In particular, surplus agricultural products, agricultural waste, thinned wood, and wooden building materials are preferably used. Examples of agricultural waste include bagasse and rice straw. Examples of the woody building materials include lumber process residue, product production process residue, new construction, building waste generated from the demolition site, and general waste woody waste such as furniture.

The biomass residue used in the present invention includes at least one of saccharification residue, neutralization residue, fermentation residue, and distillation residue. Among these, saccharification residue is preferably used because cellulose and hemicellulose are removed from the saccharification residue and the portion easily forms a pore structure during carbonization.
Here, the biomass residue is generated in the process of producing alcohol or organic acid from raw material biomass, and mainly contains lignin.
The “saccharification residue” means a residue separated from a solution containing a saccharide obtained in a saccharification step described later.
The “neutralization residue” means a water-containing solid content generated by mixing an organic acid and the like when an alkali salt used for neutralization is precipitated, and including an inorganic substance and an organic substance.
“Fermentation residue” means a residue separated from an organic compound such as an alcohol or an organic acid obtained in a fermentation process described later.
The “distillation residue” means waste water after separation and purification of the target organic compound in the distillation step described later.

Hereinafter, a method for producing an organic compound such as alcohol or organic acid from raw material biomass will be described.
As a method for producing alcohol or organic acid from raw material biomass, any known method can be used, and examples thereof include a production method including a saccharification step, a neutralization step, a fermentation step, and a distillation step. Hereinafter, although each process is demonstrated one by one, it can change suitably according to the kind etc. of raw material biomass to be used.

A saccharification process says the process of hydrolyzing from polysaccharides, such as a cellulose and a hemicellulose, to the saccharide | sugar to monosaccharide-about 2 saccharides. As a hydrolysis method, a conventionally known method can be used, but an acid hydrolysis method is particularly preferably used. As the acid used in the acid hydrolysis method, sulfuric acid is preferable, and one having a sulfuric acid concentration of 0.5 to 5% by mass is particularly preferable. Moreover, as conditions of hydrolysis (saccharification), it is preferable to make it react for 3 to 30 minutes at 130-230 degreeC, More preferably, it is 3 to 10 minutes at 150-210 degreeC.
The hydrolysis reaction is stopped by extracting the reactants from the reactor and lowering the temperature. After the reaction is stopped, the solution containing saccharides from monosaccharide to about 2 saccharides is filtered and washed with a filter such as a horizontal belt filter or tray filter to separate the saccharide-containing solution from the saccharification residue.

  As pretreatment for the saccharification step, saccharification pretreatment is preferably performed. The saccharification pretreatment is performed in order to promote the hydrolysis reaction in the saccharification step, and is roughly divided into two methods, a physical method and a chemical method. Examples of the physical method include a method of pulverizing, steaming, and exploding the collected raw material biomass. Examples of the chemical method include a method of treating the collected raw material biomass with an acid and an alkali. By performing such saccharification pretreatment, the hydrolysis reaction in the saccharification step can be promoted, the hydrolysis rate with respect to the amount of the reagent used for hydrolysis is improved, and the yield of saccharides is increased. In addition, the amount of reagent used to obtain the same degree of hydrolysis can be reduced.

  When acid or alkali is used in the saccharification pretreatment or saccharification step, the pH of the solution containing the saccharide is adjusted (neutralization step). As pH after adjustment, pH 5-9 is preferable. The reagent used for adjusting the pH of the solution is appropriately selected according to the pH of the solution containing saccharides. For example, when the solution before neutralization is alkaline, hydrochloric acid or sulfuric acid may be used. When the solution is acidic, sodium hydroxide, calcium hydroxide, ammonia and the like can be mentioned. Among these, it is preferable to use a reagent containing calcium such as calcium hydroxide. When a reagent containing calcium is used, the calcium content in the neutralization residue generated in the neutralization process is increased, and by using such a calcium-containing neutralization residue as a biomass residue for the production of an adsorbent, for example, Compared with biomass residues not containing calcium, such as imparting phosphorus adsorption capacity in water treatment, an adsorbent exhibiting high functionality can be obtained. The neutralization residue generated in the neutralization step is separated by sedimentation separation or the like.

  The fermentation process refers to a process of converting monosaccharides to ethanol or organic acids by fermentation with microorganisms. Examples of microorganisms used for fermentation include yeast and bacteria, but genetically modified microorganisms are also preferably used. Genetically modified microorganisms are those in which these genes are introduced into a microorganism that does not have an enzyme gene necessary for conversion to ethanol or the like by genetic engineering technology, and fermentation to ethanol or the like is made possible. Examples of the genetically modified microorganism include genetically modified Escherichia coli having alcohol fermentability.

The conditions for fermentation in the fermentation process are appropriately determined according to the microorganism used.
Moreover, the fermentation residue generated in the fermentation process is separated by a centrifuge or the like.

  The organic compound obtained in the fermentation process is an alcohol or organic acid having 2 to 4 carbon atoms. Examples of the alcohol having 2 to 4 carbon atoms include ethanol, i-propanol, and n-butanol, and ethanol is most preferable. Examples of the organic acid include lactic acid, formic acid, acetic acid, propionic acid, butyric acid, citric acid, malic acid, fumaric acid, succinic acid and the like, and lactic acid is most preferable.

  A distillation process says the process of isolate | separating the target alcohol or organic acid by distillation from the solution containing the organic compound obtained by a fermentation process.

Of the raw material biomass, only the polymer sugar portion is used for conversion to alcohol or organic acid, and therefore the biomass residue has a void structure and a large surface area. Therefore, an excellent adsorbent can be produced by drying or carbonizing the biomass residue.
The method for drying the biomass residue is not particularly limited as long as the moisture content in the adsorbent is 10% by mass or less. For example, by drying with a kiln type dryer or a steam tube type dryer. Can be achieved quickly.

Moreover, as a method of carbonizing a biomass residue, the method of heating at 300-1000 degreeC on conditions under poor oxygen can be illustrated. Here, “under oxygen” means an oxygen concentration of 10% or less, preferably 5% or less, particularly preferably 3% or less. Moreover, it becomes possible to process a large amount of biomass residue at a time by using the rotary kiln used for cement manufacture etc. as a heating furnace.
Since the carbide thus obtained has a large number of pores, it functions sufficiently as an adsorbent.

  It is preferable to further activate the biomass residue after drying or carbonizing. By applying the activation treatment, it can be used as activated carbon.

  The adsorbent obtained in this way is used, for example, for removing persistent substances and colored substances from waste water.

Moreover, the adsorbent obtained by this invention is used suitably in the manufacturing method of organic compounds, such as alcohol or an organic acid, especially a neutralization process from the above-mentioned raw material biomass.
Hereinafter, the present invention will be described in more detail with reference to examples.

Production of adsorbent Cedar wood chips were hydrolyzed at 160 ° C. in 2% dilute sulfuric acid. Subsequently, the remaining solid content (70% by mass with respect to the cedar wood chip solid content) was taken out from the hydrolyzer, and washed with water until no sulfuric acid remained in the washing water. Furthermore, dehydration was performed while washing using a vacuum filter. The dehydrated residue was dried at 105 ° C. for a whole day and night using a thermostatic device (air bath). The moisture content of the residue after drying was 3.5%. Next, the dried product was heat-treated at 800 ° C. for 2 hours using an electric furnace (oxygen content 5.0%) purged with nitrogen to obtain a carbide (adsorbent: 40% by mass based on solid content of cedar wood chips). Got.

Decolorization treatment of biomass alcohol wastewater When wastewater generated when alcohol is produced from woody biomass is biologically treated (methane fermentation and activated sludge treatment), organic matter in the wastewater is removed, but coloring components remain. When this biological treatment liquid was passed through the adsorption tower filled with the adsorbent produced in Example 1, the colored components were adsorbed and the treatment liquid became colorless and transparent. The experimental conditions are as follows.
Column shape Diameter 30cm x Height 400cm (Adsorbent filling height 250cm)
Adsorbent packing density 200kg / m3
Flow rate 0.18m / h
Cylinder speed 0.72h-1
Fluid temperature 20 ℃
The results are shown in Table 1.

Examination of fermentation efficiency In the process of producing alcohol or organic acid from woody biomass, there is a neutralization step for adjusting the pH of the fermentation stock solution to an optimum pH. In this step, the fermentation inhibitor is precipitated and removed together with pH adjustment. By mixing the adsorbent prepared in Example 1 with the fermentation stock solution in the pre-fermentation adjustment step, the fermentation inhibitor dissolved in the solution was adsorbed, and the fermentation efficiency was improved. The experimental conditions are as follows.
Adsorption Adsorbent addition amount 1% by weight of fermentation broth
Adsorption time 10 minutes Fermentation Fermentation temperature 30 ℃
Fermentation time 48 hours Bacteria used Saccharomyces cerevisiae
Inoculum addition rate 5% by weight of culture broth based on fermentation stock solution
Nutrient salt and addition rate 0.5% by weight of corn steep liquor
The results are shown in Table 2.

  It is clear that ethanol can be produced with high efficiency by the method of the present invention.

  The present invention can be used in the field of producing alcohols and organic acids.

Claims (2)

  Production of adsorbent characterized by acid hydrolysis of biomass residue generated in the process of producing alcohol or organic acid from raw material biomass at 130-230 ° C. for 3-30 minutes, and drying or carbonizing the obtained saccharification residue Method. Utilize an adsorbent obtained by acid hydrolysis of biomass residue generated in the process of producing alcohol or organic acid from raw material biomass at 130-230 ° C. for 3-30 minutes, and drying or carbonizing the obtained saccharification residue A method for producing an alcohol or organic acid, characterized in that: