CN104880540A - Device and method of measuring biochemical methanogenesis potential of organic solid waste - Google Patents

Abstract

The invention discloses a device and a method of measuring biochemical methanogenesis potential of organic solid waste. The device comprises an electrothermostat cover, an electrothermostat base, an anaerobic fermentation device, a magnetic stirring disk, a temperature controller and a magnetic stirring disk controller; the measuring method comprises the following steps: the connection of the device and the detection of airtightness, the inoculums selection and preprocessing, the configuration of an anaerobic fermentation system, the building of an anaerobic environment system, the measuring of gas volume and the determination of gas components, and the calculation of biochemical methanogenesis potential. The device provided by the invention has the advantages of being simple in structure, easy to produce and install, long in service life, small in floor area and strong in adaptability; furthermore, the method is precise and reliable to measure, good in repeatability, and easy to operate the measuring process.

Description

A kind of apparatus and method measuring organic solid castoff biochemical methane potentiality

[technical field]

The present invention relates to organic solid castoff anaerobic digestion techniques field, particularly a kind of apparatus and method measuring organic solid castoff biochemical methane potentiality.

[background technology]

Along with the increase of regenerative resource demand, the technology utilizing the organic wastes such as anaerobic digestion techniques process organic waste, feces of livestock and poultry, stalk, energy crop to produce clean energy resource biogas is found broad application.During anaerobic ferment process design, biochemical methane potentiality weigh the important instrument of its feasibility, and biochemical methane potentiality also can provide the kinetic parameter of anaerobic fermentation simultaneously, is the important parameter evaluating anaerobic digestion process quality.

At present, the assay method of conventional biochemical methane potentiality, collects metering method difference according to installation for fermenting and gas volume and can be divided into drainage, syringe method and manometry.

1) drainage: the method generally flows in graduated cylinder with the water produced in installation for fermenting in gas extrusion recorder jar, carrys out the volume of meter gaseous.The method running program is simple and easy to implement, and apparatus structure is simple and easy to build, and maintenance cost is low.But there is following problem in the method in implementation process: (1), owing to considering the sealing of gas piping device, generally adopt static fermentation, this easily causes solid waste can not be uniformly distributed in anaerobic system at anaerobic fermentation process; (2) the easy syphonic effect of the liquid in drainage procedure in receiving flask, thus cause the method comparatively large to gas volume metering error, experimental precision is low; (3) the method needs, regularly to supplementing water in drain vessel, to add operator's work; (4) the method gathers gaseous sample difficulty, is difficult to carry out gas composition mensuration; (5) device is complicated, and volume is comparatively large, comprises fermentation flask, gas bottle and volume metering mechanism, is unfavorable for carrying out a large amount of sample determination.Above reason causes the method test error comparatively large, and precision is not high, and wastes time and energy.

2) syringe method: the method adopts large syringe as installation for fermenting and gas collector, whole device is positioned in fixing constant temperature rotating disk, carrys out meter gaseous volume by syringe piston displacement.As the method that German biomass energy research centre (DBFZ) is recommended.The advantage of the method is the simple saving of labor that operates, fermentation substrate mixing mixing.But in implementation process, there is following problem in the method: the sealing completely of (1) syringe is more difficult; (2) due to syringe finite volume, cylinder piston displacement can not be excessive, thus makes the addition of fermentation substrate limited, and the homogeneity of test and representativeness are not strong, and test accuracy is low; (3) the method gaseous sample gathers difficulty, and biogas component is difficult to measure.

3) manometry: anaerobic fermentation process and gas collection process are generally concentrated in one apparatus by the method, adopts handheld portable tensimeter metering gaseous tension gaseous tension, then calculates gas volume by the equation of gas state.The method test favorable reproducibility, precision is high, and gaseous sample collection is easy.But in reality is implemented, due to the hand-held gas gauge meter gaseous pressure of needs, and need the mixed gas of meter in Cycle-release installation for fermenting, waste time and energy concerning operator.Meanwhile, need repeatedly to penetrate with syringe needle the rubber plug sealing bottleneck at every turn in testing, make the method very high to the quality requirements of rubber plug, expensive.Above reason makes the popularization of the method limited.

Meanwhile, in test, be subject in organic solid castoff biochemical methane potentiality test process to be permitted multifactor impact.As the adding proportion of such as inoculum and substrate, substrate particle diameter, organic loading, the pre-incubation time of inoculum, environmental baseline, the buffer system etc. of anaerobic fermentation.

[summary of the invention]

The object of the invention is for above-mentioned existing problems, there is provided that a kind of structure is simple, fabrication and installation convenient, cheap, easy to implement with control, the apparatus and method of mensuration organic solid castoff biochemical methane potentiality that test accuracy is high, this device adopts the Key experiments program-control test condition and the reliable computing method of science that controllability is strong, realizes the biochemical methane potentiality Accurate Measurement to specific organic solid castoff.

Technical solution of the present invention:

A kind of device measuring organic solid castoff biochemical methane potentiality, comprise electrothermostat cover, electrothermostat base, anaerobic ferment devices, magnetic agitation dish, temperature controller and magnetic agitation disk controller, electrothermostat cover is the bottomless glass box cover of rectangle, and top cover is provided with two Waste gas outlets; Electrothermostat base is rectangular closed box body, magnetic agitation dish is positioned on electrothermostat base, anaerobic ferment devices is located on magnetic agitation dish, and the sealing of electrothermostat cover is buckled on electrothermostat base, and temperature controller and magnetic force stir disk controller and is located in electrothermostat base; Anaerobic ferment devices is made up of high-boron-silicon glass bottle, sealing bottle screw cap, accurate gas gauge, metal airway, unidirectional gas valve, high-boron-silicon glass fermentation flask is sealed by seal bottle cap, two metal airways are vertically fixed on blend rubber pad and gastight adhesive on seal bottle cap respectively and seal, wherein a metal airway upper end is connected with accurate gas gauge and is provided with unidirectional gas trap, an other metal airway upper end is exhausr port and is provided with unidirectional gas trap, and magnetic agitation rotor is arranged at bottom high-boron-silicon glass fermentation flask.

Described anaerobic ferment devices quantity is 12-36.

Utilize described device to measure a method for organic solid castoff biochemical methane potentiality, step is as follows:

1) complete the connection of said apparatus, and airtight test is carried out to this device, be close to lid place sheathed catheter O type rubber ring, and seal with gastight adhesive;

2) inoculum is selected and pre-service

Select and the anaerobic sludge of the methane-generating pit of operational excellence close with organic solid castoff character to be measured as inoculum, and with the screen cloth in 1-2mm aperture, inoculum is filtered, then be positioned over preculture 5-10 days in the identical incubator of test fermentation temperature, activated sludge also consumes the nutriment in inoculum further;

3) configuration of anaerobic fermentation system

With volatile solid content (VS) for benchmark, use preculture good seed sludge and organic solid castoff to be measured configure anaerobic fermentation system, for preventing organic solid castoff Middle nutrition material to be measured unbalanced and the anaerobic fermentation system wild effect caused, the adding proportion of inoculum and organic solid castoff to be measured is set to 2:1, whole anaerobic fermentation system occupies the 60-75% of anaerobic fermentation vial total measurement (volume), the biogas that all the other volumes produce for collecting anaerobic fermentation.In order to eliminate the biogas of inoculum generation to the impact of net result, test arranges the blank not adding fermentation substrate; Simultaneously in order to investigate the activity of inoculum, test arranges positive control, and positive control, according to fermentation substrate different in kind to be measured, arranges cellulose powder, fat or protein, and above all process all in triplicate;

4) foundation of anaerobic environment system

Before lid bottle cap, in high-boron-silicon glass bottle, pass into high pure nitrogen, continue 2-3 minute, to replace the air at head space place in bottle, form oxygen-free environment, then tighten bottle cap, carry out sealing, be placed into during electric heating is cultivated and start to carry out anaerobic fermentation;

5) metering of gas volume and the mensuration of gas composition

Reading in the accurate gas gauge of regular reading, (standard atmospheric pressure under institute's measuring pressure being scaled the status of criterion by the equation of gas state, 0 DEG C) volume of gas, and from anaerobism bottle, remove 2mL gas in headspace sampling bottle with injector for medical purpose, by gas chromatograph for determination biogas component.Until when aerogenesis slope of a curve goes to zero, stop test.

6) biochemical methane potentiality calculate

Biochemical methane potentiality (BMP) computing formula (Nml/gVS):

$\mathrm{BMP}(\mathrm{Nml}/\mathrm{gVS})=\frac{{\mathrm{\Σ}}_{i=1}^n[(\mathrm{Pi}\×V\×\mathrm{Ci}-\mathrm{Pj}\×V\×\mathrm{Cj})\÷101.325\×273\÷(273+T)]}{m}$

Pi: add gaseous tension in the anaerobism bottle of fermentation substrate, unit is kPa;

Ci: add methane concentration in the anaerobism bottle of fermentation substrate, unit is %;

Pj: do not add gaseous tension in the anaerobism bottle of fermentation substrate (blank), unit is kPa;

Cj: do not add methane concentration in the anaerobism bottle of fermentation substrate (blank), unit is %;

101.325: the air pressure number being 1 standard atmospheric pressure, unit is kPa.

T: anaerobic fermentation temperature, unit is DEG C;

M: be volatile solid (VS) quality of fermentation substrate, unit is g.

Advantage of the present invention is:

1) biochemical methane potentiality determinator proposed by the invention, anaerobic fermentation unit and gas collection unit, gas volume are measured unit concentrate be integrated, significantly reduce the volume of anaerobic reaction device, be convenient to the test carrying out a large amount of sample;

2) anaerobic fermentation Inoculant proposed by the invention adopts close with fermentation substrate character to be determined and in the methane-generating pit of operational excellence, ensure that the harmony of the nutriment of anaerobic fermentation system and the stability of anaerobic fermentation environment;

3) gas-metering device proposed by the invention and metering method, the accurate gas gauge original position be installed on anaerobic fermentation bottle cap is adopted to read in real time, time saving and energy saving compared with conventional method, gas volume under utilizing the equation of gas state gas volume to be scaled the status of criterion during gas volume metering simultaneously, ensures the comparability of acquired results;

4) biochemical methane potentiality method of testing proposed by the invention uses blank and positive control, ensure that the accuracy of data, repeatability and credibility.

[accompanying drawing explanation]

Fig. 1 is the apparatus structure schematic diagram measuring organic solid castoff biochemical methane potentiality.

Fig. 2 is anaerobic ferment devices structure enlarged diagram.

Fig. 3 is maize straw, wheat stalk methane phase curve.

In figure: 1. electrothermostat cover; 2. anaerobic ferment devices; 3. magnetic agitation dish; 4. temperature controller; 5. magnetic force stirs disk controller; 6. Waste gas outlet; 7. electrothermostat base; 8. high-boron-silicon glass fermentation flask; 9. seal bottle cap; 10. magnetic agitation rotor; 11. unidirectional gas traps; 12. accurate gas gauges; 13. metal catheters; 14. exhausr ports.

[embodiment]

Below with reference to accompanying drawing, technical scheme of the present invention is described further, fully to understand object of the present invention, characteristic sum effect.

Embodiment 1:

A kind of device measuring organic solid castoff biochemical methane potentiality, as shown in Figure 1-2, comprise electrothermostat cover 1, electrothermostat base 7, anaerobic ferment devices 2, magnetic agitation dish 3, temperature controller 4 and magnetic agitation disk controller 5, electrothermostat cover 1 is the bottomless glass box cover of rectangle, and top cover is provided with two Waste gas outlets 6, electrothermostat base 7 is rectangular closed box body, magnetic agitation dish 3 is positioned on electrothermostat base 7, anaerobic ferment devices is located on magnetic agitation dish 3, electrothermostat cover 1 sealing is buckled on electrothermostat base 7, and temperature controller 4 and magnetic force stir disk controller 5 and is located in electrothermostat base 7, anaerobic ferment devices 2 is by high-boron-silicon glass bottle 8, sealing bottle screw cap 9, accurate gas gauge 12, metal airway 13, unidirectional gas valve 11 forms, anaerobic ferment devices 2 has 12, high-boron-silicon glass fermentation flask 8 is sealed by seal bottle cap 8, two metal airways 13 are vertically fixed on blend rubber pad and gastight adhesive on seal bottle cap 9 respectively and seal, wherein a metal airway upper end is connected with accurate gas gauge 12 and is provided with unidirectional gas trap 11, an other metal airway upper end is exhausr port 14 and is provided with unidirectional gas trap 11, magnetic agitation rotor 10 is located at bottom high-boron-silicon glass fermentation flask 8.

Utilize the method for said determination organic solid castoff biochemical methane potentiality, comprise following steps:

1) complete the connection of said apparatus, and airtight test is carried out to this device, be close to lid place sheathed catheter O type rubber ring, and seal with gastight adhesive;

2) inoculum is selected and pre-service

Select and the anaerobic sludge of the methane-generating pit of operational excellence close with organic solid castoff character to be measured as inoculum, and with the screen cloth in 1mm aperture, inoculum is filtered, then preculture is positioned in the identical incubator of test fermentation temperature 7 days, activated sludge the nutriment consumed further in inoculum;

3) configuration of anaerobic fermentation system

With volatile solid content (VS) for benchmark, use preculture good seed sludge and organic solid castoff to be measured configure anaerobic fermentation system, for preventing organic solid castoff Middle nutrition material to be measured unbalanced and the anaerobic fermentation system wild effect caused, the interpolation mass ratio of inoculum and organic solid castoff to be measured is 2:1, whole anaerobic fermentation system occupies 70% of anaerobic fermentation vial total measurement (volume), the biogas that all the other volumes produce for collecting anaerobic fermentation, in order to eliminate the biogas of inoculum generation to the impact of net result, test arranges the blank not adding fermentation substrate, simultaneously in order to investigate the activity of inoculum, test arranges the positive control adding cellulose powder.All process all in triplicate above;

4) foundation of anaerobic environment system

Before lid bottle cap, in high-boron-silicon glass bottle, pass into high pure nitrogen, continue 2 minutes, to replace the air at head space place in bottle, form oxygen-free environment, then tighten bottle cap, carry out sealing, be placed in electric heating incubator and start to carry out anaerobic fermentation;

5) metering of gas volume and the mensuration of gas composition

Read the reading in accurate gas gauge every day, (standard atmospheric pressure under institute's measuring pressure being scaled the status of criterion by the equation of gas state, 0 DEG C) gas volume, and from anaerobism bottle, remove 2mL gas in headspace sampling bottle with injector for medical purpose, by gas chromatograph for determination biogas component.Until when aerogenesis slope of a curve goes to zero, stop test;

6) biochemical methane potentiality calculate

Biochemical methane potentiality (BMP) computing formula (Nml/gVS):

$\mathrm{BMP}(\mathrm{Nml}/\mathrm{gVS})=\frac{{\mathrm{\Σ}}_{i=1}^n[(\mathrm{Pi}\×V\×\mathrm{Ci}-\mathrm{Pj}\×V\×\mathrm{Cj})\÷101.325\×273\÷(273+T)]}{m}$

Pi: add gaseous tension in the anaerobism bottle of fermentation substrate, unit is kPa;

Ci: add methane concentration in the anaerobism bottle of fermentation substrate, unit is %;

Pj: do not add gaseous tension in the anaerobism bottle of fermentation substrate (blank), unit is kPa;

Cj: do not add methane concentration in the anaerobism bottle of fermentation substrate (blank), unit is %;

101.325: the air pressure number being 1 standard atmospheric pressure, unit is kPa.

T: anaerobic fermentation temperature, unit is DEG C;

M: be volatile solid (VS) quality of fermentation substrate, unit is g.

During test, magnetic agitation rotor is placed in high-boron-silicon glass bottle, connects metal airway, minimum gas pressure gauge and unidirectional gas valve, the sealing of bottleneck junction completely, is tightened bottle cap, is carried out line seal simultaneously.From minimum gas pressure gauge, regularly read the pressure of gas in fermentation flask, by the equation of gas state, by the volume of (1 atmospheric pressure, 0 DEG C) gas under the gaseous tension at head space place is scaled the status of criterion in fermentation flask.Regular use is connected to exhaust manifolds place containing the medical plastic syringe of T-valve, gathers the gas in fermentation flask, carries out the mensuration of gas composition with gas chromatograph.After getting depressed bundle, the gas in emptying bottle, to bottle internal and external pressure balance.

This device is used for the Methane production potential measuring wheat stalk and maize straw.

To take from the anaerobic sludge of sewage treatment plant of Gaobeidian City of Beijing mesophilic anaerobic digestion tank as inoculum, device of the present invention is utilized to implement method of the present invention.In this experiment, the initial pH value of inoculum is 7.65, and total solid (TS) content is 5.37%, and volatile solid (VS) content is %2.35 (calculating with wet basis), and VS/TS is 44.74%.Anaerobic ferment devices cumulative volume is 500mL, and fermentation system working volume is 350ml, and gas storage device working volume is 150ml.The concentration inoculated in fermentation system is 6gVS/L, and the concentration of substrate is 3gVS/L, all the other volumes tap water polishing.Fermentation system temperature is 37.0 ± 1.0 DEG C, and magnetic agitation rotating speed is 80r/min.Stalk and cellulose positive controls in the end get rid of the methane content that inoculum itself produces in result.

As shown in Figure 3, remove in this experiment wheat stalk and maize straw before inoculum cumulative methane output 595.32 ± 11.87mL/gVS and 651.58 ± 51.5mL/gVS respectively, the cumulative methane output of inoculum is 399.37 ± 16.3mL/gVS, and the cumulative methane output of cellulose positive control is 746.76 ± 20.97mL/gVS.After removing the cumulative methane output of inoculum, the cumulative methane output of wheat stalk, maize straw and positive control cellulose powder is respectively 195.96 ± 11.97mL/gVS, 252.21 ± 9.42mL/gVS and 347.39 ± 20.97mL/gVS.Positive control cellulose powder is 83.7% of its theoretical Methane production potential (415mL/gVS), and three parallel experiment medial error number percents are respectively 4.95,2.42% and 3.12%, and test effectively.Therefore, the biochemical methane potentiality (BMP) of wheat stalk and maize straw are respectively 195.96 ± 11.97mL/gVS and 252.21 ± 9.42mL/gVS.

Claims (3)

1. one kind measures the device of organic solid castoff biochemical methane potentiality, it is characterized in that: comprise electrothermostat cover, electrothermostat base, anaerobic ferment devices, magnetic agitation dish, temperature controller and magnetic agitation disk controller, electrothermostat cover is the bottomless glass box cover of rectangle, and top cover is provided with two Waste gas outlets; Electrothermostat base is rectangular closed box body, magnetic agitation dish is positioned on electrothermostat base, anaerobic ferment devices is located on magnetic agitation dish, and the sealing of electrothermostat cover is buckled on electrothermostat base, and temperature controller and magnetic force stir disk controller and is located in electrothermostat base; Anaerobic ferment devices is made up of high-boron-silicon glass bottle, sealing bottle screw cap, accurate gas gauge, metal airway, unidirectional gas valve, high-boron-silicon glass fermentation flask is sealed by seal bottle cap, two metal airways are vertically fixed on blend rubber pad and gastight adhesive on seal bottle cap respectively and seal, wherein a metal airway upper end is connected with accurate gas gauge and is provided with unidirectional gas trap, an other metal airway upper end is exhausr port and is provided with unidirectional gas trap, and magnetic agitation rotor is located at bottom high-boron-silicon glass fermentation flask.

2. measure the device of organic solid castoff biochemical methane potentiality according to claim 1, it is characterized in that: described anaerobic ferment devices quantity is 12-36.

3. utilize device described in claim 1 to measure a method for organic solid castoff biochemical methane potentiality, it is characterized in that step is as follows:

1) complete the connection of said apparatus, and airtight test is carried out to this device, be close to lid place sheathed catheter O type rubber ring, and seal with gastight adhesive;

2) inoculum is selected and pre-service

Select and the anaerobic sludge of the methane-generating pit of operational excellence close with organic solid castoff character to be measured as inoculum, and with the screen cloth in 1-2mm aperture, inoculum is filtered, then be positioned over preculture 5-10 days in the identical incubator of test fermentation temperature, activated sludge also consumes the nutriment in inoculum further;

3) configuration of anaerobic fermentation system

With volatile solid content (VS) for benchmark, use preculture good seed sludge and organic solid castoff to be measured configure anaerobic fermentation system, for preventing organic solid castoff Middle nutrition material to be measured unbalanced and the anaerobic fermentation system wild effect caused, the interpolation mass ratio of inoculum and organic solid castoff to be measured is set to 2:1, whole anaerobic fermentation system occupies the 60-75% of anaerobic fermentation vial total measurement (volume), the biogas that all the other volumes produce for collecting anaerobic fermentation, in order to eliminate the biogas of inoculum generation to the impact of net result, test arranges the blank not adding fermentation substrate, simultaneously in order to investigate the activity of inoculum, test arranges positive control, and positive control, according to fermentation substrate different in kind to be measured, arranges cellulose powder, and above all process all in triplicate,

4) foundation of anaerobic environment system

Before lid bottle cap, in high-boron-silicon glass bottle, pass into high pure nitrogen, continue 2-3 minute, to replace the air at head space place in bottle, form oxygen-free environment, then tighten bottle cap, carry out sealing, be placed into during electric heating is cultivated and start to carry out anaerobic fermentation;

5) metering of gas volume and the mensuration of gas composition

Reading in the accurate gas gauge of regular reading, (standard atmospheric pressure under institute's measuring pressure being scaled the status of criterion by the equation of gas state, 0 DEG C) volume of gas, and from anaerobism bottle, remove 2mL gas in headspace sampling bottle with injector for medical purpose, by gas chromatograph for determination biogas component.Until when aerogenesis slope of a curve goes to zero, stop test;

6) biochemical methane potentiality calculate

Biochemical methane potentiality (BMP) computing formula (Nml/gVS):

$\mathrm{BMP}(\mathrm{Nml}/\mathrm{gVS})=\frac{{\mathrm{\Σ}}_{i=1}^n[(\mathrm{Pi}\×V\×\mathrm{Ci}-\mathrm{Pj}\×V\×\mathrm{Cj})\÷101.325\×273\÷(273+T)]}{m}$

Pi: add gaseous tension in the anaerobism bottle of fermentation substrate, unit is kPa;

Ci: add methane concentration in the anaerobism bottle of fermentation substrate, unit is %;

Pj: do not add gaseous tension in the anaerobism bottle of fermentation substrate (blank), unit is kPa;

Cj: do not add methane concentration in the anaerobism bottle of fermentation substrate (blank), unit is %;

101.325: the air pressure number being 1 standard atmospheric pressure, unit is kPa;

T: anaerobic fermentation temperature, unit is DEG C;

M: be volatile solid (VS) quality of fermentation substrate, unit is g.