Potential Gas Production Research Articles

Yogurt and molasses can alter microbial-digestive and nutritional characteristics of pomegranate leaves silage

Fewer studies in recent years have been conducted on the nutritional potential and fermentation quality of silage prepared from pomegranate leaves (PL). So, we investigated the nutritional-fermentation quality of PL before and after ensiling with or without yogurt containing mainly lactic acid-producing bacteria (Lactobacillus bulgaricus and Streptococcus thermophiles) and molasses (at two levels of 2 and 4% of dry matter) in the polyethylene microsilos for 60 days. A range of dry matter (29.1–39.1%), crude protein (3.85–4.83%), ash (5.33–8.60%), and non-fiber carbohydrates (53.2%–58.6%) contents were observed among the treatments. A significant increase in calcium, potassium, magnesium, manganese, iron, and zinc was observed in PL after ensiling compared to before ensiling (p < 0.05). The PL ensiled with 4% yogurt exhibited the highest ammonia nitrogen, lactic and acetic acids, but the lowest butyric acid among the ensiled PL (p < 0.05). The ensiling of PL without additive (control) significantly decreased potential gas production, dry matter digestibility, organic matter digestibility, total volatile fatty acids, metabolizable energy, net energy for lactation, base-buffering capacity, titratable alkalinity, and acid–base buffering capacity compared to before ensiling (p < 0.05). According to the present results, the nutritional value of PL before ensiling was higher than after ensiling. The addition of yogurt and molasses to PL at the ensiling process especially at 4% of dry matter, improved the fermentation and nutritional characteristics. In general, the addition of yogurt or molasses as two cheap and available additives is recommended to improve the digestive-fermentation parameters of PL in silo and ruminal environments.

Organic matter composition and greenhouse gas production of thawing subsea permafrost in the Laptev Sea

Subsea permafrost represents a large carbon pool that might be or become a significant greenhouse gas source. Scarcity of observational data causes large uncertainties. We here use five 21-56 m long subsea permafrost cores from the Laptev Sea to constrain organic carbon (OC) storage and sources, degradation state and potential greenhouse gas production upon thaw. Grain sizes, optically-stimulated luminescence and biomarkers suggest deposition of aeolian silt and fluvial sand over 160 000 years, with dominant fluvial/alluvial deposition of forest- and tundra-derived organic matter. We estimate an annual thaw rate of 1.3 ± 0.6 kg OC m−2 in subsea permafrost in the area, nine-fold exceeding organic carbon thaw rates for terrestrial permafrost. During 20-month incubations, CH4 and CO2 production averaged 1.7 nmol and 2.4 µmol g−1 OC d−1, providing a baseline to assess the contribution of subsea permafrost to the high CH4 fluxes and strong ocean acidification observed in the region.

Compositions, structures, and confined pyrolysis of the alga Chlorella and its nonhydrolyzable fractions

Nonhydrolyzable organic carbon (NHC) fractions were isolated from commercial Chlorella using trifluoroacetic acid (TFA), sodium periodate (SP), ball mill (MES), and ball mill-sodium periodate (BSP) methods. The structures and relationships of the fractions with oil and gas production potentials (OGP) were investigated by solid-state 13C Cross Polarization/Total Sideband Suppression (CP/TOSS) NMR spectroscopy techniques and by confined pyrolysis. The results demonstrated that the TFA and SP fractions exhibited the highest polymethylene carbon contents and the lowest proportions of polar materials. Both bulk Chlorella and the NHC fractions had considerable oil and gas generation potential. The hydrogen indices evaluated by Rock-Eval analysis were highly significantly correlated with the OGP values estimated for the NHC fractions from the NMR methods. In addition, the oil and gas generated from the Chlorella sample and its NHC fractions were dominated with primary pyrolysis products. The contents of total n-alkanes (n-C6–33) of the pyrolysates increased with increasing pyrolysis times. The n-alkanes of the TFA, SP, and BSP fraction pyrolysates were dominated by mid chain-length components (n-C15, n-C17, and n-C23). Moreover, the SP fraction exhibited high NHC yield and OGP value, and low contents of nitrogen and oxygen. This study significantly improves our understanding of the bio-oil generation potential of this green alga.

Assessment of organic acid salts on fermentation quality, aerobic stability, and in vitro rumen digestibility of total mixed ration silage.

The work aimed to investigate the effects of four organic acid salts on fermentation quality, aerobic stability, and in vitro rumen digestibility of total mixed ration (TMR) silage prepared with citric acid residue, wet brewers' grains, and Napier grass. The TMR was ensiled with the following: (1) no additives (control), (2) 0.1% sodium benzoate (SB), (3) 0.1% potassium sorbate (PS), (4) 0.5% sodium diacetate (SDA), (5) 0.5% calcium propionate (CAP) on a fresh weight basis. All silos (10 L) were opened after 60days of ensiling to determine fermentation profiles and in vitro rumen digestibility, and then were subjected to a 9-day aerobic stability test. Four organic acid salts significantly (p < 0.05) increased dry matter contents, lactic acid bacteria count, and decreased ethanol content and yeast count compared with the control. The SDA and CAP significantly (p < 0.05) increased water-soluble carbohydrates, lactic acid, and crude protein contents, and decreased pH, ammonia nitrogen, neutral detergent fiber, and hemicellulose contents compared with other TMR silages after 60days of ensiling. Organic acid salts significantly (p < 0.05) prolonged the hours of aerobic stability and significantly (p < 0.05) increased cumulative gas production and potential gas production compared with the control. The treatments of SDA and CAP significantly (p < 0.05) improved aerobic stability as indicated by higher (p < 0.05) lactic acid and water-soluble carbohydrates contents, and lower (p < 0.05) pH, ammonia nitrogen, ethanol contents, and yeast count compared with the control. The treatments of SDA and CAP significantly (p < 0.05) increased in vitro rumen parameters, as indicated by higher (p < 0.05) in vitro digestibility of dry matter, crude protein, and neutral detergent fiber after 60days of ensiling. Overall, these results indicated that the addition of SDA and CAP could ensure the good fermentation quality and improve aerobic stability of TMR silages. By comprehensive consideration, CAP was recommended for improving fermentation quality, aerobic stability, and in vitro rumen digestibility of TMR silages prepared with wet brewers' grains, citric acid residue, and Napier grass.

Prediction of gas production potential based on machine learning in shale gas field: a case study

ABSTRACT Productivity prediction is an important aspect of oil and gas exploration and development. As the amount of field data has increased, traditional engineering methods have begun to face challenges. The prediction of shale gas well production is influenced by geological, drilling, and completion characteristics. The relationship between variables is highly nonlinear and non-intuitive. In this study, 384 production well data were collected, including 14 input features and one output feature, with a total of 5,760 data points, 80% of which were used for training processes and 20% for testing processes. Four machine learning methods, namely an extreme gradient lifting tree, random forest, artificial neural network and support vector machine, were used to construct a shale gas well productivity prediction model. It was found that the machine learning method could accurately can well reflect the nonlinear relationship between the influencing factors and productivity. After the data were entered into the model training, regression evaluation indexes, such as the determination coefficient R2, were used for measurement. Compared with other models, the support vector machine regression model with gamma (kernel coefficient) and C (punish coefficient) values of 1 and kernel function as the radial basis function have smaller errors. The mean absolute, mean square, and root mean square errors were 0.062, 0.006, and 0.077, respectively. The R2 values for the training and testing sets were 0.861 and 0.843, respectively. The results indicated that the prediction accuracy of the support vector machine regression model is higher, and the accuracy of the training set reached 86%. The productivity prediction method we provide has a good guiding significance for other gas well productivity predictions while greatly reducing the uncertainty of gas field development and production.

EFECTO ADITIVO DE ENSILADOS DE POLLINAZA, CERDAZA Y UREA MEZCLADOS CON MELAZA DE CAÑA Y SUBPRODUCTO DE PANADERÍA EN DIETAS PARA CORDEROS

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;The use of silages from non-conventional sources of nitrogen and soluble carbohydrates in feeding lambs is controversial in terms of nutrient supply; due to the minimum number of studies reported to date of &lt;em&gt;in vitro&lt;/em&gt; evaluations that allow measuring its nutritional value in ruminants. &lt;strong&gt;Objective:&lt;/strong&gt; To evaluate the additive effect and fermentation potential of silages plus concentrates in diets for lambs on the &lt;em&gt;in vitro&lt;/em&gt; gas production kinetics. &lt;strong&gt;Methodology:&lt;/strong&gt; Six diets (silage + concentrate) were evaluated in a factorial arrangement of 3 N sources (dried poultry litter, fresh swine manure, agricultural urea) × 2 carbohydrate sources (sugar cane molasses, bakery by-product). The diets contained: a) silage (400 g/kg DM) and b) concentrates (600 g/kg DM) based on soybean meal, ground corn, wheat bran, corn stover, fish meal, and vitamin and mineral premix. Average gas production data were analyzed with PROC MIXED and the gas production curves were fitted into the Exponential Logistic model with PROC NLMIXED. &lt;strong&gt;Results:&lt;/strong&gt; The PO+MC (151.87 mL/gas MS) and CF+MC (153.12 mL/gas MS) treatments had higher average gas production during incubation. An additive effect was observed on the maximum asymptote of gas production in the CF+MC (+ 4.26%) and PO+MC (+ 3.75%) diets (&lt;em&gt;P&lt;/em&gt;&amp;lt;0.01). Diets based on PO or CF combined with MC and SPP had higher IVDMD, IVOMD, and IVNDFD than the control treatment (UR). &lt;strong&gt;I&lt;/strong&gt;&lt;strong&gt;mplications: &lt;/strong&gt;The inclusion in diets for growing lambs of corn stover silage based on rapidly fermentable carbohydrate sources with non-protein nitrogen from pig and poultry excreta in diets for growing lambs has associative effects on nutrient degradability and its fermentation potential in small ruminant feed. &lt;strong&gt;Conclusions:&lt;/strong&gt; The PO+MC treatment has a higher potential for gas production due to the associative effect of its components. &lt;/p&gt;

Chemical, mineral composition, in vitro ruminal fermentation and buffering capacity of some rangeland-medicinal plants

A diverse group of rangeland-medicinal plants are being used by ruminant whilst some of them have not been assessed for their nutritional value. This study was aimed to evaluate the chemical and mineral composition, buffering capacity, and in vitro fermentation of some rangeland-medicinal plants including Thymus kotschyanus, Ziziphora persica, Lallemantia royleana, and Scutellaria litwinowii in the family Lamiaceae, and Hypericum scabrum, in the family Hypericaceae. The results indicated that crude protein (CP) content ranged from 8.66% (S. litwinowii) to 12.17% of DM (H. scabrum). It was found that Z. persica had the highest potential gas production, metabolism energy (ME), relative feed value (RFV), and dry matter digestibility (DMD) values of 53.44 (mL 200-1 mg DM), 5.84 (MJ kg-1 DM), 170.66 and 70.88%, respectively. Mineral content differed among plants; Ca ranged from 5.79 to 41.96 g kg-1 DM. The concentrations of Ca, K, Mg, Fe, Zn, and Co were highest for L. royleana. Total volatile fatty acids (TVFA) and propionate concentrations were highest in the culture medium cultured with Z. persica, however, acetate, and butyrate were highest in H. scabrum. Acid-base buffering capacity was lower in T. kotschyanus and H. scabrum compared to other plants, while it was higher in S. litwinowii. Overall, it can be concluded that among plants evaluated in this study, Z. persica had higher nutritional value for sheep feeding.

Effect of moringa foliage supplementation on in vitro ruminal gas production kinetics and substrate degradation in cattle

This study explored the influence of moringa (Moringa oleifera; MO) foliage supplementation on in vitro ruminalgas production kinetics and substrate degradation in cattle. In vitro fermentation study was carried out with twotypes of substrates, viz. wheat straw (WS) and WS plus concentrate mixture (CM; 60:40) in cattle rumen inoculum.The MO was incorporated to both the substrates at 0, 5, 10, 20, 30, 40 and 50% levels of total dry matter. Thesubstrates were incubated up to 24 h and substrate degradation was measured. The in vitro gas production kineticswas performed with 8 different (0, 5, 10, 20, 30, 40, 50 and 100%) levels of MO with WS substrate and incubatedat 0, 3, 6, 9, 12, 24, 36, 48 and 72 h. The MO addition increased the total gas volume (ml/200 mg) up to 50% level,though, it was analogous when WS and CM based substrate was used. The truly degradable organic matter in rumen (TDOMR) was increased with MO supplementation from 10% onwards. The microbial biomass production (MBP) and partitioning factor (PF) were higher on 30% onwards MO levels. Addition of MO increased the gas production at 24 h from 30% onwards, however, cumulative gas production at 72 h was higher in control (CON). The potential gas production (b) was higher for CON than MO substrates. Fractional rate of fermentation (c) increased from 10 to 100% MO levels. The half time (t1/2) of gas production was substantially reduced with MO supplementation. The volume of gas at t1/2 was significantly lower at 30%. TDOMR was analogous amongst the treatments, however, MBP and PF were higher at 30% level relative to 10 and 20% MO levels. Hence, it may be deduced that supplementation of moringa foliage to cereal straw-based substrate considerably improved the gas production, fractional rate of fermentation, TDOMR, MBP and PF in cattle inoculum.

Hydrocarbon Gases in Seafloor Sediments of the Edge Shelf Zone of the East Siberian Sea and Adjacent Part of the Arctic Ocean

The continental margins of the East Siberian Sea and Arctic Ocean are among the Earth’s most inaccessible marine environments for hydrocarbon research due to the almost year-round presence of ice cover. Despite this, limited preliminary assessments which have been carried out to date have all yielded some indication of high oil and gas production potential in these regions. This article presents the results of gas-geochemical studies of seafloor sediments of the East Siberian Sea, obtained in three expeditions onboard the R/V “Akademik Lavrentiev” in 2008 (LV45), 2016 (LV77), and 2020 (LV90). The composition of sorbed hydrocarbon gases in seafloor sediments was analyzed. In addition, the stable isotopic composition of carbon was determined for CH4, C2H6, and CO2 in gases, which were desorbed from marine sediments. The sediments were also analyzed for organic matter content. Despite the absence of observable gas seepage directly into the water column, at some stations, increased concentrations of methane and hydrocarbon gases were encountered, indicating the widespread predominance of thermogenically derived gases. We present a hydrocarbon classification system which delineates eight identifiable sources of regional gas occurrences (coal gas, igneous rocks, solid bitumen, condensate-gas, gas-condensate, oil gas, gas oil, and oil gases). A stable isotopic analysis of carbon in CH4, C2H6, and CO2 indicates varying degrees of mixing between a shallow, early-kerogen gas source and a deeper mantle carbon source in some areas of the study.

Optimal design of the field hydrate production test in the offshore India: Insights from the vertically heterogeneous hydrate reservoir model

Recently, the hydrate-bearing sand reservoirs were founded with high saturation in the offshore India by the National Gas Hydrate Program Expedition 02 (NGHP-02). Based on the detailed geological data at the NGHP-02-16 site, a more realistic reservoir model is constructed to analyze the unique multiphase flow and hydrate phase change behaviors from the geologically descriptive hydrate reservoirs. The main goals of this work are to optimize the adjustable production parameters and to predict the long-term gas production performance for guiding the upcoming field hydrate production test in India. The results indicate that gas production rates increase, but water production rates decrease slowly with time from the heterogeneous hydrate-reservoir. This is completely different from the previous prediction of multiphase flow behavior based on homogeneous hydrate-reservoir models. A non-uniform hydrate dissociation front is formed in the hydrate-reservoir due to the reservoir heterogeneity promote the horizontal dissociation of solid-hydrate within the high permeability sand layers. The maximum distance of free gas zone expands to outside more than 500 m from the production well. This indicates that the field fault system should be carefully concerned during the long-term production. Sensitivity analysis results suggest that the complete perforation in the hydrate-bearing layer and the underlying water saturated layer is beneficial for improving the hydrate production performance. Over the 5 years depressurization, a total of 2.08 × 107 ST m3 methane gas can be produced using the recommended well placement. The average gas-to-water ratio and energy ratio reach 10.22 ST m3 CH4/m3 H2O and 30.14, respectively, showing a high gas production potential from this hydrate site.

Effects of wet brewers grains on fermentation quality and in vitro ruminal digestibility of mixed silage prepared with corn stalk, sweet potato peel and dried apple pomace in southeast China.

The effects of wet brewers grains (WBG) on fermentation quality, chemical composition and in vitro ruminal digestibility of mixed silages prepared with corn stalk, dried apple pomace and sweet potato peel were evaluated. A mixture of corn stalk, sweet potato peel and dried apple pomace (50/30/20) was ensiled with 0, 10%, 20% and 30% WBG on a fresh weight (FW) basis for 1, 3, 5, 7, 14 and 30 days respectively. The results showed that the application of WBG increased (p < 0.05) lactic acid, acetic acid and total volatile fatty acids contents, and decreased (p < 0.05) pH, dry matter, water-soluble carbohydrates content and ammonia-nitrogen/total nitrogen during ensiling. The pH in all silages was below 4.03 during ensiling. Treating with WBG increased (p < 0.05) crude protein content, and decreased (p < 0.05) neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose content after 30 days of ensiling. After 72 h of incubation, cumulative gas production, potential gas production and in vitro crude protein digestibility increased (p < 0.05) with the increasing proportions of WBG. However, in vitro digestibility of dry matter and neutral detergent fibre, and metabolisable energy were similar in all silages. The 20% and 30% WBG-treated silages showed better fermentation quality and greater or higher in vitro digestibility, which were indicated by greater or higher (p < 0.05) lactic acid content, in vitro crude protein digestibility, and lower (p < 0.05) pH, ammonia-nitrogen/total nitrogen ratio as compared with the control. Therefore, ensiling agro-food by-products with at least 20% WBG were recommended for improving fermentation quality.

An optimal selection method of wells for secondary fracturing in a single coal seam and its application

At present, methods including mathematical modeling, physical or numerical simulation, and in-situ monitoring have been generally adopted to determine evaluation parameters for coalbed methane (CBM) wells for secondary fracturing. These conventional methods either entail many assumptions, or some parameters are difficult to obtain, resulting in a certain deviation between the evaluation results and reality, or the application cost is high, preventing the monitoring of each CBM well. In view of this, an evaluation index system for the gas production potential, effective length of cracks formed by fracturing, and supporting length of proppant in cracks was established based on the system theory. The evaluation indices were characterized through production data, such as logging, fracturing and drainage, which could avoid potential bias in evaluation when only considering a certain parameter and ensured accuracy and practicability of the evaluation parameters for each well. Principal component analysis (PCA) and the entropy weight method (EWM) were used to obtain weights of evaluation parameters, which avoided the contradiction of contributions of various parameters to optimal selection and the rationalized results. In this way, a method for step-wise optimal selection of wells for secondary fracturing integrating construction of evaluation parameters, determination of critical values, and entropy evaluation was proposed. The results of an evaluation of the Shizhuang South Block of Qinshui Basin (Shanxi Province, China) indicate that wells whose three evaluation indices are satisfied are most preferable; wells that only meet the effective length of cracks formed by fracturing or effective supporting length of proppant in cracks can be selected; wells which do not meet the gas production potential or all of the three parameters cannot be selected.

Effects of Graded Levels of Mimosa (Acacia mearnsii) Tannin Purified with Organic Solvents on Gas, Methane, and In Vitro Organic Matter Digestibility of Eragrostis curvula Hay.

Simple SummaryEnteric methane emission serves as one of the major contributors to global warming, and is responsible for the loss of an appreciable amount of dietary energy. Utilization of Mimosa tannin in reducing methane yield in ruminants is well documented. However, its supplementation in large amounts affects rumen fermentation and digestibility, attributed to the presence of a high number of hydrolysable tannins and other non-tannin substances, which poison rumen microorganisms. Purification might remove the toxic compounds, thereby decreasing the methane without affecting the digestibility of the diet. In this study, mimosa tannin was purified with organic solvents (ethyl acetate and pentanol) using the Soxhlet extraction method, and the influence of different concentrations (10, 20, 30, and 40 g/kg DM) of the purified tannins on gas, methane, and in vitro organic matter digestibility of Eragrostis curvula hay were evaluated in comparison with the same levels of unpurified tannin. The addition of lower levels of ethyl acetate and pentanol purified mimosa tannin extracts reduced in vitro gas and methane production without adverse effects on dry matter digestibility.The higher contribution of methane (CH4) to global anthropogenic potential is a cause of concern to livestock producers. Mimosa tannin gained recent acceptance as an additive for enteric CH4 mitigation. However, rumen fermentation and digestibility are compromised when large quantities of tannins are supplemented due to the presence of hydrolysable tannin and other non-tannin molecules in mimosa extract, which are toxic to animals. Purification could eliminate the toxins, and thus, reduce the CH4 yield without negative effects on rumen microbial activities and organic matter degradation. The Soxhlet extraction method was used to purify the tannin using organic solvents (ethyl acetate and pentanol). The unpurified, ethyl acetate purified, and pentanol purified tannins at the dosages of 10, 20, 30, and 40 g/kg DM of substrate (Eragrostis curvula hay) were evaluated for gas, CH4, and in vitro organic matter digestibility (IVOMD) in comparison with substrate alone. Gas kinetics were tested using a simple exponential model with lag. The results showed that compared with control, gas, CH4, IVOMD, CH4/gas, CH4/IVOMD, gas/IVOMD, asymptotic gas volume (v), and rate of gas production (k) decreased (p < 0.01) linearly with the increase in the inclusion levels of all tannin extracts. Also, ethyl acetate purified and pentanol purified tannin extracts reduced gas and CH4 at lower dosage (30 g/kg DM) compared to unpurified tannin extract at a higher level (40 g/kg). Pentanol purified tannin was more effective at lower dosage (20 g/kg DM) in terms of CH4/gas and CH4/IVOMD. It was concluded that the purification of mimosa tannin with ethyl acetate and pentanol reduced potential gas production and CH4 without much reduction in substrate digestibility when up to 30 g/kg DM of feed was used. Lower inclusion levels of ethyl acetate and pentanol purified extracts could give a similar result with a higher dosage of unpurified tannin.

Effects of brewers’ spent grains on fermentation quality, chemical composition and in vitro digestibility of mixed silage prepared with corn stalk, dried apple pomace and sweet potato vine

The experiment was conducted to evaluate the effects of brewers’ spent grains (BSG) on the fermentation quality, chemical composition and in vitro parameters of mixed silage prepared with corn stalk, dried apple pomace and sweet potato vine. In the experiment, a ternary mixture of corn stalk, sweet potato vine and dried apple pomace (50/30/20) was ensiled with 0%, 10%, 15% and 20% BSG on a fresh weight (FW) basis for 1, 3, 5, 7, 14 and 30 days, respectively. The application of BSG significantly (p<.05) increased lactic, acetic and total volatile fatty acids content, and significantly (p<.05) decreased pH, lactic acid/acetic acid, ammonia nitrogen, dry matter and water-soluble carbohydrates content during ensiling. None or tiny amounts of propionic and butyric acid were detected in all silages. Compared with the control, higher (p<.05) Flieg points, crude protein content and lower (p<.05) neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose content were found in BSG-treated silages on day 30 of ensiling. After 72 h of incubation, the application of BSG significantly (p<.05) increased the cumulative gas production, potential gas production, in vitro dry matter, crude protein digestibility and metabolisable energy. The 20% BSG silages had better fermentation quality and higher in vitro digestibility, as indicated by higher lactic acid content, in vitro dry matter, crude protein digestibility, metabolisable energy, lower pH, and lower ammonia nitrogen content than other silages. The application of 20% BSG was recommended to ensure good quality silages. Highlights Ensiling in the form of mixed silages is a good way to consume largely agro-food by-products. Reducing the energy waste and environmental pollution caused by high-quantity agro-food by-products. 20% brewers’ spent grains application had positive effects on in vitro parameters.

Study of the influence of exogenous fibrolytic enzyme additive on chemical composition, fermentation characteristics, and nutritional value of brewer's spent grain.

This study explores the influence of different doses of two exogenous fibrolytic enzyme (EFE) additives (liquid (EFE1: 1, 2, and 4 μΙ/g DM (dry matter)) and powder (EFE2: 1, 2, and 4 mg/g DM)) on the chemical composition, fermentation characteristics, and nutritional value of brewer's spent grain (BSG). The results indicate that EFE1 at low doses does not affect the chemical composition, fermentation characteristics, and the nutritional value of BSG. The medium dose EFE1 decreases the fiber compound but increases the nonfiber carbohydrates (NFC) and soluble dry matter. Also, this dose modified the fermentation of BSG by increasing the amount of gas and its fermentation rate and decreasing the time between the inoculation and start of fermentation. Therefore, it increases the digestibility, metabolizable energy, net energy‐lactation (NEL), total volatile fatty acids, and the microbial crude protein production of BSG. The high dose of EFE1 decreases the fiber compound and increases the nonfiber carbohydrates and soluble dry matter; however, it also decreases the potential of gas production and does not affect the nutritional value of BSG. For EFE2, all the doses do not modify the chemical composition, fermentation characteristics, and the nutritional value of BSG. These results suggest that the effectiveness of EFE varied, depending on the type of EFE and dose. Increase in the nutritional value of BSG by EFE1 at the medium dose can encourage breeders to use these wastes as feed at low cost in cow nutrition.

The potential of frozen rumen fluid for ruminant feed evaluation using in vitro gas production technique

The aim of this study was to determine the potential of frozen rumen fluid (RF) for ruminant feed evaluation using in vitro gas production (IVGP) technique. This study used a factorial randomized block design with a 3 × 3 × 3 pattern, consisting three feeding regimes varying in forage to concentrate proportion, namely 20%:80% (feed A), 40%:60% (feed B), and 60%:40% (feed C), respectively; three storage time (2, 11, and 19 days); and RF from 3 breeds of indigenous cattle, namely Bali, crossbred Ongole and Madura cattle as groups. The results showed that the effects of feeding regimes, inoculum source, or storage time on total gas production, potential of gas production, rate of gas production, dry matter and organic matter degradability. Based on the results, it can be concluded that frozen RF may be used as inoculum source for feed evaluation using the IVGP technique and hence it supports the previous findings reported in the literature. Considering that the effects of different feeds, inoculum sources, and storage times gave the specific values, it is advisable that to use RF from slaughtered animals should be taken from the same breed to allow accurate comparison for feed evaluation using IVGP technique.

Reservoir characteristics and gas production potential of deep coalbed methane: Insights from the no. 15 coal seam in shouyang block, Qinshui Basin, China

Considering the large burial depth and unclear coalbed methane (CBM) development potential of the No. 15 coal seam in the Shouyang block in the northern Qinshui Basin, this study investigated the characteristics and gas production capacity of deep CBM reservoirs in the No. 15 coal seam based on the analysis of geological characteristics of CBM and the simulation of CBM production capacity. The No. 15 coal seam has a large thickness, strong adsorption capacity, medium gas content, low critical desorption pressure, low reservoir pressure, and a low ratio of critical desorption pressure to reservoir pressure (also referred to as the ratio). Based on the reversible relationship between the adsorption and desorption of CBM, we established an equation expressing the relationship between the gas content and burial depth of the No. 15 coal seam using massive data from gas content tests, isothermal adsorption experiments, and well tests. The analyses of main factors controlling the permeability of deep reservoirs of the No. 15 coal seam and their differences with those of shallow reservoirs indicate that deep CBM reservoirs have significantly low permeability owing to their large burial depth and high in-situ stress despite their favorable coal structure and well-developed fractures. Moreover, this study predicted the gas production characteristics of the No. 15 coal seam through numerical simulations of CBM drainage. The simulation results were similar to the actual gas production results, indicating that the No. 15 coal seam has great gas production potential. The results of this study will provide geological support for predicting the gas content and assessing the development potential of the No. 15 coal seam in the deep part of the northern Qinshui Basin.

Bio methane potential of sludge from municipal sewer and exchange stations

Technologies with resource recovery alternatives are suggested in metropolitan settings. Anaerobic digesters (AD) are the most common. The use of microcrystalline cellulose and a variety of grocery products as control feed increases the cost of bio methane potential analysis (BMP). This limits its replication, especially in developing countries. As a result, this study looks into the use of milled paper as a control feed during BMP analysis of sludge from sewer and exchange stations.A batch experimental study at 37 °C with hydraulic retention times of 23 and 24 days for exchange station and sewage sludge, respectively, was established for the assessment. The pH of the sewage sludge was acidic during the analysis. To avoid underestimating the total (TS) and volatile solid (VS) ratios, the VS should indeed be determined through temperature or pH adjustment. As a result, the preceding alternative was implemented in this work.According to the findings of the online biogas application, the blank (milled paper) accurately keeps the required validation standards. Furthermore, the gas production potential of sludge from the exchange station (ES) and the sewage line (SS) is 2.4 and 1.6 NL/gVs, respectively. The generated gas has an electric potential of 8.81 and 3.35 KWH for ESS and SS, respectively. Interestingly, the calorific values of the investigated substrates were also nearly equivalent.In brief, using milled paper as a control feed in BMP analysis reduces laboratory costs and encourages BMP test repetition, which is especially important in developing countries. This advances research on the use of AD in the search for alternative energy sources.

POTENSI PRODUKSI BIOHIDROGEN DARI LIMBAH BIOMASSA PADA PROSES PENCERNAAN ANAEROBIK

The sustainability of hydrogen as an energy carrier depends on the production process and the source of raw materials. The choice of substrate in anaerobic digestion process plays an important role to maximize biohydrogen production because it depends on its availability and the composition of substrate. The purpose of this study is to design and construct a prototype reactor for biohydrogen production and to determine the potential of H2 gas production from anaerobic digestion process. This study uses an experimental research method with three operating temperature variations in the reactor, at the range of thermophilic temperatures, i.e. 55°C, 60°C, and 65°C. The substrate used was POME and cow dung, and the process was conducted in 24 hours which is assumed to be the stage of non-methanogenic within the anaerobic process. From this research, the prototype of continuous stirred tank reactor (CSTR) in batch system was made from acrylic, with a capacity of 6 liters biomass waste. Using the reactor, total biohydrogen gas produced during 24 hours process with cow manure as substrate was 0,0932 gram at 55°C; 0,0307 gram at 60°C and 0,0797 gram at 65°C. While, biohydrogen production using POME as substrate was 0,0645 gram at 55°C; 0,1708 gram at 60°C, and 0,0636 gram at 65°C. These results indicate the potentiality of POME and cow manure to produce biohydrogen gas during anaerobic digestion process.

Chlorophyll changes during anaerobic digestion of cabbage waste

ABSTRACT To study the changes in the contents of chlorophyll a and chlorophyll b in cabbage waste during anaerobic digestion, two types of leafy cabbage waste were treated by fermentation, and the relationship between the degradation of chlorophyll a and chlorophyll b in cabbage waste and gas production potential during anaerobic digestion was analyzed using an anaerobic batch fermentation unit maintained at a constant temperature of (35 ± 1) °C. The results showed that, following anaerobic digestion, the gas production rates of common cabbage, Chinese cabbage, and mixed cabbage were 36 mL/g, 33 mL/g, and 27 mL/g, respectively. The total solids (TS) gas production rates were 838 mL/g, 774 mL/g, and 549 mL/g, respectively, whereas the volatile solids (VS) gas production rates were 1061 mL/g, 1134 mL/g, and 636 mL/g. During the biogas fermentation process, the content of chlorophyll a in each type of cabbage waste was consistently higher than that of chlorophyll b. Moreover, chlorophyll degradation correlated with daily gas production. Among the cabbage waste types analyzed, mixed cabbage had the highest chlorophyll a and chlorophyll b degradation rates of 81.71% and 99.08%, respectively, compared to that of common cabbage or Chinese cabbage alone. These findings extend the current knowledge on anaerobic fermentation treatment of cabbage waste.