Search or ask a question
Pricing
Login
Sign up
Home
Notebook
BETA
Literature Review
Copilot
Citation generator
Paraphraser
AI Detector
Chrome Extension
Talk with us
Use on ChatGPT
All figures (19)
Figures 3.11 and 3.12 show the pattern in the production of biogas from microwave treated maize straw. Biogas production increased from the day of the first measurement untill around the 16th day for both pretreatment conditions. Production then stabilised for the following week before it started falling around the 24th day. The samples that were treated for four minutes yielded the highest amount of biogas with a sum total of 539.46mL which is an increment of 208% compared with that of the raw maize straw. The samples pretreated for two minutes had a biogas production of 514.07mL of methane. This represents a 194% increase in biogas output with respect to the raw samples. Biogas
Table 2.3 summarizes typical physicochemical characteristics of cattle manure obtained from previous works. Table 2. 3 Physicochemical properties of cattle manure.
Table 1.7: Acid and alkaline pretreatment methods for lignocellulosic feedstock
Fig. 3.21 portrays the effects of sodium hydroxide pretreatment on biomethane production from cattle manure taken as the average amount of biogas produced by samples from each pretreatment condition i.e. the concentration of the basic solutions. It also highlights the effectiveness of different pretreatment conditions that were applied on the cattle manure. It can be seen that the pretreatment condition which led to the highest biogas production was the 0.3M NaOH solution with a maximum daily output of
Figure 3.4 shows the relation between the reducing sugar production and cumulative biogas production from untreated and pretreated cattle manure. It can be seen that both
Table 3.8 shows the effects of liquid hot water treatment on methane yield from maize straw. This pretreatment method was very effective in eliminating the resistance posed by lignin, cellulose and hemicellulose for maize straw as it produced relatively high amounts of biogas when compared to other pretreatment methods and the untreated maize straw samples. It is also a very economically feasible and environmentally friendly method because it does not involve the purchase, handling and disposal of chemicals that are both costly and potentially harmful to the environment. Liquid hot water pretreatment does not lead to the production of inhibitory by products. Biogas production showed a steady rise within the first two weeks until it reached maximum production after three
Figure 2. 2 Standard curve for the determination of reducing sugar using the Miller method.
Table 3.11 shows the biogas production values from cattle manure treated with heat assisted alkaline solutions. Measurements were carried out daily and sometimes in two
Table 3.9 and figure 3.17 show the comparisms between the biogas produced by the various pretreatment methods applied on maize straw in this study.
Table 3.4 shows the effects of pretreatment on the solubility of cattle manure. It can be seen that the pretreatment condition which produced the highest amount of reducing sugars was 0.3M H2SO4 with total concentration of 198mg/g biomass representing an increase of about 254% while the pretreatment condition with the relatively lowest soluble sugar production was the liquid hot water 105oC producing an average concentration of 77mg/g biomass which represents an increase in solubility of about 38%. Generally, both chemical pretreatments produced relatively higher amounts of soluble sugar compared to the raw sample. Physical pretreatments also proved to be very effective in increasing solubility of cattle manure. Microwave pretreatment was the most effective physical pretreatment method producing more than three times the amount of soluble sugar produced by the untreated samples. Liquid hot water pretreatment was also very effective; except for the samples treated at a temperature of 105oC, the amount of sugar produced was more than double that of the raw manure samples. This suggests that solubility of cattle manure also increases when the temperature is raised i.e. Higher
Fig. 3.14 represents the effects of liquid hot water treatment on biogas production from maize straw. It shows daily amounts of biomethane produced by the samples treated at different temperatures. The graph shows that the samples treated at 135oC had the highest daily biogas production with its maximum production of 49mL/d occurring on the 22nd day while the maximum production for the samples treated at 120oC was 48.4mL/d occurring on the 26th day. The samples treated at 105oC had a maximum production of 36.5mL/d on the 24th day. The overall biogas production lasted about 34 days for all pretreatment conditions which is about one week longer than the raw straw. The reason is probably because heating at high temperatures and pressure broke the glycosidic bonds between cellulose molecules and the bridges between lignin and cellulose/hemicellulose. It might also have been as a result of solubility of the biomass which made available more
Figure 2. 2 Standard curve for the determination of reducing sugar using the Miller method.
Figure 2. 2 Standard curve for the determination of reducing sugar using the Miller method.
Table 3.12 shows the amount of biogas produced from cattle manure after pretreatment in a microwave. Daily measurements were done using a manometer to determine the pressure exerted by the biogas produced each day. The microwave pretreatment of cattle manure proved to be very effective producing high daily and cumulative biogas concentrations when compared to untreated cattle manure and other pretreatment
Table 1.6: Selected physical pretreatment methods for lignocellulosic feedstock used in biogas production.
Table 2.1 gives a summary of typical physicochemical characteristics of maize straw obtained in previous studies.
Fig. 3.21 portrays the effects of sodium hydroxide pretreatment on biomethane production from cattle manure taken as the average amount of biogas produced by samples from each pretreatment condition i.e. the concentration of the basic solutions. It also highlights the effectiveness of different pretreatment conditions that were applied on the cattle manure. It can be seen that the pretreatment condition which led to the highest biogas production was the 0.3M NaOH solution with a maximum daily output of
Table 3.7 shows the biogas production values for lignocellulosic maize straw that has been treated in a microwave oven. Measurements were done daily using the manometer to determine the pressure exerted by the biogas produced each day. The microwave pretreatment was one of the most potent methods for maize straw pretreatment. Biogas production was relatively higher from day one when compared to other pretreatment methods and the untreated maize straw samples. It increased rapidly within the first two weeks until it reached maximum production after around 20 days. The production then
Table 3.13 shows the daily and cumulative amounts of biogas produced from cattle manure after pretreatment with liquid hot water. The quantity of biogas yield was quantified daily by using a manometer to determine the pressure exerted by the biogas produced. This pretreatment method proved to be more effective as temperature increased. The cumulative and daily biogas productions for the two pretreatment conditions (120oC and 135oC) were relatively high. Biogas increased rapidly within the first two weeks until it reached maximum production around the 20th day for both pretreatment conditions. Biogas production then started falling in a gradual manner until it ceased after a total time of about 32 days. The everyday biogas production is shown on the graph in figure 3.27.
Journal Article
•
DOI
•
Biofuels from microalgae—A review of technologies for production, processing, and extractions of biofuels and co-products
[...]
Liam Brennan
1
,
Philip Owende
2
,
Philip Owende
1
•
Institutions (2)
University College Dublin
1
,
Institute of Technology, Blanchardstown
2
01 Feb 2010
-
Renewable & Sustainable Energy Reviews