User:Shravan: Difference between revisions

Shravan Kumar Bittla

I am a Master Student of Electrical Engineering with specialization in Power engineering at Michigan Technological University and my key interests areas are renewable energy systems, sustainable development.

Interests

Renewable Energy and Resources that provide clean energy.Interested in learning effective methods of energy generation and maximizing efficiency.

Literature Review

Exergy and CO2 Analyses as key tools for the evaluation of Bio-Ethanol Production=

Exergy and CO2 Analyses as key tools for the evaluation of Bio-Ethanol Production^[1]

Energy a thermo dynamic analysis technique.

Exergy is defined as “exergy is the maximum work that can be produced when a heat or material stream is brought to equilibrium in relation to ref environment” ( Dewulf.J,2010) The analysis identifies the energy and exergy loses in a system which is usually used in a poly-generation System and as for mainly thermochemical pathways The biofuel generation is considered as more successful in an integrated plant of first and second generation. The thermodynamic efficiency of a system is

                  efficiency =(Exergy  of useful products )/(Input Energy)

For Lignocellulosic

                  efficiency = (Exet+Pnet+Ex res)/(Exbm+ ?Exch.+ExLT)

The corn based plants positive energy results are doubtful exergy results.

Effects of acid treatment on different parts of corn stalk for second generation of ethanol production

Effects of acid treatment on different parts of corn stalk for second generation of ethanol production^[2]
The effect of acid treatment has different effects on different parts of corn stalk for second generation ethanol production. Sulfuric acid is mostly used to depolymerize the lignin and hemicellulose fractions. pretreatment - 2% (w/v),H2SO4,121°C under 10%(w/v) solid loading for 60 min Solid fractions then collected at 105°C overnight, and stored at 4°C. Enzymatic hydrolysis/fermentation -50°C,150rpm in 0.01M citrate buffer (pH 4.7) Cellulase 15FPU/g of solid Fermentation was performed 30°C/200rpm in 1L bio reactor with working volume of 600ml,pH at 6 by ammonia,Sterilization of hydrolysis was done at 121°C . Recovery rate of Solid = Wpre/Wraw*100 Glucose Yield % = (amount of glucose in enxyme hydrolysate*0.9)/(amount of cellulose in pre treatment sample*100%) The Glucose content in husk was found high, lignin content was low ,xylan content was high in cob. Pro pre-treatment enhanced the overall efficiency in ethanol production. Ethanol Energy Return on Investment A survey of the literature 1990-present (http://pubs.acs.org/doi/abs/10.1021/es052024h) Roel Hammerschlag” Ethanol Energy Return on Investment A survey of the literature 1990-present” The paper discusses the net energy return on ethanol production- a review of different studies has been taken into account. The studies considered two methods, ethanol from corn starch and cellulosic ethanol. The term RE has been considered to represent the net energy of ethanol to the non –renewable energy input in manufacturing process. Studies by pizmental & patzak implied that the net renewable energy return is zero for the invested fossil fuels .

Pretreatment technologies for efficient bioethanol production process based on enzymatic hydrolysis

Pretreatment technologies for efficient bioethanol production process based on enzymatic hydrolysis^[3]

The paper concerns the issues regarding the technologies employed in biofuel produce from   
lignocellulosic materials. The process has a lot of chemical barriers as it should lead to high yields, digestible. The amount of toxin compounds should be kept low .The energy consumption can be kept low if the dry content is high in raw material.to ensure adequate ethanol produce concentration of sugar from coupled operation should be kept above 10%.heat requirements should be kept low.

Among all the pre-treatment methods considered chemical and thermochemical found to be the best technologies available.

Biomass Electricity generation at ethanol plants –achieving maximum impact.

Biomass Electricity generation at ethanol plants –achieving maximum impact ^[4]
The paper studies the energy and electrical needs of 50 million gallon/year ethanol plant. The system performance of superheated steam drying and conventional steam tube drying are done for syrup and corn stover, corn stover fuels. It was found that superheated steam drying had more efficiency in electrical generation and low thermal efficiency. The process heat required was also less than the steam tube dryer. System performance was same for both syrup and corn stover, corn-stover.as syrup-corn stover had a small increase in the power sent back to grid. There’s reduction in GHG gases due to increase in electricity production. The corn entering into a plant is usually converted into one-third of distilled grains, one-third of CO2.Two driers are used for syrup and corn stover. The net energy required to remove water in superheated system drier is about 1000 KJ/kg(430 btu/lb) compared to about 2070KJ/kg (1150 BTU/lb) The water condensed is reused in ethanol processing thus reducing net water intake in ethanol processing. The logistics and storage of bio raw material has been studied.

Net energy balance of ethanol production

Net energy balance of ethanol production^[5]

The paper review about the net energy balance of ethanol produce.

The net value of energy is considered positive as the net intake of energy and non-renewable resources has decreased over years Average yield of 2.76 gallons of ethanol/bushel of corn was reported .with approx. 2.74% -wetmill,2.81% -dry mill. BTU per gallon of ethanol produced is around 20545. The large portion of energy consumed is in drying co-product distillers grain. 42 gallons of water per gallon of ethanol is consumed. The corn produced in US is mostly not irrigated co-products from plants are distiller grains for livestock feed and CO2 in food and beverage industry. The paper makes a strong point on considering the net energy credits to by-products obtained

Ethanol can contribute to energy and environmental goals.=

Ethanol can contribute to energy and environmental goals ^[6]

The study reviews 6 paper related to the study of ethanol energy balance. It focuses mainly on the calculation of net energy produce of ethanol as it confirms that most studies ignore the byproducts in ethanol production.one ml of gasoline needs more petroleum than one ml of ethanol. The cellulosic ethanol is being considered far more advanced technology.

Energy and Resource group Biofuel analysis meta model has been used to compare data across different studies. The study reported that ethanol and co-products yielded a positive net energy 4MJ/L to 9 MJ/L

Ethanol Industry and process descriptions

Ethanol Industry and process descriptions^[7]
The process involved in ethanol produce has been studied Integrated bio refineries are envisioned as key model for future, Bio refineries which use fuels, chemicals animal fuels as they increase profitability. Corn is the most used ethanol product in USA The main process of ethanol production . Corn dry milling- cleaning, milling, liquefaction, addition of alpha amylase to break down starch. Saccharification, Distillation, Dehydration, Distillation, dehydration, rectifying columns, molecular sieve. Co-products – silage of distillation columns, centrifuge-solids Wet milling- Similar process but corn kernel is separated into its components Cleaning, steeping, germ fiber starch separation, saccharification, Fermentation, Distillation,dehydration Co-product processing-corn gluten meal, corn gluten feed

Biomass-to-bioenergy and biofuel supply chain optimization: overview, key issues and challenges

Biomass-to-bioenergy and biofuel supply chain optimization: overview, key issues and challenges^[8]
The paper focuses on optimization and planning of biomass and biofuel generation. The planning strategy from Bio feed stock supply to biomass energy storage and the technicalities of different biofuel procedures have been considered. Biomass pathways-terrestrial, aquatic biomass feedstocks Cellulosic ethanol is being considered due to the adverse effect on food crops Biodiesel, Intermediates corn, pretreatment, hydrolysis, Lipids, syngas, Bio oil, Feed stock supply needs to be regular. Thermochemical technologies-gasification, pyrolysis, algae harvesting and conversion. Distribution over long distance is very difficult. It reviews that cellulosic procedure is best.

Life cycle analysis of solar PV system

Life cycle analysis of solar PV system ^[9]
The paper reviews the life cycle analysis of different PV systems modules. The entire lifecycle of PV cell from the point manufacturing and installing of PV cells and GHG are considered It reports that crystalline modules had good conversion efficiency but high energy inputs and GHG emissions.Thin film modules have less energy inputs and GHG emissions.

Exergy Based Energy efficiency and renewability Assessment of Bio Fuel Production

Exergy Based Energy efficiency and renewability Assessment of Bio Fuel Production^[10]
The article provides comparative exergy based efficiency analysis of three crops mainly corn,soy bean, Rapeseeds in the produce of bio fuel. Exergy Based analysis to assess the net Renewable energy from non-renewable resources Highest amount of exergy 220 GJ ha-1 yr-1 is obtained from corn produce. Solar energy is the major input for all the three crops rather than the seeding material The net efficiency of solar energy input is negligible. Corn proves to be the best on the overall process and major part of energy produce has a low non renewable energy part.

Resource use efficiency and environmental performance of nine major biofuel crops,processed by first generation conversion techniques.

Resource use efficiency and environmental performance of nine major biofuel crops,processed by first generation conversion techniques ^[11]
In this article nine main crops like maize, wheat, sugar beet, cassava, sweet sorghum, sugarcane, winter oil seed rape, soy bean, oil palm have been considered. GHG emissions have not been considered as CO2 has already been absorbed from atmosphere Net energy yield has been calculated taking into account non-renewable inputs. Land use and soil erosion have been considered basis on the crop conditions, it was found that cassava and sugarcane have most soil erosion . It was found that crop with favorable energy ratios don’t necessarily produce Net yield per unit of water has been considered, but water usage in industrial conversion stage has not been considered. A crop with more usage of pesticide has been considered less sustainable. The study states that corn has the highest energy conversion efficiency. Sweet sorghum, sugar cane and palm oil seed found to deliver more energy than the energy input.

Variation in corn stover composition and energy content with crop maturity

Variation in corn stover composition and energy content with crop maturity^[12]
In this article corn stover over crop maturity has been considered. Total Exp was conducted for 213 days by harvesting corn (32K61,32K64) and they found that the crop which is harvested at a maturity state has given 54% of stover and 64% of grain The crops which have harvested a 213 days lost 74% of dry matter which is due to respiration of microbes. The end of experiment it was found that the amount of dry matter in stover found to be 11.7 ton ha-1 ,the dry matter and the green is same as 11.7 ton ha-1 The gross energy of corn stover is 17.65 KJ gm-1 by calerometric analysis. It can be clearly stated that the stover with dry content has given better result.

Life cycle assessment of various cropping systems utilized for producing biofuels :Bioethanol and biodiesel

Life cycle assessment of various cropping systems utilized for producing biofuels :Bioethanol and biodiesel ^[13]
In this article life cycle assessment of crops in ethanol and biodiesel production has been considered. Corn stover which is complete upper part of crop except grain uses more energy in harvesting, and has increased ethanol production ha-1 41-65% than continuous corn grain. Cropping system scenarios of Continuous corn, corn with soy bean. Corn grain is processed into ethanol via corn wet milling with a ethanol yield of 0.3 kg ethanol per kg of dry corn grains. Corn-soy bean rotation crop had less renewable energy resources and has lowest ethanol production. The CC ,CS cropping system has negative green house gas emissions. Corn stover as raw material for ethanol saw a increase of ethanol production of 41-65% per hectare.

Engineering aspects of collecting corn stover for bioenergy. Engineering aspects of collecting corn stover for bioenergy. ^[14]
In this article Corn Stover isconsidered including the moisture content .where it is considered in 1:1 ratio for dry matter of corn grain to dry matter of dry stover . Yield of stover is calculated from the corn grain produce with an increase in mass of above ground crop The moisture content of stalks and leaves has found to be 82% and grain was about 34 % Monitoring of moisture content has been consider A field test was conducted with corn grain yield of 8.8 t ha-1 as we considered 1:1ratio stover is 8.8 t ha-1. Losses due to delayed harvesting has been observed. It is observed that timely harvest and stover handling has to be done accordingly.

Techno-Economic comparision of process technologies for biochemical ethanol production from corn stover

Techno-Economic comparision of process technologies for biochemical ethanol production from corn stover^[15]
The study has been conducted by comparing different process technologies of ethanol from lignocellulosic material. Different treatment technologies of biochemical analogies have been considered for biochemical ethanol production. Ethanol yield per mass of feed stock is lower in 2-stage dilute acid treatment and high in C5 and C6 fermentation. The advantage of cellulosic ethanol is the internal energy is supplied by the plants by-products Ethanol product value increase when feedstock value is increased. The product value can be considered based on enzyme cost . It was observed that the ethanol yield by 2-stage dilute acid being the lowest (76gal/mg)

World Agricultural Supply and Demand Estimates

[1]

This is a good source of data to study the latest trends in Agriculture.