الطاقة الجديدة والمتجددة الفرقة الثانية القوى الميكانيكية والطاقة

Dear all you are invited to our intarnational workshop in December 2017
details will be published later

يا جماعة دي صفحة للمقرر اللي بدرسه لسنه تانية ميكانيكا وان شاء الله نعمله مقرر اون لاين فعايزمقترحاتكم للتحسين لو سمحتم

شباب ثانية طاقة موعدنا الساعة 8-15 في قاعة 203 ان شاء الله

بعض ظواهر التحويلات المباشرة للطاقة

Biomass Energy
What is an Anaerobic Digestion Process?
It is a process of converting the biodegradable biomass material into energy (in the form of methane gas and a stable humus material) in the absence of oxygen by microorganisms. Such process needs special conditions and special design of vessels or landfills.
List the organic wastes and Biomass used as feedstock?
Municipal Solid Waste (MSW)
Agricultural Animal Waste
Corp residues, biomass, and energy corps
Wastewater treatment plant sludge
What is Inoculation?
Sometimes the biological process needs activation by adding livestock waste such process is known as “Inoculation”
How Biodegradability is estimated? Write a short not about each method.
Long-Term batch digestion studies: This method is based on a linear regression plot of the remaining volatile solids concentration as the retention time approaches infinity.
Measurement of Lignin Content (LC): an analytical method commonly used for determining the biodegradable volatile solid fraction of an organic substrate is based on the measurement of the crude lignin content of the volatile solids. Biodegradable fraction=0.83–0.028*LC (empirical relationship)
Chemostat studies: in which the biodegradable volatile solid fraction of an organic substrate can be estimated using chemostat techniques.
The True Digestible Organic Matter (TDOM) technique: is used to assess in animal feeds digestibility by adding to it the rumen fluid in vitro for 48 hrs.
The Biochemical Methane Potential (BMP) assay: Monitoring the cumulative methane production from a slurry sample which is incubated anaerobically for 30 days at 35℃ in a chemically defined media and inocula, (BMP = 100+ (3-10%) TDOM).
What are the Typical Reactor Types used for Anaerobic Digestion? Describe briefly with the aid of sketch.
a) Batch rector: It is fed once, and then the biotransformation is allowed to proceed until completion before any material is added or removed (needs more labour, more storage facilities and is inconvenient for large scale facilities)
b) Complete-mix continuous flow reactor: A reactor to which a waste stream is fed and a treated effluent stream is withdrawn continuously, municipal wastewater sludge treatment, fluctuation in feeding, sometimes needs storage, discharge of untreated or partially untreated wastes can occur which force recycling
c) Anaerobic contact reactor: It is as the Complete-mix continuous flow reactor but without recycling. The biomass is separated from the effluent and fed back to the reactor, suitable for meat and heavy waste treatment
d) Plug-flow reactor: It is a continuously or semi-continuously fed reactor where the fed materials (ideally) do not interact with the material fed after or before it. These reactors can be thought as tube through which batches of reacting materials are fed independently. It is of two types; Vertical plug-flow and Horizontal plug-flow reactors.
e)Attached growth reactor: It is used to prevent the bacterial population depletion by introducing some material on which Bactria can grow, materials such wood chips, stone granules, plastic materials with different shapes. This action increases the reactor efficiency. Figure 2 shows sketches of all these systems

Figure 3 Typical reactor types used for anaerobic digestion: (a) batch reactor, (b) complete-mix continuous flow tractor, (c) anaerobic contact reactor, (d) vertical plug-flow reactor, (e) horizontal plug-flow reactor, and (f) attached growth reactor.
Draw a flow diagram of bioenergy recovery system.

Figure 4 General flow diagram of bioenergy recovery system
What are the modes of operation of a bioenergy recovery system?
Modes of Operation for Anaerobic Digestion
1. Low-Solids Digestion: the digestion process needs solid to be less than 10%
2. High-Solids Digestion: the digestion takes place even the solid is 70% of the total substrate
3. Thermophilic Digestion: the bacteria needs high temperature to work effectively
4. Mesophilic Digestion: the atmospheric temperature is the best condition for bacteria to work
5.Two stage Digestion: sometimes the digestion need two different types of bacteria one is mesophilic and the other is thermophilic so it is required to separate them in two stages, also some bacteria digest wastes to organic acids and in the second stage the methane bacteria converts organic acids to methane. Each group of these bacteria needs different operating conditions so it is required to separate them from each other.
With the aid of sketch describe the steps of combustion of biomass
Combustion is the rapid oxidation of fuel to obtain energy in the form of heat-biomass fuels-. The combustion of biomass solid fuel passes through four processes (Figure 4):
Heating and drying: water removing step.
Pyrolysis: complicated series of thermally driven chemical reactions that decompose the organic matter in the fuel.
Flaming combustion: all volatile matter is released during pyrolysis, leaving the solid matter of the biomass (called Char) for the next process.
Char combustion: the oxidation is controlled by the mass transfer of oxygen to the char not by the chemical kinetics.

Figure 5 Processes of solid fuel combustion
With the aid of sketch describe the steps of thermal gasification of biomass
Gasification is the high temperature (750℃-850℃) conversion of solid, carbonaceous fuels into flammable gas mixtures – known as producer gas – consisting of CO,H_2,〖CH〗_4,N_2,〖CO〗_2 and smaller quantities of higher hydrocarbons. The overall process is endothermic and requires burning some of the fuel to produces heat for the reaction or an external heat source to drive the process. (Figure 5)
Heating and drying: water removing step.
Pyrolysis: complicated series of thermally driven chemical reactions that decompose the organic matter in the fuel.
Flaming combustion: all volatile matter is released during pyrolysis, leaving the solid matter of the biomass (called Char) for the next process.
Char combustion: the oxidation is controlled by the mass transfer of oxygen to the char not by the chemical kinetics.


Figure 6 Processes of solid thermal gasification
What are biofuels?
Bio-based transportation fuels, also known as biofuels, are currently dominated by ethanol and biodiesel. Ethanol, by virtue of its high octane number, is suitable for use in spark-ignition engines, while the high octane numbers of biodiesel, which are methyl or ethyl esters formulated from vegetable or animal fats, make them suitable for use in compression-ignition engines. However, there are other candidate liquid biofuels including methanol, mixed alcohols, and Fischer–Tropsch (F–T) liquids, as well as gaseous biofuels including hydrogen, methane, ammonia, and dimethyl ether.

Geothermal Energy
What are geothermal resources and how geothermal energy reaches the earth surface?
Geothermal resources are the thermal energy that could be reasonable extracted from ground at comparative cost compare with other forms of energy at some specific future time, the geothermal energy reaches the Earth surface through two different ways:
The radioactive decay of Uranium, Thorium, and Potassium in the Earth’s Mantle and Core produces heat flow outwards to the surface, and its value is not suitable for any application.
Localized heat resulting from the movement of the magma within the Earth’s crust.
What are geothermal regions?
Hydrothermal regions: where the temperature gradient is ≥80℃/m, and it is suitable for the production of electricity. It is found in the tectonics area.
Semithermal regions: where the temperature gradient is ~40−80℃/m and it is found far from the tectonics boundaries.
Normal regions: where the temperature gradient is

محاضرة تكنولوجيا تخرين الطاقة, تحياتي د.محمد رضا

this album contains the powerpoint presentation slides for the geothermal energy topic