Post on 08-Jul-2015
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G R O U P :
LU I S A M A R O
I S T VA N LÓ P EZ
V I C TOR S E R R A NO
M A N U EL F O NTÁ N
Research Purpose:
Find alternative solutions or remedies for producing clean energy from poultry waste
Through data, we will evaluate if there is any possibility to use bio-gas as an economic fuel
Analyze its composition and properties
Describe and illustrate the process for producing bio-gas
Provide an example involving the Carnot Cycle (an ideal cycle with zero irreversibility)
Provide a study for public health
General analysis of producing energy through bio-gas
Benefits of using poultry waste as fuel:
Properly convert waste into eco-friendly energy which will improve economical issues
Improve general community well being
Prevents the propagation of diseases, mosquitoes, flies, and other pests
Low cost for machinery maintenance because of its simple process
During anaerobic digestion, organic nitrogen is converted into a more-valuable fertilizer, ammonium
Independent of rising fuel costs, it is a predictable and, almost, constant energy production and costs
Beneficial process because it improves various aspects of society
Bio-gas Composition:
Gas Properties Composition Porcentage Molecular Weight
Methane (CH4) 60% 16.04 lb/lbmol
Carbon Dioxide (CO2) 35% 44.01 lb/lbmol
Hydrogen Sulfide (H2S) 1.67% 34.08 lb/lbmol
Ammonia (NH3) 1.67% 17.03 lb/lbmol
Water Vapor (H20) 1.67& 18.02 lb/lbmol
Bio-gas is composed of various compounds (mostly methane gas)
What is methane gas?
Methane gas (CH4) is a chemical compound that is a principal component of natural gas due to
its simplest alkane
Most potent greenhouse gas with over 20 times the heat-retaining capacity as CO2.
Burns easily and produces a hot flame
Odorless, harmless, and tasteless
Good source to use as a fuel
A chemical compound highly useful for combustion
Precautions and Cons of process:
Requires expertise and skills for anaerobic digesters
Manure and digestive system must be compatible
Requires much waste for it to be feasible
Methane can be dangerous if mixed with air
Methane leaks are difficult to detect because it is odorless, colorless, and it’s not visible
Requires additional work and precautions
How methane gas is produced naturally?
Production of methane is a natural occurring process
What is a digester:
They are typically constructed from concrete or steel
Most digesters require 20-30 days for the bacteria to convert the organic wastes into acids and then methane gas
The bacteria in a digester are very sensitive, requiring a pH of 7 and a consistent temperature near 35o C
Some use a cogeneration in which heat is added to accelerate the process
Digester is the principal and one of the most important component of the process
Process for decomposition of the bio-gas
Problem Proposed:
Engineering Process:
Carnot Cycle
Engineering Process Continued: Defining the system
Dividing the Cycle into 4 processes
-Process 1-2
-Process 2-3
-Process 3-4
-Process 4-1
Applying Energy Balance Equation (First Law of Thermodynamics) to obtain heat transfer and work in each process
Total work for the cycle will be obtained by the summation of each work in each process
Process 1-2:P = 10 Bar
T = 179°C = 452K Process is Isobaric and Isothermal
m = 25kg of 𝐻2𝑂 It goes from saturated liquid to saturated vapor
ν 1=1.1273x10−3𝑚3
𝑘𝑔𝑢1=761.81
𝐾𝐽
𝑘𝑔ℎ1=762.81
𝐾𝐽
𝑘𝑔
ν 2=0.1944𝑚3
𝑘𝑔𝑢2=2,583
𝐾𝐽
𝑘𝑔ℎ2=2,778.1
𝐾𝐽
𝑘𝑔
𝑊1−2 = 12𝑑𝑣 = 𝑝 𝑣2 − 𝑣1 = 10𝑥105
𝑁
𝑚2 0.1932727𝑚
𝑘𝑔= 193.2727
𝐾𝐽
𝑘𝑔
𝑄1−2 = 𝑚 ℎ2 − ℎ1 = 50,382.25𝐾𝐽
Process 2-3:Steady State→ = 𝑄𝑐𝑣 − 𝑊𝑐𝑣 + 𝑚𝑖 ℎ𝑖 − 𝑚𝑒(ℎ𝑒) 𝑥3 = 90%
Adiabatic
𝑃3 = 1 Bar 𝑇𝑠𝑎𝑡 = 99.63°∁
𝑄𝑐𝑣 = 0
𝑊𝑐𝑣 = 𝑚 328.404𝐾𝐽
𝑘𝑔 𝑚 = 1
𝑘𝑔
𝑠
𝑊𝑐𝑣 = 328.404𝑘𝐽
𝑠
Process 3-4:𝑄3−4 =
𝑇𝑐
𝑇𝐻𝑄2−1 𝑄2−1=2,015.2900
𝐾𝐽
𝑘𝑔𝑇𝐻 = 453𝐾 𝑇𝐶 = 373𝐾 P=1Bar
𝑄3−4 =𝑇𝐶
𝑇𝐻−2,015.29
𝐾𝐽
𝑘𝑔)= −1,659.3889
𝐾𝐽
𝑘𝑔
ℎ4 = ℎ3 + 𝑄3−4
ℎ4 = 790.3071𝐾𝐽
𝑘𝑔
Process 4-1:Q = 0
𝑣4 = 0.2369𝑚3
𝑘𝑔𝑢4 = 708.3215
𝐾𝐽
𝑘𝑔
𝑣1 = 1.1273𝑥10−3𝑚3
𝑘𝑔𝑢1 = 761.68
𝐾𝐽
𝑘𝑔
𝑊4−1 = 𝑢4 − 𝑢1
𝑊4−1 = −53.36𝐾𝐽
𝑘𝑔
Efficiency:η =
𝑊𝑐𝑦𝑐𝑙𝑒
𝑄𝐻 𝑊𝑝𝑟𝑜𝑐𝑒𝑠𝑠 = 𝑊1−2 +𝑊2−3 +𝑊3−4 +𝑊4−1=339.5367
𝐾𝐽
𝑘𝑔
η =339.5367𝐾𝐽/𝑘𝑔
2,015.29𝐾𝐽/𝑘𝑔= 0.1684
η = 16.85%
η𝑚𝑎𝑥 = 1 −𝑇𝐶
𝑇𝐻= 0.1766
η𝑚𝑎𝑥 = 17.66%
The process is possible
Exergy Analysis:
𝑃0 = 1𝐵𝑎𝑟
𝑇0 = 7℃ = 280𝐾
𝑑𝐴𝑐𝑣
𝑑𝑡= 2.5104
𝐾𝐽
𝑘𝑔
Change in availability is positive
Public Health Impact:Methane is not toxic; however, it is extremely flammable and may form explosive mixtures with air
Breathing in methane at high concentrations, resulting in oxygen deficiency, are increased breathing and pulse rates, lack of muscular coordination, emotional upset, nausea and vomiting, loss of consciousness, respiratory collapse and death
Hydrogen sulfide is a highly toxic and flammable gas that cause eye irritation, a sore throat and cough, nausea, shortness of breath, and fluid in the lungs (pulmonary edema). Also, may result in fatigue, loss of appetite, headaches, irritability, poor memory, and dizziness, or immediate collapse, with a high probability of death
Ammonia is irritating and corrosive that may cause burning of the nose, throat and respiratory tract, if breathed. Also,
High concentration of carbon dioxide may result in nausea and vomiting, collapse, convulsions, coma and death can occur
Effects for improper handling of this process
Public Health Impact Continued:
Provides a renewable source of energy
Leads to improvement in the environment, and better sanitation and hygiene
Lower the greenhouse effects on the earth’s atmosphere
Produces enriched organic manure, which can supplement or even replace chemical fertilizers
Anaerobic digestion inactivates pathogens and parasites
Pros that makes the process feasible
Economical benefits: The digester produces a richer fertilizer with 3 times more nitrogen than a conventional product. Also it is natural and free from harmful synthetic chemicals
Biogas is fully capable of replacing other rural energy sources like wood, hard coal, kerosene, plant residues, and propane
Biogas can be used for cooking, lighting, space heating, water heating, grain drying, gas-fired refrigeration or air conditioning
The technology is cheaper and much simpler than those for other bio-fuels, and it is ideal for small scale application
Leads to employment generation in the rural areas
This method will sustain basic energy needs. Initial period will yield losses, but has potential to obtain long-term profit
Real Example:
Real Example Continued:
Annual-total investment of $23,911 and annual savings of $14,300, giving an annual loss of $9,600 in first year
Approximated Example:
· Fresh Manure @ 25% Solids = 1,620 gallons per day
· Dilution Water Required for 8% Solids = 3,440 gallons per day
· Total Waste Volume Generated = 5,060 gallons per day
· Digester Detention Time = 22.5 days
· Digester Tank Capacity = 22.5 x 5060 = 113,850 gallons
50,000 - BIRD LAYER OPERATION
Round tank: 27 ft (diameter) x 26.5 ft (tall)
References:
http://www.greencarcongress.com/2010/02/biogas-climate-benefit-greater-than-previously-thoughtlund-20100219.html
http://www.bae.ncsu.edu/programs/extension/publicat/wqwm/ebae071_80.html
http://hyperphysics.phyastr.gsu.edu/hbase/thermo/carnot.html
Questions?