Helo
Because pig waste has 80 porcent water , biogasification will
be the correct choice followed by termal cracking/gasification .Thus
the energy input can be minized as rapid bioconversion is also the
comercial process.
Energy balance can make the etanol process less competitive related
with natural gas compression , which is simple , can be built easily
with suatianble coproducts. The the effluents is rich 2 time in
protein as animal feed can be much more sustainable to prevent
polution
sd
Panniselvam P V
On 7/9/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> Robert mentioned his concern over the masses of animal waste
> pouring into the rivers. I found these articles showing how in N
> Carolina they are starting to make pig waste into ethanol. Has
> anyone researched this area?
> Marilyn
>
>
> http://mark.asci.ncsu.edu/SwineReports/2001/03manbrett.htm
>
> Formation of Fuel-Grade Ethanol
> from Swine Waste via Gasification
>
> B. Kaspers, J. Koger, R. Gould[1], A. Wossink[2], R. Edens[2],
> and T. van Kempen
>
> Summary
> The objective of this project is to investigate the application of
> gasification technologies to the treatment of swine waste for the
> ultimate production of fuel-grade ethanol. This waste treatment
> system would reduce the negative environmental impact of
> current manure management systems. The research objectives
> are: 1) to develop and test a system for harvesting swine manure
> in a form dry enough to be used as a gasification feedstock, 2) to
> establish the feasibility and the gasification conditions for the
> swine waste/amendments feedstock, 3) to characterize the end
> products of gasification (ethanol and mineral ash) and their
> potential markets, and 4) to conduct a rigorous economic
> analysis on the entire swine manure management model to
> determine its feasibility along with the factors that promote or
> impede its implementation.
>
> Introduction
> Ethanol production (primarily via fermentative methods) from
> crops and other "renewable" biomass sources has received
> much attention recently, but the current approach has problems.
> Mainly, crop-based feedstocks are subject to seasonal
> fluctuations in supply, ultimately limiting ethanol generation.
> Such feedstocks necessitate either lengthy storage of the
> perishable plant materials or stopping ethanol production
> altogether during the off-season. Another dilemma faced is that
> some of the feedstocks currently used in ethanol production (e.g.
> corn stubble) have a greater value elsewhere (e.g. fertilizer).
> More specifically, the energy cost in harvesting these feedstocks
> (e.g. corn stubble) as well as their lost value as soil
> amendments makes ethanol production costly to farmers
> (Pimental, 1992). Animal manures avoid many of these
> problems because they are a truly renewable feedstock.
>
> The quantity of swine manure produced in the U.S, estimated at
> 5 billion kg dry matter per year, is sufficient to contribute
> substantially to ethanol supplies. Assuming a conversion
> efficiency of 40%, there is a theoretical ethanol yield of 500
> million gallons per year. North Carolina is the second largest
> hog-producing state within the U.S. with a swine population
> large enough for gasification technology to be feasible. Thus,
> ethanol production of 80 million gallons per year should
> theoretically be attainable. The most recent RFA (Renewable
> Fuels Association) Ethanol Report (May 11, 2000) concludes that
> replacing corn with less expensive feedstocks will result in
> substantial reductions in ethanol production costs.
>
> Gasification of biomass has received much attention as a
> means to convert waste materials to a variety of energy forms
> (i.e. electricity, combustible gases, synfuels, various fuel
> alcohols, etc.). Gasification is a two-step, endothermic process
> in which solid fuel is thermochemically converted into a low or
> medium Btu gas. Pyrolysis (Step 1) of the biomass is followed
> by either direct or indirect oxygen-deprived combustion (Step 2)
> during the gasification process. This process converts raw
> biomass into a combustible gas, retaining 60-70 % of the
> feedstock's original energy content. Thermochem's steam
> reformer is the system we are investigating to gasify our
> feedstock because this type of gasifier produces a
> hydrogen-rich, medium-Btu fuel gas. This gasifier design
> percolates superheated steam through an indirectly heated inert
> fluidized bed of sand or a mineral material. The organic
> feedstock injected into the bed undergoes a rapid sequence of
> pyrolysis and vaporization reactions. Higher hydrocarbons
> released among the pyrolysis products are steam cracked and
> partially reformed to produce low molecular weight species.
> This process produces a gas with nearly immeasurable
> environmental emissions of NOx, SOx, CO, and particulates. The
> main reason this particular gasifier design is favored is because
> of its hydrogen to carbon ratio (2:1) is ideal for ethanol synthesis.
> A recent cost and performance analysis of biomass (i.e. wood)
> gasification systems for combined power generation indicated
> that such a steam system (Battelle Columbus Laboratory) had
> the lowest capital cost and product electricity cost (Craig and
> Mann, 1997).
>
> There is an intensive effort, especially in North Carolina, to
> develop a better waste management strategy. The ultimate goal
> of this project is to eliminate the land application of lagoon
> effluent. The elimination of this waste via gasification would
> abolish the need for land application of waste.
>
> The primary obstacle to overcome in this project is converting the
> swine manure into a suitable feedstock for gasification. Factors
> such as moisture content, density, and transportation
> requirements must be investigated. The most common waste
> systems currently employed, the lagoon (1% Dry Matter (DM))
> and slurry basin (10% DM), do not produce a waste stream
> which makes for a suitable feedstock for gasification and thus
> alternative waste management systems must be developed.
> When the appropriate feedstocks are selected, the gasifier will
> be engineered to maximize product gas yields.
>
> Results and Discussion
> Initially, fresh fecal samples were collected from our swine
> research facility (Jan. 2000) to corroborate literature findings that
> claim swine feces is typically 20-30% dry matter. The mean DM
> for the fresh fecal samples obtained from grower/finisher pigs
> fell within the reported range at 28.6%. These DM values were
> not significantly (p= .26) different between the various sized
> (50-200 lbs.) grower-finisher pigs. The mean energy value of the
> samples was found to be 4361 cal/g. However, the energy
> values displayed a decreasing trend as body size increased (p=
> 16). This trend can be explained by the increase in digestion
> time that occurs with an increase in the animal's body weight. In
> comparison to other potential feedstocks for gasification (Table
> 1), swine waste has a high enough energy value to make
> gasification feasible.
>
> Table 1. Energy content ranking (highest to lowest) among
> possible feedstocks
>
> Material Energy content (cal/g)
> Corn cob 4928
> Birch wood 4613
> Swine waste 4361
> Corn straw 4253
> Wheat straw 4247
> Rice straw 3903
>
> A thorough investigation of existing swine waste management
> systems within the U.S. suggests a low probability for obtaining
> feces with a desired DM content for steam reformation (60-80%)
> from currently employed systems (most commonly the lagoon
> and the slurry basin). Some alternative housing systems like
> hoop structures (found primarily in the Midwest) and dry waste
> systems (Hog high-rise in Ohio) have been examined. Samples
> were obtained from three hoop facilities in Indiana because they
> utilize a deep bedding system which could yield a dry waste.
> Analysis of these samples determined that this waste stream
> was unsuitable as a possible feedstock for steam reformation
> with a mean dry matter content of only 41%. Analysis of samples
> for DM and energy content from the high-rise in Ohio will be
> conducted in the future.
>
> European swine research facilities have shown that a conveyor
> belt collection system seems favorable for obtaining a drier
> waste stream. Thus, we designed a small-scale (single pen)
> belt unit with plans to construct a large-scale (100 pigs) model in
> the summer of 2000. These units should provide us with a
> suitable feedstock for steam reformation without having to
> employ additional drying mechanisms.
>
> Initially, we set up a housing structure to simulate a belt system,
> in order to measure ammonia emissions. The system
> consisted of grower/finisher pigs housed within a pen on
> tenderfoot flooring with PVC sheets slanted six inches below it,
> allowing the urine to drain away from the manure. This structure
> was housed within one of our enclosed chambers where
> ammonia levels were monitored using an FTIR (Fourier
> Transform-Infrared) spectrophotometer. There was no increase
> in ammonia emission over the three days the animals were
> housed there, in contrast to the usually observed increase in
> ammonia emissions. This finding suggests that an innovative
> manure collection system like the conveyor belt will dry the
> manure as well as reduce odors within the swine housing
> facility, making it a more environmentally friendly system.
>
> Next, we built a small-scale model, consisting of one pen with
> tenderfoot flooring and a plastic belt running below it. Our first
> pilot trial was with grower/finisher pigs averaging 31 kg.
> Although this system required improvements, a DM of 60% was
> achieved, indicating the system could produce a feedstock for
> gasification. This trial also examined DM as a reflection of times
> between collections off the belt. Dry matter seemed to be the
> highest when the belt was moved one foot each day over a
> three-day period. Further investigation into the collection periods
> will be examined in subsequent pilot trials after which a larger
> scale unit will be built.
>
> Implications
> Our research thus far has shown that swine manure can be a
> suitable feedstock for gasification. The belt system (an
> alternative waste management system) has the potential to dry
> the swine waste to more than 60% DM. Investigation into
> possible amendments of North Carolina's cash crop wastes (i.e.
> peanut shells, wood shavings, wheat straw, etc.) remains a
> possibility for producing an even drier feedstock. Alterations to
> the steam reformer will be performed to optimize product gas
> composition for ethanol production and to allow for flexibility in
> feedstocks (with or without amendments, varying dry matter
> contents, etc.). Also, the ash product produced in the steam
> reformer will be examined for use as a mineral source in animal
> feeds or as a fertilizer. The final conclusion regarding the
> feasability of gasifying swine waste will be dependent upon the
> economic analysis of the entire housing and gasification
> system. A decision support system (DSS) will be developed that
> stimulates and optimizes the whole chain from animal
> production to manure spreading or processing. The system will
> assess the logistics, economics, and environmental effects for
> each of the elements of the chain. An economic/environmental
> sensitivity analysis of gasification as a manure processing
> technology will be performed by changing the options (such as
> subsidies on ethanol), constraints (particularly the regulatory
> context), and model assumptions step by step. The results will
> be compared to an environmentally sustainable system based
> on current technologies, waste disposal by land application at
> agronomic rates that avoid eutrophic consequences.
>
> Literature Cited
> Craig, K.R. and Mann, M.K. "Cost and Performance Analysis of
> Three Integrated Biomass Gasification Combined Cycle Power
> Systems". DOE BioPower Program Technical Reports, Aug.
> 1997.
> Pimental, D. 1992. Energy inputs in production agriculture.
> Energy in World Agriculture. ed. R.C. Fluck. Amsterdam; Elsevier.
> Pgs. 13-29.
> ------------------------------------------------------------------------
> [1] Mechanical & Aerospace Engineering
>
> [2] Agricultural and Resource Economics
>
> Research & Grad. Studies
> NC State University
> 103 Holladay Hall
> Campus Box 7003
> Raleigh, NC 27695
> (919) 515-2117 - Phone
> (919) 515-7521 - Fax
>
>
> http://www.ces.ncsu.edu/depts/agcomm/writing/2001/012201b.h
> tm
>
> Jan. 22, 2001
>
> Researchers explore turning pig manure into ethanol
>
> A team of North Carolina State University researchers is studying
> the feasibility of turning pig manure into ethanol, which may be
> used as fuel for automobiles. If the strategy the researchers
> have mapped out proves feasible, they believe it will address
> many of the waste management headaches the North Carolina
> swine industry now faces and perhaps produce a new industry
> for rural parts of the state.
>
> At the heart of the plan is a process called gasification, said Dr.
> Jeanne Koger, project director. Other members of the team are
> Dr. Theo van Kempen, a swine nutritionist, and Dr. Ada Wossink,
> an economist. The three are with N.C. State's College of
> Agriculture and Life Sciences.
>
> Gasification, Koger explained, is the process of burning a
> substance in a low-oxygen environment to convert complex
> organic compounds to gases. Koger and van Kempen plan to
> gasify pig manure, releasing gases such as methane, carbon
> monoxide and hydrogen. The gases will be collected and used
> to make fuel-grade ethanol.
>
> Koger said there is a ready market for ethanol in state-owned
> vehicles that have been converted to run on ethanol, which burns
> more cleanly than gasoline. Indeed, some of the funding for the
> project is coming from the state Energy Office, which is looking
> for ethanol sources.
>
> But the project encompasses considerably more than gasifying
> manure. Before manure can be gasified, it must be relatively dry,
> Koger said. That's a problem in North Carolina, where swine
> waste is usually diluted with water in lagoons. Koger said
> manure must be 60 to 80 percent dry matter before it can be
> gasified successfully. The manure in a lagoon is typically about
> 1 percent dry matter, while fresh feces are about 30 percent dry
> matter.
>
> The barns in which pigs are raised usually have slotted concrete
> floors. Swine waste drops through the slots to a pit below. From
> there, the waste is flushed into a lagoon. The researchers
> propose using a belt system to collect and dry manure. The belt,
> located under the slotted floor, acts as a conveyer, moving
> manure to the end of the barn, where it can be collected.
>
> Koger said it should be possible to retrofit swine barns with
> plastic belts. The belts will be positioned at an angle so that
> urine runs off while solid waste remains on the belt. When solid
> waste is separated on the belt, it dries fairly quickly, Koger said.
> The researchers have already experimented with a pilot system
> that treated waste from 15 pigs. Using the pilot system, they
> were able to produce manure that was 55 to 75 percent dry
> matter.
>
> Belt manure collection systems are already in use in Europe,
> van Kempen said, and some of the support for the project is
> coming from a company that makes belt systems.
>
> Koger said using a belt system should address two major
> headaches for hog farmers: odor and ammonia emissions. She
> explained that both odor and ammonia are produced by the
> action of fecal microbes on the manure constituents. If urine and
> solid waste are separated, and the feces dried, odor and
> ammonia emissions should be reduced dramatically.
>
> Based on previous research, ammonia reductions of at least 80
> percent are expected from a belt system. The belt system
> addresses these problems in the barn, where they first occur,
> unlike other waste management technologies that deal with
> waste after it leaves the barn.
>
> Ammonia is a problem because it can volatilize and move into
> the atmosphere. It may later come back to earth dissolved in
> rainwater. Ammonia is a form of nitrogen, which is a nutrient.
> Excess nitrogen in waterways can fuel algae blooms. The algae
> then die, and decomposition of the plants depletes the water of
> oxygen. That can lead to fish kills.
>
> The researchers have already satisfied themselves that pig
> manure can be gasified. They sent manure samples to
> ThermoChem, a Baltimore company, which successfully
> gasified the samples.
>
> Koger, van Kempen and Wossink see a number of advantages
> to the waste treatment system they envision. They describe the
> system as "holistic," explaining that it uses all the wastes from a
> swine operation without negatively affecting the environment.
>
> The system should provide substantial odor and ammonia
> emission control. It will not be seasonal in nature, as is the
> lagoon-and-spray-field system now used by most North Carolina
> farmers. Lagoon liquid is sprayed on fields as a fertilizer, but the
> plants that use the nutrients in the waste grow more actively and
> take up more nutrients during the growing season. Ethanol can
> be manufactured and used year round.
>
> Because manure would be dried and taken to a gasification
> facility, the system requires relatively little land for waste storage
> or treatment. And the system would not require an open waste
> storage or treatment facility, like a lagoon.
>
> Koger said the system should be particularly suitable for areas
> like Sampson and Duplin counties, with large swine populations
> in a relatively small area. Were gasification facilities to be
> located in these counties, there should be no shortage of
> manure (each county has around 2 million pigs). At the same
> time, the distance from any given farm to a facility would be
> minimal, so the cost of moving manure should be reasonable. At
> the same time, gasification facilities would represent a new
> industry for the area.
>
> The researchers see one other potential benefit from the
> system. In addition to producing gases, gasification also makes
> ash. The ash contains the minerals that were in the manure, van
> Kempen said. The ash should have value as either a fertilizer or
> an animal-feed supplement. The ash might end up going back
> to the hog farms from which it came, where it would become part
> of the pigs' diet. The ash would be completely safe to use as a
> feed supplement, van Kempen pointed out, because any
> pathogens in the manure would be destroyed by the extreme
> temperatures (in excess of 1,100 degrees F) used to gasify the
> manure.
>
> The researchers plan over a two-year period to determine the
> feasibility of retrofitting barns with belts, then collecting, drying
> and gasifying manure. The next step, which is being funded by
> the Animal and Poultry Waste Management Center at N.C. State,
> is to build and test a prototype belt collection system.
>
> Koger said that they anticipate the system will manage waste
> from approximately 120 pigs. The prototype will be located either
> on N.C. State's campus or at the university's Lake Wheeler Road
> Field Laboratory, just south of Raleigh. Using data from the
> prototype, Wossink will determine if the strategy is economically
> feasible.
>
> --D. Caldwell
>
>
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--
Pagandai V Pannirselvam
Universidade Federal do Rio Grande do Norte - UFRN
Departamento de Engenharia Química - DEQ
Centro de Tecnologia - CT
Programa de Pós Graduação em Engenharia Química - PPGEQ
Grupo de Pesquisa em Engenharia de Custos - GPEC
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