Sin embargo, para que estas plantas funcionen es requisito indispensable que las empresas-clientes cuenten con la cantidad y calidad de residuos industriales necesarios para la generacin de energa que exige la tecnologa de plasma.How much does it cost to build a facility and who pays for it?Cost is determined by several factors: Size of plantLocationregulatory/permitting environmentdesired end-product (transportation fuels, electricity, or steam being the primary) in particular.

The proposed Sacramento plant is currently project at approximately $200M at no expense to local, state, federal, or tax-paying citizens, as it is a private development project. The final cost will be dependent on the results from the regulatory and permitting processes already established by the State of California and the resulting compliant plant design.

Naturally, the larger the plant, the higher the cost, but the greater the advantage of economy of scale to improve the overall financial return and the environmental benefits associated with the treatment of waste.http://www.usstcorp.com/faq.html

6. Economic evaluation of the thermal plasma gasification plant The major disadvantage of thermal plasma gasification processes mentioned by many scientists and engineers is the use of electricity, which is an expensive energy source

Although the prices of each country are different and data are not enough fully,the trend of construction cost according to capacity could be identified. 0.39 millionUS$/TPD applies to the 10 TPD plant constructed by GS Platech in Korea. For capacitiesbetween 250 and 750 TPD, around 0.17-0.22 million US$/TPD is applicable. Above 2,000 TPD, 0.13 million US$/TPD is applicable.

These results indicate that thermal plasma gasification processes are more economical if the treatment capacity is increased.

Presently, detailed operational costs of each case are not available other than GS Platech. In addition, there are many methods to utilize byproducts generated during MSW gasification. For example, syngas, which could be used for the generation of high value products such as fuel, chemical compounds, and high purity hydrogen, would work to this effect. This means that, although thermal plasma technology is well-established, there are still many fields to investigate for enhancing the economics of the process.

However, economics will be improved if treatment scale is increased because ofthe following three reasons.

First, the construction cost will be decreased as the capacity is increased, as mentioned above. This will cause a decrease in depreciation cost.

Second, syngas can generate profit as an energy source. Presently, we are abandoning generated syngas because the amounts generated are not sufficient to use as an energy source.

Lastly, the operation of a plant is an economy of scale. As the capacity increases, labor costs, overhead charge, and etc will decrease.

Although the technical feasibility of thermal plasma gasification of MSW has been well demonstrated, it is not presently clear that the process is economically viable on the global market because regional variation of the costs of MSW treatment. However, it is clear that the reuse of vitrified slag and energy production from syngas will improve the comercial viability of this process, and there have been continued advances towards further development of the process.

http://cdn.intechopen.com/pdfs-wm/40402.pdf

PLASMA ARC THE LEADING LIGHT?

Pyrolysis/gasification technology is emerging as one of the most attractive and economically viable ways to manage and treat waste. This includes municipal solid waste (MSW), solid wastes (SW) and/or semi-solid waste (SSW).

A key product from these thermal gasification technologies is the conversion of solid waste into syngas, which is predominantly carbon monoxide (CO) and hydrogen (H2). This syngas can be converted to energy (steam and/or electricity), other gases, fuels and/or chemicals.

Figure 1. Converting MSW, solid waste or semi-solid waste into energy, gases, fuels and Chemicals

The management of MSW, solid waste or semi-solid waste by gasification to syngas can be accomplished in various ways. Figure 1 shows a typical configuration for gasifying MSW or other solid or semi-solid waste into syngas. The syngas can be converted to energy via several methods: A power option to produce steam and/or electricity A chemistry option using catalysts such as Fisher-Tropsch catalysts to produce a wide variety of gases or chemicals such as hydrogen, ethanol, methanol, mixed alcohols, olefins, liquid petroleum gas, kerosene, waxes, ammonia and synthetic natural gas The bio-chemistry approach using specific microbes for the conversion of the syngas into natural gas or fuels such as ethanol, methanol and methane.Performance/thermal efficiency of technologies:For the Thermal Process Technologies discussed, the typical range of process operation is presented in Table 1.

Economic parameters for the five thermal technologies were determined such as capital investment, operation and maintenance, by-product production and sales, and residue produced and costs. Using the parameters of capital investment, plant capacity, energy production, operation and maintenance costs, tipping fee, green tags, energy sales, and by-product residues - an economic analysis was performed to determine the net revenue (before taxes) of each thermal process as shown in Figure 2.

From reviewing the Net Energy Production to Grid of the various types of thermal process technologies in Table 2, plasma arc gasification produces about 740 kWh/tonne (816 kWh/ton) of MSW compared to only about 621 kWh/tonne (685 kWh/ton) of MSW for a conventional gasification technology. Plasma arc gasification can therefore be considered the most efficient thermal gasification process.

Figure 2 suggests plasma arc gasification is the most attractive process for handling solid wastes such as MSW, both in terms of thermal efficiency and economics, although conventional gasification and plasma arc gasification yielded similar results.

Figure 2. Comparison of Various Types of Thermal Processes

Plasma Arc Gasification also combined these attributes: Thermal efficiency Process variety of different solid wastes Minimal pretreatment/presorting of solid wastes Production of syngas for conversion into energy sources such as steam, electricity and/or liquid fuels Environmental appeal as the solid by-product, vitrified slag, can be used as a construction material Environmental appeal from the use of syngas to produce various energy products, while any discharged gaseous effluents can be treated by currently acceptable environmental processes Minimised if not eliminated need for landfill Ability to process and eliminate wastes from existing landfills.Next, the plasma arc gasification process was studied regarding economy of scale to determine what capacity of facility is commercially feasible. For economy of scale analysis, MSW was gasified to syngas and vitrified slag. The syngas was used to generate electricity and the slag used as a road material. The basic plasma arc gasification process being evaluated is represented in Figure 3. Pre-processing is considered minimal for a well-designed plasma arc gasification facility.

Figure 3: Process schematic for producing electricity from MSW using plasma arc gasification

Dr Gary C. Young is an expert in industrial processes and the author of the recently published book Municipal Solid Waste To Energy Conversion Processes; Economic, Technical and Renewable Comparisonse-mail: gycoinc@aol.com

http://www.waste-management-world.com/articles/print/volume-11/issue-6/features/plasma-arc-the-leading-light.html

http://wiki.telfer.uottawa.ca/ci-wiki/index.php/Plasma_Gasification:_A_Clean_Technology

http://en.wikipedia.org/wiki/Plasma_gasification_commercialization

http://www.gasification.org/gasification-applications/chemicals-fertilizers-fuels/

http://www.gasification.org/uploads/downloads/Polygen_chart_2.pdf

Los arcos elctricos son un medio en el cual es difcil operar, y las primeras antorchas de plasma que se usaban no eran confiables para este proceso tan riguroso. Pero actualmente, se ha mejorado la fabricacin de estas antorchas, ya que la calidad de las aleaciones de nquel se ha perfeccionado de manera que las antorchas funcionen de forma continua. Adems de esto, se ha desarrollado un campo llamado Clculo de Dinmica de Fluidos, el cual permite que la basura que est siendo sometida a este proceso de desintegracin se mezcle de tal forma que produzca una mayor cantidad de syngas con la menor cantidad de electricidad posible.http://www.codesin.org.mx/node/279

Como resultado de lo que se ha dicho, la etapa de obtencin de los gases de sntesis se impone como la ms crucial del proceso, dado que permite reducir significativamente los costes generales de produccin de biocarburantes, as como mejorar el rendimiento.

Como conclusin, el proceso de obtencin de los gases de sntesis a partir de plasma parece ser el ms adecuado. Sus costes operativos son equivalentes a otras instalaciones y la gran inversin en equipos inicial se compensa con la alta eficiencia durante la sntesis Fischer-Tropsch en el aumento de la vida y eficiencia de los catalizadores utilizados.

Esta manera de producir biocarburantes podra ser, con tiempo e inversiones adecuadas una alternativa muy interesante para los pases que dependen ahora del petrleo pero tambin a nivel medioambiental, se podra reducir las emisiones de gases de efecto invernadero y aprovechar los desechos humanos.

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