**8. References**


that they depend on their concentration in water. They exhibit a minimum around 20% of volumetric concentration. These results indicate that scrubbing systems should work around 7.5% for applications where H2S removal is the main concern or higher than 50% where CO2 removal is the main objective. On average at 7.5% of MEA or DEA concentration in water their absorbing capacity is of 5.37 and 410.1 g of H2S and CO2, respectively, per Kg of MEA

Using this information, it was designed an absorbing gas-liquid column to reduce the H2S and CO2 content to 100 ppm and 10%, respectively, from ~60 m3/hr biogas streams, with negligible pressures drop. The manufactured column was tested with three different types of amines: MEA, DEA, and MDMEA. Results permitted to identify the ratio of amines to biogas flow (*Qr*=230) required to obtain the highest H2S and CO2 removing efficiencies ( 98% and 75% respectively) along with the highest mass transfer in the column (86%) when it is

Then, an amine regenerative system was designed, manufactured and tested. Exhaust hot gases from the engine were used to heat the diluted amine up to 95ºC. Tests showed that the H2S removing efficiencies change from 98% to 95% when the amine is regenerated. Similarly, it changes from 87% to 50% for the case of CO2. Even though these results are encouraging, they are still partial results in the sense that further work is required to ensure

Finally, an economical analysis was performed assuming a horizon time of 10 years and a scale of power generation of 1 kW in a typical farm in Mexico without any governmental subsidy or benefits from green bonuses. It was found that under these circumstances, electric power generation from biogas has a cost of 0.024 USD/kW-h. This cost can be reduced up to 61% (0.015 USD/kW-h0 when the amine based H2S and CO2 biogas scrubber is included). Then, it was found that the turnover of the initial investment is of about 1 year.

This project was partially financed by the Mexican council of science and technology-COMECYT and the company MOPESA. The authors also express their gratitude to engineer

Carrillo, L. (2003). *Microbiología Agrícola*, Universidad Nacional de Salta, ISBN 987-9381-16-

Cengel, Y. & Boles, A. (2008). *Thermodynamics. An Engineering Approach* (6th Ed.), McGraw-

Chakravarti, S.; Gupta, A. & Hunek, B. (2001). Advanced Technology for the Capture of

Montes, M.; Legorburu, I. & Garetto, T. (2008). *Eliminación de Emisiones Atmosféricas de COVs por catálisis y adsorción*, CYTED, ISBN 978-84-96023-64-2, Madrid, Spain Davis, W. (2000). *Air Pollution Engineering Manual*, Wiley Interscience Publication, ISBN 978-

DePriest, W. & Van Laar, J. (1992). *Engineering Evaluation of PRENFLO-based Integratedgasification-combined-cycle (IGCC) power plant designs*, Chicago, Illinois, USA

Carbon Dioxide, *First National Conference on Carbon Sequestration*, Washington, DC,

Hill, ISBN 9780073305370, New York, New York, USA

maximum amines regeneration before evaluating its removing efficiencies.

or DEA.

used MEA at 9%.

**7. Acknowlegments** 

**8. References** 

Jessica Garzon for their contributions to this project.

5, Salta, Argentina

USA, May 15-17, 2001

0-471-33333-3


**8** 

*2ProdAl scarl,* 

*Italy* 

*University of Salerno,* 

**Mass Transfer Enhancement** 

**by Means of Electroporation** 

*1Department of Industrial Engineering,* 

Gianpiero Pataro1, Giovanna Ferrari1,2 and Francesco Donsì1

PEF treatment involves the application of repetitive ultra-short pulses (from ns to s) of a high-strength electric field (0.1-10 kV/cm) through a material located between two electrodes. The application of the external electric field induces the permeabilization of cytoplasmatic membranes. The main advantages of PEF with respect to other treatments addressed to disrupt the cell membranes, such as the application of heat or the addition of

 Cost reduction due to lower energy consumption and unnecessary enzyme addition Higher purity of the extracts, since upon the PEF treatment the permeabilized cell membranes maintain their structural integrity and are not disrupted in small fragments

The application of PEF as a permeabilization treatment to increase the rates of mass transfer of valuable compounds from biological matrices was demonstrated to be effective in drying,

This chapter reviews the basic mechanisms of PEF-induced permeabilization of plant tissues, discusses the methods of detection of electrically induced cell damages and analyses the influence of PEF process parameters on mass transfer. Furthermore, mathematical models to describe the mass transfer rates from PEF-treated vegetable tissue are discussed and some criteria of energy optimization are given as well as some examples on the recovery of polyphenolic compounds from food matrices and on the integration of PEF

The application of pulsed electric fields to biological cells (plant or animal) mainly affects the cell membranes, inducing local changes in their structures and promoting the formation of pores. This phenomenon, named electroporation (or elecropermeabilization), causes a drastic increase in the permeability of cell membranes, which lose their semipermeability, either temporarily or permanently (Weaver & Chizmadzhed, 1996). Electroporation is today widely used in biotechnology and medicine to deliver drugs and genes into living cells

Lower processing times thanks to the increased mass transfer rates.

**1. Introduction**

pectolytic enzymes, are as follows:

extraction, and diffusion processes.

treatments in the winemaking industry.

**2. Basic considerations and mechanism** 

