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nitrdgeno en el propio sitio elimina 10s costos fijos de
transporte y distribucibn responsables por una gran
proporci6n de 10s costos de1 fertilizante.
La producci6n de1 fertilizante a nitr6geno en el
propio sitio tambien permite el uso de parte de1 calor
desperdiciado en el proceso para otros usos de la
granja asi coma el secado de la cosecha, calefaccidn
de1 aire y agua, etc. El sistema ilustrado en el
diagrama de la Fig. 1 csti en plena instalaci6n actual
en una granja experimental de la Universidad de
Nevada, cerca de Austin, Nevada, USA.9 En esta in-
stalacidn prototipo, el calor que se desperdicia serti
utilizado para atemperar un invernadero para ex-
tender la e&a&n de1 crecimiento de las plantas.
Arco Reactor
El nlicleo de1 sistema de produccicin de1 fertizante a
base de nitr6geno que se esti desarrollando es el
reactor de arco elktrico donde se combinan el
nitr6geno y el oldgeno de1 aire para producir 10s 6x-
idos de nitr6geno de acuerdo a las siguientes reac-
ciones:
N2 + 02-2NO AG = + 41.4 Kcal
2N0 + 02-2N02
AG = - 16.6 Kcal
La reacci6n en dos pasos, una reacci6n en-
dot&mica seguida por una reacci6n exotkrmica que
es favorecida por el rkpido enfriamiento de 10s gases
calientes, es necesaria para producir el bibxido de
nitr6geno que puede ser captado en agua para for-
mar $cido nitrico (HN03) y Bcido nitroso (HN02).
Cuando esta solution kida se pasa a travks de una
columna conteniendo cal curubicada (CaCO$, se pro-
duce el fertilizante a base de nitrato de calcio. Alter-
nativamente, si se pasa la soluci6n a trave& de una
columna de fosfato de rota, se puede producir ambos
fertilizantes, el de nitrato de calcio y el de fosfato,
utilizando el mismo equip0 bdsico.10
El tipo de diseAo del reactor de arco ekctrico selec-
cionado para nuestros estudio prototipo iniciales es
una forma modificada de un reactor de arco con
vortex estabilizado conforme se ilustra en una vista
de torte lateral en la Figura 2. El reactor se con-
struye comenzando con un caiio standard de hierro
negro con dimensiones de aproximadamente 8 cm de
digmetro y 1.5 met.ros de largo, que sierve coma un
electrode. Un Segundo electrode, consistente en una
variila de hierro solid de aproximadamente 4 cm de
diametro y 25 cm. de largo, se monta conckkica-
mente a trave de un aislador a un extremo de1 caiio.
Se introduce aire a trave de 10s puertos tangenciales
de entrada al &o para crear corrientes de aire que
243
tilizer costs. On-site production of nitrogen
fertlilizer also permits use of some of the waste
heat of the process for other farm uses, such as
crop drying, space heating, water heating etc.
The system shown in the flow diagram, Figure 1,
is presently being installed on an experimental
farm of the University of Nevada near Austin,
Nevada, USA.9 In this prototype installation, the
waste heat will be used to heat a greenhouse to
extend the growing season,
Arc Reactor
The heart of the nitrogen fertilizer production
system being developed is the electric arc reac-
tor where the nitrogen and oxygen of air are com-
bined to produce nitrogen oxides according to
the following reactions:
N2 + 02-2N0 AG = + 41.4 Kcal
2N0 + 02-2N02 AG = - 16.6 Kcal
The two step reaction, an endothermic reaction
followed by an exothermic reaction that is
favored by rapid quenching of the hot gases, is
necessary to produce the nitrogen dioxide which
may be trapped in water to form nitric (HN03)
and nitrous (HN02) acids. When this acid solu-
tion is passed through a column containing
crushed limestone (CaCOa), calcium nitrate
fertilizer is produced. Alternatively, if the solution
is passed through a column containing rock
phosphate, both calcium nitrate and phosphate
fertilizer may be produced using the same basic
equipment.10
The type of electric arc reactor design selected
for our first prototype studies is a modified form
of a vortex stabilized arc reactor as shown in
cross-section view in Figure 2. The reactor is con-
structed starting with a standard black iron pipe
with dimensions of about 8 cm. diameter and 1.5
meters length which serves as one electrode. A
second electrode, made from a solid iron rod of
approximately 4 cm. diameter and 25 cm. length
is mounted concentrically through an insulator at
one end of the pipe. Air is introduced through
tangential inlet ports in the pipe to create swirl-
ing eddy currents of air near the second elec-
trode resulting in the production of a vortex-
shaped arc. The action of the vortex arc creates
eddies of cooler air near the walls of the pipe as
well as a slight pressure gradient directed radial-
ly towards the center of the pipe, thereby tending
to constrain the arc path along the axis of the