Ideal Flow Reactors - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 189

Thus,

1 f A ¼ ln 1 f Ae

f Ae

Z

1
k

d f A

t ¼ (E5-2.12)

k

0

Plug in the numbers,
t ¼ ln 1 f Ae
k

¼ ln ð 1 0 : 2 Þ

0:254=min ¼ 0:8785 min

3. The space time is defined as the reactor volume divided by the inlet volumetric flow rate,

V
Q 0

s ¼

(E5-2.13)

In part (a), we have obtained the values for V and Q 0 . Substituting V and Q 0 into the above
equation, we obtain

80:429 m 3
1:38246 m 3

V
Q 0 ¼

s ¼

s ¼ 58:18 s

¼ 0:9696 min

=

4. One can observe that t . This is due to the change of flow rate or density of the reaction

mixture in the reactor. As the reaction mixture density decreases in the reactor, the
volumetric flow rate (or flow velocity) increases and the residence time decreases. The
space time, however, is defined based on the inlet flow rate.

ss

5.3. GA SIFICATION AND FISCHER e TROPSCH TECHN OLOGY

Before leaving the tubular reactor discussions, let us examine the promising gasification
and synthesis reactions and their reactors. This is a process in which the carbon and
hydrogen raw material sources were first converted to basic building block chemicals: CO
and H 2 and polymerize together to produce desired products.
n CO

þ 2n H 2 / ð CH 2 Þ n þ n H 2 O (5.26)

This process was discovered and developed primarily in Germany during World Wars I
and II to provide synthetic liquid fuels to compensate for the Allies blockade of crude oil
shipment. [The argument can be made that both world wars were essentially fought over
access to petroleum in the Caucasus region of Russia and the Middle East. The U.S. blockade
of Japanese access to Far East crude oil was a major factor in Japan declaring war on the
United States with the bombing of Pearl Harbor. These arguments are summarized in
the topic The Prize by Daniel Yergin.]
Fischer e Tropsch (FT) technology has been practiced on a large scale in South Africa
because of the need for an independent source of liquid fuels during their political isolation,
and they had abundant coal to make syngas. However, these processes are potentially an
exceedingly important replacement for liquid fuels to use when crude oil supplies are