Task $5$: Absorption $(11$P$)$

Biogas consists of the following compounds: methane, carbon dioxide, nitrogen, oxygen $($see table$).$

For the recovery of methane it should be removed via absorption from the biogas stream in a first

step. The maximum residual load of methane in the biogas stream should be $Y_{,CH4}=0\mathrm{.}25mo\frac{l}{m}ol$

after the absorption process. The removal of methane is carried out with absorption process using an

ionic liquid $($IL$)$ as absorption media. The absorption media after the desorber holds a residual load of

$x_{,CH4}=0\mathrm{.}08mo\frac{l}{m}ol$ before entering the absorption column. Additionally assume that only methane

is absorbed$.$

Composition of biogas:

f$)$ Draw a flow chart for the scrubbing of flue gas with all relevant streams and loads $($absorption

and following desorption$).(3$P$)$

g$)$ Determine the minimum stream of absorbent media. The volumetric flow rate of the carrier gas

stream is $G_0^{}=100$kmo$\frac{l}{h}.(2$P$)$

h$)$ Determine the number of theoretical stages for the absorption process. The real solvent ratio is

$1\mathrm{.}6$ times the minimum solvent ratio. $(3$P$)$

i$)$ Methane is to be regenerated with a pure stripping agent. Draw a possible operating line

$("$Arbeitsgerade$")$ for the desorption process as a dashed line in the given load diagram. $(2$P$)$

j$)$ Because of an error in the desorber, the IL holds a higher residual load of $x_{,CH4}=0\mathrm{.}24mo\frac{l}{m}ol$

before entering the absorption column. What follows for the absorption process with a constant

solvent ratio? Quantify your result with an exact value. $(1$P$)$