# the volume in hydraulic retention time is of reactor/container or liquid

I have a tiny reactor, and the volume I need is 425ml. If there is no/few other reactants, then the volume in hydraulic retention time is clear: reactor/container's volume. and hrt is V/u(V is 425ml, u is flow rate) But if I fill 80% of container with something like lime mud, the real volume of water is only 20% left -- 85ml. How is my V should be? 425 or 85ml? IOW, the volume in hydraulic retention time is of reactor/container or liquid?

• The usable volume.. ie that not filled by mud. – Solar Mike Apr 17 at 10:11

## 1 Answer

Water volume is 85 ml now, so the hrt is 85 ml/u. The liquid retention time because the mud doesn't react, right?

• because the mud doesn't react IMO, it's not right, because the mud will release Ca2+ – 陳 力 Apr 18 at 1:22
• Then you should consider the mud to calculate the hrt. – user20096 Apr 19 at 1:10