Moreover, the at least two, at least three, or preferably at least four feed lines can enter the reactor block individually, as shown for example in FIGS. 4A through 4F, and in FIG. 5A, and can be sealed using epoxies or other sealants (not shown), or using individually mounted mechanical fittings (e.g., individual swage-lock type fittings, not shown) mounted in the feed ports 515 of the reactor b