▁external ▁cool ing ▁jack ets ▁are ▁generally ▁preferred ▁as ▁they ▁make ▁the ▁vessel ▁easier ▁to ▁clean . ▁The ▁performance ▁of ▁these ▁jack ets ▁can ▁be ▁defined ▁by ▁ 3 ▁parameters : ▁ ▁response ▁time ▁to ▁modify ▁the ▁jack et ▁temperature ▁ ▁uniform ity ▁of ▁jack et ▁temperature ▁ ▁stability ▁of ▁jack et ▁temperature . ▁ ▁It ▁can ▁be ▁argued ▁that ▁heat ▁transfer ▁coefficient ▁is ▁also ▁an ▁important ▁parameter . ▁It ▁has ▁to ▁be ▁recognized ▁however ▁that ▁large ▁batch ▁react ors ▁with ▁external ▁cool ing ▁jack ets ▁have ▁severe ▁heat ▁transfer ▁constraints ▁by ▁virtue ▁of ▁design . ▁It ▁is ▁difficult ▁to ▁achieve ▁better ▁than ▁ 1 0 0 ▁W att s / lit re ▁even ▁with ▁ideal ▁heat ▁transfer ▁conditions . ▁By ▁contrast , ▁continuous ▁react ors ▁can ▁deliver ▁cool ing ▁capac ities ▁in ▁excess ▁of ▁ 1 0 , 0 0 0 ▁W / lit re . ▁For ▁processes ▁with ▁very ▁high ▁heat ▁loads , ▁there ▁are ▁better ▁solutions ▁than ▁batch ▁react ors . ▁ ▁Fast ▁temperature ▁control ▁response ▁and ▁uniform ▁jack et ▁he ating ▁and ▁cool ing ▁is ▁particularly ▁important ▁for ▁cry st all ization ▁processes ▁or ▁operations ▁where ▁the ▁product ▁or ▁process ▁is ▁very ▁temperature ▁sensitive . ▁There ▁are ▁several ▁types ▁of ▁batch ▁re actor ▁cool ing ▁jack ets : ▁ ▁Single ▁external ▁jack et ▁ ▁The ▁single ▁jack et ▁design ▁consists ▁of ▁an ▁outer ▁jack et ▁which ▁surr ounds ▁the ▁vessel . ▁He at ▁transfer ▁fluid ▁flows ▁around ▁the ▁jack et ▁and ▁is ▁inject ed ▁at ▁high ▁velocity ▁via ▁no