The prehydrolysis kraft process works well for wood (is the standard) but it is not needed for jute due to the much lower lignin content. I suggest trying the prehydrolysis soda (NaOH) process. This will make chemical recovery easier and less expensive in a commercial mill.
Also, post cooking "bleaching" with just a cold alkali extraction may not be sufficient for high alpha cellulose. You may want to look at ozone and/or alkaline peroxide.