Soap removal at southern kraft mill using centrifugal separation, 19PEERS

A trial was conducted at a southern pine kraft mill using a centrifugal separator to separate extractives-rich soap from black liquor. Intermediate black liquor from the fourth evaporator effect was diverted from the feed to the existing soap skimmer tank to a centrifugal separator. The undissolved CTO (crude tall oil) component of the soap was fully removed from the black liquor across the design flow range of the separator. The feed flow to the separator was increased until detectable levels of CTO were measured in the separated black liquor (BL). The removal efficiency of the separator was stable across a wide range of soap content levels in the light phase discharge of the separator.   

A case study is presented for a 1100 ODST/D southern pine kraft line comparing two scenarios for soap removal from intermediate BL, i) soap skimming tank separation and ii) centrifugal separation. BL and CTO balances are presented for both options. The balances include both the undissolved (recoverable) and dissolved (unrecoverable) CTO components in the BL. The results demonstrate enhanced soap removal can result in significant gains in tall oil production. For recovery boiler limited kraft mills, incremental gains in pulp production are available which can amount to several million in additional revenue for the mill. 

TAPPI conference proceedings and presentations, technical papers, and publication articles provide technical and management data and solutions on topics covering the Pulp, Paper, Tissue, Corrugated Packaging, Flexible Packaging, Nanotechnology and Converting Industries.

Simply select the quantity, add to your cart and your conference paper, presentation or article will be available for immediate download.