Kraft pulp mill scale control with end group modified polycarboxylates

Abstract

Scale build-up on metal surfaces of a black liquor evaporator is prevented or mitigated by treating the black liquor with a deposit inhibiting concentration of a water-soluble polymer containing a polycarboxylate chain and a 3-mercaptopropionic acid end group.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. provisional application Ser. No. 62 / 869,235 filed Jul. 1, 2019, the disclosure of which is incorporated by reference.TECHNICAL FIELD[0002]The present disclosure generally relates to scale control in the Kraft process for paper making, and more particularly relates to antiscalants for use in the black liquor concentration process.BACKGROUND[0003]The kraft pulping process is one of the major pulping processes in the pulp and paper industry. Spent liquor resulting from the kraft pulping process (black liquor or “BL”) contains various organic materials as well as inorganic salts, the deposition of which detracts from an efficient chemical recovery cycle. Inorganic pulping chemicals and energy are recovered by incinerating BL in a recovery boiler. For an efficient combustion in the recovery furnace, BL coming from the pulp digesters with relatively low solids concentration has to be evaporated and co...

AI Technical Summary

Benefits of technology

The patent text describes a study that tested different anti-scalants to see if they could prevent scale buildup in a system. The results showed that some of the anti-scalants were effective in preventing scale buildup. The technical effect of this patent is to provide a solution for reducing or preventing scale buildup in a system, which can cause damage and reduce efficiency.

Problems solved by technology

Kraft pulp mill evaporator systems can be the bottleneck in chemical recovery limited mills.

These are water soluble but cause evaporators at the high concentration end to lose efficiency quickly, especially in mass crystallization events that can occur every few days.

On the other hand, burkeite, which precipitates when total solids concentration reaches approximately 50%, represents a specific problem of evaporators and concentrators.

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