(558bx) An Integrated Approach for Capturing and Utilizing CO2 in Pulp and Paper Mills: Preliminary Economic Assessment of CO2 Capture from Lime Kiln Operations

In pulp and paper mills, a lime
kiln is used to convert lime mud (CaCO3) into lime (CaO) for reuse in the
causticizing plant of the kraft recovery process. In this operation, lime mud
is fed into a rotary kiln where it is dried and heated counter-currently by
combustion gases from an oil or gas burner at the other end of the kiln. As the
mud temperature reaches around 1150-1250°C in the calcination zone of the kiln,
CaCO3 decompose into CaO and CO2. The resulting CO2 is emitted as a source of greenhouse
gas. On the other hand, precipitated calcium carbonate (PCC) is widely used as
fillers in papermaking to reduce the production cost and improve the paper
properties such as opacity and brightness. One of the processes to produce PCC is
to slake quicklime (CaO) with water to form calcium hydroxide (Ca(OH)2). The
resulting calcium hydroxide is carbonated with CO2 to generate a suspension of
CaCO3 which is subsequently filtrated, dried and deagglomerated in grinders.

This work focuses on feasibility
analysis of CO2 capture from lime kiln exhaust gas for utilization in PCC
production. Chemical absorption using an amine absorbent is considered for CO2
capture. We developed a simulation of the chemical absorption-desorption
process in ASPEN Plus and performed preliminary techno-economic analysis (TEA)
for the combined CO2 capture and utilization process. We studied the impact of changes
in design and operating conditions of the amine-based CO2 capture process on
the TEA results via sensitivity analysis. This presentation will discuss the
results of TEA and sensitivity analysis for CO2 capture from a lime kiln
operation.