Inherently
Safer Design (ISD) describes a strategy that reduces
and even eliminates inherent hazards in processes. However, ISD principles
improving inherent safety always involves tradeoffs between these
two competing factors: safety and costs. In inherent safety aspects,
process intensification (PI), one of the methodologies in ISD, aims
to eliminate units and simplify the process. Therefore, synchronous
promotion of cost-efficiency and safety is achieved. Nevertheless,
applying PI strategies in the design stage may result in adverse safety
effects, and eliminating units may cause risk transfer and risk accumulation,
which could lead to serious consequences when accidents occur. In
this study, we introduced a novel methodology involved in a better-suited
indicator, Advanced Comprehensive Inherent Safety Index (ACISI), along
with Quantitative Risk Analysis (QRA) to evaluate the safety performance
of PI designs in the early stage. To further illustrate, a case study
of C3-alkyne selective hydrogenation distillation process
is selected to analyze safety and economic impacts on four intensified
designs (reactive distillation, thermally coupled distillation of
a side-rectifying section, thermally coupled distillation of a side-stripping
section, and fully thermally coupled distillation) using the proposed
methodology. Moreover, the safety performance of individual units
in each process is explored. Investigation of the case study found
that potential root causes for risk transfer are related to the vapor–liquid
flow profiles in the column. Considering PI features and risk transfer,
this study provides a generally effective framework to evaluate process
safety quantitatively and to explore safety characteristics comprehensively
for different intensified processes, thus better assisting the achievement
of ISD through PI.