Page 426 - Design of Simple and Robust Process Plants

10.2Continuous Improvement of a High-quality Plant 413
periods. The capacity performance limitations are divided into categories, to register
causes of deviations from its maximum demonstrated capacity. For example, the
categories for a lower than demonstrated capacity might be:
. market demand,
. mechanical failures,
. process failures,
. process availability (regeneration, shut-down),
. equipment availability in multi-purpose usage,
. logistic constraints,
. low quality performance.

The measurement results show not only the capacity gaps but also the opportunity
gaps for improvements under the different categories. It will be clear that the targets
for these gaps need to approach zero. The approach for these opportunities will be
discussed below. The logistic and business opportunities are excluded, as these are
not a production plant responsibility.
10.2.2
Process Reliability and Availability

Plant reliability and availability (Bascur et al., 1997) can be divided into the process
and mechanical causes for production loss. Process, as well as mechanical, causes
need to be analyzed for: grass root causes; common causes and frequencies of occur-
rence on similar items (pumps, temperature measurements, fouling, etc.); mean
time to repair (MTTR); mean times to stop and recover production; and production
losses.
The analysis of the process failures/losses (a lower production rate due to process
reasons also falls under this category) might be done in concert with research. Typi-
cal causes for process failures/outages/losses are:
. fouling,
. regeneration of catalyst,
. cleaning or washing steps,
. sterilization,
. product changes.
The opportunities need to be quantified money-wise. Multiple functional thinking
needs to be applied to generate creative economic solutions or areas for further
investigations. The solution of these types of problem is time-consuming, but they
often have short pay-back times.
Mechanical failures are easier to recognize, but it is more difficult to find the root
cause. The investigators often have a traditional maintenance background and so
have a tendency to blame the equipment and repair it (Figure 10.1). A good
approach is to appoint a production engineer for the grass root analysis, but to have
maintenance and process engineering experts in the team. The analysis emphasizes
the same elements as mentioned above, but it will contain some additional elements