Chemical Engineering December 2019 - 50

U.S. Sulfur Production by Source, 1970-2013
50
45
40
35
30
25
20
15
10
5
Total TPH discharged (kiloton/year)
Total discharged (g/ton throughput)
1969 1974 1979 1984 1989 1994 1999 2004 2009
Year
FIGURE 2. Coinciding with the introduction of waste hierarchy principles,
total petroleum hydrocarbons (TPH) loadings and effluent rates have
trended downwards significantly since the 1970s [3]
Prevention and minimization
On top of the waste hierarchy pyramid
are prevention and minimization.
The best waste-treatment strategy is
to not produce any waste. To enable
waste minimization, there should
be a shift from end-of-pipe treatment
activities to adopting inherently
sustainable
processes throughout
a facility (Figure 4). However, these
efforts require careful planning and
engineering. During the early phases
of a project, decisions are made that
affect the quantity and composition
of waste. However, waste is not exclusively
produced during the operational
phase of the facility. Each phase
of the project, such as construction,
commissioning and startup, can
be included in waste-management
planning. A waste minimization strategy
is not difficult to execute - it
14
12
10
8
6
4
2
1970 1975
1980
1985 1990
1995 2000
Pyrite
Frasch mining
Petroleum refineries
Gas processing
Metal smelters
2005
2010
FIGURE 3. Sulfur is one example of a market where what was previously considered
to be a waste-treatment operation (desulfurization units in natural gas
processing) actually produces a useful raw material [6]
simply needs appropriate attention
and leadership.
There are many ways to incorporate
waste minimization into a project.
To succeed, sustainability efforts
need to be a management priority,
with clear support from a company's
leadership [9]. Sustainability efforts
can be implemented in both newbuild
and in revamp projects. Activities
regarding sustainability should
be assigned to a sustainability coordinator.
For each project phase, a
multidisciplinary team can select the
most appropriate activities to devise
fit-for-project solutions that serve
the environment while maintaining
the project's budget and operational
efficiency. The engineering, procurement
and construction (EPC) contractor
can help support this effort by
providing their expertise and knowledge
of project execution. A sample
of these activities are summarized in
the following sections.
Engineering. Selection of licenses
is part of the process to minimize
waste. During this process, not only
capital expenditure (CAPEX) considerations
should prevail, but also
operating expenditure (OPEX) and
costs of waste disposal and energy
usage. Assuming the installation will
be in operation for at least 20 years,
the costs for resources, disposal
of waste and energy consumption
can have a significant impact on
operational costs.
Construction
Contracts management
Material management
Operations &
maintenance/buildings
Engineering
Office
FIGURE 4. There are opportunities to enact more sustainable operations at every level of an organization
and throughout the entire lifecycle of a project [8]
48
Material management. Receiving
materials and equipment in the
warehouses and laydown areas during
the construction phase of the
project produces large quantities
of shipping packaging. Specifying
packaging materials during the procurement
of the materials and equipment
can avoid significant efforts
related to sorting packaging waste
onsite and ensures the best possible
disposal route - preferably for reuse
or energy recovery.
Construction. Select modularization
techniques to build a large portion of
the project offsite in dedicated workshops
- where waste can be better
controlled, recycled and reused.
Modularization can reduce the activities
onsite and require less shippingrelated
packaging in comparison to
having materials delivered separately
for stick-built installations.
Contracts. Companies should require
contractors to have a sustainability
plan submitted as part of their
technical proposal that is evaluated
as part of an award recommendation.
This plan would include items
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DECEMBER 2019
TPH loads (kiloton/yr)
TPH discharged per throughput (g/ton)
Million metric tons of sulfur content

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Chemical Engineering December 2019

Table of Contents for the Digital Edition of Chemical Engineering December 2019