TBP01x 6.5 Technology improvement
Welcome back!
Glad you can join us again.
In this short unit we are going to review our process in the light of sustainable development
and see where the opportunities are for technology improvements.
Shared concerns about the state of environmental, economic and social dimensions of
today s and tomorrow s world are expressed through the concept of sustainable
Development. The journey towards sustainability finds production and consumption at its
very heart.
It also relates to the social responsibility of organizations and the objective to improve social
and environmental performances along with sustained economic profitability all in the
perspective to contribute to greater human well being.
One of the earliest attempts to describe the role of multiple factors in determining
environmental degradation was the IPAT equation. Environmental impact (I) referred to
resource depletion or waste accumulation; population (P) to the global size of the human
population; affluence (A) to the level of consumption by that population; and technology (T)
to the processes used to obtain resources and transform them into useful goods and wastes.
If we wish to half the global impact in 2050 referred to 2000, and we know that the
population is predicted to increase by that time with 50%, and that the consumption grows
with a factor 5, this means that we have to substantially reduce the impact of our
technologies used to produce our food, feed and other necessary materials. So the pressure
is on!
Let us review how technology for biobased production can contribute to this and where the
opportunities for further improvements are.
Looking at John s analysis on the environmental impact as shown in unit 6.3, we see a
number of main contributors to the use of non renewable energy (NREU) and emission of
greenhouse gasses (GHG). From the LCA table we see that the large impacts are from sugars;
ammonia; metabolic side products; waste water treatment and steam.
Very obviously the amounts of sugar in the process are large and have a major impact. That
emphasises that sugar yield is very central. Not only in the conversion, but also from the
production in the field. The impact can be seen as a considerable cost contributor (see unit
6.2), but also in terms of its contributions to non renewable energy and GHG per kg PDO. To
reduce these effects we have the options to use better adapted strains in the process to
increase the conversion yield. The impact can also be reduced by a higher yield per hectare,
with a potential lowering of the price and environmental footprint. This could be done by
dedicated improved production crops, for example by using genetic modification techniques
and / or by utilising the agricultural residues in second generation technology.
In the LCA table we also see a number of metabolic side products such as glycerol. Even
though their concentrations and amounts are modest, their cumulative use of non
renewable energy exceeds those of sugar by far, and their GHG impact matches that.
Improving the metabolic pathways of the micro organisms used in the fermentation can
have a substantial direct impact. This will also lower the Downstream Processing efforts to
produce PDO on spec, from a much less contaminated fermentation broth. And therefore
has significant effects on the process economics both in CAPEX and OPEX terms.
Ammonia is the nitrogen source for the microbial biomass. It costs a lot of non renewable
energy to produce and you can see in the LCA that although it is used in much smaller
quantities, the impact on use of non renewable energy is similarly large! In current process
options, it is dealt with via the waste water treatment system, and in fact converted to
(relatively harmless) Nitrogen gas. However, options to recover and recycle nitrogen as
ammonia for the process or ammonium nitrate which can be used as fertiliser can have a
significant impact on the use of non renewable energy, as well as on GHG emissions. To
make this competitive, the water streams should be more concentrated so that the recycling
can be added to the process!
Wastewater treatment is another large contributor to GHG emissions and use of non
renewable energy. Again improved GM strains with a tolerance to higher product
concentration could help to reduce the water use and can also lead to increasing recycling
options for resource recovery in the more concentrated streams and to lower CAPEX and
OPEX.
Electricity and especially steam have a large impact and are used at many places in the
operation.
Clearly energy and heat integration are an important target in analysing process
optimization options and might result in significant reduction of the production costs and
environmental impacts. In this respect it might be also interesting to explore options for
collaboration with neighbouring industries to share access steam. The process design should
be optimized for the best candidates for improvement.
Transport of feedstocks (and also of products) can be a considerable component of the
NREU and GHG aggregated values for sugar. Obviously location of the process unit is an
important factor, but calculations on economics and environmental impact could also help
in exploration of the most optimal scale of the process operation.
Concluding this unit we have seen that LCA helps in clearly identifying the opportunities for
improvement in addition to economic analysis done in module 5 and unit 6.2.
It underlines that opportunities for improvement can be biological (metabolic engineering),
as well as in process engineering, and that these should be seen in context of the whole
process.
Furthermore, further analysis of scale and location, including options for sharing of rest
streams and optimising energy balances with neighbouring industries can be done to even
further improve the overall design.
And that is of course why we included this integral economic and LCA analysis in this course
 Technology for Biobased Products .
In our next and last unit we will go deeper into some of the more social issues.
I hope you will join us in the next unit!