The need for sustainable development of our society that balances social, environmental and economic aspects is bringing major developments in chemical and processing industry. Priorities are slowly but surely changing, new products and technologies are being developed, old technologies are being revised and new perspectives for existing processes are being defined.

What does it mean - "A sustainable development for chemical and processing industry"?

By the definition, sustainable development is a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development and institutional change are made consistent with future as well as present needs. Sustainable development is the development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. (Ref: Our Common Future, commonly called the “Brundtland report”, WCED 1987).

The key point of the concept is that the main focus is not only an economic, a financial one, but also responsibility towards social and ecological environment as well, or “triple P”: needs of people, planet and profits aiming towards balance (Sustainable Development in the Process Industries - Cases and Impact, Harmsen & Powell, 2010)

One of the most exciting effects related to chemical engineering is that sustainable development is solid ground and a driver of innovation and development and it will continue to be one still years to come as the society is making steps towards balanced industry and more acceptable ways of living. 

For all these new technologies and products in accordance with environmental and social requirements to be brought to the market, the fact is that these new choices must perform as well as or better than previous alternatives, and at the lower cost.

The challenges are addressing chemical engineers hugely, because a chemical engineer is an ‘enabler’; someone who makes things happen efficiently on a massive, industrial manufacturing scale with the aim to get the best results at the least cost and with the lowest impact on the environment possible. The ability of chemical engineers to combine knowledge of chemistry, physics, mathematics and economics and apply it in reality, is what makes them invaluable where there is any development happening.

In order to seek and develop products and technologies of sustainable development, goverments and organizations are providing programs and guidlines to direct development and innovation, so key points of challenge for chemical engineers are:  

• Preventing waste,
• Designing safer products,
• Designing less hazardous chemical syntheses,
• Using renewable feedstocks,
• Using catalysts instead of stoichiometric reagents,
• Using safer solvents and reaction conditions,
• Designing products and processes to maximize mass and energy efficiency,
• Implementing real time analysis and control to monitor and prevent pollution,
• Minimizing the potential for accidents,
• Minimizing energy and materials consumption in the separation and purification steps,
• Promoting recycling,
• Optimizing heat and material integration,
• Where plausible, products, processes, and systems should be designed for use in a commercial “afterlife",
• Using renewable material and energy inputs where possible.

The focus is on the idea that biological systems can provide models for the design and functioning of industrial systems by using the wastes from one process as useful inputs to another. 

Process engineering of the twenty first century

The engineering challenge in line with the key directions of the development in process engineering for the twenty first century can be summarized into the following points:

1. Dwindling fossil resources and increasing concern about global climate change and other environmental concerns will make this century a transition period from a fossil past to renewable future resources.
2. This change will necessitate reconstruction of much of the process industry that currently provides energy services and materials for society, as the types of raw material define the technologies that are utilizing them.
3. This reconstruction will affect not only the technologies used, but also the structure of the industry and the logistical system employed in material flow management.

Therefore, the challenge for chemical and other engineers is to optimize the transformation of renewable resources into products and services for society, from raw material generation to the conversion of raw materials to products, and the reintegration of waste and by-products in a meaningful way. Thus, the process to be designed should be optimized and defined in a most efficient way regarding resources and energy consumption and with the respect of the entire cycle from raw material generation, to production processes, to recycle and/or reuse. 

So what are the products and technologies that support the strategy of sustainable development and what are the skills of chemical engineers that can support the progress?

Biomass conversion

The thermochemical processes aim is converting biomass into heat, electricity and liquid or gaseous biofuels. Besides combustion of biomass, two technologies that came into focus are gasification and pyrolysis of the biomass because of th variety of products they are able to produce.

Gasifiation

The gasification processes produce a syngas from biomass due to a controlled input of oxygen, which is roughly one-third of the amount of air required for combustion stoichiometry. The syngas is polluted with tar, by-products of gasification. Therefore, it should be cleaned to
reduce its tar content for further valorization. The syngas could be used in gas engine to produce heat and power. It could be converted by catalysts to liquid biofuels, Fischer–Tropsch diesel or methanol, or to gaseous products, CH4 or H2.

Pyrolysis

Pyrolysis produces, by the action of heat and in an inert atmosphere, without any oxygen, a char, a bio-oil and a syngas. Char could be further used in gasification processes (such as biomass) or for higher added-value options (e.g. activated carbons). The bio-oil, which is a complex liquid of hundreds of oxygenated molecules, could be converted by special catalysts
to biofuels or chemicals. 

Biorefineries and sustainable biofuels 

To assess the sustainability of biofuels, all stages of the fuel value chain have to be considered, from feedstock production and supply, fuel production and distribution, and vehicle operation. Only an assessment of the entire value chain allows a fair comparison of different fuels and comparison of different technologies to make the same fuel.
After the first generation of biofuels has come to an end because of their limitations, utilization of lignocellulosic materials found as the residues of the agriculture and forestry has come into focus. 
Lignocellulosic biomass is fairly cheap to produce, certainly compared to food crops. However, its conversion to liquid biofuels requires large investments.
The main goal of the processes is to remove selectively (by catalysts) the oxygen present in biomass to produce liquid hydrocarbon-based biofuels that match the specifications of engines developed for petroleum-based fuels. 
After pretreatment steps, biomass can be converted to syngas by gasification to produce the alkanes or bio-oils by fast pyrolysis or liquefaction. The bio-oil is then catalytically deoxygenated by specific catalysts. Bio-oils may be coprocessed with petroleum oil if the catalytic processes of the current refineries are adapted. 

The main interest of this second route is that the existing infrastructure of petroleum refineries is well suited for the production of biofuels. It may allow a more rapid transition to a sustainable economy without large capital investments for new reaction equipment. 
Cellulosic biofuels are slowly becoming reality with first plants being in operation. The biomass supply fields have been identified, logistic issues are being addressed, sustainability criteria are being developed, conversion technology is being demonstrated and governments are adjusting their support to the “sustainability” performance of the biofuels. However, still more needs to be done to allow large - scale deployment at affordable cost and in a sustainable manner. Further improvements are needed throughout the entire value chain, from biomass production to fuel distribution and certification. 

Bioplastics world - an alternative to petroleum based plastics

Biodegradable plastics were introduced in the 1980s as possible renewable feedstock in producing non-petroleum-based plastics, as well as to reduce environmental problems.  In order to reduce the environmental impact of plastics (especially in terms of CO2 released in the environment) some of the products obtained from agriculture (starch, cellulose, wood, sugar) are used as raw materials. By this way, the net balance of carbon dioxide is greatly reduced, since the CO2 released during production, utilization, and disposal of plastics is balanced by the CO2 consumed during the growth cycle of the plant. Furthermore, petroleum, with constantly rising prices, is replaced by renewable raw materials obtained from agriculture. The use of bioplastics was also stimulated by a second environmental motive, related to problems connected with the disposal of waste. 

In principle, the range of available bioplastics can already cover many fields of application today. In practice, however, processing problems often still arise and need to be addressed.

By-product synergy networks

"By-product synergy networks" are standing for reduction of waste by using output from one company into a product stream for another company can generate revenue while reducing both emissions and the need for fresh energy stream materials The underlying concept relevant to industrial ecology is that everything used by a member of an ecosystem has a potential use elsewhere in the network.
BPS can offer true business opportunities beyond cost reduction if wastes are viewed not as wastes but as raw materials for other industries. As by-product synergy networks develop, industry goals may shift from reducing waste generation toward producing zero waste and finally to producing 100% product, all while lowering emissions and reducing energy use.
Maintaining a life-cycle perspective allows for analysis that extends beyond one facility or industry and considers all the economic and environmental impacts of the products.

New required skills of chemical engineers

Therefore, as can be concluded from the discussion above, new technologies not only have to be optimized and production scales increased, but also substantial progress in the technologies is necessary. When talking about neccesary engineering skills, modeling, simulation, and accompanying sustainability assessment will play a crucial role in achieving full exploitation of the potential of those new technologies.

References:

Sustainable Development in the Process Industries: Cases and Impact, J.Harmsen, J.B. Powell, AiChE, John Wiley&Sons, Inc., 2010

Thermochemical Conversion of Biomass for the Production of Energy and Chemicals, A. Dufour, John Wiley&Sons, Inc., 2016

Sustainable Development in Chemical Engineering Innovtive Technologies, V.Piemonte, M.de Falco, A. Basile, John Wiley&Sons, 2013

About Ivana

Ivana is a Ph.D. in Chemical Engineering and director of a family company. Her 15+ years of experience are related to using calculation and simulation tools to provide efficient chemical process solutions and consulting services in areas of mathematical modeling and process simulation, process design and optimization, advanced process control and operator training simulators. 

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