Clean Technology for the Manufacture of Speciality Chemicals

By W. Hoyle, M. Lancaster

The Royal Society of Chemistry

Copyright © 2001 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-0-85404-885-4

Contents

Clean Technology for Speciality Chemicals Mike Lancaster, 1,
Clean Technologies to Meet Economic, Environmental and Safety Needs D. S. Ridley, 6,
The Clean Technology Route to Waste Minimisation Adrian J. Cole, 13,
How Green Is My Process? A Practical Guide to Green Metrics Paul Smith, 24,
Process Intensification: Potential Impact on the Chemical Industry C. Ramshaw, 32,
Process Intensification: Choosing the Right Tools C. de Weerd, 37,
Sulphones by Oxidation – the Development Perspective David A. Jackson, Howard Rawlinson and Oskar Barba, 47,
New Catalysts for Old Reactions D. C. Braddock, A. G. M. Barrett, D. Ramprasad and F. J. Waller, 54,
Catalysis for Fine Chemicals: An Industrial Perspective Pascal Mdtivier, 68,
A Case Study on Recovery and Reuse of Complex Solvent Mixtures from Chemical Production Ted Lee, 78,
Subject Index, 92,

CHAPTER 1

CLEAN TECHNOLOGY FOR SPECIALITY CHEMICALS

Mike Lancaster

Manager Green Chemistry Network
Department of Chemistry
University of York
York YOIO SDD

1 INTRODUCTION

The concepts of clean technology and green chemistry have been around for 10 years or so and slowly but surely these ideas are gaining acceptance by a wider cross section of industry. One of the main obstacles to progress is the mistaken belief that clean technology, which is designed to limit pollution and environmental damage, equates to a reduction in bottom line profitability. Can a modern speciality chemical business can be successfully run on the principles of the Triple Bottom Line and are Clean Technology and increased profitability happy bedfellows? This is a question many people are starting to ask, and as the papers in this book will demonstrate the answer is a resounding yes.

So what is Clean Technology or Green Chemistry all about? First and foremost it is about reducing waste. Waste is increasingly expensive to dispose of and the major source of pollution coming from the chemical industry. Maximising atom efficiency is linked to waste reduction. The concept of designing chemical reactions such that as many atoms of starting material as possible end up in useful product may seem common sense but sadly is not often followed. Secondly it is about reducing materials, this includes raw materials, and materials of construction; this area brings in the concepts of process intensification which will be fully discussed in later chapters.

Clean technology is also about reducing the hazard and the risk both to people and the environment; this brings in concepts such as inherently safe design of reactions and substitution of hazardous chemicals or those that pose a high risk. In short green chemistry is about reducing the environmental impact of both processes and products.

One important aspect of green chemistry, which is often forgotten, is cost. If industry is to take up these wonderful ideals of green chemistry it will only do so if it makes economic sense. However if we have reduced waste, materials, energy etc. then it is also very likely that the cost has also been reduced (Figure 1).

From the above description it should be evident that Clean technology involves both chemistry and chemical engineering. If industry is to develop the cleaner processes now being demanded we need to establish multidisciplinary teams at the conceptual stage.

Industry need not look on environmental protection as an additional burden imposed by Governments and society it should look at it as an additional opportunity to develop more cost effective processes and products. With a little thought, and perhaps a culture change, the chemical industry can be competitive and environmentally benign.

UK chemical industry expenditure on environmental technology during 1997 was almost a quarter of that spent by UK industry as a whole. Expenditure is divided into 3 – by far the largest is operating expenditure some 65% of the total of over £1,000 million. The rest is capex: some 26% was spent on end of pipe technology with only 9% being spent on what might be considered integrated process clean technology.

Spending on environmental technology almost doubled between 1994 and 1997. It is little wonder that looking at these figures that industry believes that protecting the environment is adding to its un-competitiveness, since the figure spent is over 5% of revenue generated by sales. However I would like to present these figures as an opportunity rather than a threat to the industry. Only £100 million pounds is currently spent on what I would consider the most valuable area of clean technology. The real opportunity lies in increasing this expenditure by a factor of 2 or 3 and eliminating a significant part of this end of pipe and operating costs (Figure 2).

The root cause of this vast sum spent on environmental technology is waste, and as Sheldon has pointed out it is the fine, speciality and pharmaceutical sectors which have more of a problem with waste (on a Kg per Kg product basis) than the bulk chemicals industry. Looking closely at the cost of waste within the speciality chemicals sector is a little more difficult. For many smaller companies working with multipurpose plants the true breakdown of manufacturing costs is still often unknown – overheads can be used to hide a multitude of sins! With the rapid development in sophisticated process monitoring equipment and state of the art control systems the true production cost is slowly becoming evident. The most important information coming out of this analysis is that the cost of waste, (including effluent treatment, waste disposal, loss of raw materials etc.) often amounts to some 40% of the overall production costs (Figure 3).

So what are the technologies that are being used or are likely to be used in the near future to both drive down costs and create more environmentally friendly processes? The bulk chemicals industry has been transformed by the increased use of catalysis

Today there are around 130 chemical manufacturing processes such as alkylation, isomerisation, amination and etherification using catalysts such as zeolites, ion exchange resins, clays and complex oxides. This technology has largely been developed to maintain competitiveness, improve product quality, and improve process efficiency. For example the waste produced from the very large scale use of aluminium chloride in alkylation reactions started to make the process uneconomic. Introduction of zeolites and other heterogeneous catalysts has had both significant cost and environmental benefits. It is untrue to say that catalysts are not used in the speciality chemicals industry but their use is not as widespread as it could be. Potential cost benefits result from faster processes, higher selectivities and lower energy use (Figure 4).

Supercritical fluid technology has been around for many years but, largely due to the relatively high pressures involved, remained a laboratory curiosity. Supercritical carbon dioxide is commercially used for extraction processes and the technology is now being looked at seriously for chemicals manufacture. The reasons for this are that improvements in engineering mean that the equipment is more affordable and when combined with modem catalyst technology the rates of some reactions are very fast. Hence for true low volume specialities there is the potential for producing requirements from a small relatively low cost plant. Companies such as Thomas Swan and Hoffman La Roche are now looking to commercialise the technology for reactions like continuous hydrogenation and alkylation. It is not a universal answer but is likely to provide true competitive advantage in a niche market.

Ionic liquids are another emerging technology which may avoid the use of organic solvents. Although these materials are strong acids and may not be particularly environmentally friendly in their own right they can be readily recycled due to their immiscibility with most organics. They are being studied particularly for reactions which require highly acidic conditions such as alkylation where they act as both a solvent and a catalyst.

Process intensification is one of the chemical engineering solutions to clean technology. The main benefits are often lower energy uses, lower capital costs and increased throughput from a smaller plant derived from different engineering conceptual designs. The next generation of plants will be smaller, cheaper, and more environmentally friendly to run.

As the energy intensity of a process becomes more of an issue on cost and environmental grounds we shall start to see processes being developed using microwave, ultrasonic, electrochemical and photochemical reactors. For some reactions these techniques will not only deliver energy efficiency but may also lead to higher selectivities and atom efficiencies.

Environmental concerns are here to stay. They can be viewed as a threat requiring ever increasing expenditure on end of pipe technologies to meet ever-increasing legislation or they can be viewed as an opportunity to introduce cleaner processes, which are more efficient and cost effective.

CHAPTER 2

CLEAN TECHNOLOGIES TO MEET ECONOMIC, ENVIRONMENTAL AND SAFETY NEEDS

D. S. Ridley

Environment Agency
Coverdale House, Aviator Court
Amy Johnson House, Amy Johnson Way
Clifton Moor
York Y030 4GZ

1 INTRODUCTION

The objective of this paper is to consider the pressures on today’s industry, to identify the commonality between these pressures and to identify the solutions for the future. Examples will be used to illustrate that to succeed in the future our thinking and approach towards science and technology will have to be radically different to that of today.

The first question to be asked before considering the role of the chemical industry in the future is to question its need. The world’s population continues to increase from today’s all time maximum. The life expectancy of both the fit and the ill in the developed world continues to increase. Our response to natural disasters or problems threatening life anywhere around the world invariably involves the deployment of the products of the worlds chemical industry. The developing world progresses into the developed world by acquiring or producing amongst other products the products of the chemical industry.

Quality of life is a complex and controversial parameter to define. Suffice to say that the majority of definitions of improvement in a quality of life directly or indirectly refer to the availability or use of the products of the Chemical Industry. It is inconceivable that our current quality of life let alone that of the future could be sustained without a viable chemical industry. The above analysis should not be interpreted as inferring that the industry has some form of divine right to its existence, in order to be viable the chemical industry needs to constantly adapt and change to meet the needs of society.

Looking ahead to what will be important for the industry in the future, emphasis is likely to be placed on the following aspects:-

• Product quality and efficacy

• Competitive price

• Return on investment

• Exciting place to work

• Being heard but not seen

What is proposed as important in the future is no different to what will be construed by many as being important today. What may surprise is the likely extent and potential pace of the necessary changes. The pace of change is likely to be set by the rate of development of the already developing eastern economies. In the main these economies are well endowed with creative technical expertise and as they expand they are installing technology at least the match of our own.

2 PRODUCT QUALITY AND EFFICACY

Product quality and efficacy improvements are likely to be driven more from the litigation based developed nations, than by eastern competition, at least in the short-term. In the fine chemical industry the need to produce and isolate only the precise isomer of the active molecule is likely to increase i.e. we need to make the exact molecule we want. Whilst new chemistry, new catalysts and new extractive routes will all play their part so also will the need to precisely define and control the reactions and extractions at a level not currently available and in many instances not yet dreamed of. In the polymer industries, in common with other performance or property products, the ability to produce the specific product for the specific purpose will provide the more lucrative markets.

In short meeting the individual customers individual needs, whilst possibly assisting the customer to identify and specify their specific need is likely to provide the more lucrative and sustainable markets. Not only does this raise the spectre of new or much refined existing technologies it also questions the economic scale of a future plant. Does the engineering need to be developed to ensure that a plant sized to provide a customer’s precise needs is economic rather than having to scale a plant to serve the entire markets need before it can be judged to be economic.

3 COMPETITIVE PRICE

The premium payment for supplying a customised or specific product to a customer to allow them to optimise or customise their product should continue. Additionally the concept of sustainability is beginning to take root. Questions at annual general meetings are beginning to include pertinent questions relating to the environmental footprint and the social conscience of the organisation its suppliers and contractors. The Chemical industry is possibly disproportionately blamed for its perceived environmental impact. All companies express their economic performance as a series of factors all expressed in or easily convertible into US Dollars. Surely we need to develop and agree, with our stakeholders, the methods and means by which we can calculate an organisations environmental and social balance sheet in order to confirm and reply to or alternatively deny the charges levelled at almost all organisations within or related to the chemical industry. An example of such an environmental tool is given later.

4 RETURN ON INVESTMENT

In the recent past the capital value of the physical plant normally dominated the balance sheet. Today a number of companies have to include a greater provision to cover the potential costs of remedying problems or liabilities, associated with the plant such as land contamination or problems associated with either the use or abuse of the product or by-products. Whilst in certain well-publicised cases these costs are indeed very substantial, many other companies are blighted by the possibility of the costs. Much modern regulation, such as Control of Major Accident Hazards (COMAH), Integrated Pollution Prevention and Control (IPPC), Integrated Pollution Control (IPC) and much of the waste legislation are rightly more about liability management and minimisation than about direct impact. Whilst I acknowledge that a banker or insurer’s greatest hate is an unquantifiable risk and that the greatest joy of a prosecuting lawyer is to use a risk assessment as proof of the company’s willingness to take risks. I believe that the majority, including a presiding judge, realise that progress is only made through the management of risk which has at its core ‘do the benefits outweigh the dangers’. In view of this the ‘applications for permitting’ under the above legislation should not only assess and quantify the risks of the process or product but should also quantify the benefits. To do this in an uncontentious manner will require the development of a new system of benefit assessment, yet another new tool for the future.

The minimisation of capital has exercised the minds of every generation of engineers, so what is new today. In spite of several years of low and relatively predictable inflation and interest rates the financial markets expectation is often for double figure growth at minimum capital investment. The hapless Chemical Company finance director seeking several hundreds of millions of pounds over 20 years is unlikely to excite the market.

The availability of grants has influenced the spectrum of investment decisions over recent decades. It is important to recognise that the European support systems are likely to focus more on rebuilding the industrial infrastructure of the new eastern member or applicant states than on that of the more established economies.

5 EXCITING PLACE TO WORK

The success of the industry is not only dependent upon the supply of sufficient trained staff to design, build, operate and maintain the process, but upon an adequate supply of these trained individuals into all the associated businesses needed to support the primary business. These businesses include banking, insurance, regulation and the media. Without individuals in these associated businesses with a comprehension of the technologies, the risks and benefits of the processes a balanced representation of the viability, risks and benefits offered by a specific proposal or plant will be so much harder to gain.

As a result of the above it is essential to retain a greater number of students beyond GCSE than is currently being achieved. To do this some curricula for the study of sciences, engineering and chemistry in particular may need rejuvenating to make them more dynamic and pertinent to modern life.

6 BE HEARD BUT NOT SEEN

The chemical industry is frequently portrayed in a rather negative manner. Many individuals can not relate the medicine they are taking, the fabric they are wearing, the abundant clean food they are consuming or the cleaner fuel they are using to the chemical industry. In the more extreme situations the plant passed on the way to work is a place of mystery and suspicion. With few cars in the car park and protected by an aggressive fence all that is produced is the occasional bad smells or noise. No useful product emerges. The positive initiatives taken by the industry or the leading edge techniques used to assess issues such as risk are not sufficiently publicised or pushed. These associations are necessary if we are to begin to change the extreme but not unrealistically negative image of the industry outlined above. Increasingly industry is responding to societies demand for zero emissions, no hazards and no accidents through initiatives such as responsible care, cradle to grave responsibility and risk and liability management.

7 THE CHEMISTRY OF THE FUTURE

The above is something of a wish list for a competitive, hazard and pollution free chemical industry but the question is can this be achieved with current technology in a standard 500 gallon glass lined stirred reactor? The answer is surely no, chemistry of the future will require:

• Intense controlled reaction conditions

• Intense controlled energy transfer

• Precise and rapid control of all relevant reaction parameters

(Continues…)Excerpted from Clean Technology for the Manufacture of Speciality Chemicals by W. Hoyle, M. Lancaster. Copyright © 2001 The Royal Society of Chemistry. Excerpted by permission of The Royal Society of Chemistry.
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