NATIONAL QUALIFICATIONS CURRICULUM SUPPORT


First published 1999
Electronic version 2001
© Scottish Consultative Council on the Curriculum 1999
This publication may be reproduced in whole or in part for educational purposes by educational establishments in Scotland provided that no profit accrues at any stage.
Acknowledgement
Learning and Teaching Scotland gratefully acknowledge this contribution to the
Higher Still support programme for Chemistry.
ISBN 1 85955 837 2
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Teachers’/lecturers’ guide
Background notes
Introduction
Major sectors of the chemical industry
Major products of the chemical industry
Chemical manufacturing
Chemical plant
Costs
Chemical manufacturing process
Preparation of feedstocks
The chemical reactor
Batch processing
Continuous processing
Product separation and purification
Energy
Chemical products
Safety and the environment
Questions
Bibliography
19
21
1
7
C H E M I S T R Y i i i

i v C H E M I S T R Y

T E A C H E R S ’ / L E C T U R E R S ’ G U I D E
This topic introduces Unit 3 but it could be taught later in the Unit as understanding will be enhanced by an awareness of chemical equilibrium. It is recommended that
3 – 4 hours should be allocated to cover the work. By its very nature the topic lacks practical work so it is essential that interest be maintained by providing a variety of activities. These could be based on the information provided in this booklet or on a variety of other resources available from the sources listed on page 21.
Certain Suggested Activities refer to finding out about ‘the steps in different processes’ and ‘the feedstocks in different processes’ and so on. Since these statements are not context specific it may be assumed that it is the concept of a stepwise process and the concept of a feedstock in relation to a process that should be constructed in the student’s mind rather than the detail of a particular process.
However, it is necessary to illustrate such concepts with examples, and so specific examples have been used in these notes but these examples do not form part of the formal Knowledge and Understanding requirement of the course.
In other cases the Suggested Activities refer to specific ideas such as finding out about
‘capital, fixed and variable costs’ in relation to manufacturing. Since these have specific meanings it is the expectation that these ideas would form part of the
Knowledge and Understanding requirement of the course.
The Background Notes in Section 2 of this pack contain all the basic information needed for the Content Statements.
Direct teaching can be used to impart some of the information in the topic but many of the Content Statements can be overtaken by information extraction exercises using a variety of resources.
C H E M I S T R Y 1

T E A C H E R S ’ / L E C T U R E R S ’ G U I D E
Many schools have links with local chemical companies and have organised school visits in the past. A visit to a local chemical plant is a good way of learning something about the industry at first hand. The success of such a visit is greatly enhanced if time is spent in explaining the structure and purpose of the visit to students prior to it taking place. In order to do this, a certain amount of preparatory liaison work between the company and the school is necessary. A company may have a standard format for a visit but it would be better if the school could try to tailor the visit as closely as possible to the needs of the students. It is no good organising an expensive visit if the students are unable to understand the chemistry of the processes involved when they get there. The advice of local authority Schools Industry Liaison Officers could also be sought.
However, it is important that students realise that one chemical plant is not representative of the entire chemical industry and that the industry makes a huge range of products. The information in these support notes can be used to illustrate this.
Compared to the UK chemical industry as a whole, Scotland is over represented in petrochemical plants and production plants for bulk chemicals and under represented in research and fine chemical manufacture.
Most of the Scottish chemical industry is situated in the central belt and therefore many schools are some distance from a suitable chemical plant. In addition, for one reason or another, many plants are unable to cope with school visits. Ensuring that students have access to a variety of resources – booklets, posters, videos, information technology – forms an acceptable alternative where a plant visit is not possible or not appropriate.
A list of sources of further information can be found on page 21. Each named contact issues a catalogue of available resources. Some are single companies and the information will relate to that company only. Since it is only the very biggest companies that can promote their own educational materials, others are umbrella bodies such as the Association of the British Pharmaceutical Industry.
2 C H E M I S T R Y

T E A C H E R S ’ / L E C T U R E R S ’ G U I D E
The Chemical Industry Education Centre at the University of York offers a wide range of useful materials and also offers an information service to schools. It publishes The
Essential Chemical Industry (see Bibliography and Resources data on page 21), which provides extensive information about the main products and processes of the chemical industry.
The Chemical Industries Association focuses more on support for its members but it does produce an inexpensive set of attractively illustrated booklets entitled Chemicals and the Quality of Life. The booklet titled Yesterday Today and Tomorrow provides a brief history of the chemical industry. Three other booklets cover the importance of chemicals to our lives, safety, and the environment. A fifth booklet describes how biotechnology can be used to help solve chemical problems, something that is worth highlighting. The information in these booklets is relevant to much of this topic.
Students could be given the task of finding relevant information in these booklets in order to prepare their own notes.
Salters Higher Chemistry (see Bibliography on page 21). Chapters 8, 9 and 23 are written specifically to cover all the content statements in the Arrangements for Higher
Chemistry. Much help was given by chemical companies to ensure the information is up-to-date and authoritative.
The Royal Society of Chemistry has issued a video plus teachers’ guide titled
Industrial Chemistry for Schools and Colleges . It is composed of 12 short sections each dealing with a particular manufacturing process, e.g. ammonia, copper, nylon.
The chemistry of each process is discussed, including aspects such as feedstock preparation. The materials could be used by students to find out about the feedstocks and raw materials that are used in different processes, about the steps in different processes, and about the different conditions needed. There are also accompanying worksheets. A set of industrial chemistry case studies and three workshop exercises on materials have also been issued. All of these are being distributed to all schools and colleges free of charge.
There are some websites on the Internet that provide information about the chemical industry. A new site is CITRUS, the Chemical Industry Teaching Resources User
Site, at http://www.jpleav.demon.co.uk. This site contains information about different chemical processes and students could use it to extract relevant information. Another site is being developed and will be opened in the summer of 1999; this is http://www.york.ac.uk/org/ciec and will be devoted to support for education by the chemical industry. This site is managed by the Chemical Industry Education Centre at the
C H E M I S T R Y 3

T E A C H E R S ’ / L E C T U R E R S ’ G U I D E
University of York. The Royal Society of Chemistry site at http://www.chemsoc.org/ is developing and growing all the time and resources may eventually be available from this source.
The Royal Society of Chemistry also organises Industry Study Tours which take place at a variety of sites across the UK. The National Centre for Education for Work and
Enterprise (based at the Jordanhill Campus of Strathclyde University) in association with the Royal Society of Chemistry organises Chemical Industry Workshops based at various locations in Scotland.
4 C H E M I S T R Y

B A C K G R O U N D N O T E S
The modern chemical industry is predominantly a 20th-century development. Modern life would be impossible without plastics, man-made fibres, pharmaceuticals and the thousands of other products made by the chemical industry.
The UK chemical industry is at the forefront of modern technology and is the nation’s fourth largest manufacturing industry . It is the fifth largest chemical industry in the world and the third ranking in Europe , behind Germany and
France. In 1996 its output was an estimated £36 billion .
The early chemical industry in Britain established itself in Scotland and the North of
England, close to deposits of its original raw materials: minerals, limestone, salt (i.e. sodium chloride), and coal. Gradually a communications infrastructure developed to transport its products to other areas and other countries, first by canal and ship, then rail, and then road. Due to good communication networks and the development of a pool of skilled labour the modern industry has maintained its links with its origins and most bulk chemical manufacture is still situated in Cheshire, Teeside, and Scotland.
Since the Second World War the UK chemical industry has made major capital investment in plant and has experienced a period of rapid expansion. As a result it is now both a major employer and a major contributor to the nation’s wealth. Five of the ten biggest companies in Britain are chemical companies . However, it is important to realise that the industry is very diverse and includes many small and medium sized companies as well.
In 1996 , the UK chemical industry had sales of £36 billion
. It is the UK manufacturing sector’s number one exporter : with exports of £22.9bn and imports of £18.5bn it earned a trade surplus of £4.4bn
. It provides direct employment for
250,000 people and supports several hundred thousand additional jobs throughout the economy.
Each job is backed by an investment of £250K of capital compared to a
C H E M I S T R Y 5

B A C K G R O U N D N O T E S
UK average of £84K making the industry a capital rather than labour intensive one . Despite having 9% of the UK population, Scotland only accounts for 6% of the chemical industry labour force. This is largely due to the fact that Scotland has more of the large, capital intensive production facilities and fewer of the labour intensive research and development facilities than the UK average.
Although the chemical industry provides employment for a large number of graduate and technician grade chemists it also employs large numbers of engineers – chemical, mechanical, civil, electrical. It also provides work for bioscientists, computer programmers, accountants, librarians, lawyers, transport workers and the many other types of employee to be found in any large organisation. The emphasis is very much on good training and on teamwork with each individual contributing according to his or her discipline.
Analysis of the UK chemical industry in terms of gross value added reveals the pattern in Figure 1 below.
Figure 1
O T H E R S
D Y E S T U F F S
IN O R G A N IC S
A G R O C H E MIC A L S
P A IN T S A N D IN K S
P L A S T IC S A N D R U B B E R S
S P E C IA L IT IE S
O R G A N IC S
T O IL E T R IE S
P H A R MA C E U T IC A L S
0 1 0 2 0
%
3 0 4 0
B R IT IS H C H E MIC A L IN D U S T R Y MA R K E T S H A R E B Y S E C T O R - 1 9 9 3
(Gross value added is a measure of the sales price less the cost of raw materials on a unit weight basis but takes sales volume into account also. A pharmaceutical will have a high GVA: although it sells in small quantities it may cost thousands of pounds per kilogram but will be made from starting materials which cost much less. Millions of
6 C H E M I S T R Y

B A C K G R O U N D N O T E S tonnes of polyethene are made each year but its GVA will be low because its price per kilogram will only be slightly higher than the ethene it is made from.)
It can be seen that pharmaceuticals is a highly profitable area. Other areas which add high value are toiletries, plastics, paints and agrochemicals (excluding fertilisers). The organics sector largely supplies the rest of the chemical industry with reagents and solvents since a large internal market is in operation. Specialities cover a wide range of chemicals such as flavourings and perfumery chemicals.
In order of tonnage produced (which can vary from year to year) the five most important chemicals are: sulphuric acid nitrogen oxygen ethene lime (calcium oxide)
The importance of sulphuric acid may be measured by the fact that the US chemical industry manufactured over 36 million metric tons of it in 1993. Much of the acid is used to make phosphate fertilisers, detergents, plastics and pigments , but it is also used in a large number of other chemical processes.
Large amounts of both nitrogen and oxygen are used in steel making . The manufacture of ammonia also uses significant amounts of nitrogen . Oxygen is used in many industrial processes where direct oxidation is involved, one example being the conversion of benzene to phenol via cumene (isopropylbenzene).
Ethene is the feedstock for many other petrochemicals and for polymers .
Lime has a number of industrial uses due to its basic nature but iron making accounts for about 45% of lime production. In the blast furnace the lime reacts with silicon dioxide in the iron ore to form slag.
C H E M I S T R Y 7

B A C K G R O U N D N O T E S
The chemical industry is not in existence to make chemicals: like any other industry it exists to create wealth and wealth can only be created if it can make profits. If a chemical company cannot sell its products at a profit then it goes out of business, either by closing or by being taken over. The economics of a chemical process are probably more important than its chemistry.
In order to look at chemical manufacturing more closely we need to distinguish between plant , process and product .
This is the term given to the equipment needed to carry out the process that will manufacture a product. Plants come in a variety of sizes and designs, and are usually designed around the manufacture of specific products. The trend is towards bigger and bigger plants in the hope that economies of scale will keep product prices competitive.
Just a few years ago, crackers that could produce 100,000 tons of ethene per annum were the norm: the most recently built crackers can produce in excess of half a million tons a year. The plant represents a massive financial investment and it is absolutely essential that a market has been correctly identified for the product at a price which will guarantee a return on the capital outlay. The plant will show a profit if product sales generated exceed costs over the lifetime of the plant.
Three types of cost are incurred in operating a chemical plant: capital costs, fixed costs, and variable costs .
Capital costs are incurred in the building of the plant and associated infrastructure.
Most companies would source the funding as a loan which would be paid back over the anticipated lifetime of the plant which, for depreciation purposes, is usually set at ten years. In fact many plants last longer than ten years but at some point they will have to be written off as obsolete and will need to be replaced.
Fixed costs are those which are incurred irrespective of whether a plant is operating at maximum capacity or only partial capacity. They include the costs of repaying the capital loan, rates, salaries, telephone costs etc .. The profitability of the plant therefore depends on keeping output as high as possible otherwise the income from sales will not cover these fixed costs. Increasing the product price is not an option due to the competitiveness of the market place.
Variable costs are determined by plant output. The most obvious examples are the cost of raw materials and the cost of distribution of the finished product . If production is low then little cost will be incurred in buying raw materials or distributing products.
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B A C K G R O U N D N O T E S
The process is the series of steps, sometimes referred to as unit operations, which turn raw materials into product. Nowadays chemical processes are highly automated and are operated under computer control from central control rooms staffed 24 hours a day.
In comparison with completely new products, completely new processes are a relatively rare occurrence. The cost of designing a new process is extremely high in terms of the research and development needed. The process must then be evaluated in a pilot plant which is a scaled down version of the full size plant. Finally the cost of a full scale plant must be borne. There must also be the certainty that the product can be manufactured at a lower price than is the case with existing processes. One recently introduced and very successful new process is the catalytic carbonylation of methanol to produce ethanoic acid , developed by Monsanto. The catalyst is rhodium based and the reaction is:
CH3OH + CO

CH3CO2H
This process uses lower temperatures and much lower pressures than its predecessors.
The licence to operate it is now owned by BP Chemicals.
C H E M I S T R Y 9

B A C K G R O U N D N O T E S
Figure 2 shows a flowsheet for a typical chemical process:
Figure 2 f r e s h f e e d s t o c k
MIXER r e c yc l e
R E AC T O R S E P AR A T O R p r o d u c t
The major raw materials of the chemical industry are fossil fuels, water, air, metal ores, and minerals such as limestone (calcium carbonate). Raw materials brought on site must first of all be prepared to convert them to feedstocks (i.e. reactants) before passing to the reactor where the chemical change takes place. The form this preparation takes will depend on the process and the reaction being carried out.
For example, the raw materials in the Haber Process for ammonia manufacture are methane, water (as steam), and air. The air must be filtered to remove any dust particles while the methane must pass through a desulphuriser to remove any impurities containing sulphur. These would poison the nickel catalyst used in the next stage of preparation which involves the reaction:
CH4 + H2O

CO + 3H2
Some of the CO reacts further with the steam:
CO + H2O

CO2 + H2
Air is then passed into the gas stream, adding nitrogen and converting most of the remaining CO to CO2 as shown (unbalanced):
N2 + O2 + CO + CO2 + H2

N2 + H2 + CO2
It is important to remove as much of the CO as possible since it poisons the iron catalyst used in the ammonia reactor.
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B A C K G R O U N D N O T E S
The carbon dioxide is removed by passing the gas mixture through potassium carbonate solution:
K2CO3 + H2O + CO2

2KHCO3
Heating the KHCO3 regenerates K2CO3. The CO2 produced is sold as a by-product, as a coolant for nuclear power stations, and to fizzy drink manufacturers.
Finally, the last traces of CO and CO2 are removed by converting them back into methane; the gas stream is adjusted to give a N2:H2 ratio of 1:3 and it then passes to the ammonia reactor.
The preparation process will often use more plant and be more time consuming and costly than the actual reaction process itself but, as far as the plant operator is concerned, proper preparation of raw materials is absolutely essential. If the preparation process failed then the results could be very costly: catalysts could be poisoned, yields could be reduced, products could be contaminated. It is more than likely that the plant would have to be shut down and then recommissioned, a very expensive business.
The chemical change takes place in the reactor which can have one of two different modes of operation: batch or continuous . The operation used depends on a number of factors.
Generally speaking, the batch type of reactor is used for the manufacture of relatively small amounts of chemical, up to about 100 metric tons per annum. They are not dedicated to the production of a single product but can be used to produce a number of different products. Plant based on batch reactors is less expensive to build than that based on continuous processing. Batch plants are usually used to manufacture high purity chemicals which are required in relatively small amounts. Examples are pharmaceuticals, dyestuffs and pesticides.
Batch reactors usually have a capacity of from 1 to 20 cubic metres. They are steel vessels and often have a glass or ceramic lining. They are equipped with a paddle
C H E M I S T R Y 1 1

B A C K G R O U N D N O T E S stirrer and coiled pipes through which either steam can be passed to bring reactants up to reaction temperature, or coolant to control exothermic reactions. The process is rather like a scaled up version of preparative organic chemistry. Once the reactants, usually in solution, have been allowed to react, the vessel is pumped out or drained off and the product is extracted by evaporation of the solvent which is recycled if possible. Batch reactors are useful when slow reactions have to be carried out since there are no constraints on the time needed to react. However, charging and emptying the reactor is both time consuming and costly since, compared to continuous processing, a larger workforce is needed. Reactor down time is also increased by the need to observe clean-out procedures at specified intervals, especially at product changeover times, when a reactor is to be used to manufacture a new substance.
Continuous processes are generally used to produce single products and operate around the clock, 365 days a year. They have the capacity to manufacture typically between 20,000 to 600,000 tonnes per annum and generally make key feedstocks which are turned into a wide range of products by ‘downstream processing’, i.e. further reactions. Most examples of continuous processing are to be found in the petrochemicals sector but ammonia is another well known example. Reactions are mainly conducted in the gas phase at high temperatures, often at high pressures, and extensive use is made of catalysts. The continuous reactor is basically a tube, usually packed with catalyst granules, and heated in some way. Feedstock gases flow in at one end and, since most reactions involve equilibria, product and unreacted feedstock gases flow out of the other.
The continuous process has some advantages over batch processing:
• it can be more easily automated and requires a much smaller workforce for the high tonnages produced;
• quality control of the product is more easily ensured;
• continuous operation makes for economic efficiency since shut-downs are months or even years apart.
Continuous processing also has some disadvantages compared to batch processing:
• the plant has higher capital costs than batch processing;
• it is less flexible since it is normally designed for a specific feedstock and product - an ethylene cracker cannot be used to make ammonia;
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B A C K G R O U N D N O T E S
• continuous process plants are not cost effective when operating below maximum capacity.
This stage depends very much on what is being produced and whether batch or continuous processing is involved.
Common separation processes involve flash evaporation, distillation, absorption, extraction, precipitation, and drying.
In the case of batch processes, the procedure is a scaled up version of laboratory practice. If the product is formed in solution, the batch reactor would be emptied, the solvent evaporated, and the product washed, dried and possibly further purified by crystallisation. Solvent systems are used which ensure high purity and high yield from crystallisation. If the product precipitates from solution, as in the case of an azo dye, it can simply be filtered off, washed and dried.
In the case of continuous processing it is usually a matter of isolating the product from the gas stream emerging from the reactor and recycling the unreacted feedstock. In the case of ammonia, the gas stream is chilled to –10 o
C and, under pressure, liquid ammonia condenses out at a temperature higher than its normal boiling point of
–33 o
C. Nitrogen and hydrogen remain in the gas state and are recycled back to the reactor. The ammonia is held under pressure, in the liquid state, for storage and transportation.
The air used in the Haber Process contains 1% argon and constantly recycling unreacted nitrogen and hydrogen leads to a build up of argon in the feedstock gas stream. At regular intervals, the recycled feedstock gas stream is drawn off and the argon can be removed by fractional distillation of the liquefied gases. The argon is then sold as a by-product.
Energy constitutes a major cost in any chemical process and, for that reason, every effort is made to keep energy costs down. Between 1990 and 1996 energy consumption in the industry fell although output rose, and energy efficiency improved by 14% over the period. Taking a longer perspective, on a pro-rata basis energy usage is only half what it was in the 1970s.
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B A C K G R O U N D N O T E S
The power plant is a most important part of any large chemical plant. The power plant produces steam for two purposes. The first is to drive turbines and generators. Large chemical plants normally generate their own electricity and have arrangements whereby they can sell any surplus to the national electricity distributors. The second is to provide the heat source for the chemical processes in the plant. Some processes may require temperatures that only a furnace can provide but most heating in a chemical plant is done by high pressure steam .
Steam is used because:
• it has a high latent heat content;
• it can be easily distributed;
• its flow is easily controlled;
• it is non-combustible and will not support combustion;
• it is non-toxic and relatively non-corrosive;
• it is produced from water which is cheap and abundant.
Steam is distributed around the plant in heavily lagged pipes so that as little energy as possible is lost.
In many continuous processes feedstocks have to be heated up to react, only for the products to be cooled down once the reaction is over. Heat exchangers are widely used to reduce significantly the amount of heat needed to heat up the feedstock.
Using heat exchangers, the heat produced in exothermic reactions can also be used productively. Shell and tube heat exchangers are the most common type and are designed to work with fluids, that is, liquids or gases. A simple heat exchanger of the
1 tube/1 shell type is shown in Figure 3.
Figure 3
4
2 1
3
The hot product gases from the reactor flow into the central tube at position 1 and the cool gases flow out at position 2. The cool feedstock flows into the shell at position 3 and the heated feedstock flows out at position 4. In this way, only a little extra heat is needed to bring the feedstock gases to reacting temperature. In practice, heat exchange
1 4 C H E M I S T R Y

B A C K G R O U N D N O T E S is maximised by passing the fluids through the exchanger more than once and by the fitting of internal baffle plates in the shell.
Another way in which the chemical industry has reduced energy costs has been by the development of new processes which require much lower temperatures than those they replace. The key element in this has been the development of new catalysts. For example, methanol is made by the following process:
CO + 2H2

CH3OH
The earlier zinc-chromium oxide catalysts required a temperature of about 400oC but the more modern copper based catalysts developed by ICI make it possible to carry out the process at about 250oC.
It is necessary to distinguish between manufacturing a completely novel product and one which is new to the company but may be made by other companies. In the latter case a company would purchase the process details, build the plant and go into production. In the former case, where perhaps a new pharmaceutical is to be manufactured, the story would be somewhat different.
The procedures for launching a new pharmaceutical on the market are rather different from most other new chemicals but the steps to production are similar and may be regarded as broadly typical. A new pharmaceutical will have its origins in the research lab. A promising compound showing the desired biological activity will first be patented. It will be tested on tissue and then on live animals using a set of protocols that are strictly adhered to. The substance will be needed in greater quantity by now and this will be manufactured in a pilot study by the product development group, using the route identified by research, but in kilogramme quantities. This group may also be making preliminary investigations into a synthetic route that could be used by a production plant. To reach this point may take about two years from initial discovery.
Any new pharmaceutical must undergo clinical trials which include detailed metabolic studies. Tolerance of different doses will be assessed along with an evaluation of different delivery systems – is the drug more effective as a syrup, a tablet, a capsule, or, as with anti-asthma treatments, an aerosol?
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B A C K G R O U N D N O T E S
Once a drug has passed the rigorous clinical trials it is given a licence and production can then proceed. Planning the scaling-up of production from small-scale laboratory experiments to full-scale operation will have been in progress since the final stages of the clinical trial period because it is important to get the product on sale as soon as possible. This is because a patent has a 20-year expiry date which commences as soon as the patent is registered, so the longer it takes to get the product to market the shorter is the period of patent protection. The average time it takes for pharmaceuticals from patent application to product launch is about 14 years. Although, naturally enough, the licensing procedure for pharmaceuticals is the most extensive, all new chemical substances in the public domain must accord with health and safety legislation in relation to the intended use of the product.
Production of a pharmaceutical will generally involve a multi stage synthetic route. At each stage the intermediate must be separated from the reaction mixture. Since contamination with unwanted by-products must be kept to a minimum the reaction route to the desired substance will probably be different from the original laboratory route. It will have been redesigned to minimise the number of reaction stages and to maximise the yield at each of those stages. A production route usually requires feedstock compounds which are not readily available. The normal practice is for pharmaceutical companies to buy these in from the many companies which specialise in bulk custom synthesis since this is more convenient than having to build dedicated plant. For example, the first step in the production of the anti-ulcer drug cimetidine
(Zantac) involves 2-cyanophenol and GlaxoWellcome buys this in bulk from a company in Alabama.
At all stages in the manufacture of a new product, the processes are reviewed and modifications are made, e.g. large and potentially dangerous temperature rises may be experienced during scaling up, necessitating adjustments to a process. The processes continue to be reviewed once the plant is in operation, e.g. looking for alternative approaches to the discharge of effluents.
Having a single supplier of an important feedstock is something that chemical companies usually try to avoid. If supplies are disrupted for any reason then the production process must close down. Having an alternative supplier will prevent this happening.
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B A C K G R O U N D N O T E S
The chemical industry operates thousands of potentially very hazardous processes, some involving highly toxic materials, others involving highly flammable materials at high pressures and temperatures, on sites with elevated work areas and moving machinery. Although the only acceptable accident rate is zero, it is testimony to good work practices that serious incidents are relatively rare. However, any disaster attracts media attention which in itself can distort the truth. The Flixborough disaster, which killed 28 people, is still used as a focus of criticism of the industry but it happened in
1974, a quarter of a century ago. Since that time safety standards have been tightened up considerably.
To place the industry in a proper context it is worth noting that accidents have decreased by 50% in the last decade and that the 1994 figure of 1.20 fatal and major injuries per thousand employees compares favourably with the figure of 1.25 for manufacturing industry in general. In fact, working in the chemical industry is 10 times less hazardous than deep sea fishing, and is 30% less hazardous than travelling by train!
Another aspect is the public perception of how safe the industry and its products are in relation to environmental pollution and to health. Despite the best efforts of the industry to promote its responsible attitude towards the environment, the public image remains poor. Certainly, when it comes to criticism, there is no shortage of ammunition: Rachel Carson’s Silent Spring drawing attention to the adverse effects of pesticides; Flixborough; Minamata Bay in Japan; Thalidomide; Seveso; Bhopal;
CFCs. It is a truism that only bad news sells newspapers but there can be no denying the involvement of the chemical industry in all of these. However, some were accidents caused by human error which can happen at any time in other sets of circumstances. Others were completely unintentional: DDT had immeasurably improved the lives of those living in malaria infested regions and the effects of DDT entering the food chain could not have been predicted at that time. In any case, the malaria problem was becoming acute and the solution was gratefully seized upon.
The outcome of these incidents has been a tightening up of environmental and other controls. For example, between 1990 and 1996, discharge of potentially harmful chemicals by the chemical industry into UK rivers was reduced by 91%. The UK chemical industry was not always so environmentally conscious and it has taken legislation to effect certain changes. There is growing public intolerance for those who damage the environment so every effort is being made to promote an image of an
C H E M I S T R Y 1 7

B A C K G R O U N D N O T E S industry which is well aware of its environmental responsibilities and is acting accordingly. Public education plays an important part in this and a great deal of effort is expended on schools – industry links of various kinds.
Chemical plants are designed with safety uppermost in mind. Sophisticated computer systems are used to monitor processes and will automatically shut down any part of the plant that is malfunctioning. Emissions from plants are kept to a minimum and air quality is constantly monitored. Warning systems are in place to alert local residents to any abnormal levels of emission.
Road and rail tankers used to carry chemicals are designed to withstand the hazards posed by the chemicals concerned. They are specially constructed to withstand impact in the event of an accident and are regularly inspected and tested. Tankers are also labelled with ‘Hazchem’ plates which give coded details of the chemical being carried, the hazards involved, and the procedures to be used in the event of a spillage. A contact telephone number for obtaining expert advice is also given.
Plants have their own fully equipped fire-fighting teams who are specially trained to tackle the specific types of fire that may occur in a plant. Being on site 24 hours a day means that they can reach the seat of a fire much more quickly than the local authority brigade and they will also have the specialist equipment needed to tackle it. In the event of a really serious emergency there will be a local disaster plan drawn up in cooperation with the local emergency services and health services. Regular exercises will be held to ensure that each participating service is familiar with its role in carrying out its part of the plan.
A mature view, surely, is to accept that attempts to improve the quality of life will always have their cost and acknowledge that it is unfortunate that the cost has to be borne so disproportionately. The judgement between cost and benefit is always a fine one. Returning to the squalor, disease, drudgery and malnourishment of the past is not an option. The price to be paid is ever greater vigilance to possible risks and an acceptance that the free environmental ride is over for good. While for many the term
‘chemical’ is a pejorative one, the products of the chemical industry pervade our lives in a way unimaginable to earlier generations and adjusting to an existence without them would be a painful process.
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Using resources made available to them, students could be asked to answer the following questions:
1. Prepare a brief list of the key events in the development of the chemical industry.
2. What are the major products of the chemical industry and what are they used for?
3. What are the major raw materials of the chemical industry? How does a raw material differ from a feedstock?
4. Explain why doubling the output of a chemical plant will double the variable costs but will not double the fixed costs and will not affect the capital costs .
(You will need to find out what the highlighted expressions mean before you can give your explanation.)
5. The UK chemical industry is capital intensive . What does this mean?
6. Chemicals can be made either by using a batch process or a continuous process . How are these different? Make a list of the advantages and disadvantages of each process.
7. Give three ways by which the chemical industry keeps energy costs down.
8. Give examples of how the chemical industry is becoming more aware of environmental issues.
9. Imagine a typical house. List the products of the chemical industry that are likely to be found in the house. Now list the natural materials likely to be found in the house.
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2 0 C H E M I S T R Y

Published sources of further information on the chemical industry:
Britain’s Chemical Industry, London: Foreign and Commonwealth Office, 1997
Burke, James, Connections, Boston: Little, Brown and Co, 1995
Emsley, John, The Consumer’s Good Chemical Guide, London: Corgi, 1996
Heaton, A., ed., An Introduction to Industrial Chemistry, Glasgow: Blackie Academic and Professional, 1996
Polymers : Chemical Industry Education Centre, University of York, 1994
Salters Higher Chemistry , Oxford: Heinemann, 1999
Salters Advanced Chemistry: Chemical Storylines, Oxford: Heinemann, 1994, 2nd edition 2000
The Essential Chemical Industry , Chemical Industry Education Centre, University of
York, 4th edition, 1999
Resource catalogues and other information about the chemical industry may be obtained from:
Chemical Industry Education Centre, Department of Chemistry, University of York,
York YO1 5DD
The Royal Society of Chemistry, Burlington House, Piccadilly, London W1V 0BN
The Chemical Industries Association, Kings Buildings, Smith Square, London
SW1P 3JJ
The Association of the British Pharmaceutical Industry, 12 Whitehall, London
SW1A 2DY
BP Education Services, 99 Holderhurst Road, Bournemouth BH8 8EE
Shell Education Service, PO Box 46, Newbury, Berks RG13 2YX
Jane Gamble, Education Manager, Room D219, Wilton Centre, PO Box 90, Wilton,
Middlesborough TS90 8JE (ICI contact)
Anil Kumar, Education Manager, GlaxoWellcome, Medical ResourceCentre,
Gunnells Wood Road, Stevenage SG1 2NY
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