3.6 Industrial Processes

A continuous process is a non-stop process where products are removed at the same time as new reactants are added

A batch process is an intermittent process where reactants are added, a reaction occurs and the product is removed. The vessel is then cleaned and the process is started again with new reactants.

• Fast production rate • can be automated • low labour costs • can be used to produce large amounts of the chemical/ suitable for large scale production

• higher set up cost • complex technology • its specific for one product or chemical

• low set up/ capital costs -Not specific to one chemical or product • simpler technology

• less automated so higher labour costs -Slower reaction time

• The Haber process to manufacture ammonia -Fractional distillation of crude oil • fertiliser manufacture

Capital cost is the cost of setting up a business or plant

• Construction of the plant • Plant equipment • Storage for raw materials and products -Design fees

Indirect cost means that the cost per unit of product is not directly proportional to this cost. Indirect costs stay the same at all levels of output and are related to maintenance, research and office work

• Insurance of the plant • Rent of the plant • Sales and marketing costs • Labour / wages • Maintenance of the plant • Research and development

Direct cost means the cost per unit of the product is directly proportional to this cost. Direct costs are ongoing costs to run the process. If the manufacturer doesn’t produce anything then the direct costs are zero

• Fuel • Electricity • Raw materials ( reactants and catalysts) • Packaging • Transport

• Generates money for the local economy, as commuting employees bring trade to local shops and businesses • improves infrastructure and services, as good transport links (roads and rail) and services ( water, gas, electricity and internet) are needed for the plant • Creates employment opportunities for specialist staff ( like scientists, researhcers and engineers) and support staff ( like clerical, canteen and security staff)

• Environmental Consequences • Infrastructure • Waste management

• Air pollution - as chemical plants emit harmful waste gases such as sulfur dioxide which causes acid rain and respiratory problems for animals and humans • Water pollution - chemical plants can discharge hot water, resulting in thermal pollution ( which reduces the dissolved oxygen content of lakes and rivers causing eutrophication) • Noise pollution - Chemical plants emit noise from the vehicles used to transport both raw materials and finished product, and from the machinery uses to manufacture the chemicals • Depletion of resources - many raw materials are taken from the earth, air and water so finite resources are removed

• Must be close to good road and rail links for transport of raw materials and distribution of the finished product • Must be close to a town or population to provide workers for the plant • It may need to be close to a source of the bulk raw material(s), as this will reduce transport costs

• Sufficient drainage and water treatment for the plant • Measures to control air pollution • Hazards regulations and safety factors to cope with major accident or chemical spillages • measures to store and dispose of hazardous waste

In laboratory preparation : - small quantities of chemicals are used so cost is not a big issue - most of the chemicals used are readily available In industrial production: - Larger quantities of materials are needed so the cost will limit the choice of material used - There may be a limited choice of chemicals, as some are not available in large amounts

Laboratory- scale: - Normal laboratory conditions are used - no extreme temperatures or pressures - Normal-sized reaction vessels are used Industrial-scale: - Higher temperatures and pressures are possible using specialised equipment. Sensors are included to monitor the temperatures and pressures - Large specially designed reaction vessels are used. That often have automated stirrers and pipework to transfer the materials - Heating and cooling systems are often part of the equipment

Laboratory-scale: - The small quantities of chemicals are easily disposed of Industrial-scale: - Larger quantities pose a disposal problem, especially if the waste is harmful

• Apparatus • Transfer of materials • Energy costs • Formation and disposal of side products • Disposal of effluent (liquid waste) • Heating and cooling