Embed Size (px)
Citation preview
PLANT DESIGN SKKK 4153
SYED ANUAR FAUA’AD B. SYED MUHAMMAD Dept. of Bioprocess and Polymer Engineering,
Faculty of Chemical Engineering. N01a-24
Notes contributor: Dr. Zarina Muis/Dr. Agus/Dr. Abbas
Intro to PD - 2
Learning Outcomes
After studying this topic, participants should:
• Be able to recognize suitable site for a new project, and the site and equipment layout planned. Provision must be made for the ancillary buildings and services needed for plant operation; and for the environmentally acceptable disposal of effluent.
Chemical Process
Industry
Chemical Process Industry Disaster
Intro to PD - 5
1. Location, with respect to the marketing area. 2. Raw material supply. 3. Transport facilities. 4. Availability of labor. 5. Availability of utilities: water, fuel, power. 6. Availability of suitable land. 7. Environmental impact, and effluent disposal. 8. Local community considerations. 9. Climate. 10. Political and strategic considerations.
PLANT LOCATION AND SITE SELECTION
Intro to PD - 6
Marketing area
Materials in bulk quantities eg. cement, mineral acids, & fertilisers, where: 1. the cost of the product per tons is relatively low and 2. the cost of transport a significant fraction of the sales price, the plant should be located close to the primary market. This consideration will be less important for low volume production, high-priced products; such as pharmaceuticals products.
Raw Materials
• Site location Depends on availability and price of suitable raw materials
• Plants that produce bulk chemicals are best located close to the source of the major raw material, as long as the costs of shipping product are not greater than the cost of shipping feed.
Raw Materials
• Eg. new ethylene capacity that is being added worldwide is being built in the Middle East, close to supplies of cheap ethane from natural gas (NG).
• Oil refineries, on the other hand, tend to be located close to major population centers, as an oil refinery produces many grades of fuel, which are expensive to ship separately.
Transport
• If practicable, a site should be selected that is close to at least two major forms of transport: road, rail, waterway (canal or river), or a sea port.
• Road transport is increasingly used and is suitable for local distribution from a central warehouse.
• Rail transport is usually cheaper for the long-distance transport of bulk chemicals.
• Air transport is convenient and efficient for the movement of personnel & essential equipment and supplies, and the proximity of the site to a major airport should be considered.
Intro to PD - 10
Availability of Labor
• Labor for construction of the plant and its operation.
• Skilled construction workers are usually brought in from outside the site area, but there should be an adequate pool of unskilled labor available locally, & labor suitable for training to operate the plant.
Intro to PD - 11
Availability of Labor
• Skilled craft workers such as electricians, welders, and pipe fitters will be needed for plant maintenance.
• Local labor laws, trade union customs, and restrictive practices must be considered when assessing the availability & suitability of the local labor for recruitment and training.
Intro to PD - 12
Utilities (Services)
• Chemical processes invariably require large quantities of water for cooling & general process use, & the plant must be located near a source of water of suitable quality.
• Process water may be drawn from a clean river, wells, or purchased from a local authority.
• At some sites, the cooling water required can be taken from a river, lake, or from the sea; at other locations cooling towers will be needed.
Utilities (Services)
• Electrical power is needed at all sites. Electrochemical processes (eg. chlorine manufacture or aluminums/metal melting) require large quantities of power & must be located close to a cheap source of power.
• A competitively priced fuel/NG must be available on site for steam and power generation.
Environmental Impact & Effluent Disposal
• Full consideration must be given to the difficulties & cost of industrial disposal.
• The disposal of toxic and harmful effluents will be covered by local regulations, & the appropriate authorities must be consulted during the initial site survey to determine the standards that must be met.
• An environmental impact assessment should be made for each new project or major modification or addition to an existing process.
Local Community Consideration
• The proposed plant must fit in with & be acceptable to the local community.
• Safe location of the plant, so that it does not impose a significant additional risk to the local population.
• Plants should generally be located in the area so as not to be upwind/windy of residential areas.
Local Community Consideration
• Local community must be able to provide adequate facilities for the plant personnel: schools, banks, housing, and recreational and cultural facilities.
• The local community must also be consulted about plant water consumption & discharge & the effect of the plant on local traffic.
Intro to PD - 17
Local Community Consideration
• Some communities welcome new plant construction as a source of new jobs and economic prosperity.
• However, more affluent/wealthy communities generally do less to encourage the building of new manufacturing plants & in some cases may actively discourage chemical plant construction.
Land (Site Consideration)
• Sufficient suitable land must be available for the proposed plant and for future expansion.
• The land should ideally be flat, well drained, and have suitable load-bearing characteristics.
• A full site evaluation should be made to determine the need for piling or other special foundations.
Land (Site Consideration)
• Particular care must be taken when building plants on reclaimed land near the ocean, and in earthquake zones because of the poor seismic/less stable character of such land.
Climate
• Adverse climatic conditions at a site will increase costs.
• Abnormally low temperatures require the provision of additional insulation and special heating for equipment & pipe runs.
• Stronger structures are needed at locations subject to high winds (cyclone/hurricane areas) or earthquakes.
Intro to PD - 21
Political & Strategic Considerations
• Capital grants, tax concessions/reductions, and other incentives are often given by governments to direct new investment to preferred locations, such as areas of high unemployment.
• The availability of such grants can be the overriding/dominant consideration in site selection.
• In a globalized economy, there may be an advantage to be gained by locating the plant within an area with preferential/special tariff agreements, such as the European Union (EU).
Intro to PD - 22
• The process units and ancillary buildings should be laid out to give the most economical flow of materials and personnel around the site.
• Hazardous processes must be located at a safe distance from other buildings.
• Consideration must also be given to the future expansion of the site.
SITE LAYOUT
Intro to PD - 23
The ancillary/secondary buildings and services required on a site, in addition to the main processing units (buildings), include:
1. Storage for raw materials and products: tank farms and warehouses;
2. Maintenance workshops;
3. Stores, for maintenance and operating supplies;
4. Laboratories for process quality control;
5. Fire stations and other emergency services;
6. Utilities: steam boilers, compressed air, power generation, refrigeration, transformer stations;
SITE LAYOUT
7. Effluent disposal plant: waste water treatment, solid and or liquid waste collection;
8. Offices for general administration;
9. Canteens and other amenity buildings, such as medical centers;
10. Parking lots.
SITE LAYOUT
Intro to PD - 25
• The process units are normally sited first and arranged to give a smooth flow of materials through the various processing steps, from raw material to final product storage.
• Process units are normally spaced at least 30 m apart from others utilities/buildings; greater spacing may be needed for hazardous processes.
• Next, decide the location of the principal ancillary buildings.
• They should be arranged so as to minimize the time spent by personnel in traveling between buildings.
SITE LAYOUT
• Administration offices and laboratories, in which a relatively large number of people will be working, should be located well away from potentially hazardous processes.
• Control rooms are normally located nearby to the processing units, but those with potentially hazardous processes may have to be sited at a safer distance.
• The location of the main process units determines the layout of the plant roads, pipe, alleys, and drains.
• Access roads to each building are needed for construction and for operation and maintenance.
SITE LAYOUT
• Utility buildings should be sited to give the most economical run of pipes to & from the process units.
• Cooling towers should be sited so that, under the prevailing wind, the plume of condensate spray drifts away from the plant area and adjacent properties.
• The main storage areas should be placed between the loading and unloading facilities and the process units they serve.
• Storage tanks containing hazardous materials should be sited at least 70 m (200 ft) from the site boundary.
SITE LAYOUT
SITE LAYOUT : A typical site plan
Intro to PD - 29
• The economic construction and efficient operation of a process unit will depend on how well the plant and equipment specified on the process flowsheet is laid out.
• The principal factors to be considered are
1. Economic considerations: construction and operating costs;
2. The process requirements;
3. Convenience of operation;
4. Convenience of maintenance;
5. Safety;
6. Future expansion;
7. Modular/Flexible/Integrated construction.
PLANT LAYOUT
Cost
• The cost of construction can be minimized by adopting a layout that gives the shortest run of connecting pipe between equipment and the least amount of structural steel work;
• However, this will not necessarily be the best arrangement for operation & maintenance.
Process Requirements
• An example of the need to take into account process considerations is the need to elevate the base of columns to provide the necessary net positive suction head to a pump (see Chapter 5, Sinnot) or the operating head for a thermosiphon reboiler (see Chapter 12, Sinnot).
Intro to PD - 32
Operation
• Equipment that needs to have frequent operator attention should be located convenient to the control room.
• Valves, sample points, and instruments should be located at convenient positions and heights.
• Sufficient working space and headroom must be provided to allow easy access to equipment. If it is anticipated that equipment will need replacement, then sufficient space must be allowed to permit access for lifting equipment.
Intro to PD - 33
Maintenance
• Heat exchangers need to be sited so that the tube bundles can be easily withdrawn for cleaning and tube replacement.
• Vessels/Reators that require frequent replacement of catalyst or packing should be located on the outside of buildings.
• Equipment that requires dismantling for maintenance, such as compressors and large pumps, should be placed under cover/shades.
Safety
• Blast walls may be needed to isolate potentially hazardous equipment and confine/scure the effects of an explosion.
• At least two escape routes for operators must be provided from each level in process buildings.
Plant Expansion
• Equipment should be located so that it can be conveniently tied in/fitted with any future expansion of the process.
• Space should be left on pipe racks for future needs, and service pipes should be oversized to allow for future requirements for new fittings.
Intro to PD - 36
Modular Construction
• In recent years there has been a move to assemble sections of a plant at the plant manufacturer’s site.
• These modules include the equipment, structural steel, piping, and instrumentation.
• The modules/quipments are then transported to the plant site, by road or sea.
Intro to PD - 37
Modular Construction
• The advantages of modular construction are
1. Improved quality control;
2. Reduced construction cost;
3. Less need for skilled labor on site;
4. Less need for skilled personnel on overseas sites.
Modular Construction
• Some of the disadvantages are:
1. Higher design costs;
2. More structural steel work;
3. More flanged connections;
4. Possible problems with assembly, on site;
Intro to PD - 39
General Consideration
• Open, structural-steelwork buildings are normally used for process equipment (good for ventilations and heat release).
• Closed buildings are used for process operations that require protection from the weather, for small plants, or for processes that require ventilation with scrubbing of the vent gas.
• The arrangement of the major items of equipment often follows the sequence given on the process flowsheet: with the columns and vessels arranged in rows & the ancillary equipment, such as heat exchangers and pumps, positioned along the outside.
Intro to PD - 40
General Consideration
• A typical preliminary layout for major and ancillary equipment.
Intro to PD - 41
Techniques Used in Site and Plant Layout
• Cardboard cutouts of the equipment outlines can be used to make trial plant layouts.
• Simple models, made up from rectangular and cylindrical blocks, can be used to study alternative layouts in plan and elevation.
• Cutouts and simple block models can also be used for site layout studies.
• Once the layout of the major pieces of equipment has been decided, the plan and elevation drawings can be made and the design of the structural steelwork and foundations undertaken.
Techniques Used in Site and Plant Layout
• Large-scale models, to a scale of at least 1:30, are normally made for major projects.
• These models are used for piping design and to decide the detailed arrangement of small items of equipment, such as valves, instruments, and sample points.
• Piping isometric diagrams are taken from the finished models.
• The models are also useful on the construction site and for operator training. Proprietary kits of parts are available for the construction of plant models.
Intro to PD - 43
Techniques Used in Site and Plant Layout
• Computer-aided design (CAD) tools are being increasingly used for plant layout studies, and computer models are complementing, if not yet replacing, physical models.
• Several proprietary/exclusive programs are available for the generation of three-dimensional models of plant layout and piping.
• Present systems allow designers to zoom in on a section of a plant and view it from various angles.
• Developments of computer technology will soon enable engineers to virtually walk through the plant.
Intro to PD - 44
Techniques Used in Site and Plant Layout A typical computer-
generated model
Intro to PD - 45
Techniques Used in Site and Plant Layout
• Some of the advantages of computer graphics modeling compared with actual scale models are:
1. The ease of electronic transfer of information. Piping drawings can be generated directly from the layout model. Bills of quantities: materials, valves, instruments, etc. are generated automatically.
2. The computer model can be part of an integrated project information system, covering all aspects of the project from conception to operation.
3. It is easy to detect interference between pipe runs and, pipes and structural steel that occupy the same space.
Intro to PD - 46
Techniques Used in Site and Plant Layout
4. A physical model of a major plant construction can occupy several square meters. The computer model is contained on a single CD.
5. The physical model has to be transported to the plant site for use in the plant construction and operator training. A computer model can be instantly available in the design office, the customer’s offices, and at the plant site.
6. Expert systems and optimization programs can be incorporated in the package to assist the designer to find the best practical layout.
1. Electricity;
2. Steam, for process heating;
3. Cooling water;
4. Water for general use;
5. Demineralized water;
6. Compressed air;
7. Inert-gas supplies;
8. Refrigeration;
9. Effluent disposal facilities.
UTILIIES
Intro to PD - 48
Waste Management
Wastes
Gaseous
Liquid Solid
Aqueous
Intro to PD - 49
1. All emissions to land, air, and water;
2. Waste management;
3. Smells;
4. Noise;
5. Visual impact;
6. Any other nuisances;
7. The environmental friendliness of the products.
ENVIRONMENTAL CONSIDERATIONS
Environmental Legislation
• Environmental Quality Act 1974 An Act relating to the prevention, abatement/reduce, control of pollution and enhancement of the environment, and for purposes connected therewith.
Intro to PD - 51
Elements Covered Under EQA 1974
EQA 1974
Air
Water Noise
Industrial Waste
Intro to PD - 52
Examples of Regulations Under EQA 1974
Environmental Quality (Licensing) Regulations 1977
Environmental Quality (Control of Emissions from Petrol Engines Regulations 1996
Environmental Quality (Delegation of Powers) (Investigation of Open Burning) Order 2000
Environmental Quality (Declared Activities) (Open Burning) Order 2003
Environmental Quality (Appeal Board) Regulations 2003
Intro to PD - 53
Waste Minimization
• Before considering ‘‘end-of-pipe’’ approaches for treating and managing waste products, the design engineer should always try to minimize production of waste at the source. The hierarchy of waste management approaches is
1. Source reduction: Don’t make the waste in the first place. This is the best practice.
2. Recycle: Find a use for the waste stream.
3. Treatment: Reduce the severity of the environmental impact.
4. Disposal: Meet the requirements of the law.
Waste Minimization
• A technique that is sometimes used for waste minimization is the 5-step review:
1. Identify waste components for regulatory impact.
2. Identify waste streams for size and economic impact.
3. List the root causes of the waste streams.
4. List and analyze modifications to address the root causes.
5. Prioritize and implement the best solutions..
Intro to PD - 55
Waste Management
• When waste is produced, processes must be incorporated in the design for its treatment and safe disposal.
• The following techniques can be considered:
1. Dilution and dispersion;
2. Discharge to water sewer (with the agreement of the appropriate authority);
3. Physical treatments: scrubbing, settling, absorption, and adsorption;
4. Chemical treatment: precipitation (for example, of heavy metals), neutralization (chemical treatment);
Waste Management
5. Biological treatment: activated sludge and other processes;
6. Incineration on land or at sea;
7. Landfill at controlled sites;
8. Sea dumping (now subject to tight international control).
Note: Refer to standards and regulations
THANK YOU
