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CONCEPT OF SUSTAINABLE DEVELOPMENT

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ECONOMIC SUCCESS

ECONOMIC PROBLEMS

SOCIAL ACCEPTANCE

ENVIRONMENTAL PROTECTION

ENVIRONMENTAL DAMAGE

SOCIAL PROBLEMS

SUSTAINABLE DEVELOPMENT

Ecological sustainability demands to defend the bases of the natural life and not to exceed the stress limits of the environment. Economic sustainability means efficient utilisation of natural resources, use of renewable materials and alternative energies, and recycling of waste. Social sustainability recognises the prerogatives of the free market economy based on the social justice and the rights of individuals.

Process Design & the creative activity whereby we generate ideas and then translate them into equipment and process for producing new materials or for significantly upgrading the value of existing materials

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Today a designer should be concerned about the rational use of resources and the preservation of the natural environment.

The process should•be compact and economical in energetic consumption•offer flexibility and ready to accept other raw materials or other specifications of products

The process has to be novel, efficient, and competitive in a global business environment, and also sustainable.

Starting from a vaguely defined problem statement such as a customer need or a set of experimental results, chemical engineers can develop an understanding of the important underlying physical science relevant to the problem and use this understanding to create a plan of action and set of detailed specifications which, if implemented, will lead to a predicted financial outcome

Design Constraints

Constraints•Fixed and invariable•Relaxed or flexible

Design Process in General

The Design Objective (The Need) All design starts with a perceived need.It is important to distinguish between the needs that are ‘‘must haves’’ and those that are ‘‘should haves.’’ The ‘‘should haves’’ are those parts of the initial specification that may be thought desirable, but that can be relaxed if required as the design develops.

Setting the Design Basis

• The system of units to be used.• The national, local or company design codes that must be

followed• Details of raw materials that are available• Information on potential sites where the plant might be

located, including climate data, seismic conditions, and infrastructure availability.

• Information on the conditions, availability, and price of utility services such as fuel (gas), steam, cooling water, process air, process water, and electricity, that will be needed to run the process

Generation of Possible Design Concepts• The creative part of the design process is the generation of

possible solutions to the problem for analysis, evaluation, and selection. In this activity, most designers largely rely on previous experience—their own and that of others.

A. Modifications, and additions, to existing plant; usually carried out by the plant design group.

B. New production capacity to meet growing sales demand and the sale of established processes by contractors. Repetition of existing designs, with only minor design changes, including designs of vendors’ or competitors’ processes carried out to understand whether they have a compellingly better cost of production.

C. New processes, developed from laboratory research, through pilot plant, to a commercial process. Even here, most of the unit operations and process equipment will use established designs.

The economic incentives of a plant project, from the conceptualphase down to construction and commissioning

• The long way from an idea to a real process can be managed nowadays by means of a systemic approach. This involves systematic methodologies for designing the whole process and its sub-systems, as reaction, separations, heat exchangers network and utilities.

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• In the past, the development of a new process has been described often as a kind of 'art'. The strategy, called sometimes the engineering method, consisted of sketching a simple but inspired flowsheet, and improving it by successive layers of refinements, up to final optimisation. The experience of the designer, the expertise of the company, and the availability of pilot data were crucial.

• Nowadays, the conceptual design of processes is becoming increasingly an applied chemical engineering science. Engineers having a solid scientific background and mastering computer design tools are capable of finding much quicker innovative ideas.

• Inspiration and expertise still play an important role, as well as the availability of practical data.

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THE ORGANIZATION OF A CHEMICAL ENGINEERING PROJECT

• Phase 1: Process design, which covers the steps from the initial selection of the process to be used, through to the issuing of the process flowsheets and includes the selection, specification, and chemical engineering design of equipment. In a typical organization, this phase is the responsibility of the Process Design Group, and the work is mainly done by chemical engineers. The process design group may also be responsible for the preparation of the piping and instrumentation diagrams.

• Phase 2: Plant design, including the detailed mechanical design of equipment; the structural, civil, and electrical design; and the specification and design of the ancillary services. These activities will be the responsibility of specialist design groups, having expertise in the whole range of engineering disciplines.

Anatomy of Chemical Process

Outline of a design project

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Project Organization

Each step in the design process will not be neatly separated from the others, nor will the sequence of events be as clearly defined. There will be a constant interchange of information between the various design sections as the design develops, but it is clear that some steps in a design must be largely completed before others can be started

Project DocumentationGeneral correspondence within the design group and with :•Government departments•Equipment vendors•Site personnel•The client

Drawings:•Flow sheets•Piping and ID diagrams•Layout diagrams•Plot/site plans•Equipment details•Piping diagram•Architectural drawings•Design sketches

Calculations sheets•Design calculations•Cost estimates•Material and energy balance

Project DocumentationSpecification sheets•The design basis•Feed and products specifications •Equipment list•Spec sheets for equipments

Health , safety and environmental information•Material and safety data sheets (MSDS)•HAZOP and HAZAN documentation•Emission assessments and permit

Purchase orders•Quotations•Invoices

System Approach1. System is a combination of a several pieces of equipment integrated to

perform a special function.2. Systems Analysis is the investigation of an activity, procedure, method,

technique, or business to determine what must be done and how the operation may be best accomplished. It consists of applying mathematical techniques to the study of systems.

3. Systems Engineering is the design of a complex interconnection system of many elements to maximise an agreed-upon measure of the system performance, taking into consideration all the elements related in any way to the system.

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Systems approach consists of two steps:• Modelling, in which each element of the systems is described

and criteria for measuring performance are assigned• Optimisation, in which adjustable parameters are set in a

manner that gives the best performance of the whole system.

LIFE CYCLE MODELLING

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three basic life cycle forms: waterfall, V-model and spiral model. These forms are suited for the design of computer-based systems, but have larger applicability, particularly in the field of process engineering.

WATERFALL MODELLING

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REQUIREMENT DEFINITONS

SYSTEM DESIGN

IMPLEMENTAION AND UNIT TEST SYSTEM

TEST

•The phases must be clearly defined such as the output of one falls cleanly into the input of the next.•Waterfall model indicates that the project sequencing should be organised such to avoid feedback between phases, particularly to review the architectural (system) design.

The development of an (idealised) design project can be decomposed in four major phases: Requirements, Conceptual Design, Basic Design, and Detailed Engineering.

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• V Cycle Model: appropriate for managing complex systems when systematic validation is necessary.

• The two basic ideas are: 1)decompose the work in a

number of tasks, and 2)separate 'specification &

design' tasks from 'production' tasks.

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The left side of the cycle represents the refinement of design, while the right side describes the assembly tasks. In a V-cycle the project management and quality assurance are carried out together. Each design step is verified before proceeding to the next one, and each production task is validated against the corresponding specification task. Here verification means that the product fulfils the quality characteristics, such as consistency and completeness, while validation means that the product satisfies the specifications.

Spiral modelThe spiral life cycle model is a repeating waterfall form at

successive levels of detail. In addition, it accommodate unforeseen events by a risk-driven approach.

Similar tasks but with different objectives are performed during each cycle iteration.

The inner cycles carry out more evaluation and prototyping tasks, while the outer cycles deal with final design.

The cumulative cost versus time is measured at each level.

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CHEMICAL PRODUCTS• Commodity or bulk chemicals: low operating cost but a higher capital cost,

produced in large volumes• Fine chemicals: produced in small volumes and purchased on the basis of

chemical composition , purity and price• Specialty or effect or functional chemicals: priority tends to be given to the

function then the process of manufacture

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Process priorities for various products

Design for manufacture of a commodity: I. Relatively little product innovation, but intensive process

innovation. II. Equipment will be designed for a specific process step

Design for manufacture of fine and specialty chemicals: I. Selling into a market with low volume,II. Short product life cycle,III. Demand for a short time to market, and therefore, less time is

available for process development, with product and process development proceeding simultaneously.

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NEW CHEMICAL PRODUCT

• When a new chemical product is first developed, it can often be protected by a patent in the early years of commercial exploitation.

• For a product to be eligible to be patented, it must be novel, useful and unobvious.

• If patent protection can be obtained, this effectively gives the producer a monopoly for commercial exploitation of the product until the patent expires.

• Patent protection lasts for 20 years from the filing date of the patent. Once the patent expires, competitors can join in and manufacture the product

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Product life cycles• Product A is a poor product

that has a short life with low sales volume

• Product B is a better product, with a longer life cycle and higher sales volume.

• Product C shows high sales volume with the life of the product extended through reformulation of the product

• Product D is a shows a life cycle that is typical of commodity chemicals

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A rapid decrease in sales patent protection is lost, leading to loss of market through competition.

Commodity chemicals, sales volume grows rapidly to a high volume, but then does not decline and enters a mature period of slow growth

Directions of Process Engineering

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Flexible processes reduction

Energy saving

Quality and control

PROCESS ENGINEERING

Process Safety

Environmental performance

Raw material efficiency

Capital cost reduction

Computer Integrated Manufacturing systems designates the integration of plant operation with business activities. The integration has to consider not only planning and accounting tools, but also rigorous modelling technology. Process flexibility should be seen not only in term of variable production rate, but also in term of composition of the feedstock.Reduced inventory asks for the suppression of intermediate costly storage facilities

process intensification lead tosignificant reduction in the equipment size and capital costs.High valorisation of raw materials is the factor with the strongest impact on process efficiency. In this respect, the breakthrough element is the chemistry. Here we mean also the development of more active and selective catalysts. Enhancing the selectivity of reactions can eliminate material and energy recycles and contributes significantly to massive cost reduction

Modem process design should aim to zeroeffluent plants by minimisation of gaseous emissions and of process waste, iincluding wastewater.

Wide-range implementation of Pinch Point Analysis

Reduction of imp urities and by-products, and implementing advanced control systems can ensure constant product qualityInherently safety can be achieved by incorporating more non-linear analysis in process dynamics and control