【正文】 nozzle locations, and materials), all piping (including sizes, materials, and valves), all instrumentation (including locations and types of sensors, control valves, and controllers), and all safety systems (including safety valve and rupture disk locations and sizes, flare lines, and safe operating conditions).(3). Equipment Specification sheets are sheets of detailed information on all the equipment precise dimensions, performance criteria, materials of construction, corrosion allowances, operating temperatures, and pressures, maximum and minimum flow rates, and the like. These “spec sheets” are sent to the equipment manufacturers for price bids and then for building the equipment.3. Construction After the equipment manufacturers (vendors) have built the individual pieces of equipment, the pieces are shipped to the plant site (sometimes a challenging job of logistics, particularly for large vessels like distillation columns). The construction phase as the assembling of all the ponents into a plete plant. It starts with digging holes in the ground and pouring concrete for foundations for foundations for large equipment and buildings (., the control room, process analytical laboratory and maintenance shops).After these initial activities, the major pieces of equipment and the steel superstructure are erected. Heat exchangers, pumps, piping, instrument sensors, and automatic control valves are installed. Control system wiring and tubing are run between the control room and the plant. Electrical wiring, switches, and transformers are installed for motors to drive pumps and pressors. As the process equipment is being installed, it is the chemical engineer` s job to check that it is all hooked together properly and that each piece works correctly.This is usually a very exciting and rewarding time for most engineers. You are seeing your ideas being translated from paper into reality. Steal and concrete replace sketches and diagrams. Construction is the culmination of years of work by many people. You are finally on the launch pad, and the plant is going to fly or fizzle! The moment of truth is hand. Once the check out phase is plete, “startup” begins. Startup is the initial missioning of the plant. It is a time of great excitement and roundtheclock activity. It is one of the best learning grounds for the chemical engineer. Now you find out how good your ideas and calculations really are .The engineers who have worked on the pilot plant and on the design are usually part of the startup team.The startup period can require a few days or a few months, depending on the newness of the technology, the plexity of the process, and the quality of the engineering that has gone into the design. Problems are frequently encountered that require equipment modifications. This is time consuming and expensive: just the lost production from a plant can amount to thousands of dollars per day. Indeed, there have been some plants that have never operated, because of unexpected problems with control, corrosion, or impurities, or because of economic problems.The engineers are usually on shift work during the startup period. There is a lot to learn in a short time period. Once the plant has been successfully operated at its rated performance, it is turned over to the operating or manufacturing department for routine production of products.4. Manufacturing Chemical engineers occupy a central position in manufacturing (“operations” or “production,” as it is called in some panies). Plant technical service groups are responsible for the technical aspects of running an efficient and safe plant. They run capacity and performance tests on the plant to determine where the bottlenecks are in the equipment, and then design modifications and additions to remove these bottle necks. Chemical engineers study ways to reduce operating costs by saving energy, cutting raw material consumption, and reducing production of offspecification products that require reprocessing. They study ways to improve quality and reduce environmental pollution of both air and water.In addition to serving in plant technical service, many engineers have jobs as operating supervisors. These supervisors are responsible for all aspects of the daytoday operation of the plant, including supervising the plant operators who run the plant roundtheclock on a threeshift basis, meeting quality specifications, delivering products at agreedupon times and in agreedupon quantities, developing and maintaining inventories of equipment spare parts, keeping the plant well maintained, making sure safe practices are followed, avoiding excessive emissions into the local environment, and serving as spokespersons for the plant to the local munity .5. Technical Sales Many chemical engineers find stimulating and profitable careers in technical sales. As with other sales positions, the work involves callingon customers, making remendations on particular products to fill customer` s needs, and being sure that order are handled smoothly. The sales engineer is the pany` s representative and must know the pany` s linewell. The sales engineer` s ability to sell can greatly affect the progress and profitability of the pany.The marketing of many chemicals requires a considerable amount of interaction between engineers in the pany producing the chemicals and engineers in the pany using the chemical. This interaction can take the form of advising on how to use a chemical or developing a new chemical in order to solve a specific problem of a customer.When the sales engineer discovers problems thatcannot be handled with confidence, he or she must be able to call on the expertiseof specialists. The sales engineer may sometimes have to manage a joint effort among researchers from several panies who are working together to solve a problem.6. Research Chemical engineers are engaged in many types of research. They work with