The Basics of Process Technology (Основы технологических процессов). Учебное пособие

TEST (VERSION 2)

1. Закончите предложения, используя следующие слова: adsorption, hydrodynamics, thermal radiation, thermodynamics, fractionation,

1.… is fluid dynamics applied to liquids, such as water, alcohol, oil, and blood.

2.… is electromagnetic radiation emitted from the surface of an object which is due to the object's temperature.

3.A … is separation of the mixture into its component parts, or fractions, based on the differences in their volatilities.

4.… is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics.

5.… is a process that occurs when a gas or liquid solute accumulates on the surface of a solid adsorbent, forming a molecular or atomic film.

2.Подберите эквивалентный перевод словосочетаний из колонки А в колонке В

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3.Определите, к какой из следующих тематик относятся следующие словосочетания:

Adjacent teeth, fin, piston, surrounding, conservation, heat transfer, definite state, cavitation, impeller, absolute zero, plate, surface area.

4. Определите и исправьте неточности в следующих предложениях

∙In fluid mechanics, the Reynolds number is the ratio of

viscous forces (µ/L) to inertial forces (vsρ) and consequently it quantifies the relative importance of these two types of forces for given flow conditions.

∙The gear pump traps a fixed quantity in the space between adjacent teeth and the casing, and total flow rate is the quantity delivered by the pump for each piston stroke.

∙Heat convection is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and hence acts to even out temperature differences.

∙Real objects behave as full-ideal black bodies, and instead the emitted radiation at a given frequency is a fraction of what the ideal emission would be.

∙For efficiency, heat exchangers are designed to minimize the surface area of the wall between the two fluids, while maximizing resistance to fluid flow through the exchanger.

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∙A typical plate heat exchanger is usually used for higherpressure applications.

∙The less reflux and less trays provided, the better is the tower's separation of lower boiling materials from higher boiling materials.

5.Переведите следующие предложения

∙Турбулентный поток характеризуется высокими числами Рейнольдса и пульсациями скоростей, которые приводят к появлению вихрей и интенсивному перемешиванию потока.

∙В вихревых насосах для передачи энергии от рабочего колеса к жидкости и создания напора используется энергия вихревого движения жидкости.

∙Большую роль играет адиабатный процесс, который происходит без теплообмена между системой и внешней средой.

∙В соответствии со вторым законом термодинамики тепло самопроизвольно переходит от более нагретого тела к менее нагретому.

∙Механизм процесса адсорбции отличается от механизма абсорбции тем, что извлечение вещества осуществляется твердым, а не жидким поглотителем

∙Цеолиты являются полярными алюмосиликатами, выделяющими воду при высоких значениях температуры.

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ТЕКСТЫ ДЛЯ ДОМАШНЕГО ЧТЕНИЯ

Text 1

ENGINEERING

Engineering is the discipline of acquiring and applying scientific and technical knowledge to the design, analysis and construction of works for practical purposes. The American Engineers' Council for Professional Development, also known as ECPD, defines Engineering as: "The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property."

Historically the main branches of engineering are categorized as follows:

∙aerospace engineering - the design of aircraft, spacecraft and related topics.

∙chemical engineering - the conversion of raw materials into usable commodities.

∙civil engineering - the design and construction of public and private works, such as infrastructure, bridges and buildings.

∙electrical engineering - the design of electrical systems, such as transformers, as well as electronic goods.

∙mechanical engineering - the design of physical or mechanical systems, such as engines, powertrains, kinematic

chains and vibration isolation equipment.

Chemical Engineering, like its counterpart Mechanical Engineering, developed in the nineteenth century during the Industrial Revolution. Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale

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production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants. The role of the chemical engineer was the design of these chemical plants and processes.

Engineers apply the sciences of physics and mathematics to find suitable solutions to problems or to make improvements to the status quo. If multiple options exist, engineers weigh different design choices on their merits and choose the solution that best matches the requirements. The crucial and unique task of the engineer is to identify, understand, and interpret the constraints on a design in order to produce a successful result. It is usually not enough to build a technically successful product; it must also meet further requirements. Constraints may include available resources, physical, imaginative or technical limitations, flexibility for future modifications and additions, and other factors, such as requirements for cost, safety, marketability, productibility, and serviceability. By understanding the constraints, engineers derive specifications for the limits within which a viable object or system may be produced and operated.

1.Ответьте на вопросы:

∙ What is engineering?

∙ What different types of engineering can you name? ∙ Do you want to be an engineer?

∙ Why did you decide to study at chemical faculty of KSTU? ∙ What is your future specialty (profession)?

∙ What are the main skills and strains of the engineer?

2.Составьте рассказ о своей инженерной деятельности, включив в него описание университета, факультета, специальности, будущей профессии, научной или дипломной работе на вашей кафедре.

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Text 2

DISTILLATION

Distillation is a method of separating chemical substances based on differences in their volatilities in a boiling liquid mixture. Distillation usually forms part of a larger chemical process, and is thus referred to as a unit operation.

Figure 1. Laboratory distillation set-up: 1 Heat source

2 Still pot

3 Still head

4 Thermometer/Boiling point temperature

5 Condenser

6 Cooling water in

7 Cooling water out

8 Distillate/receiving flask

9 Vacuum/gas inlet

10 Still receiver

11 Heat control

12 Stirrer speed control

13 Stirrer/heat plate

14 Heating (Oil/sand) bath

15 Stiring means e.g. magnetic follower, antibumping granules or mechanical stirrer

16 Cooling bath.

The application of distillation can roughly be divided in four groups: laboratory scale (fig. 1), industrial distillation, distillation of herbs for perfumery and medicinals (herbal distillate) and food processing.

The main difference between laboratory scale distillation and industrial distillation is that laboratory scale distillation is often performed batch-wise, whereas industrial distillation often occurs continuously. In batch distillation, the composition of the source material, the vapors of the distilling compounds and the distillate change during the distillation. In batch distillation, a still is charged

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with a batch of feed mixture, which is then separated into its component fractions which are collected sequentially from most volatile to less volatile, with the bottoms (remaining least or nonvolatile fraction) removed at the end. The still can then be recharged and the process repeated. In continuous distillation, the source materials, vapors and distillate are kept at a constant composition by carefully replenishing the source material and removing fractions from both vapor and liquid in the system. This results in a better control of the separation process.

Heating an ideal mixture of two volatile substances A and B (with A having the

higher volatility, or lower

boiling point) in a batch

distillation setup until the

mixture is boiling results in a

vapor above the liquid which

contains a mixture of A and

B. The ratio between A and B in the vapor will be different from the ratio in the liquid: the ratio in the liquid will be

determined by how the original mixture was prepared, while the ratio in the vapor will be enriched in the more volatile compound. The vapor goes through the condenser and is removed from the system. This in turn means that the ratio of compounds in the remaining liquid is now different from the initial ratio (i.e. more enriched in B than the starting liquid). The result is that the ratio in the liquid mixture is changing, becoming richer in component B. This causes the boiling point of the mixture to rise, which in turn results in a rise in the temperature in the vapor, which results in a changing ratio of A : B in the gas phase (as distillation continues, there is an increasing proportion of B in the gas phase). This results in a slowly changing

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ratio A : B in the distillate. If the difference in vapor pressure between the two components A and B is large (generally expressed as the difference in boiling points), the mixture in the beginning of the distillation is highly enriched in component A, and when component A has distilled off, the boiling liquid is enriched in component B.

Continuous distillation is an ongoing distillation in which a liquid mixture is continuously (without interruption) fed into the process and separated fractions are removed continuously as output streams as time passes during the operation. Continuous distillation produces at least two output fractions, including at least one volatile distillate fraction, which has boiled and been separately captured as a vapor condensed to a liquid. There is always a bottoms (or residue) fraction, which is the least volatile residue that has not been separately captured as a condensed vapor.

The disstillation is used to separate crude oil into more fractions for specific uses such as transport, power generation and heating. Water is distilled to remove impurities, such as salt from sea water. Air is distilled to separate its components - notably oxygen, nitrogen and argon - for industrial use. Distillation of fermented solutions has been used since ancient times to produce distilled beverages with a higher alcohol content.

Ответьте на вопросы:

∙What is the distillation?

∙Can you describe the process shown in the figure 1?

∙What different types of distillation do you know?

∙What is the difference between laboratory scale distillation and industrial distillation?

∙What two fractions are formed in the process of continuous distillation?

∙What is the operation principle of the unit shown in the figure 2?

∙What are the practical applications of distillation process?

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Text 3

CRUSHER

A crusher is a machine which uses a metal surface to break materials, typically minerals. Crushers are commonly classified by the degree to which they fragment the starting material, primary crushers handling coarse materials, tertiary and quaternary crushers reducing finer gradations. Typically, crushing is followed by milling if the materials need to be further reduced. From an extractive metallurgical standpoint, there is a difference between crushing and grinding. Crushing is a preliminary step to ensure that ore does not exceed certain dimensions which a grinder is capable of handling.

There are different types of crushers: jaw, gyratory, impact crushers and others.

Jaw crusher. A jaw or toggle crusher consists of a set of vertical jaws, one jaw being fixed and the other being moved back and forth relative to it by a cam or pitman mechanism. The jaws are farther apart at the top than at the bottom, forming a tapered chute so that the material is crushed progressively smaller and smaller as it travels downward until it is small enough to escape from the bottom opening. The movement of the jaw can be quite small, since complete crushing is not performed in one stroke. The inertia required to crush the material is provided by a weighted flywheel that moves a shaft creating an eccentric motion that causes the closing of the gap. Single and double toggle jaw crushers are constructed of heavy duty fabricated plate frames with reinforcing ribs throughout. The crushers components are of high strength design to accept high horsepower draw. Manganese steel is used for both fixed and movable jaw faces. Double Toggle jaw crushers may feature hydraulic toggle adjusting mechanisms.

Gyratory crusher. A gyratory crusher is similar in basic concept to a jaw crusher, consisting of a concave surface and a conical head; both surfaces are typically lined with manganese steel surfaces. The inner cone has a slight circular movement, but does not rotate; the

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movement is generated by an eccentric arrangement. As with the jaw crusher, material travels downward between the two surfaces being progressively crushed until it is small enough to fall out through the gap between the two surfaces.

Impact crushers. Impact crushers involve the use of impact rather than pressure to crush material. The material is contained within a cage, with openings on the bottom, end, or side of the desired size to allow pulverized material to escape. This type of crusher is usually used with soft and non-abrasive material such as coal, seeds, limestone, gypsum or soft metalic ores.

The proper selection of primary crushers in an aggregate or mining plant is extremely important. Variables include, but they are not limited to, material size, abrasion, work index, particle size distribution, clay content, etc. The factors to be considered in the correct selection of a primary crusher are:

∙The maximum feed size the crusher is expected to accept.

∙The product size allowed to be fed to the secondary crushers.

∙The production rate required yielding this correct product size.

∙The abrasion index and work index of the mineral to be crushed.

∙The availability of maintenance for the crusher.

The crushers are widely used in metallurgy, mineral resource industry and woodworking industry.

Ответьте на вопросы:

∙What types of crushers can you name?

∙What is the operation principle of the gyratory crusher?

∙What is the operation principle of the impact crusher?

∙What is the operation principle of the toggle crusher?

∙What are the main factors to be considered for the correct selection of crusher type?

∙What is the practical application of crushers?

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