Translate the word combinations into Russian and use them in your own sentences

Propulsion boilers, location of fire and water spaces, gases of combustion, water circulation, natural circulation boilers, forced circulation boilers, ascending mixture, descending body, natural differences in density.

Choose the proper verb form, active or passive.

1. Boiler design may /vary; varied; to vary/ considerably.

2. Propulsion boilers /proved; provides; are provided/ steam for ship’s propulsion.

3. Auxiliary boilers /supplies; supplying; supply/ steam and hot water for galley and heating.

4. The gases /passes; to pass; pass / through the tubes in the fire-tube boilers.

5. The metal surfaces of the tubes /are heated; are heat; heat/ by the gases.

6. Water-tube boilers may /be classed; are classed; classed/ as natural circulation boilers or forced circulation ones according to the method of water circulation.

TEXT C

Exhaust Gas Boilers

Exhaust gas boilers use the exhaust gases from an internal combustion engine for the generation of steam. These consist of some form of an exhaust gas heat exchanger mounted in the main engine uptake.

Exhaust gas boilers produce steam by using the heat of the exhaust gases of marine diesel engines, thus saving thermal energy that otherwise would get lost.

The exhaust gases, by passing through the tube banks, give up heat and afterwards are sent to the funnel at lower temperatures.

Where it is necessary, the exhaust gas boiler can be equipped with an economizer and with a superheater: the first one is fitted to preheat feed water, thus increasing heat recovery; the second one is used when superheated steam is required.

The exhaust gases of diesel engines still contain thermal energy that is superior to 30% of the total heating value of the fuel.

The temperatures of the exhaust gases vary from 270°C to 320°C for slow two- stroke engines, and from 350°C to 480°C for medium speed four-stroke engines. Therefore it seems extremely necessary and important to recover this residual energy by using exhaust gas boilers that have been developed especially for the continuous and heavy service on motorships.

Vocabulary

exhaust gas boiler утилизационный котел

consist (of), v состоять (из)

exhaust gas heat exchanger утилизационный теплообменник

mount, v устанавливать; монтировать

uptake, n дымоход

thus, adv таким образом

save, v сохранять

otherwise, adv в противном случае, иначе

heat recovery утилизация тепла

vary, v изменяться

therefore, adv поэтому

E X E R C I S E S

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