Text 12

Read, translate the text "Pipeline valves" and make the annotation of it.

Pipeline valves

Pipeline valves are designed to control flows of oil transported through pipelines. Valves are divided into three classes: stop valves, control valves and safety valves.

Stop valves (gate valves) are used to fully close pipeline flow area, control valves (pressure controllers) - to change pressure or flow rate of pumped fluid, safety valves (check valves and relief valves) - to protect pipelines and equipment when acceptable pressure is exceeded, and also to prevent fluid back flows. Gate valves are stop devices, in which flow area is closed by the gate forward motion in direction at right angle to oil flow. By design a gate valve represents an integral cast or welded body equipped with two nipples to connect to a pipeline (by means of flanges or welding) and a stem connected to a stop element and controlled by means of a hand wheel or a special actuator. Place of the stem outlet from the body is packed with sealing.

Devices used for automatic maintenance of pressure at the required level are called controllers.

Devices preventing pipeline pressure increase above the set value are called safety valves. Safety valves of closed type releasing a part of fluid from the place of higher pressure origination are used on oil lines. Device for prevention of fluid reverse flow in a pipeline is called a check valve. Swing check valves with the gate revolving on its horizontal axis are used for oil pumping.

Text 13

Read, translate the text "Refineries" and make the annotation of it.

Refineries

In general, refineries are divided into simple and complex, but analysts also often use the term «very complex».

Simple refinery processes include distillation of crude oil, hydro treatment of intermediate distillates and catalyst reforming of naphtha.

Complex refinery processes include the same plus catalyst cracker and alkylation and gas fractionation plants.

Very complex refinery processes include the same what is performed at the complex refinery plus units to produce defines or to crack residue (for example, coking unit).

Refining of any crude oil at the very complex refinery produces more light petroleum products than at the simple refinery.

In standard industry model volumes of petroleum products can be calculated for each type of crude oil at each type of refinery. This helps to find out how efficient can be refining of specific type of oil for specific type of refinery. For that purpose calculation results are reviewed with two different methods: making «a snap» of general industry picture and studying dynamics of situation changes in its components.

Modern communication means and computer technologies provide for an opportunity to weekly calculate and issue data that assist in evaluating commercial interest of buyers in various types of crude oil. Two geographical points are accounted - the point where prices for petroleum products are fixed and the point where the price for crude oil is fixed. The prices for the petroleum products are normally fixed in the place where the crude is refined. The price for the crude oil can be fixed in the same place but also can be fixed in the place where the crude is produced.