unit 3 text statements

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Pipeline Network Operation

Part I

Pipeline operation is monitored by special personnel.

Operators watch flow rate, pressure and product movement at check points.

Controllers watch for pressure and flow rate inconsistencies (несоответствия) in order to detect leaks and other problems Operators shut down and isolate pipeline sections in case of accident.

Maintenance crews also ensure pipeline integrity. They inspect welding and valves, repair pipelines, check corrosion protection systems and maintain electronic equipment. They also perform daily maintenance, assist pipeline repair and replacement, provide emergency response and assist local emergency crews.

Pumping stations are located along the pipeline. They pump product, adjust pressure and throughput, monitor product flow and other parameters. If the throughput has to be increased, other pumping stations are added to the route. Their position is selected depending on the problem area location. In the mountains, for example, more power is necessary to push products through pipelines.

Gas transportation system is a pipeline network used to transport natural gas from production sites to consumption zones. The system includes compressor stations (CS) that pressurize natural gas transported through a pipeline. They are located at 40 to 100 mile intervals. CS size and compressors number depend on the pipe diameter and gas volume. location CS depends on the terrain and the nearby wells number. Mountain terrain and numerous wells require more CS. Gas in CS is pressurized by special turbines driven by motors and engines.

Part II

Compressor stations

Head CS are located at the initial point of gas pipelines.

Booster CS are located along the gas pipeline route.

Scrubbers (скруббер), strainers (фильтр предварительной очистки) or filter separators (сепаратор тонкой очистки) of the CS release gas from liquids and solid particles before it enters the compressor. "Dry" gas in the pipeline contains some water and hydrocarbon liquids, which condense in the pipeline. Liquid separators purify natural gas, collect and store liquids for sale or disposal. After liquid separators gas enters compressors.

Compressors are driven by three types of engines.

a) Turbine/centrifugal Compressor is powered by gas-fired turbine. The turbine operates a centrifugal compressor, which contains a type of fan that compresses and pumps the natural gas through the pipeline. They are powered by gas taken from the pipeline.

b) Electric Motor/centrifugal Compressors are driven by high voltage electric motors. Such motors do not burn hydrocarbons and don't need environmental permits. But they require a reliable source of electricity.

c) Reciprocating Engine/reciprocating Compressors are driven by piston engines (поршневыми двигателями) fueled by natural gas from the pipeline. The compressor pistons (поршень компрессора) and the power pistons (приводной поршень) are connected to a common crankshaft (коленчатый вал). Such compressors can adjust gas volume to customer’s needs.

Pumping stations

Gathering stations (GS) are located at the initial point of a pipeline and give petroleum a strong initial drive. They collect crude from field tanks by gathering lines. Besides pipelines, they collect petroleum by tank tracks. Their pumping units are driven by small electric motors or engines powered with gas, diesel oil, or liquefied petroleum gas. The mode of GS operation depends on its size and function. The crude from them is pumped to another GS located closer to the crude main or directly to that main.

Trunk-line stations are located along the main line and used for further crude injection to continuous flow. Such stations are equipped with centrifugal units connected to internal-combustion engines through increasers (переходная муфта). If injected crude composition differs from the flow composition such crude is pumped as a separate batch. Then the batch is delivered to separate customers or into different tanks. If a trunk-line station is near an oil field it can be used as a gathering station.

Ex.6. Agree or disagree with the following statements:

1) Leak detection is a standard function of pipeline monitoring systems.

You are right. Pipeline controllers are responsible for leak detection. They watch for inconsistencies, monitor instruments, evaluate pressure and flow rates. If a sign of leak is detected they perform additional investigation. In the case of an accident, pipeline operators shut down pipeline section and maintenance crew repairs a leak.

2) Pipelines operators work to ensure the integrity of pipeline infrastructure.

You are right, but besides operators, pipeline integrity is ensured by pipeline controllers and maintenance crews. They watch flowrates and pressures, monitor inconsistences, shut down pipeline sections in case of accident. They inspect welding operations, corrosion protection, provide pipeline repair and replacement. They also provide emergency response and assist local emergency responders.

3) All gas pipelines are equipped with pumping stations.

I'm afraid you are wrong. They are equipped with compressor stations which pressurize natural gas transported through a pipeline.

Pumping stations are used at liquid pipelines transporting crude oil and petrochemical products.

4) A piping system directs gas from gas compressors to separators.

I'm afraid you are wrong. A piping system directs gas from separators where gas is cleaned from liquids and solid particles to compressors where gas is pressurized to increase its throughput.

5) There are two types of engines that drive the compressors.

I'm afraid you are not quite write. There are three types of engines, that drive compressors:

Gas-fired turbines, which operate centrifugal compressors, pressurizing and pumping gas,

Electric motors, that are ecologically safe but require source of electricity and

Reciprocating, or piston engines, which are powered by pipeline gas. They help to adjust gas volume to customers demand .

6) The turbine serves to operate centrifugal compressors.

Yes, you are right. The turbine operates a centrifugal compressor which contains a large fan that compresses and pumps the natural gas through the pipeline. Besides, turbine compressors are operated by electric motors.

7) The centrifugal compressor is not driven by high voltage electric motors.

I'm afraid you are wrong. Centrifugal compressor can be driven by a high voltage electric motor. Electric motors do not burn hydrocarbons and don't need environmental permits but require reliable sources of electricity.

8) Reciprocating pistons compress natural gas.

Yes, you are right. Reciprocating compressor pistons compress natural gas. The advantage of reciprocating compressors is that the volume of gas pushed through the pipeline can be adjusted to customer’s demand.

9) All oil pipelines are equipped with compressor stations.

I'm afraid you are wrong. Oil pipelines are equipped with pumping stations which can be of two types – gathering and trunk-line stations.

10) Numerous reciprocating pumps are used at gathering stations.

Yes, you are right. Gathering stations contain small reciprocating pumps which give petroleum a strong initial pulse. They are driven by engines or electric motors powered with gas, diesel oil or liquefied petroleum gas A typical gathering station can move from a hundred to several thousand barrels of crude daily.

11) Pumps used in trunk-line stations are high-speed centrifugal units.

Yes, you are right. Centrifugal units are used in trunk-line stations. They are connected through increaser to internal-combustion engines.

12) Trunk-line pumping stations are located at the beginning of oil pipelines.

You are not quite right, I'm afraid. Trunk-line stations are located along the main line. They are used to further inject crude into continuous flow. But I'd like to add that trunk-line station can serve as a gathering station if near the oil source.

Ex.7. Answer the following questions:

Part I:

1) What is the standard mode of any pipeline operation?

Pipelines operate every day round-the-clock. Their operation, maintenance and control are performed by pipeline operators, controllers and maintenance crews. Pipeline operators watch the rate, pressure and product movement. Pipeline controllers monitor pressure and flowrate readings, perform additional investigation in case of inconsistency and shut down pipeline section in case of accident.

Maintenance crews provide pipeline integrity. They provide welding and valve inspections, repair pipelines, maintain corrosion protection systems and electronic equipment. They repair and replace pipelines, assist local emergency responders in case of a pipeline accident.

2) What pipeline operation parameters are monitored at the control point?

Such parameters as flowrate, pressure and mode of product movement are monitored at control points.

3) What are the basic functions of pipeline controllers?

Pipeline controllers watch for inconsistencies, monitor instruments, evaluate pressure and flow rates. If a leak evidence is detected they perform additional investigations.

4) In what cases is it necessary to carry out additional investigation?

If evidence of a possible leak is detected additional investigations are performed by pipeline controllers.

5) Name the initial response actions to be taken by pipeline operators in case of an accident.

In case of an accident, pipeline operators shut down or isolate damaged pipeline sections quickly and safely.

6) Can you name the major purpose of pumping stations? Where are these stations located?

The main function of Pumping Stations (PS) is to provide movement of liquid products along the pipeline. They maintain the throughput, adjust the pressure, monitor flowrate and other parameters. PS are located along the pipeline route. Their location depends on pipeline diameter, product volume, proximity to other equipment and terrain: in mountain areas more PS’s are constructed.

7) What pipeline operation parameter primarily depends on the number, capacity and proper operation of pumping systems?

The main parameter depending on pumping system operation is the pipeline throughput. Proper operation of pumping stations also provides smooth and uninterrupted product supply.

10) What circumstances is it necessary to consider when selecting pipeline location and construction parameters?

In selecting PS’s position specialists consider their proximity to other equipment and the terrain: for example, when the line goes over a mountain range it needs more PS.

11) What is the basic purpose of compressor stations?

A Compressor Station (CS) provides natural gas transportation. CSs maintain pipeline capacity through increasing the gas pressure by its pressurizing in gas compressor units. Natural gas transported through a gas pipeline should be constantly pressurized at intervals of 40 to 100 miles.

2) Are compressor stations different from pumping stations?

Their purpose is the same but the equipment used and operation modes differ.

Part II:

13) Where are head and booster compressor stations usually located?

Head compressor stations (CS) are located at the initial point of the gas pipelines. Booster CS are located along the gas pipeline route at intervals of 40 to 100 miles.

14) Name the purpose of filter separators.

The filter separators at CS purify natural gas. They release the gas from liquids and dirt particles prior to compression. The obtained liquids are collected and stored for sale or disposal.

15) Name the basic types of compressors. What is the principle of their operation?

a) Centrifugal Compressors operated by gas-fired turbine. They contain a type of fan which compresses and pushes gas through the pipeline.

b) Centrifugal Compressor driven by high voltage electric motors. Electric motors do not burn hydrocarbons and don't need environmental permits. Nevertheless, they require a reliable source of electricity.

c) Reciprocating Compressor driven by reciprocating (piston) engines fueled by natural gas from the pipeline. They can adjust the volume of gas to any customer demand. This is their main advantage.

16) What are the major types of pumping stations?

I know gathering and trunk-line stations.

Gathering stations are located at the starting point of the pipeline and provide the crude with a strong initial pulse.

Trunk-line stations are located along the main line and provide further injection of crude into continuous flow. They are also used to track butches of crude with different composition. Trunk-line stations can be used as gathering stations if it is located near the oil source.

17) What can you say about the gathering stations location and purpose?

Gathering stations are located at initial point of a pipeline and give petroleum a strong initial pulse. They collect crude from field tanks by gathering pipelines. They also get crude from other sources such as tank tracks. They contain reciprocating pump units driven by small electric motors or engines powered with gas, diesel oil, or liquefied petroleum gas. The crude from such stations is pumped to another gathering station located closer to the crude main or directly to the trunk-line station.

18) What can you say about the trunk-line stations location and purpose?

Trunk-line stations are located along the main line and used for further injection of crude into continuous flow. Their centrifugal units are driven by internal-combustion engines. If the crude composition differs from flow composition, this crude is pumped as a separate batch. A trunk-line station can be used as a gathering station if it is located near the oil source.