Expansion turbines

ETG I and ETG II expansion turbines are used for energy efficient reduction of gas pressure in the control and transmission stations of gas pipelines and in chemical plants.

The possibility of using different flow media to drive the turbines
Certification for operation in a hazardous explosive environment

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These turbines are designed to operate with natural gas, coke-oven gas, cold and hot air and nitrogen, CO₂, and the Organic Rankine Cycle, and they are used to produce electricity.
They provide quick and accurate output pressure control, minimum gas leakage through shaft seals and safe operation in a potentially explosive hazardous environment.
When working with hazardous gases, they are equipped with a DGS (Dry Gas Seal) from renowned manufacturers. They are delivered on a common frame with a gearbox, or also with a powered machine.

In the case of natural gas expansion turbines, we also provide a bypass line with a special quick-opening valve that replaces the turbine during its sudden shutdown, and a device for preheating the gas before it enters the turbine. It is necessary to ensure that the temperature of the gas coming out of the turbine is positive, ranging from 5 to 40 °C, depending on the customer's requirement. The heat from the turbine oil cooler and the generator cooler can also be used to heat the gas through another heat exchanger that is placed in front of the main gas heater; this increases the production of electricity or reduces the costs for heating the gas. In this case, the cooling water circuit is not necessary to cool the turbine's lubricating oil and the generator.

The configuration of the expansion turbines is similar to that of STG I and STG II steam turbines.
The differences mostly lie in the materials used, the design of the flow parts and the external seals on the shaft.

Depending on the input and output parameters of the flow medium, regulation by rotating the distributor blades is often used, which allows optimum efficiency to be achieved within a wide range of gas flow rates and maximization of the electricity generation even at a heavily varying gas expansion pressure in the turbine.
Necessary certificates and revisions are naturally also supplied. The turbines are supplied along with their installation in an engine room or for outdoor applications.

ETG I expansion turbines

A series of single-shaft turbines equipped with only one turbine stage on the shaft overhang in two basic modifications - radial and axial.
They are characterized by their high efficiency in comparison with competing products of the same design thanks to a wide range of specially designed turbine stages.

ETG II expansion turbines

These are double-shaft turbines with a high-pressure and low-pressure ETG I module, which are connected in series. They are equipped with one turbine stage on each shaft. The stages are in two basic modifications - radial and axial. They are characterized by their high efficiency in comparison with competing turbines of the same design as well as multi-stage axial turbines in terms of parameters and price, thanks to a wide range of specially designed turbine stages.

Turbine parameters

Technical parameters	ETG I expansion turbines	ETG II expansion turbines
Inlet gas:	pressure up to 6.5 MPa., max. temperature 550 °C, flow rate up to about 150 thousand Nm3/hr.	pressure up to 6.5 MPa., max. temperature 550 °C, flow rate up to about 300 thousand Nm3/hr.
Governing:	nozzle or throttle governing with one control valve	nozzle or throttle governing with one control valve
Clutch power:	up to 6 MW	up to 10 MW
Outlet gas:	pressure up to 2.5 MPa	pressure up to 2.5 MPa
Gas heating:	in the natural gas turbine, the gas is typically heated before it enters the turbine	In the natural gas turbine, the gas is heated alternatively with one heater before the gas enters the turbine, or in two heaters, the first placed in front of the turbine inlet and the second in the transition pipeline between the high-pressure and low-pressure module. The choice between these options depends mainly on the temperature of the medium used to heat the gas.

Installation in hazardous environments

PBS expansion turbines are supplied with certification and revision for operation in hazardous explosive environments.

Different media

The possibility of using different flow media to drive gas turbines enables the use of locally available sources.

Service, spare parts and overhauls of power engineering equipment

We offer our customers a comprehensive range of turbine set, boiler and boiler island maintenance services.

We provide all repairs in the framework of revisions, as well as outside of this framework in the case of sudden failures or breakdowns. The turbine repairs can range from medium repairs of individual components to overhauls of machinery including auxiliary equipment.

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