Gas treatment is a complicated integrated process
Modern gas treatment (Midstream) of various types and initial quality is always an integrated process, in which it is required in aggregate to ensure the set design parameters of gas in terms of purity, humidity, temperature, pressure, flow rate, etc.
A special stage in the continuous process of gas treatment is compression. To compress gas to the required working pressure - for the purpose of transporting it or feed it to gas-using equipment – there are used booster compressor stations consisting of one or several compressor units.
Other tasks are solved by special equipment of the appropriate designation and modification:
- Fuel gas treatment units;
- Packaged gas treatment units;
- Treatment units for fuel and start-up gas;
- APG treatment systems;
- Natural gas treatment systems;
- Multi-module gas treatment units.
The possibilities of facilities, systems and units of gas treatment will be considered on the examples of the implementation of the projects of the Group of Companies ENERGAS.
ENERGAS IS CONCENTRATION OF EXPERIENCE
Performance of the entire gas treatment complex is the main profile of ENERGAS Group, which since 2007 has successfully implemented more than 120 such projects. For them, there have been delivered and put into operation 243 process units that provide transportation of gas or operate in conjunction with different types of gas-using equipment - gas turbine and gas reciprocation units, gas pumping units, boilers, etc.
In the oil and gas industry, ENERGAS equipment treats gas of various types at 42 fields (associated petroleum gas, natural gas, condensate de-ethanization gas, Cenomanian water gas).
The relevant units operate at 67 facilities of the extracting industries complex. These are auxiliaries power supply complexes and plant power stations, oil treatment units, central processing facilities, oil check facilities, booster pumping stations, main transfer pumping stations, preliminary water removal units, central production facilities, central oil/gas gathering stations, terminal separation units, condensate de-ethanization units, complex gas treatment units.
In the power industry, ENERGAS equipment provides high-quality fuel gas to 60 modern power units (cogeneration, trigeneration, combined cycle, simple cycle). The total electric capacity of these power units is more than 4 300 MW.
A unique experience in the operation of process systems and modular gas treatment units has been gained by the joint use with gas turbine equipment of leading Russian and world manufacturers: "UEC-Gas Turbines" and NPO "Saturn", "UEC-Perm Motors" and "UEC-Aviadvigatel", Kazan and Ufa Engine-Building Production Unions, Nevsky Zavod, General Electric, Siemens, Alstom, Turbomach, Centrax, Solar, Pratt & Whitney, Rolls-Royce, Kawasaki.
PROFILE TESTED BY TIME
The companies ENERGAS, ServicENERGAS are united not only by the general brand. Our companies have agreed targets and tasks, which are achieved through professional specialization and mutual responsibility for the quality of modular gas treatment units.
Reliable and efficient operation of process equipment is ensured by a combination of special (individual) design and modern high-quality production.
Design and production is carried out here by ISO 9001 standards, according to the rules and regulations established in Russia. The equipment is developed taking into account the field of use, operating conditions, quality and composition of source gas, the type and characteristics of the coupled units, special design requirements.
When developing the project, we perform calculations in a special program that allows us to create a theoretical model of gas behavior for given parameters in terms of temperature, pressure, and component composition. As a result, the customer is offered several algorithms for solving the tasks, from which the optimal variant is selected during the negotiation process - in terms of complexity, timing and cost of implementation.
Depending on operating conditions and the environment, ENERGAS gas treatment units are supplied in container, hangar (facility), arctic version, as well as in an easily assemblable shelter or on an open frame.
FUNCTIONAL OPPORTUNITIES OF GAS TREATMENT EQUIPMENT
The priority purpose of the ENERGAS gas treatment equipment is filtration and gas metering. At the same time, existing systems and units are equipped with additional assemblies and elements that significantly expand the functionality of the main equipment and increase the efficiency of process procedures.
Filtration system
A gas treatment unit typically includes two filtration lines with a throughput of 100% flow, or three lines with a throughput of 50% of the flow each.
Gas filters in each specific case are selected depending on the gas composition, the amount of mechanical impurities and liquid fractions in gas fed to the facility.
For the most part, gas filters of two-stage purification with replaceable filter elements (cartridges) are used in ENERGAS gas treatment equipment. Such filters provide a high degree of removal of droplet liquid and mechanical impurities at the designed pressure drop. At the filter inlet, the largest and heaviest particles settle to the bottom. Then gas passes through two stages of filter elements, which hold even the smallest particles, so that gas enters the upper part of the filter already pure. This method of filtration allows you to change the type of filter elements or a combination thereof to optimize the purification efficiency when the composition and characteristics of the incoming gas change.
In the case of high gas humidity there are used filters with a vortex lattice at the first stage of filtration and subsequent final purification by filter elements. The passage of the gas flow through the vortex lattice of the first stage of the filter creates vortices, causes flow interruption and a consequent reduction and increase of gas pressure. Due to this condensation of liquid impurities of gas takes place. High efficiency of gas purification is achieved by using own gas condensate as an absorbent.
In most cases, the purification efficiency is 100% for solid particles of at least 3 microns and droplet liquid of at least 5 microns. For particles ranging in size from 0.5 to 3 microns, the efficiency is about 99%.
Filters are equipped with sensors and indicators for monitoring pressure, differential pressure, gas condensate level, and blow-off & discharge pipelines with safety valves. The purgings from the filter-separator storage tanks are throwing automatically off to the drainage tank. The level of gas condensate in the filters and in the external storage tank is set and maintained at a given value by the automatic control system of the gas treatment unit.
For quick access to the filter elements, cleaning or replacing them, a shelter cover is provided above the filters with the service area and the hoists to remove the upper end caps of the filters.
Systems of separation and dehydration
At the treatment of associated petroleum gas, the separator- slugcatcher is often included in the equipment, which performs intake of peak liquid blowout and the smoothing of pulsations of gas mixture.
Additionally, an adsorption dryer can be installed. This is necessary in the event that the capacity of the system is not sufficient to achieve the design set gas parameters by humidity.
Gas metering unit
After purification and drying, gas enters the metering unit, which can include one or two measuring lines with a 100% flow capacity and a bypass line (in the case of one measuring line or on customer's request). According to special requirements, the gas metering unit can additionally be equipped with a low-flow line.
Commercial or process gas metering is carried out by measuring the volume and volume flow of gas under operating conditions and automatically bringing the measured volume to standard conditions, depending on the pressure, temperature and gas compressibility factor.
Primarily there are used turbine and ultrasonic primary flow transmitters (flowmeters). Rotary, vortex, diaphragm, Coriolis or thermoanemometric flowmeters can also be used. The data from the converters come to the corrector-calculators (flowcomputers).
Gas metering system performs the following functions:
- The registration of the volume values measured by the flowmeters for each measuring line;
- Measurement of temperature and absolute gas pressure for each measuring line;
- Computation of gas compressibility factor;
- Computation of the correction factor and gas volume under standard conditions;
- Computation of the volumetric flow rate of gas under operating and standard conditions;
- Indication of measured and calculated physical values on each line on liquid crystal displays of gas volume correctors;
- Transfer of measured and calculated data from correctors to the control system of the gas treatment unit and, if necessary, to other monitoring systems;
- Processing of alarms and their retransmission to the control system of the gas treatment unit and, if necessary, to other monitoring systems;
- Maintenance of the archive database of measured values of gas volume and event log.
Gas heating unit
To achieve the design gas temperature, a heating unit is included in the gas treatment equipment. It can be heaters with an intermediate heat medium (in the presence of an external heat source) or electric heaters. Units of ENERGAS can also be equipped with own block-modular boilers.
For a smooth power adjustment (or blocking the heating in emergency situations), scope of supply includes a control cabinet equipped with an interface for communication with an external APCS.
Reduction system
If gas pressure in the supply pipeline is higher than that required for the correct operation of the gas-using plants, the gas treatment equipment is completed with a gas pressure reduction unit.
The structure of the ENERGAS plant may include a multi-line reduction system. This is necessary for parallel supply of fuel gas (with differing pressure parameters) of a number of facilities on one production site.
Metering and analytical equipment
According to special design requirements of the customer, the process flow diagram incorporates equipment for metering and analyzing various gas parameters.
For example, on-stream chromatograph with a sampling device for determining the composition and calorific value of a gas (calorimeter). The calorimeter determines the component composition of gas and calculates the heat of combustion, density, relative density and Wobbe index.
To meter water dew-point temperature and hydrocarbon dew-point temperature of gas, a suitable system with a sampling device is included in the gas treatment unit.
CONTROL AND SAFETY SYSTEMS OF GAS TREATMENT EQUIPMENT
In addition to life support systems (lighting, heating, ventilation), the ENERGAS units are necessarily equipped with safety systems: fire and gas detection, alarms, fire extinguishing systems.
At treatment a low-pressure associated gas (with a pressure close to vacuum), an oxygen detection system is also installed - with a special oxygen monitoring sensor in the gas stream.
Gas treatment units are fully automated and do not require additional manual adjustment for debugging the correct interaction of various equipment systems.
The control system implements preparation for start, start-up, shutdown and maintaining the optimum operating mode of the unit; it controls process parameters; it provides automatic protection and signaling; it processes the parameters of the workflow and emergency events with the issuance of information by standard data exchange protocol.
For large-scale gas treatment projects, the ENERGAS Group supplies two-level ACS of gas facilities (ACS GF) or ACS of gas supply (ACS GS).
The lower level is the local ACS of the main equipment included to the system of complex gas treatment, and relay panels of automation of auxiliary equipment. The upper level is a switch for information exchange, an automated workstation with server functions, a control cabinet, an automated operator workstation, an emergency shutdown console.
ACS GF and ACS GS are equipped with individually developed software, and information transfer is carried out using modern communication channels and protocols.
EXAMPLES OF PROJECTS IMPLEMENTATION
Examples of gas treatment and gas supply projects implemented by the ENERGAS Group in the oil and gas sector, the power industry and other industries give a good idea of the process features and production capabilities of the equipment presented.
Associated gas treatment unit for power supply complex “Usa” (LLC “LUKOIL-Komi”)
At Usinskoye oil field there is operating a power supply complex with an installed electric capacity of 100 MW and a heat output of 152.1 Gcal / h. The generating equipment includes 5 power units GTPP-25PA produced by JSC "UEC-Aviadvigatel", each of which is made on the basis of gas turbine unit GTE-25PA with a capacity of 25 MW.
The main and reserve fuel for the power supply complex is associated petroleum gas. Its treatment and feed to the turbines of GTU-CHPP is carried out by the multifunctional gas-treatment system of ENERGAS, which includes three compressor units and an associated gas treatment unit (AGTU).
The AGTU performs flow metering and gas filtration, it is equipped with a bilinear metering unit, a separator - slugcatcher and a filtration system. The degree of gas purification is 100% for the liquid fraction and 99.8% for solid particles larger than 10 μm.
Additional functionality – fuel handling for a boiler house of own needs. With this purpose AGTU is equipped with a gas heating unit and a reduction system. Capacity of AGTU is 2 260 ... 21 684 kg / h (2 430 ... 24 059 m3 / h).
Packaged gas treatment unit for CCGT unit – 190 Novomoskovskaya GRES (PJSC “Quadra”)
At Novomoskovskaya GRES, a combined cycle gas turbine unit with capacity of 190 MW is operating. The power unit is based on the following: General Electric gas turbine unit of type Frame 9E, Siemens SST PAC 600 steam turbine unit and waste heat boiler.
Fuel treatment for the CCGT unit is performed by a packaged gas treatment unit (PGTU) of ENERGAS GS-FME-5000/12. This is a complete process unit with maximum integration of elements on a single frame. PGTU is equipped with three lines of gas filtration, gas metering station, a system for measuring the temperature of dew point on water and hydrocarbons with a sampling device.
Capacity of PGTU is 60,000 m3 / h. After preliminary treatment, gas flow is transferred to the booster compressor station, which was also supplied and commissioned by the ENERGAS Group.
Treatment system of fuel and starting gas for BCS “Alan”(NHC “Uzbekneftegaz”)
A booster compressor station for natural gas transportation consisting of two gas-compressor units GPA-16 "Volga" (KMPO) was built in the Alan field in Uzbekistan. BCS is equipped with the fuel and start-up gas treatment of ENERGAS.
The GS-FHP-400/56 fuel and start gas treatment system (FSGTS) is a multifunctional unit for purification, heating and reducing gas. It consists of: coalescing separator filters (gas filtration degree - 99.98%), automatic condensate drainage system, electric heaters, two-line reduction units for start and fuel gas.
The gas treatment system is placed on an open frame. Assigned resource (service life) FSGTS is 25 years. The project was implemented in the shortest possible time - design, production, factory testing and delivery were completed in 2 months.
Erection supervision works, as well as consulting and technical support of the project, were performed by the experts of LLC ServicENERGAS.
System of integrated associated gas treatment at Zapadno-Mogutlorskoye field
At the Main Pumping Station (MPS) of Zapadno-Mogutlorskoye oil field of “Aganneftegasgeology” there is operating an associated gas treatment system supplied by the company ENERGAS. This is a process complex that includes a screw type booster compressor unit, an adsorption gas drier, a refrigerating unit (chiller), a gas metering unit with flow meters.
The specialists of the ENERGAS Group developed this project on the basis of the engineering solution, which allows, when compressing APG, to reach the negative dew point temperature on water (-20 ° С). Another feature is that the drying of associated gas is carried out by two methods: refrigerated and adsorption.
All equipment is located on a single site, placed in separate all-weather shelters (arctic design), the operating mode as a part of MPS is continuous. APG treatment system consistently performs drying, fine filtration, compression up to 3 MPa, volume metering, cooling and injection of associated gas into the transport pipeline.
System for integrated natural gas treatment for Gas reciprocating power plant (GRPP) of microelectronics plant (JSC "Angstrem-T")
The research and production complex of JSC “Angstrem-T” is equipped with an autonomous power supply center - Gas reciprocating power plant (GRPP) with an electric capacity of 36 MW.
GRPP consisting of five gas reciprocating units (GRU) Wartsila 16V34DF operates on trigeneration cycle and provides the enterprise with the necessary amounts of electricity, heat and cold. There is also a new boiler room on the basis of 4 water-heating boilers Buderus.
The fuel for GRPP and the boiler room is fed through the system for integrated treatment of fuel (natural) gas, which consistently performs pre-filtration, flow metering, fine purification and compression of gas.
The equipment package includes a unit of input gas filters, gas metering station, separation system, booster compressor station (in 2 compressor units). The construction and commissioning of the gas treatment system was carried out by specialists of the ENERGAS Group.
ACS of gas feeding for power supply complex "Yarega" (LLC “LUKOIL-Komi”)
At the Yaregskoye oil-titanium field, auxiliaries power supply complex is being built on the basis of GTU-CHPP. The installed electric power of the GTU-CHPP is 75 MW, the thermal power is 79.5 Gcal / h. Fuel for the power complex "Yarega" is natural gas of Kurino-Patrakovskoye gas condensate field.
The necessary gas quality with design parameters for purity, temperature and pressure will be ensured by the gas treatment and gas supply system of ENERGAS consisting of: gas treatment packaged unit, booster compressor station of 4 units, gas feeding motor operated valves.
The full two-level automatic control system - gas supply ACS - provides control, regulation and safe operation of this process equipment.
ACS GS is integrated into the APCS of the power complex. Internal and external connections are made using Ethernet and S7-connection and Profibus protocols.
A multimodal unit of gas treatment for the facilities of gas and condensate processing plant of East Urengoy licensed area (Rospan International JSC)
In the field of gas treatment and compression, ENERGAS has gained experience in performing complex, large-scale projects, including the production and commissioning of multi-module (multipackaged) gas treatment units.
Such units are characterized by high productivity - the flow rate of treated gas, and consist of several (up to ten) isolated block-boxes that, when mounted, are joined together in a single block building with a common roof.
They are used on large generating facilities with large-capacity gas turbines, as well as at oil and gas production sites, where it is necessary to provide in parallel and continuously high-quality gas (with different parameters) several main and auxiliary facilities.
For example, at East Urengoy licensed area of “Rospan International” JSC (Oil company “Rosneft”), the multi-module fuel gas treatment unit of ENERGAS is designed to feed gas to all consumers of gas and condensate processing plant, namely: a gas turbine power plant, a boiler house, low-temperature separation units, methanol regeneration units, Intake flow line unit, booster compressor station of low-pressure gases, flare unit and other facilities.
Thanks to the stable partnership and cooperation relations in its segment of process equipment, the ENERGAS Group is on the path of further professional improvement and the development of unique engineering experience - as a cohesive team of specialists full of energy and confidence in their capabilities to create new efficient projects for integrated gas treatment.