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Presentation

HMS Group Pumping Systems for Oil Transportation Pipelines

Nikolay Yamburenko. Member of the Russian Academy of Engineering. Deputy General Director. HMS GROUP MANAGEMENT COMPANY LLC

Igor Tverdokhleb. Ph.D., Director of R&D. HMS GROUP MANAGEMENT COMPANY LLC

Grygoriy Vizenkov. Engineer, Head of scientific and technical coordination department in R&D. HMS GROUP MANAGEMENT COMPANY LLC

"… arrange special pipes from oil wells to factory and further to the sea shore to supply oil both to factory and sea vessels” – this thought by Dmitri Mendeleev, published back in 1863, can be apparently considered as an inception point of creating the pipeline transportation system for oil and petroleum products in Russia.

It is also necessary to mention a contribution to foundation and development of the oil pipelines in Russia and the CIS made by the pump manufacturing companies that are currently integrated into HMS Group - a machine-building and engineering holding company. In the 60s of the last century they designed a wide range of pumps for oil and petroleum products transportation: NM trunk pumps, NPV and NMP series of vertical and horizontal booster pumps, NOU series of leaks removal pumps and others. Those pump series are still successfully operated at the major trunk pipelines.

An important milestone of designing a high-efficient pipeline pumping equipment was development of the new pumping systems for the Eastern Siberia - Pacific Ocean oil pipeline (ESPO-1 and ESPO-2 project stages) operated by Transneft. It was a complex technical and organizational challenge: it is enough to say the pipeline pressure reaches 100 bar that respectively requires increased power of the pumping systems drives up to 12 MW and adjustment of the pipeline performance by changing the pumps rotation speed.

The integrated project management with comprehensive control was implemented by a single center - HMS Group project team. The leading Russian and foreign manufacturers also participated in the project: Voith Turbo, Siemens, EagleBurgmann, ELSIB, VNIIAEN (HMS Group), Nasosenergomash (HMS Group) and others.

The tasks have been effectively accomplished by using the modern software platforms integrating the products data management tools, 3D solid-state modeling, finite element analysis, computational fluid dynamics, and automated development of the technical documentation: PDM Search, ERP, Solidworks, Pumplinx, Ansys, Techcard, PowerMill.

The pumping equipment by HMS Group integrates both well-known classical solutions and the new ones obtained as a result of the previous 50 years of R&D works. Figure 1 shows the qualitative influence of individual geometric parameters of the structural elements on the main characteristics of the pump. These data, being considered at the early development stages, allows creating the optimal design of products and achieving maximum efficiency and reliability. For this purpose the software tools are applied in a combination with various corporate standards, methods and programs.

Fig. 1

One of the key indicators showing the pumping equipment technical level is its energy efficiency, which is mainly determined by efficiency of the flow part (diffuser). Therefore the main task was the anticipatory development of appropriate flow parts based on experimental research and contemporary CFD methods (Fig. 2). At the moment the HMS Group's companies have accumulated a base of the flow parts (inlets, the first and intermediate stages, screw-centrifugal inducers, outlets) for a specific speed range NS = 30-300.

Fig.2

Energy efficiency became a very important issue within the last years. It is known that Europump has developed an indicator of the minimum efficiency index (MEI) for pumps. At the same time, the Department of Energy of the USA has offered a special integrated index obliging both the pump manufacturers and operators of hydraulic systems to reduce the energy consumption. It is assumed there should be a single comprehensive indicator for the whole hydraulic system, rather than a separate one for a pump only (as in Europe) since those two indicators may conflict with each other. Therefore the Hydraulic Institute (HI), the largest association of pump industry manufacturers in North America, has established several committees to work on the problem. There is no any final decision has been made yet on the comprehensive indicator although a PER value is being actively discussed. A PER value represents a kind of average power consumed by a pump at 25%, 50%, 75%, 100% of its capacity.

Also HI works closely with the American National Standards Institute (ANSI). Since many standards developed by HI are the national ANSI/HI standards it serves as a driving force for competing companies to work actively with HI on introduction of a single comprehensive indicator for a whole hydraulic system.

The problem of energy saving, of course, is relevant, extremely difficult and requiring a combination of intellectual and financial resources of many participants dealing with it. As regards to the ESPO-1 and ESPO-2 oil pipeline systems, the problem of energy saving is practically solved, first of all, due to the numerical studies and experimental testing of the pumps flow parts and introduction of replaceable flow parts allowing to achieve the highest possible efficiency in all planned operation modes of the pipeline. Theoretical background and verification on the full-scale pumps show that efficiency increase of the pumps with replaceable flow parts in comparison with the rated flow parts makes the following figures (see Fig. 3):

Fig. 3

Reliability of developed equipment is based on numerical and experimental researches to define the main factors influencing on the design functionality:

• Hydraulic radial forces applied to the rotor with various flow diversion devices.
• Axial forces applied to the rotor and balancing devices.
• Rotor dynamic properties, including analysis of the own frequencies and torsion oscillations.
• Calculation of the temperature fields and thermal stress applied to the pump parts and components including thermal shock.
• Calculation and testing of the trust and radial bearings of a friction type (including test of their operation in the pumped media), mechanical seals and disk couplings.

The products quality is ensured by the up-to-date manufacturing technologies in a combination with the state-of-the-art equipment: machine tools and processing centers by SCHIESS, DOOSAN, DEMAG, SCHENK, SODIK (Fig. 4).

Fig. 4

To confirm feasibility and expected performance of pumps by HMS Group a unique testing facility has been constructed to perform full rotation speed tests in all  required operating conditions including emergency ones (Fig. 5). The facility is equipped with standard systems and components: electric motors, booster pumps, pump rotor speed control devices (VFD or hydraulic couplings), cooling and lubrication systems, environment conditions simulation systems, volume compensation systems, mechanical seals locking systems, etc.

Here are the main technical data of the testing facility:

• Electric drive power: 25 MVA
• Electric voltage: 10 kW
• Total facility area: 3,000 square meters

Fig. 5

Application of the modern scientific and project-based approach in a combination with the integrated project management resulted in creation of the following successfully operated pumping systems (Fig. 6):

• Trunk pumps of NM series — with capacity (Q) up to 12000 m³/h; drive power (Р) up to 12 MW; equipped with a variable frequency drive (ESPO oil pipeline, stage 1).
•  
• Trunk pumps of NM series — with capacity (Q) up to 9150 m³/h; drive power (Р) up to 8 MW; equipped with hydraulic couplings (ESPO oil pipeline, stage 2).
•  
•          Trunk pumps of NM series — with capacity (Q) up to 7500 m³/h; drive power (Р) up to 5.5 MW; equipped with a variable frequency drive (Purpe-Samotlor oil pipeline).
•  
• Horizontal booster pumps of NGPN-M series — with capacity (Q) up to 4000 m³/h; drive power (P) up to 1.6 MW (Ust-Luga oil pipeline).

Fig. 6

The pumps efficiency level corresponds to the highest attainable one in the world while quality and reliability of the pumping systems have been significantly increased: mean time between failures makes 40,000 hours, operational lifetime makes 63,000 hours, and service life is 40 years. In order to achieve the required operation parameters and efficiency at different stages of the pipeline development the pumps were equipped with replaceable flow parts while the booster pumps obtained the screw-centrifugal type inducers for a high suction ability. 

The field test results and technology level achieved during development of the pumping units together with accumulated knowledge and experience demonstrate that potential of the further improving the pumping systems is far from being exhausted. Previously, the original cost of product was considered as a major determining factor during development while the product life cycle cost was not taken into consideration. This circumstance led to creation of products with minimal weight and dimensions but with higher rotation speed than optimum one (Fig. 7).

Fig. 7

Such decisions, of course, lead to a certain decrease of efficiency and cavitation properties of designed pumps. Thus, the analysis of the trunk pumps NM 10000-210, which has been operated for many years on existing pipelines, showed their efficiency and cavitation properties could be improved if pump was designed for operation with optimum rotation speed, and in this particular case lower rotation speed was required. In addition, better cavitation properties increase admissible pressure drop between adjacent pumping stations and thereby the performance of existing pipelines as well or increase the distance between pumping stations for the newly constructed pipelines.

At the same time reduction of the pumps rotation speed is caused by increase of their overall weight and dimensions, application of multipliers or special motors with variable speed drives, large dimensions and weight of the pumping systems foundations. Therefore, when selecting a pump and particularly when selecting its rotation speed it is necessary to consider all the factors influencing on the equipment life cycle cost. As for example of the NM 10000-210 series pump, the evaluation of its life cycle cost shows that pump with lower rotation speed is preferable.

However, it will be wrong to say this conclusion is also valid for pumps with different combination of parameters. In particular, calculation of the lifecycle cost for a pumping unit with 12000 m³/h capacity and 380 m head for ESPO pipeline, taking into account all the factors mentioned above, demonstrated the rotation speed (set in the project) of 3000 rpm (nq=46) is optimal. Since the cavitation properties have a significant impact on the product life cycle cost, they can be improved by the other technical solutions, for example, by application of inducing impellers (screws). This solution has been repeatedly tested at existing pipelines, particularly at the NM series of the oil trunk pumps.

But this is a process of the further improvement of pumping and piping systems in general. Scientific and engineering centers of HMS Group work systematically in these directions.

References:

1. Igor Tverdohleb, Grigory Vizenkov, Alexander Biryukov. Oil pipeline from Siberia to the sea. WORLD PUMPS, May 2012.

2. Aleksandr Birukov, Elena Knyazeva, Andrew Rudenko, Igor Tverdokhleb, L. Bakker. The methods the trunk pumps efficient operation at variable operation modes of the oil pipeline. Science and technology of the pipeline transport of oil and petroleum products. №4 (12), 2013.

3. Aleksandr Birukov, Elena Knyazeva, Arkady Ivanyushin, Andrew Rudenko, Igor Tverdokhleb. Increasing pump performance. Pump Engineer. №9, 2012, р.36–39.

4. H.H. Anderson, Efficiency majoration formula for fluid machines, 1970.

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