Compressor Station Fuel Gas Superheating Using Lube Oil Waste Heat

Author(s):  
Katie T. Sell ◽  
Paul R. Langston ◽  
Rene´ H. Mitchell

Compressor station gas turbine engines require protection from fuel gas liquid drop-out caused by the Joule-Thomson effect when natural gas is let down from transportation line pressure to the burner supply pressure. Indeed, gas turbine manufacturers specify a minimum gas superheat, which requires fuel gas heating at pipeline temperatures experienced in Northern Europe. Conventionally, fuel gas superheating is achieved through the use of either electric or gas fired water bath heaters, which require maintenance, and an external heat source. Meanwhile, waste heat from the turbo-compressor lube oil system is released to atmosphere, typically by air-cooled heat exchangers. Hence, there is an obvious opportunity to protect the gas turbine engine, whilst reducing the amount of heat rejected to the environment. Mechanical integrity is a key operational requirement when combining fuel gas superheating with lube oil cooling in a single heat exchanger. Fuel gas at high pressure must not enter the low pressure lube oil system. High integrity Printed Circuit Heat Exchangers (PCHEs) are ideally suited to this application, as they are diffusion bonded and fully welded heat exchangers. Used extensively in offshore high pressure gas compression trains in the North Sea, PCHEs have demonstrated that they are low maintenance items that are ideal for use in remote unmanned applications, such as those required by gas compression stations. PCHEs are highly compact, reducing space and structural requirements. This allows the exchanger to be installed underneath the compressor, minimizing the visual impact of the heat exchanger. In addition, safety and pressure relief requirements are significantly reduced, a PCHEs do not have a failure mode analogous to tube rupture in shell and tube heat exchangers. National Grid Transco have realized the opportunities of PCHEs and operated them successfully over many years in many of their compression stations throughout the United Kingdom.

Author(s):  
C. F. McDonald

Increased emphasis is being placed on the regenerative gas turbine cycle, and the utilization of waste heat recovery systems, for improved thermal efficiency. For such systems there are modes of engine operation, where it is possible for a metal fire to occur in the exhaust heat exchanger. This paper is intended as an introduction to the subject, more from an engineering, than metallurgical standpoint, and includes a description of a series of simple tests to acquire an understanding of the problem for a particular application. Some engine operational procedures, and design features, aimed at minimizing the costly and dangerous occurrence of gas turbine heat exchanger fires, are briefly mentioned.


Author(s):  
Dereje Shiferaw ◽  
Robert Broad

The purpose of this paper is to show how compact heat exchanger technology can offer energy savings and hence cycle efficiency improvements on new and existing gas turbine installations by being utilised for fuel gas heating. After a brief introduction to high temperature compact heat exchanger technology and comparison to traditional equipment, thermodynamic cycle analysis for a combined cycle gas turbine plant (CCGT) is used show the advantages of compact technology over conventional technology, analysing the fuel gas heating, to illustrate the overall savings. A case study is used to demonstrate an increase in net LHV electric efficiency in the range of 0.5 to 1.17 % achievable using high effectiveness compact diffusion bonded heat exchangers in fuel gas heating. Intermediate pressure and high pressure feed water heating is considered for increasing the fuel gas inlet temperature to the combustor. The model is built in Excel and is extended to a capital expenditure overview based on new or a retrofitting in existing plants.


Author(s):  
J. M. Overli ◽  
R. Magnusson

This paper describes the results obtained from a study commissioned to ascertain the optimum drive arrangements for the gas compression machinery to be installed on an integrated platform in the North Sea. The study was restricted to two main drive type alternatives: - All compressor stages on one shaft driven by a variable speed aero-derivative gas turbine. - All compressor stages with separate, constant speed, electric motor drives. The study took into account drive option and shafting arrangements with regard to flexibility of operation, weight, area, lay-out, foundation/alignment, waste heat recovery requirements, availability/reliability, safety, maintenance, fuel consumption, investment cost and operational experience. For the specific case studied, the overall conclusion was in favour of the gas turbine drive alternative.


Author(s):  
Sergey N. Movchan ◽  
Vyacheslav V. Romanov ◽  
Volodymyr N. Chobenko ◽  
Anatoliy P. Shevtsov

The recovery of exhaust gas heat in waste-heat recovery boilers (WHRBs), and the injection of superheated steam into gas turbine combustors form the basis for the development of “Aquarius” type gas turbine units. In November 2003 the first commercial “Aquarius-16” unit with 16 MW power output that was designed and built by Ukrainian specialists was put into operation at “Stavishchenskaya” gas compression station for the “Progress” gas pipeline. The efficiency of the unit is 42.1% at turbine inlet temperature (TIT) of 1358K. To date the unit has accumulated more than 9,500 hours and has saved about 13.5 million m3 of fuel gas compared to units having a similar power output operating in simple cycle configuration. The emission levels, corrected to 15% O2 (by volume) are for NOx, 40–68 mg/Nm3, and CO, 58-10 mg/Nm3. The temperature of gases discharged into atmosphere is not more than 45°C. These figures on efficiency and emission levels, although very good, still leave scope for improvement. The purpose of the paper presented here is to define the development methodology to allow the “AQUARIUS” units to achieve efficiencies of 50% and higher. It is shown that development of “AQUARIUS” units with efficiency of about 50% will require operating at maximum cycle temperature around 1673 K and pressure ratio of 25–35. Further development of the Aquarius units with water injection at the low-pressure compressor inlet, the use of more efficient cooling of the engine gas path components and additional recovery of exhaust gas heat by means of fuel will need to operate at maximum cycle temperatures around 1873 K and pressure ratio of 45–50 in order to generate efficiencies more than 50%.


Author(s):  
H. Zabiri ◽  
V. R. Radhakrishnan ◽  
M. Ramasamy ◽  
N. M. Ramli ◽  
V. Do Thanh ◽  
...  

The Crude Preheat Train (CPT) is a set of large heat exchangers which recover the waste heat from product streams back to preheat the crude oil. The overall heat transfer coefficient in these heat exchangers may be significantly reduced due to fouling. One of the major impacts of fouling in CPT operation is the reduced heat transfer efficiency. The objective of this paper is to develop a predictive model using statistical methods which can a priori predict the rate of the fouling and the decrease in heat transfer efficiency in a heat exchanger in a crude preheat train. This predictive model will then be integrated into a preventive maintenance diagnostic tool to plan the cleaning of the heat exchanger to remove the fouling and bring back the heat exchanger efficiency to their peak values. The fouling model was developed using historical plant operating data and is based on Neural Network. Results show that the predictive model is able to predict the shell and tube outlet temperatures with excellent accuracy, where the Root Mean Square Error (RMSE) obtained is less than 1%, correlation coefficient R2 of approximately 0.98 and Correct Directional Change (CDC) values of more than 90%. A preliminary case study shows promising indication that the predictive model may be integrated into a preventive maintenance scheduling for the heat exchanger cleaning.


2009 ◽  
Vol 13 (4) ◽  
pp. 41-48
Author(s):  
Zheshu Ma ◽  
Zhenhuan Zhu

Indirectly or externally-fired gas-turbines (IFGT or EFGT) are novel technology under development for small and medium scale combined power and heat supplies in combination with micro gas turbine technologies mainly for the utilization of the waste heat from the turbine in a recuperative process and the possibility of burning biomass or 'dirty' fuel by employing a high temperature heat exchanger to avoid the combustion gases passing through the turbine. In this paper, by assuming that all fluid friction losses in the compressor and turbine are quantified by a corresponding isentropic efficiency and all global irreversibilities in the high temperature heat exchanger are taken into account by an effective efficiency, a one dimensional model including power output and cycle efficiency formulation is derived for a class of real IFGT cycles. To illustrate and analyze the effect of operational parameters on IFGT efficiency, detailed numerical analysis and figures are produced. The results summarized by figures show that IFGT cycles are most efficient under low compression ratio ranges (3.0-6.0) and fit for low power output circumstances integrating with micro gas turbine technology. The model derived can be used to analyze and forecast performance of real IFGT configurations.


1978 ◽  
Author(s):  
C. F. McDonald

With soaring fuel costs and diminishing clean fuel availability, the efficiency of the industrial gas turbine must be improved by utilizing the exhaust waste heat by either incorporating a recuperator or by co-generation, or both. In the future, gas turbines for power generation should be capable of operation on fuels hitherto not exploited in this prime-mover, i.e., coal and nuclear fuel. The recuperative gas turbine can be used for open-cycle, indirect cycle, and closed-cycle applications, the latter now receiving renewed attention because of its adaptability to both fossil (coal) and nuclear (high temperature gas-cooled reactor) heat sources. All of these prime-movers require a viable high temperature heat exchanger for high plant efficiency. In this paper, emphasis is placed on the increasingly important role of the recuperator and the complete spectrum of recuperative gas turbine applications is surveyed, from lightweight propulsion engines, through vehicular and industrial prime-movers, to the large utility size nuclear closed-cycle gas turbine. For each application, the appropriate design criteria, types of recuperator construction (plate-fin or tubular etc.), and heat exchanger material (metal or ceramic) are briefly discussed.


2001 ◽  
Author(s):  
Arash Saidi ◽  
Daniel Eriksson ◽  
Bengt Sundén

Abstract This paper presents a discussion and comparison of some heat exchanger types readily applicable to use as intercoolers in gas turbine systems. The present study concerns a heat duty of the intercooler for a gas turbine of around 17 MW power output. Four different types of air-water heat exchangers are considered. This selection is motivated because of the practical aspects of the problem. Each configuration is discussed and explained, regarding advantages and disadvantages. The available literature on the pressure drop and heat transfer correlations is used to determine the thermal-hydraulic performance of the various heat exchangers. Then a comparison of the intercooler core volume, weight, pressure drop is presented.


2018 ◽  
Vol 225 ◽  
pp. 05006 ◽  
Author(s):  
Shaymaa H. Abdulmalek ◽  
Hussain H. Al-Kayiem ◽  
Aklilu T. Baheta ◽  
Ali A. Gitan

Heat recovering from biogas waste energy requires robust heat exchanger design. This paper presents the design of fuel gas-air heat exchanger (FGAHE) for recovering waste heat from biogas burning to regenerate desiccant material. Mathematical model was built to design the FGAHE based on logarithmic mean temperature difference (LMTD) and staggered tube bank heat transfer correlations. MATLAB code was developed to solve the algorithm based on overall heat transfer coefficient iteration technique. The effect on tube diameter on design and thermal characteristics of FGAHE is investigated. The results revealed that the smaller tube diameter leads to smaller heat transfer area and tube. On the other hand, the overall heat transfer coefficient and Nusselt numbers have larger rates at smaller tube diameter. In conclusion, the nominated tube diameter for FGAHE is the smaller diameter of 0.0127 m due to the high thermal performance.


2018 ◽  
Vol 58 (2) ◽  
pp. 719
Author(s):  
Lourens Jacobs ◽  
Nancy Nguyen ◽  
Ryan Beccarelli

Woodside is an Australian oil and gas company and a leading global operator of offshore gas platforms and onshore LNG processing facilities. It is a public company listed on the Australian Securities Exchange headquartered in Perth, Western Australia. Woodside operates the Goodwyn A gas platform on behalf of the North West Shelf (NWS) Project. Woodside assessed Li-ion battery technology and considered the technology mature and ready to be utilised on offshore and onshore operating assets. Woodside operates dedicated islanded gas turbine power generation at each of its onshore and offshore facilities. It was concluded that a large battery energy storage solution (BESS) can deliver several advantages if connected to such an islanded power generation system. The most significant benefit materialises by using a BESS as backup (or spinning reserve) for the gas turbine generators (GTGs). Woodside decided to pioneer the Li-ion BESS technology in a first of its kind application on the NWS Project offshore Goodwyn A gas platform. The Goodwyn A BESS is designed for a 1 MW power and 1 MWh energy capacity, which is considered sufficient to provide the spinning reserve for the Goodwyn A platform. Currently, Goodwyn A operates four 3.2 MW GTGs to provide a typical load of 7–8 MW, with one GTG providing the N+1 spinning reserve. When the BESS is connected to the power generation system, Goodwyn A will operate three GTGs, with the BESS proving the backup in case one of the GTGs trip. The BESS will provide the full 1 MW for a minimum of 1 h, which will give the operators enough time to start the standby GTG or adjust the facility loads (load shedding). The result will be a decrease in overall fuel gas consumption (due to better efficiencies on the remaining GTGs in operation) and a related reduction in CO2 emissions. The project supports the overall objective of the North West Shelf Project to improve the energy intensity of its facilities by 5% by 2020. Woodside believes that developing capability and experience on the installation of BESSs, using Goodwyn A as an early adopter, will facilitate similar and larger installations on other Woodside operated offshore and onshore assets. This is one of the technologies Woodside believes will play an important role to ensure a lower carbon future globally.


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