Operation Optimization Of Long-Distance Natural Gas Transmission Pipelines And Compressor Stations Load Scheduling

With the progressive growing demand for high-quality clean energy and fuel, such as natural gas, and the exploitation and development of large quantities of gas field far from the center, quiet great progress has been made in the engineering techniques' level of natural gas long-distance transmission. Pipeline network transmission system gradually becomes more complicated. On the one hand, it is more difficult to understand and grasp the operation law of the pipeline system, to analyze and deal with the accident-operating of the pipeline system, to prove and put forward the rational operation scheme. On the other hand, the production, supply and sell of natural gas directly are influenced by operation conditions of the pipeline systems, so, according to the flow law of the gas in the pipe network of natural gas, to find out mutual influence and flowing relation among each parameter in the pipe network, to make its rational scheduling and reliable running, are facing research workers. How to realize the safe operation, low consumption, energy-conservation and improvement of the system's economic benefits, is a concern of scientific research and management for operation. Operation optimization of natural gas pipeline (different from that of design optimization) becomes the urgent issue for the operator's close attention. It is also the inevitable outcome of market economic development.Because of such a background, this dissertation is devoted to the investigation of operation optimization of natural gas long-distance transmission pipeline and the load scheduling and assignment within compressor station.First of all, after the general operational scheduling question is introduced, general train of thought, scheduling method and solution of optimizing the long-distance transportation pipeline is also put forward. This is the first innovation of the thesis. This part establishes the theoretical foundation on the unified decision and management during whole process of operating the long-distance transmission pipeline, as well as the optimization of scheduling-load on the compressor station in chapter seven. Considering the type-selection of compressor when the load is scheduled, the optimization issue of type-selection is singly studied and discussed in chapter four.Secondly, transportation pipeline and compressor both have their own working characteristics, and also can unit. So the introduction and the analysis of this recommend essential rudimentary knowledge for the optimal operation of natural gas pipeline in the following chapter five and six.As one of the main content, models of the steady-state operation optimizationof natural gas pipelines network are discussed in chapter five. Steady-state operation optimization models, which are extensively adopted at present, are introduced and analyzed in this chapter. And then a new-type operation optimization model with more practicality is exployed. Such complicated factors as bypassing a compressor station, and the electricity/gas price factor(considering compressor is driven by electric power or gas turbines powered by pipe-transported natural gas), is taken consideration in this model. Meanwhile, a kind of new treatment method with complicated pipe segments constraints is firstly brought forward. The structurized ideology is embodied in the treatment method. Nesting of each and type objection subdividing are its core. This is the second innovation of the thesis.Issue of unsteady-state operation optimization of long-distance transmission pipeline is investigated in Chapter six; this part is the second main content of thesis. With the combination of the unsteady flowing regular with fluid properties of natural gas, unsteady-state flowing partial differential equation of natural gas long-distance transmission pipeline; the equation is a typical parabolic equation. Moreover, solving algorithm of parabolic is study in detail. And then in the light of the systematic characteristic of transportation pipeline, objective function of unsteady-state operation optimization has been established; under unsteady-state operation its constraint condition has been also analyzed. In the end of this part, to optimize the mathematics model to the unsteady-state, hierarchical optimization is introduced into the model, which is more used in water electric department. Furthermore the solution and its process are discussed in detail. This is one of key content, and the third innovation of this thesis, too.Chapter seven is another one of main content, optimal scheduling of load on the compressor station is investigated. Firstly working condition of long-distance transmission pipeline is discussed, and then two concepts" supreme pressure principle "and " best operation area "are introduced,through which optimizing the assignment of the whole pipeline pressure is completed. The fourth innovation of the thesis is to explain and analyze the optimal load scheduling in two-level optimization algorithm. In addition, the case study in the long-distance transportation pipeline is provided, which are underway and will be put into in an all-round way operating soon. The result of calculation indicates: the adoption of the optimal model to schedule the load can obviously thrift the operating cost of pipeline operation, therefore it has verified this model exact and practicable.