Optimal Design of Natural Gas Gathering Systems
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problem, this method finally defines that only one pipeline can be chosen in candidate
pipelines starts from the same node.
3 Problem Description and Mathematical Model
3.1 Problem Description
In the design optimization of GPNs, there are various boundary conditions that must
be satisfied in model solving processes, such as the maximum flow rate and pressure of
CSs, minimum pressure requirement of purification plant, the pipeline design pressure,
and the maximum power of compressors. The task of optimization design is to give an
economical and efficient reconstruction scheme under all kinds of boundary conditions,
which can meet the hydraulic requirements with the lowest costs of investment and
operation.
To effectively apply this method, the following assumptions are made:
(1) The pressure ratio and power of CSs are predetermined within a certain range.
(2) The size of candidate diameters is discrete which complies with the American
Petroleum Institute (API) specification or on-site requirements.
(3) The land is flat in the study area and no obstacles are considered in the construction
processes of new pipelines.
(4) The price of compressors is obtained by linear fitting of the on-site historical data
and the investment of pipeline is calculated by steel consumption.
(5) Loads at supply nodes are given at the maximum loading condition and the pressure
of the purification plant is known.
3.2 Mathematical Model
Objective Function
minF =
c∈C
c g P c T +
aP C
c +b
D C
c
Life
+
i∈I
j∈I
d ∈D
c P
d D P
i,j D i,j,d L i,j
Life
i∈(I −C)
c g P C
i T +
aP C
i +b
Life
D C
i +
i∈(I −C)
c g P T
i T
(4)
The objective function (4) minimizes the total construction and operation costs and
has four parts. The first part is the total modification and operational cost of built compressor stations; the second part is the construction cost of the newly built pipelines; the
third part is the construction and operation cost of new CSs, and the fourth part is the
throttling energy consumption of the gathering stations in order to meet the requirement
of compressor inlet conditions. where c g is the power prices and T is the run time; P C
and P T is the power of compressor and throttle loss respectively. Life is the payback
period of the compressors and pipelines. c P
d is the material price of pipelines and L i,j if
the distance between the node i and node j.
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problem, this method finally defines that only one pipeline can be chosen in candidate
pipelines starts from the same node.
3 Problem Description and Mathematical Model
3.1 Problem Description
In the design optimization of GPNs, there are various boundary conditions that must
be satisfied in model solving processes, such as the maximum flow rate and pressure of
CSs, minimum pressure requirement of purification plant, the pipeline design pressure,
and the maximum power of compressors. The task of optimization design is to give an
economical and efficient reconstruction scheme under all kinds of boundary conditions,
which can meet the hydraulic requirements with the lowest costs of investment and
operation.
To effectively apply this method, the following assumptions are made:
(1) The pressure ratio and power of CSs are predetermined within a certain range.
(2) The size of candidate diameters is discrete which complies with the American
Petroleum Institute (API) specification or on-site requirements.
(3) The land is flat in the study area and no obstacles are considered in the construction
processes of new pipelines.
(4) The price of compressors is obtained by linear fitting of the on-site historical data
and the investment of pipeline is calculated by steel consumption.
(5) Loads at supply nodes are given at the maximum loading condition and the pressure
of the purification plant is known.
3.2 Mathematical Model
Objective Function
minF =
c∈C
c g P c T +
aP C
c +b
D C
c
Life
+
i∈I
j∈I
d ∈D
c P
d D P
i,j D i,j,d L i,j
Life
i∈(I −C)
c g P C
i T +
aP C
i +b
Life
D C
i +
i∈(I −C)
c g P T
i T
(4)
The objective function (4) minimizes the total construction and operation costs and
has four parts. The first part is the total modification and operational cost of built compressor stations; the second part is the construction cost of the newly built pipelines; the
third part is the construction and operation cost of new CSs, and the fourth part is the
throttling energy consumption of the gathering stations in order to meet the requirement
of compressor inlet conditions. where c g is the power prices and T is the run time; P C
and P T is the power of compressor and throttle loss respectively. Life is the payback
period of the compressors and pipelines. c P
d is the material price of pipelines and L i,j if
the distance between the node i and node j.