Technical And Economic Research On Natural Gas Supply In Small Towns

With the adjustment of China's energy structure,the demand for natural gas is becoming more and more obvious.Compressed natural gas(CNG)gas supply technology has obvious advantages under certain conditions.In addition to industrial use,compressed natural gas is also used for automobile fuels and gas supply for small town residents.During the transportation of compressed natural gas,there are still some problems,such as the choice of compressor,improper compressor selection may result in waste of the compressor,or insufficient supply capacity of compressed natural gas;In addition,in the transportation trailer if the equipment is unreasonable,it will lead to an increase in investment and expenses.These economic problems have largely limited the use and promotion of compressed natural gas.In this paper,through the analysis of economic indicators,a mathematical model to determine the effective gas supply radius was established,and optimization analysis was carried out.The logistics mode of compressed natural gas is studied and the compressor combination schemes are compared,and the effective gas supply radius of compressed natural gas is determined.The main contents of this paper include:(1)The advantages of compressed natural gas supply and transportation economy were analyzed,and the advantages of CNG compared with LNG,LPG and pipeline natural gas were compared.The economic evaluation of CNG transportation was established,and the parameters of economic transportation range and critical point of PNG,LNG and CNG were determined.The results show that above the economic transportation critical curve of pipeline natural gas and liquefied natural gas and pipeline natural gas and compressed natural gas,the unit transportation cost of pipeline natural gas is the lowest;the initial investment of compressed natural gas is the smallest,but the operation cost of trailer is high,so the economy of small-scale transportation is better,in pipeline natural gas and liquefied day.Between the economic transportation critical curve of natural gas transportation and the economic transportation critical curve of liquefied natural gas and compressed natural gas transportation,the unit transportation cost of liquefied natural gas is the lowest;under the economic transportation critical curve of pipeline natural gas and compressed natural gas transportation and the economic transportation critical curve of liquefied natural gas and compressed natural gas transportation,the unit transportation cost of compressed natural gas is the lowest.At the intersection of the three critical curves,L is 244 km and q is 12×10~4Nm~3/d.At this point,the unit gas transmission cost of the three modes of transportation is equal.(2)The economic scale of compressed natural gas for civil gas supply in small towns is determined.Based on this,the vehicle scheduling algorithm is optimized to simplify the minimum number of trailers to meet the traffic volume,so as to continuously optimize the mathematical model.Then,the number and type of compressors are optimized in terms of economic scale parameters,production adaptability and economic gas consumption units.The logistics model of the transport trailer and the optimal model of the trailer are used to calculate the transportation cost and the transportation cost under the conditions of different distances and different gas supply scales.The results show that for the same gas supply scale,the farther the transportation distance is,the higher the transportation cost is.For the same distance,the bigger the gas supply scale is,the lower the transportation cost is.(3)The mathematic model of effective gas supply radius of compressed natural gas is deduced in turn,and the mathematic model of transportation radius transmission of compressed natural gas is established.The relationship between effective radius of natural gas supply and gas supply scale,raw gas price and gasoline price is deduced according to actual production constraints.The effective gas supply radius of compressed natural gas under different user numbers is obtained,and the calculation error is analyzed.The results show that the R value of effective radius of compressed natural gas supply decreases with the increase of feed gas price.When the number of gas suppliers is 32,000,the effective radius of gas supply is 39.7824-1233.254 km when the price of raw gas is 2.0-3.8 yuan per cubic meter and the price of gasoline is 7.5 yuan per liter.The R value of effective radius of compressed natural gas supply decreases with the increase of gasoline price.When the number of gas suppliers is 32000,the effective radius of gas supply is 364.674-1094.016 km in the range of3.00-9.00 yuan per liter of gasoline and 3.2 yuan per cubic meter of raw gas.