Experiments Daqing Oilfield unit cryogenic natural gas processing Enforcement

4 sets of equipment cryogenic natural gas processing Daqing oilfield was built are the depth of recovery device light hydrocarbons, which means for the introduction of Sanan cryogenic device, is used in the process of Expansion cooling in two stages, the treatment capacity of 60,104 m3 / d, the other three sets in recent years to recover cold cooling process, more C2 + propane auxiliary construction cryogenic device based light hydrocarbons, extension mechanisms are used. A cryogenic temperature refrigeratiostirred ball milln -101 ℃ Red designed pressure provided around ethane efficiency of 80%, the content of CO 2 moles of less than 15% in the actual operation, the device is much higher than the tone of the CO2 value calculation to 30% above, resulting in the cooling system of the demethanizer unit, coolers, gas and other cooling below -90 ℃ negative conditions temperature occurs block frozen CO2, which leads to the parking lot of the plant, property damage. To avoid frozen block, the device worked over -90 ℃ conditions greatly influenced the light hydrocarbon yield of light hydrocarbon year cut about 2,104 t. North and South -1 pressure goal cryogenic device is put into service in 2005 to replace the Sa from oil and gas processing plant, and further improve the depth of cooling and performance of light hydrocarbons to meet a factory area of ​​energy conservation Daqing oilfield and recycling of hydrocarbon resources of high quality light needs. The device works well, but there are varying degrees of problems: programmable valve serious tumble corrosion; raw gas stream exceeds 7104 m3 / d, the large pressure difference cold box and dust filter angry when the filter is dirty, you can not blowback lead dust in the downstream system will connect the cold box, cooler air and extension, affecting the normal operation of equipment; easy to form a solid sulfide pipe clogged air cooler outlet line, the impact of the flow of regeneration gas. Daqing

currently under construction in the North -2 unit cryogenic natural gas processing to optimize the operation of the cryogenic installation above problems. The process technology and below to explore the characteristics of the device.

2 processes and features

North -2 using first treatment plant gas, gas pressure, molecular sieve depth dehydration, expansion and propane auxiliary cryogenic cooling process the refrigerant. A gas treatment system according to the oil processing can be divided into the compression zone, dewatering zone and the separation zone frozen. Main unit area three lines arranged in the middle of the pipe grate belt, pipe rack for installation side of the feed gas compressor; other side of the object image and separation of the refrigeration plant, a molecular sieve dehydration emobile crusher functionquipment area.

2.1

process gas in the feed gas compressor separator inlet separated oil, water and impurities, The centrifugal compressor stage of the three compression to 39 MPa, cooling levels compressors using air cooling, air cooling of the frequency control according to facilitate energy saving. After three export gas via a water cooled by cooling air after the cooling to 40 ℃ after the compressor outlet separator after entering the dewatering unit.

Compressed gas through the filter, wherein the hydrocarbon separator to remove water droplets, followed by dehydration in the adsorption vessel. Dehydration process using two rounds, by switching the control valve switching DCS-time is completed, the adsorption and regeneration are used to dry cooling. Adsorber regeneration gas and air for cooling the compressor drive expander coaxial dry gas outlet. When the reproducing operation, this portion of the regeneration gas directly into the dry gas heater, anger heated desiccant entering the adsorber to remove adsorbed water, and then cooled by air cooling, then angry The regeneration gas is separated water condensation container, during the cooling operation, the cold and dry air blowing cooling gas 40 ℃ after the dry gas in the adsorber is regenerated after operation cooling, through the outlet of the cooling after the adsorption separation of regeneration gas, cooling air return inlet to the external dry gas; two towers cycles satisfying continuous drying purposes. After filtering the dust in the dry air filter, go to the cryogenic separation unit. Dehydrated raw gas

of

were divided into two heat exchangers: the way into the primary heat exchanger exchanger and gas rich gas heat head, another way through the bottom reboiler and After the first side reboiler streams mixed in the refrigeration unit to propane, and then to a liquid-gas separator at low temperatures. After entering the top of the demethanizer liquid-liquid separation, the level control valve absorbed in the upper part of the reflux to the demethanizer as cold too, the turbo-expander gas expands upon absorption in the section methane separation between the article and the tower, as the burden of the demethanizer column. Dry gas demethanizer overhead via the heat exchanger, then through the coaxial extension extra biasing drive, as a part of a gas processing plant fuel gas, and the dry product gas remaining gas as a means entering the pipeline dry gas outside. Demethanizer abutting light hydrocarbons through the outlet of the pressure vessel bottom pump light hydrocarbons.

2.2 Characteristics of the process of natural gas processing, raw material components of factors, financing, size, location, the use of technology, equipment, process control methods are different, have their own characteristics. North - 2 gas treatment device designed taking into account the factors above, follow the principle of maximizing efficiency, using conventional equipment and unique technology to obtain a higher return. A method of cryogenic apparatus has the following characteristics:

processing gas oil using the gas supply pressure, a molecular sieve dehydration, expansion and technology auxiliary propane refrigeration, raw materials for the boost pressure of the low air can reach a depth of cooling, the variation of the component gas adapt flexibility, ease of control parameters operating.

Compressor gas

power using hydraulic actuators coupling, can effectively reduce the compressor power, reduce energy consumption, reduce compressor starts impact on the power adjust the delivery system to adapt the rotational speed of the compressor in the range of fluctuations of gas. Demethanizer separation equipment using structured packing with a high strength liquid dispenser or high plateaus of operating flexibility, the ability to adapt to changes and fluctuations in load.

To maximize the use of cooling technology of cooling air for power saving. After cooling, the compressor outlet gas cooling method using an air-cooled with water and then cooled, both the heat transfer to the cooled solution increases the air temperature difference, reducing the number of units of the air cooler, but also to ensure that the temperature of the cooled gas and cold, the temperature stable. The reboiler heat at low temperature heat recovery bit in the raw gas obtained in the reboiler, the reboiler and bottom reboiler of a side stream is mixed with the thermal dehydration can effectively recover refrigeration, reducing consumption energy.

Use an RSS supercooled liquid reflux. Cryogenic demethanizer overhead gas is first separated from the separator to the heat transfer to the input of the regulator of light hydrocarbons, such as light hydrocarbon subcooled methane in the column as reflux to the part higher, and to improve the temperature of the outlet of the expander head demethanizer, this process can be energy saving; Meanwhile, the composition of rich reflux head played a role in the absorption of oil, an increase in the solubility of CO2 in light hydrocarbons, Expansion demethanizer main exports and generate CO2 dry ice area has played in some extent.

Separator before the addition of the vertical separator filter larger volume, the air compressor is effectively separated from the entrained secondary air cooling after the free water and heavy hydrocarbons, avoid overloading the molecular sieve adsorption, which prolongs the life of the molecular sieve. 3 Conclusion

Institute of Daqing depth summary of other cryogenic devices running problems, improve the design, to ensure that the North - two natural processing unit optimized to run gas production will create greater economic benefits. Meanwhile, the construction unit slowed in September coolers shallow shallow and aircraft transporting cooling loads north, the northern region to remove moisture ventilation during plant maintenance issues to improve yet the gas field Daqing Petroleum, network air ducts, improve the reliability of the distribution of the oil field and flexibility, the development of oil fields will have a profound impact.