Heat recovery liquid nitrogen evaporation system suitable for oil and gas fields

Abstract

The invention belongs to the technical field of oil and gas field development equipment, and particularly relates to a novel heat recovery liquid nitrogen evaporation system suitable for oil and gas fields. The novel heat recovery liquid nitrogen evaporation system comprises a relatively independent evaporation system and a heat recovery system, wherein the evaporation system and the heat recoverysystem are connected through a heat exchanger, and the evaporation system and the heat recovery system exchange heat by the heat exchanger; the heat recovery system comprises an air heat exchanger, aheat pump compressor and an expansion valve which are sequentially connected to a first medium transmission pipeline; and the evaporation system comprises a liquid storage tank, a booster pump and anevaporator which are sequentially connected to a second medium transmission pipeline. The novel heat recovery liquid nitrogen evaporation system keeps the operation process clean, the requirements ofenvironmental protection are met, the power consumption in the operation process is greatly reduced, and the operation cost is saved.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development equipment, in particular to a heat recovery liquid nitrogen evaporation system suitable for oil and gas fields. Background technique [0002] Nitrogen is non-flammable, explosive, non-corrosive, low-melt in oil or water, and non-toxic and non-polluting. Therefore, it is widely used in oil and gas fields, and the technology of liquid nitrogen booster equipment that can provide high-purity nitrogen has developed rapidly. The principle of the liquid nitrogen pressurization equipment is to pressurize the finished liquid nitrogen through the pump, and the pressurized liquid nitrogen is gasified through heat exchange in the evaporator to provide high-purity nitrogen for oil and gas field operations. [0003] At present, the heat of the evaporation system on the liquid nitrogen pressurized equipment comes from the following ways: one is to use the heat recovery evaporation system to...

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Problems solved by technology

[0003] At present, the heat of the evaporation system on the liquid nitrogen pressurized equipment comes from the following ways: one is to use the heat recovery evaporation system to recover the waste heat generated during the operation of the equipment's own engine, hydraulic system and lubrication system, and the recycled The heat of the liquid nitrogen is vaporized in the water-bath evaporator. This way of working is energy-saving and the equipment is compact in structure. However, with the improvement of environmental protection requirements for equipment emissions, engine emissions are also getting higher and higher. Under the same power, it can Recovered waste heat is reduced, equipment manufacturing costs and operating costs are greatly increased, and it is not conducive to environmental protection; the second is to use a direct-fired evaporator, that is, to use the heat generated by the combustion of fuel in the direct-fired evaporator to gasify liquid nitrogen. There is direct flame combustion in the evaporator, which cannot meet the explosion-proof requirements and is not conducive to environmental protection; the third is to use an air-heated evaporator to vaporize liquid nitrogen through the heat in the air, and the nitrogen discharge temperature is generally lower than the ambient temperature 15°C, the scope of application is small, and most of them adopt the combination of air heat exchange and electric auxiliary heat, but because the surface of the air-heated evaporator is frosted during the heat exchange process, the continuous operation time generally does not exceed 8 hours, and the equipment is large in size , the transportation is inconvenient; the fourth is to use electric heating to transfer the heat generated by the electric heater to the evaporator through the medium to vaporize the liquid nitrogen, which can meet the environmental protection requirements, but the power consumption of the operation is too large, and the 180K commonly used in oil and gas fields Take liquid nitrogen equipment as an example. The electric power only used for liquid nitrogen gasification is above 600KW. It is inconvenient to obtain electricity at the work site and the operation cost is high.

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