Flow control method of cold source liquefied natural gas in a cold energy supply system

Abstract

The invention discloses a flow control method of a cold source liquefied natural gas of a cold energy supply system. The method is used for adjusting the cold energy supply system. The cold energy supply system includes a heat exchange element and a downstream heat exchanger. When the change value of the heat transfer amount of the downstream heat exchanger within a certain period of time is not greater than the preset value, the flow rate of the liquefied natural gas is controlled to be constant, and the temperature of the liquefied natural gas at the inlet of the liquefied natural gas and the temperature of the outlet of the liquefied natural gas are set constant. The flow rate of the refrigerant is set constant so that the supply water temperature of the brine is in the range of -21°C to -27°C; The flow rate of the refrigerant and the flow rate of the liquefied natural gas are kept constant, so that the supply water temperature of the brine is in the range of -21°C to -27°C. The method stores the cold energy of the liquefied natural gas through the temperature change of the brine, and provides stable cold energy for downstream facilities with changing cooling loads.

Description

technical field [0001] The invention relates to the technical field of liquefied natural gas cooling, in particular to a flow control method of a cold source liquefied natural gas of a cold energy supply system. Background technique [0002] Due to its high efficiency, high quality, clean performance and wide range of uses, natural gas has become a safe and clean energy that is generally favored by countries all over the world. After liquefaction, the volume of natural gas is reduced to 1 / 600 of its original volume, which is convenient for long-distance transportation. After the liquefied natural gas is transported to the station by ship, it needs to convert the liquefied natural gas into a gaseous state, and release about 830-860MJ / t of cold energy during the process. The traditional method is When the liquefied natural gas is directly gasified through the seawater vaporizer, a large amount of cold energy is taken away by the seawater without being used, and it also aggrava...

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Problems solved by technology

After liquefaction, the volume of natural gas is reduced to 1 / 600 of its original volume, which is convenient for long-distance transportation. After the liquefied natural gas is transported to the station by ship, it needs to convert the liquefied natural gas into a gaseous state, and release about 830-860MJ / t of cold energy during the process. The traditional method is The liquefied natural gas is directly vaporized through the seawater vaporizer, and a large amount of cold energy is taken away by the seawater without being used, and it also aggravates ocean low-temperature pollution

However, when the cooling energy of liquefied natural gas is used for the cooling load demand of downstream facilities, since the cooling load of downstream facilities will change greatly at different times, and the frequency of change is fast and the range of change is large, the corresponding flow rate of liquefied natural gas The demand fluctuates greatly, which affects the normal operation of the upstream receiving station

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